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RETRACTED: Menatetrenone ameliorates osteopenia in disuse-affected limbs of vitamin D- and K-deficient stroke patients
Bone Vol. 23, No. 3 September 1998:291–296
Menatetrenone Ameliorates Osteopenia in Disuse-Affected Limbs of Vitamin D- and K-Deficient Stroke Patients Y. SATO,1 Y. HONDA,1 H. KUNO,1 and K. OIZUMI2 1 2
Department of Neurology, Futase Social Insurance Hospital, Iizuka, Japan First Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
Introduction Significant reduction in bone mineral density (BMD) occurs in stroke patients on the hemiplegic and contralateral sides, correlating with the degree of paralysis and vitamin D and K deficiency due to malnutrition, and increasing the risk of hip fracture. We evaluated the efficacy of vitamin K2 (menatetrenone: menaquinone-4; MK-4) in maintaining BMD by comparing serum biochemical indices of bone metabolism between treated and untreated patients. In a random and prospective study, of 108 hemiplegic patients following stroke, 54 received 45 mg menatetrenone daily (MK-4 group, n 5 54) for 12 months, and the remaining 54 (untreatment group) did not. Nine patients excluded from the study. The BMD in the second metacarpals and serum indices of bone metabolism were determined. BMD on the hemiplegic side increased by 4.3% in the MK-4 group and decreased by 4.7% in the untreated group (p < 0.0001), while BMD on the intact side decreased by 0.9% in the MK-4 group and by 2.7% in the untreated group (p < 0.0001). At baseline, patients of both groups showed vitamin D and K1 deficiencies, high serum levels of ionized calcium, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), and low levels of parathyroid hormones (PTH) and bone Gla proteins (BGP), indicating that immobilization-induced hypercalcemia inhibits renal synthesis of 1, 25-dihydroxyvitamin D (1, 25-[OH]2D) and compensatory PTH secretion. Both vitamins K1 and K2 increased by 97.6% and 666.9%, respectively, in the MK-4 group. Correspondingly, a significant increase in BGP and decreases in both ICTP and calcium were observed in the MK-4 group, in association with a simultaneous increase in both PTH and 1, 25-[OH]2D. One patient in the untreated group suffered from a hip fracture, compared with none in the MK-4 group. The treatment with MK-4 can increase the BMD of disused and vitamin D- and K-deficient hemiplegic bone by increasing the vitamin K concentration, and it also can decrease calcium levels through inhibition of bone resorption, resulting in an increase in 1, 25-[OH]2D concentration. (Bone 23:291–296; 1998) © 1998 by Elsevier Science Inc. All rights reserved.
In a previous study we found that four factors figure significantly in the reduced bone mineral density (BMD) on the hemiplegic side compared with the contralateral side in patients following a stroke:22–26 (1) disuse due to paralysis, (2) vitamin D deficiency due to malnutrition, sunlight deprivation, and immobilizationinduced hypercalcemia, (3) compensatory hyperparathyroidism, and (4) vitamin K deficiency due to malnutrition. We also showed that a 1.0 mg daily dose of alfacalcidol (an active form of vitamin D3) can reduce the risk of hip fractures frequently occurring on the hemiplegic side in this population, and can prevent a further decrease in BMD on the hemiplegic side of patients with a long-standing stroke.27 Since Bouckaert and Said first reported the effect of vitamin K on fracture healing in 1960, several studies have suggested that this vitamin affects bone metabolism. Vitamin K is essential to site-specific carboxylation of bone Gla protein (BGP) and other bone matrix proteins.28,33 As a biochemical indicator of compromised vitamin K status, reduced serum BGP concentration has been associated with a reduced bone mineral density (BMD) at the hip32 and increased risk of fracture31 in otherwise healthy adults. In patients who had sustained fractures, especially at the hip, serum vitamin K concentrations have been found to be lower than in age-matched controls.4,10 –12 It has been demonstrated that treatment with vitamin K2 (menatetrenone; menaquinone-4; MK-4) is more effective in increasing BMD than alfacalcidol in involutional osteoporosis.19 We conducted a 12-month randomized trial to evaluate the efficacy of menatetrenone in reducing the severity of the osteopenia in the second metacarpals and in decreasing the risk of hip fractures in stroke patients with hemiplegia. Materials and Methods For this study we selected 108 outpatients with hemiplegia following strokes who had been examined at the Futase Social Insurance Hospital. All had suffered a stroke within the preceding 2 years. We determined the body mass index (BMI) and Barthel index (BI)14; the latter is a functional dependence score in which a score of 100 represents independence, while a score of 0 represents total independence. Clinical severity of the hemiplegia was evaluated using Brunstrom’s staging classification,5 in which a score of 1 is defined as paralysis of the fingers and leg, while a score of 6 represents normal strength. The diagnosis of the stroke was based on the results of clinical evaluation, including mode of onset, neurological examination, and computed tomography (CT) scans performed in the acute
Key Words: Hemiplegia; Menatetrenone; Osteopenia; Stroke; Vitamin D; Vitamin K.
Address for correspondence and reprints: Dr. Yoshihiro Sato, Department of Neurology, Kurume University Medical Center, 155-1 Kokubumachi, Kurume 839-0863, Japan. E-mail: [email protected] © 1998 by Elsevier Science Inc. All rights reserved.
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8756-3282/98/$19.00 PII S8756-3282(98)00108-2
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and chronic phases of the disorder. The strokes were classified according to the Classification of Cerebrovascular Diseases III of the National Institute of Neurological Disorders and Stroke.29 Patients with strokes were excluded if they showed other known causes of osteoporosis, such as hyperparathyroidism or renal osteodystrophy, and impairment of hepatic, renal, cardiac, or thyroid function. Also excluded were patients with a history of therapy with warfarin, corticosteroids, estrogens, calcitonin, etidronate, calcium, vitamin D, or anticonvulsants for 3 months or longer during the 12 months preceding the study. If therapy of this nature occurred during the 2 months immediately preceding the study, even brief treatment was cause for exclusion. Thirtyfive age-matched volunteers (17 men and 18 women) served as healthy controls. The study was approved by the institutional ethics committee, and informed consent was obtained from all study subjects in the presence of a witness. The patients were randomly assigned either to the menatetrenone (n 5 54) or the untreated (n 5 54) group. No placebo capsules were administered. Menatetrenone at a daily dose of 45 mg/day was given to the treatment group. No dose adjustments were made at any time in the study. The two groups were observed for 12 months of treatment. The patients’ clinical status was assessed at baseline and followed up every 2 weeks, at which times clinical status was assessed, and hip fractures were recorded. Three patients in the treatment group and six in the untreatment group dropped out or withdrew from the study due to noncompliance, loss to followup, or intercurrent illness. Thus, a total of 99 patients (51 in the treatment group and 48 patients in the untreated group) completed the trial. The starting and final data for the subjects were analyzed. Medical and bone evaluations performed before randomization were used for the determination of baseline values. Using a computed X-ray densitometer (CXD; Teijin, Tokyo),16 the BMD of the second metacarpal was measured in both hands. The CXD method measures bone density at the middle of the second metacarpal using a radiograph of the hand relative to an aluminum step wedge used as a standard (20 steps, 1 mm/ step). The computer algorithm compares bone radiodensity with the gradations of the aluminum step wedge, calculating bone thickness as an aluminum equivalent (mm Al) with the same X-ray absorption. On the day of bone evaluation, a fasting blood sample was obtained in 54 patients taking menatetrenone, 54 patients without treatment, and 35 healthy controls. Blood samples were analyzed for vitamins K1 and K2, intact parathyroid hormone (PTH), ionized calcium, intact BGP, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), 25-hydroxyvitamin D (25-OHD), 1, 25-dihydroxyvitamin D (1, 25-[OH]2D), and albumin. Circulating levels of vitamin K including vitamin K1 (phylloquinone) and vitamin K2 (menaquinone-4; MK 4) were measured by high-performance liquid chromatography according to the method of Langenberg and Tjaden.13 When vitamin K2 was undetectable, attempts were made to detect it in the concentrated serum. Serum PTH was measured by a radioimmunoassay (RIA; Nichols Institute Diagnostics, San Juan Capistrano, CA; normal range for control individuals in our laboratory, 19 –54 pg/mL). Ionized calcium in serum prepared freshly under anaerobic conditions was measured using an ion-selective electrode and an ionized calcium analyzer (NOVA Biochemical, Newton, MA; normal range 2.313–2.515 mEq/L). Intact BGP was measured with an established enzyme immunoassay using antibodies to Nand C-terminal regions of human BGP (Teijin Diagnostics, Tokyo; normal range 6.6 –15.4 ng/mL). ICTP was measured by RIA (Orion Diagnostica, Oulunsalo, Finland; normal range 2.0 –
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3.2 ng/mL). Serum 25-OHD was determined using a competitive protein-binding assay, and 1, 25-[OH]2D was determined by a radioreceptor assay using a calf thymus receptor (Nichols Institute Diagnostics). Sunlight exposure during the preceding year was assessed by a questionnaire administered to patients or family members, and was graded as either almost none (less than 15 min per week) or longer. Additionally, the mean weekly dietary vitamin D intake was estimated for each individual. All statistical procedures were performed using the Statview 4.11 software packages (Abacus Concepts, Berkeley, CA). Data are presented as the mean 6 standard deviation (SD). One-way analysis of variance (ANOVA) and Fisher’s protected least significant difference were used to assess baseline differences between three groups. Group differences of the categorical data were tested by x2 analyses. The paired t-test was used to assess the significance of the differences of BMDs between intact and hemiplegic sides. To examine a possible correlation between BMD on both sides and vitamins K, BGP, 25-OHD, and ionized calcium concentrations and the degree of paralysis, or BI, between serum calcium level and BI and 1, 25-[OH]2D concentration, and between PTH and 25-OHD, Spearman’s rank correlation coefficients (SRCC) were calculated. To examine the correlation between vitamin D metabolite levels and albumin, SRCC was calculated between the 1, 25-[OH]2D concentration and albumin. Correlations (SRCC) of ionized calcium, ICTP, and BGP with duration of illness were also calculated. For BMD measurements individual values and laboratory values were computed and expressed as a percent change from the baseline. The two groups were then compared with respect to BMD and the laboratory values by using the Wilcoxon rank sum test. The difference of hip fracture rate between the two groups for 12 months was tested by Fisher’s exact test. p values of less than 5% were considered statistically significant. Results Baseline Characteristics of Study Subjects (Tables 1 and 2) Demographic and baseline clinical features of study patients and healthy control are presented in Tables 1 and 2. The three groups showed identical composition with respect to age and gender. There were also no significant differences between the two patient groups in duration of illness, BI, degree of hemiplegia, BMI, type of stroke, BMD, and serum indices of bone metabolism. At the baseline, the BMDs on the hemiplegic side were significantly lower than those on the intact side and those of the controls, as also observed in previous studies.22–27 Also, in the two patient groups, the baseline values of serum vitamin K1, PTH, BGP, albumin, and 25-OHD concentrations were low, and the value of 1, 25-[OH]2D was at a level of low normal, while the value of serum K2 was normal. The value for ionized calcium was elevated in 40 patients (74%) of the untreated group and in 41 patients (76%) of the treated group. The ICTP value was high in 47 untreated patients (87%) and in 48 treated patients (89%). Reduced mobility with a mean BI of 78 –79 prevented the patients from venturing outdoors, and 83 (84%) of 99 patients had been exposed to sunlight for less than 15 min per week; 76 patients (77%) consumed less vitamin D than the Japanese recommended daily allowance (100 IU). BMI were significantly lower in patients than in control subjects. All 46 female patients were postmenopausal. BMD values were significantly lower in females than in males: 1.899 6 0.465 vs. 2.312 6 0.385 on the hemiplegic side (p , 0.0001); 2.110 6 0.392 vs. 2.484 6 0.342 on the contralateral side (p , 0.0001) in both treated and untreated groups. No differences were observed
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Table 1. Demographic and baseline clinical charact eristics of control subjects and hemiplegic patients with stroke at study entry
Characteristic Age (years) Gender (M/F) Duration of illness (months)c Body mass index (kg/m2) Barthel index Degree of hemiplegia Finger Leg Type of stroke (bleeding/infarction) Sunlight exposure 15 min . (%) 15 min , or none (%) Dietary intake of vitamin D Less than 100 IU (%)
Control (n 5 35)
Untreated (n 5 54)
Menatetrenone-treated (n 5 54)
p value
66.8 6 6.1 17/18 22.9 6 1.8 -
65.6 6 7.3 23/31 13.2 6 7.8 19.4 6 1.8b 78 6 28
66.3 6 6.0 25/29 13.9 6 6.4 19.9 6 1.7b 79 6 27
0.69a 0.70 0.88 ,0.0001a 0.81
-
3.1 6 1.8 4.4 6 1.3
3.0 6 1.6 4.2 6 1.2
0.82 0.52
-
19/35
17/37
0.68
33 (94) 2 (6)
9 (17) 45 (83)
7 (13) 47 (87)
0.59
2 (6)
36 (67)
38 (70)
0.68
a
ANOVA. p , 0.0001 vs. controls. As the day the patient first experienced hemiplegia was defined as the onset of stroke, the duration of illness was defined as the duration of both hemiplegia and stroke in the two groups. b c
between male and female patients in age, duration of illness, BI, degree of finger paralysis, or BMI. No significant gender-related differences were noted in serum concentrations of K1, K2, PTH, ionized calcium, BGP, ICTP, 25-OHD, 1, 25-[OH]2D, or albumin. When the treated and untreated patients were analyzed together, the BMD on the hemiplegic side correlated positively with K1 (r 5 0.290, p 5 0.0041), BGP (r 5 0.311, p 5 0.0012), 25-OHD (r 5 0.436, p , 0.0001), and calcium (r 5 20.290, p 5 0.0041) concentrations, degree of finger paralysis (r 5 0.264, p 5 0.0088), and with BI (r 5 0.205, p 5 0.0426). On the intact side, BMD correlated only with 25-OHD (r 5 0.324, p 5 0.0003). There were correlations between the serum ionized calcium level and BI (r 5 20.362, p 5 0.0002), ICTP (r 5 0.358, p 5 0.0004), or the 1, 25-[OH]2D (r 5 20.318, p 5 0.0016) concentrations. The BI score correlated with ICTP (r 5 20.248, p 5 0.0140). No correlation between the serum level of PTH and 25-OHD concentrations was observed (p 5 0.91), indicating that compensatory hyperparathyroidism did not occur.
A positive correlation between 1, 25-[OH]2D and albumin levels was observed (r 5 0.257, p 5 0.0108), indicating a low level of the vitamin D binding protein (not determined in the present study) was also responsible for hypovitaminosis D. Duration of illness correlated negatively with ionized calcium (r 5 20.215, p 5 0.0350) and ICTP (r 5 0.273, p 5 0.0075), but not with BGP (r 5 20.052, p 5 0.61). Bone Changes and Serum Biochemical Markers (Table 3) Percent changes in BMD on the hemiplegic side were 14.3 6 9.9 in the menatetrenone group and 24.7 6 7.6 in the untreated group. On the nonhemiplegic side, percent changes in BMD were 20.9 6 3.6 in the treated group and 22.7 6 2.9 in the untreated group. The differences of changes of BMD on both sides between the menatetrenone-treated group and the untreated group were statistically significant (p , 0.0001 and p 5 0.0011). During the 12-month study period, not only K2 but also K1 increased significantly in the menatetrenone-treated group but
Table 2. Bone mineral density and various serum biochemical tests of control subjects and two groups of stroke patients at baseline
Bone mineral density (mm Al) Hemiplegic side Intact side Ionized calcium (mEq/L) Parathyroid hormone (pg/mL) Albumin (g/dL) Vitamin K1 (ng/mL) Vitamin K2 (ng/mL) 25-OHD (ng/mL) 1, 25-[OH]2D (pg/mL) Intact BGP (ng/mL) ICTP (ng/mL)
Control
Untreated
Menatetrenone-treated
p valuea
2.854 6 0.423 2.885 6 0.426 2.414 6 0.101 35 6 16 4.5 6 0.3 0.562 6 0.682 0.073 6 0.165 21.6 6 3.1 49.6 6 9.4 11.0 6 4.4 2.6 6 0.6
2.109 6 0.407b,c 2.327 6 0.248b 2.584 6 0.070b 28 6 15d 3.8 6 0.5b 0.226 6 0.081b 0.087 6 0.201 9.8 6 3.2b 23.6 6 6.8b 3.5 6 2.4b 8.8 6 2.7b
2.130 6 0.635b,c 2.294 6 0.558b 2.585 6 0.107b 26 6 11d 3.9 6 0.3b 0.215 6 0.089b 0.084 6 0.182 9.7 6 3.5b 23.8 6 10.8b 3.7 6 1.9b 8.6 6 3.7b
,0.0001 ,0.0001 ,0.0001 0.020 ,0.0001 ,0.0001 0.96 ,0.0001 ,0.0001 ,0.0001 ,0.0001
Values are mean 6 SD. ANOVA. p , 0.0001 vs. controls. c p , 0.0001 vs. intact side. d p , 0.05 vs. controls. 25-OHD 5 25-hydroxyvitamin D; 1, 25-[OH]2D 5 1, 25-dihydroxyvitamin D; BGP 5 bone Gla protein; ICTP 5 pyridinoline cross-linked carboxyterminal telopeptide of type I collagen. a
b
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Table 3. Bone mineral density and laboratory values and changes of 99 subjects who completed study Percent change after 12 months followup (values at 12 months)
Bone mineral density (mm Al) Hemiplegic side Intact side Ionized calcium (mEq/L) Intact PTH (pg/mL) Vitamin K1 (ng/mL) Vitamin K2 (ng/mL) 25-OHD (ng/mL) 1, 25-[OH]2D (pg/mL) Intact BGP (ng/mL) ICTP (ng/mL)
Untreated (n 5 48)
Menatetrenone-treated (n 5 51)
p valuea
24.7 6 7.6 (2.024 6 0.481) 22.7 6 2.9 (2.261 6 0.228) 0.4 6 1.9 (2.589 6 0.069) 4.4 6 6.3 (24 6 11) 2.4 6 4.2 (0.225 6 0.098) 21.7 6 4.2 (0.081 6 0.162) 23.3 6 2.3 (9.4 6 2.8) 21.7 6 0.6 (29.4 6 10.7) 24.6 6 3.3 (3.3 6 2.3) 22.1 6 17.4 (8.6 6 2.99)
4.3 6 9.9 (2.173 6 0.546) 20.9 6 3.6 (2.273 6 0.561) 24.2 6 6.1 (2.473 6 0.123) 70.4 6 97.4 (38 6 14) 97.6 6 29.2 (0.320 6 0.238) 669.7 6 218.3 (26.1 6 27.2) 23.5 6 1.5 (9.3 6 3.7) 16.9 6 16.5 (33.3 6 11.9) 217.5 6 126.9 (6.4 6 2.1) 232.0 6 12.6 (6.1 6 3.0)
,0.0001 ,0.0001 ,0.0001 ,0.0001 ,0.0001 ,0.0001 0.91 ,0.0001 ,0.0001 ,0.0001
Values are mean 6 SD. p 5 Wilcoxon rank sum test.
a
not in the untreated group, and no significant difference in percent changes of 25-OHD between the two groups was observed. Ionized calcium, PTH, and BGP were also increased while ICTP was decreased significantly in the menatetrenonetreated group, as compared with the untreated group. Unexpectedly, 1, 25-[OH]2D was increased significantly in the treated group as compared to the untreated group. Fracture Incidence A hip fracture occurred on the hemiplegic side of a female patient in the untreated group. No hip fractures were recorded in the menatetrenone-treated group. The incidence of hip fractures was not significantly different between the two groups (p 5 0.48; 0/50 vs. 1/48). Fractures other than of the hip were not observed in either group. Discussion In the present study we found both vitamins D and K1, BGP, the degree of paralysis, calcium levels, and BI correlated with BMD in bones affected by disuse on the hemiplegic side in stroke patients. On the nonhemiplegic side, only 25-OHD correlated with BMD. Prolonged immobilization from spinal cord injury has long been known to result in hypercalciuria, hypercalcemia, accelerated bone resorption, and osteoporosis.2,3,6,7,17,18,30 Reduction in bone formation is evidenced by diminished osteoid thickness and mineralization rates observed in biopsy specimens.17 On the other hand, in vitamin D deficiency, bone mineralization is impaired, leading to accumulation of an unmineralized matrix or osteoid in the skeleton. In the present study, immobilization-induced hypercalcemia,30 as evidenced by a negative correlation between BI and serum levels of ionized calcium, may inhibit compensatory PTH secretion and thus 1, 25-[OH]2D production. Hypercalcemiainduced inhibition of 1, 25-[OH]2D production in the kidney may result in a low normal of 1, 25-[OH]2D. Both disuse-affected and vitamin D-deficient bone must be present on the hemiplegic side in the patients studied here. Serum BGP was depressed in patients and correlated well with the decrease in BMD in spite of the presence of hypovitaminosis D with an increased level of ICTP in the present study. This is explained by the two mechanisms. First, low vitamin K stores result in the reduction of BGP carboxylation. Second,
hypercalcemia inhibits the production of 1, 25-[OH]2D, resulting in subnormal vitamin D levels. 1, 25-[OH]2D is needed to enhance the synthesis of osteoblast-derived BGP and matrix BGP.8,20 Thus, BGP production is reduced when both vitamin K and 1, 25-[OH]2D concentrations are low as in the present state, representing a combination of disuse and osteomalacia, which may account for the close correlation between lowered BMD and decreased BGP concentration. On the other hand, an increased level of ICTP observed in many patients in both groups implies increased bone resorption due to immobilization, because there was a close correlation between ICTP and BI. Also, because illness duration correlated negatively with ionized calcium and ICTP, a high rate of bone resorption may occur during the early stages of a stroke. Because calcium was correlated with both BI and ICTP, immobilization hypercalcemia would be the reflection of increased bone resorption. The vitamin K1 deficiency in the patient groups was considered to reflect generally poor nutrition, as evidenced by low serum concentrations of 25-OHD and albumin. Treatment with menatetrenone is more effective than alfacalcidol in increasing BMD in involutional osteoporosis.19 For 6 months, the BMD of metacarpal bone, measured by the microdensitometric method, increased to 1.28% 6 1.52% in patients treated with menatetrenone and decreased to 23.85% 6 2.21% in the untreated group. Also, in a study19 that compared the effect of menatetrenone at a daily dose of 45 mg of K2 with that of 1 mg of alfacalcidol for 48 weeks, metacarpal BMD was found to be increased to 2.05% 6 1.05% in the menatetrenone-treated group while it decreased by 22.42% 6 1.23% in the alfacalcidol-treated group. The routine use of menatetrenone (45 mg/day) in patients with poststroke hemiplegia may be beneficial for several reasons, as suggested by this study. First, BMD on the hemiplegic side increased by 4.3% 6 9.9% in the treated group and decreased 4.7% 6 7.6% in the untreated group (p , 0.0001), while BMD on the intact side decreased by 0.9% 6 3.6% in the treated group and by 2.7% 6 2.9% in untreated groups (p 5 0.0011). Second, menatetrenone significantly increased serum concentrations of vitamin K, not only K2 but also K1. Orally administered K1 is partially transformed into MK-4,21 but a converse transformation has not been observed. Although the precise reason in unknown, administration of a daily dose of 45 mg of vitamin K2 may result in an increase of serum concentration of vitamin K1. Finally, improvement of hypercalcemia by the treatment re-
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sulted in increased serum concentrations of PTH, 1, 25-[OH]2D, and thus BGP. Increased BGP by treatment was attributed to increased vitamin D and K and to release from inhibited compensatory hyperparathyroidism. Conversely, decreased ICTP after the treatment may be due to the inhibitory effect of menatetrenone itself on bone resorption. Indeed, menatetrenone inhibits bone resorption through inhibition of prostaglandin E2 synthesis in vitro9 and has inhibitory effects on osteoclast-like cell formation in mouse bone marrow cultures.1 Menatetrenone increased BMD on the hemiplegic side, but decreased it on the nonhemiplegic side. Our previous study of 1 mg of alfacalcidol on poststroke hemiplegia demonstrated that BMD on the hemiplegic side decreased by 2.4% in the treatment group and 8.9% in the placebo group (p 5 0.0021), while BMD on the intact side increased by 3.5% and decreased by 6.3% in the treated and placebo groups, respectively (p 5 0.0177).27 Some explanations could account for the discrepancy of the effects between the two agents. The causes of osteopenia may be different between the hemiplegic and intact sides; BMD on the hemiplegic side correlated with vitamins D and K1, BGP, degree of paralysis, calcium, and BI, while BMD on the intact side correlated with vitamin D only. Menatetrenone might increase BMD of the disused hemiplegic limb by increasing vitamins D and K, leading to an increase in bone formation and an inhibition of bone resorption, while it acts on the BMD of the intact side by increasing vitamin D. Administration of menatetrenone to ischemic stroke patients may cause a hypercoagulable state, resulting in increased risk of a secondary ischemic stroke. We evaluated the risk of secondary ischemic stroke in 156 patients with cerebral infarction by administration of a daily dose of 45 mg menatetrenone over a 1.5 year period, and a secondary stroke or myocardial infarction did not occur in any patients (unpublished data, Sato, 1998). Thus, a daily dose of 45 mg menatetrenone may be not harmful to ischemic stroke patients. Metacarpal CXD observations have been validated and found to be generalizable by comparison between metacarpal BMD determined by CXD and vertebral (L2– 4), femoral neck, and overall BMD measurements performed by the better known but less available method of dual-energy X-ray absorptiometry.15 Therefore, the reduction in second metacarpal BMD in stroke patients may reflect a generalized decrease of BMD throughout the skeleton. One hip fracture was observed in the untreated group, while such a fracture did not occur in the treatment group. Although there was no statistically significant difference in the incidence of the fractures between the two groups, the treatment with menatetrenone might reduce the risk of hip fractures in stroke patients with hemiplegia, probably by increasing the BMD of the femoral neck. References 1. Akiyama, Y., Hara, K., Tajima, T., Murota, S., and Morita, I. Effects of vitamin K2 (menatetrenone) on osteoclast-like cell formation in mouse bone marrow cultures. Eur J Pharmacol 263:181–185; 1994. 2. Bergmann, P., Heilporn, A., Schoutens, A., Paternot, J., and Tricot, A. Longitudinal study of calcium and bone metabolism in paraplegic patients. Paraplegia 15:147–159; 1997. 3. Biering-Sørensen, F., Bohr, H. H., and Schaadt, O. P. Longitudinal study of bone mineral content in the lumbar spine, the forearm and the lower extremities after spinal cord injury. Eur J Clin Invest 20:330 –335; 1990. 4. Bitensky, L., Hart, J. P., Catterrall, A., Hodges, S. J., Pilkington, M. J., and Chayen, J. Circulating vitamin K levels in patients with fractures. J Bone Joint Surg 70B:663– 662; 1988. 5. Brunstrom, S. Motor testing procedures in hemiplegia. Based on sequential recovery stages. Am J Phys Ther 46:357–375; 1966.
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6. Chantraine, A., Nusgens, B., and Lapiere, C. M. Bone remodeling during the development of osteoporosis in paraplegia. Calcif Tissue Int 38:323–327; 1986. 7. Claus-Walker, J., Spencer, W. A., Carter, R. E., Halsted, L. S., Meiser, R. H. III, and Campos, R. J. Bone metabolism in quadriplegia: Dissociation between calciuria and hydroxyprolinuria. Arch Phys Med Rehabil 56:327–332; 1975. 8. Fraser, J. D., Otawara, Y., and Price, P. A. 1, 25-dihydroxyvitamin D3 stimulates the synthesis of matrix g-carboxyglutamic acid protein by osteosarcoma cells. J Biol Chem 263:911–916; 1988. 9. Hara, K., Akiyama, Y., Tajima, T., and Shiraki, M. Menatetrenone inhibits bone resorption partially through inhibition of PGE2 synthesis in vitro. J Bone Miner Res 8:535–542; 1993. 10. Hart, J. P., Shearer, M. J., Klenerman, L., Catterall, A., Reeve, J., Sambrook, P. N., Dodds, R. A., Bitensky, L., and Chayen, J. Electrochemical detection of depressed circulating levels of vitamin K1 in osteoporosis. J Clin Endocrin Metab 60:1268 –1269; 1985. 11. Hodges, S. J., Pilkington, M. J., Stamp, T. C. B., Catterall, A., Shearer, M. J., Bitensky, L., and Chayen, J. Depressed levels of circulation menaquinones in patients with osteoporotic fractures of the spine and femoral neck. Bone 12:387–389; 1991. 12. Hodges, S. J., Akesson, K., Vergnaud, P., Obrant, K., and Delmas, P. D. Circulating levels of vitamin K1 and K2 decreased in elderly women with hip fractures. J Bone Miner Res 8:1241–1245; 1993. 13. Langenberg, J. P. and Tjaden, U. R. Improved method for the determination of vitamin K1 epoxide in human plasma with electrofluorimetric reaction detection. J Chromatogr 289:377–385; 1984. 14. Mahoney, F. I. and Barthel, D. W. Functional evaluation: The Barthel index. Md St Med J 14:61– 65; 1965. 15. Matsumoto, C., Kushida, K., Orimo, H., Koshikawa, S., Shiraki, M., Akimoto, T., Inoue, T., and Tagawa, H. A new computed X-ray densitometer and its performance (in Japanese with English abstract). J Clin Exp Med 156:741–742; 1991. 16. Mastumoto, C., Kushida, K., Yamazaki, K., Imose, K., and Inoue, T. Metacarpal bone mass in normal and osteoporotic Japanese women using computed X-ray densitometry. Calcif Tissue Int 55:324 –329; 1994. 17. Minaire, P., Meunier, P., Edouard, C., Bernard, J., Courpron, P., and Bourret, J. Quantitative histological data on disuse osteoporosis. Comparison with biological data. Calcif Tissue Res 17:57–73; 1974. 18. Naftchi, N. E., Viau, A. T., Sell, G. H., and Lowman, E. W. Mineral metabolism in spinal cord injury. Arch Phys Med Rehab 61:139 –142; 1980. 19. Orimo, H., Shiraki, M., Fujita, T., Onomura, T., Inoue, T., and Kushida, K. Clinical evaluation of menatetrenone in the treatment of involuntional osteoporosis—A double-blind multicenter comparative study. J Bone Miner Res 7(Suppl. 1):S122; 1992. 20. Price, P. A., Williamson, M. K., and Lothringer, J. W. Origin of the vitamin K depend bone protein found in plasma and its clearance by kidney and bone. J Biol Chem 256:12760 –12766; 1981. 21. Sakamoto, N., Kimura, M., Hiraike, H., and Itokawa, Y. Changes of phylloquinone and menaquinone-4 in rat liver after oral, intravenous and intraperitoneal administration. Int J Vit Nutr Res 66:322–328; 1996. 22. Sato, Y., Maruoka, H., Honda, Y., Asoh, T., Fujimatsu, Y., and Oizumi, K. Development osteopenia in the hemiplegic finger in patients with stroke. Eur Neurol 36:278 –283; 1996. 23. Sato, Y., Maruoka, H., Oizumi, K., and Kikuyama, M. Vitamin D deficiency and osteopenia in the hemiplegic limbs of stroke patients. Stroke 27:2183– 2187; 1996. 24. Sato, Y., Honda, Y., Kunoh, H., and Oizumi, K. Long-term anticoagulation reduces bone mass in patients with previous hemispheric infarction and nonrheumatic atrial fibrillation. Stroke 28:2390 –2394; 1997. 25. Sato, Y., Fujimatsu, Y., Kikuyama, M., Kaji, M., and Oizumi, K. Influence of immobilization on bone mass and bone metabolism in hemiplegic elderly patients with a long-standing stroke. J Neurol Sci 156:205–210; 1998. 26. Sato, Y., Fujimatsu, Y., Honda, Y., Kuno, H., Kikuyama, M., and Oizumi, K. Accelerated bone remodeling in the patients with poststroke hemiplegia. J Stroke Cerebrovasc Dis 7:58 – 62; 1998. 27. Sato, Y., Maruoka, H., and Oizumi, K. Amelioration of hemiplegia-associated osteopenia over 4 years following stroke by 1 a-hydroxyvitamin D3 and calcium supplementation. Stroke 28:736 –739; 1997. 28. Shearer, M. J. Vitamin K. Lancet 345:229 –234; 1995. 29. Special Report From the National Institute of Neurological Disorders and Stroke. Classification of Cerebrovascular Diseases III. Stroke 21:637– 676; 1990. 30. Stewart, A. F., Adler, M., Byers, C. M., Segre, G. V., and Broadus, A. E.
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Calcium homeostasis in immobilization: An example of resorptive hypercalciuria. N Engl J Med 306:1136 –1140; 1982. 31. Szulc, P., Chapuy, M. C., Meunier, P. J., and Delmas, P. D. Serum undercarboxylated osteocalcin is a marker of the risk of hip fracture in elderly women. J Clin Invest 91:1769 –1774; 1993. 32. Szulc, P., Arlot, M., Chapuy, M. C., Meunier, P. J., and Delmas, P. D. Serum undercarboxylated osteocalcin correlates with hip bone mineral density in elderly women. J Bone Miner Res 9:1591–1595; 1994.
Bone Vol. 23, No. 3 September 1998:291–296 33. Vermeer, C., Jie, K. S. G., and Knapen, M. H. J. Role of vitamin K in bone metabolism. Annu Rev Nutr 15:1–22; 1995.
Date Received: March 10, 1998 Date Revised: May 6, 1998 Date Accepted: May 11, 1998
Menatetrenone Ameliorates Osteopenia in Disuse-Affected Limbs of Vitamin D- and K-Deficient Stroke Patients Y. SATO,1 Y. HONDA,1 H. KUNO,1 and K. OIZUMI2 1 2
Department of Neurology, Futase Social Insurance Hospital, Iizuka, Japan First Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
Introduction Significant reduction in bone mineral density (BMD) occurs in stroke patients on the hemiplegic and contralateral sides, correlating with the degree of paralysis and vitamin D and K deficiency due to malnutrition, and increasing the risk of hip fracture. We evaluated the efficacy of vitamin K2 (menatetrenone: menaquinone-4; MK-4) in maintaining BMD by comparing serum biochemical indices of bone metabolism between treated and untreated patients. In a random and prospective study, of 108 hemiplegic patients following stroke, 54 received 45 mg menatetrenone daily (MK-4 group, n 5 54) for 12 months, and the remaining 54 (untreatment group) did not. Nine patients excluded from the study. The BMD in the second metacarpals and serum indices of bone metabolism were determined. BMD on the hemiplegic side increased by 4.3% in the MK-4 group and decreased by 4.7% in the untreated group (p < 0.0001), while BMD on the intact side decreased by 0.9% in the MK-4 group and by 2.7% in the untreated group (p < 0.0001). At baseline, patients of both groups showed vitamin D and K1 deficiencies, high serum levels of ionized calcium, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), and low levels of parathyroid hormones (PTH) and bone Gla proteins (BGP), indicating that immobilization-induced hypercalcemia inhibits renal synthesis of 1, 25-dihydroxyvitamin D (1, 25-[OH]2D) and compensatory PTH secretion. Both vitamins K1 and K2 increased by 97.6% and 666.9%, respectively, in the MK-4 group. Correspondingly, a significant increase in BGP and decreases in both ICTP and calcium were observed in the MK-4 group, in association with a simultaneous increase in both PTH and 1, 25-[OH]2D. One patient in the untreated group suffered from a hip fracture, compared with none in the MK-4 group. The treatment with MK-4 can increase the BMD of disused and vitamin D- and K-deficient hemiplegic bone by increasing the vitamin K concentration, and it also can decrease calcium levels through inhibition of bone resorption, resulting in an increase in 1, 25-[OH]2D concentration. (Bone 23:291–296; 1998) © 1998 by Elsevier Science Inc. All rights reserved.
In a previous study we found that four factors figure significantly in the reduced bone mineral density (BMD) on the hemiplegic side compared with the contralateral side in patients following a stroke:22–26 (1) disuse due to paralysis, (2) vitamin D deficiency due to malnutrition, sunlight deprivation, and immobilizationinduced hypercalcemia, (3) compensatory hyperparathyroidism, and (4) vitamin K deficiency due to malnutrition. We also showed that a 1.0 mg daily dose of alfacalcidol (an active form of vitamin D3) can reduce the risk of hip fractures frequently occurring on the hemiplegic side in this population, and can prevent a further decrease in BMD on the hemiplegic side of patients with a long-standing stroke.27 Since Bouckaert and Said first reported the effect of vitamin K on fracture healing in 1960, several studies have suggested that this vitamin affects bone metabolism. Vitamin K is essential to site-specific carboxylation of bone Gla protein (BGP) and other bone matrix proteins.28,33 As a biochemical indicator of compromised vitamin K status, reduced serum BGP concentration has been associated with a reduced bone mineral density (BMD) at the hip32 and increased risk of fracture31 in otherwise healthy adults. In patients who had sustained fractures, especially at the hip, serum vitamin K concentrations have been found to be lower than in age-matched controls.4,10 –12 It has been demonstrated that treatment with vitamin K2 (menatetrenone; menaquinone-4; MK-4) is more effective in increasing BMD than alfacalcidol in involutional osteoporosis.19 We conducted a 12-month randomized trial to evaluate the efficacy of menatetrenone in reducing the severity of the osteopenia in the second metacarpals and in decreasing the risk of hip fractures in stroke patients with hemiplegia. Materials and Methods For this study we selected 108 outpatients with hemiplegia following strokes who had been examined at the Futase Social Insurance Hospital. All had suffered a stroke within the preceding 2 years. We determined the body mass index (BMI) and Barthel index (BI)14; the latter is a functional dependence score in which a score of 100 represents independence, while a score of 0 represents total independence. Clinical severity of the hemiplegia was evaluated using Brunstrom’s staging classification,5 in which a score of 1 is defined as paralysis of the fingers and leg, while a score of 6 represents normal strength. The diagnosis of the stroke was based on the results of clinical evaluation, including mode of onset, neurological examination, and computed tomography (CT) scans performed in the acute
Key Words: Hemiplegia; Menatetrenone; Osteopenia; Stroke; Vitamin D; Vitamin K.
Address for correspondence and reprints: Dr. Yoshihiro Sato, Department of Neurology, Kurume University Medical Center, 155-1 Kokubumachi, Kurume 839-0863, Japan. E-mail: [email protected] © 1998 by Elsevier Science Inc. All rights reserved.
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and chronic phases of the disorder. The strokes were classified according to the Classification of Cerebrovascular Diseases III of the National Institute of Neurological Disorders and Stroke.29 Patients with strokes were excluded if they showed other known causes of osteoporosis, such as hyperparathyroidism or renal osteodystrophy, and impairment of hepatic, renal, cardiac, or thyroid function. Also excluded were patients with a history of therapy with warfarin, corticosteroids, estrogens, calcitonin, etidronate, calcium, vitamin D, or anticonvulsants for 3 months or longer during the 12 months preceding the study. If therapy of this nature occurred during the 2 months immediately preceding the study, even brief treatment was cause for exclusion. Thirtyfive age-matched volunteers (17 men and 18 women) served as healthy controls. The study was approved by the institutional ethics committee, and informed consent was obtained from all study subjects in the presence of a witness. The patients were randomly assigned either to the menatetrenone (n 5 54) or the untreated (n 5 54) group. No placebo capsules were administered. Menatetrenone at a daily dose of 45 mg/day was given to the treatment group. No dose adjustments were made at any time in the study. The two groups were observed for 12 months of treatment. The patients’ clinical status was assessed at baseline and followed up every 2 weeks, at which times clinical status was assessed, and hip fractures were recorded. Three patients in the treatment group and six in the untreatment group dropped out or withdrew from the study due to noncompliance, loss to followup, or intercurrent illness. Thus, a total of 99 patients (51 in the treatment group and 48 patients in the untreated group) completed the trial. The starting and final data for the subjects were analyzed. Medical and bone evaluations performed before randomization were used for the determination of baseline values. Using a computed X-ray densitometer (CXD; Teijin, Tokyo),16 the BMD of the second metacarpal was measured in both hands. The CXD method measures bone density at the middle of the second metacarpal using a radiograph of the hand relative to an aluminum step wedge used as a standard (20 steps, 1 mm/ step). The computer algorithm compares bone radiodensity with the gradations of the aluminum step wedge, calculating bone thickness as an aluminum equivalent (mm Al) with the same X-ray absorption. On the day of bone evaluation, a fasting blood sample was obtained in 54 patients taking menatetrenone, 54 patients without treatment, and 35 healthy controls. Blood samples were analyzed for vitamins K1 and K2, intact parathyroid hormone (PTH), ionized calcium, intact BGP, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), 25-hydroxyvitamin D (25-OHD), 1, 25-dihydroxyvitamin D (1, 25-[OH]2D), and albumin. Circulating levels of vitamin K including vitamin K1 (phylloquinone) and vitamin K2 (menaquinone-4; MK 4) were measured by high-performance liquid chromatography according to the method of Langenberg and Tjaden.13 When vitamin K2 was undetectable, attempts were made to detect it in the concentrated serum. Serum PTH was measured by a radioimmunoassay (RIA; Nichols Institute Diagnostics, San Juan Capistrano, CA; normal range for control individuals in our laboratory, 19 –54 pg/mL). Ionized calcium in serum prepared freshly under anaerobic conditions was measured using an ion-selective electrode and an ionized calcium analyzer (NOVA Biochemical, Newton, MA; normal range 2.313–2.515 mEq/L). Intact BGP was measured with an established enzyme immunoassay using antibodies to Nand C-terminal regions of human BGP (Teijin Diagnostics, Tokyo; normal range 6.6 –15.4 ng/mL). ICTP was measured by RIA (Orion Diagnostica, Oulunsalo, Finland; normal range 2.0 –
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3.2 ng/mL). Serum 25-OHD was determined using a competitive protein-binding assay, and 1, 25-[OH]2D was determined by a radioreceptor assay using a calf thymus receptor (Nichols Institute Diagnostics). Sunlight exposure during the preceding year was assessed by a questionnaire administered to patients or family members, and was graded as either almost none (less than 15 min per week) or longer. Additionally, the mean weekly dietary vitamin D intake was estimated for each individual. All statistical procedures were performed using the Statview 4.11 software packages (Abacus Concepts, Berkeley, CA). Data are presented as the mean 6 standard deviation (SD). One-way analysis of variance (ANOVA) and Fisher’s protected least significant difference were used to assess baseline differences between three groups. Group differences of the categorical data were tested by x2 analyses. The paired t-test was used to assess the significance of the differences of BMDs between intact and hemiplegic sides. To examine a possible correlation between BMD on both sides and vitamins K, BGP, 25-OHD, and ionized calcium concentrations and the degree of paralysis, or BI, between serum calcium level and BI and 1, 25-[OH]2D concentration, and between PTH and 25-OHD, Spearman’s rank correlation coefficients (SRCC) were calculated. To examine the correlation between vitamin D metabolite levels and albumin, SRCC was calculated between the 1, 25-[OH]2D concentration and albumin. Correlations (SRCC) of ionized calcium, ICTP, and BGP with duration of illness were also calculated. For BMD measurements individual values and laboratory values were computed and expressed as a percent change from the baseline. The two groups were then compared with respect to BMD and the laboratory values by using the Wilcoxon rank sum test. The difference of hip fracture rate between the two groups for 12 months was tested by Fisher’s exact test. p values of less than 5% were considered statistically significant. Results Baseline Characteristics of Study Subjects (Tables 1 and 2) Demographic and baseline clinical features of study patients and healthy control are presented in Tables 1 and 2. The three groups showed identical composition with respect to age and gender. There were also no significant differences between the two patient groups in duration of illness, BI, degree of hemiplegia, BMI, type of stroke, BMD, and serum indices of bone metabolism. At the baseline, the BMDs on the hemiplegic side were significantly lower than those on the intact side and those of the controls, as also observed in previous studies.22–27 Also, in the two patient groups, the baseline values of serum vitamin K1, PTH, BGP, albumin, and 25-OHD concentrations were low, and the value of 1, 25-[OH]2D was at a level of low normal, while the value of serum K2 was normal. The value for ionized calcium was elevated in 40 patients (74%) of the untreated group and in 41 patients (76%) of the treated group. The ICTP value was high in 47 untreated patients (87%) and in 48 treated patients (89%). Reduced mobility with a mean BI of 78 –79 prevented the patients from venturing outdoors, and 83 (84%) of 99 patients had been exposed to sunlight for less than 15 min per week; 76 patients (77%) consumed less vitamin D than the Japanese recommended daily allowance (100 IU). BMI were significantly lower in patients than in control subjects. All 46 female patients were postmenopausal. BMD values were significantly lower in females than in males: 1.899 6 0.465 vs. 2.312 6 0.385 on the hemiplegic side (p , 0.0001); 2.110 6 0.392 vs. 2.484 6 0.342 on the contralateral side (p , 0.0001) in both treated and untreated groups. No differences were observed
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Table 1. Demographic and baseline clinical charact eristics of control subjects and hemiplegic patients with stroke at study entry
Characteristic Age (years) Gender (M/F) Duration of illness (months)c Body mass index (kg/m2) Barthel index Degree of hemiplegia Finger Leg Type of stroke (bleeding/infarction) Sunlight exposure 15 min . (%) 15 min , or none (%) Dietary intake of vitamin D Less than 100 IU (%)
Control (n 5 35)
Untreated (n 5 54)
Menatetrenone-treated (n 5 54)
p value
66.8 6 6.1 17/18 22.9 6 1.8 -
65.6 6 7.3 23/31 13.2 6 7.8 19.4 6 1.8b 78 6 28
66.3 6 6.0 25/29 13.9 6 6.4 19.9 6 1.7b 79 6 27
0.69a 0.70 0.88 ,0.0001a 0.81
-
3.1 6 1.8 4.4 6 1.3
3.0 6 1.6 4.2 6 1.2
0.82 0.52
-
19/35
17/37
0.68
33 (94) 2 (6)
9 (17) 45 (83)
7 (13) 47 (87)
0.59
2 (6)
36 (67)
38 (70)
0.68
a
ANOVA. p , 0.0001 vs. controls. As the day the patient first experienced hemiplegia was defined as the onset of stroke, the duration of illness was defined as the duration of both hemiplegia and stroke in the two groups. b c
between male and female patients in age, duration of illness, BI, degree of finger paralysis, or BMI. No significant gender-related differences were noted in serum concentrations of K1, K2, PTH, ionized calcium, BGP, ICTP, 25-OHD, 1, 25-[OH]2D, or albumin. When the treated and untreated patients were analyzed together, the BMD on the hemiplegic side correlated positively with K1 (r 5 0.290, p 5 0.0041), BGP (r 5 0.311, p 5 0.0012), 25-OHD (r 5 0.436, p , 0.0001), and calcium (r 5 20.290, p 5 0.0041) concentrations, degree of finger paralysis (r 5 0.264, p 5 0.0088), and with BI (r 5 0.205, p 5 0.0426). On the intact side, BMD correlated only with 25-OHD (r 5 0.324, p 5 0.0003). There were correlations between the serum ionized calcium level and BI (r 5 20.362, p 5 0.0002), ICTP (r 5 0.358, p 5 0.0004), or the 1, 25-[OH]2D (r 5 20.318, p 5 0.0016) concentrations. The BI score correlated with ICTP (r 5 20.248, p 5 0.0140). No correlation between the serum level of PTH and 25-OHD concentrations was observed (p 5 0.91), indicating that compensatory hyperparathyroidism did not occur.
A positive correlation between 1, 25-[OH]2D and albumin levels was observed (r 5 0.257, p 5 0.0108), indicating a low level of the vitamin D binding protein (not determined in the present study) was also responsible for hypovitaminosis D. Duration of illness correlated negatively with ionized calcium (r 5 20.215, p 5 0.0350) and ICTP (r 5 0.273, p 5 0.0075), but not with BGP (r 5 20.052, p 5 0.61). Bone Changes and Serum Biochemical Markers (Table 3) Percent changes in BMD on the hemiplegic side were 14.3 6 9.9 in the menatetrenone group and 24.7 6 7.6 in the untreated group. On the nonhemiplegic side, percent changes in BMD were 20.9 6 3.6 in the treated group and 22.7 6 2.9 in the untreated group. The differences of changes of BMD on both sides between the menatetrenone-treated group and the untreated group were statistically significant (p , 0.0001 and p 5 0.0011). During the 12-month study period, not only K2 but also K1 increased significantly in the menatetrenone-treated group but
Table 2. Bone mineral density and various serum biochemical tests of control subjects and two groups of stroke patients at baseline
Bone mineral density (mm Al) Hemiplegic side Intact side Ionized calcium (mEq/L) Parathyroid hormone (pg/mL) Albumin (g/dL) Vitamin K1 (ng/mL) Vitamin K2 (ng/mL) 25-OHD (ng/mL) 1, 25-[OH]2D (pg/mL) Intact BGP (ng/mL) ICTP (ng/mL)
Control
Untreated
Menatetrenone-treated
p valuea
2.854 6 0.423 2.885 6 0.426 2.414 6 0.101 35 6 16 4.5 6 0.3 0.562 6 0.682 0.073 6 0.165 21.6 6 3.1 49.6 6 9.4 11.0 6 4.4 2.6 6 0.6
2.109 6 0.407b,c 2.327 6 0.248b 2.584 6 0.070b 28 6 15d 3.8 6 0.5b 0.226 6 0.081b 0.087 6 0.201 9.8 6 3.2b 23.6 6 6.8b 3.5 6 2.4b 8.8 6 2.7b
2.130 6 0.635b,c 2.294 6 0.558b 2.585 6 0.107b 26 6 11d 3.9 6 0.3b 0.215 6 0.089b 0.084 6 0.182 9.7 6 3.5b 23.8 6 10.8b 3.7 6 1.9b 8.6 6 3.7b
,0.0001 ,0.0001 ,0.0001 0.020 ,0.0001 ,0.0001 0.96 ,0.0001 ,0.0001 ,0.0001 ,0.0001
Values are mean 6 SD. ANOVA. p , 0.0001 vs. controls. c p , 0.0001 vs. intact side. d p , 0.05 vs. controls. 25-OHD 5 25-hydroxyvitamin D; 1, 25-[OH]2D 5 1, 25-dihydroxyvitamin D; BGP 5 bone Gla protein; ICTP 5 pyridinoline cross-linked carboxyterminal telopeptide of type I collagen. a
b
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Table 3. Bone mineral density and laboratory values and changes of 99 subjects who completed study Percent change after 12 months followup (values at 12 months)
Bone mineral density (mm Al) Hemiplegic side Intact side Ionized calcium (mEq/L) Intact PTH (pg/mL) Vitamin K1 (ng/mL) Vitamin K2 (ng/mL) 25-OHD (ng/mL) 1, 25-[OH]2D (pg/mL) Intact BGP (ng/mL) ICTP (ng/mL)
Untreated (n 5 48)
Menatetrenone-treated (n 5 51)
p valuea
24.7 6 7.6 (2.024 6 0.481) 22.7 6 2.9 (2.261 6 0.228) 0.4 6 1.9 (2.589 6 0.069) 4.4 6 6.3 (24 6 11) 2.4 6 4.2 (0.225 6 0.098) 21.7 6 4.2 (0.081 6 0.162) 23.3 6 2.3 (9.4 6 2.8) 21.7 6 0.6 (29.4 6 10.7) 24.6 6 3.3 (3.3 6 2.3) 22.1 6 17.4 (8.6 6 2.99)
4.3 6 9.9 (2.173 6 0.546) 20.9 6 3.6 (2.273 6 0.561) 24.2 6 6.1 (2.473 6 0.123) 70.4 6 97.4 (38 6 14) 97.6 6 29.2 (0.320 6 0.238) 669.7 6 218.3 (26.1 6 27.2) 23.5 6 1.5 (9.3 6 3.7) 16.9 6 16.5 (33.3 6 11.9) 217.5 6 126.9 (6.4 6 2.1) 232.0 6 12.6 (6.1 6 3.0)
,0.0001 ,0.0001 ,0.0001 ,0.0001 ,0.0001 ,0.0001 0.91 ,0.0001 ,0.0001 ,0.0001
Values are mean 6 SD. p 5 Wilcoxon rank sum test.
a
not in the untreated group, and no significant difference in percent changes of 25-OHD between the two groups was observed. Ionized calcium, PTH, and BGP were also increased while ICTP was decreased significantly in the menatetrenonetreated group, as compared with the untreated group. Unexpectedly, 1, 25-[OH]2D was increased significantly in the treated group as compared to the untreated group. Fracture Incidence A hip fracture occurred on the hemiplegic side of a female patient in the untreated group. No hip fractures were recorded in the menatetrenone-treated group. The incidence of hip fractures was not significantly different between the two groups (p 5 0.48; 0/50 vs. 1/48). Fractures other than of the hip were not observed in either group. Discussion In the present study we found both vitamins D and K1, BGP, the degree of paralysis, calcium levels, and BI correlated with BMD in bones affected by disuse on the hemiplegic side in stroke patients. On the nonhemiplegic side, only 25-OHD correlated with BMD. Prolonged immobilization from spinal cord injury has long been known to result in hypercalciuria, hypercalcemia, accelerated bone resorption, and osteoporosis.2,3,6,7,17,18,30 Reduction in bone formation is evidenced by diminished osteoid thickness and mineralization rates observed in biopsy specimens.17 On the other hand, in vitamin D deficiency, bone mineralization is impaired, leading to accumulation of an unmineralized matrix or osteoid in the skeleton. In the present study, immobilization-induced hypercalcemia,30 as evidenced by a negative correlation between BI and serum levels of ionized calcium, may inhibit compensatory PTH secretion and thus 1, 25-[OH]2D production. Hypercalcemiainduced inhibition of 1, 25-[OH]2D production in the kidney may result in a low normal of 1, 25-[OH]2D. Both disuse-affected and vitamin D-deficient bone must be present on the hemiplegic side in the patients studied here. Serum BGP was depressed in patients and correlated well with the decrease in BMD in spite of the presence of hypovitaminosis D with an increased level of ICTP in the present study. This is explained by the two mechanisms. First, low vitamin K stores result in the reduction of BGP carboxylation. Second,
hypercalcemia inhibits the production of 1, 25-[OH]2D, resulting in subnormal vitamin D levels. 1, 25-[OH]2D is needed to enhance the synthesis of osteoblast-derived BGP and matrix BGP.8,20 Thus, BGP production is reduced when both vitamin K and 1, 25-[OH]2D concentrations are low as in the present state, representing a combination of disuse and osteomalacia, which may account for the close correlation between lowered BMD and decreased BGP concentration. On the other hand, an increased level of ICTP observed in many patients in both groups implies increased bone resorption due to immobilization, because there was a close correlation between ICTP and BI. Also, because illness duration correlated negatively with ionized calcium and ICTP, a high rate of bone resorption may occur during the early stages of a stroke. Because calcium was correlated with both BI and ICTP, immobilization hypercalcemia would be the reflection of increased bone resorption. The vitamin K1 deficiency in the patient groups was considered to reflect generally poor nutrition, as evidenced by low serum concentrations of 25-OHD and albumin. Treatment with menatetrenone is more effective than alfacalcidol in increasing BMD in involutional osteoporosis.19 For 6 months, the BMD of metacarpal bone, measured by the microdensitometric method, increased to 1.28% 6 1.52% in patients treated with menatetrenone and decreased to 23.85% 6 2.21% in the untreated group. Also, in a study19 that compared the effect of menatetrenone at a daily dose of 45 mg of K2 with that of 1 mg of alfacalcidol for 48 weeks, metacarpal BMD was found to be increased to 2.05% 6 1.05% in the menatetrenone-treated group while it decreased by 22.42% 6 1.23% in the alfacalcidol-treated group. The routine use of menatetrenone (45 mg/day) in patients with poststroke hemiplegia may be beneficial for several reasons, as suggested by this study. First, BMD on the hemiplegic side increased by 4.3% 6 9.9% in the treated group and decreased 4.7% 6 7.6% in the untreated group (p , 0.0001), while BMD on the intact side decreased by 0.9% 6 3.6% in the treated group and by 2.7% 6 2.9% in untreated groups (p 5 0.0011). Second, menatetrenone significantly increased serum concentrations of vitamin K, not only K2 but also K1. Orally administered K1 is partially transformed into MK-4,21 but a converse transformation has not been observed. Although the precise reason in unknown, administration of a daily dose of 45 mg of vitamin K2 may result in an increase of serum concentration of vitamin K1. Finally, improvement of hypercalcemia by the treatment re-
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sulted in increased serum concentrations of PTH, 1, 25-[OH]2D, and thus BGP. Increased BGP by treatment was attributed to increased vitamin D and K and to release from inhibited compensatory hyperparathyroidism. Conversely, decreased ICTP after the treatment may be due to the inhibitory effect of menatetrenone itself on bone resorption. Indeed, menatetrenone inhibits bone resorption through inhibition of prostaglandin E2 synthesis in vitro9 and has inhibitory effects on osteoclast-like cell formation in mouse bone marrow cultures.1 Menatetrenone increased BMD on the hemiplegic side, but decreased it on the nonhemiplegic side. Our previous study of 1 mg of alfacalcidol on poststroke hemiplegia demonstrated that BMD on the hemiplegic side decreased by 2.4% in the treatment group and 8.9% in the placebo group (p 5 0.0021), while BMD on the intact side increased by 3.5% and decreased by 6.3% in the treated and placebo groups, respectively (p 5 0.0177).27 Some explanations could account for the discrepancy of the effects between the two agents. The causes of osteopenia may be different between the hemiplegic and intact sides; BMD on the hemiplegic side correlated with vitamins D and K1, BGP, degree of paralysis, calcium, and BI, while BMD on the intact side correlated with vitamin D only. Menatetrenone might increase BMD of the disused hemiplegic limb by increasing vitamins D and K, leading to an increase in bone formation and an inhibition of bone resorption, while it acts on the BMD of the intact side by increasing vitamin D. Administration of menatetrenone to ischemic stroke patients may cause a hypercoagulable state, resulting in increased risk of a secondary ischemic stroke. We evaluated the risk of secondary ischemic stroke in 156 patients with cerebral infarction by administration of a daily dose of 45 mg menatetrenone over a 1.5 year period, and a secondary stroke or myocardial infarction did not occur in any patients (unpublished data, Sato, 1998). Thus, a daily dose of 45 mg menatetrenone may be not harmful to ischemic stroke patients. Metacarpal CXD observations have been validated and found to be generalizable by comparison between metacarpal BMD determined by CXD and vertebral (L2– 4), femoral neck, and overall BMD measurements performed by the better known but less available method of dual-energy X-ray absorptiometry.15 Therefore, the reduction in second metacarpal BMD in stroke patients may reflect a generalized decrease of BMD throughout the skeleton. One hip fracture was observed in the untreated group, while such a fracture did not occur in the treatment group. Although there was no statistically significant difference in the incidence of the fractures between the two groups, the treatment with menatetrenone might reduce the risk of hip fractures in stroke patients with hemiplegia, probably by increasing the BMD of the femoral neck. References 1. Akiyama, Y., Hara, K., Tajima, T., Murota, S., and Morita, I. Effects of vitamin K2 (menatetrenone) on osteoclast-like cell formation in mouse bone marrow cultures. Eur J Pharmacol 263:181–185; 1994. 2. Bergmann, P., Heilporn, A., Schoutens, A., Paternot, J., and Tricot, A. Longitudinal study of calcium and bone metabolism in paraplegic patients. Paraplegia 15:147–159; 1997. 3. Biering-Sørensen, F., Bohr, H. H., and Schaadt, O. P. Longitudinal study of bone mineral content in the lumbar spine, the forearm and the lower extremities after spinal cord injury. Eur J Clin Invest 20:330 –335; 1990. 4. Bitensky, L., Hart, J. P., Catterrall, A., Hodges, S. J., Pilkington, M. J., and Chayen, J. Circulating vitamin K levels in patients with fractures. J Bone Joint Surg 70B:663– 662; 1988. 5. Brunstrom, S. Motor testing procedures in hemiplegia. Based on sequential recovery stages. Am J Phys Ther 46:357–375; 1966.
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Date Received: March 10, 1998 Date Revised: May 6, 1998 Date Accepted: May 11, 1998