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Lack of effect of a single oral dose of cyclosporine on systemic blood pressure and on forearm blood flow and vascular resistance in humans
AJH
1998;11:1371–1375
BRIEF COMMUNICATIONS
Lack of Effect of a Single Oral Dose of Cyclosporine on Systemic Blood Pressure and on Forearm Blood Flow and Vascular Resistance in Humans Jose´ Jayme Galva˜o De Lima, Fernanda M. Consolim Colombo, Heno Ferreira Lopes, Grazia Maria Guerra Riccio, and Eduardo M. Krieger
The acute hemodynamic effect of cyclosporine in man is controversial. A randomized, double blind, placebo-controlled, cross-over study was undertaken to evaluate the effect of a single oral dose of cyclosporine (20 mg/kg body weight) on mean blood pressure (MBP), heart rate (HR), forearm blood flow (FBF), and vascular resistance (FVR) in 16 healthy adult subjects. Subjects were studied twice, with an intervening period of 2 weeks, before and after the administration of either cyclosporine or the vehicle olive oil. Blood pressure was measured on brachial and digital arteries. After 30 min of rest, basal measurements were obtained and individuals were randomly assigned to receive either cyclosporine or the vehicle, and the same measurements were repeated 2 h later. Mean whole blood levels of cyclosporine were 1542 6 387 ng/mL (range 1000 to 2550) 2 h after the administration of a single oral dose of cyclosporine. Cyclosporine did not cause any significant change in the hemodynamic parameters
C
when compared with vehicle. Pre- and post– cyclosporine data were as follows (means 6 SD): MBP (determined by Finapres on the digital artery), 92 6 10 v 95 6 11 mm Hg; HR, 66 6 10 v 68 6 11 beats/min; FBF, 3.9 6 1.3 v 3.8 6 1.8 mL/ 100 mL/min; and FVR, 28 6 9 v 33 6 18 units, respectively. For the vehicle the results were: MBP, 94 6 9 v 94 6 9; HR, 67 6 9 v 67 6 11; FBF, 3.3 6 1.6 v 3.2 6 2.0; FVR, 35 6 14 v 37 6 15, respectively. These figures did not differ from those obtained with the auscultatory method applied to the brachial artery among 10 selected subjects studied with Finapres. In conclusion, we found no evidence that at supratherapeutic doses cyclosporine causes acute increase in blood pressure or peripheral vasoconstriction in humans. Am J Hypertens 1998;11:1371–1375 © 1998 American Journal of Hypertension, Ltd. KEY WORDS:
cyclosporine, forearm blood flow, forearm vascular resistance, blood pressure.
yclosporine, an immunosuppressive drug widely used in organ transplantation, increases arterial blood pressure in humans and in various animal species. In humans, hypertension is a common complication of chronic cyclosporine administration and is believed to be
caused mainly by sodium and water retention due to reduction of renal plasma flow and glomerular filtration rate.1,2 There are few investigations on the acute hemodynamic effect of cyclosporine in man. Sturrock et al3 studied the effect of acute administration of cyclosporine on arterial blood pressure in normal vol-
Received August 26, 1997. Accepted June 12, 1998. From the Hypertension Unit, Heart Institute, Sa˜o Paulo University Medical School, Sa˜o Paulo, Brazil. This study was supported by the E.J. Zerbini Foundation, Sa˜o Paulo, Brazil.
Address correspondence and reprint requests to Jose´ Jayme Galva˜o De Lima, MD, Unidade de Hipertensa˜o, Instituto do Corac¸a˜o, Rua Ene´as C. Aguiar, 44, 05403-000 Sa˜o Paulo SP Brazil.
© 1998 by the American Journal of Hypertension, Ltd. Published by Elsevier Science, Inc.
0895-7061/98/$19.00 PII S0895-7061(98)00156-3
1372
˜ O DE LIMA ET AL GALVA
unteers. They found that blood pressure was increased independently of changes in renal function or in sodium excretion, suggesting that the systemic hemodynamic and the renal effects of cyclosporine are initially dissociated. More recently, Hansen et al4 also documented a significant elevation of mean blood pressure in humans receiving a single oral dose of a different cyclosporine formulation (Samdimum Neoral, Sandoz, Basel, Switzerland). Other authors, however, found no significant changes in blood pressure after oral administration5,6 or during intravenous infusion7 of cyclosporine. A better definition of the initial hemodynamic change induced by cyclosporine is important because it may be the primary cause of other complex alterations observed with chronic use of the drug. To perform a more comprehensive analysis of the acute hemodynamic actions of cyclosporine in man, we conducted a double blind, placebo-controlled, randomized, cross-over study that included determinations of arterial blood pressure, forearm blood flow, and vascular resistance by plethysmography, before and after a single oral dose of cyclosporine. As the discordant results in the literature could be caused by differences in methods applied to measure arterial blood pressure, we simultaneously determined this parameter on the brachial and digital arteries using noninvasive methodologies. METHODS Subjects The study group consisted of 16 healthy volunteers (10 men and 6 women) ranging in age from 21 to 61 years (mean 37.6 6 12.4). There were 14 whites, one black, and one Oriental. The subjects were not taking medications and were ingesting unrestricted diets. Medical history, physical examination, and routine laboratory tests (including electrocardiogram [EKG], echocardiogram, chest x-ray, serum glucose and lipids, urinalysis, and endogenous creatinine clearance) were all negative or within normal limits. Mean body weight was 64.2 6 10.2 kg (range 48.0 to 80.0). Written informed consent was obtained from all participants. The experimental protocol was approved by the institutional committee for human research. Procedures Studies were conducted in a quiet room with a temperature of 22°C to 25°C with the individuals in the supine position. The room was free of noise and the lights were dimmed. Alcohol, caffeine, and cigarettes were all forbidden 12 h before the study. Systolic and diastolic blood pressures were continuously determined with a Finapres apparatus (Ohmeda 2300, Englewood, CO) attached to the left third finger and recorded on a multichannel polygraph.8 Blood pressure was also measured on the brachial artery by the auscultatory method (mean of three determinations at interval of 1 min) determined at the
AJH–NOVEMBER 1998 –VOL. 11, NO. 11, PART 1
initiation of each experimental period in 10 selected individuals. Heart rate was obtained from the blood pressure tracings, and mean blood pressure was calculated from diastolic blood pressure plus one third of the pulse pressure (auscultotory method). Blood flow determinations were performed with a calibrated mercury-in-Sylastic strain gauge and expressed as milliliters per 100 mL of forearm volume per minute,9 using a Hokanson model EC-4 instrument (D.E. Hokanson, Inc., Issaquah, WA). The gauge was applied on the right arm, 5 cm below the antecubital crease, while the arm was supported above heart level. The venous occlusion pressure was 35 mm Hg, and circulation to the hand was prevented by inflating a wrist cuff to suprasystolic pressure for 1 min before forearm blood flow determination. Forearm vascular resistance was calculated as mean blood pressure/forearm blood flow and expressed as resistance units. Forearm vascular resistance was calculated using mean blood pressure values obtained by Finapres and also by the auscultatory method in 10 subjects. Each blood pressure (recorded by Finapres), heart rate, forearm blood flow, and vascular resistance value represents the average of all determinations obtained over a period of 5 min. Ten to 15 forearm blood flow determinations were recorded during each period of observation. Protocol The present study was a randomized, double blind, placebo-controlled, cross-over investigation. The investigations were conducted between 9:00 and 10:00 am. Data collection was initiated after a resting period of 30 to 40 min. Following baseline measurements of systolic and diastolic blood pressure, heart rate, and forearm blood flow, subjects were asked to ingest either cyclosporine (Sandimun oral solution, Sandoz Pharmaceuticals, Basel, Switzerland) at the dose of 20 mg/kg or equal volume of the vehicle. Cyclosporine solution and olive oil were blended with 200 mL of milk before administration. The same measurements were repeated 2 h after drug administration. This time interval was chosen for two reasons: first, it is associated with maximum blood levels of cyclosporine after a single oral dose similar to that employed here3; second, during this interval there are no changes in renal hemodynamics likely to influence blood pressure, contrary to what is frequently observed during later periods.4 –7 Cyclosporine levels in blood were determined at the conclusion of the study by radioimmunoassay (Incstar Corporation, Stillwater, MN). After 2 weeks, the studies were repeated inverting the drug administered (cyclosporine or vehicle). The order of the drug administration was randomly determined by a computer-generated list that was known only to a registered nurse who was also appointed to prepare the milk-cyclosporine or olive oil blend. Subjects and investigators were unaware of the
AJH–NOVEMBER 1998 –VOL. 11, NO. 11, PART 1
HEMODYNAMIC EFFECTS OF CYCLOSPORINE IN HUMANS
1373
TABLE 1. SYSTOLIC, DIASTOLIC, AND MEAN BLOOD PRESSURE, HEART RATE AND FOREARM BLOOD FLOW AND VASCULAR RESISTANCE BEFORE AND AFTER A SINGLE ORAL DOSE OF CYCLOSPORINE OR THE VEHICLE OLIVE OIL (MEAN 6 SD) Cyclosporin
SBP, mm Hg (F) DBP, mm Hg (F) MBP, mm Hg (F) HR, beats/min FBF, mL/100 mL/min FVR, units (F) SBP, mm Hg (A) DBP, mm Hg (A) MBP, mm Hg (A) FVR, units (A)
Olive Oil
Basal
Postdrug
Basal
Postdrug
137 6 15 72 6 7 94 6 8 67 6 12 3.7 6 1.2 28.7 6 8.5 123 6 13 83 6 8 96 6 9 28 6 8
137 6 15 74 6 9 96 6 10 69 6 13 3.9 6 2.1 33.3 6 19.5 131 6 15 81 6 7 99 6 8 33 6 18
136 6 12 73 6 8 94 6 7 67 6 10 3.3 6 1.6 34.1 6 12.8 125 6 8 77 6 7 93 6 7 33 6 12
135 6 13 71 6 7 92 6 7 68 6 13 3.0 6 2.2 39.2 6 14.3 126 6 13 79 6 7 95 6 8 39 6 14
SBP, systolic blood pressure; DBP, diastolic blood pressure; MBP, mean blood pressure; HR, heart rate; FBF, forearm blood flow; FVR, forearm vascular resistance; F, finapress; A, auscultatory.
sequence of drug administration up to the conclusion of the data analysis. The tracings were analyzed by two investigators in a blind manner. Interobserver discrepancies were ,10%. Statistical Analysis Values are expressed as means 6 SD. Comparisons were performed between the percentage variation from post- in relation to predrug values. For each variable, the carry-over effect was evaluated and, if significant, one factor ANOVA was performed for the first period to evaluate the drug effect. In case of no carry-over effect, overall drug effect was tested by means of cross-over specific ANOVA.10 A value of P , .05 was considered statistically significant. Operations were performed using a SAS statistical package. RESULTS Mean whole-blood levels of cyclosporine were 1542 6 387 ng/mL (range 1000 to 2550) 2 h after the admin-
istration of a single oral dose of cyclosporine. Blood levels of cyclosporine were undetectable after vehicle administration. Tables 1 and 2 and Figure 1 show the effects of either cyclosporine or vehicle on mean blood pressure, heart rate, and forearm blood flow and forearm vascular resistance. None of these variables were significantly changed by cyclosporine or by the vehicle. Compared with vehicle, cyclosporine ingestion was associated with a 4% increase in mean blood pressure (as determined by Finapres), 2.6% increase in heart rate, 1.4% reduction in blood flow, and 7.7% increase in vascular resistance (Table 2). These differences were not significant. Nonsignificant differences were also registered when blood pressure was determined by the auscultatory method (Table 2). The order of administration of the drugs (cyclosporine or vehicle) also did not affect blood pressure, heart rate, forearm blood flow, or forearm vascular resistance.
TABLE 2. MEAN BLOOD PRESSURE, HEART RATE, AND FOREARM BLOOD FLOW AND FOREARM VASCULAR RESISTANCE PERCENTAGE VARIATION AFTER A SINGLE ORAL DOSE OF CYCLOSPORINE OR THE VEHICLE OLIVE OIL (MEAN, SD, MINIMUM AND MAXIMUM VALUES, AND CHANGE RELATIVE TO VEHICLE) Cyclosporin
Olive Oil
Variable
Mean
SD
Min
Max
Mean
SD
Min
Max
D Change
MBP (F) HR FBF FVR (F) MBP (A) FVR (A)
3.52 3.5 0.6 19.3 2.4 22.7
9.7 8.5 49.3 50.0 6.9 56.0
210.6 14.0 253.4 261.2 27.7 264.6
26.4 20.6 164 108 14.3 134
20.5 0.9 2.0 11.6 1.7 28.7
5.8 9.3 38.4 47.5 5.5 56.6
28.2 213.6 255.7 246.4 24.8 234.3
10.6 17.2 77.8 123 13.4 115
4.0 2.6 21.4 7.7 0.6 26.0
MBP, mean blood pressure (mm Hg); HR, heart rate (beats/min); FBF, forearm blood flow (mL/100 mL/min); FVR, forearm vascular resistance (units); F, Finapres; A, auscultatory method.
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˜ O DE LIMA ET AL GALVA
AJH–NOVEMBER 1998 –VOL. 11, NO. 11, PART 1
FIGURE 1. Effects of cyclosporine (20 mg/kg) and the vehicle olive oil in mean blood pressure (MBP) (determined by Finapres), heart rate (HR), forearm blood flow (FBF), and forearm vascular resistance (FVR) in 16 healthy control subjects.
DISCUSSION There is abundant evidence that prolonged use of cyclosporine causes renal vasoconstriction and hypertension in a variety of clinical situations.11–14 However, the hemodynamic consequences of acute administration of this immunosuppressive drug in humans are controversial. Humans studies on this subject are important because no animal model exactly reproduces the vascular actions of cyclosporine as it occurs in man. In the present investigation, a single oral dose of cyclosporine, sufficient to attain blood levels within the therapeutic range, did not significantly change
systemic blood pressure, heart rate, forearm blood flow, and vascular resistance in healthy control subjects. The results were consistently reproduced using both methods and sites of blood pressure determination (auscultatory on the brachial artery and Finapres monitoring on the digital artery). The latter aspect is important because the reliability of Finapres to track blood pressure during protocols in which hemodynamic parameters are subjected to frequent variations has been questioned.15 Our findings are in agreement with those reported by Weir et al,7 who did not observe modifications in blood pressure during contin-
AJH–NOVEMBER 1998 –VOL. 11, NO. 11, PART 1
HEMODYNAMIC EFFECTS OF CYCLOSPORINE IN HUMANS
uous intravenous cyclosporine infusion in healthy volunteers for a period of #6 h. Other studies5,6 also did not document changes in blood pressure after oral administration of cyclosporine. Our observations on forearm hemodynamics are consistent with those reported by Stroes et al.16 These authors found that infusion of cyclosporine into the brachial artery of normal subjects had no vasoconstrictor effect and did not alter basal forearm blood flow. In vitro studies using human vascular beds also failed to demonstrate that exposure to cyclosporine causes vasoconstriction.17 It has been suggested that the lack of a detectable acute vasoconstrictor effect of cyclosporine is caused by the simultaneous increase in nitric oxide activity, which attenuates the vascular actions of cyclosporine.16 Taken together, these observations suggest that cyclosporine does not acutely alter blood pressure and does not exhibit measurable acute peripheral vasoconstrictor properties in humans. We could not confirm the findings of Sturrock et al3 and Hanson et al,4 who observed an increase in blood pressure after a single oral dose of cyclosporine close to that used in the present investigation. The reason for this discrepancy is not clear, but it is conceivable that methodological differences played a part. In this regard, it is perhaps of importance that ours is the first double-blind, cross-over study in the literature on this subject. It is also possible that some unmeasured factor in the subjects influenced the results. For instance, we excluded from our investigation dyslipidemic subjects. However, it has been shown that hyperlipidemia impairs endothelium-dependent relaxation18 and contributes to increase vascular tone. This suggests that vessels of hyperlipidemic individuals are potentially more susceptible to the pressor effect of cyclosporine and indicates that the lipid status of the study subjects could influence, to some extend, the hemodynamic effects of the drug. Additional studies will be necessary to confirm this hypothesis. In conclusion, we found no evidence that cyclosporine, administered at therapeutic doses, acutely increases blood pressure or causes forearm vasoconstriction in normal man. Our observations indirectly support the notion that the systemic hemodynamic effects of cyclosporine in humans are mediated mainly by renal mechanisms.
2.
Luke RG: Mechanism of cyclosporine-induced hypertension. Am J Hypertens 1991;4:468 – 471.
3.
Sturrock NDC, Lang CC, Struthers AD: Cyclosporineinduced hypertension precedes renal dysfunction and sodium retention in man. J Hypertens 1993;11:1209 –1216.
4.
Hansen JM, Fogh-Anderson N, Christensen NJ, Strandgaard S: Cyclosporine-induced hypertension and decline in renal function in healthy volunteers. J Hypertens 1997;15:319 –326.
5.
Conte G, Canton AD, Sabbatini M, Napodano P, et al: Acute cyclosporine renal dysfunction reversed by dopamine infusions in healthy subjects. Kidney Int 1989; 36:1086 –1092.
6.
De Nicola L, Libetta C, Memoli B, et al: Acute renal and immunological effects of low-dose cyclosporine in humans. Nephrol Dial Transplant 1995;10:1739 –1744.
7.
Weir MR, Klassen DK, Shen SY, et al: Acute effects of intravenous cyclosporine on blood pressure, renal hemodynamics, and urine prostaglandin production of healthy humans. Transplantation 1990;49:41– 47.
8.
Boehmer RD: Continuous, real-time, noninvasive monitor of blood pressure Penaz methodology applied to the finger. J Clin Monit 1987;3:282–287.
9.
Hirsch ATH, Levenson DJ, Cuttler SS, et al: Regional vascular responses to prolonged lower body negative pressure in normal subjects. Am J Physiol 1989;257: H219 –H225.
10.
Jones B, Kenward MG: Design and Analysis of CrossOver Trials, ed 1. Chapman and Hall, London, 1989.
11.
Loughran TP, Peeg HJ, Dahlberg S, et al: Incidence of hypertension after marrow transplantation among 112 patients randomized to either cyclosporine or methotrexate as graft versus host disease prophylaxis. Br J Haematol 1985;59:547–553.
12.
Curtis JJ, Dubovsky E, Whelchel JD, et al: Cyclosporine in therapeutic doses increases renal vascular resistance. Lancet 1986;ii:477– 479.
13.
Textor SC. De novo hypertension after liver transplantation. Hypertension 1993;22:257–267.
14.
Bennett WM, DeMattos A, Meyer MM, et al: Chronic cyclosporine nephropathy: the Achilles’ heel of immunosuppressive therapy. Kidney Int 1996;50:1089 –1100.
15.
Ristuccia HL, Grossman P, Watkins LL, Lown B. Incremental bias in Finapres estimation of baseline blood pressure levels over time. Hypertension 1997;29:1039 – 1043.
16.
Stroes ESG, Lu¨scher TF, de Groot FG, et al: Cyclosporine A increases nitric oxide activity in vivo. Hypertension 1997;29:570 –575.
17.
Richards NT, Poston L, Hilton PJ. Cyclosporine A inhibits relaxation but does not induce vasoconstriction in human subcutaneous resistance vessels. J Hypertens 1990;8:159 –163.
18.
Stroes SG, Koomans HA, de Bruin TWA, Rabelink TJ. Vascular function in the forearm of hypercholesterolemic patients off and on lipid-lowering medication. Lancet 1995;346:467– 471.
ACKNOWLEDGMENTS We are grateful to Mr. Jose´ de Souza Filho for laboratory assistance. We also thank Mrs. Elettra Greene for corrections in the manuscript and Mrs. Da´lia Ballas Wajsbrot and Mrs. Rita Helena Antonelli Cardoso for statistical analysis.
REFERENCES 1.
Curtis JJ, Luke RG, Jones P, Diethelm AG: Hypertension in cyclosporine treated renal transplant recipients is sodium dependent. Am J Med 1988;85:134 –138.
1375
1998;11:1371–1375
BRIEF COMMUNICATIONS
Lack of Effect of a Single Oral Dose of Cyclosporine on Systemic Blood Pressure and on Forearm Blood Flow and Vascular Resistance in Humans Jose´ Jayme Galva˜o De Lima, Fernanda M. Consolim Colombo, Heno Ferreira Lopes, Grazia Maria Guerra Riccio, and Eduardo M. Krieger
The acute hemodynamic effect of cyclosporine in man is controversial. A randomized, double blind, placebo-controlled, cross-over study was undertaken to evaluate the effect of a single oral dose of cyclosporine (20 mg/kg body weight) on mean blood pressure (MBP), heart rate (HR), forearm blood flow (FBF), and vascular resistance (FVR) in 16 healthy adult subjects. Subjects were studied twice, with an intervening period of 2 weeks, before and after the administration of either cyclosporine or the vehicle olive oil. Blood pressure was measured on brachial and digital arteries. After 30 min of rest, basal measurements were obtained and individuals were randomly assigned to receive either cyclosporine or the vehicle, and the same measurements were repeated 2 h later. Mean whole blood levels of cyclosporine were 1542 6 387 ng/mL (range 1000 to 2550) 2 h after the administration of a single oral dose of cyclosporine. Cyclosporine did not cause any significant change in the hemodynamic parameters
C
when compared with vehicle. Pre- and post– cyclosporine data were as follows (means 6 SD): MBP (determined by Finapres on the digital artery), 92 6 10 v 95 6 11 mm Hg; HR, 66 6 10 v 68 6 11 beats/min; FBF, 3.9 6 1.3 v 3.8 6 1.8 mL/ 100 mL/min; and FVR, 28 6 9 v 33 6 18 units, respectively. For the vehicle the results were: MBP, 94 6 9 v 94 6 9; HR, 67 6 9 v 67 6 11; FBF, 3.3 6 1.6 v 3.2 6 2.0; FVR, 35 6 14 v 37 6 15, respectively. These figures did not differ from those obtained with the auscultatory method applied to the brachial artery among 10 selected subjects studied with Finapres. In conclusion, we found no evidence that at supratherapeutic doses cyclosporine causes acute increase in blood pressure or peripheral vasoconstriction in humans. Am J Hypertens 1998;11:1371–1375 © 1998 American Journal of Hypertension, Ltd. KEY WORDS:
cyclosporine, forearm blood flow, forearm vascular resistance, blood pressure.
yclosporine, an immunosuppressive drug widely used in organ transplantation, increases arterial blood pressure in humans and in various animal species. In humans, hypertension is a common complication of chronic cyclosporine administration and is believed to be
caused mainly by sodium and water retention due to reduction of renal plasma flow and glomerular filtration rate.1,2 There are few investigations on the acute hemodynamic effect of cyclosporine in man. Sturrock et al3 studied the effect of acute administration of cyclosporine on arterial blood pressure in normal vol-
Received August 26, 1997. Accepted June 12, 1998. From the Hypertension Unit, Heart Institute, Sa˜o Paulo University Medical School, Sa˜o Paulo, Brazil. This study was supported by the E.J. Zerbini Foundation, Sa˜o Paulo, Brazil.
Address correspondence and reprint requests to Jose´ Jayme Galva˜o De Lima, MD, Unidade de Hipertensa˜o, Instituto do Corac¸a˜o, Rua Ene´as C. Aguiar, 44, 05403-000 Sa˜o Paulo SP Brazil.
© 1998 by the American Journal of Hypertension, Ltd. Published by Elsevier Science, Inc.
0895-7061/98/$19.00 PII S0895-7061(98)00156-3
1372
˜ O DE LIMA ET AL GALVA
unteers. They found that blood pressure was increased independently of changes in renal function or in sodium excretion, suggesting that the systemic hemodynamic and the renal effects of cyclosporine are initially dissociated. More recently, Hansen et al4 also documented a significant elevation of mean blood pressure in humans receiving a single oral dose of a different cyclosporine formulation (Samdimum Neoral, Sandoz, Basel, Switzerland). Other authors, however, found no significant changes in blood pressure after oral administration5,6 or during intravenous infusion7 of cyclosporine. A better definition of the initial hemodynamic change induced by cyclosporine is important because it may be the primary cause of other complex alterations observed with chronic use of the drug. To perform a more comprehensive analysis of the acute hemodynamic actions of cyclosporine in man, we conducted a double blind, placebo-controlled, randomized, cross-over study that included determinations of arterial blood pressure, forearm blood flow, and vascular resistance by plethysmography, before and after a single oral dose of cyclosporine. As the discordant results in the literature could be caused by differences in methods applied to measure arterial blood pressure, we simultaneously determined this parameter on the brachial and digital arteries using noninvasive methodologies. METHODS Subjects The study group consisted of 16 healthy volunteers (10 men and 6 women) ranging in age from 21 to 61 years (mean 37.6 6 12.4). There were 14 whites, one black, and one Oriental. The subjects were not taking medications and were ingesting unrestricted diets. Medical history, physical examination, and routine laboratory tests (including electrocardiogram [EKG], echocardiogram, chest x-ray, serum glucose and lipids, urinalysis, and endogenous creatinine clearance) were all negative or within normal limits. Mean body weight was 64.2 6 10.2 kg (range 48.0 to 80.0). Written informed consent was obtained from all participants. The experimental protocol was approved by the institutional committee for human research. Procedures Studies were conducted in a quiet room with a temperature of 22°C to 25°C with the individuals in the supine position. The room was free of noise and the lights were dimmed. Alcohol, caffeine, and cigarettes were all forbidden 12 h before the study. Systolic and diastolic blood pressures were continuously determined with a Finapres apparatus (Ohmeda 2300, Englewood, CO) attached to the left third finger and recorded on a multichannel polygraph.8 Blood pressure was also measured on the brachial artery by the auscultatory method (mean of three determinations at interval of 1 min) determined at the
AJH–NOVEMBER 1998 –VOL. 11, NO. 11, PART 1
initiation of each experimental period in 10 selected individuals. Heart rate was obtained from the blood pressure tracings, and mean blood pressure was calculated from diastolic blood pressure plus one third of the pulse pressure (auscultotory method). Blood flow determinations were performed with a calibrated mercury-in-Sylastic strain gauge and expressed as milliliters per 100 mL of forearm volume per minute,9 using a Hokanson model EC-4 instrument (D.E. Hokanson, Inc., Issaquah, WA). The gauge was applied on the right arm, 5 cm below the antecubital crease, while the arm was supported above heart level. The venous occlusion pressure was 35 mm Hg, and circulation to the hand was prevented by inflating a wrist cuff to suprasystolic pressure for 1 min before forearm blood flow determination. Forearm vascular resistance was calculated as mean blood pressure/forearm blood flow and expressed as resistance units. Forearm vascular resistance was calculated using mean blood pressure values obtained by Finapres and also by the auscultatory method in 10 subjects. Each blood pressure (recorded by Finapres), heart rate, forearm blood flow, and vascular resistance value represents the average of all determinations obtained over a period of 5 min. Ten to 15 forearm blood flow determinations were recorded during each period of observation. Protocol The present study was a randomized, double blind, placebo-controlled, cross-over investigation. The investigations were conducted between 9:00 and 10:00 am. Data collection was initiated after a resting period of 30 to 40 min. Following baseline measurements of systolic and diastolic blood pressure, heart rate, and forearm blood flow, subjects were asked to ingest either cyclosporine (Sandimun oral solution, Sandoz Pharmaceuticals, Basel, Switzerland) at the dose of 20 mg/kg or equal volume of the vehicle. Cyclosporine solution and olive oil were blended with 200 mL of milk before administration. The same measurements were repeated 2 h after drug administration. This time interval was chosen for two reasons: first, it is associated with maximum blood levels of cyclosporine after a single oral dose similar to that employed here3; second, during this interval there are no changes in renal hemodynamics likely to influence blood pressure, contrary to what is frequently observed during later periods.4 –7 Cyclosporine levels in blood were determined at the conclusion of the study by radioimmunoassay (Incstar Corporation, Stillwater, MN). After 2 weeks, the studies were repeated inverting the drug administered (cyclosporine or vehicle). The order of the drug administration was randomly determined by a computer-generated list that was known only to a registered nurse who was also appointed to prepare the milk-cyclosporine or olive oil blend. Subjects and investigators were unaware of the
AJH–NOVEMBER 1998 –VOL. 11, NO. 11, PART 1
HEMODYNAMIC EFFECTS OF CYCLOSPORINE IN HUMANS
1373
TABLE 1. SYSTOLIC, DIASTOLIC, AND MEAN BLOOD PRESSURE, HEART RATE AND FOREARM BLOOD FLOW AND VASCULAR RESISTANCE BEFORE AND AFTER A SINGLE ORAL DOSE OF CYCLOSPORINE OR THE VEHICLE OLIVE OIL (MEAN 6 SD) Cyclosporin
SBP, mm Hg (F) DBP, mm Hg (F) MBP, mm Hg (F) HR, beats/min FBF, mL/100 mL/min FVR, units (F) SBP, mm Hg (A) DBP, mm Hg (A) MBP, mm Hg (A) FVR, units (A)
Olive Oil
Basal
Postdrug
Basal
Postdrug
137 6 15 72 6 7 94 6 8 67 6 12 3.7 6 1.2 28.7 6 8.5 123 6 13 83 6 8 96 6 9 28 6 8
137 6 15 74 6 9 96 6 10 69 6 13 3.9 6 2.1 33.3 6 19.5 131 6 15 81 6 7 99 6 8 33 6 18
136 6 12 73 6 8 94 6 7 67 6 10 3.3 6 1.6 34.1 6 12.8 125 6 8 77 6 7 93 6 7 33 6 12
135 6 13 71 6 7 92 6 7 68 6 13 3.0 6 2.2 39.2 6 14.3 126 6 13 79 6 7 95 6 8 39 6 14
SBP, systolic blood pressure; DBP, diastolic blood pressure; MBP, mean blood pressure; HR, heart rate; FBF, forearm blood flow; FVR, forearm vascular resistance; F, finapress; A, auscultatory.
sequence of drug administration up to the conclusion of the data analysis. The tracings were analyzed by two investigators in a blind manner. Interobserver discrepancies were ,10%. Statistical Analysis Values are expressed as means 6 SD. Comparisons were performed between the percentage variation from post- in relation to predrug values. For each variable, the carry-over effect was evaluated and, if significant, one factor ANOVA was performed for the first period to evaluate the drug effect. In case of no carry-over effect, overall drug effect was tested by means of cross-over specific ANOVA.10 A value of P , .05 was considered statistically significant. Operations were performed using a SAS statistical package. RESULTS Mean whole-blood levels of cyclosporine were 1542 6 387 ng/mL (range 1000 to 2550) 2 h after the admin-
istration of a single oral dose of cyclosporine. Blood levels of cyclosporine were undetectable after vehicle administration. Tables 1 and 2 and Figure 1 show the effects of either cyclosporine or vehicle on mean blood pressure, heart rate, and forearm blood flow and forearm vascular resistance. None of these variables were significantly changed by cyclosporine or by the vehicle. Compared with vehicle, cyclosporine ingestion was associated with a 4% increase in mean blood pressure (as determined by Finapres), 2.6% increase in heart rate, 1.4% reduction in blood flow, and 7.7% increase in vascular resistance (Table 2). These differences were not significant. Nonsignificant differences were also registered when blood pressure was determined by the auscultatory method (Table 2). The order of administration of the drugs (cyclosporine or vehicle) also did not affect blood pressure, heart rate, forearm blood flow, or forearm vascular resistance.
TABLE 2. MEAN BLOOD PRESSURE, HEART RATE, AND FOREARM BLOOD FLOW AND FOREARM VASCULAR RESISTANCE PERCENTAGE VARIATION AFTER A SINGLE ORAL DOSE OF CYCLOSPORINE OR THE VEHICLE OLIVE OIL (MEAN, SD, MINIMUM AND MAXIMUM VALUES, AND CHANGE RELATIVE TO VEHICLE) Cyclosporin
Olive Oil
Variable
Mean
SD
Min
Max
Mean
SD
Min
Max
D Change
MBP (F) HR FBF FVR (F) MBP (A) FVR (A)
3.52 3.5 0.6 19.3 2.4 22.7
9.7 8.5 49.3 50.0 6.9 56.0
210.6 14.0 253.4 261.2 27.7 264.6
26.4 20.6 164 108 14.3 134
20.5 0.9 2.0 11.6 1.7 28.7
5.8 9.3 38.4 47.5 5.5 56.6
28.2 213.6 255.7 246.4 24.8 234.3
10.6 17.2 77.8 123 13.4 115
4.0 2.6 21.4 7.7 0.6 26.0
MBP, mean blood pressure (mm Hg); HR, heart rate (beats/min); FBF, forearm blood flow (mL/100 mL/min); FVR, forearm vascular resistance (units); F, Finapres; A, auscultatory method.
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FIGURE 1. Effects of cyclosporine (20 mg/kg) and the vehicle olive oil in mean blood pressure (MBP) (determined by Finapres), heart rate (HR), forearm blood flow (FBF), and forearm vascular resistance (FVR) in 16 healthy control subjects.
DISCUSSION There is abundant evidence that prolonged use of cyclosporine causes renal vasoconstriction and hypertension in a variety of clinical situations.11–14 However, the hemodynamic consequences of acute administration of this immunosuppressive drug in humans are controversial. Humans studies on this subject are important because no animal model exactly reproduces the vascular actions of cyclosporine as it occurs in man. In the present investigation, a single oral dose of cyclosporine, sufficient to attain blood levels within the therapeutic range, did not significantly change
systemic blood pressure, heart rate, forearm blood flow, and vascular resistance in healthy control subjects. The results were consistently reproduced using both methods and sites of blood pressure determination (auscultatory on the brachial artery and Finapres monitoring on the digital artery). The latter aspect is important because the reliability of Finapres to track blood pressure during protocols in which hemodynamic parameters are subjected to frequent variations has been questioned.15 Our findings are in agreement with those reported by Weir et al,7 who did not observe modifications in blood pressure during contin-
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HEMODYNAMIC EFFECTS OF CYCLOSPORINE IN HUMANS
uous intravenous cyclosporine infusion in healthy volunteers for a period of #6 h. Other studies5,6 also did not document changes in blood pressure after oral administration of cyclosporine. Our observations on forearm hemodynamics are consistent with those reported by Stroes et al.16 These authors found that infusion of cyclosporine into the brachial artery of normal subjects had no vasoconstrictor effect and did not alter basal forearm blood flow. In vitro studies using human vascular beds also failed to demonstrate that exposure to cyclosporine causes vasoconstriction.17 It has been suggested that the lack of a detectable acute vasoconstrictor effect of cyclosporine is caused by the simultaneous increase in nitric oxide activity, which attenuates the vascular actions of cyclosporine.16 Taken together, these observations suggest that cyclosporine does not acutely alter blood pressure and does not exhibit measurable acute peripheral vasoconstrictor properties in humans. We could not confirm the findings of Sturrock et al3 and Hanson et al,4 who observed an increase in blood pressure after a single oral dose of cyclosporine close to that used in the present investigation. The reason for this discrepancy is not clear, but it is conceivable that methodological differences played a part. In this regard, it is perhaps of importance that ours is the first double-blind, cross-over study in the literature on this subject. It is also possible that some unmeasured factor in the subjects influenced the results. For instance, we excluded from our investigation dyslipidemic subjects. However, it has been shown that hyperlipidemia impairs endothelium-dependent relaxation18 and contributes to increase vascular tone. This suggests that vessels of hyperlipidemic individuals are potentially more susceptible to the pressor effect of cyclosporine and indicates that the lipid status of the study subjects could influence, to some extend, the hemodynamic effects of the drug. Additional studies will be necessary to confirm this hypothesis. In conclusion, we found no evidence that cyclosporine, administered at therapeutic doses, acutely increases blood pressure or causes forearm vasoconstriction in normal man. Our observations indirectly support the notion that the systemic hemodynamic effects of cyclosporine in humans are mediated mainly by renal mechanisms.
2.
Luke RG: Mechanism of cyclosporine-induced hypertension. Am J Hypertens 1991;4:468 – 471.
3.
Sturrock NDC, Lang CC, Struthers AD: Cyclosporineinduced hypertension precedes renal dysfunction and sodium retention in man. J Hypertens 1993;11:1209 –1216.
4.
Hansen JM, Fogh-Anderson N, Christensen NJ, Strandgaard S: Cyclosporine-induced hypertension and decline in renal function in healthy volunteers. J Hypertens 1997;15:319 –326.
5.
Conte G, Canton AD, Sabbatini M, Napodano P, et al: Acute cyclosporine renal dysfunction reversed by dopamine infusions in healthy subjects. Kidney Int 1989; 36:1086 –1092.
6.
De Nicola L, Libetta C, Memoli B, et al: Acute renal and immunological effects of low-dose cyclosporine in humans. Nephrol Dial Transplant 1995;10:1739 –1744.
7.
Weir MR, Klassen DK, Shen SY, et al: Acute effects of intravenous cyclosporine on blood pressure, renal hemodynamics, and urine prostaglandin production of healthy humans. Transplantation 1990;49:41– 47.
8.
Boehmer RD: Continuous, real-time, noninvasive monitor of blood pressure Penaz methodology applied to the finger. J Clin Monit 1987;3:282–287.
9.
Hirsch ATH, Levenson DJ, Cuttler SS, et al: Regional vascular responses to prolonged lower body negative pressure in normal subjects. Am J Physiol 1989;257: H219 –H225.
10.
Jones B, Kenward MG: Design and Analysis of CrossOver Trials, ed 1. Chapman and Hall, London, 1989.
11.
Loughran TP, Peeg HJ, Dahlberg S, et al: Incidence of hypertension after marrow transplantation among 112 patients randomized to either cyclosporine or methotrexate as graft versus host disease prophylaxis. Br J Haematol 1985;59:547–553.
12.
Curtis JJ, Dubovsky E, Whelchel JD, et al: Cyclosporine in therapeutic doses increases renal vascular resistance. Lancet 1986;ii:477– 479.
13.
Textor SC. De novo hypertension after liver transplantation. Hypertension 1993;22:257–267.
14.
Bennett WM, DeMattos A, Meyer MM, et al: Chronic cyclosporine nephropathy: the Achilles’ heel of immunosuppressive therapy. Kidney Int 1996;50:1089 –1100.
15.
Ristuccia HL, Grossman P, Watkins LL, Lown B. Incremental bias in Finapres estimation of baseline blood pressure levels over time. Hypertension 1997;29:1039 – 1043.
16.
Stroes ESG, Lu¨scher TF, de Groot FG, et al: Cyclosporine A increases nitric oxide activity in vivo. Hypertension 1997;29:570 –575.
17.
Richards NT, Poston L, Hilton PJ. Cyclosporine A inhibits relaxation but does not induce vasoconstriction in human subcutaneous resistance vessels. J Hypertens 1990;8:159 –163.
18.
Stroes SG, Koomans HA, de Bruin TWA, Rabelink TJ. Vascular function in the forearm of hypercholesterolemic patients off and on lipid-lowering medication. Lancet 1995;346:467– 471.
ACKNOWLEDGMENTS We are grateful to Mr. Jose´ de Souza Filho for laboratory assistance. We also thank Mrs. Elettra Greene for corrections in the manuscript and Mrs. Da´lia Ballas Wajsbrot and Mrs. Rita Helena Antonelli Cardoso for statistical analysis.
REFERENCES 1.
Curtis JJ, Luke RG, Jones P, Diethelm AG: Hypertension in cyclosporine treated renal transplant recipients is sodium dependent. Am J Med 1988;85:134 –138.
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