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Cerebrospinal fluid endothelin-1 in Alzheimer's disease and senile dementia of Alzheimer type
Neuropeptides (1992) 22,85-88 0 Longman GroupUK Ltd 1992
Cerebrospinal Fluid Endothelin-1 in Alzheimer’s Disease and Senile Dementia of Alzheimer Type
T. YOSHIZAWA*, H. IWAMOTO”, H. MIZUSAWA”, N. SUZUKlt, H. MATSUMOTOt and I. KANAZAWA*S *Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba City, 305, Japan. t Tsukuba Research Laboratories, Takeda Chemical Industries, Ltd., Tsukuba City, 305, Japan. *(Present address) Department of Neurology, institute of Brain Research, School of Medicine, University of Tokyo, 113, Japan. (Correspondence and reprint request to TY) Abstract-We have measured the endothelin-1 concentrations in the cerebrospinal fluid samples from 5 patients with Alzheimer’s disease (AD), 6 patients with senile dementia of Alzheimer type (SDAT) and 7 patients with other diseases without dementia (disease control: DC). The cerebrospinal fluid endothelin-1 level was significantly lower in AD than in DC. No correlation was observed between cerebrospinal fluid endothelin-1 concentration and any other factors such as age, duration from onset, systolic blood pressure, cerebrospinal fluid protein level or plasma endothelin-1 concentration in AD or SDAT. These results suggest a possible alteration of the endothelin-1 system in the central nervous system in Alzheimer’s disease.
Introduction
In human cerebrospinal fluid (CSF), there are many kinds of neuropeptides which may be derived from the CNS neurons. Recently, ET-1 was also reported to be present in the CSF samples taken from patients with subarachnoid hemorrhage, cerebral hemorrhage, cerebral infarction, major depression and healthy volunteers (6-11). It is still unknown whether the source of ET-1 in human CSF is CNS neurons or cerebral blood vessels at present. However, the presence of ET in the porcine and rat CNS suggests a role for ET-1 as a neuropeptide in the human CNS as well. Alzheimer’s disease (AD) and senile dementia of Alzheimer type (SDAT) are neurodegenerative disorders characterized by progressive dementia which
Endothelin- 1 (ET- 1) was originally characterized as a 21 -amino acid vasoconstrictor peptide from endothelial cells, with a molecular weight of 2492 (1). We have demonstrated the presence of ET-l in the porcine central nervous system (CNS) and a depolarizing action on rat spinal neurons (2-5). Especially, in porcine and rat brain, ET-1 is localized in the posterior pituitary system and may modulate neurosecretion (5). These data suggest that ET- 1 may function as a neuropeptide in the porcine and rat CNS. Date received 2 December 199 1 Date accepted 10 February 1992
85
86
NEUROPEPTIDES
occur in middle and late life. Neuropathological and neurochemical analysis disclosed the degenerations of several neurotransmitter systems including neuropeptides which may be involved in the pathogenesis of dementia. Alterations in neurotransmitter markers or neuropeptides in CSF were also reported, which may reflect the degenerations of specific neuronal systems in CNS. However, there is no information for an alteration in the CSF ET- 1 level or the CNS ET-l system in AD and SDAT. In the present study, therefore, we determined CSF ET-l concentrations in patients with AD and SDAT compared with those of disease control.
Subjects and Methods Subjects The subjects data are summari ‘zed in the Table. 11 patients with Alzheimer type dementia (ATD) and 7 patients of disease control without dementia admitted to Tsukuba university hospital (Tsukuba) or Hatsuishi hospital (Chiba) were included in this study. All patients diagnosed as ATD met NINCDWADRDA diagnostic criteria for probable Alzheimer’s disease (12). No familial cases were
Table
Case
AD-l -2 -3 -4 -5 SDAT-1 -2 -3 -4 -5 -6 DC-1 -2 -3 -4 -5 -6 -7
included. The clinical stage of ATD patients was evaluated with the criteria of Cummings and Benson (13). ATD patients were divided into the following two groups according to the age of onset. 1) Alzheimer’s disease (AD) group; 5 patients (5 women) whose onsets were before the age of 65 years. Mean age of patients + standard deviation (SD) was 64 + 8.2.2) senile dementia of Alzheimer type (SDAT) group; 6 patients (1 man and 5 women) whose onsets were after the age of 65 years. Mean age + SD was 77.5 +4.7. Disease control (DC) group included 7 non-demented patients whose mean age +_SD was 58.9 f 9.5. The mean age in AD group was not significantly different from that in DC group. However, the mean age in SDAT group was higher than that in DC and AD group (p < 0.05, unpaired t test). None of the patients took any antihypertensive drug. CSF and blood samples After informed consent was given, we obtained CSF samples by lumbar puncture around noon. Blood samples were obtained from 4 AD patients and 6 SDAT patients before lumbar puncture. Each sample was collected in a polypropylene tube containing 300 KIU/ml of aprotinin and 2 mg/dl of EDTA.
Subjects’ profile and ET- 1 concentrations in cerebrospinal fluid and plasma samples
Age (years) 55
51 64 70 74 72 75 76 78 78 86 49 50 52 56 63 70 72
ND: not determined
Duration from onset
Systolic blood pressure
CSF protein
CSF ET-I
Plasma ET-I
(mmW
(mgjdl)
@@ml)
(mddl)
37 23 51 28 34 31 30 15 32 76 19 30 30 55 64 23 36 27
0.09 0.15 0.15 0.15 0.17 0.15 0.12 0.15 0.15 0.31 0.31 0.22 0.22 0.20 0.20 0.20 0.17 0.15
1.82 ND 1.67 2.45 1.64 2.11 2.44 4.35 1.72 1.77 2.11 ND ND ND ND ND ND ND
Sex
Diagnosis
(years)
F F F F F F M F F F F F F F M F M F
Alzheimer’s disease (stage 2) Alxheimer’s disease (stage 1) Alzheimer’s disease (stage 3) Alzheimer’s disease (stage 2) Alzheimer’s disease (stage 3) Senile dementia of Alzheimer type (stage 1) Senile dementia of Alzheimer type (stage 3) Senile dementia of Alzheimer type (stage 2) Senile dementia of Alzheimer type (stage 3) Senile dementia of Alzheimer type (stage 3) Senile dementia of Alzheimer type (stage 3) Mononeuritis multiplex due to sarcoidosis Hereditary motor and sensory neuropathy Ossitication of posterior longitudinal ligament Parkinson’s disease Cerebellar cortical atrophy (Holmes type) Essential tremor Herpes simplex encephalitis (residual state)
12 2 15 5 13 7 10 2 12 6 9 4 10 2 3 5 2 1
114 132 144 120 180 130 150 152 128 100 152 140 144 110 122 132 128 120
CEREBROSPINAL
FLUID ENDOTHELIN-1
IN ALZHEIMER’S
87
DISEASE
After centrifugation at 1000 x g for 10 min, supernatant of CSF or plasma was stored at -80% until assayed.
Pg 1 ml ,325,
(2)0 -l
Determination of ET-I CSF and plasma ET-l concentrations were determined with sandwich-enzyme immunoassay (sandwith-EIA) for human ET- 1. The details of the assay system were previously published (14). This system can detect ET-l as well as ET-2, but cannot detect ET-3 or big ET-l. Statistical analysis A value of ET- 1 in each group was given as mean + SD. Statistical analysis was performed using a 2tailed unpaired Student’s t test. Correlation coefficient was calculated by the data analysis software of Stat View II.
0.198zto.087
0.194M.026
i
(3) u
l
0.142ko.030
,125. $
C3)0 .
1
.
DC
AD
SDAT
n=7
n=5
n=6
1
Figure Cerebrospinal fluid endothelin- 1 concentrations in disease control (DC), Alzheimer’s disease (AD) and senile dementia of Alzheimer type (SDAT). Endothelin-I concentrations are given as mean f standard deviation. A small point corresponds to one data, medium-sized point corresponds to two data, and large-sized point corresponds to three data. Cerebrospinal endothelin-1 level was significantly lower in AD than in DC (*p < 0.05).
Results CSF ET-l levels in disease control (DC), AlzheimerS disease (AD) and senile dementia of Alzheimer type (SDAT) We found that ET-l was detectable in CSF (Table). The CSF ET- 1 concentrations in DC, AD and SDAT were 0.194 + 0.026 pg/ml (range, 0.15 to 0.22 pg/ml), 0.142 f 0.030 pg/ml (range, 0.09 to 0.17 pg/ml) and 0.198 f 0.087 pg/ml (range, 0.12 to 0.3 1 pg/ml), respectively (Figure). The CSF ET-1 level was significantly lower in AD group than in DC group (p < 0.05). However, the CSF ET-1 level in SDAT group was not significantly different from that in DC or AD group. Correlation between the CSF ET-l levels and various other factors Concerning the correlation coefficients between the CSF ET-l levels and various factors (age, duration from onset, systolic blood pressure, CSF protein level, plasma ET- 1 level), none of these factors had significant correlations with CSF ET- 1 levels in AD or SDAT group @ < 0.05). On the other hand, in DC group, only the age of patient was negatively correlated with the CSF ET-1 level (p < 0.05) (correlation coefficient: -0.928).
Relationship between CSF ET-1 level and clinical stage in Alzheimer type dementia Because the number of patients in AD or SDAT group was small, we dealt with the data of AD in conjunction with the data of SDAT to evaluate the relationship between the severity of dementia and the CSF ET-1 level. The CSF ET-I concentrations were0.150f0.000 instage 1,0.130*0.035 instage 2 and 0.202 + 0.085 in stage 3. No statistically significant differences were observed in these three groups.
Discussion We found that ET-l-like immunoreactivity was detectable in the samples of CSF with sandwichEIA. Though the monoclonal antibody for ET-1 in this assay crossreacts with ET-2, recent study with reverse phase high pressure liquid chromatography and the same sandwich-EIA showed the absence of ET-2 in the samples of human CSF (10). Therefore, ET-l-like immunoreactivity in our study is probably ET- 1 itself. Because the age distribution in AD group is not significantly different from that in DC group, it is possible to suppose that the lower level of CSF ET-I
88 in AD group reflects an event in the CNS. In fact, since the CSF ET-l level was not correlated with the plasma ET-1 level in AD or SDAT, it is unlikely that CSF ET-1 is derived from plasma ET-l. There is rather a possibility that CSF ET- 1 could be derived from the CNS neurons and could reflect the condition of the CNS ET-1 system. In this respect, the lower level of CSF ET-l in AD group suggests the possibility of an alteration in the CNS ET-l system in Alzheimer’s disease (e.g., degeneration, decreased function, etc.). In contrast to AD group, the CSF ET-l level in SDAT group was not significantly different from that in DC group. Since we could not collect data from disease control patients whose ages were matched with that of SDAT patients, the present data in DC group was not always adequate to the statistical analysis in DC and SDAT groups. In consideration of each level of CSF ET-l in SDAT group, 4 out of 6 indicated the lower levels than that in DC group. However, 2 out of 6 in SDAT group showed higher levels in CSF ET- 1. These two patients were bed-ridden at stage 3 for more than 2 years. From this relevant information, other factors might influence the CSF ET-l levels in these patients. In the present study, there were no significant differences in CSF ET-1 level among the three clinical stages. Because the CSF ET-1 level exhibited a lower concentration in earlier stages, this result may reflect the early alteration of the CNS ET-l system in Alzheimer type dementia.
References 1. Yanagisawa, M., Kurihara, H., Kimura, S., Tomobe, Y., Kobayashi, M., Mitsui, Y., Yazaki, Y ., Goto, K. and Ma&i, M. (1988). A novel potent vasoconstrictor peptide produced by vascular endothelial cells. Nature (London) 332: 411-415. 2. Yoshizawa, T., Kimura, S., Kanazawa, I., Uchiyama, Y., Yanaeisawa. M. andMasaki. T. (1989). Endothelm localizes in thedorsal’hom and acts on the spinal neurones: possible involvement of dihydropyridine-sensitive calcium channels and substance P release. Neuroscience Letters 102: 179-184.
NEUROPEPTIDES
3. Shinmi, O., Kimura, S., Yoshizawa, T., Sawamura, T., Uchiyama, Y., Sugita, Y., Kanazawa, I., Yanagisawa, M., Goto. K. andMasaki. T. (1989). Presence of endothelin-1 in porcine spinal cord: ‘isolation and sequence determination. Biochemical and Biophysical Research Communications 162: 340-346. 4. Shinmi, O., Kimura, S., Sawamura, T., Sugita, Y., Yoshizawa, T., Uchiyama, Y., Yanagisawa, M., Goto, K., Ma&i, T. and Kanazawa, I. (1989). Endothelin-3 is a novel neuropeptide: isolation and sequence determination of endothelin-1 and endothelin-3 in porcine brain. Biochemical and Biophysical Research Communications 164: 587-593. 5. Yoshizawa, T., Shinmi, O., Giaid, A., Yanagisawa, M., Gibson, S. J., Kimura, S., Uchiyama, Y., Polak, J. M., Masaki, T. and Kanazawa, I. (1990). Endothelin a novel peptide in the posterior pituitary system. 247: 462-464. 6. Hoffman, A., Keiser, H. R., Grossman, E., Goldstein, D. S., Gold, P. W. and Kling, M. Endothelin concentrations in cerebrospinal fluid in depressive patients [Letter]. (1989). Lancet 2 (8678-8679): 1519. 7. Fujimori, A., Yanagisawa, M., Saito, A., Goto, K., Ma&i, T., Mima, T., Takakura, K. and Shigeno, T. (1990). Endothehn inplasmaand cerebrospinal fluid ofpatients with subarachnoid haemorrhage [Letter]. Lancet 336: 633. 8. Hirata, Y., Matsunaga, T., Ando, K., Furukawa, T., Tsukagoshi, H. and Marumo, F. (1990). Presence ofendothelin-l-like immunoreactivity in human cerebrospinal fluid. Biochemical and Biophysical Research Communications 166: 1274-1278. 9. Suzuki, H., Sato, S., Suzuki, Y., Takekoshi, K., Ishihira, N. and Shimoda, S. (1990). Increased endothelin concentration in CSF from patients with subarachnoid hemorrhage. Acta Neurologica Scandinavica 81: 553-554. 10. Yamaji, T., Johshita, H., Ishibashi, M., Takaku, F., Ohno, H., Suzuki,N.,Matsumoto,H. andFujino,M. (1990). Endothelin family in human plasma and cerebrospinal fluid. Journal of Clinical Endocrinology and Metabolism 71: 1611-1615. 11. Kraus, G. E., Bucholz, R. D., Yoon, K. W., Knuepfer, M. M. and Smith. K. R. Jr. (1991). Cerebrosoinal fluid endothelin1 and endothelin-3‘ levels in normal and neurosurgical patients: a clinical study and literature review. Surgical Neurology 35: 20-29. 12. McKhann, G., Drachman, D., Folstein, M., Katzman, R., Price, D. and Stadlan, M. (1984). Clinical diagnosis of Alzheimer’s disease: report of the NINCDS-ADRDA work group under the auspices of department of health and human services task force on Alzheimer’s disease. Neurology 34: 939-944. 13. Cummings, J. L. and Benson, D. F. (1986). Dementia ofthe Alzheimer type. An inventory of diagnostic clinical features. Journal of the American Geriatrics Society 34: 12-19. 14. Suzuki, N., Matsumoto, H., Kitada, C., Masaki, T. and Fujino, M. (1989). A sensitive sandwich-enzyme immunoassay for human endothelin. Journal of Immunological Methods 118: 245-250.
Cerebrospinal Fluid Endothelin-1 in Alzheimer’s Disease and Senile Dementia of Alzheimer Type
T. YOSHIZAWA*, H. IWAMOTO”, H. MIZUSAWA”, N. SUZUKlt, H. MATSUMOTOt and I. KANAZAWA*S *Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba City, 305, Japan. t Tsukuba Research Laboratories, Takeda Chemical Industries, Ltd., Tsukuba City, 305, Japan. *(Present address) Department of Neurology, institute of Brain Research, School of Medicine, University of Tokyo, 113, Japan. (Correspondence and reprint request to TY) Abstract-We have measured the endothelin-1 concentrations in the cerebrospinal fluid samples from 5 patients with Alzheimer’s disease (AD), 6 patients with senile dementia of Alzheimer type (SDAT) and 7 patients with other diseases without dementia (disease control: DC). The cerebrospinal fluid endothelin-1 level was significantly lower in AD than in DC. No correlation was observed between cerebrospinal fluid endothelin-1 concentration and any other factors such as age, duration from onset, systolic blood pressure, cerebrospinal fluid protein level or plasma endothelin-1 concentration in AD or SDAT. These results suggest a possible alteration of the endothelin-1 system in the central nervous system in Alzheimer’s disease.
Introduction
In human cerebrospinal fluid (CSF), there are many kinds of neuropeptides which may be derived from the CNS neurons. Recently, ET-1 was also reported to be present in the CSF samples taken from patients with subarachnoid hemorrhage, cerebral hemorrhage, cerebral infarction, major depression and healthy volunteers (6-11). It is still unknown whether the source of ET-1 in human CSF is CNS neurons or cerebral blood vessels at present. However, the presence of ET in the porcine and rat CNS suggests a role for ET-1 as a neuropeptide in the human CNS as well. Alzheimer’s disease (AD) and senile dementia of Alzheimer type (SDAT) are neurodegenerative disorders characterized by progressive dementia which
Endothelin- 1 (ET- 1) was originally characterized as a 21 -amino acid vasoconstrictor peptide from endothelial cells, with a molecular weight of 2492 (1). We have demonstrated the presence of ET-l in the porcine central nervous system (CNS) and a depolarizing action on rat spinal neurons (2-5). Especially, in porcine and rat brain, ET-1 is localized in the posterior pituitary system and may modulate neurosecretion (5). These data suggest that ET- 1 may function as a neuropeptide in the porcine and rat CNS. Date received 2 December 199 1 Date accepted 10 February 1992
85
86
NEUROPEPTIDES
occur in middle and late life. Neuropathological and neurochemical analysis disclosed the degenerations of several neurotransmitter systems including neuropeptides which may be involved in the pathogenesis of dementia. Alterations in neurotransmitter markers or neuropeptides in CSF were also reported, which may reflect the degenerations of specific neuronal systems in CNS. However, there is no information for an alteration in the CSF ET- 1 level or the CNS ET-l system in AD and SDAT. In the present study, therefore, we determined CSF ET-l concentrations in patients with AD and SDAT compared with those of disease control.
Subjects and Methods Subjects The subjects data are summari ‘zed in the Table. 11 patients with Alzheimer type dementia (ATD) and 7 patients of disease control without dementia admitted to Tsukuba university hospital (Tsukuba) or Hatsuishi hospital (Chiba) were included in this study. All patients diagnosed as ATD met NINCDWADRDA diagnostic criteria for probable Alzheimer’s disease (12). No familial cases were
Table
Case
AD-l -2 -3 -4 -5 SDAT-1 -2 -3 -4 -5 -6 DC-1 -2 -3 -4 -5 -6 -7
included. The clinical stage of ATD patients was evaluated with the criteria of Cummings and Benson (13). ATD patients were divided into the following two groups according to the age of onset. 1) Alzheimer’s disease (AD) group; 5 patients (5 women) whose onsets were before the age of 65 years. Mean age of patients + standard deviation (SD) was 64 + 8.2.2) senile dementia of Alzheimer type (SDAT) group; 6 patients (1 man and 5 women) whose onsets were after the age of 65 years. Mean age + SD was 77.5 +4.7. Disease control (DC) group included 7 non-demented patients whose mean age +_SD was 58.9 f 9.5. The mean age in AD group was not significantly different from that in DC group. However, the mean age in SDAT group was higher than that in DC and AD group (p < 0.05, unpaired t test). None of the patients took any antihypertensive drug. CSF and blood samples After informed consent was given, we obtained CSF samples by lumbar puncture around noon. Blood samples were obtained from 4 AD patients and 6 SDAT patients before lumbar puncture. Each sample was collected in a polypropylene tube containing 300 KIU/ml of aprotinin and 2 mg/dl of EDTA.
Subjects’ profile and ET- 1 concentrations in cerebrospinal fluid and plasma samples
Age (years) 55
51 64 70 74 72 75 76 78 78 86 49 50 52 56 63 70 72
ND: not determined
Duration from onset
Systolic blood pressure
CSF protein
CSF ET-I
Plasma ET-I
(mmW
(mgjdl)
@@ml)
(mddl)
37 23 51 28 34 31 30 15 32 76 19 30 30 55 64 23 36 27
0.09 0.15 0.15 0.15 0.17 0.15 0.12 0.15 0.15 0.31 0.31 0.22 0.22 0.20 0.20 0.20 0.17 0.15
1.82 ND 1.67 2.45 1.64 2.11 2.44 4.35 1.72 1.77 2.11 ND ND ND ND ND ND ND
Sex
Diagnosis
(years)
F F F F F F M F F F F F F F M F M F
Alzheimer’s disease (stage 2) Alxheimer’s disease (stage 1) Alzheimer’s disease (stage 3) Alzheimer’s disease (stage 2) Alzheimer’s disease (stage 3) Senile dementia of Alzheimer type (stage 1) Senile dementia of Alzheimer type (stage 3) Senile dementia of Alzheimer type (stage 2) Senile dementia of Alzheimer type (stage 3) Senile dementia of Alzheimer type (stage 3) Senile dementia of Alzheimer type (stage 3) Mononeuritis multiplex due to sarcoidosis Hereditary motor and sensory neuropathy Ossitication of posterior longitudinal ligament Parkinson’s disease Cerebellar cortical atrophy (Holmes type) Essential tremor Herpes simplex encephalitis (residual state)
12 2 15 5 13 7 10 2 12 6 9 4 10 2 3 5 2 1
114 132 144 120 180 130 150 152 128 100 152 140 144 110 122 132 128 120
CEREBROSPINAL
FLUID ENDOTHELIN-1
IN ALZHEIMER’S
87
DISEASE
After centrifugation at 1000 x g for 10 min, supernatant of CSF or plasma was stored at -80% until assayed.
Pg 1 ml ,325,
(2)0 -l
Determination of ET-I CSF and plasma ET-l concentrations were determined with sandwich-enzyme immunoassay (sandwith-EIA) for human ET- 1. The details of the assay system were previously published (14). This system can detect ET-l as well as ET-2, but cannot detect ET-3 or big ET-l. Statistical analysis A value of ET- 1 in each group was given as mean + SD. Statistical analysis was performed using a 2tailed unpaired Student’s t test. Correlation coefficient was calculated by the data analysis software of Stat View II.
0.198zto.087
0.194M.026
i
(3) u
l
0.142ko.030
,125. $
C3)0 .
1
.
DC
AD
SDAT
n=7
n=5
n=6
1
Figure Cerebrospinal fluid endothelin- 1 concentrations in disease control (DC), Alzheimer’s disease (AD) and senile dementia of Alzheimer type (SDAT). Endothelin-I concentrations are given as mean f standard deviation. A small point corresponds to one data, medium-sized point corresponds to two data, and large-sized point corresponds to three data. Cerebrospinal endothelin-1 level was significantly lower in AD than in DC (*p < 0.05).
Results CSF ET-l levels in disease control (DC), AlzheimerS disease (AD) and senile dementia of Alzheimer type (SDAT) We found that ET-l was detectable in CSF (Table). The CSF ET- 1 concentrations in DC, AD and SDAT were 0.194 + 0.026 pg/ml (range, 0.15 to 0.22 pg/ml), 0.142 f 0.030 pg/ml (range, 0.09 to 0.17 pg/ml) and 0.198 f 0.087 pg/ml (range, 0.12 to 0.3 1 pg/ml), respectively (Figure). The CSF ET-1 level was significantly lower in AD group than in DC group (p < 0.05). However, the CSF ET-1 level in SDAT group was not significantly different from that in DC or AD group. Correlation between the CSF ET-l levels and various other factors Concerning the correlation coefficients between the CSF ET-l levels and various factors (age, duration from onset, systolic blood pressure, CSF protein level, plasma ET- 1 level), none of these factors had significant correlations with CSF ET- 1 levels in AD or SDAT group @ < 0.05). On the other hand, in DC group, only the age of patient was negatively correlated with the CSF ET-1 level (p < 0.05) (correlation coefficient: -0.928).
Relationship between CSF ET-1 level and clinical stage in Alzheimer type dementia Because the number of patients in AD or SDAT group was small, we dealt with the data of AD in conjunction with the data of SDAT to evaluate the relationship between the severity of dementia and the CSF ET-1 level. The CSF ET-I concentrations were0.150f0.000 instage 1,0.130*0.035 instage 2 and 0.202 + 0.085 in stage 3. No statistically significant differences were observed in these three groups.
Discussion We found that ET-l-like immunoreactivity was detectable in the samples of CSF with sandwichEIA. Though the monoclonal antibody for ET-1 in this assay crossreacts with ET-2, recent study with reverse phase high pressure liquid chromatography and the same sandwich-EIA showed the absence of ET-2 in the samples of human CSF (10). Therefore, ET-l-like immunoreactivity in our study is probably ET- 1 itself. Because the age distribution in AD group is not significantly different from that in DC group, it is possible to suppose that the lower level of CSF ET-I
88 in AD group reflects an event in the CNS. In fact, since the CSF ET-l level was not correlated with the plasma ET-1 level in AD or SDAT, it is unlikely that CSF ET-1 is derived from plasma ET-l. There is rather a possibility that CSF ET- 1 could be derived from the CNS neurons and could reflect the condition of the CNS ET-1 system. In this respect, the lower level of CSF ET-l in AD group suggests the possibility of an alteration in the CNS ET-l system in Alzheimer’s disease (e.g., degeneration, decreased function, etc.). In contrast to AD group, the CSF ET-l level in SDAT group was not significantly different from that in DC group. Since we could not collect data from disease control patients whose ages were matched with that of SDAT patients, the present data in DC group was not always adequate to the statistical analysis in DC and SDAT groups. In consideration of each level of CSF ET-l in SDAT group, 4 out of 6 indicated the lower levels than that in DC group. However, 2 out of 6 in SDAT group showed higher levels in CSF ET- 1. These two patients were bed-ridden at stage 3 for more than 2 years. From this relevant information, other factors might influence the CSF ET-l levels in these patients. In the present study, there were no significant differences in CSF ET-1 level among the three clinical stages. Because the CSF ET-1 level exhibited a lower concentration in earlier stages, this result may reflect the early alteration of the CNS ET-l system in Alzheimer type dementia.
References 1. Yanagisawa, M., Kurihara, H., Kimura, S., Tomobe, Y., Kobayashi, M., Mitsui, Y., Yazaki, Y ., Goto, K. and Ma&i, M. (1988). A novel potent vasoconstrictor peptide produced by vascular endothelial cells. Nature (London) 332: 411-415. 2. Yoshizawa, T., Kimura, S., Kanazawa, I., Uchiyama, Y., Yanaeisawa. M. andMasaki. T. (1989). Endothelm localizes in thedorsal’hom and acts on the spinal neurones: possible involvement of dihydropyridine-sensitive calcium channels and substance P release. Neuroscience Letters 102: 179-184.
NEUROPEPTIDES
3. Shinmi, O., Kimura, S., Yoshizawa, T., Sawamura, T., Uchiyama, Y., Sugita, Y., Kanazawa, I., Yanagisawa, M., Goto. K. andMasaki. T. (1989). Presence of endothelin-1 in porcine spinal cord: ‘isolation and sequence determination. Biochemical and Biophysical Research Communications 162: 340-346. 4. Shinmi, O., Kimura, S., Sawamura, T., Sugita, Y., Yoshizawa, T., Uchiyama, Y., Yanagisawa, M., Goto, K., Ma&i, T. and Kanazawa, I. (1989). Endothelin-3 is a novel neuropeptide: isolation and sequence determination of endothelin-1 and endothelin-3 in porcine brain. Biochemical and Biophysical Research Communications 164: 587-593. 5. Yoshizawa, T., Shinmi, O., Giaid, A., Yanagisawa, M., Gibson, S. J., Kimura, S., Uchiyama, Y., Polak, J. M., Masaki, T. and Kanazawa, I. (1990). Endothelin a novel peptide in the posterior pituitary system. 247: 462-464. 6. Hoffman, A., Keiser, H. R., Grossman, E., Goldstein, D. S., Gold, P. W. and Kling, M. Endothelin concentrations in cerebrospinal fluid in depressive patients [Letter]. (1989). Lancet 2 (8678-8679): 1519. 7. Fujimori, A., Yanagisawa, M., Saito, A., Goto, K., Ma&i, T., Mima, T., Takakura, K. and Shigeno, T. (1990). Endothehn inplasmaand cerebrospinal fluid ofpatients with subarachnoid haemorrhage [Letter]. Lancet 336: 633. 8. Hirata, Y., Matsunaga, T., Ando, K., Furukawa, T., Tsukagoshi, H. and Marumo, F. (1990). Presence ofendothelin-l-like immunoreactivity in human cerebrospinal fluid. Biochemical and Biophysical Research Communications 166: 1274-1278. 9. Suzuki, H., Sato, S., Suzuki, Y., Takekoshi, K., Ishihira, N. and Shimoda, S. (1990). Increased endothelin concentration in CSF from patients with subarachnoid hemorrhage. Acta Neurologica Scandinavica 81: 553-554. 10. Yamaji, T., Johshita, H., Ishibashi, M., Takaku, F., Ohno, H., Suzuki,N.,Matsumoto,H. andFujino,M. (1990). Endothelin family in human plasma and cerebrospinal fluid. Journal of Clinical Endocrinology and Metabolism 71: 1611-1615. 11. Kraus, G. E., Bucholz, R. D., Yoon, K. W., Knuepfer, M. M. and Smith. K. R. Jr. (1991). Cerebrosoinal fluid endothelin1 and endothelin-3‘ levels in normal and neurosurgical patients: a clinical study and literature review. Surgical Neurology 35: 20-29. 12. McKhann, G., Drachman, D., Folstein, M., Katzman, R., Price, D. and Stadlan, M. (1984). Clinical diagnosis of Alzheimer’s disease: report of the NINCDS-ADRDA work group under the auspices of department of health and human services task force on Alzheimer’s disease. Neurology 34: 939-944. 13. Cummings, J. L. and Benson, D. F. (1986). Dementia ofthe Alzheimer type. An inventory of diagnostic clinical features. Journal of the American Geriatrics Society 34: 12-19. 14. Suzuki, N., Matsumoto, H., Kitada, C., Masaki, T. and Fujino, M. (1989). A sensitive sandwich-enzyme immunoassay for human endothelin. Journal of Immunological Methods 118: 245-250.