(Stroke. 1996;27:219-223.)
© 1996 American Heart Association, Inc.
Articles |
From the Department of Neurology, University of Münster (Germany).
Correspondence to Peter Zunker, MD, Department of Neurology, University of Münster, Albert-Schweitzer-Str 33, D-48129 Münster, Germany.
| Abstract |
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Methods One hundred ninety-four consecutive patients presenting with symptomatic cerebrovascular disease were assigned to three subgroups that were differentiated by clinical presentations, brain imaging studies, and extracranial as well as transcranial vascular ultrasound findings: (1) patients with lacunes (n=20), (2) patients with subcortical arteriosclerotic encephalopathy (n=35), and (3) patients with strokes due to large-vessel disease (n=99). Patients who had suffered a cryptogenic (n=9) or cardioembolic (n=16) stroke or who showed characteristics of the microangiopathy and macroangiopathy groups (n=15) were not further evaluated. Thirty patients without manifestations of cerebrovascular disease were also examined. Fasting blood glucose, insulin, and C-peptide levels were determined in all subjects.
Results There were no significant differences in age or sex among the three groups and control patients. Insulin levels were significantly higher in the lacunar group compared with the subcortical arteriosclerotic encephalopathy group, the macroangiopathy group, and the control patients (median [interquartile range]: 103.8 [198.6], 72.0 [103.2], 66.0 [57.0], and 52.2 [57.0] pmol/L, respectively; all P<.05, Mann-Whitney test). There was a statistically significant difference in insulin concentrations between the microangiopathy group (subcortical arteriosclerotic encephalopathy and lacunes) and the macroangiopathy and control groups (81.0 [110.4], 66.0 [57.0], and 55.2 [57.0] pmol/L, respectively; all P<.05, Mann-Whitney). The same was true for the distribution of C-peptide levels and to a minor extent blood glucose values, but these differences failed to reach statistical significance.
Conclusions Elevated insulin levels potentially represent a pathogenetic factor in the development of cerebral small-vessel disease, predominantly in patients presenting with lacunes. Whether this is due solely to atherosclerotic changes of the small penetrating arteries or whether changes in hemorheology are operative as well remains to be evaluated.
Key Words: atherosclerosis small vessel disease lacunar infarction insulin
| Introduction |
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On the basis of these experimental data and postmortem findings, we investigated whether elevated insulin levels in humans are associated with symptomatic cerebral microangiopathy compared with stroke due to large-vessel disease of the brain-supplying arteries.21 22 23 24 25 26 27
| Subjects and Methods |
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Blood was drawn for determination of levels of fasting insulin, fasting capillary blood glucose, and C peptide (Coat-A-Count Insulin RIA and Double Antibody C-Peptide, Diagnostic Product Corporation).
Diagnosis of hypertension was based either on the presence of antihypertensive treatment on admission or on three blood pressure values exceeding 160 mm Hg (systolic value) and/or 95 mm Hg (diastolic value) at least 3 days after an acute event.
Diagnosis of DM was assigned for patients either already receiving antidiabetic therapy on admission or with pathological oral glucose tolerance tests. Evaluation of the fasting glucose levels was used as a screening test in all cases, followed by a tolerance test if the level exceeded 6.38 mmol/L. A detailed history concerning actual and former smoking behavior was obtained from all patients.
The following patients were excluded from this study: (1) patients with potential cardioembolic sources of stroke (n=16; atrial fibrillation [n=10], atrial thrombus [n=2], infective endocarditis [n=1], and hypokinetic region of the left ventricle after anterior myocardial infarction [n=3]), (2) patients with cryptogenic stroke (n=9), and (3) patients with a combined macroangiopathy and microangiopathy (n=15). On the basis of the results of these investigations, the patients were divided into three etiologic subgroups.
The lacunar group (group 1) included all patients who fulfilled the following criteria: (1) normal findings on vascular ultrasound examination; (2) small deep infarctions of <1.5 cm in diameter including the deep white matter, basal ganglia, internal capsule, thalamus, and brain stem23 on brain imaging studies; and (3) clinical symptoms compatible with lacunar syndrome (pure motor, sensory stroke, ataxic hemiparesis, sensorimotor stroke, and dysarthria clumsy hand syndrome).
Group 2 consisted of patients suffering from SAE. This diagnosis was based on the following criteria: (1) diffuse periventricular and subcortical hypodensity on CT scan or hyperintensity of the same areas on T2-weighted MRI scans, (2) normal findings on vascular ultrasound examination, and (3) at least two typical clinical symptoms (eg, disorders of memory and cognition, psychiatric disturbances [disorientation, confusion, irritability, depression], long tract signs, and deterioration of gait and sphincter control). All these patients were free of a family history of strokelike episodes, dementia, and psychiatric disorders suggesting CADASIL disease.31
Group 3 consisted of patients with occlusive disease of the cerebral arteries. This was defined as a >50% stenosis detectable by extracranial or transcranial Doppler examination and/or as a local reduction in diameter >30% visible in the duplex scan of the carotid, subclavian, and vertebral arteries (V0, V1, and V2). This limit clearly exceeds normal age-related atherosclerotic changes.
Thirty patients from the neurological ward who had muscle contraction headache (n=12), herniated disks (n=8), or Parkinson's disease (n=10) underwent the same examinations and served as the control group. Thirteen patients from this group underwent MRI and 9 underwent CT scan of the skull.
Statistical analysis was performed using the two-sample
t test for normally distributed data, and the Mann-Whitney
test was used for data that were not normally distributed. Distribution
of frequency was evaluated with the
2 test.
Significance was declared at a level of P<.05.
| Results |
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There were no significant differences in age distribution among the
three groups and the normal control subjects (68±10, 67±10,
63±12,
and 67±9 years [P>.05, paired t test];
men/women distribution: 13/7, 24/11, 66/33, and 16/14
[P>.05,
2 test], groups 1, 2, 3,
and normal control subjects, respectively). The prevalence of
hypertension, DM type II, and smoking behavior is shown in Table
1
.
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The lacunar group contained the most patients with DM. None of the
examined patients suffered from type I DM. All patients with
cerebrovascular disease showed a statistically higher prevalence of
hypertension and nicotine abuse compared with the control group.
Insulin levels were significantly higher in patients with lacunar
stroke (group 1) compared with the patients with SAE, with
macroangiopathy, and the normal control subjects (median
[interquartile range]: 103.8 [198.6], 72.0
[103.2], 66.0
[57.9], 55.2 [57.0] pmol/L, respectively; all
P<.05,
Mann-Whitney test; Table 2
). The lacunar group also
showed statistically higher C-peptide levels compared with the control
patients (1.1 [0.97] and 0.73 [0.43] nmol/L, respectively;
P<.05, Mann-Whitney; Table 2
).
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Insulin and C-peptide levels did not correlate with glucose levels. Nine patients (45%) of the lacunar group, 16 (45%) of the SAE group, and 25 (25%) of the macroangiopathy group had normal blood glucose levels, whereas their insulin and/or C-peptide levels were elevated. Ten patients (18%) with cerebral microangiopathy and long-standing type II DM (lacunar group, n=6 [30%]; SAE, n=4 [11.4%]) and 15 of 99 patients (15%) of the macroangiopathy group had elevated blood glucose but normal or even low insulin and C-peptide values.
The prevalence of arterial hypertension in patients with hyperinsulinism was 76% (25 of 33) in the microangiopathy group (n=55), 68% (22 of 32) in the macroangiopathy group (n=99), and 25% (2 of 8) in the control group (n=30).
| Discussion |
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In accordance with previous studies, we also found an association between hyperinsulinism and hypertension.4 Still, this finding does not argue against the pathogenetic role of hyperinsulinemia in the development of cerebral microangiopathy. Furthermore, it cannot be the sole explanation for our results, since arterial hypertension was only diagnosed in 25 (76%) of the 33 patients with hyperinsulinemia in the microangiopathy group (lacunes and SAE).
Elevated insulin levels obviously do not play a role in the development of macroangiopathy of the brain-supplying neck arteries. Serum insulin and C-peptide values in these patients were in the same range as those in the control group. Similar results were reported on the relationship between hyperinsulinism and coronary heart disease.8 9 This could potentially be explained by the higher susceptibility of the cerebral microvascular endothelium to the mitogenic and metabolic effects of insulin compared with endothelium from other vessel territories.
High insulin and C-peptide levels are not necessarily equivalent to high blood glucose levels, as was demonstrated by the elevated insulin and/or C-peptide levels but normal blood glucose concentrations of 25 patients from the microangiopathy group. Although the same finding was recently published by Kuusisto et al,14 who identified high fasting insulin levels as an independent risk factor for stroke in nondiabetic patients, these authors provided no information concerning various stroke subtypes.
The large interquartile ranges of the insulin and C-peptide concentrations found in our microangiopathy groups were due to 10 patients with long-standing type II DM who had low insulin and C-peptide levels but high blood glucose concentrations. According to the current understanding of the temporal development of type II DM, this finding must be interpreted as an exhaustion of the insulin production after a preceding stage of hyperinsulinism.32 33 34 35
Small-vessel disease is characterized by a thickening of the basement membrane, proliferation of the endothelium, and the development of microatheroma with a high content of foam cells.21 36 Insulin can promote such changes in various ways. First, its metabolic and mitogenic effects on cerebral small-vessel endothelium may contribute to its "primary injury." Subsequent dysfunction of the endothelial cells leads to the adhesion of monocytes and platelets.14 15 16 17 19 37 38 39 Second, the capability of insulin to increase the 3-hydroxy-3-methylglutarylcoenzyme A reductase activity in monocytes and to stimulate low-density lipoprotein binding to their cell membrane may cause the formation of foam cells.40 41 This has been shown to correspond to the lipid content of arterial lesions and wall thickening in experimental animal models after long-term treatment with insulin.42 43 Third, insulin stimulates migration and proliferation of smooth muscle cells16 17 43 and enhances their cholesterol synthesis in cell cultures.44
Insulin also influences fibrinolysis. Vague et al45 reported that the changes in insulin plasma levels even within the physiological range modulate the fibrinolytic system at the PAI-1 level. Schneider and Sobel46 demonstrated increased synthesis of PAI-1 when cultured hepatocytes (hepg2) were stimulated by insulin and insulinlike growth factor. Even proinsulin augments the activity of PAI-1 in endothelial cells.47 In human atherosclerotic arteries, the expression of the PAI-1 gene is predominantly localized in the mesenchymal-appearing neointimal cells, suggesting that the expression of this gene is linked to the cellular proliferative response.48 Thus, injured endothelium can lead to increased mitogenic activity and attract and stimulate neighboring smooth muscle cells. A reduction of the fibrinolytic activity by an insulin-induced increased PAI-1 synthesis has also been postulated.45 47 These pathophysiological mechanisms based on the high susceptibility of cerebral small-vessel endothelium to the mitogenic and metabolic effects of insulin are in line with our findings in patients with cerebral small-vessel disease, which suggest that insulin does not significantly contribute to the development of macroangiopathy of the brain-supplying arteries. Hypertension and smoking are the most relevant risk factors for cerebral large-vessel disease.49 50
In conclusion, our findings of high insulin and C-peptide levels in patients with cerebral microangiopathy, and especially in those with lacunes, as opposed to patients with large-vessel disease and control subjects are in agreement with previous studies reporting a strong metabolic and mitogenic influence of insulin on small-vessel endothelium. Whether elevated insulin acts solely by stimulating the atherosclerotic process of the small penetrating arteries as such, or whether the suppression of the endogenous fibrinolysis is another crucial pathogenetic mechanism for the manifestation of cerebral microangiopathy, remains unclear. Our results suggest that hypertension and smoking, but not elevated insulin and C-peptide levels, stimulate atherosclerosis of the supra-aortic large brain arteries.
| Selected Abbreviations and Acronyms |
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| Acknowledgments |
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Received July 10, 1995; revision received October 9, 1995; accepted October 27, 1995.
| References |
|---|
|
|
|---|
2. Stout RW, Vallence-Owen J. Insulin and atheroma. Lancet. 1969;1:1078-1080. [Medline] [Order article via Infotrieve]
3. Stout RW. Insulin and atheroma: an update. Lancet. 1987;1:1077-1079. [Medline] [Order article via Infotrieve]
4. Stout RW. Insulin and atheroma: 20-yr perspective. Diabetes Care. 1990;13:631-654. [Abstract]
5. Jarrett RJ. Is insulin atherogenic? Diabetologica. 1988;31:71-75. [Medline] [Order article via Infotrieve]
6. Pyörälä K, Savolainen E, Kaukola S, Hapakoski J. High plasma insulin as a coronary heart disease risk factor. In: Eschwege E, ed. Advances in Diabetes Epidemiology. INSERM Symposium. Amsterdam, Netherlands: Elsevier; 1982:143-148.
7. Eschwege E, Richard JL, Thibult N, Ducimetiere P, Warnet JM, Claude JR, Rosselin GE. Coronary heart disease mortality in relation with diabetes, blood glucose and plasma insulin levels: the Paris Prospective Study ten years later. Horm Metab Res. 1985;15(suppl):41-46.
8. Fontbonne A, Charles MA, Thibult N, Richard JL, Claude JR, Warnet JM, Rosselin GE, Eschwege E. Hyperinsulinemia as a predictor of coronary heart disease mortality in a healthy population: the Paris prospective population study, 15-year follow-up. Diabetologia. 1991;34:356-361. [Medline] [Order article via Infotrieve]
9. Jarrett RJ. Why is insulin not a risk factor for coronary heart disease? Diabetologia. 1994;37:945-947. [Medline] [Order article via Infotrieve]
10. Welborn TA, Wearne K. Coronary heart disease incidence and mortality in Busselton with reference to glucose and insulin concentration. Diabetes Care. 1979;2:154-160. [Abstract]
11. Gertler MM, Leetma HE, Saluste E, Welsh JJ, Rusk HA, Covalt DA, Rosenberger J. Carbohydrate, insulin and lipid interrelationship in ischemic vascular disease. Geriatrics. 1970;25:134-148. [Medline] [Order article via Infotrieve]
12. Gertler MM, Leetma HE, Saluste E, Covalt DA, Rosenberger JL. Covert diabetes mellitus in ischemic heart and cerebrovascular disease. Geriatrics. 1972;27:105-120.
13.
Gertler MM, Leetma HE, Koutrouby RJ, Johnson ED.
The assessment of insulin, glucose and lipids in ischemic
thrombotic cerebrovascular disease. Stroke. 1975;6:77-84.
14. Kuusisto J, Mykkänen L, Pyörälä K, Laakso M. Noninsulin-dependent diabetes and its metabolic control are important predictors of stroke in elderly subjects. Stroke. 1994;25:1157-1164. [Abstract]
15. Vinters HV, Berliner JA. The blood vessel wall as an insulin target tissue. Diabete Metab. 1987;13:294-300. [Medline] [Order article via Infotrieve]
16. King GL, Buzney SM, Kahn CR, Hetu N, Buchwald S, MacDonald SG, Rand LI. Differential responsiveness to insulin of endothelial and support cells from micro- and macrovessels. J Clin Invest. 1983;71:974-979.
17. Berliner JA, Vinters HV, Karasic D, Cancilla PA, Frank HJL. Insulin stimulation of amino-acid uptake in aortic and capillary endothelial cells. J Cell Biol. 1983;97:163a Abstract.
18. King GL, Goodman AD, Buzney S, Moses A, Kahn CR. Receptors and growth-promoting effects of insulin and insulin-like growth factors on cells from bovine retinal capillaries and aorta. J Clin Invest. 1985;75:1028-1036.
19. Vinters HV, Berliner JA, Beck DW, Maxwell K, Bready JV, Cancilla PA. Insulin stimulates DNA synthesis in cerebral microvessel endothelium and smooth muscle. Diabetes. 1985;34:964-969. [Abstract]
20. Vinters HV, Reave S, Costello P, Girvin JP, Moore SA. Isolation and culture of cells derived from human cerebral microvessels. Cell Tissue Res. 1987;249:657-661. [Medline] [Order article via Infotrieve]
21.
Alex M, Baron EK, Goldenberg S, Blumenthal HT.
An autopsy study of cerebrovascular accident in diabetes
mellitus. Circulation. 1962;25:663-673.
22. Caplan LR. Lacunar infarction: a neglected concept. Geriatrics. 1976;31:71-75.
23.
Miller VT. Lacunar stroke. Arch
Neurol. 1983;40:129-134.
24.
Leifer D, Buonanno FS, Richardson EP.
Clinicopathologic correlations of cranial magnetic resonance imaging of
periventricular white matter.
Neurology. 1990;40:911-918.
25.
Kinkel WR, Jacobs L, Polachini I, Bates V, Reid R,
Heffner J. Subcortical arteriosclerotic
encephalopathy. Arch Neurol. 1985;42:951-959.
26. Fisher CM. Binswanger's encephalopathy: a review. J Neurol. 1989;236:65-79. [Medline] [Order article via Infotrieve]
27.
Babikian V, Ropper AH. Binswanger's disease: a
review. Stroke. 1987;18:2-12.
28.
Sitzer M, Fürst G, Fischer H, Siebler M, Fehling
ST, Kleinschmidt A, Kahn T, Steinmetz H. Between-method
correlation in quantifying internal carotid stenosis.
Stroke. 1993;24:1513-1518.
29. Von Reutern G-M, Büdingen HJ. Ultraschalldiagnostik der hirnversorgenden Arterien. Dopplersonographie der extra- und intrakraniellen Arterien, Duplex-Sonographie. Stuttgart, Germany/New York, NY: Georg Thieme Inc; 1989:148-243.
30. Ley-Pozo J, Ringelstein EB. Noninvasive detection of occlusive disease of the carotid siphon and middle cerebral artery. Ann Neurol. 1990;20:640-647.
31. Bousser MG, Tournier-Lasserve E. Summary of the proceedings of the First International Workshop on CADASIL. Stroke. 1994;25:704-707. [Medline] [Order article via Infotrieve]
32. Mehnert H, Schöffling K, Standl E, Usadel K-H. Diabetologie in Klinik und Praxis. Stuttgart, Germany/New York, NY: Georg Thieme Inc; 1994:55-79.
33. Warram JH, Martin BC, Krolewski AS, Soelder JS, Kahn CR. Slow glucose removal rate and hyperinsulinemia precede the development of type II diabetes in the offspring of diabetic parents. Ann Intern Med. 1990;113:909-915.
34. Eriksson J, Franssila-Kallunki A, Ekstand A, Saloranta C, Widen E, Schalin C, Grop L. Early metabolic defects in persons at increased risk for non-insulin-dependent diabetes mellitus. N Engl J Med. 1989;321:334-337.
35. Johnson KH, O'Brien TD, Betsholtz C, Westermark P. Islet amyloid, islet amyloid polypeptide, and diabetes mellitus. N Engl J Med. 1989;321:513-518. [Abstract]
36.
Bamford JM, Warlow CP. Evolution and testing of
the lacunar hypothesis. Stroke. 1988;19:1074-1082.
37. Badimon L, Badimon JJ, Penny W, Webster MW, Chesebro JH, Fuster V. Endothelium and atherosclerosis. J Hypertens. 1992;10:43-50.
38. Ross R. The pathogenesis of atherosclerosis: an update. N Engl J Med. 1986;314:488-500. [Medline] [Order article via Infotrieve]
39. Ross R. The pathogenesis of atherosclerosis: a perspective for the 1990s. Nature. 1993;362:801-809. [Medline] [Order article via Infotrieve]
40. Krone W, Greten H. Evidence for post-transscriptional regulation by insulin of 3-hydroxy-3-methylglutaryl coenzyme A reductase and sterol synthesis in human mononuclear leucocytes. Diabetologica. 1984;26:366-369. [Medline] [Order article via Infotrieve]
41. Krone W, Nagele H, Behnke B, Greten H. Opposite effects of insulin and catecholamines on LDL-receptor activity in human mononuclear leucocytes. Diabetes. 1988;37:1386-1391. [Abstract]
42. Sato Y, Shiraishi S, Oshida Y, Ishijuro T, Sakamoto N. Experimental atherosclerosis-like lesions induced by hyperinsulinism in Wistar rats. Diabetes. 1989;38:91-96. [Abstract]
43. Pfeifle B, Ditschuneit H. Effect of insulin on growth of human arterial smooth muscle cells. Diabetologica. 1981;20:155-158. [Medline] [Order article via Infotrieve]
44. Stout RW. Insulin and atherogenesis. Eur J Epidemiol. 1992;suppl 1:134-135.
45. Vague P, Vague IJ, Aillaud MF, Badier C, Viard R, Alessi MC, Colen D. Between blood fibrinolytic activity, plasminogen activator inhibitor plasma insulin level and relative body weight in normal and obese. Metabolism. 1986;35:250-253. [Medline] [Order article via Infotrieve]
46.
Schneider DJ, Sobel BE. Augmentation of
synthesis of plasminogen activator
inhibitor type 1 by insulin and insulin-like growth
factor type 1: implications for vascular disease in
hyperinsulinemic states. Proc Natl Acad
Sci U S A. 1991;88:9959-9963.
47. Schneider DJ, Nordt TK, Sobel BE. Stimulation by proinsulin of expression of activator inhibitor type-1 in endothelial cells. Diabetes. 1992;41:890-895. [Abstract]
48.
Schneiderman J, Sawdey MS, Keeton MR, Bordin GM,
Bernstein EF, Dilley RB, Loskutoff DJ. Increased type 1
plasminogen activator inhibitor
gene expression in atherosclerotic human arteries. Proc
Natl Acad Sci U S A. 1992;89:6998-7002.
49.
Yasaka M, Yamaguchi T, Shichiri M. Distribution
of atherosclerosis and risk factors in atherothrombotic
occlusion. Stroke. 1993;24:206-211.
50.
Sutton-Tyrrell K, Alcorn HG, Wolfson SK, Kelsey SF,
Kuller LH. Predictors of carotid stenosis in older
adults with and without isolated systolic hypertension.
Stroke. 1993;24:355-361.
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