Fibrosis in diabetes complications: pathogenic mechanisms and circulating and urinary markers.

Diabetes mellitus is characterized by a lack of insulin causing elevated blood glucose, often with associated insulin resistance. Over time, especially in genetically susceptible individuals, such chronic hyperglycemia can cause tissue injury. One pathological response to tissue injury is the development of fibrosis, which involves predominant extracellular matrix (ECM) accumulation. The main factors that regulate ECM in diabetes are thought to be pro-sclerotic cytokines and protease/anti-protease systems. This review will examine the key markers and regulators of tissue fibrosis in diabetes and whether their levels in biological fluids may have clinical utility.

Smoking, fasting serum insulin, and obesity are the predictors of carotid atherosclerosis in relatively young subjects.

The purpose of this study was to identify predictors of atherosclerosis in a healthy young cohort comprised of 241 subjects who underwent a regular employee medical check-up at Ohshima National Sanatorium over a 9-month period. All subjects underwent carotid ultrasound examinations to determine maximal common carotid artery intima media thickness. In addition, serum total cholesterol, triglycerides, high-density lipoprotein cholesterol, blood urea nitrogen, creatinine, glucose, and insulin were evaluated. The subjects were relatively young (mean age, 44 years; range, 18 to 62 years), with 130 females (54%) and 111 males (46%). Maximal common carotid artery intima media thickness was predicted by smoking habit, body mass index, fasting blood sugar, fasting serum insulin, and systolic blood pressure (F(5,235) = 52.8, P < 10(-5)). There was clear separation in common carotid artery intima media thickness values based on body mass index, smoking, and fasting serum insulin, and somewhat more overlap with systolic blood pressure and fasting blood sugar. These findings suggest that smoking and high values of body mass index, fasting serum insulin, systolic blood pressure, and fasting blood sugar are warning factors for early atherosclerosis development, and could conceivably serve as the basis of diagnostic screening. Smoking is particularly deleterious, as smokers with high body mass index, high fasting serum insulin, or high systolic blood pressure tend to have larger common carotid artery intima media thickness values than would have been predicted by consideration solely of the individual risk factors.

Tumor necrosis factor-alpha neutralization reduced cerebral edema through inhibition of matrix metalloproteinase production after transient focal cerebral ischemia.

After focal cerebral ischemia, tumor necrosis factor-alpha deteriorates cerebral edema and survival rate. Therefore, tumor necrosis factor-alpha neutralization could reduce cerebral microvascular permeability in acute cerebral ischemia. Left middle cerebral artery occlusion for 120 mins followed by reperfusion was performed with the thread method under halothane anesthesia in Sprague-Dawley rats. Antirat tumor necrosis factor-alpha neutralizing monoclonal antibody with a rat IgG Fc portion (15 mg/kg) was infused intravenously right after reperfusion. Stroke index score, infarct volume, cerebral specific gravity, and the endogenous expression of tumor necrosis factor-alpha, matrix metalloproteinase (MMP)-2, MMP-9, and membrane type 1-MMP in the brain tissue were quantified in the ischemic and matched contralateral nonischemic hemisphere. In the antitumor necrosis factor-alpha neutralizing antibody-treated rats, infarct volume was significantly reduced (P=0.014, n=7; respectively), and cerebral specific gravity was dramatically increased in the cortex and caudate putamen (P<0.001, n=7; respectively) in association with a reduction in MMP-9 and membrane type 1-MMP upregulation. Tumor necrosis factor-alpha in the brain tissue was significantly elevated in the ischemic hemisphere 6 h after reperfusion in the nonspecific IgG-treated rats (P=0.021, n=7) and was decreased in the antitumor necrosis factor-alpha neutralizing antibody-treated rats (P=0.001, n=7). Postreperfusion treatment with antirat tumor necrosis factor-alpha neutralizing antibody reduced brain infarct volume and cerebral edema, which is likely mediated by a reduction in MMP upregulation.

Plasma adrenomedullin and carotid atherosclerosis in atherothrombotic ischemic stroke.

OBJECTIVE: Adrenomedullin is known to exert anti-atherosclerotic actions by inhibiting proliferation and migration of smooth muscle cells in vitro. Here we examine the relationship between the plasma concentration of adrenomedullin and ultrasonographic characteristics of carotid arteries both in ischemic stroke and in the absence of cerebrovascular disease. METHODS: We studied 61 patients with atherothrombotic ischemic stroke in the chronic phase and 50 patients without any cerebrovascular disease. Intima-media thickness and vascular lumen diameters were evaluated by carotid ultrasonography. Plasma mature-adrenomedullin was determined by radioimmunoassay. RESULTS: Plasma mature-adrenomedullin in the patients with atherothrombotic ischemic stroke in the chronic phase (2.01 +/- 0.58 fmol/ml) was significantly higher than that in the patients without any cerebrovascular disease (1.24 +/- 0.18 fmol/ml, P < 0.001). With multiple regression analysis, plasma mature-adrenomedullin was found to be predicted by: stroke status (atherothrombotic ischemic stroke versus no cerebrovascular disease), diabetes status (yes/no), left ventricular ejection fraction, internal carotid artery intima-media thickness, and common carotid artery pressure strain elastic modulus (R = 0.79; F5,105 = 85.39, P < 0.0001). CONCLUSION: Plasma mature-adrenomedullin showed significantly positive associations with carotid atherosclerosis and atherothrombotic ischemic stroke, independent of systolic blood pressure.