Diabetes has emerged as a major threat to worldwide health. The increasing incidence of diabetes in young individuals is particularly worrisome given that the disease is likely to evolve over a period of years. In 1972, the existence of a diabetic cardiomyopathy was proposed based on the experience with four adult diabetic patients who suffered from congestive heart failure in the absence of discernible coronary artery disease, valvular or congenital heart disease, hypertension, or alcoholism. The exact mechanisms underlying the disease are unknown; however, an important component of the pathological alterations observed in these hearts includes the accumulation of extracellular matrix (ECM) proteins, in particular collagens. The excess deposition of ECM in the heart mirrors what occurs in other organs such as the kidney and peritoneum of diabetics. Mechanisms responsible for these alterations may include the excess production, reduced degradation, and/or chemical modification of ECM proteins. These effects may be the result of direct or indirect actions of high glucose concentrations. This article reviews our state of knowledge on the effects that diabetes-like conditions exert on the cells responsible for ECM production as well as relevant experimental and clinical data.

Long-standing diabetes can result in the development of cardiomyopathy, which can be accompanied by myocardial fibrosis. Although exposure of cultured kidney and skin fibroblasts to high glucose (HG) concentration is known to increase collagen synthesis, little is known about cardiac fibroblasts (CFs). Therefore, we determined the influence of HG conditions on CF functions and the effects of losartan and vitamin E in these responses. We cultured rat CFs in either normal glucose (NG; 5.5 mM) or HG (25 mM) media and assessed changes in protein and collagen synthesis, matrix metalloproteinase (MMP) activity, and levels of mRNA for ANG II type 1 (AT(1)) receptors. Results indicate that HG-level CFs synthesized more protein and collagen, and these effects were not due to changes in osmotic pressure. The addition of ANG II stimulated protein and collagen synthesis in NG-concentration but not HG-concentration CFs. Interestingly, losartan pretreatment blocked the HG- or ANG II-induced increases in both protein and collagen synthesis. HG or ANG II decreased total MMP activity. Decreases in MMP activity were blocked by losartan. AT(1) mRNA levels were upregulated with HG concentration. Vitamin E pretreatment blocked the effects of HG on total protein synthesis and stimulated MMP activity. Results suggest that HG levels may promote fibrosis by increasing CF protein and collagen synthesis and decreasing MMP activity. HG levels may cause these effects via the upregulation of AT(1) receptors, which can be blocked by losartan. However, vitamin E can alter HG concentration-induced changes in CF functions independently of AT(1) mRNA levels.

1. Metabolic syndrome (MS) is one of the greatest public health problems in Mexico, where more than 75% of adults in urban populations are overweight or obese. Metabolic syndrome has several comorbidities, which result in a high cardiometabolic risk. 2. Some of the vasopathogenic phenomena in MS are caused by nitroxidant stress, secondary to cardiometabolic dysfunction. 3. The action of metformin to diminish or control MS remains a matter of debate. 4. In the present study, 60 patients with at least three diagnostic criteria for MS were divided into two groups. Both groups received similar dietary counselling, but one group was given 850 mg metformin daily. 5. The variables assessed were body mass index, waist circumference, systolic and diastolic blood pressures (SBP and DBP, respectively), total cholesterol (TC), high- and low-density lipoprotein-cholesterol, triglycerides (TG), fasting glucose, nitroxidant metabolites (free carbonyls, malondialdehyde, dityrosines and advanced oxidative protein products (AOPP)), nitric oxide (NO), carotid vascular stiffness, carotid intima-media thickness (IMT) and C-reactive protein (CRP). 6. After 1 year follow up, both groups reported weight loss, as well as decreases in waist circumference, SBP and DBP. 7. Patients on metformin exhibited reductions in TC and IMT and there were marked changes in nitroxidation: levels of carbonyls, dityrosines and AOPP were reduced, whereas those of NO were increased, indicating better endothelial function. In addition, in patients given metformin, CRP levels decreased. 8. In conclusion, metformin has a considerable beneficial effect on nitroxidation, endothelial function and IMT in patients with MS.

This study assessed the effect of 3 lipid-lowering therapies on the reduction of the carotid intima-media thickness (IMT) in high-risk coronary Mexican patients. The study was a randomized, comparative, and open clinical trial. Ninety high-risk coronary patients were allocated to 3 groups: pravastatin 40 mg, simvastatin 40 mg, and simvastatin 20 mg and ezetimibe 10 mg initially. If the therapeutic goals were not attained (<100 mg/dL of low-density lipoprotein cholesterol [LDL-C] for type C and <70 mg for type D), patients in group 1 received pravastatin 40 mg and ezetimibe 10 mg, group 2 received simvastatin 80 mg, and group 3 received simvastatin 40 mg and ezetimibe 10 mg. The primary endpoint was the change of IMT over the course of 1 year. The secondary endpoints were changes in LDL-C and in high sensitive C-reactive protein (CRPhs). The overall baseline IMTs generated by combining measurements in the internal carotid artery were 1.33+/-0.32 mm, 1.30+/-0.11 mm, and 1.23+/-0.28 mm for groups 1, 2, and 3, respectively. After 1 year, IMT values were 0.93+/-0.13 mm, 0.90+/-0.11 mm, and 0.92+/-0.01 mm for groups 1, 2, and 3, respectively. At the end of the study, LDL-C levels were 48+/-41, 45+/-37, and 48+/-31 in groups 1, 2, and 3, respectively. No significant differences were observed in CRP, high-density lipoprotein cholesterol, triglycerides, blood pressure, and body mass index, among the groups. This study is one of the first providing evidence that dual therapy has a beneficial effect on a surrogate marker of atherosclerosis.

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