Type 2 diabetes mellitus is a risk factor for the development of hypertension in postmenopausal women

Rapamycin inhibits activation of AMPK-mTOR signaling pathway-induced Alzheimer's disease lesion in hippocampus of rats with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is strongly correlated with Alzheimer's disease (AD). Rapamycin has important uses in oncology, cardiology and transplantation medicine. This study aims to investigate effects of rapamycin on AD in hippocampus of T2DM rat by AMPK/mTOR signaling pathway.

METHODS

Morris water maze test was applied to evaluate the learning and memory abilities. The fasting plasma glucose (FBG), glycosylated haemoglobin, total cholesterol, triglyceride and serum insulin level were measured. RT-qPCR and Western blot analysis were performed to test expression of AMPK and mTOR. Immunohistochemistry was used to detect the Aβ deposition and immunoblotting to test the total tau, p-tau and Aβ precursor APP expressions.

RESULTS

After treated with rapamycin, T2DM rats and rats with T2DM and AD showed increased learning-memory ability, and decreased levels of FBG, glycosylated hemoglobin, total cholesterol, triglyceride and serum insulin, decreased expression of APP and p-tau, increased AMPK mRNA expression and p-AMPK and decreased Aβ deposition, mTOR mRNA expression and p-mTOR.

CONCLUSION

The study demonstrated that rapamycin reduces the risk of AD in T2DM rats and inhibits activation of AMPK-mTOR signaling pathway, thereby improving AD lesion in hippocampus of T2DM rats.

Diabetes mellitus, blood glucose and the risk of heart failure: A systematic review and meta-analysis of prospective studies

BACKGROUND AND AIM

The strength of the association between diabetes and risk of heart failure has differed between previous studies and the available studies have not been summarized in a meta-analysis. We therefore quantified the association between diabetes and blood glucose and heart failure in a systematic review and meta-analysis.

METHODS AND RESULTS

PubMed and Embase databases were searched up to May 3rd 2018. Prospective studies on diabetes mellitus or blood glucose and heart failure risk were included. A random effects model was used to calculate summary relative risks (RRs) and 95% confidence intervals (CIs). Seventy seven studies were included. Among the population-based prospective studies, the summary RR for individuals with diabetes vs. no diabetes was 2.06 (95% CIs: 1.73-2.46, I² = 99.8%, n = 30 studies, 401495 cases, 21416780 participants). The summary RR was 1.23 (95% CI: 1.15-1.32, I² = 78.2%, n = 10, 5344 cases, 91758 participants) per 20 mg/dl increase in blood glucose and there was evidence of a J-shaped association with nadir around 90 mg/dl and increased risk even within the pre-diabetic blood glucose range. Among the patient-based studies the summary RR was 1.69 (95% CI: 1.57-1.81, I² = 85.5%, p_{heterogeneity}<0.0001) for diabetes vs. no diabetes (n = 41, 100284 cases and >613925 participants) and 1.25 (95% CI: 0.89-1.75, I² = 95.6%, p_{heterogeneity}<0.0001) per 20 mg/dl increase in blood glucose (1016 cases, 34309 participants, n = 2). In the analyses of diabetes and heart failure there was low or no heterogeneity among the population-based studies that adjusted for alcohol intake and physical activity and among the patient-based studies there was no heterogeneity among studies with ≥10 years follow-up.

CONCLUSIONS

These results suggest that individuals with diabetes are at an increased risk of developing heart failure and there is evidence of increased risk even within the pre-diabetic range of blood glucose.

Diabetes mellitus, blood glucose and the risk of atrial fibrillation: A systematic review and meta-analysis of cohort studies

BACKGROUND

Diabetes and elevated blood glucose have been associated with increased risk of atrial fibrillation in a number of epidemiological studies, however, the findings have not been entirely consistent. We conducted a systematic review and meta-analysis to clarify the association.

MATERIAL AND METHODS

We searched the PubMed and Embase databases for studies of diabetes and blood glucose and atrial fibrillation up to July 18th 2017. Cohort studies were included if they reported relative risk (RR) estimates and 95% confidence intervals (CIs) of atrial fibrillation associated with a diabetes diagnosis, prediabetes or blood glucose. Summary RRs were estimated using a random effects model.

RESULTS

Thirty four studies were included in the meta-analysis of diabetes, pre-diabetes or blood glucose and atrial fibrillation. Thirty two cohort studies (464,229 cases, >10,244,043 participants) were included in the analysis of diabetes mellitus and atrial fibrillation. The summary RR for patients with diabetes mellitus versus patients without diabetes was 1.30 (95% CIs: 1.03-1.66), however, there was extreme heterogeneity, I² = 99.9%) and evidence of publication bias with Begg's test, p < 0.0001. After excluding a very large and outlying study the summary RR was 1.28 (95% CI: 1.22-1.35, I² = 90%, n = 31, 249,772 cases, 10,244,043 participants). The heterogeneity was mainly due to differences in the size of the association between studies and the results persisted in a number of subgroup and sensitivity analyses. The summary RR was 1.20 (95% CI: 1.03-1.39, I² = 30%, n = 4, 2392 cases, 58,547 participants) for the association between prediabetes and atrial fibrillation. The summary RR was 1.11 (95% CI: 1.04-1.18, I² = 61%, n = 4) per 20 mg/dl increase of blood glucose in relation to atrial fibrillation (3385 cases, 247,447 participants) and there was no evidence of nonlinearity, p_nonlinearity = 0.34.

CONCLUSIONS

This meta-analysis suggest that prediabetes and diabetes increase the risk of atrial fibrillation by 20% and 28%, respectively, and there is a dose-response relationship between increasing blood glucose and atrial fibrillation. Any further studies should clarify whether the association between diabetes and blood glucose and atrial fibrillation is independent of adiposity.

Hypertension and the risk of endometrial cancer: a systematic review and meta-analysis of case-control and cohort studies

A history of hypertension has been associated with increased risk of endometrial cancer in several studies, but the results have not been consistent. We conducted a systematic review and meta-analysis of case-control and cohort studies to clarify the association between hypertension and endometrial cancer risk. PubMed and Embase databases were searched up to 27^th of February 2016. Prospective and case-control studies which reported adjusted relative risk estimates and 95% confidence intervals of endometrial cancer associated with a hypertension diagnosis were included. Summary relative risks were estimated using a random effects model. Nineteen case-control studies and 6 cohort studies were included. The summary RR was 1.61 (95% CI: 1.41–1.85, I² = 86%) for all studies, 1.73 (95% CI: 1.45–2.06, I² = 89%) for case-control studies and 1.32 (95% CI: 1.12–1.56, I² = 47%) for cohort studies. The association between hypertension and endometrial cancer was weaker, but still significant, among studies with adjustment for smoking, BMI, oral contraceptive use, and parity, compared to studies without such adjustment. This meta-analysis suggest an increased risk of endometrial cancer among patients with hypertension, however, further studies with more comprehensive adjustments for confounders are warranted to clarify the association.

The role of cerebrovascular disease and the association between diabetes mellitus and dementia among aged medicare beneficiaries

OBJECTIVE

The aim of this study is to assess whether diabetes mellitus is associated with overall dementia and its subtypes (Alzheimer's disease and vascular dementia) among the elderly and to identify the role of cerebrovascular disease in the association between diabetes and dementia.

METHODS

In a retrospective cross-sectional study, 5160 community-dwelling and institutionalized Medicare beneficiaries aged 65 years or over without health maintenance organization enrollment from the Medicare Current Beneficiary Survey in 2010 were included. The International Classification of Diseases-9 codes were used to identify the outcome and independent variables from the Medicare claims. The key predictor was diabetes mellitus and the outcomes were overall dementia and its subtypes. Logistic regression was employed to assess the association between dementia and diabetes after adjusting for age, gender, race, education, income, smoking status, and Charlson Comorbidity Index.

RESULTS

After adjusting for potential confounders, diabetes mellitus was significantly associated with overall dementia (odds ratio [OR] = 1.42; 95% confidence interval [CI], 1.14-1.77), vascular dementia (OR = 1.29; 95% CI, 1.02-1.64), and Alzheimer's disease (OR = 1.51, 95% CI, 1.10-2.09). The OR decreased to 1.26 (95% CI, 1.01-1.58) for overall dementia, controlling for cerebrovascular disease. The associations between diabetes mellitus and vascular dementia (OR = 1.13, 95% CI, 0.89-1.44) and Alzheimer's disease (OR = 1.39, 95% CI, 1.00-1.92) were no longer statistically significant once cerebrovascular disease was controlled.

CONCLUSIONS

The association between diabetes mellitus and dementia is only partially mediated through cerebrovascular disease, suggesting that diabetes mellitus is associated independently with overall dementia among the elderly, but not with vascular dementia and Alzheimer's disease.

Hypertension in postmenopausal women: pathophysiology and treatment

Hypertension is the most common chronic disease in industrialized countries and represents the most common major cardiovascular risk factor after the fifth decade of life in both men and women. The prevalence of hypertension is lower in premenopausal women than men, whereas in postmenopausal women it is higher than in men. Mechanisms responsible for the increase in blood pressure are complex and multifactorial, including loss of estrogen, oxidative stress, endothelial dysfunction, modification in renin-angiotensin system spillover and sympathetic activation. In addition, postmenopausal hypertension can be considered an isolated disease, more typical of elderly women, or part of the metabolic syndrome, which is indeed more common in early postmenopausal women. In particular, metabolic syndrome may be considered a potentially unfavourable prognostic factor in hypertensive postmenopausal women, because it seems to worsen the severity of hypertension and reduce the capacity to respond to specific treatments. This article summarizes the different causes of postmenopausal hypertension and the specific treatment recommended by guidelines for this condition.

Hypertension alone or related to the metabolic syndrome in postmenopausal women

Cardiovascular risk is poorly perceived by women, especially during the peri- and postmenopausal period when susceptibility to cardiovascular events increases. Nevertheless in Europe, 55% of women versus 43% of men currently die of cardiovascular disease. Blood pressure is one of the most powerful and accurate determinants of cardiovascular status and risk. Despite its importance, hypertension is often underestimated and undiagnosed, especially in women. Various mechanisms are implicated to play a role in the blood pressure increase in women at the time of menopause. Hypertension can be considered an isolated disease, more typical of elderly women, or part of the metabolic syndrome, more frequent in early postmenopausal women. The metabolic syndrome, a clustering of lipid and nonlipid cardiovascular risk factors, is estimated to affect approximately 20-30% of the middle-aged population and its prevalence appears to be increasing in the worldwide population.

Metabolic Syndrome Affects Cardiovascular Risk Profile and Response to Treatment in Hypertensive Postmenopausal Women

Metabolic syndrome is increasingly recognized as an important cardiovascular risk factor in hypertension, but its influence on the cardiovascular risk profile in hypertensive postmenopausal women has not been studied. The aim of the present study was to investigate the impact of metabolic syndrome on the cardiovascular risk profile and the response to treatment. We enrolled 350 hypertensive postmenopausal women, 55±6 years of age (range 47 to 60 years of age). Patients were divided into 2 groups according to the presence of metabolic syndrome. Compared with those without, women with metabolic syndrome had higher waist circumference, body mass index, and levels of glucose, triglycerides, and HDL cholesterol, as would be expected, based on definition. In addition, patients with metabolic syndrome had a cardiovascular risk profile less favorable, characterized by a significantly higher highly sensitive C-reactive protein (2.2±0.6 versus 1.7±0.7 ng/L; P <0.01), a more compromised endothelial function (flow-mediated vasodilation 2.4±2.2 versus 4.4±2.5%; P =0.01), and a significantly higher left ventricular mass (44±15 versus 41±16 g/m 2.7 ). Also, antihypertensive treatment induced a more modest improvement of both endothelial dysfunction and subclinical inflammation in women with metabolic syndrome. The results of our study show that in postmenopausal women, there are 2 different forms of hypertension: that which is isolated, and that which is associated with metabolic syndrome. This last form is related to a more severe risk profile, and response to therapy is less favorable.

Approaches to prevention of cardiovascular complications and events in diabetes mellitus

Diabetes mellitus affects about 8% of the adult population. The estimated number of patients with diabetes, presently about 170 million people, is expected to increase by 50-70% within the next 25 years. Diabetes is an important component of the complex of 'common' cardiovascular risk factors, and is responsible for acceleration and worsening of atherothrombosis. Major cardiovascular events cause about 80% of the total mortality in diabetic patients. Diabetes also induces peculiar microangiopathic changes leading to diabetic nephropathy conducive to end-stage renal failure, and to diabetic retinopathy that may progress to vision loss and blindness. In terms of major cardiovascular events, coronary heart disease and ischaemic stroke are the main causes of morbidity and mortality in diabetic patients. Peripheral arterial disease frequently occurs, and is more likely to be conducive to critical limb ischaemia and amputation than in the absence of diabetes. Although there are a number of differences in the pathogenesis and clinical features of diabetic macroangiopathy and microangiopathy, these two entities often coexist and induce mutually worsening effects. Endothelial injury, dysfunction and damage are common starting points for both conditions. Causes of endothelial injury can be distinguished into those 'common' to nondiabetic atherothrombosis, such as hypertension, dyslipidaemia, smoking, hypercoagulability and platelet activation; and those more specific and in some cases 'unique' to diabetes and directly related to the metabolic derangement of the disease, such as (i) desulfation of glycosaminoglycans (GAGs) of the vascular matrix; (ii) formation of advanced glycation end-products (AGE) and their endothelial receptors (RAGE); (iii) oxidative and reductive stress; (iv) decline in nitric oxide production; (v) activation of the renin-angiotensin aldosterone system (RAAS); and (vi) endothelial inflammation caused by glucose, insulin, insulin precursors and AGE/RAGE. Prevention of major cardiovascular events with the antithrombotic agent aspirin (acetylsalicylic acid) is widely recommended, but reportedly underutilised in patients with diabetes. However, some data suggest that aspirin may be less effective than expected in preventing cardiovascular events and especially mortality in patients with diabetes, as well as in slowing progression of retinopathy. In contrast, a recent study found picotamide, a direct thromboxane inhibitor, to be superior to aspirin in diabetic patients. Clopidogrel was either equivalent or less active in diabetic versus nondiabetic patients, depending upon different clinical settings.Recent studies have shown that some GAG compounds are able to reduce micro- and macroalbuminuria in diabetic nephropathy, and hard exudates in diabetic retinopathy, but it is as yet unknown whether these agents also influence the natural history of microvascular complications of diabetes. Lifestyle changes and physical exercise are also essential in preventing cardiovascular events in diabetic patients. Available data on the control of the metabolic state and the main risk factors show that careful adjustment of blood sugar and glycated haemoglobin is more effective in counteracting microvascular damage than in preventing major cardiovascular events. The latter objective requires a more comprehensive approach to the whole constellation of risk factors both specific for diabetes and common to atherothrombosis. This approach includes lifestyle modifications, such as dietary changes and smoking cessation and the use of HMG-CoA reductase inhibitors (statins), which are able to correct the lipid status and to prevent major cardiovascular events independently of the baseline lipidaemic or cardiovascular status. Tight control of hypertension is essential to reduce not only major cardiovascular events but also microvascular complications. Among antihypertensive measures, blockade of the RAAS by means of ACE inhibitors or angiotensin II receptor antagonists recently emerged as a potentially polyvalent approach, not only for treating hypertension and reducing cardiovascular events, but also to prevent or reduce albuminuria, counteract diabetic nephropathy and lower the occurrence of new type 2 diabetes in individuals at risk.