Insulin resistance in young, lean male subjects with essential hypertension

Prevalence of nonalcoholic fatty liver disease and the related risk factors among healthy adults: A cross-sectional study in Chongqing, China

Background

Epidemiological characteristics of nonalcoholic fatty liver disease (NAFLD) in Chongqing, a west-central city of China, remain unclear. The objective of this study was to investigate the prevalence of NAFLD and the related risk factors among healthy adults for physical examination in Chongqing.

Methods

A total of 110,626 subjects were enrolled in the present study. Each of the participants underwent physical examination, laboratory measurements, and abdominal ultrasonography. The chi-square test was employed to compare differences in the NAFLD prevalence, and logistic regression analysis was used to estimate the odds ratio for risk factors of NAFLD.

Results

The prevalence of NAFLD in individuals in the population of Chongqing was 28.5%, and the prevalence in men (38.1%) was significantly higher than that in women (13.6%) (OR = 2.44; 95% CI: 2.31-2.58). NAFLD was more common in men aged 51-60 years and women over 60 years. Approximately 79.1% of the people with obesity and 52.1% of the people with central obesity had NAFLD. The prevalence of NAFLD in people with hypertension and cholelithiasis was 48.9 and 38.4%, respectively. Logistic regression showed that gender, age, body max index (BMI), central obesity, hypertension, impaired fasting glucose/diabetes mellitus (DM), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), hyperuricemia (HUA), alanine transaminase (ALT), and cholelithiasis were independently associated with the presence of NAFLD.

Conclusion

The prevalence of NAFLD among healthy adults in Chongqing was high. To improve the prevention and management of NAFLD, special attention should be paid to the factors associated with the presence of NAFLD, including higher BMI, higher waist circumference, higher blood glucose, hypertension, hypertriglyceridemia, hyperuricemia, cholelithiasis, and elevated ALT.

Cardiometabolic risk factors and early indicators of vascular dysfunction: a cross-sectional cohort study in South African adolescents

OBJECTIVES

Prevalence of child and adolescents' overweight and obesity in low- and middle-income countries has increased dramatically. Simultaneously, the incidence of pre-hypertension/hypertension is also increasing in children, which, in turn, predisposes these children to the risk of cardiovascular disease (CVD) in later life. The present study assessed cardiometabolic risk factors and early indicators of vascular dysfunction in adolescents from a low socio-economic rural area in South Africa.

DESIGN

Cross-sectional cohort study.

SETTING

The study was conducted in public schools in Mthatha, OR Tambo district municipality, Eastern Cape Province, South Africa.

PARTICIPANTS

A total of 244 adolescents (188 females) of African ancestry aged 13-16 years were enrolled.

PRIMARY AND SECONDARY OUTCOME MEASURES

Anthropometric and haemodynamic measures and pulse wave velocity (PWV) were related to overweight/obesity and hypertension. Blood markers of cardiometabolic syndrome were assessed as well as vascular function (via PWV).

RESULTS

One-third (33.0%) of the adolescents exceeded the age and sex-specific body mass index percentiles for overweight (≥85th) or obesity (>95th) with a prevalence of 61.1% pre-hypertensives in this group. Overweight/obesity and hypertension were associated with higher triglycerides (lean:overweight: 0.79<1.01 mmol/L; normotensive:hypertensive: 0.82<0.89 mmol/L). Fasting glucose was higher in hypertensive as compared to normotensive adolescents (4.85>4.69 mmol/L, p<0.05). PWV was elevated in 25.9% of the children and significantly correlated with asymmetric dimethylarginine and systolic blood pressure (p<0.001).

CONCLUSION

Overweight/obesity and hypertension show a high prevalence in rural South African youth. Almost half of the studied adolescents are at risk for developing CVD. The high association between cardiometabolic risk factors and PWV further suggests that hypertension in adolescents may promote the progression of CVD in adulthood. Early detection of those at risk and the implementation of preventive strategies in underprivileged young people is urgently needed to stop the progression of vascular damage and manifestation of CVD in rural African children.

Diet-Induced Hyperinsulinemia as a Key Factor in the Etiology of Both Benign Prostatic Hyperplasia and Essential Hypertension?

Benign prostatic hyperplasia and hypertension are common age-related comorbidities. Although the etiology of benign prostatic hyperplasia (BPH) is still largely unresolved and poorly understood, a significant age-independent association was found between BPH and hypertension, indicating a common pathophysiological factor for both diseases. It has previously been suggested that the development of essential hypertension may be related to diet-induced hyperinsulinemia. This study follows the question, whether BPH may develop due to the same mechanism, thereby explaining the well-known comorbidity of these 2 disorders. The scientific evidence presented shows that BPH and hypertension share the same pathophysiological changes, with hyperinsulinemia as the driving force. It further shows that significant dietary changes during human history cause disruption of a finely tuned metabolic balance that has evolved over millions of years of evolution: high-insulinemic food, typical of current “Western” diets, has the potential to cause hyperinsulinemia and insulin resistance, as well as an abnormally increased activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system, alterations that play a pivotal role in the pathogenesis of BPH and hypertension.

Blood pressure is associated with the presence and severity of nonalcoholic fatty liver disease across the spectrum of cardiometabolic risk

OBJECTIVES

To determine the relationship between clinically relevant blood pressure (BP) groups and nonalcoholic fatty liver disease (NAFLD) presence and severity especially in the milieu of other metabolic risk factors.

PATIENTS AND METHODS

From a Brazilian cohort of 5362 healthy middle-aged men and women who presented for yearly physical examination and testing, the cross-sectional relationship between BP categories and NAFLD was assessed. BP groups were categorized as normal, prehypertension (PHT), and hypertension (HTN) according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure classification. NAFLD was ultrasound diagnosed, excluding persons with alcohol consumption more than 20 g/day. NAFLD severity was estimated using the Fibrosis-4 (FIB-4) risk score.

RESULTS

The prevalence of NAFLD was 36.2%. Participants with NAFLD were older (mean 46 vs. 42 years, P < 0.001) and had elevated BMI (mean 29.0 vs. 24.7 kg/m, P < 0.001). The prevalence of NAFLD among persons with normal BP, PHT, and HTN was 16.5, 37.5, and 59.3%, respectively. In multivariate analyses, PHT and HTN were associated with elevated odds of NAFLD (PHT-adjusted odds ratio 1.3, 95% confidence interval 1.1, 1.6; HTN-adjusted odds ratio 1.8, 95% confidence interval 1.4-2.3) compared with normal BP. Among nonobese hypertensive patients, BP control (BP < 140/90 mmHg) was independently associated with 40% lower odds of prevalent NAFLD. Compared with hypertensive patients, both normotensive individuals and prehypertensive patients were more likely to have a low fibrosis risk (FIB-4 ≥ 1.3).

CONCLUSION

Prevalent NAFLD may be seen early in the development of hypertension, even in the absence of other metabolic risk factors. Controlling BP among nonobese hypertensive patients may be beneficial in preventing or limiting NAFLD.

The novel ATP-sensitive potassium channel opener iptakalim prevents insulin resistance associated with hypertension via restoring endothelial function

AIM

To investigate the effects of iptakalim on endothelial dysfunction induced by insulin resistance (IR) and to determine whether iptakalim improved IR associated with hypertension in fructose-fed rats (FFRs) and spontaneously hypertensive rats (SHRs).

METHODS

Human umbilical vein endothelial cells (HUVECs) were used for in vitro study. The levels of endothelial vasoactive mediators and eNOS protein expression were determined using radioimmunoassays, ELISAs, colorimetric assays or Western blotting. Sprague-Dawley rats were fed with a high-fructose diet. In both FFRs and SHRs, tail-cuff method was used to measure systolic blood pressure (SBP), and hyperinsulinemic- euglycemic clamp was used to evaluate IR states.

RESULTS

(1) Cultured HUVECs incubated with the PI3-kinase inhibitor wortmannin (50 nmol/L) and insulin (100 nmol/L) induced endothelial dysfunction characterized by significantly reduced release of NO and expression of eNOS protein, and significantly increased production of ET-1. Pretreatment with iptakalim (0.1-10 μmol/L) could prevent the endothelial dysfunction. (2) In FFRs, the levels of SBP, fasting plasma glucose and insulin were significantly elevated, whereas the glucose infusion rate (GIR) and insulin sensitive index (ISI) were significantly decreased, and the endothelium-dependent vascular relaxation response to ACh was impaired. These changes could be prevented by oral administration of iptakalim (1, 3, or 9 mg·kg(-1)·d(-1), for 4 weeks). The imbalance between serum NO and ET-1 was also ameliorated by iptakalim. (3) In 2-4 month-old SHRs (IR was established at the age of 4 months), oral administration of iptakalim (1, 3, or 9 mg·kg(-1)·d(-1), for 8 weeks) significantly ameliorated hypertension and increased the GIR to the normal level.

CONCLUSION

These results demonstrate that iptakalim could protect against IR-induced endothelial dysfunction, and ameliorate IR associated with hypertension, possibly via restoring the balance between NO and ET-1 signaling.