Insulin resistance, hyperinsulinemia, and cardiovascular disease. The need for novel dietary prevention strategies

Relationship between early-onset stroke and triglyceride-glucose index among young Chinese adults

BACKGROUND

The triglyceride-glucose index (TyG index), an alternative indicator of peripheral insulin resistance (IR), is associated with cardiovascular disease (CVD) in the general population. The aim of this research was to determine the correlation between early-onset stroke and the TyG index among young Chinese adults.

METHODS

Participants (age ≤ 40 years) who attended their first physical examination in Kailuan General Hospital or its 11 subsidiary hospitals between 2006 and 2012 were enrolled. The subjects were divided into four equal points according to the quartile of the TyG index, with the lowest quartile (Q1) as the reference group. A Cox proportional hazard model was employed to assess the correlation between early-onset stroke incidence and the TyG index. Restricted cubic spline analysis was further conducted to examine nonlinear associations. The TyG index was calculated as Ln [Triglyceride (TG, mg/dL) × Fasting Blood Glucose (FBG, mg/dL)/2].

RESULTS

Overall, 35,999 subjects met the inclusion criteria. Their mean age was 30.8 ±  5.7 years, and 77.1% of subjects were males. During a median observation period of 11 years, 281 stroke events occurred (62 hemorrhagic strokes and 219 ischemic strokes). Compared to the Q1 group (as the lowest group), subjects in groups Q2-Q4 had significantly higher risks of early-onset stroke (P < 0.05) after adjustment for relevant confounders in the Cox proportional hazards model. Similar results were consistent with ischemic stroke. However, no significant associations were observed between the risk of hemorrhage and the baseline TyG index. The restricted cubic splines revealed that the risk of stroke progressively increased with a high TyG index ≥ 8.41.

CONCLUSIONS

The TyG index may be a major risk factor for early-onset stroke among young Chinese adults. A TyG index ≥ 8.41 can be used as an indicator for screening high-risk stroke groups.

Functional food ingredients as adjunctive therapies to pharmacotherapy for treating disorders of metabolic syndrome

Abstract Information regarding the use of functional foods and nutraceuticals (FFN) in combating disease is rarely communicated to health care practitioners as medicinal strategies for patients. Metabolic syndrome (MetS) is an ideal paradigm for demonstrating the therapeutic properties of FFN. Encompassing multiple etiologies, including atherogenic dyslipidemia, insulin resistance, and hypertension, MetS affects over a third of American adults. However, as disease-related risk factors accumulate over time, guidelines for treating disorders of MetS progressively de-emphasize the use of FFN. Using marine omega-3 fatty acids, plant sterols, fiber, and tomato extract as examples, the purpose of this review is to endorse FFN as long-term adjunctive therapies to pharmaceutical treatment for disorders and risk factors for MetS. An additional goal is to compare physiological and molecular targets of FFN against corresponding prescription medications. Results reveal that FFN are viable treatment strategies for disorders of MetS, complementing pharmacological interventions by targeting and improving the biological processes that foster the development of disease. Thus, efficacious FFN therapies should be emphasized throughout all stages of treatment as adjuncts to pharmacotherapy for disorders of MetS. Accordingly, new developments in FFN research must be implemented into clinical guidelines with the prospect of improving disease prognoses as accessories to prescription medications.

Metabolic syndrome as a cardiovascular disease risk factor: patients evaluated in primary care

To estimate the prevalence of metabolic syndrome (MS) in a population receiving attention in primary care centers (PCC) we selected a random cohort of ostensibly normal subjects from the registers of 5 basic-health area (BHA) PCC. Diagnosis of MS was with the WHO, NCEP and IDF criteria. Variables recorded were: socio-demographic data, CVD risk factors including lipids, obesity, diabetes, blood pressure and smoking habit and a glucose tolerance test outcome. Of the 720 individuals selected (age 60.3 +/- 11.5 years), 431 were female, 352 hypertensive, 142 diabetic, 233 pre-diabetic, 285 obese, 209 dyslipemic and 106 smokers. CVD risk according to the Framingham and REGICOR calculation was 13.8 +/- 10% and 8.8 +/- 9.8%, respectively. Using the WHO, NCEP and IDF criteria, MS was diagnosed in 166, 210 and 252 subjects, respectively and the relative risk of CVD complications in MS subjects was 2.56. Logistic regression analysis indicated that the MS components (WHO set), the MS components (IDF set) and the female gender had an increased odds ratio for CVD of 3.48 (95CI%: 2.26-5.37), 2.28 (95%CI: 1.84-4.90) and 2.26 (95%CI: 1.48-3.47), respectively. We conclude that MS and concomitant CVD risk is high in ostensibly normal population attending primary care clinics, and this would necessarily impinge on resource allocation in primary care.

Excess catecholamine syndrome. Pathophysiology and therapy

In addition to genetic factors, lifestyle has a predominant influence on primary hypertension and noninsulin-dependent diabetic mellitus (NIDDM). We initiated studies using radiotelemetry for characterizing molecular events linked with excess calorie intake and psychologic stress. An increased calorie intake was associated with raised (p < 0.05) systolic and diastolic blood pressure as well as heart rate independent of day-night cycle. Sympathetic activity was in excess when related to the unchanged motility. The hyperkinetic hypertension is expected to result in adverse remodeling of resistance vessels and to aggravate insulin resistance. To examine adverse effects of psychological stress, rats were subjected to intermittent food pellet feeding. Urinary catecholamines and cardiac norepinephrine stores were increased (p < 0.05). The depressed (p < 0.05) rate of Ca2+ uptake of sarcoplasmic reticulum is expected to contribute to cellular Ca2+ overload. These lifestyle influences strengthen the notion of an excess catecholamine syndrome which requires selective reduction of sympathetic outflow of the brain by I1-receptor agonists.

Hepatic insulin clearance increases after weight loss in obese children and adolescents

BACKGROUND

Obesity is a rapidly increasing health problem among US youth. Hyperinsulinemia is associated with obesity and has been found to be a contributory factor for the development of cardiovascular disease in the obese. It has been suggested that hyperinsulinemia of obesity is a result of increased insulin secretion caused by insulin resistance. However, it has been shown in adults that decreased hepatic insulin clearance (HIC) is the primary cause of hyperinsulinemia in this population.

METHODS

We studied 15 obese children and adolescents (11 F, 4 M; 8.6 to 18.1 years) before and 10 weeks after their enrollment in a multidisciplinary weight reduction program, which included a protein-sparing modified fast, a moderate intensity progressive exercise program, and a behavior-modification intervention.

RESULTS

All patients lost weight (P < 0.05). Measurements of immunoreactive insulin (IRI) and C-peptide reactivity (CPR) were performed before the program and at 10 weeks. IRI levels dropped significantly, whereas CPR levels did not change. CPR/IRI molar ratios, considered an indirect estimation of HIC, rose significantly after weight loss.

CONCLUSIONS

Our data suggest that hyperinsulinemia seen in obese children and adolescents is caused by decreased HIC. The cause for this decrease remains unknown, but it is reversible upon weight loss.

Profactor-H (elevated circulating insulin): the link to health risk factors and diseases of civilization

We propose the term Profactor-H for chronic elevated circulating insulin. Profactor-H is common in atherosclerosis, essential hypertension, non-insulin dependent diabetes mellitus, some forms of obesity, some forms of cancer, cardiovascular disease, peripheral vascular disease and some forms of stroke. Profactor-H appears to be the central pathophysiologic consideration in the etiology of many diseases and health risk factors. Profactor-H's impact depends on genetic predisposition, frequency consumption of refined simple and complex carbohydrates, deficiency in dietary chromium, sedentary life style and stresses of modern day living. In many obese individuals, Profactor-H disturbs metabolic balance, favoring anabolic metabolism, and is exacerbated through chronic insulin production and impairment of insulin action. This vicious cycle also appears to be common in many apparently healthy, non-obese individuals destined to develop health risks and diseases in response to long-term adverse consequences of Profactor-H. We believe that a four-pronged program which 1) reduces the daily frequency of carbohydrate consumption, particularly refined foods and simple sugars, 2) supplements the daily dietary intake of chromium, 3) encourages activity, and 4) reduces stress, will minimize the impact of Profactor-H and thereby reduce health risks and result in improved health.

Excess catecholamines and the metabolic syndrome: should central imidazoline receptors be a therapeutic target?

A sympathetic overactivity plays a major role in the pathogenesis of cardiovascular diseases in Westernized affluent societies. Of importance is an increased caloric intake and psychosocial stress which are associated with a raised central sympathetic outflow and unfavourable changes in metabolic parameters. Normalization of central sympathetic outflow could thus be a major therapeutic target. The newly developed antihypertensive drugs moxonidine and rilmenidine reduce the excitatory activity of neurons of the rostral ventrolateral medulla (RVLM) via binding to imidazoline receptors. Using radio telemetry, it is shown that, in contrast to the first generation centrally acting drug clonidine, moxonidine did not result in rebound of blood pressure after drug withdrawal in rats with spontaneous hypertension. In accordance, moxonidine is characterized by a low affinity for alpha-adrenoceptors and exhibits few side-effects. It is proposed that normalization of central sympathetic outflow represents a causal approach for improving crucial features of the metabolic syndrome.

Modification of myosin isozymes and SR Ca(2+)-pump ATPase of the diabetic rat heart by lipid-lowering interventions

To define metabolic influences on cardiac myosin expression and sarcoplasmic reticulum (SR) Ca(2+)-stimulated ATPase streptozotocin-diabetic rats were treated for 9-10 wk with etomoxir, an inhibitor of carnitine palmitoyl transferase I (CPT-1) and fatty acid synthesis, or an antilipolytic drug, acipimox. Etomoxir reduced myosin V3 of diabetic rats but did not normalize it. However, the high serum triglyceride, free-fatty acid and cholesterol concentrations in diabetic animals were greatly reduced. After bypassing the CPT-1 inhibition with a medium-chain fatty acid (miglyol) diet, the V3 contents and serum lipids were still reduced in the etomoxir-treated diabetic rats; V3 was also reduced in diabetic rats fed miglyol or treated with acipimox. Since low serum insulin or triiodothyronine concentrations in diabetic rats were not improved by these interventions but changes in V3 were correlated with those in triglyceride, free-fatty acid and cholesterol concentrations, it is likely that myosin may be influenced by some metabolic factors. To assess the role of adrenergic influences, diabetic rats (7-8 wk) were treated with an antisympathotonic drug, moxonidine, a beta-adrenoceptor blocking drug, propranolol, and a bradycardic drug, tedisamil. Myosin V3 was not reduced significantly in moxonidine-treated or propranolol-treated rats in comparison to untreated diabetic rats. Serum thyroid hormones and insulin were not altered, whereas triglycerides were reduced but not significantly by these antiadrenergic agents. Lowering serum lipids in diabetic rats by treatment with etomoxir, miglyol and acipimox increased the depressed SR Ca(2+)-stimulated ATPase activity. On the other hand, in diabetic rats treated with moxonidine, propranolol or tedisamil, the ATPase activity was not increased significantly. These results suggest that normalization of blood lipids is important for improving subcellular organelle function in diabetic hearts with impaired glucose utilization.