Metabolic syndrome: maladaptation to a modern world

Alteraciones electrofisiológicas en el músculo auricular de rata con síndrome metabólico

El estilo de vida actual ha aumentado la prevalencia de Síndrome Metabólico (SM) el cual se ha relacionado con la arritmia más común a nivel mundial: la fibrilación auricular. En un modelo de rata con SM se han reportado cambios en el nodo senoauricular, sin embargo, el papel del músculo auricular en esta patología aún sigue sin conocerse. El objetivo de este trabajo es determinar si el SM genera arritmias supraventriculares en un modelo de rata y su relación con alteraciones en la morfología del potencial de acción auricular. Metodología: se utilizaron ratas Wistar macho a las cuales se indujo SM. Se midieron parámetros metabólicos, morfométricos, se registró el electrocardiograma (ECG) in vivo y potenciales de acción auriculares (PA) en una preparación de tejido aislado en donde se midió la excitabilidad. Resultados: en los animales del grupo SM se observaron alteraciones en el ECG como onda P bifásica y onda P mellada relacionado con la disminución en la duración del PA durante la repolarización en endocardio de la aurícula derecha y epicardio de aurícula izquierda, también se observaron cambios transmurales en la duración del PA en ambas aurículas y un desplazamiento hacia la derecha en la gráfica de excitabilidad en los registros del grupo SM.  Concusiones:  el SM remodela la actividad eléctrica supraventricular ya que modifica la heterogeneidad transmural de las aurículas aumentando la excitabilidad. Se propone que estos cambios contribuyen a la generación y mantenimiento de arritmias supraventriculares.

Novel Aspects in Inhibiting Pancreatic Lipase with Potential New Compound from Nutmeg in Connection with Obesity - In Vitro, In Silico, In Vivo and Ex Vivo Studies

Obesity is now considered a "new world syndrome" because it is affecting developed and developing nations in all classes of people. Pancreatic lipase (PL) is the key enzyme for absorption of dietary lipids. Excessive consumption of cafeteria foods leads to obesity. Nutmeg is being used as a spice and it has many medicinal values. We aimed to see whether nutmeg could be used as a potential source of new lipase inhibitors and to explore its molecular mechanism in obesity. An in vitro study, which was performed to check its anti-lipase activity, showed a potent lipase inhibition (66.24%). A liquid chromatography-mass spectrometry (LC-MS) analysis was carried out to identify new compounds, and tetrahydrofuran (THF) with MW 536 at RT 15.2 min was isolated. A molecular docking study, that was carried out to check the interaction between THF and PL, found a PL inhibitory action of tetrahydrofuran. A further in vivo study was conducted to see PL inhibition. The percentage of fecal fat was higher in nutmeg treated rats. The size and number of adipose tissue fat cells were also decreased after treatment with nutmeg extract, which pointed to the inhibition of PL by the newly identified compound, THF. These four different types of studies suggested that nutmeg could potentially inhibit pancreatic lipase.

Redox changes in obesity, metabolic syndrome, and diabetes

"Life is an instantaneous encounter of circulating matter and flowing energy" (Jean Giaja, Serbian physiologist), is one of the most elegant definitions not only of life but the relationship of redox biology and metabolism. Their evolutionary liaison has created inseparable yet dynamic homeostasis in health, which, when disrupted, leads to disease. This interconnection is even more pertinent today, in an era of increasing metabolic diseases of epidemic proportions such as obesity, metabolic syndrome, and diabetes. Despite great advances in understanding the molecular mechanisms of redox and metabolic regulation, we face significant challenges in preventing, diagnosing, and treating metabolic diseases. The etiological association and temporal overlap of these syndromes present significant challenges for the discrimination of appropriate clinical biomarkers for diagnosis, treatment, and outcome prediction. These multifactorial, multiorgan metabolic syndromes with complex etiopathogenic mechanisms are accompanied by disturbed redox equilibrium in target tissues and circulation. Free radicals and reactive species are considered both a causal factor and a consequence of disease status. Thus, determining the subtypes and levels of free radicals and reactive species, oxidatively damaged biomolecules (lipids, proteins, and nucleic acids) and antioxidant defense components as well as redox-sensitive transcription factors and fluxes of redox-dependent metabolic pathways will help define existing and establish novel redox biomarkers for stratifying metabolic diseases. This review aims to discuss diverse redox/metabolic aspects in obesity, metabolic syndrome, and diabetes, with the imperative to help establish a platform for emerging and future redox-metabolic biomarkers research in precision medicine. Future research warrants detailed investigations into the status of redox biomarkers in healthy subjects and patients, including the use of emerging 'omic' profiling technologies (e.g., redox proteomes, lipidomes, metabolomes, and transcriptomes), taking into account the influence of lifestyle (diet, physical activity, sleep, work patterns) as well as circadian ~24h fluctuations in circulatory factors and metabolites.

The Role of Metformin in Metabolic Disturbances during Pregnancy: Polycystic Ovary Syndrome and Gestational Diabetes Mellitus

Maintenance of gestation implicates complex function of multiple endocrine mechanisms, and disruptions of the global metabolic environment prompt profound consequences on fetomaternal well-being during pregnancy and postpartum. Polycystic Ovary Syndrome (PCOS) and gestational diabetes mellitus (GDM) are very frequent conditions which increase risk for pregnancy complications, including early pregnancy loss, pregnancy-induced hypertensive disorders, and preterm labor, among many others. Insulin resistance (IR) plays a pivotal role in the pathogenesis of both PCOS and GDM, representing an important therapeutic target, with metformin being the most widely prescribed insulin-sensitizing antidiabetic drug. Although traditional views neglect use of oral antidiabetic agents during pregnancy, increasing evidence of safety during gestation has led to metformin now being recognized as a valuable tool in prevention of IR-related pregnancy complications and management of GDM. Metformin has been demonstrated to reduce rates of early pregnancy loss and onset of GDM in women with PCOS, and it appears to offer better metabolic control than insulin and other oral antidiabetic drugs during pregnancy. This review aims to summarize key aspects of current evidence concerning molecular and epidemiological knowledge on metformin use during pregnancy in the setting of PCOS and GDM.

Pathophysiological domains underlying the metabolic syndrome: an alternative factor analytic strategy

PURPOSE

Factor analysis (FA) has become part and parcel in metabolic syndrome (MBS) research. Both exploration- and confirmation-driven factor analyzes are rampant. However, factor analytic results on MBS differ widely. A situation that is at least in part attributable to misapplication of FA. Here, our purpose was (i) to review factor analytic efforts in the study of MBS with emphasis on misusage of the FA model and (ii) to propose an alternative factor analytic strategy.

METHODS

The proposed factor analytic strategy consists of four steps and confronts weaknesses in application of the FA model. At its heart lies the explicit separation of dimensionality and pattern selection and the direct evaluation of competing inequality-constrained loading patterns. A high-profile MBS data set with anthropometric measurements on overweight children and adolescents is reanalyzed using this strategy.

RESULTS

The reanalysis implied a more parsimonious constellation of pathophysiological domains underlying phenotypic expressions of MBS than the original analysis (and many other analyses). The results emphasize correlated factors of impaired glucose metabolism and impaired lipid metabolism.

CONCLUSIONS

Pathophysiological domains underlying phenotypic expressions of MBS included in the analysis are driven by multiple interrelated metabolic impairments. These findings indirectly point to the possible existence of a multifactorial etiology.

Male-line transgenerational responses in humans

Genomic imprinting establishes the principle of epigenetic marks placed in one generation influencing gene expression in the next generation. This led to speculation that epigenetic gametic inheritance might underlie a form of transgenerational adaptation to major environmental challenges, such that exposures in one generation correlate with outcomes in the next generation(s). An ongoing collaboration between Umeå University, Sweden and the Avon Longitudinal Study of Parents and Childhood, Bristol University, UK has documented transgenerational correlations between food supply during the early life of the paternal grandparents and the grandchild's longevity, including associations with cardiovascular and diabetic deaths, and correlations between the onset of paternal smoking in mid-childhood and the body mass index of future sons. Whilst the mediating molecular mechanism(s) is unknown, the sex-specific transmission patterns and exposure-sensitive periods suggest a pre-evolved transgenerational response mechanism.

Renin angiotensin system polymorphisms in patients with metabolic syndrome (MetS)

BACKGROUND

The genes associated with hypertension could be genetic risk factors for metabolic syndrome (MetS).

AIM

To determine the frequency of M235T and T174M-AGT, I/D-ACE and A1166C-AGTR1 in hypertensive patients with MetS and to evaluate the relationship between these polymorphisms and central obesity and dyslipidemia, respectively.

MATERIALS AND METHODS

We performed AGT, AGTR1 and ACE genotyping in 56 hypertensive women (24 with MetS) and 71 normotensive women using PCR-RFLP methods and PCR, respectively.

RESULTS

Hypertensive patients carrying the mutated TT235, MM174 and DD genotypes had an 1.53 (p=0.56), 1.78 (p=0.52) and 1.28 (p=0.78)-fold increased risk to develop MetS. Hypertensive carriers of both mutated TT235 and MM174 or TT235 and D/D or TT235 and CC+AC genotypes had an 8.15 (p=0.04), 4.83 (p=0.04) and 10.53 (p=0.05)-fold increased risk to develop MetS. Hypertensive patients with MetS and TT, D/D or CC genotypes had higher body mass index compared to hypertensive patients without MetS (p</=0.05 for all the genotypes). Hypertensive patients with MetS and TT235, MM174, D/D or CC1166 genotypes had higher triglyceride levels, lower HDL-cholesterol levels and higher waist circumference compared to hypertensive patients without MetS (p</=0.05, except for the association between CC1166 and HDL-cholesterol level).

CONCLUSIONS

The effect of the T174M, I/D and A1166C polymorphisms on MetS may depend on the M235T polymorphism. Among hypertensive subjects with MetS, the presence of TT235, MM174, DD and CC1166 genotypes could be a risk factor for central obesity and dyslipidemia.

Insulin resistance/hyperinsulinemia and reproductive disorders in infertile women

Obesity, which disturbs lipid and glucose metabolism, is a recent medical concern. It threatens human health and also has adverse effects on reproductive functions by causing insulin resistance/hyperinsulinemia, especially in women with polycystic ovary syndrome (PCOS). For PCOS patients to prevent these adverse effects, it is important to take into account improving their lifestyles by exercise and proper diets. The relationship between insulin resistance/hyperinsulinemia and reproductive disorders should be understood as fully as possible in order to provide effective treatment. It is well known that insulin resistance and compensatory hyperinsulinemia can be triggered by obesity with visceral fat accumulation. Hyperinsulinemia affects granulosa cells in small follicles and theca cells. This condition induces early response to luteinizing hormones on granulosa cells of small follicles and causes premature differentiation of these cells, which eventually results in anovulation. For improvement of anovulation because of hyperinsulinemia, insulin-sensitizing agents (biguanide and thiazolidinedione derivatives) are useful. Hyperinsulinemia may adversely affect the endometrial functions and environment, and evoke implantation disturbance. Treatment with an insulin-sensitizing agent (metformin) improves the levels of glycodelin, insulin-like growth factor binding protein 1, and blood flow in spiral arteries during the peri-implantation period. It supports endometrial function, improves the endometrial environment, and facilitates embryo implantation. The rate of early pregnancy loss during the first trimester is 30-50% in women with PCOS, which is threefold higher than for normal women. Metformin treatment improves the levels of insulin, the homeostasis model assessment for insulin resistance, and plasminogen activator inhibitor activity, and decreases early pregnancy loss. It goes without saying that lifestyle change is fundamental for improving reproductive performance in addition to treatment with insulin-sensitizing agents.

The metabolic syndrome in patients on peritoneal dialysis: prevalence and influence on cardiovascular morbidity

The metabolic syndrome (MS) is a multi-factorial disorder which includes a main risk factors associated with the development of cardiovascular, neurologic, renal and endocrine diseases, especially type 2 diabetes. This study has been conducted to estimate the prevalence of the MS in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and its association with cardiovascular morbidity. The study included 37 patients (25 type 2 diabetic patients and 12 non-diabetic patients), who had been on peritoneal dialysis for > 3 months. At the beginning of CAPD treatment (baseline) and at the end of follow-up, we measured: body mass index (BMI), blood pressure, fasting blood glucose, triglycerides and high-density lipoprotein cholesterol (HDLC) and defined the prevalence of the MS using the modified National Cholesterol Education Program (NCEP; Adult Treatment Panel III) for peritoneal dialysis patients. The overall prevalence of the MS was 89.2%. The metabolic syndrome was estimated in all (100%) type 2 diabetic patients (vs. 60% patients on the beginning of CAPD treatment). In non-diabetic peritoneal patients, the MS was estimated in 50% cases, according to 33.3% at the beginning CAPD treatment. Development of the MS was significantly higher in the type 2 diabetic patients in compared with non-diabetic patients until the end of follow-up examination (p=0.0005). The prevalence of LVH in type 2 diabetic patients with the MS was significantly higher (p=0.002) than in non-diabetic peritoneal patients with the MS. We didn't found statistical significantly difference in the prevalence of ischemic heart disease between this two category of peritoneal dialysis patients (p=0.076). The results indicate that the metabolic syndrome is presented in high percentage in peritoneal dialysis patients, and it's also important risk factor of high cardiovascular morbidity rate in these patients, especially in type 2 diabetic patients.

The prediction of major outcomes of type 1 diabetes: a 12-year prospective evaluation of three separate definitions of the metabolic syndrome and their components and estimated glucose disposal rate: the Pittsburgh Epidemiology of Diabetes Complications Study experience

OBJECTIVE

The metabolic syndrome has been shown to confer an increased risk of cardiovascular disease in both the general and type 2 diabetic populations, but few studies have assessed the metabolic syndrome in type 1 diabetic patients. In a type 1 diabetic cohort, we assessed the prevalence and value of the metabolic syndrome in improving the prediction of major complication outcomes compared with its components and a surrogate measure of insulin resistance, estimated glucose disposal rate (eGDR).

RESEARCH DESIGN AND METHODS

A total of 514 (78%) subjects participating in the Pittsburgh Epidemiology of Diabetes Complications Study with complete 12-year follow-up clinical data were classified by baseline metabolic syndrome status according to three definitions: those of the National Cholesterol Education Program Adult Treatment Panel III (modified by the American Heart Association), the International Diabetes Federation (IDF), and the World Health Organization (WHO). The complication outcomes included coronary artery disease, renal failure, diabetes-related death, and the aggregate of these three major outcomes of diabetes (MOD).

RESULTS

Metabolic syndrome prevalence ranged from 8% (IDF) to 21% (WHO). All definitions showed reasonable specificity (> or = 83%) for each outcome, while the WHO definition had the highest sensitivity for all outcomes except renal failure, for which eGDR was most sensitive. However, the components of each definition predicted better than the overall syndrome. Microalbuminuria was clearly the strongest predictor of all individual measures, yielding hazard ratios of 9 and 6 for mortality and MOD, respectively.

CONCLUSIONS

Though the three metabolic syndrome classifications predict major complication outcomes in type 1 diabetes, their individual components predict better. Of the variables studied, including HbA1, microalbuminuria appears to be the best single predictor of MOD.

Moxonidine improves glycaemic control in mildly hypertensive, overweight patients: a comparison with metformin

AIM

To compare the effects of moxonidine and metformin on glycaemic control in patients with impaired glucose tolerance and signs of the metabolic syndrome.

METHODS

A multicentre, prospective, randomized, open-label study design was adopted with blinded endpoint evaluation. Patients > or =40 years old, with impaired glucose tolerance (or diabetes mellitus treated with diet alone) and a body mass index (BMI) of at least 27 kg/m2 were treated twice daily with moxonidine 0.2 mg or metformin 500 mg for 16 weeks. Oral glucose tolerance test (OGTT) was performed at baseline and end-of-study; plasma insulin and plasma glucose levels were measured at 0, 60, 120 and 180 min after administration.

RESULTS

With regard to effects on insulin [mean area under the curve (AUC) for insulin], the primary efficacy endpoint of the study, both drugs did not show equivalence. On the contrary, in the per protocol (PP) population, moxonidine statistically significantly (p = 0.025) decreased the AUC for insulin from baseline in the PP population; for metformin, the treatment effect on insulin was a small, net increase resulting in a statistically significant between-group difference of 16.2% (95% CI = 0.1-35.0). The change in mean insulin AUC was most marked in the subgroup of patients with higher sympathetic activity (heart rate >80 bpm). Mean fasting plasma glucose (FPG) levels and HbA1c levels were largely unchanged by moxonidine treatment but significantly decreased by metformin treatment. The difference between the groups was 14.7% (p = 0.0523) in the intent-to-treat (ITT) sample. By study end, both treatments had significantly increased the Matsuda Insulin Sensitivity Index (ISI) from baseline to a comparable extent: moxonidine by reducing plasma insulin after a glucose challenge, metformin by reducing FPG. BMI fell significantly in both groups and blood pressure normalized; both drugs were well tolerated.

CONCLUSIONS

Moxonidine improved insulin sensitivity in response to glucose challenge in patients with evidence of metabolic syndrome. This improvement resulted from a reduction in plasma insulin levels and was most marked in patients with high sympathetic drive at baseline. By enhancing insulin sensitivity, moxonidine treatment may help prevent the development of diabetes and thereby ameliorate the risk for cardiovascular disease.

Cognitive impairment in elderly women: the relative importance of selected genes, lifestyle factors, and comorbidities

BACKGROUND

A variety of factors contribute to the development of cognitive impairment in elderly people. Previous studies have focused upon a single or a few risk factors. In this study we assessed and compared the significance of a wide variety of potential risk factors for cognitive impairment in postmenopausal women.

METHODS

A total of 208 pairs of elderly women (mean age = 73.2 years) were examined in a cross-sectional case-control study. Each pair consisted of a case (with impaired cognition) and a control subject matched by age and educational status. Cognitive functions were determined using a modified version of the Blessed test. Participants were also subjected to a general clinical examination and they were interviewed to collect information on lifestyle practices and comorbid disorders. Genotypes for the apolipoprotein E (APOE) epsilon4, catechol-O-methyltransferase (COMT) Val/Met, and brain-derived neurotropic growth factor (BDNF) Val/Met polymorphisms were determined. Data were analyzed by conditional logistic regression.

RESULTS

We identified a set of risk factors for age-related cognitive impairment. A statistical model for assessment of the importance of these factors was constructed. The factors in this model were physical exercise (odds ratio [OR] = 0.50, 95% confidence interval [CI] = 0.32-0.78), regular alcohol consumption (OR = 0.49, 95% CI = 0.29-0.83), metabolic syndrome (OR = 2.83, 95% CI = 1.26-6.39), depression (OR = 3.24, 95% CI = 1.28-8.22), and the APOE epsilon4 allele (OR = 1.76, 95% CI = 1.09-2.83). Also COMT genotype was present as a risk factor in the statistical model (p = 0.08).

CONCLUSIONS

Lifestyle risk factors, comorbid disorders, and genetic factors contribute to development of age-related cognitive impairment. The two former groups of risk factors appear to be particular important in this respect.

The great weight gain experiment, accelerators, and their implications for autoantibodies in diabetes

Perspective on the paper by Reinehr et al (see page 473)