A lifetime on the hips: programming lower-body fat to protect against metabolic disease

Adherence to unhealthy diets is associated with altered frontal gamma-aminobutyric acid and glutamate concentrations and grey matter volume: preliminary findings

OBJECTIVES

Common mental disorders (CMD) are associated with impaired frontal excitatory/inhibitory (E/I) balance and reduced grey matter volume (GMV). Larger GMV (in the areas that are implicated in CMD-pathology) and improved CMD-symptomatology have been observed in individuals who adhere to high quality diets. Moreover, preclinical studies have shown altered neurometabolites (primarily gamma-aminobutyric acid: GABA and glutamate: GLU) in relation to diet quality. However, neurochemical correlates of diet quality and how these neurobiological changes are associated with CMD and with its transdiagnostic factor, rumination, is unknown in humans. Therefore, in this study, we examined the associations between diet quality and frontal cortex neuro-chemistry and structure, as well as CMD and rumination in humans.

METHODS

Thirty adults were classified into high and low diet quality groups and underwent 1H-MRS to measure medial prefrontal cortex (mPFC) metabolite concentrations and volumetric imaging to measure GMV.

RESULTS

Low (vs High) diet quality group had reduced mPFC-GABA and elevated mPFC-GLU concentrations, as well as reduced right precentral gyrus (rPCG) GMV. However, CMD and rumination were not associated with diet quality. Notably, we observed a significant negative correlation between rumination and rPCG-GMV and a marginally significant association between rumination and mPFC-GLU concentrations. There was also a marginally significant association between mPFC-GLU concentrations and rPCG-GMV.

DISCUSSION

Adhering to unhealthy dietary patterns may be associated with compromised E/I balance, and this could affect GMV, and subsequently, rumination.

Body Fat Distribution, Cardiometabolic Traits, and Risk of Major Lower-Extremity Arterial Disease in Postmenopausal Women

OBJECTIVE

To assess the relationship between body fat distribution and incident lower-extremity arterial disease (LEAD).

RESEARCH DESIGN AND METHODS

We included 155,925 postmenopausal women with anthropometric measures from the Women's Health Initiative who had no known LEAD at recruitment. A subset of 10,894 participants had body composition data quantified by DXA. Incident cases of symptomatic LEAD were ascertained and adjudicated through medical record review.

RESULTS

We identified 1,152 incident cases of LEAD during a median 18.8 years follow-up. After multivariable adjustment and mutual adjustment, waist and hip circumferences were positively and inversely associated with risk of LEAD, respectively (both P-trend < 0.0001). In a subset (n = 22,561) where various cardiometabolic biomarkers were quantified, a similar positive association of waist circumference with risk of LEAD was eliminated after adjustment for diabetes and HOMA of insulin resistance (P-trend = 0.89), whereas hip circumference remained inversely associated with the risk after adjustment for major cardiometabolic traits (P-trend = 0.0031). In the DXA subset, higher trunk fat (P-trend = 0.0081) and higher leg fat (P-trend < 0.0001) were associated with higher and lower risk of LEAD, respectively. Further adjustment for diabetes, dyslipidemia, and blood pressure diminished the association for trunk fat (P-trend = 0.49), yet the inverse association for leg fat persisted (P-trend = 0.0082).

CONCLUSIONS

Among U.S. postmenopausal women, a positive association of upper-body fat with risk of LEAD appeared to be attributable to traditional risk factors, especially insulin resistance. Lower-body fat was inversely associated with risk of LEAD beyond known risk factors.

Clinical Characteristics, Phenotype of Lipodystrophy and a Genetic Analysis of Six Diabetic Japanese Women with Familial Partial Lipodystrophy in a Diabetic Outpatient Clinic

Objective Our aim was to examine the clinical characteristics and phenotype of lipodystrophy of six diabetic Japanese women with partial lipodystrophy (PL) who received a genetic analysis at a diabetic outpatient clinic. Methods We screened for PL using dual energy X-ray absorptiometry (DEXA) and magnetic resonance imaging (MRI) among patients who had a reduced peripheral skinfold thickness at the diabetic outpatient clinic of Kusatsu General Hospital between August 2003 and August 2013. We performed a mutation analysis of candidate genes, including LMNA and PPARG, in two patients with PL and whole-exome sequencing in four patients with PL. Results We identified 15 patients with PL and performed a genetic analysis in 6 of them. They had no mutations in candidate genes known to be associated with familial partial lipodystrophy (FPLD). They all had near-complete loss of subcutaneous fat, particularly in the antero-lateral and posterior thigh region and the calf region. As almost all patients were characterized by fat loss in the lower limbs with abdominal fat accumulation, a high rate of positivity for a family history, diabetes, and an unknown genetic cause, we suspected they might have FPLD1. Some patients have shown relatively severe insulin resistance, while others have shown insulin deficiency. Four and one had severe atherosclerosis and liver cirrhosis, probably due to nonalcoholic steatohepatitis, respectively. Conclusion Almost all patients with PL identified in a diabetic outpatient clinic had subcutaneous fat loss in the lower limbs with excess truncal fat and might have had FPLD1.

Gray matter structural networks are associated with cardiovascular risk factors in healthy older adults

While recent 'big data' analyses discovered structural brain networks that alter with age and relate to cognitive decline, identifying modifiable factors that prevent these changes remains a major challenge. We therefore aimed to determine the effects of common cardiovascular risk factors on vulnerable gray matter (GM) networks in a large and well-characterized population-based cohort. In 616 healthy elderly (258 women, 60-80 years) of the LIFE-Adult-Study, we assessed the effects of obesity, smoking, blood pressure, markers of glucose and lipid metabolism as well as physical activity on major GM-networks derived using linked independent component analysis. Age, sex, hypertension, diabetes, white matter hyperintensities, education and depression were considered as confounders. Results showed that smoking, higher blood pressure, and higher glycated hemoglobin (HbA1c) were independently associated with lower GM volume and thickness in GM-networks that covered most areas of the neocortex. Higher waist-to-hip ratio was independently associated with lower GM volume in a network of multimodal regions that correlated negatively with age and memory performance. In this large cross-sectional study, we found selective negative associations of smoking, higher blood pressure, higher glucose, and visceral obesity with structural covariance networks, suggesting that reducing these factors could help to delay late-life trajectories of GM aging.

Subcutaneous fat transplantation alleviates diet-induced glucose intolerance and inflammation in mice

AIMS/HYPOTHESIS

Adipose tissue (AT) distribution is a major determinant of mortality and morbidity in obesity. In mice, intra-abdominal transplantation of subcutaneous AT (SAT) protects against glucose intolerance and insulin resistance (IR), but the underlying mechanisms are not well understood.

METHODS

We investigated changes in adipokines, tissue-specific glucose uptake, gene expression and systemic inflammation in male C57BL6/J mice implanted intra-abdominally with either inguinal SAT or epididymal visceral AT (VAT) and fed a high-fat diet (HFD) for up to 17 weeks.

RESULTS

Glucose tolerance was improved in mice receiving SAT after 6 weeks, and this was not attributable to differences in adiposity, tissue-specific glucose uptake, or plasma leptin or adiponectin concentrations. Instead, SAT transplantation prevented HFD-induced hepatic triacylglycerol accumulation and normalised the expression of hepatic gluconeogenic enzymes. Grafted fat displayed a significant increase in glucose uptake and unexpectedly, an induction of skeletal muscle-specific gene expression. Mice receiving subcutaneous fat also displayed a marked reduction in the plasma concentrations of several proinflammatory cytokines (TNF-α, IL-17, IL-12p70, monocyte chemoattractant protein-1 [MCP-1] and macrophage inflammatory protein-1β [ΜIP-1β]), compared with sham-operated mice. Plasma IL-17 and MIP-1β concentrations were reduced from as early as 4 weeks after transplantation, and differences in plasma TNF-α and IL-17 concentrations predicted glucose tolerance and insulinaemia in the entire cohort of mice (n = 40). In contrast, mice receiving visceral fat transplants were glucose intolerant, with increased hepatic triacylglycerol content and elevated plasma IL-6 concentrations.

CONCLUSIONS/INTERPRETATION

Intra-abdominal transplantation of subcutaneous fat reverses HFD-induced glucose intolerance, hepatic triacylglycerol accumulation and systemic inflammation in mice.