Obesity in the elderly: is faulty metabolism to blame?

Trends and Disparities in Colonic Diverticular Disease Hospitalizations in Patients With Morbid Obesity: A Decade-Long Joinpoint Analysis

Objective We aimed to describe epidemiologic trends in outcomes of colonic diverticular disease (CDD) hospitalizations in morbidly obese patients. Methods We searched the United States National Inpatient Sample databases from 2010 through 2019, obtained the incidence rate of morbid obesity (MO) among CDD hospitalizations, and used Joinpoint analysis to obtain trends in these rates adjusted for age and sex. Hospitalizations involving patients less than 18 years of age were excluded. Trends in mortality rate, mean length of hospital stay (LOS), and mean total hospital charge were analyzed. Multivariate regression analysis was used to obtain trends in adjusted mortality, mean LOS, and mean total hospital charge. Results We found an average annual percent change of 7.5% (CI = 5.5-9.4%, p < 0.01) in the adjusted incidence of MO among hospitalizations for CDD over the study period. We noted a 7.2% decline in mortality (p = 0.011) and a 0.1 days reduction in adjusted LOS (p < 0.001) over the study period. Hospitalizations among the middle-aged and elderly had adjusted odds ratios of 7.18 (95% CI = 2.2-23.3, p = 0.001) and 24.8 (95% CI = 7.9-77.9, p < 0.001), respectively, for mortality compared to those in young adults. The mean LOS was 0.29 days higher in females compared to males (p < 0.001). Conclusion The incidence of MO increased among CDD hospitalizations while mortality and mean LOS reduced over the study period. Outcomes were worse in older patients, with an increased mean LOS in females compared to males.

Beneficial Effect of Increased Tryptophan Intake on Its Metabolism and Mental State of the Elderly

The elderly often suffer from sleep disorders and depression, which contribute to mood disorders. In our previous work, we showed that elderly individuals with mood disorders had a lower intake of TRP and recommended a TRP-based dietary intervention to improve the mental state of such individuals. In this work, we assessed the impact of a TRP-rich diet on the mental state of, and TRP metabolism in, elderly individuals with mood disorders. Forty elderly individuals with depression and sleep disorders and an equal number of elderly subjects without mood disorders were enrolled in this study. TRP intake was evaluated with the nutrition calculator. Patients with mood disorders had a lower TRP intake than their normal counterparts and received a TRP-rich diet with TRP content of 25 mg per kilogram of the body per day for 12 weeks. The mental state was assessed before and after this dietary intervention with the Hamilton Depression Rating Scale (HAM-D) and the Insomnia Severity Index (ISI). At those times, urinary levels of TRP and its metabolites 5-hydroxyindoleacetic acid (5-HIAA), L-kynurenine (KYN), kynurenic acid (KYNA), and quinolinic acid (QA) were determined by liquid chromatography with tandem mass spectrometry and related to creatinine level. After TRP-based dietary intervention, the score of ISI and HAM-D decreased by more than half. A correlation analysis reveals that TRP, 5-HIAA, and KYNA might have anti-depressive action, while KYN and QA-pro-depressive. The levels of TRP, 5-HIAA, and KYNA in urine of mood disorder patients increased, while the levels of KYN and QA decreased. In conclusion, dietary consumption of adequate amount of tryptophan has a beneficial effect on mental health of the elderly with mood disorders and improves metabolism of this amino acid. Therefore, a TRP-enriched diet may be considered as a component of the treatment of elderly individuals with mood disorders.

Factors associated with nutrition risk among community-dwelling older adults in Thailand

This study was to investigate socio-demographic, chronic conditions and health factors associated with nutrition risk among Thai community-dwelling older adults. This was a cross-sectional study, involving 330 participants aged ≥ 60 years living in low-income suburban Chiang Mai, Northern Thailand. Of the 330 participants, 54.8% were at nutritional risk based on the Mini Nutritional Assessment. Multivariate analysis indicated factors significantly associated with nutritional risk were: aged ≥80 years (OR:8.59, 95% CI = 2.94-25.11), low income (OR: 2.35, 95% CI = 1.15-4.78), living alone (OR: 2.02, 95% CI = 0.20-0.78), moderate to severe pain (OR: 5.88, 95% CI = 2.30-15.02), dyslipidemia (OR: 5.12, 95% CI = 2.23-11.77), osteoarthritis (OR: 2.49, 95% CI = 1.14-5.48), poor physical performance (OR: 1.49, 95% CI = 1.70-3.15), and ≥1 fall in the previous year (OR: 2.22, 95% CI = 1.21-4.07). Results point to the need for multifactorial interventions to reduce risk for geriatric nutrition problems. Further studies are needed to determine effective solutions to the problem of malnutrition among older adults.

Quantity not composition of dietary fats represents the dominant contributor to experimental obesity: Relevance to human pathophysiology

Plant fats are low in saturated fats but high in unsaturated fats compared to animal fats, and are supposedly less obesogenic. This study compared the obesogenic effects of plant and animal derived fatty diets in Wistar rats. Rats of each gender were divided into three dietary (standard chow (SC), high fat diet rich in animal fat (HFDaf) and a high fat diet rich in plant fat (HFDpf)) groups of ten each and fed for 17 weeks. Anthropometric, Adiposity and nutritive variables were assessed using standard methods. Comparing HFDpf to HFDaf: Abdominal circumference (AC),initial feed intaken (IFI), final feed intake(FFI), final body weight (FBW), white adipose tissue (WAT) were increased but brown adipose tissue (BAT) decreased in male rats fed with HFDpf; also, there were increased body length, IFI, FFI but decreased AC, FBW, BAT in female rats fed with HFDpf. Comparing male to female rats: Thoracic circumference, IFI, FFI, energy intake were increased while Adiposity index decreased across diet groups in male rats; the AC, FBW increased while WAT, BAT decreased in HFDpf fed group, also, BAT was increased but AC, FBW decreased in HFDaf fed group in male rats. Palatability and high feed efficiency of consumed diets were more associated with obesogenic risk than just the level of saturation. Therefore, Obesogenic effects of fatty diets in both genders is more dependent on the quantity (amount) of fatty diet consumed than the dietary fat composition alone.

Trends in obesity prevalence among total hip arthroplasty patients and the effect on surgical outcomes, 2008-2016

INTRODUCTION

The prevalence of obesity continues to rise in parallel with demand for total hip arthroplasty (THA). This study aims to report obesity trends in primary THA and its effects on procedure outcomes in the United States, stratifying based on Body Mass Index (BMI).

METHODS

Primary THA procedures were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2008-2016). Patient demographic (including BMI), primary outcomes (death; serious morbidity), and secondary outcome variables were analyzed. Using BMI comparison groups (Obese: BMI > 30 [O]; Morbidly Obese: BMI > 40 [MO]) for case populations, univariate, propensity score-matched, and multivariate logistic regression analyses were performed.

RESULTS

The prevalence of obesity increased among primary THA (2008: 546/1200 [45.5%], 2016: 16,078/34,137 [47.1%]) cases. Data on 135,013 primary THA cases were analyzed. Propensity score-matched analyses demonstrated that both serious morbidity (O: OR = 0.73, p < 0.001; MO: OR = 0.84, p = 0.001) and frequency of discharges home (O: OR = 0.90, p < 0.001; MO: OR = 0.71, p < 0.001) were significantly reduced. Instead, long operative times (O: OR = 1.30, p < 0.001; MO: OR = 1.53, p < 0.001), readmission (O: OR = 1.27, p < 0.001; MO: OR = 1.49, p < 0.001), and reoperation (O: OR = 1.44, p < 0.001, MO: OR = 1.96, p < 0.001) were all significantly increased in both obese and morbidly obese cases. Death (OR = 0.29; p = 0.016) was decreased in the MO cohort, while length of stay (OR = 1.19, p = 0.004) was increased in the MO cohort.

CONCLUSION

Both obese and morbidly obese primary THA patient populations were associated with variably increased complication risks; morbidly obese patients had higher complication rates relative to obese patients. Orthopaedic surgeons should continue to consider obesity as a risk factor for THA complications. However, given similar functional outcomes and satisfaction levels as non-obese patients, denying patients THA surgery based on BMI alone may merit reconsideration.

Criterion Validity of Ultrasound Imaging: Assessment of Multifidi Cross-Sectional Area in Older Adults With and Without Chronic Low Back Pain

BACKGROUND AND PURPOSE

Ultrasound (US) imaging may be a cost-conscious alternative to magnetic resonance imaging (MRI), which is the criterion standard for muscle cross-sectional area (CSA) assessment. Within the trunk, when compared with MRI, US has been shown to be valid for assessing lumbar multifidi CSA in younger, asymptomatic individuals. To date, there are no studies validating US for multifidi CSA assessment in older adults or individuals with low back pain. Given age- and pain-related muscle changes, validation of US is needed in these populations. If valid for multifidi CSA assessment, US may be used to evaluate short-term changes in muscle size in response to exercise-based interventions among older adults. The primary objective of this study was to evaluate the validity of US for multifidi CSA assessment as compared with MRI in older adults with and without chronic low back pain (CLBP). The secondary objective was to determine whether a single US image was valid for assessment of multifidi CSA or whether the average of 3 US images should be recommended.

METHODS

Twenty community-dwelling older adults (ie, 10 with and 10 without CLBP), ages 60 to 85 years, were recruited. US images and MRI slices of multifidi muscle were obtained and L4 multifidi CSAs were measured. Intraclass correlation coefficients (ICCs) were calculated to assess agreement between MRI measures and a single US image and MRI measures and the average of 3 US images.

RESULTS AND DISCUSSION

ICC point estimates were excellent for older adults with CLBP for a single US image (ICCs = 0.90-0.97), but ICC point estimates for participants without CLBP ranged from fair to excellent (ICCs = 0.48-0.86). ICC point estimates for the average of 3 US images for both groups were better than for a single image (ICCs = 0.95-0.99).

CONCLUSIONS

For assessment of L4 multifidi CSA, US is a valid alternative to MRI for older adults with and without CLBP. However, limitations of US, such as the inability to quantify intramuscular fat, which may be increased with aging and CLBP, should be considered. CSA measurement of 3 US images, rather than a single image, is recommended.

Overweight in rural elderly: association with health conditions and quality of life

This study aimed to verify the association of overweight with functional disability, self-reported morbidities and quality of life (QoL) among rural elderly dwellers. This is a domestic and cross-sectional survey conducted in the rural region of a municipality of Southeast Brazil. Three hundred seventy non-overweight elderly people and 192 overweight elderly people were evaluated with the following tools: semi-structured; Katz and Lawton and scales; World Health Organization Quality of Life - BREF and World Health Organization Quality of Life Assessment for Older Adults. Overweight was associated with morbidities arthritis/osteoarthritis (p = 0.002), systemic arterial hypertension (p < 0.001), varicose veins (p = 0.009), heart problems (p = 0.028), diabetes mellitus (p = 0.001), cerebrovascular accident (p = 0.044) and urinary incontinence (p = 0.032). Overweight elderly had lower scores in the physical realm (p = 0.005) and higher scores in social relationships (p = 0.033) compared to those without this condition. Results point to the importance of monitoring the nutritional status of rural elderly to prevent comorbidities and improve the quality of life.

Anthropometric patterns of adiposity, hypertension and diabetes mellitus in older adults of Viçosa, Brazil: A population-based study

AIM

To identify anthropometric patterns of adiposity and estimate their association with hypertension and diabetes mellitus (DM) in older adults.

METHODS

A cross-sectional study with 537 older adults aged ≥60 years was carried out. Weight, height, and waist, hip and calf circumference were measured. The following indices were calculated: a body shape index, body roundness index, conicity index, body adiposity index, body mass index, waist-to-height ratio, waist-to-calf ratio, waist-to-hip ratio and waist-to-hip-to-height ratio. The anthropometric patterns of adiposity were obtained by factor analysis of principal components, and their association with hypertension and DM was identified by multiple Poisson regression with robust variance.

RESULTS

Two anthropometric patterns of adiposity were identified. Pattern 1 and 2 explained approximately 53% and 33% of the total variance, respectively, in both sexes. Pattern 1 indicated of global adiposity, and weight, body mass index and hip circumference were the variables most strongly correlated with this pattern in both sexes. Pattern 2 represented the body fat distribution, being a body shape index the most important variable in this factor. After adjustment by confounding factors, only the pattern 2 remained significantly associated with DM in women.

CONCLUSIONS

Only the anthropometric pattern of adiposity central was associated with DM in older women. Geriatr Gerontol Int 2018; 18: 584-591.

Early body composition, but not body mass, is associated with future accelerated decline in muscle quality

BACKGROUND

Muscle quality (MQ) or strength-to-mass ratio declines with aging, but the rate of MQ change with aging is highly heterogeneous across individuals. The identification of risk factors for accelerated MQ decline may offer clues to identity the underpinning physiological mechanisms and indicate targets for prevention and treatment. Using data from the Baltimore Longitudinal Study of Aging, we tested whether measures of body mass and body composition are associated with differential rates of changes in MQ with aging.

METHODS

Participants included 511 men and women, aged 50 years or older, followed for an average of 4 years (range: 1-8). MQ was operationalized as ratio between knee-extension isokinetic strength and CT-thigh muscle cross-sectional area. Predictors included body mass and body composition measures: weight (kg), body mass index (BMI, kg/m² ), dual-energy x-ray absorptiometry-measured total body fat mass (TFM, kg) and lean mass (TLM, kg), and body fatness (TFM/weight). Covariates were baseline age, sex, race, and body height.

RESULTS

Muscle quality showed a significant linear decline over the time of the follow up (average rate of decline 0.02 Nm/cm² per year, P < .001). Independent of covariates, neither baseline body weight (P = .756) nor BMI (P = .777) was predictive of longitudinal rate of decline in MQ. Instead, higher TFM and lower TLM at baseline predicted steeper longitudinal decline in MQ (P = .036 and P < .001, respectively). In particular, participants with both high TFM and low TLM at baseline experienced the most dramatic decline compared with those with low TFM and high TLM (about 3% per year vs. 0.5% per year, respectively). Participants in the higher tertile of baseline body fatness presented a significantly faster decline of MQ than the rest of the population (P = .021). Similar results were observed when body mass, TFM, and TLM were modeled as time-dependent predictors.

CONCLUSIONS

Body composition, but not weight nor BMI, is associated with future MQ decline, suggesting that preventive strategies aimed at maintaining good MQ with aging should specifically target body composition features.

Cognitive Decline, Body Mass Index, and Waist Circumference in Community-Dwelling Elderly Participants

OBJECTIVE

The aim of this study was to explore the association of body mass index (BMI), waist circumference (WC), and BMI and WC changes over time with cognitive decline in a nationally representative sample.

METHODS

A total of 5239 participants (≥65 years) were followed for 3 years as part of the National Health and Aging Trends Study. Cox proportional hazard regression was applied to model the risk of cognitive decline.

RESULTS

BMI, after adjusting for WC and main confounders, was associated with reduced risk of cognitive decline (hazard ratio [HR] 0.97 for each unit BMI increase, 0.95-0.99). After stratifying by gender and age, this effect remained significant among females and young elders ≤80 years. A BMI decrease and WC increase >10% over the study period were associated with increased risk of cognitive decline (HR 1.98, 1.16-3.38; HR 1.30, 1.04-1.62, respectively).

CONCLUSION

In the elderly individuals, lean mass, as measured by BMI adjusted for WC, was associated with reduced risk of cognitive decline. Loss of lean mass and gain of fat mass, as measured by WC adjusted for BMI, were associated with elevated risk of cognitive decline.

Obesity and physical frailty in older adults: a scoping review of lifestyle intervention trials

Many frail older adults are thin, weak, and undernourished; this component of frailty remains a critical concern in the geriatric field. However, there is also strong evidence that excessive adiposity contributes to frailty by reducing the ability of older adults to perform physical activities and increasing metabolic instability. Our scoping review explores the impact of being obese on physical frailty in older adults by summarizing the state of the science for both clinical markers of physical function and biomarkers for potential underlying causes of obesity-related decline. We used the 5-stage methodological framework of Arksey and O'Malley to conduct a scoping review of randomized trials of weight loss and/or exercise interventions for obesity (body mass index ≥ 30 kg/m(2)) in older adults (aged >60 years), examining the outcomes of inflammation, oxidative stress, and lipid accumulation in muscle, as well as direct measures of physical function. Our initial search yielded 212 articles; exclusion of cross-sectional and observational studies, cell culture and animal studies, disease-specific interventions, and articles published before 2001 led to a final result of 21 articles. Findings of these trials included the following major points. The literature consistently confirmed benefits of lifestyle interventions to physical function assessed at the clinical level. Generally speaking, weight loss alone produced a greater effect than exercise alone, and the best outcomes were achieved with a combination of weight loss and exercise, especially exercise programs that combined aerobic, resistance, and flexibility training. Weight loss interventions tended to reduce markers of inflammation and/or oxidative damage when more robust weight reduction was achieved and maintained over time, whereas exercise did not change markers of inflammation. However, participation in a chronic exercise program did reduce the oxidative stress induced by an acute bout of exercise. Weight loss interventions consistently reduced lipid accumulation in the muscle; however, in response to exercise, 3 studies showed an increase and 2 a decrease in muscle lipid infiltration. In summary, this scoping review identified strong clinical evidence that weight reduction and/or exercise interventions can improve physical function and biomarkers of physical dysfunction among overweight/obese older adults, supporting the suggestion that excessive adiposity contributes to physical frailty. However, the evidence also suggests a complexity of metabolic influences, both systemically and within muscle, which has not been elucidated to date. Considerable further study is needed to examine the mechanisms by which lifestyle interventions influence physical frailty before the net impact of such interventions can be fully understood.

Impaired mitochondrial fatty acid oxidation and insulin resistance in aging: novel protective role of glutathione

Aging is associated with impaired fasted oxidation of nonesterified fatty acids (NEFA) suggesting a mitochondrial defect. Aging is also associated with deficiency of glutathione (GSH), an important mitochondrial antioxidant, and with insulin resistance. This study tested whether GSH deficiency in aging contributes to impaired mitochondrial NEFA oxidation and insulin resistance, and whether GSH restoration reverses these defects. Three studies were conducted: (i) in 82-week-old C57BL/6 mice, the effect of naturally occurring GSH deficiency and its restoration on mitochondrial (13) C1 -palmitate oxidation and glucose metabolism was compared with 22-week-old C57BL/6 mice; (ii) in 20-week C57BL/6 mice, the effect of GSH depletion on mitochondrial oxidation of (13) C1 -palmitate and glucose metabolism was studied; (iii) the effect of GSH deficiency and its restoration on fasted NEFA oxidation and insulin resistance was studied in GSH-deficient elderly humans, and compared with GSH-replete young humans. Chronic GSH deficiency in old mice and elderly humans was associated with decreased fasted mitochondrial NEFA oxidation and insulin resistance, and these defects were reversed with GSH restoration. Acute depletion of GSH in young mice resulted in lower mitochondrial NEFA oxidation, but did not alter glucose metabolism. These data suggest that GSH is a novel regulator of mitochondrial NEFA oxidation and insulin resistance in aging. Chronic GSH deficiency promotes impaired NEFA oxidation and insulin resistance, and GSH restoration reverses these defects. Supplementing diets of elderly humans with cysteine and glycine to correct GSH deficiency could provide significant metabolic benefits.

The normal limits, subclinical significance, related metabolic derangements and distinct biological effects of body site-specific adiposity in relatively healthy population

Background

The accumulation of visceral adipose tissue that occurs with normal aging is associated with increased cardiovascular risks. However, the clinical significance, biological effects, and related cardiometabolic derangements of body-site specific adiposity in a relatively healthy population have not been well characterized.

Materials and Methods

In this cross-sectional study, we consecutively enrolled 608 asymptomatic subjects (mean age: 47.3 years, 27% female) from 2050 subjects undergoing an annual health survey in Taiwan. We measured pericardial (PCF) and thoracic peri-aortic (TAT) adipose tissue volumes by 16-slice multi-detector computed tomography (MDCT) (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA) and related these to clinical characteristics, body fat composition (Tanita 305 Corporation, Tokyo, Japan), coronary calcium score (CCS), serum insulin, high-sensitivity C-reactive protein (Hs-CRP) level and circulating leukocytes count. Metabolic risk was scored by Adult Treatment Panel III guidelines.

Results

TAT, PCF, and total body fat composition all increased with aging and higher metabolic scores (all p<0.05). Only TAT, however, was associated with higher circulating leukocyte counts (ß-coef.:0.24, p<0.05), serum insulin (ß-coef.:0.17, p<0.05) and high sensitivity C-reactive protein (ß-coef.:0.24, p<0.05). These relationships persisted after adjustment in multivariable models (all p<0.05). A TAT volume of 8.29 ml yielded the largest area under the receiver operating characteristic curve (AUROC: 0.79, 95%CI: 0.74–0.83) to identify metabolic syndrome. TAT but not PCF correlated with higher coronary calcium score after adjustment for clinical variables (all p<0.05).

Conclusion

In our study, we observe that age-related body-site specific accumulation of adipose tissue may have distinct biological effects. Compared to other adiposity measures, peri-aortic adiposity is more tightly associated with cardiometabolic risk profiles and subclinical atherosclerosis in a relatively healthy population.

Antiaging effect of dietary chitosan supplementation on glutathione-dependent antioxidant system in young and aged rats

Aging has been defined as the changes that occur in living organisms with the passage of time that lead to functional impairment and ultimately to death. Free radical-induced oxidative damage has long been thought to be the most important consequence of the aging process. In the present study, an attempt has been made to study the salubrious effects of dietary supplementation of chitosan on glutathione-dependent antioxidant defense system in young and aged rats. The dietary supplementation of chitosan significantly reduced the age-associated dyslipidemic abnormalities noted in the levels of total cholesterol, HDL-cholesterol, and LDL-cholesterol in plasma and heart tissue. Its administration significantly (P < 0.05) attenuated the oxidative stress in the heart tissue of aged rats through the counteraction of free radical formation by maintaining the enzymatic [glutathione peroxidase (GPx) and glutathione reductase (GR)] and non-enzymatic [reduced glutathione (GSH)] status at levels comparable to that of normal young rats. Our results conclude that dietary intake of chitosan restores the depleted myocardial antioxidant status and suggest that it could be an effective therapeutic agent in treatment of age-associated disorders where hypercholesterolemia and oxidative stress are the major causative factors.

Mitochondrial respiration in human viable platelets--methodology and influence of gender, age and storage

Studying whole cell preparations with intact mitochondria and respiratory complexes has a clear benefit compared to isolated or disrupted mitochondria due to the dynamic interplay between mitochondria and other cellular compartments. Platelet mitochondria have a potential to serve as a source of human viable mitochondria when studying mitochondrial physiology and pathogenic mechanisms, as well as for the diagnostics of mitochondrial diseases. The objective of the present study was to perform a detailed evaluation of platelet mitochondrial respiration using high-resolution respirometry. Further, we aimed to explore the limits of sample size and the impact of storage as well as to establish a wide range of reference data from different pediatric and adult cohorts. Our results indicate that platelet mitochondria are well suited for ex-vivo analysis with the need for minute sample amounts and excellent reproducibility and stability.

Age- and stroke-related skeletal muscle changes: a review for the geriatric clinician

Independently, aging and stroke each have a significant negative impact on skeletal muscle, but the potential cumulative effects of aging and stroke have not been explored. Optimal interventions for individuals post stroke may include those that specifically target skeletal muscle. Addressing changes in muscles may minimize activity limitations and enhance participation post stroke. This article reviews the impact of aging and stroke on muscle morphology and composition, including fiber atrophy, reductions in muscle cross-sectional area, changes in muscle fiber distributions, and increases in intramuscular fat. Relationships between changes in muscle structure, muscle function, and physical mobility are reviewed. Clinical recommendations that preserve and enhance skeletal muscle in the aging adult and individuals post stroke are discussed. Future research directions that include systematic comparison of the differences in skeletal muscle between younger and older adults who have sustained a stroke are suggested.

Chronic high-carbohydrate, high-fat feeding in rats induces reversible metabolic, cardiovascular, and liver changes

Age-related physiological changes develop at the same time as the increase in metabolic syndrome in humans after young adulthood. There is a paucity of data in models mimicking chronic diet-induced changes in human middle age and interventions to reverse these changes. This study measured the changes during chronic consumption of a high-carbohydrate (as cornstarch), low-fat (C) diet and a high-carbohydrate (as fructose and sucrose), high-fat (H) diet in rats for 32 wk. C diet feeding induced changes without metabolic syndrome, such as disproportionate increases in total body lean and fat mass, reduced bone mineral content, cardiovascular remodeling with increased systolic blood pressure, left ventricular and arterial stiffness, and increased plasma markers of liver injury. H diet feeding induced visceral adiposity with reduced lean mass, increased lipid infiltration in the skeletal muscle, impaired glucose and insulin tolerance, cardiovascular remodeling, hepatic steatosis, and increased infiltration of inflammatory cells in the heart and the liver. Chia seed supplementation for 24 wk attenuated most structural and functional modifications induced by age or H diet, including increased whole body lean mass and lipid redistribution from the abdominal area, and normalized the chronic low-grade inflammation induced by H diet feeding; these effects may be mediated by increased metabolism of anti-inflammatory n-3 fatty acids from chia seed. These results suggest that chronic H diet feeding for 32 wk mimics the diet-induced cardiovascular and metabolic changes in middle age and that chia seed may serve as an alternative dietary strategy in the management of these changes.

High fat diet induced insulin resistance and glucose intolerance are gender-specific in IGF-1R heterozygous mice

Interactions between genes and environment play a critical role in the pathogenesis of type 2 diabetes. Low birth weight, due to genetic and environmental variables affecting fetal growth, is associated with increased susceptibility to the development of type 2 diabetes and metabolic disorders in adulthood. Clinical studies have shown that polymorphisms in the Insulin-like growth factor 1 (IGF-1) gene or heterozygous mutations in IGF-1 and IGF-1 receptor (IGF-1R) genes, resulting in reduced IGF-1 action, are associated with low birth weight and post-natal growth. Mice lacking one of the IGF-1R alleles (Igf1r(+/-)) exhibit a 10% reduction in post-natal growth, and develop glucose intolerance (males) and insulin resistance (males and females) as they age. To investigate whether adverse environmental factors could accelerate the onset of the metabolic syndrome, we conducted a short duration intervention of high fat diet (HFD) feeding in male and female Igf1r(+/-) and wild-type (WT) control mice. The HFD resulted in insulin resistance, hyperglycemia, and impaired glucose tolerance in males of both genotypes whereas in females exacerbated diabetes was observed only in the Igf1r(+/-) genotype, thus suggesting a sexual dimorphism in the influence of obesity on the genetic predisposition to diabetes caused by reduced IGF-1 action.