The effect of pioglitazone and resistance training on body composition in older men and women undergoing hypocaloric weight loss

Diet and physical exercise in elderly people with obesity: The state of the art

Obesity is a disease that is assuming pandemic proportions in recent decades. With the advancement of medicine and increased access to care, average survival has increased, resulting in a larger number of elderly people. As a result, the amount of elderly people living with obesity is increasing, and the morbidity and impact of obesity on ageing implies severe limitations for these people. The link between obesity and ageing is not only epidemiological, but also strictly pathophysiological. Obesity accelerates the ageing process and ageing is characterised by pathophysiological mechanisms shared by obesity itself. Some examples of alterations shared by ageing and obesity are metabolic changes, sarcopenia and reduced functional capacity related to both loss of muscle strength and reduced cardiorespiratory fitness, as well as a general reduction in the perception of quality of life. The specific ability to antagonize these mechanisms through non-pharmacological treatment based on nutrition and exercise has always been one of the focal points of the international literature. Therefore, this review provides the state of the art on scientific knowledge regarding the main effects of an adequate nutritional plan and an individualised exercise prescription on the general health of elderly with obesity. In particular, this paper addresses the effect of nutrition and physical exercise on pathophysiological changes peculiar of ageing and obesity, providing also the scientific rational for nutritional and exercise prescription in the population.

The effects of myosteatosis on skeletal muscle function in older adults

Myosteatosis, or the infiltration of fatty deposits into skeletal muscle, occurs with advancing age and contributes to the health and functional decline of older adults. Myosteatosis and its inflammatory milieu play a larger role in adipose tissue dysfunction, muscle tissue dysfunction, and increased passive muscle stiffness. Combined with the age-related decline of sex hormones and development of anabolic resistance, myosteatosis also contributes to insulin resistance, impaired muscle mechanics, loss of force production from the muscle, and increased risk of chronic disease. Due to its highly inflammatory secretome and the downstream negative effects on muscle metabolism and mechanics, myosteatosis has become an area of interest for aging researchers and clinicians. Thus far, myosteatosis treatments have had limited success, as many lack the potency to completely rescue the metabolic and physical consequences of myosteatosis. Future research is encouraged for the development of reliable assessment methods for myosteatosis, as well as the continued exploration of pharmacological, nutritional, and exercise-related interventions that may lead to the success in attenuating myosteatosis and its clinical consequences within the aging population.

A review on associated factors and management measures for sarcopenia in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by hyperglycemia, insulin resistance, and insufficient insulin secretion. Sarcopenia, as a new complication of diabetes, is characterized by the loss of muscle mass and the progressive decline of muscle strength and function in T2DM patients, which has a serious impact on the physical and mental health of patients. Insulin resistance, mitochondrial dysfunction, and chronic inflammation are common mechanisms of diabetes and sarcopenia. Reasonable exercise training, nutrition supplement, and drug intervention may improve the quality of life of patients with diabetes combined with sarcopenia. This article reviews the relevant factors and management measures of sarcopenia in T2DM patients, in order to achieve early detection, diagnosis, and intervention.

The effect of thiazolidinediones on body fat redistribution in adults: A systematic review and meta-analysis of randomized controlled trials

Visceral adiposity is a strong predictor of cardiometabolic risk. Thiazolidinediones (TZDs) are associated with a shift in fat redistribution from visceral adipose tissue (VAT) to subcutaneous adipose tissue (SAT). We aimed to compare the effects of TZD and other interventions on fat remodeling in adults in randomized controlled trials. Among the 1331 retrieved studies, 39 trials with 1765 participants were included in the meta-analysis. The standardized mean difference in VAT change was not significantly different between TZD and comparators across the overall studies. Intriguingly, TZD treatment resulted in significant decreases in VAT compared with placebo and sulfonylureas (p < 0.05), although recombinant human growth hormone was superior to TZD regarding VAT reduction (p < 0.05). Data from 216 participants showed TZD leading to a greater reduction in liver fat percentage than comparators (p < 0.05). Compared with the controls, TZD significantly increased SAT, total body fat, weight, waist circumference, and body mass index (p < 0.05). However, TZD pronouncedly improved glucose control, insulin resistance, adiponectin, and lipid profile (p < 0.05). TZD provides a favorable effect on fat redistribution and benefits insulin sensitivity, suggesting a potentially valuable approach in cardiometabolic risk management.

The Current Landscape of Pharmacotherapies for Sarcopenia

Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.

Body Fat Distribution, Diabetes Mellitus, and Cardiovascular Disease: an Update

PURPOSE OF REVIEW

Specific measures of body fat distribution may have particular value in the development and treatment of cardiometabolic conditions, such as cardiovascular disease (CVD) and diabetes mellitus (DM). Here, we review the pathophysiology, epidemiology, and recent advances in the identification and management of body fat distribution as it relates to DM and CVD risk.

RECENT FINDINGS

Accumulation of visceral and ectopic fat is a major contributor to CVD and DM risk above and beyond the body mass index (BMI), yet implementation of fat distribution assessment into clinical practice remains a challenge. Newer imaging-based methods offer improved sensitivity and specificity for measuring specific fat depots. Lifestyle, pharmacological, and surgical interventions allow a multidisciplinary approach to reduce visceral and ectopic fat. A focus on implementation of body fat distribution measurements into clinical practice should be a priority over the next 5 to 10 years, and clinical assessment of fat distribution can be considered to refine risk evaluation and to develop improved and effective preventive and therapeutic strategies for high-risk obesity.

Current Nutritional and Pharmacological Approaches for Attenuating Sarcopenia

Sarcopenia is characterized by a gradual slowing of movement due to loss of muscle mass and quality, decreased power and strength, increased risk of injury from falls, and often weakness. This review will focus on recent research trends in nutritional and pharmacological approaches to controlling sarcopenia. Because nutritional studies in humans are fairly limited, this paper includes many results from nutritional studies in mammals. The combination of resistance training with supplements containing amino acids is the gold standard for preventing sarcopenia. Amino acid (HMB) supplementation alone has no significant effect on muscle strength or muscle mass in sarcopenia, but the combination of HMB and exercise (whole body vibration stimulation) is likely to be effective. Tea catechins, soy isoflavones, and ursolic acid are interesting candidates for reducing sarcopenia, but both more detailed basic research on this treatment and clinical studies in humans are needed. Vitamin D supplementation has been shown not to improve sarcopenia in elderly individuals who are not vitamin D-deficient. Myostatin inhibitory drugs have been tried in many neuromuscular diseases, but increases in muscle mass and strength are less likely to be expected. Validation of myostatin inhibitory antibodies in patients with sarcopenia has been positive, but excessive expectations are not warranted.

Resistance Training and Weight Loss in Older Adults: A Scoping Review

Resistance training (RT) is one of the most effective interventions available to older adults wishing to slow the progressive loss of muscle size and strength known to occur with age. Less is known about the ability of RT to resist the onset of an equally problematic condition related to increased age: obesity. The objective of this scoping review was to characterize current research associated with RT and weight loss in older adults, including protocols, feasibility, and gaps in current knowledge. We searched six databases using variations of the terms "resistance training," "weight loss," and "older adults" for experimental or quasi-experimental studies published in the year 2009 or later. Studies were included if they featured at least one treatment group with a mean age of > 65 years that engaged in an RT-only exercise protocol with no aerobic or high-intensity interval component. Of the 6102 references identified by the initial database search, 24 were retained for analysis. Older women and older adults with obesity or sarcopenic obesity were the most studied groups (n = 13), followed by healthy community-dwelling older adults (n = 11) and studies involving older adults and some aspect of either dietary control or pharmaceutical intervention (n = 8). Significant between-study heterogeneity was observed in the RT characteristics researchers thought optimal for improving body composition measures in older adults. Changes in body composition, rather than total body mass, were found to be the essential variables to consider when evaluating the effectiveness of an RT intervention aimed at reducing chronic disease in older adults. Weight loss alone appears to be an incomplete and problematic outcome measure for older adults, with changes in body composition (ratio of fat mass to lean mass) being the more appropriate variable to emphasize in this population. However, it is important to note that only one study, showing questionably reproducible findings, found a significant lean body mass gain. The lack of abundant high-quality evidence demonstrating combined RT and a healthy diet can lead to significant fat loss and lean body mass gain, coupled with high attrition rates observed in many of the studies reviewed, highlight the need for further rigorous research.

Repurposing Drugs for Diabetes Mellitus as Potential Pharmacological Treatments for Sarcopenia - A Narrative Review

Sarcopenia, the age-related loss of muscle strength and mass or quality, is a common condition with major adverse consequences. Although the pathophysiology is incompletely understood, there are common mechanisms between sarcopenia and the phenomenon of accelerated ageing seen in diabetes mellitus. Drugs currently used to treat type 2 diabetes mellitus may have mechanisms of action that are relevant to the prevention and treatment of sarcopenia, for those with type 2 diabetes and those without diabetes. This review summarises shared pathophysiology between sarcopenia and diabetes mellitus, including the effects of advanced glycation end products, mitochondrial dysfunction, chronic inflammation and changes to the insulin signalling pathway. Cellular and animal models have generated intriguing, albeit mixed, evidence that supports possible beneficial effects on skeletal muscle function for some classes of drugs used to treat diabetes, including metformin and SGLT2 inhibitors. Most human observational and intervention evidence for the effects of these drugs has been derived from populations with type 2 diabetes mellitus, and there is a need for intervention studies for older people with, and at risk of, sarcopenia to further investigate the balance of benefit and risk in these target populations. Not all diabetes treatments will be safe to use in those without diabetes because of variable side effects across classes. However, some agents [including glucagon-like peptide (GLP)-1 receptor agonists and SGLT2 inhibitors] have already demonstrated benefits in populations without diabetes, and it is these agents, along with metformin, that hold out the most promise for further investigation in sarcopenia.

A Randomized, Controlled Trial of Resistance Training Added to Caloric Restriction Plus Aerobic Exercise Training in Obese Heart Failure With Preserved Ejection Fraction

BACKGROUND

We have shown that combined caloric restriction (CR) and aerobic exercise training (AT) improve peak exercise O2 consumption (VO2peak), and quality-of-life in older patients with obese heart failure with preserved ejection fraction. However, ≈35% of weight lost during CR+AT was skeletal muscle mass. We examined whether addition of resistance training (RT) to CR+AT would reduce skeletal muscle loss and further improve outcomes.

METHODS

This study is a randomized, controlled, single-blind, 20-week trial of RT+CR+AT versus CR+AT in 88 patients with chronic heart failure with preserved ejection fraction and body mass index (BMI) ≥28 kg/m2. Outcomes at 20 weeks included the primary outcome (VO2peak); MRI and dual X-ray absorptiometry; leg muscle strength and quality (leg strength ÷ leg skeletal muscle area); and Kansas City Cardiomyopathy Questionnaire.

RESULTS

Seventy-seven participants completed the trial. RT+CR+AT and CR+AT produced nonsignificant differences in weight loss: mean (95% CI): -8 (-9, -7) versus -9 (-11, -8; P=0.21). RT+CR+AT and CR+AT had non-significantly differences in the reduction of body fat [-6.5 (-7.2, -5.8) versus -7.4 (-8.1, -6.7) kg] and skeletal muscle [-2.1 (-2.7, -1.5) versus -2.1 (-2.7, -1.4) kg] (P=0.20 and 0.23, respectively). RT+CR+AT produced significantly greater increases in leg muscle strength [4.9 (0.7, 9.0) versus -1.1 (-5.5, 3.2) Nm, P=0.05] and leg muscle quality [0.07 (0.03, 0.11) versus 0.02 (-0.02, 0.06) Nm/cm2, P=0.04]. Both RT+CR+AT and CR+AT produced significant improvements in VO2peak [108 (958, 157) versus 80 (30, 130) mL/min; P=0.001 and 0.002, respectively], and Kansas City Cardiomyopathy Questionnaire score [17 (12, 22) versus 23 (17, 28); P=0.001 for both], with no significant between-group differences. Both RT+CR+AT and CR+AT significantly reduced LV mass and arterial stiffness. There were no study-related serious adverse events.

CONCLUSIONS

In older obese heart failure with preserved ejection fraction patients, CR+AT produces large improvements in VO2peak and quality-of-life. Adding RT to CR+AT increased leg strength and muscle quality without attenuating skeletal muscle loss or further increasing VO2peak or quality-of-life.

REGISTRATION

URL: https://ClincalTrials.gov; Unique identifier: NCT02636439.

Can pioglitazone be used for optimization of nutrition in critical illness? A systematic review

BACKGROUND

Skeletal muscle wasting is a determinant of physical disability in survivors of critical illness. Intramuscular bioenergetic failure, altered substrate metabolim, and inflammation are likely underpinning mechanisms. We examined the effect of pioglitazone, a peroxisome proliferator-activated receptor γ agonist, on muscle-related outcomes in adults.

METHODS

We included randomized controlled trials in which pioglitazone was administered (no dose/dosage restrictions) and muscle-related outcomes were reported. We searched MEDLINE, CENTRAL, EMBASE, CINAHL, and trial registries. Risk of bias was assessed using RoB 2. Primary outcomes were physical function and symptoms, muscle mass and function, or body composition and muscular compositional change. Secondary outcomes included muscle insulin sensitivity, mitochondrial effects, and intramuscular inflammation.

RESULTS

Fourteen studies over 19 publications (n = 474 patients) were included. Lean body mass was unaffected in three studies (n = 126) and increased by 1.8-1.92 kg in two studies (P = 0.02 and 0.003, respectively; n = 48). Pioglitazone was associated with increased peripheral insulin sensitivity (+23%-72%, standardized mean difference of 0.97 from trial start point to end point [95% CI, 0.36-1.58; n = 213]). Treatment reduced intramuscular tumor necrosis factor-α (TNF-α) levels (-30%; P = 0.02; n = 29), with mixed effects on serum TNF-α and intramyocellular lipid concentrations. Treatment increased intramuscular markers of adenosine triphosphate (ATP) biosynthesis (ATP5A [+33%, P ≤ 0.05], ETFA [+60%, P ≤ 0.05], and CX6B1 [+ 33%, P = 0.01] [n = 24]), PGC1α and PGC1β messenger RNA expression (P < 0.05; n = 26), and AMPK phosphorylation (+38%, P < 0.05; n = 26). These data have low-quality evidence profiles owing to risk of bias.

CONCLUSIONS

Pioglitazone therapy increases skeletal muscle insulin sensitivity and can decrease intramuscular inflammation.

Intermuscular adipose tissue in metabolic disease

Intermuscular adipose tissue (IMAT) is a distinct adipose depot described in early reports as a 'fatty replacement' or 'muscle fat infiltration' that was linked to ageing and neuromuscular disease. Later studies quantifying IMAT with modern in vivo imaging methods (computed tomography and magnetic resonance imaging) revealed that IMAT is proportionately higher in men and women with type 2 diabetes mellitus and the metabolic syndrome than in people without these conditions and is associated with insulin resistance and poor physical function with ageing. In parallel, agricultural research has provided extensive insight into the role of IMAT and other muscle lipids in muscle (that is, meat) quality. In addition, studies using rodent models have shown that IMAT is a bona fide white adipose tissue depot capable of robust triglyceride storage and turnover. Insight into the importance of IMAT in human biology has been limited by the dearth of studies on its biological properties, that is, the quality of IMAT. However, in the past few years, investigations have begun to determine that IMAT has molecular and metabolic features that distinguish it from other adipose tissue depots. These studies will be critical to further decipher the role of IMAT in health and disease and to better understand its potential as a therapeutic target.

Metabolic changes in aging humans: current evidence and therapeutic strategies

Aging and metabolism are inextricably linked, and many age-related changes in body composition, including increased central adiposity and sarcopenia, have underpinnings in fundamental aging processes. These age-related changes are further exacerbated by a sedentary lifestyle and can be in part prevented by maintenance of activity with aging. Here we explore the age-related changes seen in individual metabolic tissues - adipose, muscle, and liver - as well as globally in older adults. We also discuss the available evidence for therapeutic interventions such as caloric restriction, resistance training, and senolytic and senomorphic drugs to maintain healthy metabolism with aging, focusing on data from human studies.

Hypoglycaemic therapy in frail older people with type 2 diabetes mellitus-a choice determined by metabolic phenotype

Frailty is a newly emerging complication of diabetes in older people and increasingly recognised in national and international clinical guidelines. However, frailty remains less clearly defined and frail older people with diabetes are rarely characterised. The general recommendation of clinical guidelines is to aim for a relaxed glycaemic control, mainly to avoid hypoglycaemia, in this often-vulnerable group of patients. With increasing age and development of frailty, body composition changes are characterised by an increase in visceral adipose tissue and a decrease in body muscle mass. Depending on the overall body weight, differential loss of muscle fibre types and body adipose/muscle tissue ratio, the presence of any associated frailty can be seen as a spectrum of metabolic phenotypes that vary in insulin resistance of which we have defined two specific phenotypes. The sarcopenic obese (SO) frail phenotype with increased visceral fat and increased insulin resistance on one side of spectrum and the anorexic malnourished (AM) frail phenotype with significant muscle loss and reduced insulin resistance on the other. In view of these varying metabolic phenotypes, the choice of hypoglycaemic therapy, glycaemic targets and overall goals of therapy are likely to be different. In the SO phenotype, weight-limiting hypoglycaemic agents, especially the new agents of GLP-1RA and SGLT-2 inhibitors, should be considered early on in therapy due to their benefits on weight reduction and ability to achieve tight glycaemic control where the focus will be on the reduction of cardiovascular risk. In the AM phenotype, weight-neutral agents or insulin therapy should be considered early on due to their benefits of limiting further weight loss and the possible anabolic effects of insulin. Here, the goals of therapy will be a combination of relaxed glycaemic control and avoidance of hypoglycaemia; and the focus will be on maintenance of a good quality of life. Future research is still required to develop novel hypoglycaemic agents with a positive effect on body composition in frailty and improvements in clinical outcomes.

PPAR-γ Gene Expression in Human Adipose Tissue Is Associated with Weight Loss After Sleeve Gastrectomy

BACKGROUND

The peroxisome proliferator-activated receptor (PPAR)-γ plays a key role in adipose tissue differentiation and fat metabolism. However, it is unclear which factors may regulate its expression and whether obese patients have changes in adipose tissue expression of PPAR-γor potential regulators such as miR-27. Thus, our aims were to analyze PPAR-γ and miR-27 expression in adipose tissue of obese patients, and to correlate their levels with clinical variables.

SUBJECTS AND METHODS

We included 43 morbidly obese subjects who underwent sleeve gastrectomy (31 of them completed 1-year follow-up) and 19 non-obese subjects. mRNA expression of PPAR-γ1 and PPAR-γ2, miR-27a, and miR-27b was measured by qPCR in visceral and subcutaneous adipose tissue. Clinical variables and serum adipokine and hormone levels were correlated with PPAR-γ and miR-27 expression. In addition, a systematic review of the literature regarding PPAR-γ expression in adipose tissue of obese patients was performed.

RESULTS

We found no differences in the expression of PPAR-γ and miR-27 in adipose tissue of obese patients vs. controls. The literature review revealed discrepant results regarding PPAR-γ expression in adipose tissue of obese patients. Of note, we described a significant negative correlation between pre-operative PPAR-γ1 expression in adipose tissue of obese patients and post-operative weight loss, potentially linked with insulin resistance markers.

CONCLUSION

PPAR-γ1 expression in adipose tissue is associated with weight loss after sleeve gastrectomy and may be used as a biomarker for response to surgery.

Anti-diabetic drugs and sarcopenia: emerging links, mechanistic insights, and clinical implications

Sarcopenia, characterized by loss of skeletal muscle mass, quality, and strength, has become a common hallmark of ageing and many chronic diseases. Diabetes mellitus patients have a higher prevalence of sarcopenia, which greatly aggravates the metabolic disturbance and compromises treatment response. Preclinical and clinical studies have shown differential impacts of anti-diabetic drugs on skeletal muscle mass, strength, and performance, highlighting the importance of rational therapeutic regimen from the perspective of sarcopenia risk. In this review, we provide an update on the regulation of muscle mass and quality by major anti-diabetic drugs, focusing primarily on emerging data from clinical studies. We also discuss the underlying mechanisms and clinical implications for optimal selection of anti-diabetic drugs to reduce the risk of sarcopenia. In view of the lifelong use of anti-diabetic drugs, we propose that a better understanding of the sarcopenia risk and interventional strategies is worthy of attention in future studies.

Quality Matters as Much as Quantity of Skeletal Muscle: Clinical Implications of Myosteatosis in Cardiometabolic Health

Although age-related changes in skeletal muscles are closely associated with decreases in muscle strength and functional decline, their associations with cardiometabolic diseases in the literature are inconsistent. Such inconsistency could be explained by the fact that muscle quality-which is closely associated with fatty infiltration of the muscle (i.e., myosteatosis)-is as important as muscle quantity in cardiometabolic health. However, muscle quality has been less explored compared with muscle mass. Moreover, the standard definition of myosteatosis and its assessment methods have not been established yet. Recently, some techniques using single axial computed tomography (CT) images have been introduced and utilized in many studies, as the mass and quality of abdominal muscles could be measured opportunistically on abdominal CT scans obtained during routine clinical care. Yet, the mechanisms by which myosteatosis affect metabolic and cardiovascular health remain largely unknown. In this review, we explore the recent advances in the assessment of myosteatosis and its changes associated with aging. We also review the recent literature on the clinical implication of myosteatosis by focusing on metabolic and cardiovascular diseases. Finally, we discuss the challenges and unanswered questions that need addressing to set myosteatosis as a therapeutic target for the prevention or treatment of cardiometabolic diseases.

The Impact of Glucose-Lowering Drugs on Sarcopenia in Type 2 Diabetes: Current Evidence and Underlying Mechanisms

The age-related decrease in skeletal muscle mass together with the loss of muscle power and function is defined sarcopenia. Mounting evidence suggests that the prevalence of sarcopenia is higher in patients with type 2 diabetes mellitus (T2DM), and different mechanisms may be responsible for this association such as impaired insulin sensitivity, chronic hyperglycemia, advanced glycosylation end products, subclinical inflammation, microvascular and macrovascular complications. Glucose-lowering drugs prescribed for patients with T2DM might impact on these mechanisms leading to harmful or beneficial effect on skeletal muscle. Importantly, beyond their glucose-lowering effects, glucose-lowering drugs may affect per se the equilibrium between protein anabolism and catabolism through several mechanisms involved in skeletal muscle physiology, contributing to sarcopenia. The aim of this narrative review is to provide an update on the effects of glucose-lowering drugs on sarcopenia in individuals with T2DM, focusing on the parameters used to define sarcopenia: muscle strength (evaluated by handgrip strength), muscle quantity/quality (evaluated by appendicular lean mass or skeletal muscle mass and their indexes), and physical performance (evaluated by gait speed or short physical performance battery). Furthermore, we also describe the plausible mechanisms by which glucose-lowering drugs may impact on sarcopenia.

Gender differences in the efficacy of pioglitazone treatment in nonalcoholic fatty liver disease patients with abnormal glucose metabolism

Background

Pioglitazone is a promising therapeutic method for nonalcoholic fatty liver disease (NAFLD) patients with or without type 2 diabetes. However, there is remarkable variability in treatment response. We analyzed our previous randomized controlled trial to examine the effects of gender and other factors on the efficacy of pioglitazone in treating Chinese nonalcoholic fatty liver disease (NAFLD) patients with abnormal glucose metabolism.

Methods

This is a post hoc analysis of a previous randomized, parallel controlled, open-label clinical trial (RCT) with an original purpose of evaluating the efficacy of berberine and pioglitazone on NAFLD. The total population (n = 185) was randomly divided into three groups: lifestyle intervention (LSI), LSI + pioglitazone (PGZ) 15 mg qd, and LSI + berberine (BBR) 0.5 g tid, respectively, for 16 weeks. The study used proton magnetic resonance spectroscopy (¹H-MRS) to assess liver fat content.

Results

As compared with LSI, PGZ + LSI treatment further decreased liver fat content in women (− 15.24% ± 14.54% vs. − 8.76% ± 13.49%, p = 0.025), but less decreased liver fat content in men (− 9.95% ± 15.18% vs. − 12.64% ± 17.78%, p = 0.046). There was a significant interaction between gender and efficacy of pioglitazone before and after adjustment for age, smoking, drinking, baseline BMI, BMI change, treatment adherence, baseline liver fat content, and glucose metabolism.

Conclusion

The study recommends pioglitazone plus lifestyle intervention for Chinese NAFLD female patients with abnormal glucose metabolism.

Trial registration

Role of Pioglitazone and Berberine in Treatment of Non-Alcoholic Fatty Liver Disease, NCT00633282. Registered on 3 March 2008, https://register.clinicaltrials.gov.

Myosteatosis in the Context of Skeletal Muscle Function Deficit: An Interdisciplinary Workshop at the National Institute on Aging

Skeletal muscle fat infiltration (known as myosteatosis) is an ectopic fat depot that increases with aging and is recognized to negatively correlate with muscle mass, strength, and mobility and disrupt metabolism (insulin resistance, diabetes). An interdisciplinary workshop convened by the National Institute on Aging Division of Geriatrics and Clinical Gerontology on September 2018, discussed myosteatosis in the context of skeletal muscle function deficit (SMFD). Its purpose was to gain a better understanding of the roles of myosteatosis in aging muscles and metabolic disease, particularly its potential determinants and clinical consequences, and ways of properly assessing it. Special attention was given to functional status and standardization of measures of body composition (including the value of D₃-creatine dilution method) and imaging approaches [including ways to better use dual-energy X-ray absorptiometry (DXA) through the shape and appearance modeling] to assess lean mass, sarcopenia, and myosteatosis. The workshop convened innovative new areas of scientific relevance to light such as the effect of circadian rhythms and clock disruption in skeletal muscle structure, function, metabolism, and potential contribution to increased myosteatosis. A muscle-bone interaction perspective compared mechanisms associated with myosteatosis and bone marrow adiposity. Potential preventive and therapeutic approaches highlighted ongoing work on physical activity, myostatin treatment, and calorie restriction. Myosteatosis' impact on cancer survivors raised new possibilities to identify its role and to engage in cross-disciplinary collaboration. A wide range of research opportunities and challenges in planning for the most appropriate study design, interpretation, and translation of findings into clinical practice were discussed and are presented here.

Myosteatosis in the Context of Skeletal Muscle Function Deficit: An Interdisciplinary Workshop at the National Institute on Aging

Skeletal muscle fat infiltration (known as myosteatosis) is an ectopic fat depot that increases with aging and is recognized to negatively correlate with muscle mass, strength, and mobility and disrupt metabolism (insulin resistance, diabetes). An interdisciplinary workshop convened by the National Institute on Aging Division of Geriatrics and Clinical Gerontology on September 2018, discussed myosteatosis in the context of skeletal muscle function deficit (SMFD). Its purpose was to gain a better understanding of the roles of myosteatosis in aging muscles and metabolic disease, particularly its potential determinants and clinical consequences, and ways of properly assessing it. Special attention was given to functional status and standardization of measures of body composition (including the value of D₃-creatine dilution method) and imaging approaches [including ways to better use dual-energy X-ray absorptiometry (DXA) through the shape and appearance modeling] to assess lean mass, sarcopenia, and myosteatosis. The workshop convened innovative new areas of scientific relevance to light such as the effect of circadian rhythms and clock disruption in skeletal muscle structure, function, metabolism, and potential contribution to increased myosteatosis. A muscle-bone interaction perspective compared mechanisms associated with myosteatosis and bone marrow adiposity. Potential preventive and therapeutic approaches highlighted ongoing work on physical activity, myostatin treatment, and calorie restriction. Myosteatosis’ impact on cancer survivors raised new possibilities to identify its role and to engage in cross-disciplinary collaboration. A wide range of research opportunities and challenges in planning for the most appropriate study design, interpretation, and translation of findings into clinical practice were discussed and are presented here.

Emerging molecular mediators and targets for age-related skeletal muscle atrophy

The age-associated decline in muscle mass has become synonymous with physical frailty among the elderly due to its major contribution in reduced muscle function. Alterations in protein and redox homeostasis along with chronic inflammation, denervation, and hormonal dysregulation are all hallmarks of muscle wasting and lead to clinical sarcopenia in older adults. Reduction in skeletal muscle mass has been observed and reported in the scientific literature for nearly 2 centuries; however, identification and careful examination of molecular mediators of age-related muscle atrophy have only been possible for roughly 3 decades. Here we review molecular targets of recent interest in age-related muscle atrophy and briefly discuss emerging small molecule therapeutic treatments for muscle wasting in sarcopenic susceptible populations.

The Impact of Antidiabetic Agents on Sarcopenia in Type 2 Diabetes: A Literature Review

Sarcopenia is a geriatric syndrome characterized by decline of skeletal muscle mass and function. Contributing factors include nutritional, genetic, inflammatory, and endocrinal factors. The reported prevalence of sarcopenia in type 2 diabetes mellitus is high, especially in patients with poor glycemic control. Additionally, antidiabetic agents may alter the balance between protein synthesis and degradation through various mechanisms of skeletal muscle mass regulation. This study reviewed the literature on the pathogenesis of sarcopenia in diabetes mellitus and the current understanding of whether antidiabetic agents contribute positively or negatively to sarcopenia and muscle wasting.

Prevention and Treatment of Sarcopenic Obesity in Women

Sarcopenic obesity (SO) is referred to as the combination of obesity with low skeletal muscle mass and function. However, its definition and diagnosis is debated. SO represents a sizable risk factor for the development of disability, possibly with a worse prognosis in women. The present narrative review summarizes the current evidence on pharmacological, nutrition and exercise strategies on the prevention and/or treatment of SO in middle-aged and older-aged women. A literature search was carried out in Medline and Google Scholar between 29th January and 14th March 2019. Only controlled intervention studies on mid-age and older women whose focus was on the prevention and/or treatment of sarcopenia associated with obesity were included. Resistance training (RT) appears effective in the prevention of all components of SO in women, resulting in significant improvements in muscular mass, strength, and functional capacity plus loss of fat mass, especially when coupled with hypocaloric diets containing at least 0.8 g/kg body weight protein. Correction of vitamin D deficit has a favorable effect on muscle mass. Treatment of SO already established is yet unsatisfactory, although intense and prolonged RT, diets with higher (1.2 g/kg body weight) protein content, and soy isoflavones all look promising. However, further confirmatory research and trials combining different approaches are required.

Treatment of obesity in older persons-A systematic review

The study aims to systematically review the available evidence regarding weight loss interventions (lifestyle, surgical, and pharmacological) for obesity in adults aged over 60 years. A search of prospective, randomized studies took place in January 2018, on Medline (Web of Science) and PubMed databases. Search terms included the following: elderly, obese, hypocaloric, pharmacotherapy, and bariatric surgery. Abstracts were screened for eligibility. A total of 256 publications regarding lifestyle interventions were identified; of these, 69 studies were eligible. As no eligible studies were identified for pharmacotherapy or bariatric surgery, the search was broadened to include non- randomized studies. Four pharmacotherapy and 66 surgery studies were included. Lifestyle intervention had similar weight loss efficacy in older compared with younger people, with positive effects on a number of relevant outcomes, including physical function and cardiovascular parameters. There was little data regarding obesity pharmacotherapy in older persons. The available data for bariatric surgery indicate comparable weight loss and resolution of type 2 diabetes, with similar or slightly higher complication rates in older compared with younger people. Older age alone should not be considered a contraindication to intensive lifestyle or surgical intervention for obesity. There are insufficient data to guide clinical decisions regarding obesity pharmacotherapy in older people.

Diabetes pharmacotherapy and effects on the musculoskeletal system

Persons with type 1 or type 2 diabetes have a significantly higher fracture risk than age-matched persons without diabetes, attributed to disease-specific deficits in the microarchitecture and material properties of bone tissue. Therefore, independent effects of diabetes drugs on skeletal integrity are vitally important. Studies of incretin-based therapies have shown divergent effects of different agents on fracture risk, including detrimental, beneficial, and neutral effects. The sulfonylurea class of drugs, owing to its hypoglycemic potential, is thought to amplify the risk of fall-related fractures, particularly in the elderly. Other agents such as the biguanides may, in fact, be osteo-anabolic. In contrast, despite similarly expected anabolic properties of insulin, data suggests that insulin pharmacotherapy itself, particularly in type 2 diabetes, may be a risk factor for fracture, negatively associated with determinants of bone quality and bone strength. Finally, sodium-dependent glucose co-transporter 2 inhibitors have been associated with an increased risk of atypical fractures in select populations, and possibly with an increase in lower extremity amputation with specific SGLT2I drugs. The role of skeletal muscle, as a potential mediator and determinant of bone quality, is also a relevant area of exploration. Currently, data regarding the impact of glucose lowering medications on diabetes-related muscle atrophy is more limited, although preclinical studies suggest that various hypoglycemic agents may have either aggravating (sulfonylureas, glinides) or repairing (thiazolidinediones, biguanides, incretins) effects on skeletal muscle atrophy, thereby influencing bone quality. Hence, the therapeutic efficacy of each hypoglycemic agent must also be evaluated in light of its impact, alone or in combination, on musculoskeletal health, when determining an individualized treatment approach. Moreover, the effect of newer medications (potentially seeking expanded clinical indication into the pediatric age range) on the growing skeleton is largely unknown. Herein, we review the available literature regarding effects of diabetes pharmacotherapy, by drug class and/or by clinical indication, on the musculoskeletal health of persons with diabetes.

Early life adversity blunts responses to pioglitazone in depressed, overweight adults

PURPOSE

Early life adversity is associated with both metabolic impairment and depression in adulthood, as well as with poorer responses to antidepressant medications. It is not yet known whether individual differences in sensitivity to antidiabetic medications could also be related to early life adversity. We examined whether a history of early life adversity affected the observed changes in metabolic function and depressive symptoms in a randomized trial of pioglitazone for augmentation of standard treatments for depression.

PURPOSE

Early life adversity is associated with both metabolic impairment and depression in adulthood, as well as with poorer responses to antidepressant medications. It is not yet known whether individual differences in sensitivity to antidiabetic medications could also be related to early life adversity. We examined whether a history of early life adversity affected the observed changes in metabolic function and depressive symptoms in a randomized trial of pioglitazone for augmentation of standard treatments for depression.

FINDINGS

We found that early life adversity significantly impaired the metabolic response to pioglitazone. Effects on depressive symptoms did not reach significance, but nonetheless suggested that pioglitazone could mitigate the depressant effects of childhood adversity, only among those insulin resistant at baseline.

CONCLUSIONS

We conclude that a history of early life adversity may impair the body's ability to respond to insulin sensitizing pharmacotherapy, and furthermore that its contribution to resistant depression may function in part via the generation of an insulin resistant phenotype.

Legacy effects of short-term intentional weight loss on total body and thigh composition in overweight and obese older adults

Objective:

Weight regain following intentional weight loss may negatively impact body composition, accelerating fat regain and increasing risk of physical disability. The purpose of this study was to compare long-term changes in whole body and thigh composition in obese older adults who intentionally lost and then partially regained weight to obese older adults who remained weight stable.

Subjects/Methods:

This pilot study analyzed total body (dual-energy X-ray absorptiometry (DXA)) and thigh (computed tomography (CT)) composition data collected from 24 older (65–79 years) adults 18 months after completion of a 5-month randomized trial that compared resistance training alone (RT) with RT plus caloric restriction (RT+CR).

Results:

Mean loss of body mass in the RT+CR group (n=13) was 7.1±2.4 kg during the 5-month intervention (74% fat mass; 26% lean mass; all P<0.01), whereas RT (n=11) remained weight stable (+0.3±1.8 kg; P=0.64). Differential group effects were observed for all DXA and CT body composition measures at 5 months (all P⩽0.01); however, by 23 months, group differences persisted only for total body (RT+CR: 81.6±10.0 kg vs RT: 88.5±14.9 kg; P=0.03) and lean (RT+CR: 50.8±9.3 kg vs RT: 54.4±12.0 kg; P<0.01) mass. All RT+CR participants regained weight from 5 to 23 months (mean gain=+4.8±2.6 kg; P<0.01). Total fat mass and all thigh fat volumes increased, whereas thigh muscle volume decreased, during the postintervention follow-up in RT+CR (all P⩽0.01). In the RT group, body mass did not change from 5 to 23 months (−0.2±0.9 kg; P=0.87). Decreased total thigh volume, driven by the loss of thigh muscle volume, were the only postintervention body composition changes observed in the RT group (both P<0.04).

Conclusions:

Short-term body composition benefits of an RT+CR intervention may be lost within 18 months after completion of the intervention.

Novel investigational drugs mimicking exercise for the treatment of cachexia

INTRODUCTION

Cachexia is a syndrome characterized by body weight loss, muscle wasting and metabolic abnormalities, that frequently complicates the management of people affected by chronic diseases. No effective therapy is actually available, although several drugs are under clinical evaluation. Altered energy metabolism markedly contributes to the pathogenesis of cachexia; it can be improved by exercise, which is able to both induce anabolism and inhibit catabolism.

AREAS COVERED

This review focuses on exercise mimetics and their potential inclusion in combined protocols to treat cachexia. The authors pay with particular reference to the cancer-associated cachexia.

EXPERT OPINION

Even though exercise improves muscle phenotype, most patients retain sedentary habits which are quite difficult to disrupt. Moreover, they frequently present with chronic fatigue and comorbidities that reduce exercise tolerance. For these reasons, drugs mimicking exercise could be beneficial to those who are unable to comply with the practice of physical activity. Since some exercise mimetics may exert serious side effects, further investigations should focus on treatments which maintain their effectiveness on muscle phenotype while remaining tolerable at the same time.

Exploration of the protein requirement during weight loss in obese older adults

RATIONALE

Currently there is no consensus on protein requirements for obese older adults during weight loss. Here we explore the potential use of a new method for assessment of protein requirements based on changes in appendicular muscle mass during weight loss.

METHODS

60 obese older adults were subjected to 13 wk weight loss program, including hypocaloric diet and resistance training. Assessment of appendicular muscle mass was performed by DXA at baseline and after 13 wk challenge period, and the difference calculated as muscle mass change. Protein intake (g/kg body weight and g/kg fat free mass (FFM)) at 13wks was used as marker of protein intake during 13 wk period. 30 subjects received 10 times weekly 20 g protein supplement throughout the 13 week hypocaloric phase which is included in the calculation of total protein intake. Receiver operating characteristic (ROC) curve analysis was used to explore the optimal cutoff point for protein intake (g/kg) versus increase in appendicular muscle mass of more than 250 g over 13 wks (y/n). Subsequently, logistic regression analysis was performed for protein intake cutoff and muscle mass accretion, adjusted for sex, age, baseline BMI, and training compliance.

RESULTS

ROC curve analysis provided a protein intake level per day of 1.2 g/kg bw and 1.9 g/kg FFM as cutoff point. Presence of muscle mass accretion during 13 wk challenge period was significantly higher with protein intake higher than 1.2 g/kg bw (OR 5.4, 95%CI 1.4-20.6, p = 0.013) or higher than 1.9 g/kg FFM (OR 8.1, 95%CI 2.1-31.9, p = 0.003). Subjects with a protein intake higher than 1.2 g/kg had significantly more often muscle mass accretion, compared to subjects with less protein intake (10/14 (72%) vs 15/46 (33%), p = 0.010). For 1.9 g/kg FFM this was 70% vs 28% (p = 0.002).

CONCLUSION

This exploratory study provided a level of at least 1.2 g/kg body weight or 1.9 g/kg fat free mass as optimal daily protein intake for obese older adults under these challenged conditions of weight loss, based on muscle mass accretion during the challenge.

TRIAL REGISTRATION

Dutch Trial Register under number NTR2751.

Treatment of body composition changes in obese and overweight older adults: insight into the phenotype of sarcopenic obesity

In recent years, mounting interest has been directed to sarcopenic obesity (SO), given the parallel increase of life expectancy and prevalence of obesity in Western countries. The phenotype of SO is characterized by the coexistence of excess fat mass and decreased muscle mass, leading to the impairment of physical performance. The aim of the present review was to summarize the impact of different treatment strategies contrasting body composition changes in older obese and overweight subjects, providing insight into the SO phenotype. Revision questions were formulated; relevant articles were identified from Pubmed through a systematic search strategy: definition of the search terms (sarcopenic obesity, diet, nutritional supplements, physical activity, exercise, pharmacological treatment); limits: papers published in the last 10 years; humans; age ≥ 60 years old; body mass index >25 kg/m(2); language: English. Studies dealing with sarcopenia associated to cancer cachexia or neurological diseases, any malignant disease, inflammatory or autoimmune diseases, corticosteroids for systemic use, bedridden subjects, and syndromic obesity were excluded. 14 articles were identified for inclusion in the present systematic review, and were grouped basing on the type of the main intervention: data assessing body composition changes after combined lifestyle interventions, exercise/physical activity, dietary interventions, and pharmacological treatment. Most of the studies were randomized, controlled. Sample size ranged from 12 to 439 subjects, and study duration varied from 6 weeks to 12 months. Weight loss based on diet combined with exercise seems to be the best strategy to adopt for treatment of phenotypic aspects of SO, improving metabolic consequences related to excess fat, preserving lean mass, and allowing functional recovery.

Effect of an 18-month physical activity and weight loss intervention on body composition in overweight and obese older adults

OBJECTIVE

Our primary objective was to determine the long-term effects of physical activity (PA) and weight loss (WL) on body composition in overweight/obese older adults. Secondarily, the association between change in body mass and composition on change in several cardiometabolic risk factors and mobility was evaluated.

DESIGN AND METHODS

288 older (X ± SD: 67.0 ± 4.8 years), overweight/obese (BMI 32.8 ± 3.8 kg/m² ) men and women participated in this 18-month randomized, controlled trial. Treatment groups included PA + WL (n = 98), PA-only (n = 97), and a successful aging (SA) health education control (n = 93). DXA-acquired body composition measures (total body fat and lean mass), conventional biomarkers of cardiometabolic risk, and 400-m walk time were obtained at baseline and 18 months.

RESULTS

Fat mass was significantly reduced from (X ± SE) 36.5 ± 8.9 kg to 31.7 ± 9.0 kg in the PA + WL group (p < 0.01), but remained unchanged from baseline in the PA-only (-0.8 ± 3.8 kg) and SA (-0.0 ± 3.9 kg) group. Lean mass losses were three times greater in the PA + WL groups compared to PA-only or SA groups (-2.5 ± 2.8 kg vs. -0.7 ± 2.2 kg or -0.8 ± 2.4 kg, respectively; p < 0.01); yet due to a larger decrease in fat mass, percent lean mass was significantly increased over baseline in the PA + WL groups (2.1% ± 2.6%; p < 0.01). Fat mass loss was primarily responsible for WL-associated improvements in cardiometabolic risk factors, while reduction in body weight, regardless of compartment, was significantly associated with improved mobility.

CONCLUSION

This 18-month PA + WL program resulted in a significant reduction in percent body fat with a concomitant increase in percent body lean mass. Shifts in body weight and composition were associated with favorable changes in clinical parameters of cardiometabolic risk and mobility. Moderate PA without WL had no effect on body composition.

Sex-stratified genome-wide association studies including 270,000 individuals show sexual dimorphism in genetic loci for anthropometric traits

Given the anthropometric differences between men and women and previous evidence of sex-difference in genetic effects, we conducted a genome-wide search for sexually dimorphic associations with height, weight, body mass index, waist circumference, hip circumference, and waist-to-hip-ratio (133,723 individuals) and took forward 348 SNPs into follow-up (additional 137,052 individuals) in a total of 94 studies. Seven loci displayed significant sex-difference (FDR<5%), including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were genome-wide significant in women (P<5×10(-8)), but not in men. Sex-differences were apparent only for waist phenotypes, not for height, weight, BMI, or hip circumference. Moreover, we found no evidence for genetic effects with opposite directions in men versus women. The PPARG locus is of specific interest due to its role in diabetes genetics and therapy. Our results demonstrate the value of sex-specific GWAS to unravel the sexually dimorphic genetic underpinning of complex traits.

Resistance training and pioglitazone lead to improvements in muscle power during voluntary weight loss in older adults

BACKGROUND

The prevalence of obesity in older adults is increasing but concerns exist about the effect of weight loss on muscle function. Demonstrating that muscle strength and power are not adversely affected during "intentional" weight loss in older adults is important given the wide-ranging negative health effects of excess adiposity.

METHODS

Participants (N = 88; age = 70.6 ± 3.6 years; body mass index = 32.8 ± 4.5 kg/m(2)) were randomly assigned to one of four intervention groups: pioglitazone or placebo and resistance training (RT) or no RT, while undergoing intentional weight loss via a hypocaloric diet. Outcomes were leg press power and isometric knee extensor strength. Analysis of covariance, controlling for baseline values, compared follow-up means of power and strength according to randomized groups.

RESULTS

Participants lost an average of 6.6% of initial body mass, and significant declines were observed in fat mass, lean body mass, and appendicular lean body mass. Compared with women not randomized to RT, women randomized to RT had significant improvements in leg press power (p < .001) but not in knee extensor strength (p = 0.12). No significant differences between groups in change in power or strength from baseline were detected in men (both p > .25). A significant pioglitazone-by-RT interaction for leg press power was detected in women (p = .006) but not in men (p = .88).

CONCLUSIONS

In older overweight and obese adults, a hypocaloric weight loss intervention led to significant declines in lean body mass and appendicular lean body mass. However, in women assigned to RT, leg power significantly improved following the intervention, and muscle strength or power was not adversely effected in the other groups. Pioglitazone potentiated the effect of RT on muscle power in women but not in men; mechanisms underlying this sex effect remain to be determined.

Fat mass loss predicts gain in physical function with intentional weight loss in older adults

BACKGROUND

Clinical recommendation of weight loss (WL) in older adults remains controversial, partially due to concerns regarding lean mass loss and potential loss of physical function. The purpose of this study is to determine the independent associations between changes in fat and lean mass and changes in physical function in older, overweight, and obese adults undergoing intentional WL.

METHODS

Data from three randomized-controlled trials of intentional WL in older adults with similar functional outcomes (short physical performance battery and Pepper assessment tool for disability) were combined. Analyses of covariance models were used to investigate relationships between changes in weight, fat, and lean mass (acquired using dual-energy x-ray absorptiometry) and changes in physical function.

RESULTS

Overall loss of body weight was -7.8 ± 6.1 kg (-5.6 ± 4.1 kg and -2.7 ± 2.4 kg of fat and lean mass, respectively). In all studies combined, after adjustment for age, sex, and height, overall WL was associated with significant improvements in self-reported mobility disability (p < .01) and walking speed (p < .01). Models including change in both fat and lean mass as independent variables found only the change in fat mass to significantly predict change in mobility disability (β[fat] = 0.04; p < .01) and walking speed (β[fat] = -0.01; p < .01).

CONCLUSIONS

Results from this study demonstrate that loss of body weight, following intentional WL, is associated with significant improvement in self-reported mobility disability and walking speed in overweight and obese older adults. Importantly, fat mass loss was found to be a more significant predictor of change in physical function than lean mass loss.