β-Hydroxy-β-methylbutyrate supplementation reduces tumor growth and tumor cell proliferation ex vivo and prevents cachexia in Walker 256 tumor-bearing rats by modifying nuclear factor-κB expression

Effects of parenteral nutrition supplemented with beta-hydroxy-beta-methylbutyrate on gut-associated lymphoid tissue and morphology in mice

BACKGROUND

Parenteral nutrition (PN) without enteral nutrition (EN) leads to marked atrophy of gut-associated lymphoid tissue (GALT), causing mucosal defense failure in both the gut and the extraintestinal mucosal system. We evaluated the effects of beta-hydroxy-beta-methylbutyrate (HMB) on GALT and gut morphology in PN-fed mice.

METHODS

Experiment 1: male Institute of Cancer Research mice were assigned to the Chow (n = 12), Control (standard PN: n = 10), or H600 and H2000 (PN containing 600 mg/kg or H2000 mg/kg body weight of Ca-HMB: n = 12 and 10, respectively) groups. After 5 days of dietary manipulation, all mice were killed and the whole small intestine was harvested. GALT lymphocyte cell numbers and phenotypes of Peyer patch (PP), intraepithelial space, and lamina propria lymphocytes were evaluated. Experiment 2: 47 mice (Chow: n = 12; Control: n = 14; H600: n = 11; and H2000: n = 10) were fed for 5 days as in experiment 1. Proliferation and apoptosis of gut immune cells and mucosa, and protein expressions (mammalian target of rapamycin [mTOR], caspase-3, and Bcl2) were evaluated in the small intestine.

RESULTS

Compared with the Controls, the Chow and HMB groups showed significantly higher PP cell numbers, prevented gut mucosal atrophy, inhibited apoptosis of gut cells, and increased their proliferation in association with increased mTOR activity and Bcl2 expression.

CONCLUSION

HMB-supplemented PN is a potentially novel method of preserving GALT mass and gut morphology in the absence of EN.

Effects of β-hydroxy β-methylbutyrate (HMB) supplementation on muscle mass, function, and other outcomes in patients with cancer: a systematic review

Low muscle mass is prevalent among patients with cancer and a predictor of adverse clinical outcomes. To counteract muscle loss, β-hydroxy β-methylbutyrate (HMB) supplementation has been proposed as a potential therapy for older adults and various diseases states. This systematic review aimed to investigate the effects and safety of HMB supplementation in relation to muscle mass and function and other clinical outcomes in patients with cancer. A systematic search of MEDLINE, CINAHL, Embase, Cochrane Central Register of Controlled Trials, Scopus, ProQuest, and grey literature for reports published from inception to December 2021 was conducted. Included studies provided supplements containing any dose of HMB to adult patients with active cancer. A synthesis without meta-analysis was conducted using a vote-counting approach based solely on the direction of the effect (i.e. regardless of statistical significance). Risk of bias was assessed for each outcome domain, and evidence from higher-quality studies (i.e. those with either low or moderate risk of bias) was examined. Safety was evaluated using both lower-quality and higher-quality studies. Fifteen studies were included, in which six were randomized controlled trials in patients with various cancer types and treatments. Studies prescribed HMB combined with amino acids (73.3%), HMB in oral nutritional supplements (20.0%), or both supplement types (6.7%); Ca-HMB doses of 3.0 g/day were provided in 80.0% of the studies. Four studies had high risk of bias across all outcome domains. Considering the higher-quality studies, evidence of a beneficial effect of HMB supplementation was found in four of four studies for muscle mass, two of two for muscle function, three of three for hospitalization, and five of seven for survival. In contrast, no beneficial effects of HMB on quality of life or body weight was found in two of four and three of five studies, respectively. A limited number of higher-quality studies evaluating the impact of HMB on cancer therapy-related toxicity, inflammation, and tumour response were observed. No serious adverse effects directly related to the nutrition intervention were reported. Although limited, current evidence suggests that HMB supplementation has a beneficial effect on muscle mass and function in patients with cancer. Well-designed trials are needed to further explore the clinical benefit of HMB supplementation in this patient population.

β-Hydroxy-β-Methylbutyrate Supplementation Promotes Antitumor Immunity in an Obesity Responsive Mouse Model of Pancreatic Ductal Adenocarcinoma

Simple Summary

Pancreatic cancer (PDAC) is a deadly disease, exacerbated by obesity, which lacks effective therapeutic interventions. Most PDAC has a limited response to immune- and chemotherapy. Treating PDAC is made additionally challenging by the rapid emergence of muscle wasting and cachexia, which predict poor response to several therapies. We have found that dietary supplementation with β-hydroxy-β-methylbutyrate promotes immunosurveillance in PDAC tumors and protects muscle. This dietary supplement has the potential to be an important adjuvant in PDAC therapy, opening the doors to immunotherapy response.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths in the United States, and effective therapies for PDAC are currently lacking. Moreover, PDAC is promoted and exacerbated by obesity, while cachexia and sarcopenia are exceptionally common comorbidities that predict both poor survival and treatment response. Managing PDAC with immunotherapies has thus far proven ineffective, partly due to the metabolically hostile tumor microenvironment. β-hydroxy-β-methylbutyrate (HMB), a metabolite of leucine commonly used as a dietary supplement to boost muscle growth and immune function, may be an attractive candidate to augment PDAC therapy. We therefore sought to test the hypothesis that HMB would enhance antitumor immunity while protecting mouse muscle mass. Control and diet-induced obese C57BL/6 male mice bearing subcutaneously injected Panc02 tumors were supplemented with 1% HMB and treated with or without 50 mg/kg gemcitabine (n = 15/group). HMB was associated with reduced muscle inflammation and increased muscle fiber size. HMB also reduced tumor growth and promoted antitumor immunity in obese, but not lean, mice, independent of the gemcitabine treatment. Separately, in lean tumor-bearing mice, HMB supplementation promoted an anti-PD1 immunotherapy response (n = 15/group). Digital cytometry implicated the decreased abundance of M2-like macrophages in PDAC tumors, an effect that was enhanced by anti-PD1 immunotherapy. We confirmed that HMB augments M1-like macrophage (antitumor) polarization. These preclinical findings suggest that HMB has muscle-sparing and antitumor activities against PDAC in the context of obesity, and that it may sensitize otherwise nonresponsive PDAC to immunotherapy.

Nutritional Interventions in Cancer Cachexia: Evidence and Perspectives From Experimental Models

Cancer cachexia is a complex metabolic syndrome characterized by involuntary skeletal muscle loss and is associated with poor clinical outcome, decreased survival and negatively influences cancer therapy. No curative treatments are available for cancer cachexia, but nutritional intervention is recommended as a cornerstone of multimodal therapy. Optimal nutritional care is pivotal in the treatment of cancer cachexia, and the effects of nutrients may extend beyond provision of adequate energy uptake, targeting different mechanisms or metabolic pathways that are affected or deregulated by cachexia. The evidence to support this notion derived from nutritional intervention studies in experimental models of cancer cachexia is systematically discussed in this review. Moreover, experimental variables and readout parameters to determine skeletal muscle wasting and cachexia are methodologically evaluated to allow critical comparison of similar studies. Single- and multinutrient intervention studies including qualitative modulation of dietary protein, dietary fat, and supplementation with specific nutrients, such as carnitine and creatine, were reviewed for their efficacy to counteract muscle mass loss and its underlying mechanisms in experimental cancer cachexia. Numerous studies showed favorable effects on impaired protein turnover and related metabolic abnormalities of nutritional supplementation in parallel with a beneficial impact on cancer-induced muscle wasting. The combination of high quality nutrients in a multitargeted, multinutrient approach appears specifically promising, preferentially as a multimodal intervention, although more studies investigating the optimal quantity and combination of nutrients are needed. During the review process, a wide variation in timing, duration, dosing, and route of supplementation, as well as a wide variation in animal models were observed. Better standardization in dietary design, and the development of experimental models that better recapitulate the etiology of human cachexia, will further facilitate successful translation of experimentally-based multinutrient, multimodal interventions into clinical practice.

Nutraceutical targeting of TLR4 signaling has potential for prevention of cancer cachexia

The mechanisms underlying cancer cachexia - the proximate cause of at least 20% of cancer-related deaths - have until recently remained rather obscure. New research, however, clarifies that cancers evoking cachexia release microvesicles rich in heat shock proteins 70 and 90, and that these extracellular heat shock proteins induce cachexia by serving as agonists for toll-like receptor 4 (TLR4) in skeletal muscle, macrophages, and adipocytes. Hence, safe nutraceutical measures which can down-regulate TLR4 signaling can be expected to aid prevention and control of cancer cachexia. There is reason to suspect that phycocyanobilin, ferulic acid, glycine, long-chain omega-3s, green tea catechins, β-hydroxy-β-methylbutyrate, carnitine, and high-dose biotin may have some utility in this regard.

Pancreatic Cancer Cachexia: The Role of Nutritional Interventions

Pancreatic cancer is a cancer with one of the highest mortality rates and many pancreatic cancer patients present with cachexia at diagnosis. The definition of cancer cachexia is not consistently applied in the clinic or across studies. In general, it is “defined as a multifactorial syndrome characterised by an ongoing loss of skeletal muscle mass with or without loss of fat mass that cannot be fully reversed by conventional nutritional support and leads to progressive functional impairment.” Many regard cancer cachexia as being resistant to dietary interventions. Cachexia is associated with a negative impact on survival and quality of life. In this article, we outline some of the mechanisms of pancreatic cancer cachexia and discuss nutritional interventions to support the management of pancreatic cancer cachexia. Cachexia is driven by a combination of reduced appetite leading to reduced calorie intake, increased metabolism, and systemic inflammation driven by a combination of host cytokines and tumour derived factors. The ketogenic diet showed promising results, but these are yet to be confirmed in human clinical trials over the long-term. L-carnitine supplementation showed improved quality of life and an increase in lean body mass. As a first step towards preventing and managing pancreatic cancer cachexia, nutritional support should be provided through counselling and the provision of oral nutritional supplements to prevent and minimise loss of lean body mass.

Nutrition and Cancercapsaicin Treatment Reduces Tumor Growth, Tumor Cell Proliferation Ex Vivo and Partially Reverses Cancer Cachexia in Walker 256 Tumor-Bearing Rats

Capsaicin (trans-8-methyl-n-vanillyl-6-nonenamide) is the main pungent component found in hot peppers.

AIM

In this study, we investigated the effect of capsaicin treatment on tumor growth and the metabolic indicators of cachexia in Walker 256 tumor-bearing rats.

METHODS

Male Wistar rats were inoculated subcutaneously in the right flank with 1 ml of a sterile suspension of 3 × 10⁷ Walker tumor cells. The treated groups received capsaicin intraperitoneal 5 mg/kg body weight for 13 days.

RESULTS

The tumor weight on Day 14 in the non-treated group was 18 g. The rats also had a body weight loss, hypoglycemia, hyperlactacidemia, hypertriacylglycerolemia, and a depletion in glycogen storage. Treatment with capsaicin decreased tumor growth by 49% and a reversal of triacylglycerol serum. We also found a 32% reduction in tumor cell proliferation ex vivo. Lactate serum concentrations and body weight were lower but did not reach control levels.

CONCLUSION

The treatment with capsaicin reduces tumor growth and cellular proliferation along with increased apoptosis and partial cachexia reversal.

Supplementation with beta-hydroxy-beta-methylbutyrate impacts glucose homeostasis and increases liver size in trained mice

β-hydroxy-β-methyl butyrate (HMB) is a bioactive metabolite derived from the amino acid leucine, usually applied for muscle mass increase during physical training, as well as for muscle mass maintenance in debilitating chronic diseases. The hypothesis of the present study is that HMB is a safe supplement for muscle mass gain by strength training. Based on this, the objective was to measure changes in body composition, glucose homeostasis and hepatic metabolism of HMB supplemented mice during strength training. Two of four groups of male mice (n = 6/group) underwent an 8-week training period session (climbing stairs) with or without HMB supplementation (190 mg/kgBW per day). We observed lower body mass gain (4.9 ± 0.43% versus 1.2 ± 0.43, p < 0.001) and increased liver mass (40.9 ± 0.9 mg/gBW versus 44.8 ± 1.3, p < 0.001) in the supplemented trained group compared with the non-supplemented groups. The supplemented trained group had an increase in relative adipose tissue mass (12.4 ± 0.63 mg/gBW versus 16.1 ± 0.88, P < 0.01) compared to the non-supplemented untrained group, and an increase in fasting blood glucose (111 ± 4.58 mg/dL versus 122 ± 3.70, P < 0.05) and insulin resistance (3.79 ± 0.19 % glucose decay/min versus 2.45 ± 0.28, P < 0.05) comparing with non-supplemented trained group. Adaptive heart hypertrophy was observed only in the non-supplemented trained group (4.82 ± 0.05 mg/gBW versus 5.12 ± 0.13, P < 0.05). There was a higher hepatic insulin-like growth factor-1 expression (P = 0.002) in supplemented untrained comparing with non-supplemented untrained group. Gene expression of gluconeogenesis regulatory factors was increased by training and reduced by HMB supplementation. These results confirm that HMB supplementation associated with intensive training protocol drives changes in glucose homeostasis and liver metabolism in mice.

Beta-Hydroxy-Beta-Methyl-Butyrate, L-glutamine, and L-arginine Supplementation Improves Radiation-Induce Acute Intestinal Toxicity

We aimed to evaluate effects of β-hydroxy-β-methylbutyrate, L-glutamine, and L-arginine (HMB/GLN/ARG) on radiation-induced acute intestinal toxicity. Forty rats were divided into four groups: group (G) 1 was defined as control group, and G2 was radiation therapy (RT) control group. G3 and G4 were HMB/GLN/ARG control and RT plus HMB/GLN/ARG groups, respectively. HMB/GLN/ARG started from day of RT and continued until the animals were sacrificed 10 days after RT. The extent of surface epithelium smoothing, villous atrophy, lamina propria inflammation, cryptitis, crypt distortion, regenerative atypia, vascular dilatation and congestion, and fibrosis were quantified on histological sections of intestinal mucosa. Statistical analyses were performed using the analysis of variance (ANOVA) test. There were significant differences between study groups regarding extent of surface epithelium smoothing, villous atrophy, lamina propria inflammation, cryptitis and crypt distortion, regenerative atypia, vascular dilatation and congestion, and fibrosis (p values were 0.019 for fibrosis, <.001 for the others). Pair-wise comparisons revealed significant differences regarding surface epithelium smoothing, villous atrophy, lamina propria inflammation, cryptitis, vascular dilatation, and congestion between G2 and G4 (p values were <.001, .033, <.001, .007, and <.001, respectively). Fibrosis score was significantly different only between G1 and G2 (p = .015). Immunohistochemical TGF-β score of G2 was significantly higher than G1 and G3 (p values were .006 and .017, respectively). There was no difference between TGF-β staining scores of G2 and G4. Concomitant use of HMB/GLN/ARG appears to ameliorate radiation-induced acute intestinal toxicity; however, this finding should be clarified with further studies.

Beta-hydroxy-beta-methylbutyrate supplementation and skeletal muscle in healthy and muscle-wasting conditions

Beta-hydroxy-beta-methylbutyrate (HMB) is a metabolite of the essential amino acid leucine that has been reported to have anabolic effects on protein metabolism. The aims of this article were to summarize the results of studies of the effects of HMB on skeletal muscle and to examine the evidence for the rationale to use HMB as a nutritional supplement to exert beneficial effects on muscle mass and function in various conditions of health and disease. The data presented here indicate that the beneficial effects of HMB have been well characterized in strength-power and endurance exercise. HMB attenuates exercise-induced muscle damage and enhances muscle hypertrophy and strength, aerobic performance, resistance to fatigue, and regenerative capacity. HMB is particularly effective in untrained individuals who are exposed to strenuous exercise and in trained individuals who are exposed to periods of high physical stress. The low effectiveness of HMB in strength-trained athletes could be due to the suppression of the proteolysis that is induced by the adaptation to training, which may blunt the effects of HMB. Studies performed with older people have demonstrated that HMB can attenuate the development of sarcopenia in elderly subjects and that the optimal effects of HMB on muscle growth and strength occur when it is combined with exercise. Studies performed under in vitro conditions and in various animal models suggest that HMB may be effective in treatment of muscle wasting in various forms of cachexia. However, there are few clinical reports of the effects of HMB on muscle wasting in cachexia; in addition, most of these studies evaluated the therapeutic potential of combinations of various agents. Therefore, it has not been possible to determine whether HMB was effective or if there was a synergistic effect. Although most of the endogenous HMB is produced in the liver, there are no reports regarding the levels and the effects of HMB supplementation in subjects with liver disease. Several studies have suggested that anabolic effects of HMB supplementation on skeletal muscle do not occur in healthy, non-exercising subjects. It is concluded that (i) HMB may be applied to enhance increases in the mass and strength of skeletal muscles in subjects who exercise and in the elderly and (ii) studies examining the effects of HMB administered alone are needed to obtain conclusions regarding the specific effectiveness in attenuating muscle wasting in various muscle-wasting disorders.

The Effect of a 12-Week Beta-hydroxy-beta-methylbutyrate (HMB) Supplementation on Highly-Trained Combat Sports Athletes: A Randomised, Double-Blind, Placebo-Controlled Crossover Study

The aim of this study was to verify the effect of beta-hydroxy-beta-methylbutyrate (HMB) supplementation on physical capacity, body composition and the value of biochemical parameters in highly-trained combat sports athletes. Forty-two males highly-trained in combat sports were subjected to 12 weeks of supplementation with HMB and a placebo in a randomized, placebo controlled, double-blind crossover manner. Over the course of the experiment, aerobic and anaerobic capacity was determined, while analyses were conducted on body composition and levels of creatine kinase, lactate dehydrogenase, testosterone, cortisol and lactate. Following HMB supplementation, fat-free mass increased (p = 0.049) with a simultaneous reduction of fat mass (p = 0.016) in comparison to placebo. In turn, after HMB supplementation, the following indicators increased significantly in comparison to the placebo: the time to reach ventilatory threshold (p < 0.0001), threshold load (p = 0.017) and the threshold HR (p < 0.0001), as well as anaerobic peak power (p = 0.005), average power (p = 0.029), maximum speed (p < 0.001) and post-exercise lactate concentrations (p < 0.0001). However, when compared to the placebo, no differences were observed in blood marker levels. The results indicate that supplying HMB promotes advantageous changes in body composition and stimulates an increase in aerobic and anaerobic capacity in combat sports athletes.

Muscle wasting and aging: Experimental models, fatty infiltrations, and prevention

Identification of cost-effective interventions to maintain muscle mass, muscle strength, and physical performance during muscle wasting and aging is an important public health challenge. It requires understanding of the cellular and molecular mechanisms involved. Muscle-deconditioning processes have been deciphered by means of several experimental models, bringing together the opportunities to devise comprehensive analysis of muscle wasting. Studies have increasingly recognized the importance of fatty infiltrations or intermuscular adipose tissue for the age-mediated loss of skeletal-muscle function and emphasized that this new important factor is closely linked to inactivity. The present review aims to address three main points. We first mainly focus on available experimental models involving cell, animal, or human experiments on muscle wasting. We next point out the role of intermuscular adipose tissue in muscle wasting and aging and try to highlight new findings concerning aging and muscle-resident mesenchymal stem cells called fibro/adipogenic progenitors by linking some cellular players implicated in both FAP fate modulation and advancing age. In the last part, we review the main data on the efficiency and molecular and cellular mechanisms by which exercise, replacement hormone therapies, and β-hydroxy-β-methylbutyrate prevent muscle wasting and sarcopenia. Finally, we will discuss a potential therapeutic target of sarcopenia: glucose 6-phosphate dehydrogenase.

The ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) attenuates insulin resistance through suppressing GLUT-2 in rat liver

This study investigates the effect of the ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) on insulin resistance induced by high-fructose diet (HFD) in rats. Male Sprague Dawley rats were fed 60% HFD for 12 weeks and HMB (320 mg·kg(-1)·day(-1), orally) for 4 weeks. HFD significantly increased fasting insulin, fasting glucose, glycosylated hemoglobin (HBA1C), liver glycogen content, and homeostasis model assessment of insulin resistance (HOMA-IR) index, while it decreased glucose and insulin tolerance. Furthermore, HFD significantly increased serum triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and very low density lipoprotein cholesterol (VLDL-C) levels, while it significantly decreased high density lipoprotein cholesterol (HDL-C). Moreover, HFD significantly increased mRNA expression of glucose transporter type-2 (GLUT-2), the mammalian target of rapamycin (mTOR), and sterol regulatory element-binding protein-1c (SREBP-1c) but decreased peroxisome proliferator-activated receptor-alpha (PPAR-α) in liver. Aortic relaxation to acetylcholine (ACh) was impaired and histopathology showed severe hepatic steatosis. HMB significantly increased insulin tolerance and decreased fasting insulin, HOMA-IR, HBA1C, hepatic glycogen content, serum TG, LDL-C, and VLDL-C. Additionally, HMB enhanced ACh-induced relaxation, ameliorated hepatic steatosis, and decreased mRNA expression of GLUT-2. In conclusion, HMB may attenuate insulin resistance and hepatic steatosis through inhibiting GLUT-2 in liver.

An overview of amines as nutritional supplements to counteract cancer cachexia

Cancer cachexia is a complex multifactorial syndrome characterized by loss of skeletal muscle mass (with or without loss of fat mass) that cannot be fully reversed by conventional nutritional support and leads to progressive functional impairment. Recently, some amino acids and other amine dietary supplements have been highlighted in medical field due to positive effects upon diseases evolving skeletal muscle atrophy. Therefore, the aim of this brief review is to discuss the putative application of amines as dietary supplements to counteract skeletal muscle wasting on cancer cachexia. Specifically, we focus in two nutritional supplements: (1) branched-chain amino acids (BCAAs) and (2) creatine. Both BCAAs and creatine may attenuate proteolysis and enhance proteins synthesis in skeletal muscle. Although more experimental studies and clinical trials are still necessary to elucidate this therapeutic application, several evidences have demonstrated that amines supplementation is a promising coadjuvant treatment to cancer cachexia.

Glucose intolerance induced by glucocorticoid excess is further impaired by co-administration with β-hydroxy-β-methylbutyrate in rats

Glucocorticoid (GC) excess alters glucose homeostasis and promotes modifications in murinometric and anthropometric parameters in rodents and humans, respectively. β-hydroxy-β-methylbutyrate (HMB), a leucine metabolite, has been proposed as a nutritional strategy for preventing muscle wasting, but few data regarding its effects on glucose homeostasis are available. Here, we analyzed whether the effects of GC excess on glucose homeostasis may be attenuated or exacerbated by the concomitant ingestion of HMB. Adult Wistar rats (90-days-old) were assigned to four groups: (1) vehicle treated (Ctl), (2) dexamethasone (DEX) treated (Dex), (3) HMB treated (Hmb), and (4) DEX plus HMB treated (DexHmb). Dex groups received DEX (1 mg·kg body weight (BW)−1, intraperitoneal) for 5 consecutive days. HMB groups ingested HMB (320 mg·kg BW−1, oral gavage) for the same 5 days. HMB ingestion did not attenuate the effects of DEX on food intake and body weight loss, changes in masses of several organs, insulin resistance, and glucose intolerance (p > 0.05). In fact, in DexHmb rats, there was increased fasting glycemia and exacerbated glucose intolerance with the main effect attributed to DEX treatment (p < 0.05). HMB exerted no attenuating effect on plasma triacylglycerol levels from DexHmb rats, but it seems to attenuate the lipolysis induced by β-adrenergic stimulation (20 μmol·L−1isoproterenol) in fragments of retroperitoneal adipose tissue from DexHmb rats. Therefore, HMB does not attenuate the diabetogenic characteristics of GC excess. In fact, the data suggest that HMB may exacerbate GC-induced glucose intolerance.

Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials

Beta-hydroxy-beta-methylbutyrate (HMB), a metabolite of the branched-chain amino acid leucine, is extensively used by athletes and bodybuilders in order to increase strength, muscle mass and exercise performance. We performed a systematic review of the clinical literature on the effectiveness of HMB supplementation in healthy and pathological conditions (i.e. training programs, aging, acute and chronic diseases, and after bariatric surgery). We reviewed all clinical trials indexed in Medline that tested HMB supplementation as well as all the experimental data regarding HMB intracellular mechanisms of action. Search terms included: randomized controlled trials, controlled clinical trials, single- and double-blind method, HMB, proteolytic pathways, muscle atrophy, cachexia, and training. We found out 13 studies testing HMB in healthy young trained subjects, 11 in healthy young untrained subjects, 9 in patients affected by chronic diseases (i.e. cancer, HIV, chronic obstructive pulmonary disease), and 6 in elderly subjects. The indexed studies support that HMB is effective in preventing exercise-related muscle damage in healthy trained and untrained individuals as well as muscle loss during chronic diseases. Most of the selected studies showed the effectiveness of HMB in preventing exercise-related muscle damage in healthy trained and untrained individuals as well as muscle loss during chronic diseases. The usual dose of 3 g/day may be routinely recommended to maintain or improve muscle mass and function in health and disease. The safety profile of HMB is unequivocal. Further, well-designed clinical studies are needed to confirm effectiveness and mode of action of HMB, particularly in pathological conditions.

Amelioration of radiation-induced acute inflammation and mucosal atrophy by beta-hydroxy-beta-methylbutyrate, L-glutamıne, and L-argınıne: results of an experimental study

PURPOSE

We aimed to evaluate the effects of β-hydroxy-β-methylbutyrate, L-glutamine, and L-arginine (HMB/Glu/Arg) on radiation-induced acute inflammation and mucosal atrophy in the oral mucosa.

METHODS

Twenty-eight rats were divided into four groups. group (G) 1 was defined as control group, and G2 was the radiation therapy (RT) group. G3 and G4 were HMB/Glu/Arg control and 17 Gy RT plus HMB/Glu/Arg groups, respectively. A single dose of 17 Gy RT was given to the head and neck area, and the active supplement consisting of 5.2 g of HMB, 29.6 g arginine, and 29.6 g of glutamine which was equivalent to 60 kg adult dose was calculated for each rat and administrated orally. HMB/Glu/Arg started from the day of RT and continued until the animals were sacrificed 7 days after the RT. The extent of acute inflammation and mucosal atrophy for each rat was quantified with image analysis of histological sections of the oral mucosa.

RESULTS

There were significant differences in terms of epithelial thickness, subepithelial edema, inflammation, and congestion between all groups (p values were <0.001, 0.003, <0.001, and 0.001 for each parameter, respectively). Using HMB/Glu/Arg alone led to hypertrophic changes in the epithelial layer. Moreover, when used with RT, HMB/Glu/Arg reversed radiation-induced epithelial atrophy (p, 0.006) and decreased radiation-induced inflammation at a significant level (p, 0.007).

CONCLUSION

Concomitant use of HMB/Glu/Arg appears to ameliorate the radiation-induced acute inflammation and mucosal atrophy which represent the early phase of acute oral mucositis; however, this finding should be clarified with further clinical studies.

Effects of dairy consumption on SIRT1 and mitochondrial biogenesis in adipocytes and muscle cells

BACKGROUND

Recent data from this laboratory suggest that components of dairy foods may serve as activators of SIRT1 (Silent Information Regulator Transcript 1), and thereby participate in regulation of glucose and lipid metabolism. In this study, an ex-vivo/in-vitro approach was used to examine the integrated effects of dairy diets on SIRT1 activation in two key target tissues (adipose and muscle tissue).

METHODS

Serum from overweight and obese subjects fed low or high dairy diets for 28 days was added to culture medium (similar to conditioned media) to treat cultured adipocytes and muscle cells for 48 hours.

RESULTS

Treatment with high dairy group conditioned media resulted in 40% increased SIRT1 gene expression in both tissues (p < 0.01) and 13% increased enzyme activity in adipose tissue compared to baseline. This was associated with increased gene expression of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α), nuclear respiratory factor 1 (NRF1), cytochrome oxidase c subunit 7 (Cox 7), NADH dehydrogenase and uncoupling protein 2 (UCP2) in adipocytes as well as uncoupling protein 3 (UCP3), NRF1 and Cox 7 in muscle cells (p < 0.05). Further, direct incubation of physiological concentrations of leucine and its metabolites α-Ketoisocaproic acid (KIC) and β-hydroxy-methylbuteric acid (HMB) with recombinant human SIRT1 enzyme resulted in 30 to 50% increase of SIRT1 activity (p < 0.05).

CONCLUSIONS

These data indicate that dairy consumption leads to systemic effects, which may promote mitochondrial biogenesis in key target tissues such as muscle and adipose tissue both by direct activation of SIRT1 as well as by SIRT1-independent pathways.

Anti-inflammatory therapies in cancer cachexia

Disease progression in cancer is dependent on the complex interaction between the tumor and the host inflammatory response. Indeed, both the tumor and the patient produce cytokines that act on multiple target sites such as bone marrow, myocytes, hepatocytes, adipocytes, endothelial cells and neurons, where they produce a complex cascade of biological responses leading to the wasting associated with cachexia. The cytokines that have been involved in this cachectic response are TNF-alpha, IL-1, IL-6 and interferon-gamma. Interestingly, these cytokines share the same metabolic effects and their activities are closely interrelated. In many cases these cytokines exhibit synergic effects when administered together. Therefore, therapeutic strategies - either nutritional or pharmacological - have been based on either blocking their synthesis or their action.

Composition of the athletes diet

Sports nutrition is a constantly evolving field with many of research papers published annually. However, designing the most suitable sports diet is very difficult. It must be given to the type of training, its duration and intensity, the age and sex of the athlete and also for overall health. The aim of this article is to summarize knowledges about sports nutrition, especially intake of carbohydrates, proteins, fats and dietary supplements and their influence on the performance and recovery of the athlete.

β-Hydroxy-β-methylbutyrate (HMβ) supplementation stimulates skeletal muscle hypertrophy in rats via the mTOR pathway

β-Hydroxy-β-methylbutyrate (HMβ) supplementation is used to treat cancer, sepsis and exercise-induced muscle damage. However, its effects on animal and human health and the consequences of this treatment in other tissues (e.g., fat and liver) have not been examined. The purpose of this study was to evaluate the effects of HMβ supplementation on skeletal muscle hypertrophy and the expression of proteins involved in insulin signalling. Rats were treated with HMβ (320 mg/kg body weight) or saline for one month. The skeletal muscle hypertrophy and insulin signalling were evaluated by western blotting, and hormonal concentrations were evaluated using ELISAs. HMβ supplementation induced muscle hypertrophy in the extensor digitorum longus (EDL) and soleus muscles and increased serum insulin levels, the expression of the mammalian target of rapamycin (mTOR) and phosphorylation of p70S6K in the EDL muscle. Expression of the insulin receptor was increased only in liver. Thus, our results suggest that HMβ supplementation can be used to increase muscle mass without adverse health effects.