Ghrelin for cachexia

Anamorelin Induced Acute Hyperglycemia in a Patient with Advanced Pancreatic Cancer and Diabetes: A Case Report

Anamorelin (ANAM) is a novel ghrelin receptor agonist for the treatment of cancer cachexia. In clinical trials of ANAM, glucose metabolism disorders as adverse effects were relatively frequent, however, when and how they occur remains unclear. Moreover, the safety in patients with pancreatic cancer and/or diabetes has not been clarified because most previous studies focused on patients with non-small cell lung cancer and had excluded patients with poorly controlled diabetes. Herein, a 66-year-old man with advanced pancreatic cancer and diabetes was administered ANAM, and acute hyperglycemia was developed and could be monitored by the self-monitoring of blood glucose (SMBG). Increasing the insulin dose failed to control hyperglycemia adequately, but the hyperglycemia ameliorated quickly after ANAM discontinuation. The continuous glucose monitoring (CGM) revealed that the sensor glucose levels had remained in the high range throughout the day during ANAM administration despite using 1.5 times more insulin. Our report is one of the few that describe the details of ANAM-induced hyperglycemia and provides important information for the safe and effective use of ANAM.

Molecular mechanisms underlying sarcopenia in heart failure

The loss of skeletal muscle, also known as sarcopenia, is an aging-associated muscle disorder that is disproportionately present in heart failure (HF) patients. HF patients with sarcopenia have poor outcomes compared to the overall HF patient population. The prevalence of sarcopenia in HF is only expected to grow as the global population ages, and novel treatment strategies are needed to improve outcomes in this cohort. Multiple mechanistic pathways have emerged that may explain the increased prevalence of sarcopenia in the HF population, and a better understanding of these pathways may lead to the development of therapies to prevent muscle loss. This review article aims to explore the molecular mechanisms linking sarcopenia and HF, and to discuss treatment strategies aimed at addressing such molecular signals.

Evaluation and management of body composition changes in cancer patients

Wasting in cancer patients has long been recognized as a condition that adversely affects cancer patients' quality of life, treatment tolerance, and oncological outcomes. Historically, this condition was mainly evaluated by changes in body weight. However, this approach is not quite accurate because body weight is the overall change of all body compartments. Conditions such as edema and ascites can mask the severity of muscle and adipose tissue depletion. Changes in body composition assessment in cancer patients have historically been underappreciated because of the limited availability of measurement tools. As more evidence highlighting the importance of body composition has emerged, it is imperative to apply a more precise evaluation of nutritional status and a more targeted approach to provide nutritional support for cancer patients. In this review, we will discuss the modalities for evaluating body composition and how to manage body composition changes in cancer patients.

Circulating ghrelin levels in patients with gastric cancer: a systematic review and meta-analysis

Background

Ghrelin plays a critical role in regulating energy metabolism and homeostasis. The association between circulating ghrelin levels and gastric cancer has not been systematically analyzed.

Objective

This work explored the association between circulating ghrelin levels and gastric cancer.

Methods

The literature search for relevant articles published until November 2022 was performed using PubMed, Cochrane Library, EMBASE, and Web of Science with the keywords "ghrelin" and "gastric cancer". Standardized mean differences (SMD) with 95% confidence intervals were used to measure the effectiveness. We assessed pooled data by use of a random-effects model.

Results

Of 5,302 identified studies, nine were included (N=3,196 participants). Circulating ghrelin levels were lower in gastric cancer patients (SMD=-0.255, 95%CI: -0.528 to 0.017, P < 0.00001), but with high heterogeneity (I2 = 88.8%).

Conclusion

The circulating ghrelin levels in patients with gastric cancer were lower than in controls. However, there was heterogeneity among results; therefore, studies with larger sample sizes are recommended.

Update on the treatment of cancer cachexia

Cancer cachexia is a complex multifaceted syndrome involving functional impairment and changes in body composition that cannot be reversed by nutritional support. Cancer cachexia is characterized by decreased skeletal muscle mass, increased lipolysis, and decreased food intake. Cancer cachexia decreases chemotherapy tolerance as well as quality of life. However, because no fully effective interventions are available, cancer cachexia remains an unmet need in cancer treatment. In recent years, several discoveries and treatments for cancer cachexia have been studied, and guidelines have been published. We believe that the development of effective strategies for the diagnosis and treatment of cancer cachexia will lead to breakthroughs in cancer treatment.

The complex pathophysiology of cardiac cachexia: A review of current pathophysiology and implications for clinical practice

Cardiac cachexia is a muscle wasting process that often develops in those with chronic heart failure resulting in weight loss, low levels of physical activity, reduced quality of life, and is associated with a poor prognosis. The pathology of cardiac cachexia is complex with new evidence emerging that implicates several body systems. This review describes the pathophysiology associated with cardiac cachexia and addresses: 1) hormonal changes- neurohormonal abnormalities and metabolic hormone imbalance; 2) mechanisms of muscle wasting in cardiac cachexia, and the integral mechanisms between changed hormones due to cardiac cachexia and muscle wasting processes, and 3) associated abnormalities of gastrointestinal system that contribute to cardiac cachexia. These pleiotropic mechanisms demonstrate the intricate interplay between the affected systems and account for why cardiac cachexia is difficult to manage clinically. This review summarises current pathophysiology of cardiac cachexia and highlights symptoms of cardiac cachexia, implications for clinical practice and research gaps.

Androgen replacement therapy for cancer-related symptoms in male: result of prospective randomized trial (ARTFORM study)

BACKGROUND

Hypogonadism associated with cancer is reported to cause cachexia and a variety of physical and psychological symptoms. This study aims to evaluate whether androgen replacement therapy can improve cancer-related symptoms in male advanced cancer patients.

METHODS

An investigator-initiated, prospective, and randomized controlled study was conducted. Patients with low serum testosterone levels (total or free testosterone levels were <2.31 ng/mL or <11.8 pg/mL, respectively) were randomly assigned to the control or testosterone enanthate administration (testosterone group) groups. Testosterone enanthate was injected into the muscle tissue at a dose of 250 mg every 4 weeks (baseline, week 4, and week 8). Differences in quality of life questionnaires and cachexia-related serum protein levels between groups were assessed.

RESULTS

This study enrolled and randomized 106 and 81 patients, respectively. Moreover, 41 and 40 patients were in the control and testosterone groups, respectively. Although no significant differences in the change of subscales and total scores in Functional Assessment of Anorexia/Cachexia Treatment were noted from the baseline between the two groups, the testosterone group showed a significantly better change in the 'unhappiness' item of the Edmonton Symptom Assessment System at week 12 compared with baseline versus the control group (-1.4 and 0.0 points, respectively; mean, P = 0.007). No significant differences exist in the change of serum interleukin-6 and insulin-like growth factor-1 levels at week 12 from the baseline between the control and testosterone groups. Consequently, the testosterone group significantly inhibited the change in serum tumour necrotic factor-α level at week 12 from the baseline compared with the control group (+0.4 and +0.1 pg/mL, respectively; mean, P = 0.005).

CONCLUSIONS

Although testosterone enanthate did not improve most of the items in health-related quality of life questionnaires, testosterone enanthate induced a significantly better change in the 'unhappiness' item at week 12 compared with the control. Testosterone enanthate may be a potential treatment option for male advanced cancer patients.

Diet-related interventions for cancer-associated cachexia

PURPOSE

Cancer-associated cachexia is a common condition in patients with advanced cancer, and is associated with extreme and involuntary weight loss and irreversible muscle wasting. Despite its high morbidity and mortality, there is no known treatment to reverse its effects. Thus, there is increasing interest in whether diet and exercise can assist in the minimization of cancer-associated cachexia.

METHODS

We reviewed the literature on the impact of dietary patterns, dietary components, and exercise on the progress and severity of cancer cachexia.

RESULTS

Although most studies have produced inconclusive or controversial findings, some promising studies using animal models and early human clinical trials suggest that dietary and physical therapy interventions may alleviate cancer-associated cachexia. Moreover, many studies suggest that controlling diet and exercise nevertheless improved the quality of life (QoL) for cancer patients with cachexia.

CONCLUSION

Ongoing studies will continue to examine whether different forms of multimodal therapy-combinations of cancer treatment, dietary regimens, anti-inflammatory therapy, and physical therapy-are effective methods to improve outcomes in advanced cancer patients with cachexia. Moreover, future studies should examine the effects of such interventions on long-term QoL and establish nutritional guidelines for the management of cancer-associated cachexia.

Targeting the JAK2/STAT3 Pathway-Can We Compare It to the Two Faces of the God Janus?

Muscle cachexia is one of the most critical unmet medical needs. Identifying the molecular background of cancer-induced muscle loss revealed a promising possibility of new therapeutic targets and new drug development. In this review, we will define the signal transducer and activator of transcription 3 (STAT3) protein's role in the tumor formation process and summarize the role of STAT3 in skeletal muscle cachexia. Finally, we will discuss a vast therapeutic potential for the STAT3-inhibiting single-agent treatment innovation that, as the desired outcome, could block tumor growth and generally prevent muscle cachexia.

Supplementary Oral Anamorelin Mitigates Anorexia and Skeletal Muscle Atrophy Induced by Gemcitabine Plus Cisplatin Systemic Chemotherapy in a Mouse Model

Chemotherapy-induced adverse effects can reduce the relative dose intensity and quality of life. In this study, we investigated the potential benefit of supplementary anamorelin and 5-aminolevulinic acid (5-ALA) as preventive interventions against a gemcitabine and cisplatin (GC) combination chemotherapy-induced adverse effects in a mouse model. Non-cancer-bearing C3H mice were randomly allocated as follows and treated for 2 weeks—(1) non-treated control, (2) oral anamorelin alone, (3) oral 5-ALA alone, (4) gemcitabine and cisplatin (GC) chemotherapy, (5) GC plus anamorelin, and (6) GC plus 5-ALA. GC chemotherapy significantly decreased body weight, food intake, skeletal muscle mass and induced severe gastric mucositis, which resulted in decreased ghrelin production and blood ghrelin level. The supplementation of oral anamorelin to GC chemotherapy successfully mitigated decrease of food intake during the treatment period and body weight loss at day 8. In addition, analysis of the resected muscles and stomach revealed that anamorelin suppressed chemotherapy-induced skeletal muscle atrophy by mediating the downregulation of forkhead box protein O-1 (FOXO1)/atrogin-1 signaling and gastric damage. Our findings suggest the preventive effect of anamorelin against GC combination chemotherapy, which was selected for patients with some types of advanced malignancies in clinical practice.

Cachexia in Cancer Patients: Systematic Literature Review

Introduction Cachexia in cancer patients, especially in advanced stage, is recently known as an emerging problem. Cachexia occurs in about half of all patients with neoplastic disease. The diagnosis of cachexia needs comprehensive evaluation of body weight and body composition for several months. Cachexia will give negative impacts such as increased mortality, chemotoxicity, and decreased quality of life. Here, we review the current evidence describing the definition, stages, mechanisms, diagnosis and treatment of cachexia in cancer patients.

Methods We identified 75 studies and/or review articles evaluating cachexia and weight loss in cancer patients by searching PubMed and EMBASE databases.

Results Cachexia is reported across all stages and types of cancers. The most recent definition of cachexia is reported in a 2011 paper by International Consensus. The mechanism of cachexia in cancer is complex and involved many factors which elaborate together to produce cachexia. The diagnostic evaluation and cut-off measurement of cachexia, especially in cancer varied across studies. The loss of weight that happens during chemotherapy will make a poor prognosis. Cachexia can worsen chemotherapy toxicity. Combination of dietary modification and exercise with supplementation of medication that control appetite and inflammation are important in the management of cachexia in cancer patients.

Conclusion Patients with cancer are the population at risk for developing cachexia before and after chemotherapy. Cachexia diagnosis needs evaluation of body weight and body composition. Nonpharmacological treatments, such as dietary modification and physical exercise, are the best strategy to reduce cachexia in cancer patients.

Cancer Cachexia and Related Metabolic Dysfunction

Cancer cachexia is a complex multifactorial syndrome marked by a continuous depletion of skeletal muscle mass associated, in some cases, with a reduction in fat mass. It is irreversible by nutritional support alone and affects up to 74% of patients with cancer-dependent on the underlying type of cancer-and is associated with physical function impairment, reduced response to cancer-related therapy, and higher mortality. Organs, like muscle, adipose tissue, and liver, play an important role in the progression of cancer cachexia by exacerbating the pro- and anti-inflammatory response initially activated by the tumor and the immune system of the host. Moreover, this metabolic dysfunction is produced by alterations in glucose, lipids, and protein metabolism that, when maintained chronically, may lead to the loss of skeletal muscle and adipose tissue. Although a couple of drugs have yielded positive results in increasing lean body mass with limited impact on physical function, a single therapy has not lead to effective treatment of this condition. Therefore, a multimodal intervention, including pharmacological agents, nutritional support, and physical exercise, may be a reasonable approach for future studies to better understand and prevent the wasting of body compartments in patients with cancer cachexia.

Attribution of Ghrelin to Cancer; Attempts to Unravel an Apparent Controversy

Ghrelin is an endogenous peptide hormone mainly produced in the stomach. It has been known to regulate energy homeostasis, stimulate secretion of growth hormone, and mediate many other physiologic effects. Various effects attributed to ghrelin contribute to many aspects of cancer development and progression. Accordingly, a large body of evidence has emerged about the association of ghrelin with several types of cancer in scales of cell-line, animal, and human studies. However, existing data are controversial. This controversy occurs in two main domains: one is the controversial results in local effects of ghrelin on different types of human cancer cell-lines; the second is the apparent disagreement in the results of in-vitro and clinical studies that investigated ghrelin association to one type of cancer. These inconsistencies have hampered the indications to consider ghrelin as a potential tumor biomarker or therapeutic agent in cancer patients. Previous studies have reviewed different parts of current literature about the ghrelin-cancer relationship. Although they have highlighted these controversial results in various ways, no specific recommendations have been given to address it. In this study, we comprehensively reviewed in-vitro, in-vivo, and clinical studies and attempted to use the following approaches to unravel the inconsistencies detected: (a) to distinguish local and systemic effects of ghrelin in interpreting its summary clinical role in each cancer; (b) scrutinizing factors that regulate local effects of ghrelin and could justify different effects of ghrelin on different cancer cell-lines. These approaches could have notable implications for future in-vitro and clinical studies.

The role of adiponectin, LEPTIN, and ghrelin in the progress and prognosis of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Dysregulation of adipokine pathways is implicated in the carcinogenesis and ALL. The aim of this study is to present the most recent data available regarding the role of leptin, adiponectin and ghrelin in the pathogenesis and prognosis of ALL. The PubMed database was searched using 'Leptin', 'Adiponectin', 'Ghrelin', 'Cancer', 'Children' and 'Acute Lymphoblastic Leukemia' as keywords. The majority of the studies indicated that leptin levels are increased and adiponectin levels are decreased in ALL children at diagnosis, as well as in ALL survivors. Ghrelin levels were found to be lower at diagnosis and progressively increased during treatment. Further research is warranted, as the heterogeneity of the current studies, various treatment protocols and differences in sample sizes make it difficult to deduce solid conclusions regarding the role of adipokines in ALL.

Eradication therapy for Helicobacter pylori infection improves nutrition status in Japanese hemodialysis patients: a pilot study

Plasma ghrelin level is influenced by Helicobacter pylori (H. pylori) status and the severity of gastric mucosal atrophy, and the ghrelin level is associated with nutrition status in hemodialysis patients. Here, we investigated the efficacy of H. pylori eradication therapy in improving nutrition status in relation to the ghrelin level in H. pylori-positive hemodialysis patients. Of H. pylori-positive patients receiving hemodialysis at 8 dialysis center, 21 patients underwent gastroduodenoscopy for evaluation of the severity of gastric atrophy, and nutrition markers and plasma ghrelin levels before and 1 year after H. pylori eradication therapy were evaluated. Serum cholinesterase level was significantly increased after H. pylori eradication compared with the level before eradication (303.2 ± 76.0 vs 287.3 ± 68.1 IU/L, p = 0.029). In particular, cholesterol (before, 196.6 ± 23.2 mg/dl; after, 206.1 ± 25.9 mg/dl, p = 0.042) and cholinesterase levels (before, 296.9 ± 70.8 IU/L; after, 316.4 ± 73.8 IU/L, p = 0.049) increased more strongly in patients with mild–moderate atrophy than those with severe atrophy, irrespective of improvement of plasma acyl-ghrelin and desacyl-ghrelin levels after eradication therapy. In conclusion, H. pylori eradication may improve nutrition status by increasing serum cholinesterase and cholesterol levels in hemodialysis patients, especially those with mild and moderate gastric mucosal atrophy.

Androgen replacement therapy for cancer-related symptoms in male advanced cancer patients: study protocol for a randomised prospective trial (ARTFORM study)

Recent studies reveal that hypogonadism with low serum androgen levels is associated with advanced cancer and induction of most cancer-related symptoms. We designed an ARTFORM study to evaluate the efficacy of androgen replacement therapy in male advanced cancer patients. The ARTFORM study is an investigator-initiated, randomised controlled trial comparing intramuscle injection of testosterone enanthate with non-administration in male advanced cancer patients with non-curative locally advanced or metastatic lesions. Serum total and free testosterone levels are measured and patients with low testosterone level are randomised. The primary endpoint is the difference in validated health-related quality of life questionnaires at week 12. Trial registration of the ARTFORM study is assigned to University hospital Medical Information Network, Center identifier UMIN 000010939. J. Med. Invest. 64: 202-204, August, 2017.

Nutrition status and Helicobacter pylori infection in patients receiving hemodialysis

Chronic kidney disease (CKD) patients receiving hemodialysis (HD) often develop gastrointestinal abnormalities over their long treatment period. In general, prognosis in such patients is poor due to the development of protein-energy wasting (PEW). Therefore, it is important to clarify the etiology of PEW and to establish better strategies to deal with this condition. Chronic Helicobacter pylori (H. pylori) infection in the gastric mucosa has a close association with not only the development of peptic ulcer disease and gastric cancer, but is also associated with abnormal plasma and gastric mucosal ghrelin levels that are seen in malnutrition. It is unclear whether H. pylori infection of the gastric mucosa is directly associated with prognosis in HD patients by affecting ghrelin levels. Recent studies show that the prevalence of H. pylori infection in HD patients is significantly lower than in subjects with normal renal function. In the natural history of H. pylori infection in HD patients, the prevalence of infection decreases as the length of time on HD increases. The severity of gastric mucosal atrophy has been suggested as the major determinant of ghrelin levels in these patients, and eradication therapy of H. pylori improves nutritional status by increasing serum cholinesterase and cholesterol levels, especially in patients with mild-to-moderate gastric mucosal atrophy. Prompt H. pylori eradication to inhibit the progress of gastric atrophy may be required to prevent this decrease in ghrelin levels and subsequent PEW and improve the prognosis of HD patients by improving their nutritional status.

Ghrelin for the management of cachexia associated with cancer

BACKGROUND

Cancer sufferers are amongst the most malnourished of all the patient groups. Studies have shown that ghrelin, a gut hormone can be a potential therapeutic agent for cachexia (wasting syndrome) associated with cancer. A variety of mechanisms of action of ghrelin in people with cancer cachexia have been proposed. However, safety and efficacy of ghrelin for cancer-associated cachexia have not been systematically reviewed. The aim of this review was to assess whether ghrelin is associated with better food intake, body composition and survival than other options for adults with cancer cachexia.

OBJECTIVES

To assess the efficacy and safety of ghrelin in improving food intake, body composition and survival in people with cachexia associated with cancer.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase without language restrictions up to July 2017. We also searched for ongoing studies in trials registers, performed handsearching, checked bibliographic references of relevant articles and contacted authors and experts in the field to seek potentially relevant research. We applied no restrictions on language, date, or publication status.

SELECTION CRITERIA

We included randomised controlled (parallel-group or cross-over) trials comparing ghrelin (any formulation or route of administration) with placebo or an active comparator in adults (aged 18 years and over) who met any of the international criteria for cancer cachexia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility. Two review authors then extracted data and assessed the risk of bias for individual studies using standard Cochrane methodology. For dichotomous variables, we planned to calculate risk ratio with 95% confidence intervals (CI) and for continuous data, we planned to calculate mean differences (MD) with 95% CI. We assessed the evidence using GRADE and created 'Summary of findings' tables.

MAIN RESULTS

We screened 926 individual references and identified three studies that satisfied the inclusion criteria. Fifty-nine participants (37 men and 22 women) aged between 54 and 78 years were randomised initially, 47 participants completed the treatment. One study had a parallel design and two had a cross-over design. The studies included people with a variety of cancers and also differed in the dosage, route of administration, frequency and duration of treatment.One trial, which compared ghrelin with placebo, found that ghrelin improved food intake (very low-quality evidence) and had no adverse events (very low-quality evidence). Due to unavailability of data we were unable to report on comparisons for ghrelin versus no treatment or alternative experimental treatment modalities, or ghrelin in combination with other treatments or ghrelin analogues/ghrelin mimetics/ghrelin potentiators. Two studies compared a higher dose of ghrelin with a lower dose of ghrelin, however due to differences in study designs and great diversity in the treatment provided we did not pool the results. In both trials, food intake did not differ between participants on higher-dose and lower-dose ghrelin. None of the included studies assessed data on body weight. One study reported higher adverse events with a higher dose as compared to a lower dose of ghrelin.All studies were at high risk of attrition bias and bias for size of the study. Risk of bias in other domains was unclear or low.We rated the overall quality of the evidence for primary outcomes (food intake, body weight, adverse events) as very low. We downgraded the quality of the evidence due to lack of data, high or unclear risk of bias of the studies and small study size.

AUTHORS' CONCLUSIONS

There is insufficient evidence to be able to support or refute the use of ghrelin in people with cancer cachexia. Adequately powered randomised controlled trials focusing on evaluation of safety and efficacy of ghrelin in people with cancer cachexia is warranted.

Drugs of Muscle Wasting and Their Therapeutic Targets

Muscle wasting and weakness such as cachexia, atrophy, and sarcopenia are characterized by marked decreases in the protein content, myonuclear number, muscle fiber size, and muscle strength. This chapter focuses on the recent advances of pharmacological approach for attenuating muscle wasting.A myostatin-inhibiting approach is very intriguing to prevent sarcopenia but not muscular dystrophy in humans. Supplementation with ghrelin is also an important candidate to combat sarcopenia as well as cachexia. Treatment with soy isoflavone, trichostatin A (TSA), and cyclooxygenase 2 (Cox2) inhibitors seems to be effective modulators attenuating muscle wasting, although further systematic research is needed on this treatment in particular concerning side effects.

Development of coated liposomes loaded with ghrelin for nose-to-brain delivery for the treatment of cachexia

The aim of the present study was to develop a ghrelin-containing formulation based on liposomes coated with chitosan intended for nose–brain delivery for the treatment of cachexia. Among the three types of liposomes developed, anionic liposomes provided the best results in terms of encapsulation efficiency (56%) and enzymatic protection against trypsin (20.6% vs 0% for ghrelin alone) and carboxylesterase (81.6% vs 17.2% for ghrelin alone). Ghrelin presented both electrostatic and hydrophobic interactions with the anionic lipid bilayer, as demonstrated by isothermal titration calorimetry. Then, anionic liposomes were coated with N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride. The coating involved a size increment from 146.9±2.7 to 194±6.1 nm, for uncoated and coated liposomes, respectively. The ζ-potential was similarly increased from -0.3±1.2 mV to 6±0.4 mV before and after coating, respectively. Chitosan provided mucoadhesion, with an increase in mucin adsorption of 22.9%. Enhancement of permeation through the Calu3 epithelial monolayer was also observed with 10.8% of ghrelin recovered in the basal compartment in comparison to 0% for ghrelin alone. Finally, aerosols generated from two nasal devices (VP3 and SP270) intended for aqueous dispersion were characterized with either coated or uncoated liposomes. Contrarily to the SP270 device, VP3 device showed minor changes between coated and uncoated liposome aerosols, as shown by their median volume diameters of 38.4±5.76 and 37.6±5.74 µm, respectively. Overall, the results obtained in this study show that the developed formulation delivered by the VP3 device can be considered as a potential candidate for nose–brain delivery of ghrelin.

Protein calorie malnutrition, nutritional intervention and personalized cancer care

Cancer patients often experience weight loss caused by protein calorie malnutrition (PCM) during the course of the disease or treatment. PCM is expressed as severe if the patient has two or more of the following characteristics: obvious significant muscle wasting, loss of subcutaneous fat; nutritional intake of <50% of recommended intake for 2 weeks or more; bedridden or otherwise significantly reduced functional capacity; weight loss of >2% in 1 week, 5% in 1 month, or 7.5% in 3 months. Cancer anorexia-cachexia syndrome (CACS) is a multifactorial condition of advanced PCM associated with underlying illness (in this case cancer) and is characterized by loss of muscle with or without loss of fat mass. Cachexia is defined as weight loss of more than 5% of body weight in 12 months or less in the presence of chronic disease. Hence with a chronic illness on board even a small amount of weight loss can open the door to cachexia. These nutritional challenges can lead to severe morbidity and mortality in cancer patients. In the clinic, the application of personalized medicine and the ability to withstand the toxic effects of anti-cancer therapies can be optimized when the patient is in nutritional homeostasis and is free of anorexia and cachexia. Routine assessment of nutritional status and appropriate intervention are essential components of the effort to alleviate effects of malnutrition on quality of life and survival of patients.

The emerging role of anamorelin hydrochloride in the management of patients with cancer anorexia-cachexia

Cancer cachexia affects many patients with advanced cancer. This multifactorial syndrome, which involves loss of muscle mass and body weight, profoundly affects patients' physical functioning and quality of life. Pharmacologic interventions that target weight loss and also improve patient-reported measures are required. Anamorelin hydrochloride is an oral ghrelin receptor agonist for the treatment of cancer anorexia-cachexia that stimulates release of growth hormone and insulin-like growth factor 1, and improves food intake and body weight. Phase II and III trials have demonstrated that anamorelin increases body muscle and fat composition, and improves patient-reported appetite and quality of life. Anamorelin shows promise as an anabolic agent with benefits maintained over time, without the virilizing side effects of other anabolic medications.

Growth hormone secretagogues prevent dysregulation of skeletal muscle calcium homeostasis in a rat model of cisplatin-induced cachexia

BACKGROUND

Cachexia is a wasting condition associated with cancer types and, at the same time, is a serious and dose-limiting side effect of cancer chemotherapy. Skeletal muscle loss is one of the main characteristics of cachexia that significantly contributes to the functional muscle impairment. Calcium-dependent signaling pathways are believed to play an important role in skeletal muscle decline observed in cachexia, but whether intracellular calcium homeostasis is affected in this situation remains uncertain. Growth hormone secretagogues (GHS), a family of synthetic agonists of ghrelin receptor (GHS-R1a), are being developed as a therapeutic option for cancer cachexia syndrome; however, the exact mechanism by which GHS interfere with skeletal muscle is not fully understood.

METHODS

By a multidisciplinary approach ranging from cytofluorometry and electrophysiology to gene expression and histology, we characterized the calcium homeostasis in fast-twitch extensor digitorum longus (EDL) muscle of adult rats with cisplatin-induced cachexia and established the potential beneficial effects of two GHS (hexarelin and JMV2894) at this level. Additionally, in vivo measures of grip strength and of ultrasonography recordings allowed us to evaluate the functional impact of GHS therapeutic intervention.

RESULTS

Cisplatin-treated EDL muscle fibres were characterized by a ~18% significant reduction of the muscle weight and fibre diameter together with an up-regulation of atrogin1/Murf-1 genes and a down-regulation of Pgc1-a gene, all indexes of muscle atrophy, and by a two-fold increase in resting intracellular calcium, [Ca2+ ]i , compared with control rats. Moreover, the amplitude of the calcium transient induced by caffeine or depolarizing high potassium solution as well as the store-operated calcium entry were ~50% significantly reduced in cisplatin-treated rats. Calcium homeostasis dysregulation parallels with changes of functional ex vivo (excitability and resting macroscopic conductance) and in vivo (forelimb force and muscle volume) outcomes in cachectic animals. Administration of hexarelin or JMV2894 markedly reduced the cisplatin-induced alteration of calcium homeostasis by both common as well as drug-specific mechanisms of action. This effect correlated with muscle function preservation as well as amelioration of various atrophic indexes, thus supporting the functional impact of GHS activity on calcium homeostasis.

CONCLUSIONS

Our findings provide a direct evidence that a dysregulation of calcium homeostasis plays a key role in cisplatin-induced model of cachexia gaining insight into the etiopathogenesis of this form of muscle wasting. Furthermore, our demonstration that GHS administration efficaciously prevents cisplatin-induced calcium homeostasis alteration contributes to elucidate the mechanism of action through which GHS could potentially ameliorate chemotherapy-associated cachexia.

Prognostic Significance of Preoperative and Postoperative Plasma Levels of Ghrelin in Gastric Cancer: 3-Year Survival Study

OBJECTIVES:

We aimed to investigate prognostic effects of plasma levels of ghrelin before and after gastrectomy in gastric cancer (GC).

METHODS:

We followed 81 GC patients up to 3 years in this study. They were candidates for curative gastrectomy with or without neoadjuvant chemotherapy. Plasma levels of total and active ghrelins before and after the operation were assessed. Association of plasma levels of ghrelin with survival were assessed and adjusted for other potential prognostic factors using Cox regression analyses.

RESULTS:

Both total and active ghrelins dropped after gastrectomy (P<0.001 for both). Multiple Cox models revealed worse survival for patients with postoperative total ghrelins below median (hazards ratio (HR)=2.33, 95% confidence interval (CI): 1.01–5.41) or 25th percentile (HR=4.29, 95% CI: 1.48–12.44) compared with patients with higher ghrelin levels. In case of preoperative total ghrelin, patients with either second or third quartiles of plasma ghrelin showed worse survival compared with patients with the lowest quartile (HR=2.67, 95% CI: 1.11–6.38 for second quartile, and HR=2.32, 95% CI: 1.01–5.35 for third quartile vs. the lowest quartile). However, there was no difference between patients with the highest and lowest quartiles (HR=0.78, 95% CI: 0.22–2.73). Similar pattern was observed for preoperative active ghrelin (HR=4.92, 95% CI: 1.80–13.54 for second quartile, and HR=2.87, 95% CI: 1.11–7.38 for third quartile vs. the lowest quartile). Advanced TNM stage (HR=4.88, 95% CI: 1.10–21.77), cachexia (HR=2.99, 95% CI: 1.35–6.63), and receiving no neoadjuvant chemotherapy (HR=2.02, 95% CI: 1.04–3.92) were other poor prognostic factors.

CONCLUSIONS:

Preoperative and postoperative plasma levels of ghrelin could predict survival of GC patients with different patterns. This prognostic effect was independent of stage and cachexia. Measurement of plasma ghrelin in GC patients could complement conventional staging for more precise risk-stratification of the patients. Extrinsic admirations of ghrelin after total gastrectomy has potentials to improve survival of GC patients.

The effect of hydro-alcoholic extract of Achillea millefolium on appetite hormone in rats

OBJECTIVE

Achillea millefolium (A. millefolium) is known as an orexigenic herb in Iranian traditional medicine. In this study, the possible orexigenic effect of hydro-alcoholic extract of A. millefolium was investigated by measuring plasmaghrelin level.

MATERIALS AND METHODS

Thirty male Wistar rats were divided into five groups. Control group received water. Treatment groups received 50, 100 or 150 mg/kg of A. millefolium extract for 7 days via gavage. Before the intervention, daily amount of the food eaten by each rat was measured for 10 days. During the investigation, the amount of energy intake of each rat was also estimated 1, 2, 4, 6 and 24 hr after each intake, for 7 days. Later, the orexigenic dose of extract and distilled water was fed to two separate groups of 6 male Wistar rats. Plasma ghrelin level was measured 0.5, 1, 2 and 4 hrafter extract intake.

RESULTS

The change in energy intake after treatment by 50and 100mg/kg of the extract was significantly higher than other groups (p<0.001).Administration of Achillea 100mg/kg significantly (p<0.05) decreased ghrelin level one hrafter intervention but there was no significant (p>0.05) difference among control and treated group.

CONCLUSION

This study indicated that A. millefolium had positive dose-related effects on appetite in rats. It seems that the orexigenicactivity of extract was not related to changes in plasma ghrelin levels.

Relationship between ghrelin, Helicobacter pylori and gastric mucosal atrophy in hemodialysis patients

AIM

To investigate the relationship between plasma ghrelin level, Helicobacter pylori (H. pylori) infection status and the severity of atrophy in hemodialysis patients.

METHODS

One hundred eights patients who received hemodialysis and 13 non-hemodialysis H. pylori-negative controls underwent gastroduodenoscopy to evaluate the severity of gastric atrophy. Serum levels of pepsinogen (PG) were measured as serum markers of gastric atrophy. H. pylori infection was evaluated by anti-H. pylori IgG antibody, rapid urease test and culture test. We classified H. pylori infection status as non-infection, present infection and past infection. In addition, plasma acyl-ghrelin and desacyl-ghrelin levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Infection rate of H. pylori was 45.4% (49/108). Acyl-ghrelin level in the non-infection group (39.4 ± 23.0 fmol/mL) was significantly higher than in the past (23.4 ± 19.9 fmol/mL, P = 0.005) and present infection groups (19.5 ± 14.0 fmol/mL, P < 0.001). Furthermore, desacyl-ghrelin level in the non-infection group (353.2 ± 190.2 fmol/mL) was significantly higher than those in the past (234.9 ± 137.5 fmol/mL, P = 0.008) and present infection groups (211.8 ± 124.2 fmol/mL, P < 0.001). Acyl-ghrelin was positively correlated with the PG I level and PG I/II ratio (|R| = 0.484, P < 0.001 and |R| = 0.403, P < 0.001, respectively). Both ghrelins were significantly decreased in accordance with the progress of endoscopic atrophy (both P < 0.001) and acyl-ghrelin was significantly lower in patients with mild, moderate and severe atrophy (24.5 ± 23.1 fmol/mL, 20.2 ± 14.9 fmol/mL and 18.3 ± 11.8 fmol/mL) than in those with non-atrophy (39.4 ± 22.2 fmol/mL, P = 0.039, P = 0.002 and P < 0.001, respectively).

CONCLUSION

In hemodialysis patients, plasma ghrelin level was associated with the endoscopic and serological severity of atrophy related to H. pylori infection.

Increased Ghrelin but Low Ghrelin-Reactive Immunoglobulins in a Rat Model of Methotrexate Chemotherapy-Induced Anorexia

Background and aims

Cancer chemotherapy is commonly accompanied by mucositis, anorexia, weight loss, and anxiety independently from cancer-induced anorexia–cachexia, further aggravating clinical outcome. Ghrelin is a peptide hormone produced in gastric mucosa that reaches the brain to stimulate appetite. In plasma, ghrelin is protected from degradation by ghrelin-reactive immunoglobulins (Ig). To analyze possible involvement of ghrelin in the chemotherapy-induced anorexia and anxiety, gastric ghrelin expression, plasma levels of ghrelin, and ghrelin-reactive IgG were studied in rats treated with methotrexate (MTX).

Methods

Rats received MTX (2.5 mg/kg, subcutaneously) for three consecutive days and were killed 3 days later, at the peak of anorexia and weight loss. Control rats received phosphate-buffered saline. Preproghrelin mRNA expression in the stomach was analyzed by in situ hybridization. Plasma levels of ghrelin and ghrelin-reactive IgG were measured by immunoenzymatic assays and IgG affinity kinetics by surface plasmon resonance. Anxiety- and depression-like behaviors in MTX-treated anorectic and in control rats were evaluated in the elevated plus-maze and the forced-swim test, respectively.

Results

In MTX-treated anorectic rats, the number of preproghrelin mRNA-producing cells was found increased (by 51.3%, p < 0.001) as well were plasma concentrations of both ghrelin and des-acyl-ghrelin (by 70.4%, p < 0.05 and 98.3%, p < 0.01, respectively). In contrast, plasma levels of total IgG reactive with ghrelin and des-acyl-ghrelin were drastically decreased (by 87.2 and 88.4%, respectively, both p < 0.001), and affinity kinetics of these IgG were characterized by increased small and big Kd, respectively. MTX-treated rats displayed increased anxiety- but not depression-like behavior.

Conclusion

MTX-induced anorexia, weight loss, and anxiety are accompanied by increased ghrelin production and by a decrease of ghrelin-reactive IgG levels and affinity binding properties. Such changes of ghrelin-reactive IgG may underlie their decreased ghrelin-transporting capacities compromising ghrelin orexigenic and anxiolytic effects and contributing to chemotherapy-induced loss of appetite.

Cardiac cachexia: hic et nunc

Cardiac cachexia (CC) is the clinical entity at the end of the chronic natural course of heart failure (HF). Despite the efforts, even the most recent definition of cardiac cachexia has been challenged, more precisely, the addition of new criteria on top of obligatory weight loss. The pathophysiology of CC is complex and multifactorial. A better understanding of pathophysiological pathways in body wasting will contribute to establish potentially novel treatment strategies. The complex biochemical network related with CC and HF pathophysiology underlines that a single biomarker cannot reflect all of the features of the disease. Biomarkers that could pick up the changes in body composition before they convey into clinical manifestations of CC would be of great importance. The development of preventive and therapeutic strategies against cachexia, sarcopenia, and wasting disorders is perceived as an urgent need by healthcare professionals. The treatment of body wasting remains an unresolved challenge to this day. As CC is a multifactorial disorder, it is unlikely that any single agent will be completely effective in treating this condition. Among all investigated therapeutic strategies, aerobic exercise training in HF patients is the most proved to counteract skeletal muscle wasting and is recommended by treatment guidelines for HF.

Hypothalamic inflammation and food intake regulation during chronic illness

Anorexia is a common symptom in chronic illness. It contributes to malnutrition and strongly affects survival and quality of life. A common denominator of many chronic diseases is an elevated inflammatory status, which is considered to play a pivotal role in the failure of food-intake regulating systems in the hypothalamus. In this review, we summarize findings on the role of hypothalamic inflammation on food intake regulation involving hypothalamic neuropeptide Y (NPY) and pro-opiomelanocortin (POMC). Furthermore, we outline the role of serotonin in the inability of these peptide based food-intake regulating systems to respond and adapt to changes in energy metabolism during chronic disease.

Cardiac cachexia: hic et nunc: "hic et nunc" - here and now

Cardiac cachexia (CC) is the clinical entity at the end of chronic natural course of heart failure (HF). Despite the efforts, even the most recent definition of cardiac cachexia has been challenged, more precisely the addition of new criteria on top of obligatory weight loss. The pathophysiology of CC is complex and multifactorial. Better understanding of pathophysiological pathways in body wasting will contribute to establish potentially novel treatment strategies. The complex biochemical network related with CC and HF pathophysiology underlines that a single biomarker cannot reflect all of the features of the disease. Biomarkers that could pick-up the changes in body composition before they convey into clinical manifestations of CC would be of great importance. The development of preventive and therapeutic strategies against cachexia, sarcopenia and wasting disorders is perceived as an urgent need by healthcare professionals. The treatment of body wasting remains an unresolved challenge to this day. As CC is a multifactorial disorder, it is unlikely that any single agent will be completely effective in treating this condition. Among all investigated therapeutic strategies, aerobic exercise training in HF patients is the most proved to counteract skeletal muscle wasting and is recommended by treatment guidelines for HF.

A hypothesis for a possible synergy between ghrelin and exercise in patients with cachexia: Biochemical and physiological bases

This article reviews the biochemical and physiological observations underpinning the synergism between ghrelin and ghrelin agonists with exercise, especially progressive resistance training that has been shown to increase muscle mass. The synergy of ghrelin agonists and physical exercise could be beneficial in conditions where muscle wasting is present, such as that found in patients with advanced cancer. The principal mechanism that controls muscle anabolism following the activation of the ghrelin receptor in the central nervous system involves the release of growth hormone/insulin-like growth factor-1 (GH/IGF-1). GH/IGF-1 axis has a dual pathway of action on muscle growth: (a) a direct action on muscle, bone and fat tissue and (b) an indirect action via the production of both muscle-restricted mIGF-1 and anti-cachectic cytokines. Progressive resistance training is a potent inducer of the secretion the muscle-restricted IGF-1 (mIGF-1) that enhances protein synthesis, increases lean body mass and eventually leads to the improvement of muscle strength. Thus, the combination of ghrelin administration with progressive resistance training may serve to circumvent ghrelin resistance and further reduce muscle wasting, which are commonly associated with cachexia.

Anamorelin hydrochloride for the treatment of cancer-anorexia-cachexia in NSCLC

INTRODUCTION

Cancer anorexia-cachexia syndrome (CACS) is associated with increased morbidity and mortality. Anamorelin is a novel, orally active ghrelin receptor agonist in clinical development for the treatment of CACS in NSCLC. The aim of this review is to summarize preclinical and clinical studies evaluating anamorelin as a potential promising treatment for CACS in NSCLC.

AREAS COVERED

Pharmacodynamics, pharmacokinetics and metabolism, clinical efficacy, safety and tolerability of anamorelin for the treatment of CACS in NSCLC were reviewed. Anamorelin administration may lead to increases in food intake, body weight and lean body mass, and a stimulatory effect on growth hormone secretion in NSCLC patients. Anamorelin is well tolerated with no dose-limiting toxicities identified to date.

EXPERT OPINION

Targeting ghrelin receptors presents the advantage of potentially addressing multiple mechanisms of CACS simultaneously including appetite, muscle protein balance, adipose tissue metabolism, energy expenditure and inflammation. Clinical data suggest that anamorelin is well tolerated and it effectively increases appetite, body weight and lean mass in patients with advanced NSCLC. Long-term safety remains unknown at this time. The potential synergistic effects of anamorelin with nutritional support or exercise as well as its efficacy/safety in other tumor types are also unknown.

Comparison of Appetite-regulating Hormones and Body Composition in Pediatric Patients in Predialysis Stage of Chronic Kidney Disease and Healthy Control Group

BACKGROUND

Protein-energy malnutrition (PEM) is a common complication in pediatric patients with chronic kidney disease (CKD). Components incorporated in the regulation of appetite and body composition appear to be of the focus in renal insufficiency and may influence the CKD-associated PEM. The purpose of this study was to investigate plasma levels of appetite-regulating hormones and their correlation with the body composition variables in a pediatric in predialysis stage of CKD.

METHODS

Thirty children with CKD in predialysis stage were selected and compared with 30 healthy sex- and age-matched controls. Blood samples were collected in fasting. Serum total ghrelin, leptin, and obestatin levels were measured using enzyme immunometric assay methods. Anthropometric parameters measurement and body composition analysis were done using the bioelectric impedance analysis (BIA) method.

RESULTS

Patients showed insignificant elevated total ghrelin (105.40±30.83 ng/l), leptin (5.32±1.17 ng/ml) and obestatin (5.07±1.09 ng/ml) levels in comparison with healthy participants. By using BIA, patients had significantly different Dry Lean Weight (P=0.048), Extra Cellular Water (P=0.045), Body Cell Mass (BCM) (P=0.021), Basal Metabolic Rate (P=0.033) and Body Mass Index (P=0.029) compared with controls. Furthermore, the total body water was slightly and the ECW was significantly higher in CKD participants. There were significant negative correlation between obestatin and BCM (r=-0.40, P=0.03) and fat free mass index (FFMI) (r=-0.40, P=0.029) in patients.

CONCLUSION

It seems that our results are insufficient to clarify the role of appetite-regulating hormones in PEM in CKD patients. It is apparent that there are still many unknown parameters related to both appetite regulating and CKD-associated PEM.

Treatment of cachexia: an overview of recent developments

Body wasting in the context of chronic illness is associated with reduced quality of life and impaired survival. Recent clinical trials have investigated different approaches to improve patients' skeletal muscle mass and strength, exercise capacity, and survival in the context of cachexia and body wasting, many of them in patients with cancer. The aim of this article was to summarize clinical trials published over the past 2 years. Therapeutic approaches discussed include appetite stimulants, such as megestrol acetate, L-carnitine, or melatonin, anti-inflammatory drugs, such as thalidomide, pentoxyphylline, or a monoclonal antibody against interleukin-1α as well as ghrelin and the ghrelin agonist anamorelin; nutritional support, and anabolics, such as enobosarm and testosterone.

Muscle wasting: an overview of recent developments in basic research

The syndrome of cachexia, i.e., involuntary weight loss in patients with underlying diseases, sarcopenia, i.e., loss of muscle mass due to aging, and general muscle atrophy from disuse and/or prolonged bed rest have received more attention over the last decades. All lead to a higher morbidity and mortality in patients, and therefore, they represent a major socio-economic burden for the society today. This mini-review looks at recent developments in basic research that are relevant to the loss of skeletal muscle. It aims to cover the most significant publication of last 3 years on the causes and effects of muscle wasting, new targets for therapy development, and potential biomarkers for assessing skeletal muscle mass. The targets include the following: (1) E-3 ligases TRIM32, SOCS1, and SOCS3 by involving the elongin BC ubiquitin-ligase, Cbl-b, culling 7, Fbxo40, MG53 (TRIM72), and the mitochondrial Mul1; (2) the kinase MST1; and (3) the G-protein Gαi2. D(3)-creatine has the potential to be used as a novel biomarker that allows to monitor actual change in skeletal muscle mass over time. In conclusion, significant development efforts are being made by academic groups as well as numerous pharmaceutical companies to identify new target and biomarker muscles, as muscle wasting represents a great medical need, but no therapies have been approved in the last decades.

Muscle wasting: an overview of recent developments in basic research

The syndrome of cachexia, i.e. involuntary weight loss in patients with underlying diseases, sarcopenia, i.e. loss of muscle mass due to ageing, and general muscle atrophy from disuse and/or prolonged bed rest have received more attention over the last decades. All lead to a higher morbidity and mortality in patients and therefore, they represent a major socio-economic burden for the society today. This mini-review looks at recent developments in basic research that are relevant to the loss of skeletal muscle. It aims to cover the most significant publication of last three years on the causes and effects of muscle wasting, new targets for therapy development and potential biomarkers for assessing skeletal muscle mass. The targets include 1) E-3 ligases: TRIM32, SOCS1 and SOCS3 by involving the elongin BC ubiquitin-ligase, Cbl-b, culling 7, Fbxo40, MG53 (TRIM72) and the mitochondrial Mul1, 2) the kinase MST1 and 3) the G-protein Gαi2. D(3)-creatine has the potential to be used as a novel biomarker that allows to monitor actual change in skeletal muscle mass over time. In conclusion, significant development efforts are being made by academic groups as well as numerous pharmaceutical companies to identify new targets and biomarkers muscle, as muscle wasting represents a great medical need, but no therapies have been approved in the last decades.

Anorexia-cachexia syndrome in pancreatic cancer: recent advances and new pharmacological approach

About 80% of all pancreatic ductal adenocarcinoma patients suffer from a wasting syndrome referred to as the "cancer anorexia-cachexia syndrome" (CACS) characterized by abnormally low weight, weakness and loss of skeletal muscle mass with or without loss of body fat, which directly impacts overall survival, quality of life, and physical activity. The aim of this review was to examine recent findings about CACS' pathophysiology and to describe the current pharmacological approaches. In recent years many efforts were made to improve our knowledge of CACS; currently we know that cachexia arises from a complex and multifactorial interaction between various mechanisms including inflammation, anorexia/malnutrition, alterations of protein and lipid metabolism; consequently its management requires multidisciplinary and multipharmacological approach that should address the different causes underlying this clinical event. On these premises, several drugs have been proposed starting from the first pharmacological treatment based on progestational agents or corticosteroids; most of them are in the preclinical phase, but some have already reached the clinical experimentation stage. In conclusion, to date, there is no standard effective treatment and further studies are needed to unravel the basic mechanisms underlying CACS and to develop newer therapeutic strategies with the hope to improve the quality of life of pancreatic cancer patients.

Ghrelin inhibits doxorubicin cardiotoxicity by inhibiting excessive autophagy through AMPK and p38-MAPK

Doxorubicin (DOX) is a wide spectrum antitumor drug, but its clinical application is limited by the cardiotoxicity. Ghrelin, a multi-functional peptide hormone with metabolic regulation in energy homeostasis, plays important roles in cardiovascular protection. Now, the underlying mechanisms of ghrelin against DOX-induced cardiomyocyte apoptosis and atrophy are still not clear. In the present study, we revealed an autophagy-dependent mechanism involved in ghrelin's protection against DOX-induced cardiomyocyte death and size decrease. We observed that DOX insult induced remarkable mortality and cardiac dysfunction in mice, and increase in LDH leakage, cardiomyocyte apoptosis and decrease in cell viability and size in mouse hearts and H9c2 cell cultures, which were effectively improved by ghrelin supplement. We further observed that the strong autophagy stirred by DOX exposure was paralleling with the serious apoptosis and size decrease in cardiomyocytes. Ghrelin, like an autophagy inhibitor, 3-MA, inhibited the DOX-induced autophagy and attenuated cardiomyocyte apoptosis and size decrease. Furthermore, ghrelin significantly reduced the intercellular oxidative stress level, a strong autophagy trigger, partly by augmenting the expression and activities of the endogenous anti-oxidative enzymes. After the further investigation in the post signaling pathways of ghrelin receptors in H9c2 cells, including ERK, p38/MAPK, JNK, AMPK and Akt, we observed that ghrelin supplement only reduced the DOX-activated AMPK and augmented the DOX-down regulated p38-MAPK and mTOR phosphorylation. Our results indicated that ghrelin effectively improved the cardiomyocyte survival and size maintenance by suppressing the excessive autophagy through both ROS inhibition and mTOR induction through suppressing AMPK activity and stimulating p38-MAPK activity.

Growth hormone secretagogues exert differential effects on skeletal muscle calcium homeostasis in male rats depending on the peptidyl/nonpeptidyl structure

The orexigenic and anabolic effects induced by ghrelin and the synthetic GH secretagogues (GHSs) are thought to positively contribute to therapeutic approaches and the adjunct treatment of a number of diseases associated with muscle wasting such as cachexia and sarcopenia. However, many questions about the potential utility and safety of GHSs in both therapy and skeletal muscle function remain unanswered. By using fura-2 cytofluorimetric technique, we determined the acute effects of ghrelin, as well as of peptidyl and nonpeptidyl synthetic GHSs on calcium homeostasis, a critical biomarker of muscle function, in isolated tendon-to-tendon male rat skeletal muscle fibers. The synthetic nonpeptidyl GHSs, but not peptidyl ghrelin and hexarelin, were able to significantly increase resting cytosolic calcium [Ca²⁺]i. The nonpeptidyl GHS-induced [Ca²⁺]i increase was independent of GHS-receptor 1a but was antagonized by both thapsigargin/caffeine and cyclosporine A, indicating the involvement of the sarcoplasmic reticulum and mitochondria. Evaluation of the effects of a pseudopeptidyl GHS and a nonpeptidyl antagonist of the GHS-receptor 1a together with a drug-modeling study suggest the conclusion that the lipophilic nonpeptidyl structure of the tested compounds is the key chemical feature crucial for the GHS-induced calcium alterations in the skeletal muscle. Thus, synthetic GHSs can have different effects on skeletal muscle fibers depending on their molecular structures. The calcium homeostasis dysregulation specifically induced by the nonpeptidyl GHSs used in this study could potentially counteract the beneficial effects associated with these drugs in the treatment of muscle wasting of cachexia- or other age-related disorders.