Ghrelin prevents tumour- and cisplatin-induced muscle wasting: characterization of multiple mechanisms involved

Alteration of STIM1/Orai1-Mediated SOCE in Skeletal Muscle: Impact in Genetic Muscle Diseases and Beyond

Intracellular Ca2+ ions represent a signaling mediator that plays a critical role in regulating different muscular cellular processes. Ca2+ homeostasis preservation is essential for maintaining skeletal muscle structure and function. Store-operated Ca2+ entry (SOCE), a Ca2+-entry process activated by depletion of intracellular stores contributing to the regulation of various function in many cell types, is pivotal to ensure a proper Ca2+ homeostasis in muscle fibers. It is coordinated by STIM1, the main Ca2+ sensor located in the sarcoplasmic reticulum, and ORAI1 protein, a Ca2+-permeable channel located on transverse tubules. It is commonly accepted that Ca2+ entry via SOCE has the crucial role in short- and long-term muscle function, regulating and adapting many cellular processes including muscle contractility, postnatal development, myofiber phenotype and plasticity. Lack or mutations of STIM1 and/or Orai1 and the consequent SOCE alteration have been associated with serious consequences for muscle function. Importantly, evidence suggests that SOCE alteration can trigger a change of intracellular Ca2+ signaling in skeletal muscle, participating in the pathogenesis of different progressive muscle diseases such as tubular aggregate myopathy, muscular dystrophy, cachexia, and sarcopenia. This review provides a brief overview of the molecular mechanisms underlying STIM1/Orai1-dependent SOCE in skeletal muscle, focusing on how SOCE alteration could contribute to skeletal muscle wasting disorders and on how SOCE components could represent pharmacological targets with high therapeutic potential.

Growth hormone secretagogue receptor-1a mediates ghrelin's effects on attenuating tumour-induced loss of muscle strength but not muscle mass

BACKGROUND

Ghrelin may ameliorate cancer cachexia (CC) by preventing anorexia, muscle, and fat loss. However, the mechanisms mediating these effects are not fully understood. This study characterizes the pathways involved in muscle mass and strength loss in the Lewis lung carcinoma (LLC)-induced cachexia model, and the effects of ghrelin in mice with or without its only known receptor: the growth hormone secretagogue receptor-1a ((GHSR-1a), Ghsr+/+ and Ghsr-/- ).

METHODS

Five to 7-month-old male C57BL/6J Ghsr+/+ and Ghsr-/- mice were inoculated with 1 × 106 heat-killed (HK) or live LLC cells (tumour implantation, TI). When tumours were palpable (7 days after TI), tumour-bearing mice were injected with vehicle (T + V) or ghrelin twice/day for 14 days (T + G, 0.8 mg/kg), while HK-treated mice were given vehicle (HK + V). Body weight and grip strength were evaluated before TI and at termination (21 days after TI). Hindlimb muscles were collected for analysis.

RESULTS

Less pronounced body weight (BW) loss (87.70 ± 0.98% vs. 83.92 ± 1.23%, percentage of baseline BW in tumour-bearing Ghsr+/+ vs. Ghsr-/- , P = 0.008), and lower upregulation of ubiquitin-proteasome system (UPS, MuRF1/Trim63, 5.71 ± 1.53-fold vs. 9.22 ± 1.94-fold-change from Ghsr+/+ HK + V in tumour-bearing Ghsr+/+ vs. Ghsr-/- , P = 0.036) and autophagy markers (Becn1, Atg5, Atg7, tumour-bearing Ghsr+/+  < Ghsr-/- , all P < 0.02) were found in T + V Ghsr+/+ vs. Ghsr-/- mice. Ghrelin attenuated LLC-induced UPS marker upregulation in both genotypes, [Trim63 was decreased from 5.71 ± 1.53-fold to 1.96 ± 0.47-fold in Ghsr+/+ (T + V vs. T + G: P = 0.032) and 9.22 ± 1.94-fold to 4.72 ± 1.06-fold in Ghsr-/- (T + V vs. T + G: P = 0.008)]. Only in Ghsr+/+ mice ghrelin ameliorated LLC-induced grip strength loss [improved from 89.24 ± 3.48% to 97.80 ± 2.31% of baseline (T + V vs. T + G: P = 0.042)], mitophagy markers [Bnip3 was decreased from 2.28 ± 0.56 to 1.38 ± 0.14-fold (T + V vs. T + G: P ≤ 0.05)], and impaired mitochondrial respiration [State 3u improved from 698.23 ± 73.96 to 934.37 ± 95.21 pmol/min (T + V vs. T + G: P ≤ 0.05)], whereas these markers were not improved by ghrelin Ghsr-/- . Compared with Ghsr+/+ , Ghsr-/- tumour-bearing mice also showed decreased response to ghrelin in BW [T + G-treated Ghsr+/+ vs. Ghsr -/- : 91.75 ± 1.05% vs. 86.18 ± 1.13% of baseline BW, P < 0.001)], gastrocnemius (T + G-treated Ghsr+/+ vs. Ghsr-/- : 96.9 ± 2.08% vs. 88.15 ± 1.78% of Ghsr+/+ HK + V, P < 0.001) and quadriceps muscle mass (T + G-treated Ghsr+/+ vs. Ghsr-/- : 96.12 ± 2.31% vs. 88.36 ± 1.94% of Ghsr+/+ HK + V, P = 0.01), and gastrocnemius type IIA (T + G-treated Ghsr+/+ vs. Ghsr-/- : 1250.49 ± 31.72 vs. 1017.62 ± 70.99 μm2 , P = 0.027) and IIB fibre cross-sectional area (T + G-treated Ghsr+/+ vs. Ghsr-/- : 2496.48 ± 116.88 vs. 2183.04 ± 103.43 μm2 , P = 0.024).

CONCLUSIONS

Growth hormone secretagogue receptor-1a mediates ghrelin's effects on attenuating LLC-induced weakness but not muscle mass loss by modulating the autophagy-lysosome pathway, mitophagy, and mitochondrial respiration.

Chemotherapy-Induced Myopathy: The Dark Side of the Cachexia Sphere

Simple Summary

In addition to cancer-related factors, anti-cancer chemotherapy treatment can drive life-threatening body wasting in a syndrome known as cachexia. Emerging evidence has described the impact of several key chemotherapeutic agents on skeletal muscle in particular, and the mechanisms are gradually being unravelled. Despite this evidence, there remains very little research regarding therapeutic strategies to protect muscle during anti-cancer treatment and current global grand challenges focused on deciphering the cachexia conundrum fail to consider this aspect—chemotherapy-induced myopathy remains very much on the dark side of the cachexia sphere. This review explores the impact and mechanisms of, and current investigative strategies to protect against, chemotherapy-induced myopathy to illuminate this serious issue.

Abstract

Cancer cachexia is a debilitating multi-factorial wasting syndrome characterised by severe skeletal muscle wasting and dysfunction (i.e., myopathy). In the oncology setting, cachexia arises from synergistic insults from both cancer–host interactions and chemotherapy-related toxicity. The majority of studies have surrounded the cancer–host interaction side of cancer cachexia, often overlooking the capability of chemotherapy to induce cachectic myopathy. Accumulating evidence in experimental models of cachexia suggests that some chemotherapeutic agents rapidly induce cachectic myopathy, although the underlying mechanisms responsible vary between agents. Importantly, we highlight the capacity of specific chemotherapeutic agents to induce cachectic myopathy, as not all chemotherapies have been evaluated for cachexia-inducing properties—alone or in clinically compatible regimens. Furthermore, we discuss the experimental evidence surrounding therapeutic strategies that have been evaluated in chemotherapy-induced cachexia models, with particular focus on exercise interventions and adjuvant therapeutic candidates targeted at the mitochondria.

Amiloride ameliorates muscle wasting in cancer cachexia through inhibiting tumor-derived exosome release

Background

Cancer cachexia (CAC) reduces patient survival and quality of life. Developments of efficient therapeutic strategies are required for the CAC treatments. This long-term process could be shortened by the drug-repositioning approach which exploits old drugs approved for non-cachexia disease. Amiloride, a diuretic drug, is clinically used for treatments of hypertension and edema due to heart failure. Here, we explored the effects of the amiloride treatment for ameliorating muscle wasting in murine models of cancer cachexia.

Methods

The CT26 and LLC tumor cells were subcutaneously injected into mice to induce colon cancer cachexia and lung cancer cachexia, respectively. Amiloride was intraperitoneally injected daily once tumors were formed. Cachexia features of the CT26 model and the LLC model were separately characterized by phenotypic, histopathologic and biochemical analyses. Plasma exosomes and muscle atrophy-related proteins were quantitatively analyzed. Integrative NMR-based metabolomic and transcriptomic analyses were conducted to identify significantly altered metabolic pathways and distinctly changed metabolism-related biological processes in gastrocnemius.

Results

The CT26 and LLC cachexia models displayed prominent cachexia features including decreases in body weight, skeletal muscle, adipose tissue, and muscle strength. The amiloride treatment in tumor-bearing mice distinctly alleviated muscle atrophy and relieved cachexia-related features without affecting tumor growth. Both the CT26 and LLC cachexia mice showed increased plasma exosome densities which were largely derived from tumors. Significantly, the amiloride treatment inhibited tumor-derived exosome release, which did not obviously affect exosome secretion from non-neoplastic tissues or induce observable systemic toxicities in normal healthy mice. Integrative-omics revealed significant metabolic impairments in cachectic gastrocnemius, including promoted muscular catabolism, inhibited muscular protein synthesis, blocked glycolysis, and impeded ketone body oxidation. The amiloride treatment evidently improved the metabolic impairments in cachectic gastrocnemius.

Conclusions

Amiloride ameliorates cachectic muscle wasting and alleviates cancer cachexia progression through inhibiting tumor-derived exosome release. Our results are beneficial to understanding the underlying molecular mechanisms, shedding light on the potentials of amiloride in cachexia therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13395-021-00274-5.

Receptor-Mediated Muscle Homeostasis as a Target for Sarcopenia Therapeutics

Sarcopenia is a disease characterized by age-related decline of skeletal muscle mass and function. The molecular mechanisms of the pathophysiology of sarcopenia form a complex network due to the involvement of multiple interconnected signaling pathways. Therefore, signaling receptors are major targets in pharmacological strategies in general. To provide a rationale for pharmacological interventions for sarcopenia, we herein describe several druggable signaling receptors based on their role in skeletal muscle homeostasis and changes in their activity with aging. A brief overview is presented of the efficacy of corresponding drug candidates under clinical trials. Strategies targeting the androgen receptor, vitamin D receptor, Insulin-like growth factor-1 receptor, and ghrelin receptor primarily focus on promoting anabolic action using natural ligands or mimetics. Strategies involving activin receptors and angiotensin receptors focus on inhibiting catabolic action. This review may help to select specific targets or combinations of targets in the future.

Quality by Design Approach for the Development of Liposome Carrying Ghrelin for Intranasal Administration

The therapeutic use of peptides has increasingly recognized in the development of new therapies. However, the susceptible enzymatic cleavage is a barrier that needs to overcome. Nose-to-brain delivery associated with liposomes can protect peptides against biodegradation and improve the accessibility to brain targets. The aim was to develop a liposomal formulation as ghrelin carrier. The quality by design (QbD) approach was used as a strategy for method development. The initial risk assessments were carried out using a fishbone diagram. A screening design study was performed for the critical material attributes/critical process parameters (CMAs/CPPs) on critical quality attributes (CQAs). Liposomes were obtained by hydrating phospholipid films, followed by extrusion or homogenization, and coated with chitosan. The optimized liposome formulation was produced by high-pressure homogenization coated with chitosan, and the resulted were liposomes size 72.25 ± 1.46 nm, PDI of 0.300 ± 0.027, the zeta potential of 50.3 ± 1.46 mV, and encapsulation efficiency of 53.2%. Moreover, chitosan coating improved performance in ex vivo permeation and mucoadhesion analyzes when compared to the uncoated liposome. In this context, chitosan coating is essential for the performance of the formulations in the ex vivo permeation and mucoadhesion analyzes. The intranasal administration of ghrelin liposomes coated with chitosan offers an innovative opportunity to treat cachexia.

Understanding the biology of volumetric muscle loss for an individualized exercise rehabilitation approach in breast cancer patients

Muscle maintenance relies on a multidimensional biologic balance that is extremely delicate in breast cancer patients, particularly those with advanced-stage disease. The biology that underpins breast cancer tumorigenesis, tumor progression and response to pharmacotherapies can modify muscle homeostasis, resulting in volumetric muscle loss. This condition dramatically increases the overall patients' frailty, leading to reduced survival and impaired quality of life. Physical activity may potentially improve muscle health in these patients, providing that an optimal patients selection is performed. The understanding of volumetric muscle loss biology in breast cancer survivors, coupled with focused clinical studies, would allow for the implementation of individualized rehabilitation protocols.

Phenotypic features of cancer cachexia-related loss of skeletal muscle mass and function: lessons from human and animal studies

Cancer cachexia is a complex multi-organ catabolic syndrome that reduces mobility, increases fatigue, decreases the efficiency of therapeutic strategies, diminishes the quality of life, and increases the mortality of cancer patients. This review provides an exhaustive and comprehensive analysis of cancer cachexia-related phenotypic changes in skeletal muscle at both the cellular and subcellular levels in human cancer patients, as well as in animal models of cancer cachexia. Cancer cachexia is characterized by a major decrease in skeletal muscle mass in human and animals that depends on the severity of the disease/model and the localization of the tumour. It affects both type 1 and type 2 muscle fibres, even if some animal studies suggest that type 2 muscle fibres would be more prone to atrophy. Animal studies indicate an impairment in mitochondrial oxidative metabolism resulting from a decrease in mitochondrial content, an alteration in mitochondria morphology, and a reduction in mitochondrial metabolic fluxes. Immuno-histological analyses in human and animal models also suggest that a faulty mechanism of skeletal muscle repair would contribute to muscle mass loss. An increase in collagen deposit, an accumulation of fat depot outside and inside the muscle fibre, and a disrupted contractile machinery structure are also phenotypic features that have been consistently reported in cachectic skeletal muscle. Muscle function is also profoundly altered during cancer cachexia with a strong reduction in skeletal muscle force. Even though the loss of skeletal muscle mass largely contributes to the loss of muscle function, other factors such as muscle-nerve interaction and calcium handling are probably involved in the decrease in muscle force. Longitudinal analyses of skeletal muscle mass by imaging technics and skeletal muscle force in cancer patients, but also in animal models of cancer cachexia, are necessary to determine the respective kinetics and functional involvements of these factors. Our analysis also emphasizes that measuring skeletal muscle force through standardized tests could provide a simple and robust mean to early diagnose cachexia in cancer patients. That would be of great benefit to cancer patient's quality of life and health care systems.

Translational research on Myology and Mobility Medicine: 2021 semi-virtual PDM3 from Thermae of Euganean Hills, May 26 - 29, 2021

On 19-21 November 2020, the meeting of the 30 years of the Padova Muscle Days was virtually held while the SARS-CoV-2 epidemic was hitting the world after a seemingly quiet summer. During the 2020-2021 winter, the epidemic is still active, despite the start of vaccinations. The organizers hope to hold the 2021 Padua Days on Myology and Mobility Medicine in a semi-virtual form (2021 S-V PDM3) from May 26 to May 29 at the Thermae of Euganean Hills, Padova, Italy. Here the program and the Collection of Abstracts are presented. Despite numerous world problems, the number of submitted/selected presentations (lectures and oral presentations) has increased, prompting the organizers to extend the program to four dense days.

A Pound of Flesh: What Cachexia Is and What It Is Not

Body weight loss, mostly due to the wasting of skeletal muscle and adipose tissue, is the hallmark of the so-called cachexia syndrome. Cachexia is associated with several acute and chronic disease states such as cancer, chronic obstructive pulmonary disease (COPD), heart and kidney failure, and acquired and autoimmune diseases and also pharmacological treatments such as chemotherapy. The clinical relevance of cachexia and its impact on patients’ quality of life has been neglected for decades. Only recently did the international community agree upon a definition of the term cachexia, and we are still awaiting the standardization of markers and tests for the diagnosis and staging of cancer-related cachexia. In this review, we discuss cachexia, considering the evolving use of the term for diagnostic purposes and the implications it has for clinical biomarkers, to provide a comprehensive overview of its biology and clinical management. Advances and tools developed so far for the in vitro testing of cachexia and drug screening will be described. We will also evaluate the nomenclature of different forms of muscle wasting and degeneration and discuss features that distinguish cachexia from other forms of muscle wasting in the context of different conditions.

GDF-15 Neutralization Alleviates Platinum-Based Chemotherapy-Induced Emesis, Anorexia, and Weight Loss in Mice and Nonhuman Primates

Platinum-based cancer therapy is restricted by dose-limiting side effects and is associated with elevation of growth differentiation factor 15 (GDF-15). But whether this elevation contributes to such side effects has been unclear. Here, we explored the effects of GDF-15 blockade on platinum-based chemotherapy-induced emesis, anorexia, and weight loss in mice and/or nonhuman primate models. We found that circulating GDF-15 is higher in subjects with cancer receiving platinum-based chemotherapy and is positively associated with weight loss in colorectal cancer (NCT00609622). Further, chemotherapy agents associated with high clinical emetic score induce circulating GDF-15 and weight loss in mice. Platinum-based treatment-induced anorexia and weight loss are attenuated in GDF-15 knockout mice, while GDF-15 neutralization with the monoclonal antibody mAB1 improves survival. In nonhuman primates, mAB1 treatment attenuates anorexia and emesis. These results suggest that GDF-15 neutralization is a potential therapeutic approach to alleviate chemotherapy-induced side effects and improve the quality of life.

Linalool Prevents Cisplatin Induced Muscle Atrophy by Regulating IGF-1/Akt/FoxO Pathway

Skeletal muscle atrophy is an important feature of cancer cachexia, which can be induced by chemotherapy, and affects the survival and quality of life of cancer patients seriously. No specific drugs for cancer cachexia have been applied in clinical practice. This study explored the therapeutic effect of linalool (LIN) on cisplatin (DDP) induced skeletal muscle atrophy. In vivo, LIN can improve skeletal muscle weight loss, anorexia, muscle strength decline and other cachexia symptoms caused by cisplatin treatment in a Lewis lung cancer tumor bearing mouse model, and cause no adverse effects on the anti-tumour effect. LIN treatment decreased the expression of muscle RING-finger protein-1 (MuRF1) and Atrogin1(MAFbx) in muscle, and the activation of insulin-like growth factor-1 (IGF-1)/protein kinase B (Akt)/forkhead box O (FoxO) pathway was observed. In vitro, LIN alleviated DDP induced C2C12 myotube atrophy, and IGF-1 receptor inhibitor Picropodophyllin (PIC), which had no adverse effect on C2C12 myotube cells, could reverse the protective effect of LIN. These results indicate that LIN down-regulates the expression of Atrogin1 and MuRF1 through the IGF-1/Akt/FoxO pathway, alleviating DDP-induced muscle atrophy and improving cachexia symptoms. LIN has the potential to be developed as a drug against cancer cachexia.

Acylated and unacylated ghrelin relieve cancer cachexia in mice through multiple mechanisms

Cancer cachexia is a wasting syndrome resulting from decreased protein synthesis and increased protein degradation. Calpain-dependent cleavage of myofilament is the initial step of myofilament degradation and plays a critical role in muscle atrophy. Ghrelin is a multifunctional hormone known to improve protein synthesis and inhibit protein degradation. However, its mechanism of action is not fully understood. Here we investigated whether acylated ghrelin (AG) and unacylated ghrelin (UnAG) could protect against cancer cachexia in mice bearing CT26 colorectal adenocarcinoma. We found for the first time that both AG and UnAG could inhibit calpain activity in skeletal muscle of cancer cachectic mice. AG and UnAG also improved tumor-free body weight, grip strength, muscle mass, epididymal fat mass, and nutritional state in tumor-bearing (TB) mice. Moreover, AG and UnAG reduced serum tumor necrosis factor-± concentration, increased Akt activity, and downregulated atrogin-1 expression in TB mice. Our results may contribute to the development of an AG/UnAG-based therapy for cancer cachexia.

Noninvasive, longitudinal imaging-based analysis of body adipose tissue and water composition in a melanoma mouse model and in immune checkpoint inhibitor-treated metastatic melanoma patients

Background

As cancer cachexia (CC) is associated with cancer progression, early identification would be beneficial. The aim of this study was to establish a workflow for automated MRI-based segmentation of visceral (VAT) and subcutaneous adipose tissue (SCAT) and lean tissue water (LTW) in a B16 melanoma animal model, monitor diseases progression and transfer the protocol to human melanoma patients for therapy assessment.

Methods

For in vivo monitoring of CC B16 melanoma-bearing and healthy mice underwent longitudinal three-point DIXON MRI (days 3, 12, 17 after subcutaneous tumor inoculation). In a prospective clinical study, 18 metastatic melanoma patients underwent MRI before, 2 and 12 weeks after onset of checkpoint inhibitor therapy (CIT; n = 16). We employed an in-house MATLAB script for automated whole-body segmentation for detection of VAT, SCAT and LTW.

Results

B16 mice exhibited a CC phenotype and developed a reduced VAT volume compared to baseline (B16 − 249.8 µl, − 25%; controls + 85.3 µl, + 10%, p = 0.003) and to healthy controls. LTW was increased in controls compared to melanoma mice. Five melanoma patients responded to CIT, 7 progressed, and 6 displayed a mixed response. Responding patients exhibited a very limited variability in VAT and SCAT in contrast to others. Interestingly, the LTW was decreased in CIT responding patients (− 3.02% ± 2.67%; p = 0.0034) but increased in patients with progressive disease (+ 1.97% ± 2.19%) and mixed response (+ 4.59% ± 3.71%).

Conclusion

MRI-based segmentation of fat and water contents adds essential additional information for monitoring the development of CC in mice and metastatic melanoma patients during CIT or other treatment approaches.

The Etiology and Impact of Muscle Wasting in Metastatic Cancer

Metastasis arises when cancer cells disseminate from their site of origin and invade distant organs. While cancer cells rarely colonize muscle, they often induce a debilitating muscle-wasting condition known as cachexia that compromises feeding, breathing, and cardiac function in metastatic cancer patients. In fact, nearly 80% of metastatic cancer patients experience a spectrum of muscle-wasting states, which deteriorates the quality of life and overall survival of cancer patients. Muscle wasting in cancer results from increased muscle catabolism induced by circulating tumor factors and a systemic metabolic dysfunction. In addition, muscle loss can be exacerbated by the exposure to antineoplastic therapies and the process of aging. With no approved therapies to alleviate cachexia, muscle health, therefore, becomes a key determinant of prognosis, treatment response, and survival in metastatic cancer patients. This review will discuss the current understanding of cancer-associated cachexia and highlight promising therapeutic strategies to treat muscle wasting in the context of metastatic cancers.

Ghrelin ameliorates tumor-induced adipose tissue atrophy and inflammation via Ghrelin receptor-dependent and -independent pathways

Adipose tissue (AT) atrophy is a hallmark of cancer cachexia contributing to increased morbidity/mortality. Ghrelin has been proposed as a treatment for cancer cachexia partly by preventing AT atrophy. However, the mechanisms mediating ghrelin's effects are incompletely understood, including the extent to which its only known receptor, GHSR-1a, is required for these effects. This study characterizes the pathways involved in AT atrophy in the Lewis Lung Carcinoma (LLC)-induced cachexia model and those mediating the effects of ghrelin in Ghsr ^+/+ and Ghsr ^-/- mice. We show that LLC causes AT atrophy by inducing anorexia, and increasing lipolysis, AT inflammation, thermogenesis and energy expenditure. These changes were greater in Ghsr ^-/-. Ghrelin administration prevented LLC-induced anorexia only in Ghsr ^+/+, but prevented WAT lipolysis, inflammation and atrophy in both genotypes, although its effects were greater in Ghsr ^+/+. LLC-induced increases in BAT inflammation, WAT and BAT thermogenesis, and energy expenditure were not affected by ghrelin. In conclusion, ghrelin ameliorates WAT inflammation, fat atrophy and anorexia in LLC-induced cachexia. GHSR-1a is required for ghrelin's orexigenic effect but not for its anti-inflammatory or fat-sparing effects.

Mazzola P, Souto EB, Chaud MV. Cachexia: Pathophysiology and Ghrelin Liposomes for Nose-to-Brain Delivery

Cachexia, a severe multifactorial condition that is underestimated and unrecognized in patients, is characterized by continuous muscle mass loss that leads to progressive functional impairment, while nutritional support cannot completely reverse this clinical condition. There is a strong need for more effective and targeted therapies for cachexia patients. There is a need for drugs that act on cachexia as a distinct and treatable condition to prevent or reverse excess catabolism and inflammation. Due to ghrelin properties, it has been studied in the cachexia and other treatments in a growing number of works. However, in the body, exogenous ghrelin is subject to very rapid degradation. In this context, the intranasal release of ghrelin-loaded liposomes to cross the blood-brain barrier and the release of the drug into the central nervous system may be a promising alternative to improve its bioavailability. The administration of nose-to-brain liposomes for the management of cachexia was addressed only in a limited number of published works. This review focuses on the discussion of the pathophysiology of cachexia, synthesis and physiological effects of ghrelin and the potential treatment of the diseased using ghrelin-loaded liposomes through the nose-to-brain route.

Both ghrelin deletion and unacylated ghrelin overexpression preserve muscles in aging mice

Sarcopenia, the decline in muscle mass and functionality during aging, might arise from age-associated endocrine dysfunction. Ghrelin is a hormone circulating in both acylated (AG) and unacylated (UnAG) forms with anti-atrophic activity on skeletal muscle. Here, we show that not only lifelong overexpression of UnAG (Tg) in mice, but also the deletion of ghrelin gene (Ghrl KO) attenuated the age-associated muscle atrophy and functionality decline, as well as systemic inflammation. Yet, the aging of Tg and Ghrl KO mice occurs with different dynamics: while old Tg mice seem to preserve the characteristics of young animals, Ghrl KO mice features deteriorate with aging. However, young Ghrl KO mice show more favorable traits compared to WT animals that result, on the whole, in better performances in aged Ghrl KO animals. Treatment with pharmacological doses of UnAG improved muscle performance in old mice without modifying the feeding behavior, body weight, and adipose tissue mass. The antiatrophic effect on muscle mass did not correlate with modifications of protein catabolism. However, UnAG treatment induced a strong shift towards oxidative metabolism in muscle. Altogether, these data confirmed and expanded some of the previously reported findings and advocate for the design of UnAG analogs to treat sarcopenia.

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.

Increased tumour burden alters skeletal muscle properties in the KPC mouse model of pancreatic cancer

BACKGROUND

Cancer cachexia is a multifactorial wasting syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. We address these issues in a novel transgenic mouse model Kras, Trp53 and Pdx-1-Cre (KPC) of pancreatic ductal adenocarcinoma (PDA) using multi-parametric magnetic resonance (mp-MR) measures.

METHODS

KPC mice (n = 10) were divided equally into two groups (n = 5/group) depending on the size of the tumor i.e. tumor size <250 mm³ and >250 mm³. Using mp-MR measures, we demonstrated the changes in the gastrocnemius muscle at the microstructural level. In addition, we evaluated skeletal muscle contractile function in KPC mice using an in vivo approach.

RESULTS

Increase in tumor size resulted in decrease in gastrocnemius maximum cross sectional area, decrease in T₂ relaxation time, increase in magnetization transfer ratio, decrease in mean diffusivity, and decrease in radial diffusivity of water across the muscle fibers. Finally, we detected significant decrease in absolute and specific force production of gastrocnemius muscle with increase in tumor size.

CONCLUSIONS

Our findings indicate that increase in tumor size may cause alterations in structural and functional parameters of skeletal muscles and that MR parameters may be used as sensitive biomarkers to noninvasively detect structural changes in cachectic muscles.

D-methionine improves cisplatin-induced anorexia and dyspepsia syndrome by attenuating intestinal tryptophan hydroxylase 1 activity and increasing plasma leptin concentration

BACKGROUND

Cisplatin is a widely used antineoplastic drug. However, cisplatin-induced dyspepsia syndromes, including delayed gastric emptying, gastric distension, early satiety, nausea, and vomiting, often force patients to take doses lower than those prescribed or even refuse treatment. D-methionine has an appetite-enhancing effect and alleviates weight loss during cisplatin treatment.

METHODS

This work established a model of anorexia and dyspepsia symptoms with intraperitoneal injection of cisplatin (5 mg/kg) once a week for three cycles. Presupplementation with or without D-methionine (300 mg/kg) was performed. Orexigenic and anorexigenic hormones (ghrelin, leptin, and glucagon-like peptide-1), tryptophan hydroxylase 1 (TPH1), 5-hydroxytryptamine receptors (5-HT_2C and 5-HT₃ ), and hypothalamic feeding-related peptides were measured by immunohistochemistry staining, enzyme-linked immunosorbent assay, and real-time PCR assay.

KEY RESULTS

Cisplatin administration caused marked decrease in appetite and body weight, promoted adipose and fat tissue atrophy, and delayed gastric emptying and gastric distension, and D-methionine preadministration prior to cisplatin administration significantly ameliorated these side effects. Besides, cisplatin induced an evident increase in serum ghrelin level, TPH1 activity, and 5-HT₃ receptor expression in the intestine and decreased plasma leptin levels and gastric ghrelin mRNA gene expression levels. D-methionine supplementation recovered these changes. The expression of orexigenic neuropeptide Y/agouti-related peptide and anorexigenic cocaine- and amphetamine-regulated transcript proopiomelanocortin neurons were altered by D-methionine supplementation in cisplatin-induced anorexia rats.

CONCLUSIONS AND INFERENCES

D-methionine supplementation prevents cisplatin-induced anorexia and dyspepsia syndrome possibly by attenuating intestinal tryptophan hydroxylase 1 activity and increasing plasma leptin concentration. Therefore, D-methionine can be used as an adjuvant therapy for treating cisplatin-induced adverse effects.

Ghrelin ameliorates chronic obstructive pulmonary disease-associated infllammation and autophagy

Chronic obstructive pulmonary disease (COPD) is a chronic and devastating condition characterized by poor airflow and breath. Smoking and other environmental factors-caused inflammations triggered excessive autophagy of normal lung epithelial cells, eventually leading to impaired lung functions. Previous studies showed that ghrelin exhibited beneficial effects on patients with COPD. However, the mechanisms underlying this impact remained largely unknown. In this study, in vitro and in vivo models of COPD-associated inflammation were established, and we found that inflammation and autophagy were abonormally activated through nuclear factor kappa b (NF-κB) and activator protein-1 (AP-1) signaling pathways. Interestingly, ghrelin could inhibit the excessive inflammation pathways and autophagy induced by particle matter and/or cigarette extract in bronchial epithelial cells. Furthermore, NF-κB and AP-1 signaling were both inhibited while lung functions were significantly improved. Taken together, identification of downstream signaling of ghrelin in inflammation provided a new avenue in the treatment of COPD.

The Role of Malnutrition and Muscle Wasting in Advanced Lung Cancer

PURPOSE OF REVIEW

Malnutrition, cancer cachexia, and sarcopenia often co-occur in patients with advanced cancer and are associated with poorer response to chemotherapy and reduced survival. Here, we evaluate the current literature regarding the role of nutrition and these associated conditions in patients with advanced lung cancer.

RECENT FINDINGS

While rates of malnutrition are high, nutritional intervention studies have generally been limited by small sample sizes. Novel strategies such as home-based meal delivery may have promise. While no therapy is approved for cancer cachexia, ghrelin agonists and other targeted therapies have yielded promising data in clinical trials. Recent data also suggest that obesity may improve immunotherapy responsiveness. Malnutrition and associated muscle wasting are clearly negative prognostic markers in advanced lung cancer. Patients with malnutrition should be urgently referred for dietary counseling and guidelines for nutritional support should be followed. Optimal treatment of these syndromes will likely include nutrition and anti-cachexia interventions used in combination.

Advances in cancer cachexia: Intersection between affected organs, mediators, and pharmacological interventions

Advanced cancer patients exhibit cachexia, a condition characterized by a significant reduction in the body weight predominantly from loss of skeletal muscle and adipose tissue. Cachexia is one of the major causes of morbidity and mortality in cancer patients. Decreased food intake and multi-organ energy imbalance in cancer patients worsen the cachexia syndrome. Cachectic cancer patients have a low tolerance for chemo- and radiation therapies and also have a reduced quality of life. The presence of tumors and the current treatment options for cancer further exacerbate the cachexia condition, which remains an unmet medical need. The onset of cachexia involves crosstalk between different organs leading to muscle wasting. Recent advancements in understanding the molecular mechanisms of skeletal muscle atrophy/hypertrophy and adipose tissue wasting/browning provide a platform for the development of new targeted therapies. Therefore, a better understanding of this multifactorial disorder will help to improve the quality of life of cachectic patients. In this review, we summarize the metabolic mediators of cachexia, their molecular functions, affected organs especially with respect to muscle atrophy and adipose browning and then discuss advanced therapeutic approaches to cancer cachexia.

Cisplatin-Induced Skeletal Muscle Dysfunction: Mechanisms and Counteracting Therapeutic Strategies

Among the severe side effects induced by cisplatin chemotherapy, muscle wasting is the most relevant one. This effect is a major cause for a clinical decline of cancer patients, since it is a negative predictor of treatment outcome and associated to increased mortality. However, despite its toxicity even at low doses, cisplatin remains the first-line therapy for several types of solid tumors. Thus, effective pharmacological treatments counteracting or minimizing cisplatin-induced muscle wasting are urgently needed. The dissection of the molecular pathways responsible for cisplatin-induced muscle dysfunction gives the possibility to identify novel promising therapeutic targets. In this context, the use of animal model of cisplatin-induced cachexia is very useful. Here, we report an update of the most relevant researches on the mechanisms underlying cisplatin-induced muscle wasting and on the most promising potential therapeutic options to preserve muscle mass and function.

Overcoming resistance to anabolic SARM therapy in experimental cancer cachexia with an HDAC inhibitor

No approved therapy exists for cancer-associated cachexia. The colon-26 mouse model of cancer cachexia mimics recent late-stage clinical failures of anabolic anti-cachexia therapy and was unresponsive to anabolic doses of diverse androgens, including the selective androgen receptor modulator (SARM) GTx-024. The histone deacetylase inhibitor (HDACi) AR-42 exhibited anti-cachectic activity in this model. We explored combined SARM/AR-42 therapy as an improved anti-cachectic treatment paradigm. A reduced dose of AR-42 provided limited anti-cachectic benefits, but, in combination with GTx-024, significantly improved body weight, hindlimb muscle mass, and grip strength versus controls. AR-42 suppressed the IL-6/GP130/STAT3 signaling axis in muscle without impacting circulating cytokines. GTx-024-mediated β-catenin target gene regulation was apparent in cachectic mice only when combined with AR-42. Our data suggest cachectic signaling in this model involves catabolic signaling insensitive to anabolic GTx-024 therapy and a blockade of GTx-024-mediated anabolic signaling. AR-42 mitigates catabolic gene activation and restores anabolic responsiveness to GTx-024. Combining GTx-024, a clinically established anabolic therapy, with AR-42, a clinically evaluated HDACi, represents a promising approach to improve anabolic response in cachectic patients.

Chemotherapy-Induced Sarcopenia

OPINION STATEMENT

Sarcopenia is being consistently recognized as a condition not only associated with the presence of a malignancy but also induced by the oncologic therapies. Due to its negative impact on tolerance to chemotherapy and final outcome in both medical and surgical cancer patients, sarcopenia should be always considered and prevented, and, if recognized, should be appropriately treated. A CT scan at the level of the third lumbar vertebra, using an appropriate software, is the more common and easily available way to diagnose sarcopenia. It is now acknowledged that mechanisms involved in iatrogenic sarcopenia are several and depending on the type of molecule included in the regimen of chemotherapy, different pharmacologic antidotes will be required in the future. However, progression of the disease and the associated malnutrition per se are able to progressively erode the muscle mass and since sarcopenia is the hallmark of cachexia, the therapeutic approach to chemotherapy-induced sarcopenia parallels that of cachexia. This approach mainly relies on those strategies which are able to increase the lean body mass and include the use of anabolic/anti-inflammatory agents, nutritional interventions, physical exercise and, even better, a combination of different therapies. There are some phase II studies and some small controlled randomized trials which have validated these treatments using single agents or combined multimodal approaches. While these approaches may require the cooperation of some specialists (nutritionists with a specific knowledge on pathophysiology of catabolic states, accredited exercise physiologists and physiotherapists), the oncologist too should directly enter these issues to coordinate the choice and priority of the treatments. Who better than the oncologist knows the natural history of the disease, its evolution, and the probability of tolerance and response to the oncologic therapy? Only the oncologist knows when it is essential to potentiate any effort to better achieve a control of the disease, using all the available armamentarium, and when the condition is too advanced and hence requires a more palliative than supporting care. The oncologist also knows when to expect a gastrointestinal toxicity (mucositis, nausea, vomiting, and diarrhea) and hence it is more convenient using a parenteral than an enteral nutritional intervention or, on the contrary, when patient is suitable for discharge from hospital and oral supplements should be promptly tested for compliance and then prescribed. When patients are at high risk for malnutrition or if, regardless of their nutritional status, they are candidate to aggressive and potentially toxic treatments, they should undergo a jointed evaluation by the oncologist and the nutritionist and physical therapist to assess together a combined approach. In conclusion, the treatment of both cancer- or chemotherapy-related sarcopenia represents a challenge for the modern oncologist who must be able to coordinate a new panel of specialists with the same skill necessary to decide the priority of different oncologic treatments within a complex multidisciplinary context.

Inactivity and Skeletal Muscle Metabolism: A Vicious Cycle in Old Age

Aging is an inevitable and gradually progressive process affecting all organs and systems. The musculoskeletal system makes no exception, elderly exhibit an increased risk of sarcopenia (low muscle mass),dynapenia (declining muscle strength), and subsequent disability. Whereas in recent years the subject of skeletal muscle metabolic decline in the elderly has been gathering interest amongst researchers, as well as medical professionals, there are many challenges yet to be solved in order to counteract the effects of aging on muscle function efficiently. Noteworthy, it has been shown that aging individuals exhibit a decline in skeletal muscle metabolism, a phenomenon which may be linked to a number of predisposing (risk) factors such as telomere attrition, epigenetic changes, mitochondrial dysfunction, sedentary behavior (leading to body composition alterations), age-related low-grade systemic inflammation (inflammaging), hormonal imbalance, as well as a hypoproteic diet (unable to counterbalance the repercussions of the age-related increase in skeletal muscle catabolism). The present review aims to discuss the relationship between old age and muscle wasting in an effort to highlight the modifications in skeletal muscle metabolism associated with aging and physical activity.

D-Methionine Ameliorates Cisplatin-Induced Muscle Atrophy via Inhibition of Muscle Degradation Pathway

Cisplatin induces anorexia, weight loss, loss of adipose tissue, skeletal muscle atrophy, and serious adverse effects that can cause premature termination of chemotherapy. The aim of this study was to use an animal model to assess cisplatin therapy (3 cycles) with and without d-methionine to investigate its protective effects on cisplatin-induced anorexia and skeletal muscle wasting. Wistar rats were divided into 3 groups and treated as follows: saline as control (group 1), intraperitoneal cisplatin once a week for 3 weeks (group 2), and intraperitoneal cisplatin once a week for 3 weeks plus oral administration of d-methionine (group 3). Tissue somatic index (TSI), gastric emptying index (GEI), and feeding efficiency were measured. Both hepatic lipid metabolism and muscle atrophy-related gene expressions and C2C12 myotubes were determined by polymerase chain reaction. Micro-computed tomography (micro-CT) was used to conduct assessment of bone microarchitecture indices. Pathological changes of the gastric mucosa were assessed by hematoxylin and eosin staining after euthanizing the animals. d-Methionine increased food intake, weight gain, gastric emptying, and feeding efficiency, as well as decrease stomach contents, after cisplatin injections. Cisplatin caused shortening of myofibers. Cisplatin-induced muscle mass wasting was mediated by the elevation of mRNA expressions of MAFbx and MuRF-1 in ubiquitin ligases in muscle tissue homogenate. The mRNA expressions of MyoD and myogenin, markers of muscle differentiation, declined following cisplatin administration. The administration of d-methionine not only led to significant improvements in myofiber diameter and cross-sectional fiber areas but also reversed muscle atrophy-related gene expression. However, there were no significant changes in stomach histology or microarchitecture of trabecular bone among the study groups. The results indicate that d-methionine has an appetite-enhancing effect and ameliorates cisplatin-induced adipose and muscle tissue loss during cisplatin-based chemotherapy.

The concurrent treatment of Scutellaria baicalensis Georgi enhances the therapeutic efficacy of cisplatin but also attenuates chemotherapy-induced cachexia and acute kidney injury

ETHNOPHARMACOLOGICAL RELEVANCE

Cisplatin is an important chemotherapy to lung cancer, but it usually induces severe cachexia and acute kidney injury in patients. Scutellaria baicalensis Georgi (SB), commonly known as a skullcap, is a popular Chinese herbal medicine mainly used to treat inflammation, infection, and malignancy. In this study, we report the synergic effect of SB and cisplatin to Lewis lung carcinoma (LLC) cells, and the ameliorative effect of SB to cisplatin-induced cachexia and acute kidney injury.

MATERIALS AND METHODS

The extract of SB was applied by water boiling and lyophilization. The MTS assay was used to exam the in-vitro effects of SB and cisplatin on the LLC viability. In the animal experiment, male C57BL/6J mice were inoculated with LLC cells, and then treated by cisplatin intraperitoneally and the SB extract orally. Tumor volume, weights of tumor, murine body, white adipose tissue and gastrocnemius muscle, as well as serum levels of BUN and creatinine were measured during the experiment. Murine kidney sample was observed after the H&E and annexin V staining.

RESULTS

SB provided an enhancement of cisplatin action to inhibit tumor growth in vitro and in vivo. In the animal experiment, SB improved the loss of murine body weight and gastrocnemius muscle, the elevating BUN level, and the apoptosis of renal tubular cells in mice receiving cisplatin therapy. Meanwhile, the current treatment of SB did not further interfere with the blood cell counts of mice receiving chemotherapy.

CONCLUSION

SB can enhance the anti-cancer effect of cisplatin. It also attenuates cisplatin-induced cachexia and acute kidney injury.

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.

Natural constituents from food sources: potential therapeutic agents against muscle wasting

Skeletal muscle wasting is highly correlated with not only reduced quality of life but also higher morbidity and mortality. Although an increasing number of patients are suffering from various kinds of muscle atrophy and weakness, there is still no effective therapy available, and skeletal muscle is considered as an under-medicated organ. Food provided not only essential macronutrients but also functional substances involved in the modulation of the physiological systems of our body. Natural constituents from commonly consumed dietary plants, either extracts or compounds, have attracted more and more attention to be developed as agents for preventing and treating muscle wasting due to their safety and effectiveness, as well as structural diversity. This review provides an overview of the mechanistic aspects of muscle wasting, and summarizes the extracts and compounds from food sources as potential therapeutic agents against muscle wasting.

Growth Hormone Secretagogues and the Regulation of Calcium Signaling in Muscle

Growth hormone secretagogues (GHS) are a family of synthetic molecules, first discovered in the late 1970s for their ability to stimulate growth hormone (GH) release. Many effects of GHS are mediated by binding to GHS-R1a, the receptor for the endogenous hormone ghrelin, a 28-amino acid peptide isolated from the stomach. Besides endocrine functions, both ghrelin and GHS are endowed with some relevant extraendocrine properties, including stimulation of food intake, anticonvulsant and anti-inflammatory effects, and protection of muscle tissue in different pathological conditions. In particular, ghrelin and GHS inhibit cardiomyocyte and endothelial cell apoptosis and improve cardiac left ventricular function during ischemia–reperfusion injury. Moreover, in a model of cisplatin-induced cachexia, GHS protect skeletal muscle from mitochondrial damage and improve lean mass recovery. Most of these effects are mediated by GHS ability to preserve intracellular Ca²⁺ homeostasis. In this review, we address the muscle-specific protective effects of GHS mediated by Ca²⁺ regulation, but also highlight recent findings of their therapeutic potential in pathological conditions characterized by skeletal or cardiac muscle impairment.

Cancer Takes a Toll on Skeletal Muscle by Releasing Heat Shock Proteins-An Emerging Mechanism of Cancer-Induced Cachexia

Cancer-associated cachexia (cancer cachexia) is a major contributor to the modality and mortality of a wide variety of solid tumors. It is estimated that cachexia inflicts approximately ~60% of all cancer patients and is the immediate cause of ~30% of all cancer-related death. However, there is no established treatment of this disorder due to the poor understanding of its underlying etiology. The key manifestations of cancer cachexia are systemic inflammation and progressive loss of skeletal muscle mass and function (muscle wasting). A number of inflammatory cytokines and members of the TGFβ superfamily that promote muscle protein degradation have been implicated as mediators of muscle wasting. However, clinical trials targeting some of the identified mediators have not yielded satisfactory results. Thus, the root cause of the muscle wasting associated with cancer cachexia remains to be identified. This review focuses on recent progress of laboratory studies in the understanding of the molecular mechanisms of cancer cachexia that centers on the role of systemic activation of Toll-like receptor 4 (TLR4) by cancer-released Hsp70 and Hsp90 in the development and progression of muscle wasting, and the downstream signaling pathways that activate muscle protein degradation through the ubiquitin-proteasome and the autophagy-lysosome pathways in response to TLR4 activation. Verification of these findings in humans could lead to etiology-based therapies of cancer cachexia by targeting multiple steps in this signaling cascade.

A multicenter, open-label, single-arm study of anamorelin (ONO-7643) in advanced gastrointestinal cancer patients with cancer cachexia

Background

Cancer cachexia is characterized by weight loss and is associated with increased morbidity and mortality in patients with cancer. Anamorelin (ONO‐7643; ANAM) is a novel and selective ghrelin receptor agonist that improves appetite, lean body mass (LBM), body weight, and anorexia.

Methods

This multicenter, open‐label, single‐arm study investigated the efficacy and safety of 100 mg anamorelin in 50 Japanese patients with advanced and unresectable gastrointestinal (colorectal, gastric, or pancreatic) cancer. ANAM was administered once daily over 12 weeks. The primary endpoint was the proportion of patients that maintained or gained LBM over the course of the study. Secondary endpoints included changes in LBM, body weight, quality of life (QoL), and nutritional status biomarkers.

Results

The proportion of patients who responded to treatment was 63.3% (95% CI, 48.3%‐76.6%), with a least square mean ± SE change in LBM and body weight from baseline of 1.89 ± 0.36 kg and 1.41 ± 0.61 kg, respectively. Appetite‐related questions on the QoL questionnaire showed that ANAM improved appetite. Adverse events occurred in 79.6% of patients, and the most common treatment‐related adverse events were increased γ‐glutamyl transpeptidase (8.2%), diabetes mellitus (6.1%), hyperglycemia (6.1%), and prolonged QRS complex (6.1%).

Conclusions

ANAM improved anorexia and patients' nutritional status, resulting in rapid increases in LBM and body weight in patients with advanced gastrointestinal cancer who had cancer cachexia. ANAM treatment was well tolerated over 12 weeks. ANAM is a potential clinically beneficial pharmacotherapeutic option for patients with advanced gastrointestinal cancer who have cancer cachexia.

The receipt of 100 mg anamorelin increases lean body mass and improves symptoms of anorexia and nutritional status in patients with advanced gastrointestinal cancer who have cancer cachexia. Anamorelin is well tolerated in these patients.

Myostatin regulates pituitary development and hepatic IGF1

Circulating myostatin-attenuating agents are being developed to treat muscle-wasting disease despite their potential to produce serious off-target effects, as myostatin/activin receptors are widely distributed among many nonmuscle tissues. Our studies suggest that the myokine not only inhibits striated muscle growth but also regulates pituitary development and growth hormone (GH) action in the liver. Using a novel myostatin-null label-retaining model (Jekyll mice), we determined that the heterogeneous pool of pituitary stem, transit-amplifying, and progenitor cells in Jekyll mice depletes more rapidly after birth than the pool in wild-type mice. This correlated with increased levels of GH, prolactin, and the cells that secrete these hormones, somatotropes and lactotropes, respectively, in Jekyll pituitaries. Recombinant myostatin also stimulated GH release and gene expression in pituitary cell cultures although inhibiting prolactin release. In primary hepatocytes, recombinant myostatin blocked GH-stimulated expression of two key mediators of growth, insulin-like growth factor (IGF)1 and the acid labile subunit and increased expression of an inhibitor, IGF-binding protein-1. The significance of these findings was demonstrated by smaller muscle fiber size in a model lacking myostatin and liver IGF1 expression (LID-o-Mighty mice) compared with that in myostatin-null (Mighty) mice. These data together suggest that myostatin may regulate pituitary development and function and that its inhibitory actions in muscle may be partly mediated by attenuating GH action in the liver. They also suggest that circulating pharmacological inhibitors of myostatin could produce unintended consequences in these and possibly other tissues.

Regulation of ghrelin receptor by microbial and inflammatory signals in human osteoblasts

Recently, it has been suggested that the anti-inflammatory hormone ghrelin (GHRL) and its receptor GHS-R may play a pivotal role in periodontal health and diseases. However, their exact regulation and effects in periodontitis are not known. The aim of this in-vitro study was to investigate the effect of microbial and inflammatory insults on the GHS-R1a expression in human osteoblast-like cells. MG-63 cells were exposed to interleukin (IL)-1β and Fusobacterium nucleatum in the presence and absence of GHRL for up to 2 d. Subsequently, gene expressions of GHS-R1a, inflammatory mediators and matrix metalloproteinase were analyzed by real-time PCR. GHS-R protein synthesis and NF-κB p65 nuclear translocation were assessed by immunocytochemistry and immunofluorescence microscopy, respectively. IL-1β and F. nucleatum caused a significant upregulation of GHS-R1a expression and an increase in GHS-R1a protein. Pre-incubation with a MEK1/2 inhibitor diminished the IL-1β-induced GHS-R1a upregulation. IL-1β and F. nucleatum also enhanced the expressions of cyclooxygenase 2, CC-chemokine ligand 2, IL-6, IL-8, and matrix metalloproteinase 1, but these stimulatory effects were counteracted by GHRL. By contrast, the stimulatory actions of IL-1β and F. nucleatum on the GHS-R1a expression were further enhanced by GHRL. Our study provides original evidence that IL-1β and F. nucleatum regulate the GHS-R/GHRL system in osteoblast-like cells. Furthermore, we demonstrate for the first time that the proinflammatory and proteolytic actions of IL-1β and F. nucleatum on osteoblast-like cells are inhibited by GHRL. Our study suggests that microbial and inflammatory insults upregulate GHS-R1a, which may represent a protective negative feedback mechanism in human bone.

Modified Sijunzi decoction can alleviate cisplatin-induced toxicity and prolong the survival time of cachectic mice by recovering muscle atrophy

ETHNOPHARMACOLOGICAL RELEVANCE

Sijunzi decoction is a well-known traditional Chinese medicine (TCM) commonly used for invigorating vital energy and for the enhancement of immunity. Modified Sijunzi decoctions have been extensively used to treat cachexia and improve the quality of life of cancer patients undergoing chemotherapy.

AIM OF THE STUDY

This study was aimed to provide comprehensive evidence for the anti-cachectic effect of a modified Sijunzi decoction (Zhen-Qi; ZQ-SJZ) and characterize its anti-cachectic mechanism, especially in cisplatin-induced muscle atrophy.

MATERIALS AND METHODS

We employed a Lewis lung carcinoma (LLC)-induced cancer cachectic mouse model to demonstrate the anti-cachectic effect of ZQ-SJZ. Moreover, we provided an in vitro C2C12 myotube formation model to investigate the effect of ZQ-SJZ in hampering cisplatin-induced muscle atrophy.

RESULTS

The administration of ZQ-SJZ can recover tumor- and/or cisplatin-induced body weight loss, intestinal mucosal damage, as well as forelimb grip strength and myofiber size. The administration of ZQ-SJZ also significantly prolonged the survival of LLC-induced cachectic mice under cisplatin treatment. Mechanistically, ZQ-SJZ increased the levels of myogenic proteins, such as myosin heavy chain (MyHC) and myogenin, and decreased the atrophy-related protein, atrogin-1, in cisplatin-treated C2C12 myotubes in vitro. In addition, cisplatin-induced mitochondria dysfunction could be hampered by the co-administration of ZQ-SJZ, by which it recovered the cisplatin-mediated decrease in PGC-1α and PKM1 levels.

CONCLUSIONS

The administration of ZQ-SJZ can recover tumor- and/or cisplatin-induced cachectic conditions and significantly prolong the survival of LLC-induced cachectic mice under cisplatin treatment. The profound effect of ZQ-SJZ in hampering tumor- and/or cisplatin-induced cachexia may be due to its modulation of the mitochondrial function and subsequent myogenesis. Taken together, these results demonstrated the anti-cachectic mechanism of ZQ-SJZ and its potential use as a palliative strategy to improve the efficacy of chemotherapy.

PDK4 drives metabolic alterations and muscle atrophy in cancer cachexia

Cachexia is frequently accompanied by severe metabolic derangements, although the mechanisms responsible for this debilitating condition remain unclear. Pyruvate dehydrogenase kinase (PDK)4, a critical regulator of cellular energetic metabolism, was found elevated in experimental models of cancer, starvation, diabetes, and sepsis. Here we aimed to investigate the link between PDK4 and the changes in muscle size in cancer cachexia. High PDK4 and abnormal energetic metabolism were found in the skeletal muscle of colon-26 tumor hosts, as well as in mice fed a diet enriched in Pirinixic acid, previously shown to increase PDK4 levels. Viral-mediated PDK4 overexpression in myotube cultures was sufficient to promote myofiber shrinkage, consistent with enhanced protein catabolism and mitochondrial abnormalities. On the contrary, blockade of PDK4 was sufficient to restore myotube size in C2C12 cultures exposed to tumor media. Our data support, for the first time, a direct role for PDK4 in promoting cancer-associated muscle metabolic alterations and skeletal muscle atrophy.-Pin, F., Novinger, L. J., Huot, J. R., Harris, R. A., Couch, M. E., O'Connell, T. M., Bonetto, A. PDK4 drives metabolic alterations and muscle atrophy in cancer cachexia.

Energy metabolism in cachexia

Cachexia is a wasting disorder that accompanies many chronic diseases including cancer and results from an imbalance of energy requirements and energy uptake. In cancer cachexia, tumor-secreted factors and/or tumor-host interactions cause this imbalance, leading to loss of adipose tissue and skeletal and cardiac muscle, which weakens the body. In this review, we discuss how energy enters the body and is utilized by the different organs, including the gut, liver, adipose tissue, and muscle, and how these organs contribute to the energy wasting observed in cachexia. We also discuss futile cycles both between the organs and within the cells, which are often used to fine-tune energy supply under physiologic conditions. Ultimately, understanding the complex interplay of pathologic energy-wasting circuits in cachexia can bring us closer to identifying effective treatment strategies for this devastating wasting disease.

How to characterize a nasal product. The state of the art of in vitro and ex vivo specific methods

Nasal delivery offers many benefits over other conventional routes of delivery (e.g. oral or intravenous administration). Benefits include, among others, a fast onset of action, non-invasiveness and direct access to the central nervous system. The nasal cavity is not only limited to local application (e.g. rhinosinusitis) but can also provide direct access to other sites in the body (e.g. the central nervous system or systemic circulation). However, both the anatomy and the physiology of the nose impose their own limitations, such as a small volume for delivery or rapid mucociliary clearance. To meet nasal-specific criteria, the formulator has to complete a plethora of tests, in vitro and ex vivo, to assess the efficacy and tolerance of a new drug-delivery system. Moreover, depending on the desired therapeutic effect, the delivery of the drug should target a specific pathway that could potentially be achieved through a modified release of this drug. Therefore, this review focuses on specific techniques that should be performed when a nasal formulation is developed. The review covers both the tests recommended by regulatory agencies (e.g. the Food and Drug Administration) and other complementary experiments frequently performed in the field.

Cachexia induced by cancer and chemotherapy yield distinct perturbations to energy metabolism

BACKGROUND

Cancer cachexia is a metabolic disorder involving perturbed energy balance and altered mitochondrial function. Chemotherapy is a primary treatment option for many types of cancer, but there is substantial evidence that some chemotherapeutic agents can also lead to the development and progression of cachexia. In this study, we apply a comprehensive and systems level metabolomics approach to characterize the metabolic perturbations in murine models of cancer-induced and chemotherapy-induced cachexia. Knowledge of the unique pathways through which cancer and chemotherapy drive cachexia is necessary in order to develop effective treatments.

METHODS

The murine Colon26 (C26) adenocarcinoma xenograft model was used to study the metabolic derangements associated with cancer-induced cachexia. In vivo administration of Folfiri (5-fluorouracil, irinotecan, and leucovorin) was used to model chemotherapy-induced cachexia. Comprehensive metabolic profiling was carried out using both nuclear magnetic resonance-based and mass spectrometry-based platforms. Analyses included plasma, muscle, and liver tissue to provide a systems level profiling.

RESULTS

The study involved four groups of CD2F1 male mice (n = 4-5), including vehicle treated (V), C26 tumour hosts (CC), Folfiri treated (F), and C26 tumour hosts treated with Folfiri (CCF). Significant weight loss including skeletal muscle was observed for each of the experimental groups with the tumour hosts showing the most dramatic change (-3.74 g vs. initial body weight in the CC group). Skeletal muscle loss was evident in all experimental groups compared with V, with the CCF combination resulting in the most severe depletion of quadriceps mass (-38% vs. V; P < 0.001). All experimental groups were characterized by an increased systemic glucose demand as evidenced by decreased levels of circulating glucose (-47% in CC vs. V; P < 0.001) and depletion of liver glucose (-51% in CC vs. V; P < 0.001) and glycogen (-74% in CC vs. V; P < 0.001). The cancer-induced and chemotherapy-induced cachexia models displayed unique alterations in flux through the tricarboxylic acid cycle and β-oxidation pathways. Cancer-induced cachexia was uniquely characterized by a dramatic elevation in low-density lipoprotein particles (+6.9-fold vs. V; P < 0.001) and a significant increase in the inflammatory marker, GlycA (+33% vs. V; P < 0.001).

CONCLUSIONS

The results of this study demonstrated for the first time that cancer-induced and chemotherapy-induced cachexia is characterized by a number of distinct metabolic derangements. Effective therapeutic interventions for cancer-induced and chemotherapy-induced cachexia must take into account the specific metabolic defects imposed by the pathological or pharmacological drivers of cachexia.

Moderate exercise in mice improves cancer plus chemotherapy-induced muscle wasting and mitochondrial alterations

Cancer cachexia is a multifactorial syndrome characterized by anorexia, body wasting, and muscle and adipose tissue loss, impairing patient's tolerance to anticancer treatments and survival. The aim of the present study was to compare the effects induced in mice by tumor growth alone (C26) or in combination with chemotherapy [C26 oxaliplatin and 5-fluorouracil (oxfu)] and to evaluate the potential of moderate exercise. Oxfu administration to C26 mice exacerbated muscle wasting and triggered autophagy or mitophagy, decreased protein synthesis, and induced mitochondrial alterations. Exercise in C26 oxfu mice counteracted the loss of muscle mass and strength, partially rescuing autophagy and mitochondrial function. Nevertheless, exercise worsened survival in C26 oxfu mice in late stages of cachexia. In summary, chemotherapy further impinges on cancer-induced alterations, worsening muscle wasting. An ideal multifactorial and early intervention to prevent cancer cachexia could take advantage of exercise, improving patient's energy metabolism, mobility, and quality of life.-Ballarò, R., Beltrà, M., De Lucia, S., Pin, F., Ranjbar, K., Hulmi, J. J., Costelli, P., Penna, F. Moderate exercise in mice improves cancer plus chemotherapy-induced muscle wasting and mitochondrial alterations.

Bisphosphonate Treatment Ameliorates Chemotherapy-Induced Bone and Muscle Abnormalities in Young Mice

Chemotherapy is frequently accompanied by several side effects, including nausea, diarrhea, anorexia and fatigue. Evidence from ours and other groups suggests that chemotherapy can also play a major role in causing not only cachexia, but also bone loss. This complicates prognosis and survival among cancer patients, affects quality of life, and can increase morbidity and mortality rates. Recent findings suggest that soluble factors released from resorbing bone directly contribute to loss of muscle mass and function secondary to metastatic cancer. However, it remains unknown whether similar mechanisms also take place following treatments with anticancer drugs. In this study, we found that young male CD2F1 mice (8-week old) treated with the chemotherapeutic agent cisplatin (2.5 mg/kg) presented marked loss of muscle and bone mass. Myotubes exposed to bone conditioned medium from cisplatin-treated mice showed severe atrophy (-33%) suggesting a bone to muscle crosstalk. To test this hypothesis, mice were administered cisplatin in combination with an antiresorptive drug to determine if preservation of bone mass has an effect on muscle mass and strength following chemotherapy treatment. Mice received cisplatin alone or combined with zoledronic acid (ZA; 5 μg/kg), a bisphosphonate routinely used for the treatment of osteoporosis. We found that cisplatin resulted in progressive loss of body weight (-25%), in line with reduced fat (-58%) and lean (-17%) mass. As expected, microCT bone histomorphometry analysis revealed significant reduction in bone mass following administration of chemotherapy, in line with reduced trabecular bone volume (BV/TV) and number (Tb.N), as well as increased trabecular separation (Tb.Sp) in the distal femur. Conversely, trabecular bone was protected when cisplatin was administered in combination with ZA. Interestingly, while the animals exposed to chemotherapy presented significant muscle wasting (~-20% vs. vehicle-treated mice), the administration of ZA in combination with cisplatin resulted in preservation of muscle mass (+12%) and strength (+42%). Altogether, these observations support our hypothesis of bone factors targeting muscle and suggest that pharmacological preservation of bone mass can benefit muscle mass and function following chemotherapy.

Chemotherapy-induced loss of bone and muscle mass in a mouse model of breast cancer bone metastases and cachexia

BACKGROUND

Chemotherapy used to treat malignancy can lead to loss of skeletal muscle mass and reduced force production, and can reduce bone volume in mice. We have shown that bone-muscle crosstalk is a key nexus in skeletal muscle function and bone homeostasis in osteolytic breast cancer bone metastases. Because chemotherapy has significant negative side effects on bone mass, and because bone loss can drive skeletal muscle weakness, we have examined the effects of chemotherapy on the musculoskeletal system in mice with breast cancer bone metastases.

METHODS AND RESULTS

Six-week-old Female athymic nude mice were inoculated with 10⁵ MDA-MB231 human breast cancer cells into the left ventricle and bone metastases were confirmed by X-ray. Mice were injected with carboplatin at a dose of 60mg/kg once per week starting 4 days after tumor inoculation. Skeletal muscle was collected for biochemical analysis and extensor digitorum longus (EDL) whole muscle contractility was measured. The femur and tibia bone parameters were assessed by microCT and tumor burden in bone was determined by histology. Healthy mice treated with carboplatin lose whole body weight and have reduced individual muscle weights (gastrocnemius, tibialis anterior (TA), and EDL), reduced trabecular bone volume (BV/TV), and reduced EDL function. Mice with MDA-MB-231 bone metastases treated with carboplatin lose body weight, and have reduced EDL function as healthy mice treated with carboplatin. Mice with MDA-MB-231 bone metastases plus carboplatin do have reduced proximal tibia BV/TV compared to carboplatin alone, but carboplatin does reduce tumor burden in bone.

CONCLUSIONS

Our data shows that carboplatin treatment, aimed at reducing tumor burden, contributes to cachexia and trabecular bone loss. The muscle atrophy and weakness may occur through bone-muscle crosstalk and would lead to a feed-forward cycle of musculoskeletal degradation. Despite anti-tumor effects of chemotherapy, musculoskeletal impairment is still significant in mice with bone metastases.