Elevated circulating level of ghrelin in cachexia associated with chronic heart failure: relationships between ghrelin and anabolic/catabolic factors

Relationship between cachexia and short physical performance battery scores in patients with heart failure attending comprehensive outpatient cardiac rehabilitation

Heart failure (HF) can cause metabolic imbalances, leading to anabolic resistance and increased energy expenditure, which often results in weight loss and cachexia. Comprehensive cardiac rehabilitation (CR), including exercise, nutritional support, and risk management, is crucial for enhancing the health and quality of life of patients with HF and is expected to play a central role in the prevention and treatment of HF-associated cachexia. However, the prevalence of cachexia in patients with HF undergoing comprehensive outpatient CR is currently unknown, and the detailed characteristics including of motor function of such patients remain undefined. Therefore, this cross-sectional study aimed to investigate the prevalence and characteristics of cachexia and the relationship between cachexia and lower limb motor function in patients with HF undergoing outpatient CR. This study included 115 consecutive patients with HF (43% male; mean age, 78 ± 8 years) who underwent comprehensive outpatient CR. The cachexia status was assessed according to the definition proposed by the Asian Working Group on Cachexia in 2023. The Short Physical Performance Battery (SPPB) and Mini Nutritional Assessment Short-Form (MNA-SF) were used to evaluate motor function of the lower limbs and nutritional status, respectively. Multivariate logistic regression analyses were used to examine the potential relationship between cachexia and low SPPB scores (≤ 9 points). The prevalence of cachexia was 30% in this study. Compared with those without cachexia, patients with cachexia were significantly older and showed notable reductions in body mass index, MNA-SF scores, handgrip strength, gait speed, and SPPB scores. A multivariate logistic regression analysis, adjusted for confounders, revealed that both age (odds ratio [OR], 1.129; 95% confidence interval [CI], 1.034-1.248; P = 0.016) and presence of cachexia (OR, 3.783; 95% CI, 1.213-11.796; P = 0.022) were independently associated with low SPPB scores. These findings highlight the importance of focusing on cachexia in patients with HF as part of a comprehensive outpatient CR and may be crucial in developing treatments to improve lower limb motor function in patients with HF who develops cachexia.

Increased Expression of Proinflammatory Genes in Peripheral Blood Cells Is Associated with Cardiac Cachexia in Patients with Heart Failure with Reduced Ejection Fraction

Background: Cardiac cachexia (CC) in chronic heart failure with reduced ejection fraction (HFrEF) is characterized by catabolism and inflammation predicting poor prognosis. Levels of responsible transcription factors like signal transducer and activator of transcription (STAT)1, STAT3, suppressor of cytokine signaling (SOCS)1 and SOCS3 in peripheral blood cells (PBC) are underinvestigated in CC. Expression of mediators was related to patients' functional status, body composition (BC) and metabolic gene expression in skeletal muscle (SM). Methods: Gene expression was quantified by qRT-PCR in three cohorts: non-cachectic patients (ncCHF, n = 19, LVEF 31 ± 7%, BMI 30.2 ± 5.0 kg/m2), cachectic patients (cCHF; n = 18, LVEF 27 ± 7%, BMI 24.3 ± 2.5 kg/m2) and controls (n = 17, LVEF 70 ± 7%, BMI 27.6 ± 4.6 kg/m2). BC was assessed by dual-energy X-ray absorptiometry. Blood inflammatory markers were measured. We quantified solute carrier family 2 member 4 (SLC2A4) and protein degradation by expressions of proteasome 20S subunit beta 2 and calpain-1 catalytic subunit in SM biopsies. Results: TNF and IL-10 expression was higher in cCHF than in ncCHF and controls (all p < 0.004). cCHF had a lower fat mass index (FMI) and lower fat-free mass index (FFMI) compared to ncCHF and controls (p < 0.05). STAT1 and STAT3 expression was higher in cCHF vs. ncCHF or controls (1.1 [1.6] vs. 0.8 [0.9] vs. 0.9 [1.1] RU and 4.6 [5.5] vs. 2.5 [4.8] vs. 3.0 [4.2] RU, all ANOVA-p < 0.05). The same applied for SOCS1 and SOCS3 expression (1.1 [1.5] vs. 0.4 [0.4] vs. 0.4 [0.5] and 0.9 [3.3] vs. 0.4 [1.1] vs. 0.8 [0.9] RU, all ANOVA-p < 0.04). In cCHF, higher TNF and STAT1 expression was associated with lower FMI (r = 0.5, p = 0.053 and p < 0.05) but not with lower FFMI (p > 0.4). In ncCHF, neither cytokine nor STAT/SOCS expression was associated with BC (all p > 0.3). SLC2A4 was upregulated in SM of cCHF vs. ncCHF (p < 0.03). Conclusions: Increased STAT1, STAT3, SOCS1 and SOCS3 expression suggests their involvement in CC. In cCHF, higher TNF and STAT-1 expression in PBC were associated with lower FMI. Increased SLC2A4 in cachectic SM biopsies indicates altered glucose metabolism.

Prognostic impact of cachexia by multi-assessment in older adults with heart failure: FRAGILE-HF cohort study

BACKGROUND

Cachexia substantially impacts the prognosis of patients with heart failure (HF); however, there is no standard method for cachexia diagnosis. This study aimed to investigate the association of Evans's criteria, consisting of multiple assessments, with the prognosis of HF in older adults.

METHODS

This study is a secondary analysis of the data from the FRAGILE-HF study, a prospective multicentre cohort study that enrolled consecutive hospitalized patients aged ≥65 years with HF. Patients were divided into two groups: the cachexia and non-cachexia groups. Cachexia was defined according to Evans's criteria by assessing weight loss, muscle weakness, fatigue, anorexia, a decreased fat-free mass index and an abnormal biochemical profile. The primary outcome was all-cause mortality, as assessed in the survival analysis.

RESULTS

Cachexia was present in 35.5% of the 1306 enrolled patients (median age [inter-quartile range], 81 [74-86] years; 57.0% male); 59.6%, 73.2%, 15.6%, 71.0%, 44.9% and 64.6% had weight loss, decreased muscle strength, a low fat-free mass index, abnormal biochemistry, anorexia and fatigue, respectively. All-cause mortality occurred in 270 patients (21.0%) over 2 years. The cachexia group (hazard ratio [HR], 1.494; 95% confidence interval [CI], 1.173-1.903; P = 0.001) had a higher mortality risk than the non-cachexia group after adjusting for the severity of HF. Cardiovascular and non-cardiovascular deaths occurred in 148 (11.3%) and 122 patients (9.3%), respectively. The adjusted HRs for cachexia in cardiovascular mortality and non-cardiovascular mortality were 1.456 (95% CI, 1.048-2.023; P = 0.025) and 1.561 (95% CI, 1.086-2.243; P = 0.017), respectively. Among the cachexia diagnostic criteria, decreased muscle strength (HR, 1.514; 95% CI, 1.095-2.093; P = 0.012) and low fat-free mass index (HR, 1.424; 95% CI, 1.052-1.926; P = 0.022) were significantly associated with high all-cause mortality, but there was no significant association between weight loss alone (HR, 1.147; 95% CI, 0.895-1.471; P = 0.277) and all-cause mortality.

CONCLUSIONS

Cachexia evaluated by multi-assessment was present in one third of older adults with HF and was associated with a worse prognosis. A multimodal assessment of cachexia may be helpful for risk stratification in older patients with HF.

The role of frailty in advanced HF and cardiac transplantation

Frailty is a complex, multi-system condition often associated with multimorbidity. It has become an important prognostic maker across a range of conditions and is particularly relevant in patients with cardiovascular disease. Frailty encompasses a range of domains including, physical, psychological, and social. There are currently a range of validated tools available to measure frailty. It is an especially important measurement in advanced HF, because frailty occurs in up to 50% of HF patients and is potentially reversible with therapies such as mechanical circulatory support and transplantation. Moreover, frailty is dynamic, and therefore serial measurements are important. This review delves into the measurement of frailty, mechanisms, and its role in different cardiovascular cohorts. Understanding frailty will help determine patients that will benefit from therapies, as well as prognosticate outcomes.

Gut Molecules in Cardiometabolic Diseases: The Mechanisms behind the Story

Atherosclerotic cardiovascular disease is the most common cause of morbidity and mortality worldwide. Diabetes mellitus increases cardiovascular risk. Heart failure and atrial fibrillation are associated comorbidities that share the main cardiovascular risk factors. The use of incretin-based therapies promoted the idea that activation of alternative signaling pathways is effective in reducing the risk of atherosclerosis and heart failure. Gut-derived molecules, gut hormones, and gut microbiota metabolites showed both positive and detrimental effects in cardiometabolic disorders. Although inflammation plays a key role in cardiometabolic disorders, additional intracellular signaling pathways are involved and could explain the observed effects. Revealing the involved molecular mechanisms could provide novel therapeutic strategies and a better understanding of the relationship between the gut, metabolic syndrome, and cardiovascular diseases.

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.

Molecular Mechanisms and Health Benefits of Ghrelin: A Narrative Review

Ghrelin, an endogenous brain-gut peptide, is secreted in large quantities, mainly from the stomach, in humans and rodents. It can perform the biological function of activating the growth hormone secretagogue receptor (GHSR). Since its discovery in 1999, ample research has focused on promoting its effects on the human appetite and pleasure-reward eating. Extensive, in-depth studies have shown that ghrelin is widely secreted and distributed in tissues. Its role in neurohumoral regulation, such as metabolic homeostasis, inflammation, cardiovascular regulation, anxiety and depression, and advanced cancer cachexia, has attracted increasing attention. However, the effects and regulatory mechanisms of ghrelin on obesity, gastrointestinal (GI) inflammation, cardiovascular disease, stress regulation, cachexia treatment, and the prognosis of advanced cancer have not been fully summarized. This review summarizes ghrelin's numerous effects in participating in a variety of biochemical pathways and the clinical significance of ghrelin in the regulation of the homeostasis of organisms. In addition, potential mechanisms are also introduced.

The importance of biological sex in cardiac cachexia

Cardiac cachexia is a catabolic muscle wasting syndrome observed in approximately 1 in 10 heart failure patients. Increased skeletal muscle atrophy leads to frailty and limits mobility which impacts quality of life, exacerbates clinical care, and is associated with higher rates of mortality. Heart failure is known to exhibit a wide range of prevalence and severity when examined across individuals of different ages and with co-morbidities related to diabetes, renal failure and pulmonary dysfunction. It is also recognized that men and women exhibit striking differences in the pathophysiology of heart failure as well as skeletal muscle homeostasis. Given that both skeletal muscle and heart failure physiology are in-part sex dependent, the diagnosis and treatment of cachexia in heart failure patients may depend on a comprehensive examination of how these organs interact. In this review we explore the potential for sex-specific differences in cardiac cachexia. We summarize advantages and disadvantages of clinical methods used to measure muscle mass and function and provide alternative measurements that should be considered in preclinical studies. Additionally, we summarize sex-dependent effects on muscle wasting in preclinical models of heart failure, disuse, and cancer. Lastly, we discuss the endocrine function of the heart and outline unanswered questions that could directly impact patient care.

Heart Failure and Pancreas Exocrine Insufficiency: Pathophysiological Mechanisms and Clinical Point of View

Heart failure is associated with decreased tissue perfusion and increased venous congestion that may result in organ dysfunction. This dysfunction has been investigated extensively for many organs, but data regarding pancreatic (exocrine) dysfunction are scarce. In the present review we will discuss the available data on the mechanisms of pancreatic damage, how heart failure can lead to exocrine dysfunction, and its clinical consequences. We will show that heart failure causes significant impairment of pancreatic exocrine function, particularly in the elderly, which may exacerbate the clinical syndrome of heart failure. In addition, pancreatic exocrine insufficiency may lead to further deterioration of cardiovascular disease and heart failure, thus constituting a true vicious circle. We aim to provide insight into the pathophysiological mechanisms that constitute this reciprocal relation. Finally, novel treatment options for pancreatic dysfunction in heart failure are discussed.

Exploring the prevalence, impact and experience of cardiac cachexia in patients with advanced heart failure and their caregivers: A sequential phased study

BACKGROUND

Cardiac Cachexia is a wasting syndrome that has a significant impact on patient mortality and quality of life world-wide, although it is poorly understood in clinical practice.

AIM

Identify the prevalence of cardiac cachexia in patients with advanced New York Heart Association (NYHA) functional class and explore its impact on patients and caregivers.

DESIGN

An exploratory cross-sectional study. The sequential approach had two phases, with phase 1 including 200 patients with NYHA III-IV heart failure assessed for characteristics of cardiac cachexia. Phase 2 focussed on semi-structured interviews with eight cachectic patients and five caregivers to ascertain the impact of the syndrome.

SETTING/PARTICIPANTS

Two healthcare trusts within the United Kingdom.

RESULTS

Cardiac Cachexia was identified in 30 out of 200 participants, giving a prevalence rate of 15%. People with cachexia had a significantly reduced average weight and anthropometric measures (p < 0.05). Furthermore, individuals with cachexia experienced significantly more fatigue, had greater issues with diet and appetite, reduced physical wellbeing and overall reduced quality of life. C-reactive protein was significantly increased, whilst albumin and red blood cell count were significantly decreased in the cachectic group (p < 0.05). From qualitative data, four key themes were identified: (1) 'Changed relationship with food and eating', (2) 'Not me in the mirror', (3) 'Lack of understanding regarding cachexia' and (4) 'Uncertainty regarding the future'.

CONCLUSIONS

Cardiac cachexia has a debilitating effect on patients and caregivers. Future work should focus on establishing a specific definition and clinical pathway to enhance patient and caregiver support.

Cancer- and cardiac-induced cachexia: same fate through different inflammatory mediators?

BACKGROUND

Inflammation is widely recognized as the driving force of cachexia induced by chronic diseases; however, therapies targeting inflammation do not always reverse cachexia. Thus, whether inflammation per se plays an important role in the clinical course of cachectic patients is still a matter of debate.

AIMS

To give new insights into cachexia's pathogenesis and diagnosis, we performed a comprehensive literature search on the contribution of inflammatory markers to this syndrome, focusing on the noncommunicable diseases cancer and cardiovascular diseases.

METHODS

A systematic review was performed in PubMed using the keywords ("cancer" OR "cardiac" cachexia AND "human" OR "patient" AND "plasma" or "serum"). A total of 744 studies were retrieved and, from these, 206 were selected for full-text screening. In the end, 98 papers focusing on circulating biomarkers of cachexia were identified, which resulted in a list of 113 different mediators.

RESULTS

Data collected from the literature highlight the contribution of interleukin-6 (IL-6) and C-reactive protein (CRP) to cachexia, independently of the underlying condition. Despite not being specific, once the diagnosis of cachexia is established, CRP might help to monitor the effectiveness of anti-cachexia therapies. In cardiac diseases, B-type natriuretic peptide (BNP), renin, and obestatin might be putative markers of body wasting, whereas in cancer, growth differentiation factor (GDF) 15, transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF) C seem to be better markers of this syndrome. Independently of the circulating mediators, NF-κB and JAK/STAT signaling pathways play a key role in bridging inflammation with muscle wasting; however, therapies targeting these pathways were not proven effective for all cachectic patients.

CONCLUSION

The critical and integrative analysis performed herein will certainly feed future research focused on the better comprehension of cachexia pathogenesis toward the improvement of its diagnosis and the development of personalized therapies targeting specific cachexia phenotypes.

Pharmacotherapy in Cachexia: A Review of Endocrine Abnormalities and Steroid Pharmacotherapy

Cachexia is a state of increased metabolism associated with high morbidity and mortality. Dysregulation of cytokines and hormone activity causes reduced protein synthesis and excessive protein breakdown. various treatments are available, depending on the primary disease and the patient's state. Besides pharmacological treatment, crucial is nutritional support as well as increasing physical activity. The main purpose of pharmacological treatment is to diminish inflammation, improve appetite and decrease muscle wasting. Therefore a lot of medications aim at proinflammatory cytokines such as Interferon-α or Tumor Necrosis Factor-β, but because of the complicated mechanism of cachexia, the range of targets is very wide. in cachexia treatment, use of corticosteroids is common, which improve appetite, diminish inflammation, inhibit prostaglandin metabolism, Interleukin-1 activity. They can also decrease protein synthesis and increase protein degradation, which can be prevented by resveratrol. Estrogen analogs, progesterone analogs, testosterone analogs, Selective Androgen Receptor Modulators (SARM), Angiotensin-Converting-Enzyme Inhibitors (ACEI), Nonsteroidal anti-inflammatory drugs (NSAIDs), thalidomide, melatonin, Growth Hormone Releasing Peptide-2 (GHRP-2) may play important role in wasting syndrome treatment as well. However, for the usage of some of them, evidence-based recommendations are not available. This review highlights current therapeutic options for cachexia with a specific focus on steroid therapy.

Interconnection between Cardiac Cachexia and Heart Failure—Protective Role of Cardiac Obesity

Cachexia may be caused by congestive heart failure, and it is then called cardiac cachexia, which leads to increased morbidity and mortality. Cardiac cachexia also worsens skeletal muscle degradation. Cardiac cachexia is the loss of edema-free muscle mass with or without affecting fat tissue. It is mainly caused by a loss of balance between protein synthesis and degradation, or it may result from intestinal malabsorption. The loss of balance in protein synthesis and degradation may be the consequence of altered endocrine mediators such as insulin, insulin-like growth factor 1, leptin, ghrelin, melanocortin, growth hormone and neuropeptide Y. In contrast to many other health problems, fat accumulation in the heart is protective in this condition. Fat in the heart can be divided into epicardial, myocardial and cardiac steatosis. In this review, we describe and discuss these topics, pointing out the interconnection between heart failure and cardiac cachexia and the protective role of cardiac obesity. We also set the basis for possible screening methods that may allow for a timely diagnosis of cardiac cachexia, since there is still no cure for this condition. Several therapeutic procedures are discussed including exercise, nutritional proposals, myostatin antibodies, ghrelin, anabolic steroids, anti-inflammatory substances, beta-adrenergic agonists, medroxyprogesterone acetate, megestrol acetate, cannabinoids, statins, thalidomide, proteasome inhibitors and pentoxifylline. However, to this date, there is no cure for cachexia.

Ghrelin and ghrelin/total cholesterol ratio as independent predictors for coronary artery disease: a systematic review and meta-analysis

The present meta-analysis aimed to summarize the available data regarding the circulating levels of ghrelin in patients with cardiovascular diseases (CVDs). A comprehensive search was performed in electronic databases including PubMed, Scopus, EMBASE, and Web of Science up to January 20, 2021. Since the circulating levels of ghrelin were measured in different units across the included studies, they were expressed as the standardized mean difference (SMD) and 95% CI (summary effect size). A random-effects model comprising the DerSimonian and Laird method was used to pool SMDs. Sixteen articles (20 studies) comprised of 1087 cases and 437 controls were included. The pooled results showed that there were no significant differences between cases and controls in terms of ghrelin levels (SMD=-0.61, 95% CI -1.38 to 0.16; p=0.120; I²=96.9%, p<0.001). The ghrelin concentrations in the CAD stratum were significantly lower than in controls, whereas they increased in other disease strata. New combined biomarkers demonstrated a significant decrease in the SMD of the ghrelin/total cholesterol (TC) ratio (-1.02; 95% CI -1.74 to -0.29, p=0.000; I²=94.5%). However, no significant differences were found in the SMD of the ghrelin/high-density lipoprotein cholesterol ratio, ghrelin/low-density lipoprotein cholesterol ratio, and ghrelin/triglyceride (TG) ratio in cases with CVDs compared with the control group. Ghrelin was associated with CAD; therefore, it may be considered a biomarker for distinguishing between patients with and without CAD. Furthermore, the ghrelin/TC ratio could be proposed as a diagnostic marker for CVD.

Kampo medicine for the holistic approach to older adults with heart failure

Heart failure (HF) is a leading cause of hospitalization, morbidity, and mortality in older adults and represents a significant clinical and economic burden on the health care system. However, there are many challenges in assessing and managing HF in elderly patients, who often have coexisting multimorbidity, frailty, and malnutrition. Therefore, it is often difficult to solve these problems with Western medicine alone, and a holistic approach, including Kampo medicine, can be helpful. In particular, managing volume control and frailty by adding Kampo formulas may help improve health-related quality of life and substantially impact prognosis in HF. This review article summarizes the role of Kampo medicine for older patients with HF and frailty.

Temporal changes and prognostic value of plasma ghrelin level in patients with acute heart failure: a prospective study

BACKGROUND

Plasma ghrelin levels can be elevated in patients with acute heart failure (AHF). This study aimed to analyze the temporal changes and prognostic value of ghrelin levels in patients with AHF.

METHODS

This prospective study included patients with AHF at the Cardiology Department, Weifang People's Hospital (May 2018-October 2019), and age- and sex-matched healthy controls. Plasma ghrelin levels were measured. Multivariable logistic regression and receiver operating characteristic (ROC) curve analyses were used to evaluate whether ghrelin levels could predict major cardiac adverse events (MACEs) during a 1-year follow-up.

RESULTS

Finally, 92 patients with AHF and 50 healthy controls were enrolled. Ghrelin levels were higher in patients with AHF at 1, 3, 12, and 24 h compared with controls (all P < 0.01). Ghrelin levels in the AHF group were higher at 3 and 12 h than at 1 and 24 h (P < 0.001). Ghrelin level at 3 h in patients with AHF was negatively correlated with the left ventricular end-diastolic diameter and left ventricular ejection fraction (both P < 0.05). MACEs occurred in 48 patients with AHF. Ghrelin levels were higher in the MACE group than in the non-MACE group at 1 (P = 0.011) and 3 h (P = 0.034). Multivariable regression showed that ghrelin level at 3 h was independently associated with MACEs [OR = 0.629, 95% confidence interval (CI): 0.515-0.742, P = 0.010], but the area under the ROC curve was only 0.629 (95% CI 0.515-0.742).

CONCLUSIONS

Plasma ghrelin levels are elevated in AHF and patients with MACEs during follow-up.

Relevance of nutritional assessment and treatment to counteract cardiac cachexia and sarcopenia in chronic heart failure

Chronic heart failure (CHF) is frequently associated with the involuntary loss of body weight and muscle wasting, which can determine the course of the disease and its prognosis. While there is no gold standard malnutrition screening tool for their detection in the CHF population, several bioelectrical and imaging methods have been used to assess body composition in these patients (such as Dual Energy X-Ray Absorptiometry and muscle ultrasound, among other techniques). In addition, numerous nutritional biomarkers have been found to be useful in the determination of the nutritional status. Nutritional considerations include the slow and progressive supply of nutrients, avoiding high volumes, which could ultimately lead to refeeding syndrome and worsen the clinical picture. If oral feeding is insufficient, hypercaloric and hyperproteic supplementation should be considered. β-Hydroxy-β-methylbutyrate and omega-3 polyunsaturated fatty acid administration prove to be beneficial in certain patients with CHF, and several interventional studies with micronutrient supplementation have also described their possible role in these subjects. Taking into account that CHF is sometimes associated with gastrointestinal dysfunction, parenteral nutritional support may be required in selected cases. In addition, potential therapeutic options regarding nutritional state and muscle wasting have also been tested in clinical studies. This review summarises the scientific evidence that demonstrates the necessity to carry out a careful nutritional evaluation and nutritional treatment to prevent or improve cardiac cachexia and sarcopenia in CHF, as well as improve its course.

GHSR deficiency exacerbates cardiac fibrosis: role in macrophage inflammasome activation and myofibroblast differentiation

AIMS

Sustained activation of β-adrenergic signalling induces cardiac fibrosis, which marks progression to heart failure. GHSR (growth hormone secretagogue receptor) is the receptor for ghrelin, which is an orexigenic gastric hormone with newly defined cardiovascular effects. The present study determined the effects of GHSR deficiency in a mouse model of isoproterenol (ISO)-induced cardiac fibrosis and examined the underlying mechanism.

METHODS AND RESULTS

Histochemical studies showed that GHSR deficiency exacerbated cardiac fibrosis. Quantitative RT-PCR, western blotting, and immunofluorescence staining demonstrated that cardiac fibroblasts isolated from GHSR-/- mice exhibited increased expression of marker genes for myofibroblast trans-differentiation (α-SMA, SM22, and calponin) upon transforming growth factor-β treatment compared to wild-type mice. RNA-sequencing of heart transcriptomes revealed that differentially expressed genes in GHSR-/- hearts were enriched in such biological processes as extracellular matrix organization, inflammatory response, lipid metabolism, cell cycle, migration, and adhesion. Particularly, GHSR deficiency increased Wnt/β-catenin pathway activation in ISO-induced myocardial fibrosis. In addition, loss of GHSR in macrophages instigated inflammasome activation with increased cleavage and release of interleukin-18.

CONCLUSION

These results for the first time demonstrated that GHSR deficiency aggravated ISO-induced cardiac fibrosis, suggesting that GHSR was a potential target for the intervention of cardiac fibrosis.

Ghrelin Response to Acute and Chronic Exercise: Insights and Implications from a Systematic Review of the Literature

BACKGROUND

Ghrelin is a peptide hormone predominantly produced by the stomach. It exerts a wide range of functions including stimulating growth hormone release and regulating appetite, food intake, and glucose and lipid metabolism. Since physical exercise affects all these aspects, a particular interest is accorded to the relationship between ghrelin and exercise. This systematic review aimed to summarize the current available data on the topic for a better understanding of the relationship.

METHODS

An extensive computerized search was performed in the PubMed and SPORTDiscus databases for retrieving relevant articles. The search contained the following keywords: ghrelin, appetite-related peptides, gastrointestinal peptides, gastrointestinal hormones, exercise, acute exercise, chronic exercise, training, and physical activity. Studies investigating the effects of acute/chronic exercise on circulating forms of ghrelin were included.

RESULTS

The initial search identified 840 articles. After screening, 80 articles were included. Despite a heterogeneity of studies and a variability of the findings, the review suggests that acute exercise suppresses acyl ghrelin production regardless of the participants and the exercise characteristics. Long- and very long-term exercise training programs mostly resulted in increased total and des-acyl ghrelin production. The increase is more noticeable in overweight/obese individuals, and is most likely due to weight loss resulting from the training program.

CONCLUSION

The review suggests that exercise may impact ghrelin production. While the precise mechanisms are unclear, the effects are likely due to blood flow redistribution and weight loss for acute and chronic exercise, respectively. These changes are expected to be metabolically beneficial. Further research is needed for a better understanding of the relationship between ghrelin and exercise.

MECHANISMS IN ENDOCRINOLOGY: The gut-brain axis: regulating energy balance independent of food intake

Obesity is a global pandemic with a large health and economic burden worldwide. Bodyweight is regulated by the ability of the CNS, and especially the hypothalamus, to orchestrate the function of peripheral organs that play a key role in metabolism. Gut hormones play a fundamental role in the regulation of energy balance, as they modulate not only feeding behavior but also energy expenditure and nutrient partitioning. This review examines the recent discoveries about hormones produced in the stomach and gut, which have been reported to regulate food intake and energy expenditure in preclinical models. Some of these hormones act on the hypothalamus to modulate thermogenesis and adiposity in a food intake-independent fashion. Finally, the association of these gut hormones to eating, energy expenditure, and weight loss after bariatric surgery in humans is discussed.

Ghrelin hormone might have a potential role in amelogenesis

AIMS

Amelogenesis imperfecta and generalised enamel hypoplasia are developmental dental anomalies that affect dental enamel. While amelogenesis imperfecta results from various gene mutations, the exact underlying mechanisms of the etiopathogenesis of both remain unclear. This study aims to evaluate Ghrelin hormone levels in children with generalised enamel hypoplasia to establish whether Ghrelin might have a potential role in enamel hypoplasia's etiology. The second purpose is to determine the correlations among the blood levels of Ghrelin, growth hormone (GH), insulin-like growth factor-1 (IGF-1), bone alkaline phosphatase (BALP) and osteocalcin (OC) that are vital in dental development.

MATERIAL AND METHODS

Study was designed with two study groups, AI (hypoplastic amelogenesis imperfecta) (n = 15; mean-age 10.36 ± 1.90) and GEH (idiopathic generalised enamel hypoplasia) (n = 15; mean-age 10.42 ± 1.84), and a healthy control (n = 15; mean-age 10.39 ± 1.91) group. After fasting for 10-12 hours, simultaneous blood samples were collected; then, after centrifugation, serum and plasma were stored at -80°C until the day of analysis. Total Ghrelin levels of plasma and serum levels of GH, IGF-1, BALP and OC were measured using commercial ELISA kits.

RESULTS

Ghrelin levels of AI and GEH groups were significantly lower (P < .01) than the control group.

CONCLUSION

This is the first study to reveal the decreased levels of Ghrelin in plasma of children with generalised enamel hypoplasia, suggesting a potential role for Ghrelin in amelogenesis. In order to determine its function in enamel formation, further studies should be carried out. The result of the present study suggests that paediatricians refer children with abnormal Ghrelin levels to a paediatric dentist to contribute to appropriate prophylactic and therapeutic interventions. Generalised enamel hypoplasia may also indicate possible abnormalities in Ghrelin levels for paediatricians. Therefore, paediatricians' knowledge about the clinical appearance of generalised enamel hypoplasia should be increased.

How progressive cancer endangers the heart: an intriguing and underestimated problem

Since it came into being as a discipline, cardio-oncology has focused on the prevention and treatment of cardiotoxicity induced by antitumor chemotherapy and radiotherapy. Over time, it has been proved that even more detrimental is the direct effect generated by cancer cells that release pro-cachectic factors in the bloodstream. Secreted molecules target different organs at a distance, including the heart. Inflammatory and neuronal modulators released by the tumor bulk, either as free molecules or through exosomes, contribute to the pathogenesis of cardiac disease. Progressive cancer causes cachexia and severe cardiac muscle wasting accompanied by cardiomyocyte atrophy, tissue fibrosis, and several functional impairments up to heart failure. The molecular mechanisms responsible for such a cardiac muscle wasting have been partially elucidated in animal models, but minimally investigated in humans, although severe cardiac dysfunction exacerbates global cachexia and hampers efficient anti-cancer treatments. This review provides an overview of cancer-induced structural cardiac and functional damage, drawing on both clinical and scientific research. We start by looking at the pathophysiological mechanisms and evolving epidemiology and go on to discuss prevention, diagnosis, and a multimodal policy of intervention aimed at providing overall prognosis and global care for patients. Despite much interest in the cardiotoxicity of cancer therapies, the direct tumor effect on the heart remains poorly explored. There is still a lack of diagnostic criteria for the identification of the early stages of cardiac disease in cancer patients, while the possibilities that there are for effective prevention are largely underestimated. Research on innovative therapies has claimed considerable advances in preclinical studies, but none of the molecular targets suitable for clinical application has been approved for therapy. These issues are critically discussed here.

Inflammation and Skeletal Muscle Wasting During Cachexia

Cachexia is the involuntary loss of muscle and adipose tissue that strongly affects mortality and treatment efficacy in patients with cancer or chronic inflammatory disease. Currently, no specific treatments or interventions are available for patients developing this disorder. Given the well-documented involvement of pro-inflammatory cytokines in muscle and fat metabolism in physiological responses and in the pathophysiology of chronic inflammatory disease and cancer, considerable interest has revolved around their role in mediating cachexia. This has been supported by association studies that report increased levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in some, but not all, cancers and in chronic inflammatory diseases such as chronic obstructive pulmonary disease (COPD) and rheumatoid arthritis (RA). In addition, preclinical studies including animal disease models have provided a substantial body of evidence implicating a causal contribution of systemic inflammation to cachexia. The presence of inflammatory cytokines can affect skeletal muscle through several direct mechanisms, relying on activation of the corresponding receptor expressed by muscle, and resulting in inhibition of muscle protein synthesis (MPS), elevation of catabolic activity through the ubiquitin-proteasomal system (UPS) and autophagy, and impairment of myogenesis. Additionally, systemic inflammatory mediators indirectly contribute to muscle wasting through dysregulation of tissue and organ systems, including GCs via the hypothalamus-pituitary-adrenal (HPA) axis, the digestive system leading to anorexia-cachexia, and alterations in liver and adipocyte behavior, which subsequently impact on muscle. Finally, myokines secreted by skeletal muscle itself in response to inflammation have been implicated as autocrine and endocrine mediators of cachexia, as well as potential modulators of this debilitating condition. While inflammation has been shown to play a pivotal role in cachexia development, further understanding how these cytokines contribute to disease progression is required to reveal biomarkers or diagnostic tools to help identify at risk patients, or enable the design of targeted therapies to prevent or delay the progression of cachexia.

Heal the heart through gut (hormone) ghrelin: a potential player to combat heart failure

Ghrelin, a small peptide hormone (28 aa), secreted mainly by X/A-like cells of gastric mucosa, is also locally produced in cardiomyocytes. Being an orexigenic factor (appetite stimulant), it promotes release of growth hormone (GH) and exerts diverse physiological functions, viz. regulation of energy balance, glucose, and/or fat metabolism for body weight maintenance. Interestingly, administration of exogenous ghrelin significantly improves cardiac functions in CVD patients as well as experimental animal models of heart failure. Ghrelin ameliorates pathophysiological condition of the heart in myocardial infarction, cardiac hypertrophy, fibrosis, cachexia, and ischemia reperfusion injury. This peptide also exerts significant impact at the level of vasculature leading to lowering high blood pressure and reversal of endothelial dysfunction and atherosclerosis. However, the molecular mechanism of actions elucidating the healing effects of ghrelin on the cardiovascular system is still a matter of conjecture. Some experimental data indicate its beneficial effects via complex cellular cross talks between autonomic nervous system and cardiovascular cells, some other suggest more direct receptor-mediated molecular actions via autophagy or ionotropic regulation and interfering with apoptotic and inflammatory pathways of cardiomyocytes and vascular endothelial cells. Here, in this review, we summarise available recent data to encourage more research to find the missing links of unknown ghrelin receptor-mediated pathways as we see ghrelin as a future novel therapy in cardiovascular protection.

Cardiac cachexia: the mandate to increase clinician awareness

PURPOSE OF REVIEW

Heart failure is a frequent problem in an ageing population, associated with high rates of morbidity and mortality. Today, it is important to not only treat heart failure itself but also the related comorbidities. Among them, cardiac cachexia is one of the major challenges. It is a complex multifactorial disease with a negative impact on quality of life and prognosis. Therefore, prevention, early recognition and treatment of cardiac cachexia is essential.

RECENT FINDINGS

Cardiac cachexia frequently presents with skeletal as well as heart muscle depletion. Imaging-based diagnostic techniques can help to identify patients with cardiac cachexia and muscle wasting. Several blood biomarkers are available to detect metabolic changes in cardiac cachexia.

SUMMARY

Several studies are currently ongoing to better comprehend the underlying pathophysiological mechanisms of cardiac cachexia and to find new treatments. It is essential to diagnose it as early as possible to initiate therapy.

The Additional Prognostic Value of Ghrelin for Mortality and Readmission in Elderly Patients with Acute Heart Failure

Purpose

To evaluate the prognostic value of ghrelin, a growth hormone-releasing peptide, for mortality and readmission in elderly patients with acute heart failure (AHF).

Patients and Methods

We measured plasma ghrelin and pro B-type natriuretic peptide (NT-proBNP) levels upon emergency admission in 241 prospectively recruited elderly AHF patients (61.0% men). The outcomes were all-cause mortality and/or readmission due to heart failure (HF). Multivariate Cox proportional hazards regression analyses were used to evaluate the prognostic value of ghrelin. Discrimination, calibration, and reclassification indices were compared between models, with or without ghrelin.

Results

During 1.2 years of follow-up, we observed 90 events (57 deaths and 33 readmissions due to HF). Plasma ghrelin levels were significantly elevated in elderly AHF patients, when compared to healthy control subjects (P < 0.001). Patients with events had significantly higher baseline ghrelin levels, when compared to those without (P < 0.001). Ghrelin levels were positively correlated with NT-proBNP levels and HF severity, whereas they were negatively correlated with nutritional status (all P < 0.05). Log transformed ghrelin levels were independently associated with AHF events (hazard ratio = 2.64, 95% confidence interval = 1.11–6.25, P = 0.028). The incorporation of ghrelin into the reference model, or reference with the NT-proBNP model, both improved C-statistics (from 0.742–0.780 and 0.836–0.857; P = 0.074 and 0.044, respectively), resulting in an improvement in net reclassification index (14.42% and 10.45%, P = 0.020 and 0.025, respectively), and integrated discrimination index (5.64% and 3.60%, both P < 0.001). Patients who displayed the above NT-proBNP and ghrelin median levels had a markedly higher risk of AHF adverse events (P < 0.001).

Conclusion

Plasma ghrelin is an independent predictor of adverse events in elderly AHF patients. Ghrelin may provide additional value to clinical parameters or NT-proBNP for prognostic risk stratification in AHF.

Anabolism to Catabolism: Serologic Clues to Nutritional Status in Heart Failure

PURPOSE OF REVIEW

Malnutrition, sarcopenia, and cachexia are areas of increasing interest in the management of patients with heart failure (HF). This review aims to examine the serological markers useful in guiding the physician in identification of these patients.

RECENT FINDINGS

Traditional nutritional biomarkers including albumin/prealbumin, iron, and vitamin D deficiencies predict poor prognosis in malnutrition and HF. Novel biomarkers including ghrelin, myostatin, C-terminal agrin fragment, and adiponectin have been identified as possible substrates and/or therapeutic targets in cardiac patients with sarcopenia and cachexia, though clinical trial data is limited to date. Increased focus on nutritional deficiency syndromes in heart failure has led to the use of established markers of malnutrition as well as the identification of novel biomarkers in the management of these patients, though to date, their usage has been confined to the academic domain and further research is required to establish their role in the clinical setting.

Involvement of the GHSR in the developmental programming and metabolic disturbances induced by maternal undernutrition

The mismatch between maternal undernutrition and adequate nutrition after birth increases the risk of developing metabolic diseases. We aimed to investigate whether the hyperghrelinemia during maternal undernourishment rewires the hypothalamic development of the offspring and contributes to the conversion to an obese phenotype when fed a high-fat diet (HFD). Pregnant C57BL/6 J, wild type (WT) and ghrelin receptor (GHSR)^-/- mice were assigned to either a normal nourished (NN) group, or an undernutrition (UN) (30% food restricted) group. All pups were fostered by NN Swiss mice. After weaning, pups were fed a normal diet, followed by a HFD from week 9. Plasma ghrelin levels peaked at postnatal day 15 (P15) in both C57BL/6 J UN and NN pups. Hypothalamic Ghsr mRNA expression was upregulated at P15 in UN pups compared to NN pups and inhibited agouti-related peptide (AgRP) projections. Adequate lactation increased body weight of UN WT but not of GHSR^-/- pups compared to NN littermates. After weaning with a HFD, body weight and food intake was higher in WT UN pups but lower in GHSR^-/- UN pups than in NN controls. The GHSR prevented a decrease in ambulatory activity and oxygen consumption in UN offspring during ad libitum feeding. Maternal undernutrition triggers developmental changes in the hypothalamus in utero which were further affected by adequate feeding after birth during the postnatal period by affecting GHSR signaling. The GHSR contributes to the hyperphagia and the increase in body weight when maternal undernutrition is followed by an obesity prone life environment.

Effect of grelin on TRX expression in chronic heart failure tissue: A protocol of systematic review and meta-analysis

BACKGROUND

The aim of this study is to explore the effect of grelin on TRX expression (TRXE) in chronic heart failure tissue (CHFT).

METHODS

We will search electronic databases from inception to the March 1, 2020 in MEDLINE, EMBASE, Cochrane Library, CINAHL, PEDro, the Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. We will not apply any limitations to the language and publication status. Any randomized controlled trials (RCTs) that studied the effect of grelin on TRXE in CHFT will be included. Study quality will be checked by Cochrane risk of bias and evidence quality will be appraised by Grading of Recommendations Assessment Development and Evaluation. All extracted data will be analyzed by RevMan 5.3 Software.

RESULTS

This study will summarize the present RCTs to assess the effect of grelin on TRXE in CHFT.

CONCLUSION

The results of this study will provide conclusive evidence of the effect of grelin on TRXE in CHFT.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202040078.

Inflammatory cytokines, appetite-regulating hormones, and energy metabolism in patients with gastrointestinal cancer

This study investigated energy metabolism and its association with inflammatory cytokines and appetite- regulating hormones in patients with gastrointestinal cancer. Subjects were inpatients scheduled to undergo therapeutic intervention for diagnosed gastrointestinal cancer. Nutritional status on admission was assessed based on anthropometric measurements, nutrition screening results, food intake rate (energy intake/energy provided in hospital food), and biochemical test results. Fat-free mass (FFM) was measured using the bioelectrical impedance analysis. Resting energy expenditure (REE) and respiratory quotient were measured with indirect calorimetry, and basal energy expenditure (BEE) was calculated using the Harris-Benedict equation. A total 51 patients with gastrointestinal cancer were enrolled (17 with esophageal cancer, 15 with gastric cancer, and 19 with colorectal cancer); 16 had stage I disease, 11 had stage II, 13 had stage III, and 11 had stage IV. The levels of inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α increased significantly with cancer stage progression (P<0.001; Jonckheere-Terpstra trend test). The REE/body weight and the REE/FFM tended to increase with cancer stage progression (P=0.064 and P=0.053, respectively; Jonckheere-Terpstra trend test). FFM showed a significant negative correlation with the level of TNF-α (P=0.008; Spearman's correlation coefficient). Also, food intake rate showed a significant negative correlation with levels of IL-6 and TNF-α (P<0.001). The level of active ghrelin was positively correlated with that of IL-6 and energy metabolism (P=0.004 and 0.016, respectively) and negatively correlated with food intake rate (P=0.035), which suggests a state of ghrelin resistance. In conclusion, this study confirmed increases in the levels of inflammatory cytokines with the progression of gastrointestinal cancer and suggested the possible association of such increases with decreased FFM and the increased energy metabolism. However, the increased levels of active ghrelin failed to compensate for cachexia in cancer patients.

Cardiac cachexia

Cachexia is a multifactorial disease characterized by a pathologic shift of metabolism towards a more catabolic state. It frequently occurs in patients with chronic diseases such as chronic heart failure and is especially common in the elderly. In patients at risk, cardiac cachexia is found in about 10% of heart failure patients. The negative impact of cardiac cachexia on mortality, morbidity, and quality of life demonstrates the urgent need to find new effective therapies against cardiac cachexia. Furthermore, exercise training and nutritional support can help patients with cardiac cachexia. Despite ongoing efforts to find new therapies for cachexia treatment, also new preventive strategies are needed.

Prognostic Significance of Serum Cholinesterase Level in Patients With Acute Decompensated Heart Failure With Preserved Ejection Fraction: Insights From the PURSUIT-HFpEF Registry

Background

Malnutrition is one of the most important comorbidities in patients with heart failure with preserved ejection fraction. We recently reported the prognostic significance of serum cholinesterase level and superior predictive power of cholinesterase level to other objective nutritional indices such as the controlling nutritional status score, prognostic nutritional index, and geriatric nutritional risk index in patients with acute decompensated heart failure. The aim of this study was to clarify the prognostic role of cholinesterase in patients with heart failure with preserved ejection fraction/acute decompensated heart failure and investigate incremental cholinesterase value.

Methods and Results

We prospectively studied 274 consecutive patients from the PURSUIT‐HFpEF (Prospective Multicenter Observational Study of Patients with Heart Failure With Preserved Ejection Fraction) study. During a follow‐up period of 1.2±0.6 years, 56 patients reached the composite end points (cardiovascular death and readmission for worsening heart failure). In the multivariable Cox analysis, cholinesterase level was significantly associated with the composite end points after adjustment for major confounders. A Kaplan–Meier analysis revealed that patients with low cholinesterase levels (stratified by tertile) had significantly greater risk of reaching the composite end points than those with middle or high cholinesterase levels (P=0.0025). Cholinesterase level showed the best C‐statistics (0.703) for prediction of the composite end points among the objective nutritional indices. C‐statistics of the Meta‐Analysis Global Group in Chronic Heart Failure (MAGGIC) risk score for prediction of the composite end points were improved when cholinesterase level was added (C‐statistics, from 0.601 to 0.705; P=0.0408).

Conclusions

Cholinesterase was a useful prognostic marker for prediction of adverse outcome in patients with heart failure with preserved ejection fraction/acute decompensated heart failure.

Promotion of myotube differentiation and attenuation of muscle atrophy in murine C2C12 myoblast cells treated with teaghrelin

This study aimed to investigate the effects of teaghrelin, an active ingredient of Chin-shin oolong tea, on murine C2C12 myoblast cells. Under high serum conditions, teaghrelin inhibited C2C12 cell proliferation, indicating a cell cycle arrest and cessation of proliferative progression. Teaghrelin promoted pro-differentiation of C2C12 cells as evidenced by a progressively elongated morphology, as well as the induction of muscle specific myogenin, myosin heavy chain (MHC), and MyoD. The formation of multinucleated myotubes, and the increase of MHC-positive immunoreactivity within the myotubes, further reflected a complete differentiation and maturation of the contractile skeletal muscle cells induced by teaghrelin. Like ghrelin, teaghrelin attenuated dexamethasone-decreased myotube diameter, indicating its protective effects against skeletal muscle atrophy. Additionally, the expressions of Atrogin-1 and MuRF-1 ubiquitin E3 ligase were reduced. In conclusion, the results highlight a possibility of developing teaghrelin as a functional food for the prevention or therapeutic treatment of disease-associated skeletal muscle atrophy.

Placental extract suppresses cardiac hypertrophy and fibrosis in an angiotensin II-induced cachexia model in mice

Cachexia is an intractable metabolic disorder that causes extreme weight loss. It is a symptom of many chronic diseases, including cancer, liver failure, congestive heart failure and chronic kidney disease, and there is as yet no effective treatment. While the mechanisms underlying cachexia are complex, it is often accompanied by elevated angiotensin II (Ang II). Human placental extract (HPE) is a source of numerous biologically active molecules and has been used clinically to treat chronic hepatitis, liver cirrhosis and other chronic diseases. Here, we investigated the effects of HPE in an Ang II-induced cachexia model in mice. HPE treatment preserved both fat mass and lean body mass and suppressed weight loss in the cachexia model, though food intake was unaffected. Ang II infusion also caused cardiac hypertrophy and fibrosis. HPE suppressed these effects as well as Ang II-induced cardiac expression of genes related to heart failure and cardiac remodeling. HPE also reversed Ang II-induced downregulation of mitochondria-related molecules and suppressed cardiac inflammation and oxidative stress. HPE administration may thus be an effective approach to the treatment of cachexia, cardiac hypertrophy and fibrosis.

The influence of skeletal muscle on appetite regulation

INTRODUCTION

Fat-free mass, of which skeletal muscle is amajor component, correlates positively with energy intake at energy balance. This is due to the effects of metabolically active tissue on energy expenditure which in itself appears to signal to the brain adrive to eat to ensure cellular energy homeostasis. The mechanisms responsible for this drive to eat are unknown but are likely to be related to energy utilization. Here muscle imparts an indirect influence on hunger. The drive to eat is also enhanced after muscle loss secondary to intentional weight loss. The evidence suggests loss of both fat mass and skeletal muscle mass directly influences the trajectory and magnitude of weight regain highlighting their potential role in long-termappetite control. The mechanisms responsible for the potential direct drive to eat stemming from muscle loss are unknown.

AREAS COVERED

The literature pertaining to muscle and appetite at energy balance and after weight loss was examined. Aliterature search was conducted to identify studies related to appetite, muscle, exercise, and weight loss.

EXPERT OPINION

Understanding the mechanisms which link energy expenditure and muscle loss to hunger has the potential to positively impact both the prevention and the treatment of obesity.

Ghrelin prevents cardiac cell apoptosis during cardiac remodelling post experimentally induced myocardial infarction in rats via activation of Raf-MEK1/2-ERK1/2 signalling

CONTEXT

Mechanisms by which ghrelin affords its cardioprotection in mammals remained unclear.

OBJECTIVE

To examine if ghrelin confers cardio-protection during cardiac remodelling post-MI by modulating the RAF-1-MEK1/2-ERK1/2 signalling pathway.

MATERIALS AND METHODS

Rats were divided into control, sham, sham + ghrelin, myocardial infarction (MI), and MI + ghrelin groups. Ghrelin (100 µg/kg) was administered for 21 days, starting one-day post-MI.

RESULTS

Ghrelin enhanced cardiac contractility and the activities of antioxidant enzymes, lowered serum levels of enzyme markers of cardiac dysfunction, and lowered inflammatory mediator levels. Ghrelin increased levels of phospho-Raf-1 (Ser³³⁸), phospho-MEK1/2 (Ser^217/221), phospho-ERK1/2 (Thr²⁰²/Tyr²⁰⁴), and of their downstream target p-BAD (Ser¹¹²) and inhibited the cleavage of caspase-3. Concomitantly, ghrelin prevented the increases in the levels of fibrotic markers, including α-smooth muscle actin (α-SMA), metalloproteinase-9 (MPP-9), and type III collagen.

CONCLUSION

Post-MI in rats, ghrelin stimulated Raf-1-MEK1/2-ERK1/2-BAD signalling in the LV infarct areas, accounting for its anti-apoptotic effect, enhancing cardiac function, and inhibiting cardiac fibrosis during cardiac remodelling.

Effects of IBDV infection on expression of ghrelin and ghrelin-related genes in chicken

Ghrelin is a peptide hormone that plays a modulatory role in the immune system. Studies have demonstrated that mammal ghrelin level is influenced by pathological status. However, it has not been reported whether chicken ghrelin level changes during pathogen infection. This study was designed to investigate changes of ghrelin levels in chickens infected with infectious bursal disease virus (IBDV) and to explore the relationship between ghrelin changes and bursal damage, and inflammatory cells infiltration induced by IBDV. The results showed that (1) plasma ghrelin concentration increased after IBDV infection. It reached a peak at 10443.6 ± 2612.9 pg/mL on 2 dpi, which was about 100-fold as high as that of the control. Then it decreased sharply on 3 dpi, which was only 31.7% as that of 2 dpi, and remained stable until 5 dpi. Meanwhile, ghrelin and ghrelin-related gene, ghrelin-o-acyltransferase (GOAT), and growth hormone secretagogue receptor (GHSR) mRNA expression levels in bursa were also increased after IBDV infection, and reached the peak on 2 dpi at 149, 28.8, and 117.2-fold higher than that of the control, respectively. Then they decreased and remained at a higher status. Correlation analysis showed that plasma ghrelin concentration and ghrelin, GOAT, and GHSR mRNA expressions in bursa were strongly associated with IBDV VP2 mRNA expression in bursa. (2) The damage of bursa was the most severe on 5 dpi with a histopathological score of 12. It had no direct correlation with plasma ghrelin level and ghrelin, GOAT, and GHSR mRNA expressions in bursa. However, the number of inflammatory cells infiltrating into bursa, which was the highest on 2 and 3 dpi, showed significant a positive correlation with the ghrelin and GHSR mRNA expression. Presumably chicken ghrelin may function as an anti-inflammatory factor. In conclusion, IBDV infection upregulates the expression of ghrelin and ghrelin-related gene in chickens, and chicken ghrelin may play an important regulatory role during pathogen infection.

Physiological significance of ghrelin in the cardiovascular system

Ghrelin, a growth hormone-releasing peptide first discovered in rat stomach in 1999, is a ligand for the growth hormone secretagogue receptor. It participates in the regulation of diverse processes, including energy balance and body weight maintenance, and appears to be beneficial for the treatment of cardiovascular diseases. In animal models of chronic heart failure, ghrelin improves cardiac function and remodeling; these findings have been recapitulated in human patients. In other animal models, ghrelin effectively diminishes pulmonary hypertension. Moreover, ghrelin administration early after myocardial infarction decreased the frequency of fatal arrhythmia and improved survival rate. In ghrelin-deficient mice, endogenous ghrelin protects against fatal arrhythmia and promotes remodeling after myocardial infarction. Although the mechanisms underlying the effects of ghrelin on the cardiovascular system have not been fully elucidated, its beneficial effects appear to be mediated through regulation of the autonomic nervous system. Ghrelin is a promising therapeutic agent for cardiac diseases.

Ghrelin and the heart

Ghrelin, a growth hormone-releasing peptide that was first discovered in the stomach of rats in 1999, is an endogenous ligand of growth hormone secretagogue receptor. Ghrelin exerts its potent growth hormone-releasing and orexigenic activities by binding to specific receptors in the brain. Subsequent studies showed that ghrelin participates in the regulation of diverse processes, including energy balance, body weight maintenance, and glucose and fat metabolism, and demonstrated that ghrelin is beneficial for treatment of cardiac diseases. In animal models of chronic heart failure, administration of ghrelin improves cardiac function and remodeling, and these findings were recapitulated in human patients with heart failure. Also in animal models, ghrelin administration effectively diminishes pulmonary hypertension induced by monocrotaline or chronic hypoxia. In addition, repeated administration of ghrelin to cachectic chronic obstructive pulmonary disease patients has positive effects on body composition, including amelioration of muscle wasting, improvement of functional capacity, and sympathetic activity. Moreover, administration of ghrelin early after myocardial infarction decreases the frequency of fatal arrhythmia and improved the survival rate. In ghrelin-deficient mice, both exogenous and endogenous ghrelin protects against fatal arrhythmia and promotes remodeling after myocardial infarction. Although the mechanisms underlying the effects of ghrelin on the cardiovascular system have not been fully elucidated, some evidence suggests that its beneficial effects are mediated through both direct actions on cardiovascular cells and regulation of autonomic nervous system activity. Therefore, ghrelin is a promising novel therapeutic agent for cardiac disease.

Ghrelin Receptor Agonist Rescues Excess Neonatal Mortality in a Prader-Willi Syndrome Mouse Model

In the current study, we sought to determine the significance of the ghrelin system in Prader-Willi Syndrome (PWS). PWS is characterized by hypotonia and difficulty feeding in neonates and hyperphagia and obesity beginning later in childhood. Other features include low GH, neonatal hypoglycemia, hypogonadism, and accelerated mortality. Although the hyperphagia and obesity in PWS have been attributed to elevated levels of the orexigenic hormone ghrelin, this link has never been firmly established, nor have ghrelin's potentially protective actions to increase GH secretion, blood glucose, and survival been investigated in a PWS context. In the current study, we show that placing Snord116del mice modeling PWS on ghrelin-deficient or ghrelin receptor [GH secretagogue receptor (GHSR)]-deficient backgrounds does not impact their characteristically reduced body weight, lower plasma IGF-1, delayed sexual maturation, or increased mortality in the period prior to weaning. However, blood glucose was further reduced in male Snord116del pups on a ghrelin-deficient background, and percentage body weight gain and percentage fat mass were further reduced in male Snord116del pups on a GHSR-deficient background. Strikingly, 2 weeks of daily administration of the GHSR agonist HM01 to Snord116del neonates markedly improved survival, resulting in a nearly complete rescue of the excess mortality owing to loss of the paternal Snord116 gene. These data support further exploration of the therapeutic potential of GHSR agonist administration in limiting PWS mortality, especially during the period characterized by failure to thrive.

Frailty in the End-Stage Lung Disease or Heart Failure Patient: Implications for the Perioperative Transplant Clinician

The syndrome of frailty for patients undergoing heart or lung transplantation has been a recent focus for perioperative clinicians because of its association with postoperative complications and poor outcomes. Patients with end-stage cardiac or pulmonary failure may be under consideration for heart or lung transplantation along with bridging therapies such as ventricular assist device implantation or venovenous extracorporeal membrane oxygenation, respectively. Early identification of frail patients in an attempt to modify the risk of postoperative morbidity and mortality has become an important area of study over the last decade. Many quantification tools and risk prediction models for frailty have been developed but have not been evaluated extensively or standardized in the cardiothoracic transplant candidate population. Heightened awareness of frailty, coupled with a better understanding of distinct cellular mechanisms and biomarkers apart from end-stage organ disease, may play an important role in potentially reversing frailty related to organ failure. Furthermore, the clinical management of these critically ill patients may be enhanced by waitlist and postoperative physical rehabilitation and nutritional optimization.

Identification and Pharmacological Profile of an Indane Based Series of Ghrelin Receptor Full Agonists

Cachexia and muscle wasting are very common among patients suffering from cancer, chronic obstructive pulmonary disease, and other chronic diseases. Ghrelin stimulates growth hormone secretion via the ghrelin receptor, which subsequently leads to increase of IGF-1 plasma levels. The activation of the GH/IGF-1 axis leads to an increase of muscle mass and functional capacity. Ghrelin further acts on inflammation, appetite, and adipogenesis and for this reason was considered an important target to address catabolic conditions. We report the synthesis and properties of an indane based series of ghrelin receptor full agonists; they have been shown to generate a sustained increase of IGF-1 levels in dog and have been thoroughly investigated with respect to their functional activity.

Neurohormonal Regulation of Appetite and its Relationship with Stress: A Mini Literature Review

Stress has long been known to affect eating behaviors in humans. Stress-induced hyperphagia is considered a potential cause for the development of obesity. Given the high prevalence of obesity and its association with other cardiovascular and metabolic disorders, the subject of stress-induced eating has become even more important. We reviewed data from past studies to further elucidate the relationship between stress, appetite regulation and eating patterns in humans. Even though it is difficult to say with certainty that a person exposed to stress will undereat or overeat, but certain assumptions can be made. Generally, acute stress results in decreased eating whereas chronic stress results in increased eating. Glucocorticoids, the effector molecules of the stress response, increase the tendency to consume high-calorie, palatable foods. Further studies that can link the biological markers of stress-response with the hormones and neurotransmitters of appetite regulation can broaden our understanding of the subject. These studies can provide a groundwork for the development of effective anti-obesity strategies.