The authors discuss current concepts and controversies surrounding the complex influences of malnutrition on infection and immunity, and point to practical consequences of countermeasures in acute malnutrition.

/pdf/malnutrition-and-infection-complex-mechanisms-and-global-3ak2tsfc1j.pdf

Malnutrition and Infection: Complex Mechanisms and Global Impacts

The effects of ghrelin on inflammation and the immune system.

Ghrelin is an acylated peptidyl gastric hormone acting on the pituitary and hypothalamus to stimulate appetite, adiposity, and growth hormone release, through activation of growth hormone secretagogue receptor (GHSR)-1a receptor. Moreover, ghrelin features several activities such as inhibition of apoptosis, regulation of differentiation, and stimulation or inhibition of proliferation of several cell types. Ghrelin acylation is absolutely required for both GHSR-1a binding and its central endocrine activities. However, the unacylated ghrelin form, des-acyl ghrelin, which does not bind GHSR-1a and is devoid of any endocrine activity, is far more abundant than ghrelin in plasma, and it shares with ghrelin some of its cellular activities. In here we show that both ghrelin and des-acyl ghrelin stimulate proliferating C2C12 skeletal myoblasts to differentiate and to fuse into multinucleated myotubes in vitro through activation of p38. Consistently, both ghrelin and des-acyl ghrelin inhibit C2C12 proliferation in growth medium. Moreover, the ectopic expression of ghrelin in C2C12 enhances differentiation and fusion of these myoblasts in differentiation medium. Finally, we show that C2C12 cells do not express GHSR-1a, but they do contain a common high-affinity binding site recognized by both acylated and des-acylated ghrelin, suggesting that the described activities on C2C12 are likely mediated by this novel, yet unidentified receptor for both ghrelin forms.

/pdf/ghrelin-and-des-acyl-ghrelin-promote-differentiation-and-3pebmx06m4.pdf

Ghrelin and Des-Acyl Ghrelin Promote Differentiation and Fusion of C2C12 Skeletal Muscle Cells

Ghrelin is a gastric peptide hormone, discovered as being the endogenous ligand of growth hormone secretagogue receptor. Ghrelin is a 28 amino acid peptide presenting a unique n-octanoylation modification on its serine in position 3, catalyzed by ghrelin O-acyl transferase. Ghrelin is mainly produced by a subset of stomach cells and also by the hypothalamus, the pituitary, and other tissues. Transcriptional, translational, and posttranslational processes generate ghrelin and ghrelin-related peptides. Homo- and heterodimers of growth hormone secretagogue receptor, and as yet unidentified receptors, are assumed to mediate the biological effects of acyl ghrelin and desacyl ghrelin, respectively. Ghrelin exerts wide physiological actions throughout the body, including growth hormone secretion, appetite and food intake, gastric secretion and gastrointestinal motility, glucose homeostasis, cardiovascular functions, anti-inflammatory functions, reproductive functions, and bone formation. This review focuses on presenting the current understanding of ghrelin and growth hormone secretagogue receptor biology, as well as the main physiological effects of ghrelin.

/pdf/structure-and-physiological-actions-of-ghrelin-2da4specvs.pdf

Structure and Physiological Actions of Ghrelin

Objective: Ghrelin is the recently identified endogenous ligand for the ghrelin receptor GHS-R1a and known to regulate growth hormone secretion and appetite. Ghrelin also is a potent vasodilator and improves cardiac performance after systemic administration. Generally, the octanoyl modification on Ser 3 has been considered essential for biological activity. Recently however, cardiovascular actions of des-octanoyl ghrelin have been reported in rodents. Our aim was to investigate if ghrelin and ghrelin receptor protein are expressed within the human vasculature, to determine if des-octanoyl ghrelin, like ghrelin, is a vasodilator in human artery and to test the acute effect of ghrelin peptides on cardiac contractility. Methods: Distribution of ghrelin and ghrelin receptor was determined using standard immunocytochemistry and confocal microscopy. Ghrelin peptides were tested for vasodilator actions in human isolated arteries and their effect on cardiac contractility was investigated in human isolated paced atria. Results: Immunoreactive ghrelin was detected in endothelial cells of human arteries and veins where it localized to intracellular vesicles but not to the Weibel–Palade bodies of the regulated pathway, suggesting constitutive ghrelin production. Specific antisera detected ghrelin receptor on vascular smooth muscle cells and cardiomyocytes. Ghrelin (pD2=8.60 T0.1, Emax=55.8 T8.9, mean Tstandard error of the mean) and des-octanoyl ghrelin (pD2=8.8 T0.2, Emax=54.7 T5.3) showed comparable (P>0.05) endothelium independent vasodilator potency and efficacy in reversing endothelin-1 induced constriction in human artery. Neither ghrelin nor des-octanoyl ghrelin had effects on contractile force in paced atria. Conclusions: We show widespread expression of ghrelin and its cognate receptor in the human cardiovascular system with functional evidence suggesting a role for both ghrelin and the more abundant endogenous form des-octanoyl ghrelin in the paracrine regulation of vascular tone in man.

Functional and immunocytochemical evidence for a role of ghrelin and des-octanoyl ghrelin in the regulation of vascular tone in man

Effects of ghrelin on the proliferation and secretion of splenic T lymphocytes in mice.

Popular Tasks used by Researchers

How can I help with your research?

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

We encountered an error while loading the panel. Please try refreshing the page.

Something went wrong

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

Anyone with the link can view this chat. You can switch it back to private anytime.

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Wei Pang

Author Tools

Chat about Author

Papers

Effects of ghrelin on the proliferation and secretion of splenic T lymphocytes in mice.