scholarly journals Inflammatory Mediators and Insulin Resistance in Obesity: Role of Nuclear Receptor Signaling in Macrophages

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Lucía Fuentes ◽  
Tamás Rőszer ◽  
Mercedes Ricote

Visceral obesity is coupled to a general low-grade chronic inflammatory state characterized by macrophage activation and inflammatory cytokine production, leading to insulin resistance (IR). The balance between proinflammatory M1 and antiinflammatory M2 macrophage phenotypes within visceral adipose tissue appears to be crucially involved in the development of obesity-associated IR and consequent metabolic abnormalities. The ligand-dependent transcription factors peroxisome proliferator activated receptors (PPARs) have recently been implicated in the determination of the M1/M2 phenotype. Liver X receptors (LXRs), which form another subgroup of the nuclear receptor superfamily, are also important regulators of proinflammatory cytokine production in macrophages. Disregulation of macrophage-mediated inflammation by PPARs and LXRs therefore underlies the development of IR. This review summarizes the role of PPAR and LXR signaling in macrophages and current knowledge about the impact of these actions in the manifestation of IR and obesity comorbidities such as liver steatosis and diabetic osteopenia.

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Faloia Emanuela ◽  
Michetti Grazia ◽  
De Robertis Marco ◽  
Luconi Maria Paola ◽  
Furlani Giorgio ◽  
...  

The metabolic syndrome is a complex of clinical features leading to an increased risk for cardiovascular disease and type 2 diabetes mellitus in both sexes. Visceral obesity and insulin resistance are considered the main features determining the negative cardiovascular profile in metabolic syndrome. The aim of this paper is to highlight the central role of obesity in the development of a chronic low-grade inflammatory state that leads to insulin resistance, endothelial and microvascular dysfunctions. It is thought that the starting signal of this inflammation is overfeeding and the pathway origins in all the metabolic cells; the subsequent increase in cytokine production recruits immune cells in the extracellular environment inducing an overall systemic inflammation. This paper focuses on the molecular and cellular inflammatory mechanisms studied until now.


Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 145
Author(s):  
Julio Plaza-Díaz ◽  
Patricio Solis-Urra ◽  
Jerónimo Aragón-Vela ◽  
Fernando Rodríguez-Rodríguez ◽  
Jorge Olivares-Arancibia ◽  
...  

Non-alcoholic fatty liver disease (NAFLD) is an increasing cause of chronic liver illness associated with obesity and metabolic disorders, such as hypertension, dyslipidemia, or type 2 diabetes mellitus. A more severe type of NAFLD, non-alcoholic steatohepatitis (NASH), is considered an ongoing global health threat and dramatically increases the risks of cirrhosis, liver failure, and hepatocellular carcinoma. Several reports have demonstrated that liver steatosis is associated with the elevation of certain clinical and biochemical markers but with low predictive potential. In addition, current imaging methods are inaccurate and inadequate for quantification of liver steatosis and do not distinguish clearly between the microvesicular and the macrovesicular types. On the other hand, an unhealthy status usually presents an altered gut microbiota, associated with the loss of its functions. Indeed, NAFLD pathophysiology has been linked to lower microbial diversity and a weakened intestinal barrier, exposing the host to bacterial components and stimulating pathways of immune defense and inflammation via toll-like receptor signaling. Moreover, this activation of inflammation in hepatocytes induces progression from simple steatosis to NASH. In the present review, we aim to: (a) summarize studies on both human and animals addressed to determine the impact of alterations in gut microbiota in NASH; (b) evaluate the potential role of such alterations as biomarkers for prognosis and diagnosis of this disorder; and (c) discuss the involvement of microbiota in the current treatment for NAFLD/NASH (i.e., bariatric surgery, physical exercise and lifestyle, diet, probiotics and prebiotics, and fecal microbiota transplantation).


Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 909
Author(s):  
Krzysztof Kotowski ◽  
Jakub Rosik ◽  
Filip Machaj ◽  
Stanisław Supplitt ◽  
Daniel Wiczew ◽  
...  

Glycolysis is a crucial metabolic process in rapidly proliferating cells such as cancer cells. Phosphofructokinase-1 (PFK-1) is a key rate-limiting enzyme of glycolysis. Its efficiency is allosterically regulated by numerous substances occurring in the cytoplasm. However, the most potent regulator of PFK-1 is fructose-2,6-bisphosphate (F-2,6-BP), the level of which is strongly associated with 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase activity (PFK-2/FBPase-2, PFKFB). PFK-2/FBPase-2 is a bifunctional enzyme responsible for F-2,6-BP synthesis and degradation. Four isozymes of PFKFB (PFKFB1, PFKFB2, PFKFB3, and PFKFB4) have been identified. Alterations in the levels of all PFK-2/FBPase-2 isozymes have been reported in different diseases. However, most recent studies have focused on an increased expression of PFKFB3 and PFKFB4 in cancer tissues and their role in carcinogenesis. In this review, we summarize our current knowledge on all PFKFB genes and protein structures, and emphasize important differences between the isoenzymes, which likely affect their kinase/phosphatase activities. The main focus is on the latest reports in this field of cancer research, and in particular the impact of PFKFB3 and PFKFB4 on tumor progression, metastasis, angiogenesis, and autophagy. We also present the most recent achievements in the development of new drugs targeting these isozymes. Finally, we discuss potential combination therapies using PFKFB3 inhibitors, which may represent important future cancer treatment options.


Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5157-5164 ◽  
Author(s):  
Thomas A. Bowman ◽  
Sadeesh K. Ramakrishnan ◽  
Meenakshi Kaw ◽  
Sang Jun Lee ◽  
Payal R. Patel ◽  
...  

Rats selectively bred for low aerobic running capacity exhibit the metabolic syndrome, including hyperinsulinemia, insulin resistance, visceral obesity, and dyslipidemia. They also exhibit features of nonalcoholic steatohepatitis, including chicken-wire fibrosis, inflammation, and oxidative stress. Hyperinsulinemia in these rats is associated with impaired hepatic insulin clearance. The current studies aimed to determine whether these metabolic abnormalities could be reversed by caloric restriction (CR). CR by 30% over a period of 2–3 months improved insulin clearance in parallel to inducing the protein content and activation of the carcinoembryonic antigen-related cell adhesion molecule 1, a main player in hepatic insulin extraction. It also reduced glucose and insulin intolerance and serum and tissue (liver and muscle) triglyceride levels. Additionally, CR reversed inflammation, oxidative stress, and fibrosis in liver. The data support a significant role of CR in the normalization of insulin and lipid metabolism in liver.


Author(s):  
Charmaine S. Tam ◽  
Leanne M. Redman

AbstractObesity is characterized by a state of chronic low-grade inflammation due to increased immune cells, specifically infiltrated macrophages into adipose tissue, which in turn secrete a range of proinflammatory mediators. This nonselective low-grade inflammation of adipose tissue is systemic in nature and can impair insulin signaling pathways, thus, increasing the risk of developing insulin resistance and type 2 diabetes. The aim of this review is to provide an update on clinical studies examining the role of adipose tissue in the development of obesity-associated complications in humans. We will discuss adipose tissue inflammation during different scenarios of energy imbalance and metabolic dysfunction including obesity and overfeeding, weight loss by calorie restriction or bariatric surgery, and conditions of insulin resistance (diabetes, polycystic ovarian syndrome).


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Maja Dorota Wojciechowska

Purpose The purpose of the paper is to present the latest scholarly trends in the field of social capital in libraries, to review research concepts published by LIS professionals and to suggest further research possibilities in this area. Design/methodology/approach This paper presents a review and critical analysis of literature associated with research on social capital in libraries to highlight its importance for the development of LIS and its impact on the functioning of environments linked with various types of libraries. The goal of literature analysis was to determine the current condition of research on social capital in libraries. The main trends were identified and the need for further qualitative analyses, which are missing at the moment, was confirmed. Findings It was determined that, so far, LIS professionals have focussed mainly on the role of municipal libraries in developing social capital, the problem of building trust, especially in immigrant circles and the impact of libraries on promoting a civil society. Academic libraries, rural libraries, organisational capital in libraries and individual social capital of librarians were a much less frequent subject of research. The role of libraries in developing social capital in educational (primary and secondary education) and professional (non-university professionals) circles is practically non-existent in research, and it will require in-depth studies and analyses in the coming years. Originality/value This paper constitutes a synthetic review of the latest research concepts concerning social capital in libraries. It identifies the most important research trends and areas that so far have not been explored and suggests research methods to help LIS professionals design future research in this area more effectively.


2021 ◽  
Vol 162 (33) ◽  
pp. 1318-1327
Author(s):  
Tamás Halmos ◽  
Ilona Suba

Összefoglaló. Az emberek a lehető leghosszabb ideig akarnak élni, jó egészségben. Ha kiküszöbölnénk a kedvezőtlen külső körülményeket, a várható élettartam meghaladhatná a 100 évet. A 20. és 21. században a jóléti társadalmakban a várható élettartam jelentősen megnőtt, így Magyarországon is. Az áttekintett irodalom alapján megvizsgáltuk, hogy a genetika és az öröklődés mellett milyen endokrinológiai és metabolikus tényezők játszanak szerepet az élet meghosszabbításában. Megvizsgáltunk minden endogén tényezőt, amely pozitívan vagy negatívan befolyásolhatja az életkorral összefüggő betegségeket (Alzheimer-kór, szív- és érrendszeri betegségek, rák) és az élettartamot. Kiemeltük a hyperinsulinaemia, az inzulinrezisztencia, a metabolikus szindróma öregedést gyorsító hatását, az inzulinszerű növekedési hormon-1 ellentmondásos szerepét, valamint az élet meghosszabbításában részt vevő, újabban felfedezett peptideket, mint a klotho és a humanin. Ismertettük a mitochondriumok szerepét az élettartam meghatározásában, bemutattuk a mitohormesis folyamatát és annak stresszvédő funkcióját. Bemutattuk a rapamicin célszervét, az mTOR-t, amelynek gátlása meghosszabbítja az élettartamot, valamint a szirtuinokat. Kitértünk az autophagia folyamatára, és ismertettük a szenolitikumok szerepét az öregedésben. Az időskori autoimmunitás csökkenése hozzájárul az élettartam rövidüléséhez, utaltunk a thymus koordináló szerepére. Kiemeltük a bélmikrobiom fontos szerepét az élettartam szabályozásában. Hivatkoztunk a „centenáriusok” megfigyeléséből nyert humánadatokra. Megvizsgáltuk, milyen beavatkozási lehetőségek állnak rendelkezésre az egészségben tölthető élettartam meghosszabbításához. Az életmódbeli lehetőségek közül kiemeltük a kalóriabevitel-csökkentés és a testmozgás jótékony szerepét. Megvizsgáltuk egyes gyógyszerek feltételezett hatásait. Ezek közé tartozik a metformin, az akarbóz, a rezveratrol. E gyógyszerek mindegyikének hatása hasonló a kalóriamegszorításéhoz. Nincs olyan „csodaszer”, amely igazoltan meghosszabbítja az élettartamot emberben. Egyes géneknek és génmutációknak jótékony hatásuk van, de ezt környezeti tényezők, betegségek, balesetek és más külső ártalmak módosíthatják. Kiemeljük az elhízás, az alacsony fokozatú gyulladás és az inzulinrezisztencia öregedésre gyakorolt gyorsító hatását. A metabolikus szindróma elterjedtsége miatt ez jelentős népegészségügyi kockázatot jelent. Az inzulin, a növekedési hormon és az inzulinszerű növekedési faktorok hatásainak értékelése továbbra is ellentmondásos. Az egészséges, szellemileg és fizikailag aktív életmód, a kalóriacsökkentés mindenképpen előnyös. Az életet meghosszabbító szerek értékelése még vitatott. Orv Hetil. 2021; 162(33): 1318–1327. Summary. People want to live as long as possible in good health. If we eliminate the unfavorable external conditions, the life expectancy could exceed 100 years. In the 20th and 21th centuries, life expectancy in welfare societies increased significantly, including in Hungary. Based on the reviewed literature, we examined what endocrinological and metabolic factors play a role in prolonging life in addition to genetics and inheritance. We examined all endogenous factors that can positively or negatively affect age-related diseases (Alzheimer’s disease, cardiovascular disease, cancer) and longevity. We highlighted the aging effects of hyperinsulinemia, insulin resistance, metabolic syndrome, the controversial role of insulin-like growth factor-1, and more recently discovered peptides involved in prolonging lifespan, such as klotho and humanin. We described the role of mitochondria in determining longevity, we demonstrated the process of mitohormesis and its stress-protective function. We presented the target organ of rapamycin, mTOR, the inhibition of which prolongs lifespan, as well as sirtuins. We covered the process of autophagy and described the role of senolytics in aging. The decrease in autoimmunity in old age contributes to the shortening of life expectancy, we referred to the coordinating role of the thymus. We highlighted the important role of intestinal microbiome in the regulation of longevity. We referred to human data obtained from observations on “centenarians”. We examined what intervention options are available to prolong healthy life expectancy. Among the lifestyle options, we highlighted the beneficial role of calorie reduction and exercise. We examined the putative beneficial effects of some drugs. These include metformin, acarbose, resveratrol. The effect of each of these drugs is similar to calorie restriction. There is no “miracle cure” that has been shown to prolong life-span in humans. Some genes and gene mutations have beneficial effects, but this can be modified by environmental factors, diseases, accidents, and other external harms. We highlight the accelerating effects of obesity, low-grade inflammation, and insulin resistance on aging. Due to the prevalence of metabolic syndrome, this poses a significant risk to public health. The assessment of the effects of insulin, growth hormone, and insulin-like growth factors remains controversial. A healthy, mentally and physically active lifestyle, calorie reduction is definitely beneficial. The evaluation of life-prolonging agents is still controversial. Orv Hetil. 2021; 162(33): 1318–1327.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shireen Mohammad ◽  
Sura Al Zoubi ◽  
Debora Collotta ◽  
Nadine Krieg ◽  
Bianka Wissuwa ◽  
...  

Metabolic endotoxemia has been suggested to play a role in the pathophysiology of metaflammation, insulin-resistance and ultimately type-2 diabetes mellitus (T2DM). The role of endogenous antimicrobial peptides (AMPs), such as the cathelicidin LL-37, in T2DM is unknown. We report here for the first time that patients with T2DM compared to healthy volunteers have elevated plasma levels of LL-37. In a reverse-translational approach, we have investigated the effects of the AMP, peptide 19-2.5, in a murine model of high-fat diet (HFD)-induced insulin-resistance, steatohepatitis and T2DM. HFD-fed mice for 12 weeks caused obesity, an impairment in glycemic regulations, hypercholesterolemia, microalbuminuria and steatohepatitis, all of which were attenuated by Peptide 19-2.5. The liver steatosis caused by feeding mice a HFD resulted in the activation of nuclear factor kappa light chain enhancer of activated B cells (NF-ĸB) (phosphorylation of inhibitor of kappa beta kinase (IKK)α/β, IκBα, translocation of p65 to the nucleus), expression of NF-ĸB-dependent protein inducible nitric oxide synthase (iNOS) and activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome, all of which were reduced by Peptide 19-2.5. Feeding mice, a HFD also resulted in an enhanced expression of the lipid scavenger receptor cluster of differentiation 36 (CD36) secondary to activation of extracellular signal-regulated kinases (ERK)1/2, both of which were abolished by Peptide 19-2.5. Taken together, these results demonstrate that the AMP, Peptide 19-2.5 reduces insulin-resistance, steatohepatitis and proteinuria. These effects are, at least in part, due to prevention of the expression of CD36 and may provide further evidence for a role of metabolic endotoxemia in the pathogenesis of metaflammation and ultimately T2DM. The observed increase in the levels of the endogenous AMP LL-37 in patients with T2DM may serve to limit the severity of the disease.


Reproduction ◽  
2021 ◽  
Vol 161 (1) ◽  
pp. F1-F17
Author(s):  
Rocío Martínez-Aguilar ◽  
Lucy E Kershaw ◽  
Jane J Reavey ◽  
Hilary O D Critchley ◽  
Jacqueline A Maybin

The endometrium is a multicellular tissue that is exquisitely responsive to the ovarian hormones. The local mechanisms of endometrial regulation to ensure optimal function are less well characterised. Transient physiological hypoxia has been proposed as a critical regulator of endometrial function. Herein, we review the literature on hypoxia in the non-pregnant endometrium. We discuss the pros and cons of animal models, human laboratory studies and novel in vivo imaging for the study of endometrial hypoxia. These research tools provide mounting evidence of a transient hypoxic episode in the menstrual endometrium and suggest that endometrial hypoxia may be present at the time of implantation. This local hypoxia may modify the inflammatory environment, influence vascular remodelling and modulate endometrial proliferation to optimise endometrial function. Finally, we review current knowledge of the impact of this hypoxia on endometrial pathologies, with a focus on abnormal uterine bleeding. Throughout the manuscript areas for future research are highlighted with the aim of concentrating research efforts to maximise future benefits for women and society.


2010 ◽  
Vol 7 (4) ◽  
pp. 8-11 ◽  
Author(s):  
N A Petunina ◽  
N E Al'tshuler ◽  
N G Rakova ◽  
L V Trukhina

The review presents a recent data from the literature on the physiologic and pathophysiologic role of adipose tissue hormones (adiponectin, resistin, leptin). The article details the role of adipocytokines in atherogenesis. It also presents the results of studies depicting the relationship between subclinical hypothyroidism, lipid metabolism and insulin resistance as well as the impact of thyroid dysfunction upon the secretion of adipocytokines.


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