scholarly journals Effects of Peroxisome Proliferator-Activated Receptor-α and -γ Agonists on 11β-Hydroxysteroid Dehydrogenase Type 1 in Subcutaneous Adipose Tissue in Men

2007 ◽  
Vol 92 (5) ◽  
pp. 1848-1856 ◽  
Author(s):  
Deborah J. Wake ◽  
Roland H. Stimson ◽  
Garry D. Tan ◽  
Natalie Z. M. Homer ◽  
Ruth Andrew ◽  
...  

Abstract Context: In animals, peroxisome proliferator-activated receptor-α (PPARα) and PPARγ agonists down-regulate 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) mRNA and activity in liver and adipose tissue, respectively, and PPARγ agonists reduce ACTH secretion from corticotrope cells. Objective: Our objective was to test whether PPAR agonists alter cortisol secretion and peripheral regeneration by 11β-HSD1 in humans and whether reduced cortisol action contributes to metabolic effects of PPARγ agonists. Design and Setting: Three randomized placebo-controlled crossover studies were conducted at a clinical research facility. Patients and Participants: Healthy men and patients with type 2 diabetes participated. Interventions, Outcome Measures, and Results: In nine healthy men, 7 d of PPARα agonist (fenofibrate) or PPARγ agonist (rosiglitazone) had no effect on cortisol secretion, hepatic cortisol generation after oral cortisone administration, or tracer kinetics during 9,11,12,12-[2H]4-cortisol infusion, although rosiglitazone marginally reduced cortisol generation in sc adipose tissue measured by in vivo microdialysis. In 12 healthy men, 4–5 wk of rosiglitazone increased insulin sensitivity during insulin infusion but did not change 11β-HSD1 mRNA or activity in sc adipose tissue, and insulin sensitization was unaffected by glucocorticoid blockade with a combination of metyrapone and RU38486. In 12 men with type 2 diabetes 12 wk of rosiglitazone reduced arteriovenous cortisone extraction across abdominal sc adipose tissue and reduced 11β-HSD1 mRNA in sc adipose tissue but increased plasma cortisol concentrations. Conclusions: Neither PPARα nor PPARγ agonists down-regulate 11β-HSD1 or cortisol secretion acutely in humans. The early insulin-sensitizing effect of rosiglitazone is not dependent on reducing intracellular glucocorticoid concentrations. Reduced adipose 11β-HSD1 expression and increased plasma cortisol during longer therapy with rosiglitazone probably reflect indirect effects, e.g. mediated by changes in body fat.

2006 ◽  
Vol 92 (2) ◽  
pp. 386-395 ◽  
Author(s):  
Arya M. Sharma ◽  
Bart Staels

Abstract Context: Adipose tissue is a metabolically dynamic organ, serving as a buffer to control fatty acid flux and a regulator of endocrine function. In obese subjects, and those with type 2 diabetes or the metabolic syndrome, adipose tissue function is altered (i.e. adipocytes display morphological differences alongside aberrant endocrine and metabolic function and low-grade inflammation). Evidence Acquisition: Articles on the role of peroxisome proliferator-activated receptor γ (PPARγ) in adipose tissue of healthy individuals and those with obesity, metabolic syndrome, or type 2 diabetes were sourced using MEDLINE (1990–2006). Evidence Synthesis: Articles were assessed to provide a comprehensive overview of how PPARγ-activating ligands improve adipose tissue function, and how this links to improvements in insulin resistance and the progression to type 2 diabetes and atherosclerosis. Conclusions: PPARγ is highly expressed in adipose tissue, where its activation with thiazolidinediones alters fat topography and adipocyte phenotype and up-regulates genes involved in fatty acid metabolism and triglyceride storage. Furthermore, PPARγ activation is associated with potentially beneficial effects on the expression and secretion of a range of factors, including adiponectin, resistin, IL-6, TNFα, plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, and angiotensinogen, as well as a reduction in plasma nonesterified fatty acid supply. The effects of PPARγ also extend to macrophages, where they suppress production of inflammatory mediators. As such, PPARγ activation appears to have a beneficial effect on the relationship between the macrophage and adipocyte that is distorted in obesity. Thus, PPARγ-activating ligands improve adipose tissue function and may have a role in preventing progression of insulin resistance to diabetes and endothelial dysfunction to atherosclerosis.


Author(s):  
Andrea G. Hohmann

The landmark paper discussed in this chapter, published by Calignano et al. in 1998, focuses on the control of pain initiation by endogenous cannabinoids. In the paper, analgesic lipid mediators are shown to be present in peripheral paw tissue where they control the ability of pain signals to ascend to the central nervous system (CNS). Anandamide acts through a peripheral mechanism to suppress inflammatory pain via cannabinoid type 1 receptors. Palmitoylethanolamine, subsequently identified as an endogenous ligand for peroxisome proliferator-activated receptor-α‎, produces peripheral antinociceptive effects via a mechanism similar to that for the cannabinoid type 2 receptor. These lipids do not serve redundant functions and, in combination, produce synergistic antinociceptive effects. These observations suggested that drug-development efforts targeting peripheral control of pain may elucidate improved pharmacotherapies that lack the unwanted CNS side effects of current treatments.


Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 425 ◽  
Author(s):  
Kenneth D’Souza ◽  
Angella Mercer ◽  
Hannah Mawhinney ◽  
Thomas Pulinilkunnil ◽  
Chibuike C. Udenigwe ◽  
...  

Deregulation of lipid metabolism and insulin function in muscle and adipose tissue are hallmarks of systemic insulin resistance, which can progress to type 2 diabetes. While previous studies suggested that milk proteins influence systemic glucose homeostasis and insulin function, it remains unclear whether bioactive peptides generated from whey alter lipid metabolism and its accumulation in muscle and adipose tissue. Therefore, we incubated murine 3T3-L1 preadipocytes and C2C12 myotubes with a whey peptide mixture produced through pepsin-pancreatin digestion, mimicking peptides generated in the gut from whey protein hydrolysis, and examined its effect on indicators of lipid metabolism and insulin sensitivity. Whey peptides, particularly those derived from bovine serum albumin (BSA), promoted 3T3-L1 adipocyte differentiation and triacylglycerol (TG) accumulation in accordance with peroxisome proliferator-activated receptor γ (PPARγ) upregulation. Whey/BSA peptides also increased lipolysis and mitochondrial fat oxidation in adipocytes, which was associated with the upregulation of peroxisome proliferator-activated receptor δ (PPARδ). In C2C12 myotubes, whey but not BSA peptides ameliorated palmitate-induced insulin resistance, which was associated with reduced inflammation and diacylglycerol accumulation, and increased sequestration of fatty acids in the TG pool. Taken together, our study suggests that whey peptides generated via pepsin-pancreatin digestion profoundly alter lipid metabolism and accumulation in adipocytes and skeletal myotubes.


2006 ◽  
Vol 154 (5) ◽  
pp. 613-621 ◽  
Author(s):  
Pedro Iglesias ◽  
Juan J Díez

Type 2 diabetes is a well recognised cause of chronic renal failure (CRF). Only few oral antidiabetic drugs can be used for treating type 2 diabetes in patients with CRF. Among them are repaglinide, a rapid-acting prandial insulin releaser, and peroxisome proliferator-activated receptor gamma (PPARγ) agonists, such as rosiglitazone and pioglitazone. These compounds are metabolised in the liver, therefore accumulation of the drug and the risk of severe and prolonged hypoglycaemia are minimised. PPARγ receptors are expressed in many tissues including the kidney. Recently, numerous healthful effects of PPARγ agonists on several aspects related to renal function have been increasingly reported. These drugs have shown to possess many advantageous anti-inflammatory, haemodynamic, vascular and metabolic effects. In the present paper we have reviewed the more recent experimental studies that evaluated these potential beneficial effects of PPARγ agonists on renal function and revised the results of their utilisation in patients with different degrees of renal impairment, in dialysis patients, and in patients with diabetes mellitus after kidney transplantation. Finally, tolerability and safety profile of PPARγ agonists in patients with reduced glomerular filtration rate are also analysed.


PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Sun ◽  
Zhanjun Jia ◽  
Gang Liu ◽  
Li Zhou ◽  
Mi Liu ◽  
...  

Evidence had shown the detrimental effect of prostaglandin (PG) E2 in diabetic nephropathy (DN) of STZ-induced type-1 diabetes but its role in the development of DN of type-2 diabetes remains uncertain. The present study was undertaken to investigate the regulation of PGE2 synthetic pathway and the interaction between peroxisome proliferator-activated receptor (PPAR)γand PGE2 synthesis in the kidneys of db/db mice. Strikingly, urinary PGE2 was remarkably elevated in db/db mice paralleled with the increased protein expressions of COX-2 and mPGES-1. In contrast, the protein expressions of COX-1, mPGES-2, cPGES, and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) were not altered. Following 1-week rosiglitazone (Rosi) therapy, urinary PGE2, but not other prostanoids, was reduced by 57% in parallel with significant reduction of mPGES-1 protein and EP4 mRNA expressions. By immunohistochemistry, mPGES-1 was significantly induced in the glomeruli of db/db mice, which was almost entirely abolished by Rosi. In line with the reduction of glomerular mPGES-1, the glomerular injury score showed a tendency of improvement after 1 week of Rosi therapy. Collectively, the present study demonstrated an inhibitory effect of PPARγactivation on renal mPGES-1/PGE2/EP4 pathway in type-2 diabetes and suggested that mPGES-1 may potentially serve as a therapeutic target for treating type-2 diabetes-associated DN.


2021 ◽  
pp. 1-31
Author(s):  
Long Cheng ◽  
Jingkang Wang ◽  
Yongcheng An ◽  
Hongyu Dai ◽  
Yuhui Duan ◽  
...  

Abstract The current epidemic of type 2 diabetes mellitus (T2DM) significantly affects human health worldwide. Activation of brown adipocytes and browning of white adipocytes are considered as a promising molecular target for T2DM treatment. Mulberry leaf, a traditional Chinese medicine, has been demonstrated to have multi-biological activities, including anti-diabetic and anti-inflammatory effects. Our experiment results showed that mulberry leaf significantly alleviated the disorder of glucose and lipid metabolism in T2DM rats including reducing body weight (BW) gain, Lee’s index, food intake, inguinal white adipose tissue (IWAT) accumulation, blood lipid fasting insulin level and fasting blood glucose level, increasing the ratios of brown adipose tissue (BAT) mass to BW, and improving insulin sensitivity and liver function. In addition, mulberry leaf induced browning of IWAT by enhancing the expressions of brown-mark genes as well as beige-specific genes, including uncoupling protein-1 (UCP1), peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), peroxisome proliferator-activated receptor alpha (PPARα), PRD1-BF-1-RIZ1 homologous domain containing protein 16 (PRDM16), cell death inducing DFFA like effector A (Cidea), CD137 and transmembrane protein 26 (TMEM26). Mulberry leaf also activated BAT by increasing the expressions of brown-mark genes including UCP1, PGC-1α, PPARα, PRDM16 and Cidea. Moreover, mulberry leaf enhanced the expression of nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) genes that are responsible for mitochondrial biogenesis in IWAT and BAT. Importantly, mulberry leaf also increased the expression of UCP1 and carnitine palmitoyl transferase 1 (CPT1) protein in both IWAT and BAT via a mechanism involving Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and PGC-1α pathway. In conclusion, our findings identify the role of mulberry leaf in inducing adipose browning, indicating that mulberry leaf may be used as a candidate browning agent for the treatment of T2DM.


2001 ◽  
Vol 276 (16) ◽  
pp. 12629-12635 ◽  
Author(s):  
Joel Berger ◽  
Michael Tanen ◽  
Alex Elbrecht ◽  
Anne Hermanowski-Vosatka ◽  
David E. Moller ◽  
...  

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