Fenofibrate reduces serum retinol-binding protein-4 by suppressing its expression in adipose tissue

Retinol binding protein 4 antagonists and protein synthesis inhibitors: Potential for therapeutic development

Retinol-binding protein 4 (RBP4) is a serum protein that transports Vitamin A. RBP4 is correlated with numerous diseases and metabolic syndromes, including insulin resistance in type 2 diabetes, cardiovascular diseases, obesity, and macular degeneration. Recently, RBP4 antagonists and protein synthesis inhibitors are under development to regulate the effect of RBP4. Several RBP4 antagonists, especially BPN-14136, have demonstrated promising safety profiles and potential therapeutic benefits in animal studies. Two RBP4 antagonists, specifically tinlarebant (Belite Bio) and STG-001 (Stargazer) are currently undergoing clinical trials. Some antidiabetic drugs and nutraceuticals have been reported to reduce RBP4 expression, but more clinical data is needed to evaluate their therapeutical benefits. As regulating RBP4 levels or its activities would benefit a wide range of patients, further research is highly recommended to develop clinically useful RBP4 antagonists or protein synthesis inhibitors.

Transcriptional regulation of retinol binding protein 4 by Interleukin-6 via peroxisome proliferator-activated receptor α and CCAAT/Enhancer binding proteins

Interleukin-6 (IL-6) is a major mediator of the acute phase response (APR) that regulates the transcription of acute phase proteins (APPs) in the liver. During APR, the plasma levels of negative APPs including retinol binding protein 4 (RBP4) are reduced. Activation of the IL-6 receptor and subsequent signaling pathways leads to the activation of transcription factors, including peroxisome proliferator-activated receptor alpha (PPARα) and CCAAT/enhancer binding protein (C/EBP), which then modulate APP gene expression. The transcriptional regulation of RBP4 by IL-6 is not fully understood. Therefore, this study aimed to elucidate the molecular mechanisms of PPARα and C/EBP isoforms in mediating IL-6 regulation of RBP4 gene expression. IL-6 was shown to reduce the transcriptional activity of RBP4, and functional dissection of the RBP4 promoter further identified the cis-acting regulatory elements that are responsible in mediating the inhibitory effect of IL-6. The binding sites for PPARα and C/EBP present in the RBP4 promoter were predicted at -1079 bp to -1057 bp and -1460 bp to -1439 bp, respectively. The binding of PPARα and C/EBPs to their respective cis-acting elements may lead to antagonistic interactions that modulate the IL-6 regulation of RBP4 promoter activity. Therefore, this study proposed a new mechanism of interaction involving PPARα and different C/EBP isoforms. This interaction is necessary for the regulation of RBP4 gene expression in response to external stimuli, particularly IL-6, during physiological changes.

Impaired Peroxisomal Fitness in Obese Mice, a Vicious Cycle Exacerbating Adipocyte Dysfunction via Oxidative Stress

Aims: Peroxisome is a critical organelle for fatty acid oxidation (FAO) and metabolism of reactive oxygen species (ROS). Increased oxidative stress in adipose tissue contributes to the development of insulin resistance and metabolic syndrome in obesity. This study aimed to investigate the role of peroxisomal fitness in maintaining adipocyte function, which has been under-rated in the obesity research area. Results: Reduced peroxisomal gene expressions in white adipose tissue (WAT) of obese mice suggested a close correlation between peroxisomes and obesity. Peroxisomal biogenesis factor 5 siRNA increased cellular ROS and inflammatory mediators in 3T3-L1 adipocytes. On the contrary, hydrogen peroxide or tumor necrosis factor-α treatment significantly decreased biogenesis- and function-related peroxisomal proteins, suggesting a positive feedback loop of ROS/inflammation and peroxisomal dysfunction. Correspondingly, catalase (a major peroxisomal antioxidant)-knockout mice fed with high-fat diet (HFD) exhibited suppressed peroxisomal proteins along with increased oxidative stress and accelerated obesity. In response to fenofibrate (a peroxisomal proliferator) treatment, WAT of HFD-fed wild-type mice showed not only increases in peroxisomal biogenesis and FAO but also attenuated features of adipocyte dysfunction and obesity. However, these results were not observed in peroxisome proliferator-activated receptor-alpha null obese mice. Innovation: Impaired peroxisomal fitness enhanced oxidative stress and inflammation in adipocytes, which exacerbates obesity. Conclusion: Adipose tissue peroxisomal homeostasis plays an important role in attenuating the features of obesity, and it can be a potential therapeutic target of obesity.

Molecular Actions of PPARα in Lipid Metabolism and Inflammation

Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor of clinical interest as a drug target in various metabolic disorders. PPARα also exhibits marked anti-inflammatory capacities. The first-generation PPARα agonists, the fibrates, have however been hampered by drug-drug interaction issues, statin drop-in, and ill-designed cardiovascular intervention trials. Notwithstanding, understanding the molecular mechanisms by which PPARα works will enable control of its activities as a drug target for metabolic diseases with an underlying inflammatory component. Given its role in reshaping the immune system, the full potential of this nuclear receptor subtype as a versatile drug target with high plasticity becomes increasingly clear, and a novel generation of agonists may pave the way for novel fields of applications.

PPARα Agonist Fenofibrate Reduced the Secreting Load of β-Cells in Hypertriglyceridemia Patients with Normal Glucose Tolerance

Hypertriglyceridemia is an important risk factor associated with insulin resistance and β-cell dysfunction. This study investigated the effects of hypertriglyceridemia and fenofibrate treatment on insulin sensitivity and β-cell function in subjects with normal glucose tolerance. A total of 1974 subjects with normal glucose tolerance were divided into the normal TG group (NTG group, n = 1302) and hypertriglyceridemia group (HTG group, n = 672). Next, 92 patients selected randomly from 672 patients with hypertriglyceridemia were assigned to a 24-week fenofibrate treatment. The HTG group had increased waist circumference (WC), body mass index (BMI), homeostasis model assessment of insulin resistance (HOMA-IR), and homeostasis model assessment of β-cell function (HOMA-β) and decreased high-density lipoprotein cholesterol (HDL-C) compared with the NTG group (all P < 0.01). The 24-week fenofibrate treatment significantly decreased the WC, BMI, TG, HOMA-IR, and HOMA-β levels and increased the HDL-C levels in the patients with hypertriglyceridemia (WC, BMI, and HOMA-IR: P < 0.05; TG, HDL-C, and HOMA-β: P < 0.01). The fenofibrate treatment significantly alleviated insulin resistance and reduced the secreting load of β-cells in the hypertriglyceridemia patients with normal glucose tolerance.

Assessment of Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Retinol-Binding Protein 4 (RBP4) in Type 2 Diabetic Patients with Nephropathy

Diabetic nephropathy (DN) is one of the most serious microvascular complications of diabetes. The study aims to evaluate the diagnostic value of serum neutrophil gelatinase-associated lipocalin (NGAL) and retinol-binding protein 4 (RBP4) as biomarkers for early detection of nephropathy in type 2 diabetic patients. The current study was performed on 150 type 2 diabetic patients. These patients were classified into three equal groups according to their albumin/creatinine ratio (ACR), including patients with normoalbuminuria (ACR <30 mg/g creatinine), patients with microalbuminuria (ACR = 30-300 mg/g creatinine), and patients with macroalbuminuria (ACR >300 mg/g creatinine). Fifty apparently healthy subjects matching the same age and socioeconomic status with diabetic subjects were selected as a control group. The plasma glucose, insulin, glycosylated hemoglobin (HbA1c), homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile, urea, creatinine, cystatin C, glomerular filtration rate (GFR), NGAL, and RBP4 were measured in the studied groups. Significantly elevated NGAL and RBP4 levels were observed in micro- and macroalbuminuric diabetic groups when compared to the control and normoalbuminuric diabetic groups. NGAL and RBP4 were found to correlate positively with duration of diabetes, systolic and diastolic blood pressure, glucose, HbA1c, HOMA-IR, triacylglycerol, and ACR, but correlate inversely with GFR in DN groups. Receiver operating characteristic curves revealed that for early detection of DN, the best cutoff values to discriminate DN and diabetic without nephropathy groups were 91.5 ng/mL for NGAL with 87% sensitivity, 74% specificity, and area under the curve (AUC) = 0.881; 24.5 ng/mL for RBP4 with 84% sensitivity, 90% specificity, and AUC = 0.912; and 37.5 mg/g creatinine for ACR with 89% sensitivity, 72% specificity, and AUC = 0.819. RBP4 is more specific (90% specificity) than NGAL (74% specificity) and ACR (72% specificity). Therefore, RBP4 marker may serve as a tool to follow-up clinical monitoring of the development and progression of DN.

Vitamins and their derivatives in the prevention and treatment of metabolic syndrome diseases (diabetes),

A cluster of inter-related conditions such as central obesity, dyslipidemia, impaired glucose metabolism, and hypertension is referred to as Metabolic Syndrome, which is a risk factor for the development of type-2 diabetes. The micro- and macro-vascular complications of diabetes contribute to its morbidity and mortality. In addition to its calcitropic effect, vitamin D is a regulator of gene expression as well as cell proliferation and differentiation. Various cross-sectional and longitudinal cohort studies have indicated a beneficial effect from vitamin D supplementation on the development of type-2 diabetes. Binding of retinol-bound retinol-binding protein to a membrane-binding protein suppresses insulin signaling. All-trans retinoic acid, a derivative of vitamin A, reverses these effects, resulting in increased insulin sensitivity, suppression of the phosphoenolpyruvate carboxy kinase (PEPCK) gene, and the induction of the glucokinase gene. Glucokinase and PEPCK are also regulated in opposite directions by the vitamin biotin, acting at the transcriptional level. Biotin also regulates the synthesis of insulin by the islet of Langerhans cells of the pancreas. The increase in advanced glycation end products (AGEs) is implicated in the initiation and progression of diabetes-associated microvascular diseases. Benfotiamine, a derivative of thiamine, and pyridoxamine, a vitamer of vitamin B6, both have anti-AGE properties, making them valuable therapeutic adjuvants in the treatment of diabetic complications. Thus, various vitamins and their derivatives have profound therapeutic potential in the prevention and treatment of type-2 diabetes.

Fenofibrate increases serum vaspin by upregulating its expression in adipose tissue

Fenofibrate is a peroxisome proliferator-activated receptor-α that has been clinically used to treat dyslipidemia and insulin resistance. To better understand the molecular mechanisms underlying fenofibrate action, we investigated whether fenofibrate affects serum levels of vaspin, an adipocytokine that has recently been shown to link obesity and insulin resistance. Fenofibrate treatment significantly increased serum vaspin levels of dyslipidemic patients, which correlated with reduced body weight and increased insulin sensitivity. To elucidate the biochemical mechanisms of fenofibrate action, we investigated the effect of fenofibrate on vaspin mRNA and protein expressions in obese rats. Fenofibrate greatly increased vaspin mRNA and protein levels in visceral adipose tissue consisting of retroperitoneal, mesenteric, and periepididymal adipose tissue but not in the subcutaneous adipose tissue, which correlated with increased serum vaspin levels and increased insulin sensitivity in obese rats. Consistent with a direct effect on vaspin expression, fenofibrate treatment significantly increased the mRNA and protein expression levels of vaspin in 3T3-L1 adipocytes. Together, our results demonstrate for the first time that fenofibrate upregulates vaspin expression in dyslipidemic human subjects and suggest that upregulation of vaspin expression in adipocytes may provide a mechanism by which fenofibrate improves insulin sensitivity in dyslipidemic patients.

The complex P2X7 receptor/inflammasome in perivascular fat tissue of heavy smokers

OBJECTIVE

Smoking is a recognized cardiovascular risk factor. Perivascular visceral adipose tissue (PVAT) is a source of inflammatory molecules, thus contributing to atherosclerosis progression. The P2X7 receptor (P2X7 R)-inflammasome complex, crucial in determining IL-1β and IL-18 release, participates in this scenario. We evaluated whether smoking might affect the PVAT inflammatory phenotype and explored the putative role of the axis P2X7 R-inflammasome in this picture.

SUBJECTS AND METHODS

TNFα, IL-6, RBP4, MCP-1, as well as P2X7 R and inflammasome components NLRP3, ASC, caspase-1 and IL-1β and IL-18 expression was determined in adipocytes isolated by PVAT of healthy smokers (Smok) and nonsmokers (No-Smok) subjects. Plasma and culture medium levels of these cytokines were also determined.

RESULTS

Perivascular adipose tissue of Smok had a higher expression of P2X7 R and inflammasome components; via P2X7 R activation, it released more IL-1β and IL-18, whose serum levels were also higher in Smok than in No-Smok. Linear correlations of NLRP3 with P2X7 R and IL-18 expression and release emerged. Smok also had a higher PVAT expression of the chemotactic factor MCP-1. However, no difference was observed in the PVAT expression of genes more strictly related to insulin resistance, like TNFα, RBP4, IL-6; this was coupled with similar plasma levels of TNFα and RBP4 in the two groups.

CONCLUSION

Smoking contributes to the pro-inflammatory status of the PVAT by enhancing expression and activity of the P2X7 R-inflammasome complex; the effect on adipocytokines more related to insulin resistance and metabolic abnormalities appears trivial.

Higher serum retinol binding protein 4 may be a predictor of weak metabolic control in chinese patients with type 2 diabetes mellitus

OBJECTIVE

To investigate relationships between serum levels of retinol binding protein 4 (RBP4) and clinical and metabolic variables in Chinese patients with type 2 diabetes mellitus.

METHODS

A total of 513 patients (286 males/227 females) provided clinical and lifestyle data and blood and urine samples for analysis. Patients were stratified into four quartile groups according to serum RBP4 concentrations.

RESULTS

RBP4 concentration was independently associated with gender, systolic blood pressure, serum triglyceride and creatinine levels, and estimated glomerular filtration rate (eGFR). Hypertension, dyslipidaemia, micro albuminuria and impaired eGFR (<60 ml/min per 1.73 m2) were significantly more prevalent in patients with the highest RBP4 levels than in those with the lowest levels. Increased serum RBP4 was associated with increased risk of hypertension, dyslipidaemia, micro albuminuria and impaired eGFR after adjusting for gender, age, body mass index and duration of diabetes.

CONCLUSION

Serum RBP4 may be a useful marker of overall metabolic control in Chinese patients with type 2 diabetes mellitus.

Long-term fenofibrate therapy increases fibroblast growth factor 21 and retinol-binding protein 4 in subjects with type 2 diabetes

CONTEXT

Fenofibrate is a peroxisome proliferator-activated receptor (PPAR)-α agonist that showed beneficial effects on total cardiovascular risk in patients with type 2 diabetes in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study.

OBJECTIVE

This study aimed to investigate the long-term effect of fenofibrate therapy on three novel biomarkers of cardiovascular risk, namely adipocyte-fatty acid-binding protein (A-FABP), fibroblast growth factor 21 (FGF21), and retinol-binding protein 4 (RBP4), which are all downstream targets of PPAR-α or PPAR-γ, in patients with type 2 diabetes.

DESIGN, SETTING, AND PATIENTS

A total of 216 patients (108 in the fenofibrate group and 108 in the placebo group) were randomly selected from the FIELD study cohort. A-FABP, FGF21, and RBP4 levels were measured in serum samples at both baseline and the fifth year of the study.

RESULTS

Relative to the placebo group, the changes of serum FGF21 and RBP4 levels were 85% (P < 0.001) and 10% (P = 0.032) higher in the fenofibrate group, respectively, over 5 yr. Fenofibrate treatment had no detectable effect on serum A-FABP level (P > 0.05). The effect of fenofibrate treatment on serum FGF21, but not RBP4, remained significant after adjusting for fenofibrate-induced changes in glycosylated hemoglobin, total cholesterol, triglycerides, apolipoprotein A-II, fibrinogen, plasma creatinine, and homocysteine (P = 0.002).

CONCLUSIONS

Long-term fenofibrate treatment could increase serum FGF21 levels over 5 yr in patients with type 2 diabetes. Additional studies are needed to investigate the potential role of FGF21 in the fenofibrate-mediated reduction of cardiovascular risk.

Peroxisome proliferator-activated receptors-α and -γ, and cAMP-mediated pathways, control retinol-binding protein-4 gene expression in brown adipose tissue

Retinol binding protein-4 (RBP4) is a serum protein involved in the transport of vitamin A. It is known to be produced by the liver and white adipose tissue. RBP4 release by white fat has been proposed to induce insulin resistance. We analyzed the regulation and production of RBP4 in brown adipose tissue. RBP4 gene expression is induced in brown fat from mice exposed to cold or treated with peroxisome proliferator-activated receptor (PPAR) agonists. In brown adipocytes in culture, norepinephrine, cAMP, and activators of PPARγ and PPARα induced RBP4 gene expression and RBP4 protein release. The induction of RBP4 gene expression by norepinephrine required intact PPAR-dependent pathways, as evidenced by impaired response of the RBP4 gene expression to norepinephrine in PPARα-null brown adipocytes or in the presence of inhibitors of PPARγ and PPARα. PPARγ and norepinephrine can also induce the RBP4 gene in white adipocytes, and overexpression of PPARα confers regulation by this PPAR subtype to white adipocytes. The RBP4 gene promoter transcription is activated by cAMP, PPARα, and PPARγ. This is mediated by a PPAR-responsive element capable of binding PPARα and PPARγ and required also for activation by cAMP. The induction of the RBP4 gene expression by norepinephrine in brown adipocytes is protein synthesis dependent and requires PPARγ-coactivator-1-α, which acts as a norepinephine-induced coactivator of PPAR on the RBP4 gene. We conclude that PPARγ- and PPARα-mediated signaling controls RBP4 gene expression and releases in brown adipose tissue, and thermogenic activation induces RBP4 gene expression in brown fat through mechanisms involving PPARγ-coactivator-1-α coactivation of PPAR signaling.

The changes in plasma retinol-binding protein 4 levels are associated with those of the apolipoprotein B-containing lipoproteins during dietary and drug treatment

We investigated the association between retinol-binding protein 4 (RBP(4)) and apolipoprotein B (ApoB)-containing lipoproteins. Obese or overweight, hypertriglyceridemic patients underwent the following interventions for 3 months: (1) Diet (n = 20), (2) Diet + fenofibrate (n = 18), (3) Diet + rimonabant (n = 8). Circulating RBP4 decreased during dietary treatment. The percentage change in RBP(4) was positively correlated with the percentage changes in very-low density lipoprotein cholesterol (r = .570, P = .02), low-density lipoprotein cholesterol ([LDL-C]; r = .605, P = .01), ApoB (r = .705, P = .007), and small dense LDL-C ([sdLDL-C]; r = .872, P < .001). The percentage change in RBP4 was the best predictor of the percentage changes in sdLDL-C and ApoB. Rimonabant treatment reduced RBP4, whereas fenofibrate increased RBP4 during the first month of therapy followed by a subsequent decrease. In conclusion, RBP4 may significantly influence the metabolic pathways responsible for changes in ApoB lipoprotein subspecies, thus RBP4 may be associated with cardiovascular disease risk.

Retinol-binding protein 4 and peroxisome proliferator-activated receptor-γ in steatotic liver transplantation

Numerous steatotic livers are discarded for transplantation because of their poor tolerance of ischemia-reperfusion (I/R). The injurious effects of retinol-binding protein 4 (RBP4) in various pathologies are well documented. RBP4 levels are reduced by peroxisome proliferator-activated receptor-γ (PPARγ) agonists. Strategies aimed at increasing PPARγ protect steatotic livers under warm ischemia. Ischemic preconditioning (PC) based on brief periods of I/R protects steatotic liver grafts against I/R injury, but the responsible mechanism is poorly understood. We examined the roles of RBP4 and PPARγ in I/R injury associated with steatotic liver transplantation and the benefits of PC in such situations. We report that RBP4 and PPARγ expression levels in nonsteatotic livers were similar to those found in the sham group. However, reduced RBP4 and increased PPARγ levels were observed in steatotic livers. Treatment with either RBP4 or a PPARγ antagonist was effective only in steatotic livers. PC, which increased RBP4 levels, and RBP4 treatment both reduced PPARγ levels and hepatic injury in steatotic livers. When PPARγ was activated, neither RBP4 treatment nor PC (despite RBP4 induction) protected steatotic livers. In conclusion, steatotic liver grafts are more predisposed to down-regulate RBP4 and overexpress PPARγ. RBP4 treatment and PC, through RBP4 induction, reduced PPARγ levels in steatotic liver grafts, thus protecting them from the PPARγ detrimental effects.

Pharmacological and non-pharmacological interventions to influence adipose tissue function

Obesity is associated with metabolic derangements such as insulin resistance, inflammation and hypercoagulobility which can all be understood as consequences of adipose tissue dysfunction. The potential role for adipose tissue derived cytokines and adipokines in the development of vascular disease and diabetes may produce a clinical need to influence adipose tissue function. Various pharmacological and non-pharmacological interventions affect plasma cytokine and adipokine levels. The effects of these interventions depend on weight loss per se, changes in fat distribution without weight loss and/or direct effects on adipose tissue inflammation.

Weight loss, as a result of diet, pharmacology and surgery, positively influences plasma adipokines and systemic inflammation. Several classes of drugs influence systemic inflammation directly through their anti-inflammatory actions. PPAR-γ agonism positively influences adipose tissue inflammation in several classes of intervention such as the thiazolidinediones and perhaps salicylates, CB1-antagonists and angiotensin II receptor blockers. Furthermore, within drug classes there are differential effects of individual pharmacologic agents on adipose tissue function.

It can be concluded that several commonly used pharmacological and non-pharmacological interventions have unintended influences on adipose tissue function. Improving adipose tissue function may contribute to reducing the risk of vascular diseases and the development of type 2 diabetes.

Regression to normoglycaemia by fenofibrate in pre-diabetic subjects complicated with hypertriglyceridaemia: a prospective randomized controlled trial

AIMS

Lipotoxicity has recently been shown to be an important risk factor underlying the pathogenesis of pre-diabetes. However, clinical evidence supporting the treatment of pre-diabetes by improving lipotoxicity is lacking. Here, we conducted an open-label, randomized, controlled trial to investigate whether fenofibrate, the widely used hypolipidaemic agent, might benefit pre-diabetes, with metformin and diet control, the recommended intervention methods, as positive controls.

METHODS

Newly diagnosed pre-diabetes patients (n = 120) with hypertriglyceridaemia (plasma triglyceride levels between 1.8 and 4.5 mmol/l) were randomly assigned by computer-generated randomization sequence to either control group (no intervention), fenofibrate group (200 mg once a day), metformin group (500 mg three times a day) or diet-controlled group (diet recommendation). Plasma biochemistry examination was performed every 2 months. The primary endpoint was the outcome of the natural course of pre-diabetes, evaluated by oral glucose tolerance test after 6-month follow-up.

RESULTS

Twenty subjects in the fenofibrate group, 24 subjects in the metformin group and 25 subjects in both the diet-controlled group and the control group finished the trial. Fenofibrate, metformin and diet control had protective effects on hypertriglyceridaemic pre-diabetes, evidenced by 53.3, 70 and 30% participants regressed to normoglycaemia, respectively. The effects of fenofibrate and metformin were comparable (P > 0.05), while diet control was less effective (P < 0.05). Liver damage occurred in six subjects in the fenofibrate group and gastrointestinal symptoms occurred in four subjects in the metformin group. No serious adverse events occurred.

CONCLUSION

Controlling lipotoxicity by fenofibrate could effectively ameliorate the natural course of hypertriglyceridaemic pre-diabetes.

Pharmacological effects of lipid-lowering drugs on circulating adipokines

The cardioprotective effects of lipid-lowering drugs have been primarily attributed to their effects on blood lipid metabolism. However, emerging evidence indicates that lipid-lowering drugs also modulate the synthesis and secretion of adipose tissue-secreted proteins referred to as adipokines. Adipokines influence energy homeostasis and metabolism and have also been shown to modulate the vascular inflammatory cascade. The purpose of this review will be to examine the reported effects of commonly used lipid-lowering drugs (statins, fibrates, niacin and omega-3-fatty acids) on the circulating concentrations of leptin, adiponectin, tumor necrosis-factor-α (TNF-α), Retinol binding protein 4 (RBP4) and resistin. Overall, the lipid-lowering drugs reviewed have minimal effects on leptin and resistin concentrations.Conversely, circulating adiponectin concentrations are consistently increased by each lipid-lowering drug reviewed with the greatest effects produced by niacin. Studies that have examined the effects of statins, niacin and omega-3-fatty acids on TNF-α demonstrate that these agents have little effect on circulating TNF-α concentrations. Niacin and fibrates appear to lower RBP4 but not resistin concentrations. The results of the available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and adiponectin that is not obvious for other adipokines reviewed.

Transcriptional targets in adipocyte biology

The global burden of metabolic disease demands that we develop new therapeutic strategies. Many of these approaches may center on manipulating the behavior of adipocytes, which contribute directly and indirectly to a host of disease processes including obesity and type 2 diabetes. One way to achieve this goal will be to alter key transcriptional pathways in fat cells, such as those regulating glucose uptake, lipid handling, or adipokine secretion. In this review, we look at what is known about how adipocytes govern their physiology at the gene expression level, and discuss novel ways that we can accelerate our understanding of this area.