Common promoter polymorphism in monocyte differentiation antigen CD14 is associated with serum triglyceride levels and body mass index in non-diabetic individuals

Innate-Immunity Genes in Obesity

The main functions of adipose tissue are thought to be storage and mobilization of the body’s energy reserves, active and passive thermoregulation, participation in the spatial organization of internal organs, protection of the body from lipotoxicity, and ectopic lipid deposition. After the discovery of adipokines, the endocrine function was added to the above list, and after the identification of crosstalk between adipocytes and immune cells, an immune function was suggested. Nonetheless, it turned out that the mechanisms underlying mutual regulatory relations of adipocytes, preadipocytes, immune cells, and their microenvironment are complex and redundant at many levels. One possible way to elucidate the picture of adipose-tissue regulation is to determine genetic variants correlating with obesity. In this review, we examine various aspects of adipose-tissue involvement in innate immune responses as well as variants of immune-response genes associated with obesity.

Biomarkers of microbial translocation and macrophage activation: association with progression of subclinical atherosclerosis in HIV-1 infection

BACKGROUND

The relationships between soluble CD14 (sCD14), endotoxin (lipopolysaccharide [LPS]), and progression of atherosclerosis have not been defined in human immunodeficiency virus (HIV) infection.

METHODS

We retrospectively assessed serum sCD14 and LPS levels of 91 subjects in a prospective 3-year study of carotid artery intima-media thickness (CIMT) (AIDS Clinical Trials Group [ACTG] 5078), where subjects were enrolled as risk factor-controlled triads of HIV-uninfected (n = 36) and HIV-infected individuals with (n = 29) or without (n = 26) protease inhibitor (PI)-based therapy for ≥2 years. The primary end point was the yearly rate of change of CIMT (ΔCIMT).

RESULTS

In multivariate analysis of the HIV-infected subjects, each 1 µg/mL above the mean of baseline serum sCD14 corresponded to an additional 1.52 µm/y (95% confidence interval, .07-2.98; P = .04) in the ΔCIMT. Every 100 pg/mL above the mean of baseline serum LPS corresponded to an additional 0.49 µm/y (95% confidence interval, .18-.81; P = .003) in the ΔCIMT. However, in univariate analysis in the HIV-uninfected group sCD14 (P = .33) and LPS (P = .27) levels were not associated with higher ΔCIMT. HIV infection and PI therapy were not associated with baseline serum LPS and sCD14 levels (P > .1).

CONCLUSIONS

Our data are among the first to suggest that serum biomarkers of microbial translocation (LPS) and macrophage activation (sCD14) predict subclinical atherosclerosis progression in HIV-infected persons.

The search for genetic risk factors of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is caused by complex interplay between multiple genetic and environmental factors. The three major approaches used to identify the genetic susceptibility include candidate gene approach, familial linkage analysis and genome- wide association analysis. Recent advance in genome-wide association studies have greatly improved our understanding of the pathophysiology of T2DM. As of the end of 2010, there are more than 40 confirmed T2DM-associated genetic loci. Most of the T2DM susceptibility genes were implicated in decreased β-cell function. However, these genetic variations have a modest effect and their combination only explains less than 10% of the T2DM heritability. With the advent of the next-generation sequencing technology, we will soon identify rare variants of larger effect as well as causal variants. These advances in understanding the genetics of T2DM will lead to the development of new therapeutic and preventive strategies and individualized medicine.

Lack of effect of the CD14 promoter gene C-159T polymorphism on nutritional status parameters in hemodialysis patients

Background

CD14 is a membrane glycoprotein that acts as a co-receptor for the detection of bacterial lipopolysaccharide (LPS). Mutual interaction between CD14 and LPS plays an important role in the innate immune system. Increased serum soluble CD14 levels have been described in hemodialysis (HD) patients, and linked to increased mortality risk, inflammation and protein-energy wasting. The expression of CD14 may be influenced by CD14 promoter gene C-159T polymorphism.

This study aimed to clarify the possible association between CD14 promoter gene C-159T polymorphism and nutritional status in hemodialysis patients.

Material/Methods

The study population consisted of 185 (104 males; 81 females) long-term HD patients treated in 5 dialysis centers. The control group consisted of 112 apparently healthy volunteers (32 males and 80 females). Nutritional status was assessed using a modified SGA scale, and anthropometric methods (BMI, WHR, waist, hip and mid-arm circumferences, biceps, triceps, subocular and subscapular skinfolds). Biochemical parameters evaluated included: CRP, albumin, creatinine, urea, cholesterol, triglycerides and TIBC. CD14 promoter gene C-159T polymorphism was determined by restriction fragment length polymorphism, after digestion of the PCR product with Hae III restriction endonuclease.

Results

Genotype and allele frequencies were similar to controls and compliant with Hardy-Weinberg equilibrium. No between-group differences were detected in measured variables with the exception of lower triglyceride levels in carriers of C allele in comparison to TT genotype.

Conclusions

CD14 promoter gene C-159T polymorphism does not seem to be associated with nutritional status parameters in HD patients. It does seem, however, to influence triglyceride blood levels.

Obesity, innate immunity and gut inflammation

PURPOSE OF REVIEW

The purpose of this review is to present recent data on how obesity-associated conditions may affect innate immunity and its role in the development of gut inflammation.

RECENT FINDINGS

Here we present studies that demonstrate the participation of adipose tissue components in the generation of inflammation. More specifically, we describe increases in the release of proinflammatory cytokines during obesity as well as the expression of receptors involved in innate immune responses by adipocytes. Furthermore, we present data on the involvement of adipose tissue-specific molecules (adipokines) in the generation of an environment that is favorable for diseases with an immune cause and in some cases (leptin) directly contribute to the development of inflammatory bowel disease. Finally, we present evidence supporting a putative association between obesity and gut inflammation through the link of inflammation with angiogenesis and neovascularization and the favorable conditions created for these responses in obesity.

SUMMARY

We believe that obesity-related systemic changes may create conditions that predispose to the development of gut inflammation or even worsen the progression of ongoing disease.

Inflammation in metabolic syndrome and type 2 diabetes: Impact of dietary glucose

Chronic overnutrition combined with a lack of exercise is the main cause for the rapidly increasing prevalence of overweight and obesity. It seems accepted that adipositis (macrophage infiltration and inflammation of adipose tissue in obesity) and systemic low grade inflammation affect the pathogenesis of the metabolic syndrome or type 2 diabetes mellitus (T2DM). Therefore, modern weight reduction programs additionally focus on strategies to attenuate the inflammation state. Exercise is one major factor, which contributes to the reduction of both the incidence of T2DM and inflammation, and the immunomodulatory effects of exercise are supported by similarly beneficial effects of dietary changes. In this context, glucose is the most extensively studied nutrient and current investigations focus on postprandial glucose-induced inflammation, one possible reason why hyperglycemia is detrimental. Indeed, glucose may modulate the mRNA expression and serum concentrations of immune parameters but these alterations rapidly normalize in normoglycemic subjects. In case of an impaired metabolic state, however, postprandial hyperglycemia increases magnitude and duration of systemic inflammatory responses, which probably promotes the development of T2DM and of cardiovascular disease.