DNA methylation is altered in B and NK lymphocytes in obese and type 2 diabetic human

Objective

Obesity is associated with low-grade inflammation and the infiltration of immune cells in insulin-sensitive tissues, leading to metabolic impairment. Epigenetic mechanisms control immune cell lineage determination, function and migration and are implicated in obesity and type 2 diabetes (T2D). The aim of this study was to determine the global DNA methylation profile of immune cells in obese and T2D individuals in a cell type-specific manner.

Material and methods

Fourteen obese subjects and 11 age-matched lean subjects, as well as 12 T2D obese subjects and 7 age-matched lean subjects were recruited. Global DNA methylation levels were measured in a cell type-specific manner by flow cytometry. We validated the assay against mass spectrometry measures of the total 5-methylcytosine content in cultured cells treated with the hypomethylation agent decitabine (r = 0.97, p < 0.001).

Results

Global DNA methylation in peripheral blood mononuclear cells, monocytes, lymphocytes or T cells was not altered in obese or T2D subjects. However, analysis of blood fractions from lean, obese, and T2D subjects showed increased methylation levels in B cells from obese and T2D subjects and in natural killer cells from T2D patients. In these cell types, DNA methylation levels were positively correlated with insulin resistance, suggesting an association between DNA methylation changes, immune function and metabolic dysfunction.

Conclusions

Both obesity and T2D are associated with an altered epigenetic signature of the immune system in a cell type-specific manner. These changes could contribute to the altered immune functions associated with obesity and insulin resistance.     

Soft robotic in the construction of prosthetic heart valve: a novel approach

Abstract

In this study, we describe the design, fabrication and computational testing of a new prosthetic device for aortic valve replacement. The device is an active stent composed of a silicone rubber during initial prototyping, with adaptation towards a hydrogel, poly-vinyl alcohol reinforced with bacterial cellulose nanofibres underway. The nature of the stent is soft robotic (SR), where an increase in internal pressure of the pneumatic network causes an increase in the internal diameter of the device. When working in tandem with the SR heart valve, described briefly, pulsations of the blood and the energy gained from ventricular pressure actuates the valve-and-stent combination. This increases the effective orifice area of the entire device and addresses an issue with small sized heart valves facing prosthesis–patient mismatch.     

How do I manage an acute injury to the facial nerve?

Paralysis of the facial nerve is a cause of considerable functional and aesthetic disfigurement. Damage to the upper trunk can result in eye complications with the risk of exposure keratitis. Numerous factors influence the therapeutic strategy: the cause of the injury, the time elapsed since injury, functional impairment, and the likelihood of recovery. We discuss the management of an acute injury to the facial nerve and focus on the surgical options.