Early macrophage response to obesity encompasses Interferon Regulatory Factor 5 regulated mitochondrial architecture remodelling

Adipose tissue macrophages (ATM) adapt to changes in their energetic microenvironment. Caloric excess, in a range from transient to diet-induced obesity, could result in the transition of ATMs from highly oxidative and protective to highly inflammatory and metabolically deleterious. Here, we demonstrate that Interferon Regulatory Factor 5 (IRF5) is a key regulator of macrophage oxidative capacity in response to caloric excess. ATMs from mice with genetic-deficiency of Irf5 are characterised by increased oxidative respiration and mitochondrial membrane potential. Transient inhibition of IRF5 activity leads to a similar respiratory phenotype as genomic deletion, and is reversible by reconstitution of IRF5 expression. We find that the highly oxidative nature of Irf5-deficient macrophages results from transcriptional de-repression of the mitochondrial matrix component Growth Hormone Inducible Transmembrane Protein (GHITM) gene. The Irf5-deficiency-associated high oxygen consumption could be alleviated by experimental suppression of Ghitm expression. ATMs and monocytes from patients with obesity or with type-2 diabetes retain the reciprocal regulatory relationship between Irf5 and Ghitm. Thus, our study provides insights into the mechanism of how the inflammatory transcription factor IRF5 controls physiological adaptation to diet-induced obesity via regulating mitochondrial architecture in macrophages.

Interferon Regulatory Factor 5 levels have been shown to increase in adipose tissue macrophages in diet-induced obesity. Here authors show that IRF5 transcriptionally represses the Growth Hormone Inducible Transmembrane Protein gene encoding a mitochondrial protein important for oxidative respiration in macrophages, thus driving the detrimental metabolic changes observed in obesity.

Waveguide-based absorption measurement system for visible wavelength applications

We present a miniaturized waveguide-based absorption measurement system operating at a wavelength of 635 nm, based on a silicon nitride integrated photonic platform, suitable for lab-on-chip applications. We experimentally demonstrate a high correlation between the bulk dye concentration and the measured absorption loss levels in the waveguides. We explain a photonic design process for choosing the ideal waveguide to minimize the coefficient of variation on the analyte concentration. The approach is designed for camera readout, allowing multiple readouts and easy integration for lab-on chip cartridge approach.

[Renal aspects of sodium glucose cotransporter 2 inhibitors]

It has been known for centuries that the kidneys play a role in glucose homeostasis, yet the underlying tubular mechanisms have only been recently identified by studying patients with familial glucosuria. These insights have lead to the commercialization of a novel class of oral antidiabetic agents named gliflozines. Gliflozines induce renal glucosuria by blocking the Na-glucose cotransporter SGLT2, localized in the proximal tubule, and allow a reduction of 0.5 to 1% of glycated hemoglobin. They also diminish proximal sodium reabsorption, and reduce the glomerular hyperfiltration that is often seen in the early stages of diabetes. Preliminary data suggest that they may decrease blood pressure and have renoprotective effects. This article provides an overview of the role of kidneys in glucose homeostasis and the renal effects of SGLT2-inhibitors.

[Contrast-induced nephropathy]

Iodine and gadolinium-based contrast induced nephropathy is the third leading cause of hospital-acquired acute kidney injury. It is essentially observed in patients with defined risk factors and is associated with increased morbidity and mortality. The prevention of contrast induced nephropathy consists in volume expansion through intravenous sodium chloride 0.9% or sodium bicarbonate 1.4%. Comparative randomized controlled trials appear to show a benefit in favor of sodium bicarbonate over saline fluids. According to last evidence, N-acetylcysteine does not provide additional benefit over intravenous fluids.

[Myoclonia in an oldest old woman: a frequent and reversible etiology]

A 98-year-old woman was referred to our hospital because of myoclonia. The concentration of calcium and vitamin D in the serum was low. In this context, we concluded of neuromuscular irritability secondary to hypocalcaemia. The symptoms disappeared after a treatment of intravenous calcium. This case shows how important it is to investigate electrolytes in case of neuromuscular irritability symptoms in elderly people.

Comparison of sludge and clinical isolates of Listeria monocytogenes

AIMS

Listeria monocytogenes strains isolated in the same geographical area from sewage sludge and from patients presenting with listeriosis were compared.

METHODS AND RESULTS

All isolates were typed by serotyping, phage typing and SmaI/ApaI pulsed-field gel electrophoresis (PFGE). Among the sludge isolates (n=32), 22 subtypes could be distinguished by the combination of all typing methods. The human isolates (n=11) were distributed into 10 subtypes which clearly differed from those observed among sludge isolates, except for one cluster formed by two related human isolates which showed high similarity in PFGE patterns (SmaI: 92%; ApaI: 89.5%) with one sludge isolate.

CONCLUSION

These results suggest the existence of an epidemiological link between sludge and human isolates, but they may also be reflecting the distribution of L. monocytogenes types within the environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Sludge and human L. monocytogenes may be related but further epidemiological studies are necessary to elucidate this point.