Renal insulin resistance in type 2 diabetes mellitus and progression of chronic kidney disease: potential pathogenic mechanisms

INTRODUCTION

A bidirectional association exists between insulin resistance (IR) and chronic kidney disease (CKD) in Type 2 Diabetes Mellitus (T2DM). Baseline measures of IR are predictive of CKD progression, and uremia in progressive CKD is itself, in turn, associated with a worsening of IR. Pre-clinical research reveals that intrinsic IR in glomerular podocytes and the renal tubule may serve as a pathogenic driver of CKD in T2DM.

AREAS COVERED

The present manuscript takes as its point of departure, the recently identified prognostic utility of severe insulin resistance as a predictor of CKD in T2DM. Findings from a series of studies describing the association of IR with pathological alterations in both established, and less commonly assessed dynamic measures of renal impairment are discussed. Drawing upon the pre-clinical mechanistic evidence base, the cellular and molecular basis of intrinsic renal IR as a promoter of CKD is considered.

EXPERT OPINION

Measurement of insulin sensitivity may add value to profiling of renal risk in T2DM. Rational selection of therapeutic strategies targeting the enhancement of insulin sensitivity merits special attention regarding the personalized management of CKD in insulin resistance predominant T2DM.

The Molecular Effects of a High Fat Diet on Endometrial Tumour Biology

We sought to validate the BDII/Han rat model as a model for diet-induced obesity in endometrial cancer (EC) and determine if transcriptomic changes induced by a high fat diet (HFD) in an EC rat model can be used to identify novel biomarkers in human EC. Nineteen BDII/Han rats were included. Group A (n = 7) were given ad lib access to a normal calorie, normal chow diet (NCD) while Group B (n = 12) were given ad lib access to a calorie rich HFD for 15 months. RNAseq was performed on endometrial tumours from both groups. The top-ranking differentially expressed genes (DEGs) were examined in the human EC using The Cancer Genome Atlas (TCGA) to assess if the BDII/Han rat model is an appropriate model for human obesity-induced carcinogenesis. Weight gain in HFD rats was double the weight gain of NCD rats (50 g vs. 25 g). The incidence of cancer was similar in both groups (4/7-57% vs. 4/12-33%; p = 0.37). All tumours were equivalent to a Stage 1A, Grade 2 human endometrioid carcinoma. A total of 368 DEGs were identified between the tumours in the HFD group compared to the NCD group. We identified two upstream regulators of the DEGs, mir-33 and Brd4, and a pathway analysis identified downstream enrichment of the colorectal cancer metastasis and ovarian cancer metastasis pathways. Top-ranking DEGs included Tex14, A2M, Hmgcs2, Adamts5, Pdk4, Crabp2, Capn12, Npw, Idi1 and Gpt. A2M expression was decreased in HFD tumours. Consistent with these findings, we found a significant negative correlation between A2M mRNA expression levels and BMI in the TCGA cohort (Spearman's Rho = -0.263, p < 0.001). A2M expression was associated with improved overall survival (HR = 0.45, 95% CI 0.23-0.9, p = 0.024). Crabp2 expression was increased in HFD tumours. In human EC, CRABP2 expression was associated with reduced overall survival (HR = 3.554, 95% CI 1.875-6.753, p < 0.001). Diet-induced obesity can alter EC transcriptomic profiles. The BDII/Han rat model is a suitable model of diet-induced obesity in endometrial cancer and can be used to identify clinically relevant biomarkers in human EC.

Activating transcription factor 3 promotes loss of the acinar cell phenotype in response to cerulein-induced pancreatitis in mice

Pancreatitis is a debilitating disease of the exocrine pancreas that, under chronic conditions, is a major susceptibility factor for pancreatic ductal adenocarcinoma (PDAC). Although down-regulation of genes that promote the mature acinar cell fate is required to reduce injury associated with pancreatitis, the factors that promote this repression are unknown. Activating transcription factor 3 (ATF3) is a key mediator of the unfolded protein response, a pathway rapidly activated during pancreatic insult. Using chromatin immunoprecipitation followed by next-generation sequencing, we show that ATF3 is bound to the transcriptional regulatory regions of >30% of differentially expressed genes during the initiation of pancreatitis. Of importance, ATF3-dependent regulation of these genes was observed only upon induction of pancreatitis, with pathways involved in inflammation, acinar cell differentiation, and cell junctions being specifically targeted. Characterizing expression of transcription factors that affect acinar cell differentiation suggested that acinar cells lacking ATF3 maintain a mature cell phenotype during pancreatitis, a finding supported by maintenance of junctional proteins and polarity markers. As a result, Atf3-/- pancreatic tissue displayed increased tissue damage and inflammatory cell infiltration at early time points during injury but, at later time points, showed reduced acinar-to-duct cell metaplasia. Thus our results reveal a critical role for ATF3 as a key regulator of the acinar cell transcriptional response during injury and may provide a link between chronic pancreatitis and PDAC.

Hair MDMA samples are consistent with reported ecstasy use: findings from a study investigating effects of ecstasy on mood and memory

AIMS

Our group has conducted several Internet investigations into the biobehavioural effects of self-reported recreational use of MDMA (3,4-methylenedioxymethamphetamine or Ecstasy) and other psychosocial drugs. Here we report a new study examining the relationship between self-reported Ecstasy use and traces of MDMA found in hair samples.

METHODS

In a laboratory setting, 49 undergraduate volunteers performed an Internet-based assessment which included mood scales and the University of East London Drug Use Questionnaire, which asks for history and current drug use. They also provided a hair sample for determination of exposure to MDMA over the previous month.

RESULTS

Self-report of Ecstasy use and presence in hair samples were consistent (p < 0.00001). Both subjective and objective measures predicted lower self-reported ratings of happiness and higher self-reported stress. Self-reported Ecstasy use, but not presence in hair, was also associated with decreased tension.

CONCLUSION

Different psychoactive drugs can influence long-term mood and cognition in complex and dynamically interactive ways. Here we have shown a good correspondence between self-report and objective assessment of exposure to MDMA. These data suggest that the Internet has potentially high utility as a useful medium to complement traditional laboratory studies into the sequelae of recreational drug use.

Renal expression of interleukin-2 receptor mRNA in patients with crescentic glomerulonephritis

We studied paraffin sections of renal biopsies from 7 patients with crescentic glomerulonephritis (CGN) by in situ hybridisation, to detect sites of interleukin-2 receptor (IL-2R) mRNA expression. Frozen sections from a further patient with CGN were studied by immunohistochemistry with a monoclonal antibody to CD25, to detect IL-2R protein. Positive control sections were taken from biopsies of acute cellular renal transplant rejection and negative controls from biopsies of membranous glomerulonephritis. No autoradiographic signal was detected in negative controls. IL-2R mRNA expression was seen in rejected transplants and in sections from 4 to 7 patients with CGN. Expression was seen in cortical interstitial cells, renal tubular epithelial cells, cells within glomerular crescents and in one glomerulus at the margin of Bowman's capsule. Tubular cell expression of IL-2R protein was confirmed by immunohistochemistry. We have confirmed that IL-2R mRNA expression occurs locally within the kidneys in CGN and have identified expression in tubular epithelial cells. The results suggest that local activation of immunocompetent cells occurs in the kidney and may be of significance in the pathogenesis of CGN.

Gastric emptying in achalasia

Some investigators have postulated that patients with primary achalasia have a generalized upper gastrointestinal motility disorder. To evaluate gastric emptying in patients with primary achalasia, four patients were studied prospectively after successful brusque dilation. Gastric emptying of liquids and solids was normal in all patients. There is no defect in gastric emptying in patients with primary achalasia.

Isolated intrapulmonary haemorrhage. An unusual complication of internal jugular vein cannulation

A case of intrapulmonary haemorrhage following internal jugular vein cannulation is described and the subsequent treatment outlined. A cautionary note is expressed, especially when the procedure is performed in obese, thick-set individuals with chronic lung disease.

Interactions between Neutron and Proton

An attempt has been made to find an interaction between neutron and proton which will account for not only the binding energy and quadripole moment of the deuteron and the low energy scattering data, but also the results of the experiments on the scattering of 90 MeV. neutrons by protons. Three types of modification of the triplet neutron-proton interaction have been used which embody the following features : (1) A non-central potential of spherical well form, whose radius of interaction is varied. (2) A non-central potential whose form is closer to that of the pseudo-scalar meson potential than the usual Rarita-Schwinger form, but which does not possess the objectionable singularities of the former. (3) The inclusion of a large short-range repulsion. In each case exchange forces of the usual types have been used. The results obtained, like those of other workers in this field using different forms of interaction, fail to agree with the high energy data.