Deletion of p47phox attenuates the progression of diabetic nephropathy and reduces the severity of diabetes in the Akita mouse

AIMS/HYPOTHESIS

Reactive oxygen species (ROS) contribute to diabetes-induced glomerular injury and endoplasmic reticulum (ER) stress-induced beta cell dysfunction, but the source of ROS has not been fully elucidated. Our aim was to determine whether p47(phox)-dependent activation of NADPH oxidase is responsible for hyperglycaemia-induced glomerular injury in the Akita mouse, a model of type 1 diabetes mellitus resulting from ER stress-induced beta cell dysfunction.

METHODS

We examined the effect of deleting p47 (phox) (also known as Ncf1), the gene for the NADPH oxidase subunit, on diabetic nephropathy in the Akita mouse (Ins2 (WT/C96Y)) by studying four groups of mice: (1) non-diabetic mice (Ins2 (WT/WT)/p47 (phox+/+)); (2) non-diabetic p47 (phox)-null mice (Ins2 (WT/WT)/p47 (phox-/-)); (3) diabetic mice: (Ins2 (WT/C96Y)/p47 (phox+/+)); and (4) diabetic p47 (phox)-null mice (Ins2 (WT/C96Y)/p47 (phox-/-)). We measured the urinary albumin excretion rate, oxidative stress, mesangial matrix expansion, and plasma and pancreatic insulin concentrations in 16-week-old mice; we also measured glucose tolerance and insulin sensitivity, islet and glomerular NADPH oxidase activity and subunit expression, and pro-fibrotic gene expression in 8-week-old mice. In addition, we measured NADPH oxidase activity, subunit expression and pro-fibrotic gene expression in high glucose-treated murine mesangial cells.

RESULTS

Deletion of p47 (phox) reduced kidney hypertrophy, oxidative stress and mesangial matrix expansion, and also reduced hyperglycaemia by increasing pancreatic and circulating insulin concentrations. p47 (phox-/-) mice exhibited improved glucose tolerance, but modestly decreased insulin sensitivity. Deletion of p47 (phox) attenuated high glucose-induced activation of NADPH oxidase and pro-fibrotic gene expression in glomeruli and mesangial cells.

CONCLUSIONS/INTERPRETATION

Deletion of p47 (phox) attenuates diabetes-induced glomerular injury and beta cell dysfunction in the Akita mouse.

Development and validation of a prediction index for hand-foot skin reaction in cancer patients receiving sorafenib

BACKGROUND

This study describes a repeated measures prediction index to identify patients at high risk of ≥grade 2 hand-foot skin reaction (HFSR) before each week of sorafenib therapy.

METHODS

Data from 451 patients who received a sorafenib (400 mg bid) as part of a clinical trial were reviewed (Escudier B, Eisen T, Stadler WM et al. Sorafenib in advanced clear-cell renal-cell carcinoma. N Engl J Med 2007; 356: 125-134). Generalized estimating equations were used to develop the final risk model. A risk-scoring algorithm (range 0-58) was then derived from the final model coefficients. External validation was then carried out on a new sample of 1145 patients who received sorafenib under an expanded access program.

RESULTS

Pretreatment white blood cell count, female gender, good performance status, presence of lung and liver metastases and number of affected organs were predictors for ≥grade 2 HFSR. A nonlinear association between HFSR risk and treatment duration was also identified where risk was maximized at week 5 followed by a gradual decline. Before each week of therapy, patients with risk scores>40 would be considered at high risk for developing ≥grade 2 HFSR.

CONCLUSIONS

The application and planned continued refinement of this prediction tool will be an important source of patient-specific risk information for the development of moderate to severe HFSR.

A defensin-like peptide from Phaseolus vulgaris cv. 'King Pole Bean'

A 5447 Da antifungal peptide with an N-terminal sequence highly homologous to plant defensins was purified from Phaseolus vulgaris cv. 'King Pole Bean' by anion-exchange chromatography on Q Sepharose and FPLC-gel filtration on Superdex 75. The isolated peptide inhibited growth of a number of fungal species, including Mycosphaerella arachidicola, Saccharomyces cerevisiae and Candida albicans, with IC(50) values of 3.9, 4.0 and 8.4 μM, respectively. Using the membrane non-permeable DNA-binding dye SYTOX green, it was found that the peptide increased the cell membrane permeability of M. arachidicola, S. cerevisiae and C. albicans.

Clinical potential of DAS181 for treatment of parainfluenza-3 infections in transplant recipients

Parainfluenza virus (PIV) infections can cause serious respiratory infections and death in immunocompromised patients. No antiviral agents have proven efficacy against PIV, and therapy generally consists of supportive care. DAS181, a novel sialidase fusion protein that temporarily disables airway epithelial PIV receptors by enzymatic removal of sialic acid moieties, has been shown to inhibit infection with PIV strains in vitro and in an animal model. We describe here the clinical course of 2 immunocompromised patients with PIV-3 infection, one with a history of lung transplantation and the other neutropenic after autologous hematopoietic stem cell transplantation for multiple myeloma. Both patients had substantial clinical improvement in respiratory and systemic symptoms after a 5-day DAS181 treatment course, although the clinical improvement in the autologous stem cell transplantation patient also paralleled neutrophil engraftment.