Amelioration of Systemic Fibrosis in Mice by Angiotensin II Receptor Blockade

Objective

Systemic sclerosis (SSc) is characterized by microvascular damage, fibrosis of skin and visceral organs, and autoimmunity. Previous studies have shown that angiotensin II is involved in the synthesis of type I collagen. We investigated whether the blockade of angiotensin II receptor type I (AT₁) by irbesartan reduces skin and lung fibrosis in 2 murine models of SSc.

Methods

SSc was induced by daily intradermal injection of HOCl into the backs of BALB/c mice (HOCl‐induced SSc). Mice were treated daily with irbesartan by oral gavage.

Results

Irbesartan reduced dermal thickness, collagen concentration, Smad2/3, and α‐smooth muscle actin expression, as well as fibroblast proliferation and H‐Ras expression in the skin of mice with HOCl‐induced SSc. Mice treated with irbesartan also displayed less lung fibrosis, less inflammation, and a lower concentration of collagen in the lungs than untreated mice. Exhaled nitric oxide, inducible nitric oxide synthase, and 3‐nitrotyrosine expression in the lungs were decreased following irbesartan treatment. Moreover, irbesartan reduced the number and the proliferation of splenic B and T cells and the serum levels of anti–DNA topoisomerase I autoantibodies.

Conclusion

Irbesartan, an AT₁ antagonist, prevents fibrosis and inflammation and inhibits nitric oxide production in HOCl‐induced models of systemic fibrosis. Our findings extend the indication of an AT₁ antagonist to SSc patients with diffuse fibrosis, especially those with lung involvement.

     

Body build and body proportions in children with bronchial asthma

This paper is a literature review of somatic development in children with chronic bronchial asthma. Asthma is the most common chronic inflammatory disease of the respiratory system in children and youth that is increasing in prevalence. In spite of significant progress in treatment, growth problems are often observed in children with asthma. Growth delay in asthmatic children, increased incidence of short stature, distorted body proportions and nutritional status impairment are reported frequently, in spite of inhaled corticosteroid drugs treatment. The severity of the asthma influences growth outcomes. The issue of growth in children with chronic asthma requires further detailed studies in its clinical and auxological aspects.     

The mTOR/AKT inhibitor temsirolimus prevents deep infiltrating endometriosis in mice

Deep infiltrating endometriosis (DIE) is a particular clinical and histological entity of endometriosis responsible for chronic pelvic pain and infertility. Here we characterize the proliferative phenotype of DIE cells, to explore the cellular and molecular mechanisms that could explain their aggressive potential. In addition, the inhibition of mTOR/AKT pathway was tested, as a potential treatment of DIE. Included were 22 patients with DIE and 12 control patients without endometriosis. Epithelial and stromal cells were extracted from biopsies of eutopic endometrium and deep infiltrating endometriotic nodules from patients with DIE. Cell proliferation was determined by thymidine incorporation. Oxidative stress was assayed by spectrofluorometry. The ERK and mTOR/AKT pathways were analyzed in vitro by Western blot and for AKT in vivo in a mouse model of DIE. The proliferation rate of eutopic endometrial cells and of deep infiltrating endometriotic cells from DIE patients was higher than that of endometrial cells from controls. The hyperproliferative phenotype of endometriotic cells was associated with an increase in endogenous oxidative stress, and with activation of the ERK and mTOR/AKT pathways. mTOR/AKT inhibition by temsirolimus decreased endometriotic cell proliferation both in vitro and in vivo in a mouse model of DIE. Blocking the mTOR/AKT pathway offers new prospects for the treatment of DIE.     

Clopidogrel protects from cell apoptosis and oxidative damage in a mouse model of renal ischaemia-reperfusion injury

Renal ischaemia-reperfusion injury (IRI) is consecutive to tissue oxidative damage and cell apoptosis that lead to acute renal failure (ARF) in renal allografts. The aim of this study was to investigate the beneficial effects of a pretreatment by clopidogrel on renal IRI in mice. IRI was induced by bilateral renal ischaemia for 45 min followed by reperfusion. Sixty-two healthy male BALB/c mice were randomly assigned to one of the following groups: PBS + ischaemia-reperfusion (IR); clopidogrel + IR; PBS + sham IR; clopidogrel + sham IR. Clopidogrel (25 mg/kg) or PBS was administered per os to the animals via a gastric cannula 24 h before operation. All mice were given a single dose of clopidogrel or PBS. Renal function histological damage, renal cell apoptosis, renal antioxidant activities, and CD41 expression were determined 24 h after reperfusion. The survival rates were evaluated over 7 days. Animals pretreated with clopidogrel had lower plasma levels of blood urea nitrogen (BUN) and creatinine, lower histopathological scores, and improved survival rates following IR. Renal cell apoptosis induced by IR was decreased in kidneys of mice pretreated by clopidogrel, with an increase in Bcl-2 and Bcl-xL expression and a decrease in caspase-3, caspase-8, and Bax expression. Renal reduced glutathione, superoxide dismutase, and catalase activities were unmodified by the pretreatment with clopidogrel. However, clopidogrel resulted in an increased total antioxidant capacity of the kidney. Furthermore, pretreatment by clopidogrel decreased the number of CD41-positive cells. Thus, clopidogrel exerts protective effects on renal IRI in mice by abrogating renal cell apoptosis as a consequence of improved renal antioxidant capacity and could be tried as a novel therapeutic tool in renal IRI.     

Comparison of human erythrocyte purine nucleotide metabolism and blood purine and pyrimidine degradation product concentrations before and after acute exercise in trained and sedentary subjects

This study aimed at evaluating the concentration of erythrocyte purine nucleotides (ATP, ADP, AMP, IMP) in trained and sedentary subjects before and after maximal physical exercise together with measuring the activity of purine metabolism enzymes as well as the concentration of purine (hypoxanthine, xanthine, uric acid) and pyrimidine (uridine) degradation products in blood. The study included 15 male elite rowers [mean age 24.3 ± 2.56 years; maximal oxygen uptake (VO_2max) 52.8 ± 4.54 mL/kg/min; endurance and strength training 8.2 ± 0.33 h per week for 6.4 ± 2.52 years] and 15 sedentary control subjects (mean age 23.1 ± 3.41 years; VO_2max 43.2 ± 5.20 mL/kg/min). Progressive incremental exercise testing until refusal to continue exercising was conducted on a bicycle ergometer. The concentrations of ATP, ADP, AMP, IMP and the activities of adenine phosphoribosyltransferase (APRT), hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and phosphoribosyl pyrophosphate synthetase (PRPP-S) were determined in erythrocytes. The concentrations of hypoxanthine, xanthine, uric acid and uridine were determined in the whole blood before exercise, after exercise, and 30 min after exercise testing. The study demonstrated a significantly higher concentration of ATP in the erythrocytes of trained subjects which, in part, may be explained by higher metabolic activity on the purine re-synthesis pathway (significantly higher PRPP-S, APRT and HGPRT activities). The ATP concentration, just as the ATP/ADP ratio, as well as an exercise-induced increase in this ratio, correlates with the VO_2max level in these subjects which allows them to be considered as the important factors characterising physical capacity and exercise tolerance. Maximal physical exercise in the group of trained subjects results not only in a lower post-exercise increase in the concentration of hypoxanthine, xanthine and uric acid but also in that of uridine. This indicates the possibility of performing high-intensity work with a lower loss of not only purine but also pyrimidine.     

HLA-C C1C2 heterozygosity may protect women bearing the killer immunoglobulin-like receptor AA genotype from spontaneous abortion

Spontaneous abortion is the most common complication of human pregnancy. Natural killer (NK) cells expressing killer immunoglobulin-like receptors (KIRs), which may recognize HLA-C (i.e. its C1 or C2 groups) on trophoblast cells, constitute a large leukocyte population in the endometrium. This study investigated whether genetic polymorphisms in the KIR and HLA-C genes are risk factors for spontaneous abortion. One hundred and twenty-five couples with at least two spontaneous abortions, including eighty-five couples with idiopathic recurrent abortion (RSA; three or more abortions), and 117 control couples (with two or more healthy-born children) were tested. The frequencies of the individual KIR genes in the patients were similar to those in the controls. In the group of KIR AA women with HLA-C C2C2 partners, the HLA-C C1C2 heterozygotes were present in the controls but not in the patients (p=0.015 for all patients and p=0.0048 for RSA, but both comparisons lost significance after Bonferroni correction), whereas both homozygotes, C1C1 and C2C2, were absent in the control women but present among the aborting ones. Therefore, our results suggest that among KIR AA women who have HLA-C C2C2 partners, HLA-C heterozygous females show a trend towards an increased chance of successful pregnancy.     

Validation of GC method for quantitative determination of residual 2-(2-chloroethoxy)ethanol (CEE) and N-methyl-2-pyrrolidinone (NMP) in pharmaceutical active substance

The gas chromatography method with direct injection for quantitative determination of residual nonvolatile solvents such as 2-(2-chloroethoxy)ethanol (CEE) and N-methyl-2-pyrrolidinone (NMP) in quetiapine--the pharmaceutical active substance has been validated. Validation was performed according to the requirement of ICH validation guidelines Q2A and Q2B. Specificity, precision, accuracy, linearity, limits of detection and quantitation and robustness were determined and excellent results were obtained.     

The effects of N-terminal part modification of arginine vasopressin analogues with 2-aminoindane-2-carboxylic acid: a highly potent V2 agonist

In this study we present the synthesis and some pharmacological properties of nine new analogues of arginine vasopressin modified in the N-terminal part of the molecule with 2-aminoindane-2-carboxylic acid (Aic). The peptides were tested for their in vitro uterotonic and in vivo pressor and antidiuretic activities. One of the new peptides, [Mpa1,Aic2,Val4,D-Arg8]VP, exhibited an antidiuretic activity similar to that of [Mpa1,D-Arg8]VP, thus being one of the most potent antidiuretic vasopressin analogues reported to date.     

The organotelluride catalyst (PHTE)₂NQ prevents HOCl-induced systemic sclerosis in mouse

Systemic sclerosis (SSc) is a connective tissue disorder characterized by skin and visceral fibrosis, microvascular damage, and autoimmunity. HOCl-induced mouse SSc is a murine model that mimics the main features of the human disease, especially the activation and hyperproliferation rate of skin fibroblasts. We demonstrate here the efficiency of a tellurium-based catalyst 2,3-bis(phenyltellanyl)naphthoquinone ((PHTE)(2)NQ) in the treatment of murine SSc, through its selective cytotoxic effects on activated SSc skin fibroblasts. SSc mice treated with (PHTE)(2)NQ displayed a significant decrease in lung and skin fibrosis and in alpha-smooth muscle actin (α-SMA) expression in the skin compared with untreated mouse SSc animals. Serum concentrations of advanced oxidation protein products, nitrate, and anti-DNA topoisomerase I autoantibodies were increased in SSc mice, but were significantly reduced in SSc mice treated with (PHTE)(2)NQ. To assess the mechanism of action of (PHTE)(2)NQ, the cytotoxic effect of (PHTE)(2)NQ was compared in normal fibroblasts and in mouse SSc skin fibroblasts. ROS production is higher in mouse SSc fibroblasts than in normal fibroblasts, and was still increased by (PHTE)(2)NQ to reach a lethal threshold and kill mouse SSc fibroblasts. Therefore, the effectiveness of (PHTE)(2)NQ in the treatment of mouse SSc seems to be linked to the selective pro-oxidative and cytotoxic effects of (PHTE)(2)NQ on hyperproliferative fibroblasts.