Overexpression of angiotensin-converting enzyme 2 in the rostral ventrolateral medulla causes long-term decrease in blood pressure in the spontaneously hypertensive rats

The rostral ventrolateral medulla (RVLM) is a relay point that provides supraspinal excitatory input to sympathetic preganglionic neurons in the regulation of blood pressure. The importance of the RVLM is further highlighted by observations that an increase of RVLM sensitivity to angiotensin II and enhanced sympathetic activity are associated with hypertension. Angiotensin-converting enzyme 2 (ACE2) has been shown to be central in maintaining the balance between vasoconstrictor activity of angiotensin II with vasoprotective action of angiotensin-(1-7) in the peripheral system. However, its role in central control of blood pressure in the RVLM is yet to be investigated. Thus, our objective in this study was to compare ACE2 expression in the RVLM of Wistar-Kyoto rats and spontaneously hypertensive rats and to determine whether RVLM ACE2 is involved in blood pressure control. ACE2 immunoreactivity was diffusely distributed in many cardiovascular regulatory neurons, including the RVLM. Western blot analysis revealed a 40% decrease in ACE2 in the RVLM of spontaneously hypertensive rat compared with Wistar-Kyoto rats. Lentiviral-mediated overexpression of ACE2 (lenti-ACE2) was used to determine whether a decrease in ACE2 in the RVLM is associated with hypertensive state. Bilateral injection of lenti-ACE2 resulted in a long-term expression of transgenic ACE2. This was associated with a decrease in mean arterial pressure exclusively in the spontaneously hypertensive rat (141+/-4 mm Hg in lenti-GFP versus 124+/-5 mm Hg in lenti-ACE2) and heart rate (304+/-7 bpm in lenti-GFP versus 285+/-5 bpm in lenti-ACE2). These observations demonstrate that overexpression of ACE2 overcomes its intrinsic decrease in the RVLM and decreases high blood pressure in the spontaneously hypertensive rat.     

Association of anemia and physical disability among patients with rheumatoid arthritis

OBJECTIVE: To evaluate the relationship between hemoglobin concentration and physical disability in patients with rheumatoid arthritis (RA). METHODS: Data were derived from 2495 patients with RA enrolled in 3 clinical trials (ATTRACT, ASPIRE, and START) and treated with infliximab (3 to 10 mg/kg) plus methotrexate (MTX), or MTX plus placebo. The association of hemoglobin and the Health Assessment Questionnaire (HAQ) score was assessed at baseline (n = 2471) and Week 22 (n = 2458) by Spearman correlation, and multivariate linear regression models were employed to control for confounding effects from demographic and other clinical variables. A logistic regression model was used to estimate the odds ratio (OR) for a clinically meaningful improvement (> or = 0.25 point increase) in HAQ associated with a > or = 1 g/dl improvement in hemoglobin from baseline at Week 22. RESULTS: About 37% of patients with RA had anemia based on World Health Organization criteria: hemoglobin < 12 g/dl in women (39%) and < 13 g/dl in men (32%). Low hemoglobin level was significantly associated with more severe physical disability at baseline (p < 0.001), and both male and female patients with anemia had more severe disability at baseline. Improvement in hemoglobin after treatment at Week 22 was an independent contributor to improvement in HAQ, and a > or = 1 g/dl improvement in hemoglobin after treatment was associated with a clinically meaningful improvement in the HAQ score at Week 22 (OR 1.43, 95% CI 1.10-1.86; p < 0.01). CONCLUSION: Anemia is one of the independent factors contributing to physical disability in patients with RA. Improvement in anemia following effective RA treatment may play an independent role in improving physical function.     

Study of thiobarbituric reactive substances and total reduced glutathione as indices of oxidative stress in chronic smokers with and without chronic obstructive pulmonary disease

BACKGROUND: The imbalance between oxidants and antioxidants is thought to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). METHODS: Biomarkers of lipid oxidation such as thiobarbituric reactive substances (TBARs), total reduced glutathione (GSH) were estimated in chronic smokers with and without COPD, and non-smokers. RESULTS: The following subjects (all males) were studied: (i) chronic smokers (32.5 +/- 8.6 pack years) with stable COPD (n = 20; mean age 47.2 +/- 7.8 years); (ii) chronic smokers (6.3 +/- 1.9 pack years) without COPD (n = 20; mean age 35.3 +/- 4.5 years); and (iii) non-smokers (n = 20; mean age 37.5 +/- 5.5 years). The mean TBARs levels (nmol of malondialdehyde per ml of plasma) were higher among smokers with COPD (5.72 +/- 1.02) when compared with smokers without COPD (4.85 +/- 0.97) and non-smokers (2.58 +/- 0.56) (p < 0.001). The mean GSH levels (micromol/mg of protein) were significantly higher in non-smokers (0.163 +/- 0.113) compared to smokers with COPD (0.083 +/- 0.05) and those without COPD (0.050 +/- 0.051) (p < 0.001). There was no statistically significant difference in the plasma GSH levels among smokers with and without COPD (p > 0.05). CONCLUSIONS: Our observations demonstrate increased lipid peroxidation because of oxidative stress due to smoking.     

Bacterial endotoxin: a trigger factor for alcoholic pancreatitis? Evidence from a novel, physiologically relevant animal model

BACKGROUND & AIMS: This study examined the possible role of endotoxinemia (from increased gut permeability) as an additional trigger factor for overt pancreatic disease and as a promoter of chronic pancreatic injury in alcoholics by using a rat model of chronic alcohol feeding and in vitro experiments with cultured pancreatic stellate cells (PSCs), the key mediators of pancreatic fibrosis. METHODS: In the in vivo model, Sprague-Dawley rats fed isocaloric Lieber-DeCarli liquid diets +/- alcohol for 10 weeks were challenged with a single dose or 3 repeated doses of the endotoxin lipopolysaccharide (LPS) and the pancreas was examined. In the in vitro studies, rat PSCs were assessed for activation on exposure to LPS +/- ethanol. The expression of LPS receptors TLR4 and CD14 also was assessed in rat and human PSCs. RESULTS: In the in vivo model, single or repeated LPS challenge resulted in significantly greater pancreatic injury in alcohol-fed rats compared with rats fed the control diet without alcohol. Notably, repeated LPS injections caused pancreatic fibrosis in alcohol-fed rats, but not in rats fed the control diet. In the in vitro studies, PSCs were activated by LPS. Alcohol + LPS exerted a synergistic effect on PSC activation. Importantly, both rat and human PSCs expressed TLR4 and CD14. CONCLUSIONS: This study describes, for the first time, a clinically relevant animal model of alcohol-related pancreatic injury and provides strong in vivo and in vitro evidence that suggests that LPS is a trigger factor in the initiation and progression of alcoholic pancreatitis.     

Application of sensitive enzymeimmunoassay for determination of cortisol in blood plasma of yaks (Poephagus grunniens L.)

As an alternative to radioimmunoassays, a simple, highly sensitive and quick enzymeimmunoassay (EIA) for determination of cortisol in blood plasma of yaks on microtiterplates using second antibody coating technique and cortisol-horseradish peroxidase as a label has been developed. The wells of the microtiterplate were coated with affinity-purified goat IgG (antirabbit IgG) that binds the hormone specific antibody. The EIA was carried out directly in 20 microl of heat treated plasma after 1:5 dilution with PBS. The cortisol standard curve, with doses ranged from 0.4 to 100 pg/well. The sensitivity of the assay was 20 pg/ml. Cortisol standard curve in buffer showed parallelism with serially diluted yak plasma containing high endogenous cortisol. Intra- and inter-assay coefficients of variation (CV) determined using pooled plasma was found 6.58 and 11.35%, respectively. Recovery of known concentrations of added cortisol in charcoal stripped plasma was linear (r = 0.98). For biological validation of cortisol enzymeimmunoassay, the blood samples were collected from yak cows at -48 and -24h before and 0, 12, 24, 36, 48, 60, 72, 84 and 96 h after dexamethasone administration. The plasma cortisol before dexamethasone administration was significantly (P < 0.05) higher than after dexamethasone administration. The developed EIA was further validated biologically by estimating cortisol in peri-parturient cows beginning day 10 prior to calving till day 10 post-calving; the concentrations were along with the expected lines as reported in bovine. In conclusion, the EIA developed in this study is simple, highly sensitive, valid and sufficiently reliable method for estimation of cortisol directly in bovine plasma.     

A pilot study showing an association between platelet hyperactivity and the severity of peripheral arterial disease

Peripheral arterial disease (PAD) is a chronic fibroproliferative inflammatory condition associated with progressive vascular stenosis. We set out to determine the relationship between spontaneous stirring-induced platelet aggregation in whole blood and the severity of lower-limb PAD, represented by the ankle-brachial pressure index (ABPI). ABPI was determined pre- and post-exercise in 31 subjects (20 men and 11 women) with established PAD. Platelets counts were determined in EDTA blood (total count) and in citrated whole blood after stirring in the absence of added ADP (spontaneous aggregation) and in the presence of added ADP (ADP-induced) for 3 min at 37 degrees C. Aggregation was calculated as a percentage of the total platelet count. Spontaneous platelet aggregation showed an inverse correlation with pre-exercise ABPI (r = -0.32; P < 0.05) and ADP-induced aggregation correlated inversely with post-exercise ABPI (r = -0.34; P < 0.05). These results indicate that platelet hyperactivity is associated with increasing severity of PAD. Increased platelet aggregation may result in thromboembolic events in the affected limb.     

Juvenile rheumatic mitral stenosis with multiple ventricular septal defects

Congenital heart disease is related to events occurring in the embryonal stage, while rheumatic heart disease is a sequela of immune-mediated damage following streptococcal infection. We report an unusual association of multiple ventricular septal defects and severe pulmonary arterial hypertension with rheumatic mitral stenosis in a 7-year-old girl. This case highlights the need for careful examination for coexisting rheumatic disease in late presentations of congenital heart disease.