Synergistic antifungal activity and potential mechanism of action of a glycolipid-like compound produced by Streptomyces blastmyceticus S108 against Candida clinical isolates.

AIM: The present study aimed to investigate a novel antifungal compound produced by Streptomyces blastmyceticus S108 strain. Its effectiveness against clinical isolates of Candida species and its synergistic effect with conventional antifungal drugs were assessed, and its molecular mechanism of action was further studied against Candida albicans. METHODS AND RESULTS: A newly isolated strain from Tunisian soil, S. blastmyceticus S108, showed significant antifungal activity against Candida species by well diffusion method. The butanolic extract of S108 strain supernatant exhibited the best anti-Candida activity with a minimal inhibitory concentration (MIC) value of 250 µg ml-1, determined by the microdilution method. The bio-guided purification steps of the butanolic extract were performed by chromatographic techniques. Among the fractions obtained, F13 demonstrated the highest level of activity, displaying a MIC of 31.25 µg ml-1. Gas chromatography-mass spectrometry and electrospray ionization mass spectrometry analyses of this fraction (F13) revealed the glycolipidic nature of the active molecule with a molecular weight of 685.6 m/z. This antifungal metabolite remained stable to physicochemical changes and did not show hemolytic activity even at 4MIC corresponding to 125 µg ml-1 toward human erythrocytes. Besides, the glycolipid compound was combined with 5-flucytosine and showed a high synergistic effect with a fractional inhibitory concentration index value 0.14 against C. albicans ATCC 10231. This combination resulted in a decrease of MIC values of 5-flucytosine and the glycolipid-like compound by 8- and 64-fold, respectively. The examination of gene expression in treated C. albicans cells by quantitative polymerase chain reaction (qPCR) revealed that the active compound tested alone or in combination with 5-flucytosine blocks the ergosterol biosynthesis pathway by downregulating the expression of ERG1, ERG3, ERG5, ERG11, and ERG25 genes. CONCLUSION AND IMPACT OF THE STUDY: The new glycolipid-like compound, produced by Streptomyces S108 isolate, could be a promising drug for medical use against pathogenic Candida isolates.

Early Development of Cardiac Fibrosis in Young Old-Father Offspring.

Cardiac aging is characterized by progressive fibrosis. Epidemiological studies have found that advanced paternal age is associated with an increased risk of heart failure in the next generation. This study is aimed at evaluating the effect of paternal age, in the young male rat progeny, on cardiac phenotype under circulatory stress conditions. Offspring rats were obtained by mating old males (24 months old) with young females (two months old) and by mating young males (two months old) with the same young females. Hypertension was induced in old father offspring (OFO) rats and young old father (YFO) offspring rats using L-NAME (N(ω)-nitro-L-arginine methyl ester). The OFO L-NAME rats showed a high blood pressure phenotype associated with substantial cardiac hypertrophy and an exacerbation of cardiac fibrosis compared to the YFO L-NAME rats. Histological analysis of heart tissue showed an expansion of the extracellular matrix, with fibroblasts displaying markers of epicardial origin (Tcf21, Tbx18, and Wt1) in the OFO group. Moreover, western blot and protein phosphorylation antibody array identified the TGF-ß2 receptor pathway as preferentially activated in aged hearts as well as in OFO cardiac tissue treated with L-NAME. In addition, old father offspring rats (OFO+OFO L-NAME) had increased cardiac DNA methylation. In young hypertensive progeny, advanced paternal age at conception may be a risk factor for early progression towards cardiac fibrosis. An intergenerational transmission may be behind the paternal age-related cardiac remodeling in the young offspring.

Ultra-Performance Liquid Chromatographic and Densitometric Methods for Sensitive Determination of Xipamide and Triamterene in Pure and Pharmaceutical Dosage Forms.

BACKGROUND: Validated ultra-performance liquid chromatography (UPLC) and thin-layer chromatography (TLC) densitometric methods were prescribed for determination of antihypertensive components. OBJECTIVE: To establish and validate rapid and accurate UPLC and TLC densitometric methods for determination of Xipamide and Triamterene in pure and dosage forms. METHODS: The first method, UPLC, depended on using an Agilent Zorbax Eclipse Plus C8 (50 mm × 2.1 mm, 1.8 µm) column, a mobile phase composed of acetonitrile-water (70 + 30, v/v) adjusted by acetic acid to obtain pH 3, 0.2 mL/min flow rate, and UV detection at 231.4 nm. The second method was a TLC densitometric method. Separation was achieved by using toluene-methanol-ethyl chloride-acetic acid (7 + 2 + 1 + 0.2, v/v/v) as the mobile phase, pre coated silica gel plates as the stationary phase, and UV detection at 300.0 nm. RESULTS: The obtained results were validated and statistically compared with official and reported methods. The obtained results showed high accuracy and reproducible results with excellent mean recoveries for both drugs. CONCLUSION: The UPLC method showed shorter retention time for both Xipamide (0.88 min) and Triamterene (0.63 min), a lower detection limit of less than 0.055 µg/mL for both drugs with high selectivity, decreased injection volume (1 µL), and a lower flow rate than any HPLC method. Both proposed methods were sensitive, selective, and effectively applied to pure and dosage forms (Epitens®). HIGHLIGHTS: Unprecedented sensitive, rapid, and reproducible UPLC and TLC methods were developed for selective determination of mixtures of Xipamide and Triamterene, with LOD os less than 0.076 µg/mL for both drugs.

Impact of the strategy for curative treatment of synchronous colorectal cancer liver metastases.

AIM OF THE STUDY: Fourteen to seventeen percent of patients suffering from colorectal cancer have synchronous liver metastases (sCRLM) at the time of diagnosis. There are currently three possible strategies for curative management of sCRLM: "classic", "combined", and "liver-first". The aim of our research was to analyze the effects of the three surgical management strategies for sCRLM on postoperative morbidity and mortality and overall and recurrence-free survival. PATIENTS AND METHODS: Patients treated for sCRLM between October 2000 and May 2015 were included. We defined three groups: (1) "classic": surgery of primary tumor and then surgery of sCRLM; (2) "combined": combined surgery of primary tumor and sCRLM: and (3) "liver-first": surgery of sCRLM and then surgery of primary tumor. RESULTS: During this period, 170 patients who underwent 209 hepatectomies were included ("classic": 149, "combined": 34, "liver-first": 26). The rate of severe complications was higher in the "combined" group compared to the "classic" group (35% vs. 12%, P=0.03), and the "liver-first" group (35% vs. 19%, P=0.25), while there were significantly fewer liver resections. Overall survival at 5 years in our cohort was 46%, without significant differences between the groups, and a median survival of 54 months. Recurrence-free survival of the patients in our cohort was 24% at 5 years, with a median survival time without recurrence of 14 months, without significant differences between the groups. CONCLUSION: All three strategies were feasible and there were no differences regarding overall and recurrence-free survivals between the three approaches. The "combined" strategy group had significantly more severe complications and did not provide better oncological results, despite less aggressive liver disease and more limited liver resections.

Beneficial role of simvastatin in experimental autoimmune myositis.

OBJECTIVE: Statins have immunomodulatory potential in autoimmune diseases but had not been studied as a disease-modifying agent in inflammatory myopathies. The objective of this study is to assess the effect of simvastatin in an experimental model of autoimmune myositis in mice on muscle strength and histopathology. METHODS: Four groups of mice (n = 5 per group) were selected for experimentally induced myositis. Mice were immunized with 1.5 mg myosin in complete Freund's adjuvant weekly for two times and injected with 500 ng pertussis toxin twice immediately after each immunization. From day 1 before immunization to 10 days after the last immunization, mice were treated with oral simvastatin (10 or 20 or 40 mg/kg) diluted in DMSO. The control group mice were injected with complete Freund's adjuvant weekly for two times and did not receive treatment. Non-immunized mice (n = 5 per group) were treated either with simvastatin (5 mg/kg or 20 mg/kg or 40 mg/kg of simvastatin diluted in DMSO) or with DMSO. RESULTS: Inflammation was observed in myositis groups with positive myositis-specific antibodies. Muscle strength dropped significantly after immunization. Immunized simvastatin 20 mg/kg treated group had significantly higher muscle strength versus non-treated myositis mice and versus other simvastatin doses. Besides, a trend toward higher serum Th17 percentage population was found in immunized non-treated mice, versus immunized simvastatin- treated mice, without significant difference. CONCLUSION: Simvastatin at 20 mg/kg decreases the severity of myositis in experimental autoimmune myositis and is a candidate of being a disease-modifying agent in inflammatory myopathies.

Intradialytic hypotension: beyond hemodynamics.

Intradialytic hypotension is a major complication during hemodialysis session, associated with increased risk of cardiovascular events and mortality. Its pathophysiology is believed to be multifactorial and remains not well elucidated. The aim of this study is to put forward new mechanisms behind the development of intradialytic hypotension. The study included sixty-five subjects on chronic hemodialysis, divided into two groups: intradialytic hypotensive (n=12) and normotensive (n=53), according to the variation of systolic blood pressure between post-dialysis and pre-dialysis measurements. Renin and angiotensin converting enzyme I plasma concentrations increased in both groups but more likely in normotensive group. Aldosterone plasma concentration is increased in the normotensive group while it decreased in the intradialytic hypotension group. Plasma endothelin concentrations showed higher values in intradialytic hypotension group. Post-dialysis asymmetric dimethylarginine and angiotensin converting enzyme 2 plasma concentrations were significantly higher in intradialytic hypotension group as compared to normotensive one. Collectrin plasma concentrations were significantly lower in intradialytic hypotension group. Finally, post-dialysis vascular endothelial growth factor C plasma concentration significantly increased in intradialytic hypotension group. In conclusion, endothelial dysfunction characterized by a lower level of vasoactive molecule seems to play a critical role in intradialytic hypotension development.

Original Study: Transjugular Intrahepatic Portosystemic Shunt as a Bridge to Abdominal Surgery in Cirrhotic Patients.

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) has been suggested to reduce portal hypertension-associated complications in cirrhotic patients undergoing abdominal surgery. The aim of this study was to compare postoperative outcome in cirrhotic patients with and without specific preoperative TIPS placement, following elective extrahepatic abdominal surgery. METHODS: Patients were retrospectively included from 2005 to 2016 in four centers. Patients who underwent preoperative TIPS (n = 66) were compared to cirrhotic control patients without TIPS (n = 68). Postoperative outcome was analyzed using propensity score with inverse probability of treatment weighting analysis. RESULTS: Overall, colorectal surgery accounted for 54% of all surgical procedure. TIPS patients had a higher initial Child-Pugh score (6[5-12] vs. 6[5-9], p = 0.043) and received more beta-blockers (65% vs. 22%, p < 0.001). In TIPS group, 56 (85%) patients managed to undergo planned surgery. Preoperative TIPS was associated with less postoperative ascites (hazard ratio = 0.330 [0.140-0.780]). Severe postoperative complications (Clavien-Dindo > 2) and 90-day mortality were similar between TIPS and no-TIPS groups (18% vs. 23%, p = 0.392, and 7.5% vs. 7.8%, p = 0.644, respectively). CONCLUSIONS: Preoperative TIPS placement yielded an 85% operability rate with satisfying postoperative outcomes. No significant differences were found between TIPS and no-TIPS groups in terms of severe postoperative complications and mortality, although TIPS patients probably had worse initial portal hypertension.

Univariate calibrations with or without chemometric assistance for determination of drugs lacking peak maxima in their zero-order profiles.

Trandolapril has no sharp peak in its zero-order spectrum and therefore, it is difficult to be measured by direct spectrophotometry. In this manuscript, several univariate and multivariate spectrophotometric methods were developed and validated for determination of Trandolapril (TR) and Verapamil (VR) combination. The first method for measuring Trandolapril is Constant Multiplication-Spectrum Subtraction (CM-SS), where Trandolapril was measured at 210 nm in its zero-order curve after elimination of Verapamil spectrum. Second and third methods are two Base Points (2BP) and area under the curve (AUC) to measure Trandolapril concentration without depending on the shoulder peak. The fourth method for Trandolapril is Derivative Subtraction (DS) that utilizes the sharp peak appeared in the first order spectrum of Trandolapril. Verapamil was determined by two methods, Constant Multiplication (CM) and Derivative Subtraction-Constant Multiplication (DS-CM). Also, two multivariate methods were developed for measurement of the mixture, Partial Least Squares (PLS) and Principal Component Regression (PCR). All the developed methods were validated as per ICH guidelines and the results proved that the developed methods are accurate and selective. Moreover, a statistical comparison between the developed methods and a reference method was done. Also, One-way ANOVA statistical test was done between all the proposed univariate and multivariate spectrophotometric methods.

Determination of amlodipine and atorvastatin mixture by different spectrophotometric methods with or without regression equations.

Four new, simple, and reproducible spectrophotometric methods were developed and validated for the simultaneous determination of Amlodipine (AML) and Atorvastatin (AT) in bulk powder and pharmaceutical dosage form. The four methods include two progressive and two successive resolution techniques. The two progressive methods are Absorbance Subtraction (AS) and Amplitude Modulation (AM), while the two successive methods are Constant Value (CV) and Concentration Value. In the Concentration Value method, the concentration of the drugs is determined from the graphical representation without the use of regression equations. Linearity range for the two progressive methods was from 5 µg/mL-35 µg/mL while for the two successive methods was from 5 µg/mL-55 µg/mL. The four methods were validated according to the ICH guidelines and were found to be accurate, precise, and selective. The methods were also applied for determination of the mixture in the marketed pharmaceutical dosage form. Results obtained were compared with reported methods. Also, One-way ANOVA statistical test was done between all the proposed spectrophotometric methods where no significant differences were found.

Mimicking new receptors based on molecular imprinting and their application to potentiometric assessment of 2,4-dichlorophenol as a food taint.

Innovative host-tailored polymers were prepared, characterized and used as recognition elements in potentiometric transducers for the selective quantification of 2,4-dichlorophenol (DCP).The polymer beads were synthesized using DCP as a template molecule, acrylamide (AM),methacrylic acid (MAA) and ethyl methacrylate (EMA) as functional monomers and divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDMA) as cross-linkers. The sensors were fabricated by the inclusion of MIPs in plasticized polyvinyl chloride (PVC) matrix. Response characteristics of the proposed sensors revealed anionic slopes of -59.2, -49.7 and -80.6 mV/decade with detection limits of 5.6 × 10-5,5.9 × 10-5 and 13.2 × 10-5 mol/L for MIP/AM/DVB, MIP/MAA/DVB and MIP/EMA/EGDMA membrane based sensors, respectively. Good selectivity was observed over common inorganic/organic anions. Validation of the assay method according to IUPAC recommendations was justified ensuring the synthesis of good reliable novel sensors for DCP determination. The method was successfully applied for routine analysis of food taint in fish and fish farms water samples.

[The effect of methylphenidate on appetite and weight]. / L'effet de la méthylphénidate sur l'appétit et le poids.

OBJECTIVES: To better delineate in the medical literature the effect of methylphenidate on weight and appetite. METHODS: A search on PubMed was carried out for articles published with no restrictions on language or year of publication using the terms: "methylphenidate"; "weight"; "appetite". RESULTS: Methylphenidate increases dopamine and noradrenaline in synapses because of its blockage of the transporters of these monoamines in the frontal cortex and insular lobe. The intracerebral activity of methylphenidate is incriminated in the dysregulation of appetite due to its probable effect stimulating the disgust sensation generated after the activation of the insular lobe by the drug. The anorexigenic effect of methylphenidate has been demonstrated in preclinical studies although the dosage and the administration routes differ in animals from those used for human beings. In clinical studies, methylphenidate decreases the weight of children and adolescents during the first 3 to 6 months after its initiation due to the appetite reduction effect that it generates with a tendency of weight curves to rejoin the curves of subjects who did not receive the treatment a few years after its initiation. CONCLUSION: The anorexigenic effect of methylphenidate does not persist over the long-term in children and adolescents who receive it.

DNA demethylation induces SALL4 gene re-expression in subgroups of hepatocellular carcinoma associated with Hepatitis B or C virus infection.

Sal-like protein 4 (SALL4), an embryonic stem cell transcriptional regulator, is re-expressed by an unknown mechanism in poor prognosis hepatocellular carcinoma (HCC), often associated with chronic hepatitis B virus (HBV) infection. Herein, we investigated the mechanism of SALL4 re-expression in HBV-related HCCs. We performed bisulfite sequencing PCR of genomic DNA isolated from HBV-related HCCs and HBV replicating cells, and examined DNA methylation of a CpG island located downstream from SALL4 transcriptional start site (TSS). HBV-related HCCs expressing increased SALL4 exhibited demethylation of specific CpG sites downstream of SALL4 TSS. Similarly, SALL4 re-expression and demethylation of these CpGs was observed in HBV replicating cells. SALL4 is also re-expressed in poor prognosis HCCs of other etiologies. Indeed, increased SALL4 expression in hepatitis C virus-related HCCs correlated with demethylation of these CpG sites. To understand how CpG demethylation downstream of SALL4 TSS regulates SALL4 transcription, we quantified by chromatin immunoprecipitation (ChIP) assays RNA polymerase II occupancy of SALL4 gene, as a function of HBV replication. In absence of HBV replication, RNA polymerase II associated with SALL4 exon1. By contrast, in HBV replicating cells RNA polymerase II occupancy of all SALL4 exons increased, suggesting CpG demethylation downstream from SALL4 TSS influences SALL4 transcriptional elongation. Intriguingly, demethylated CpGs downstream from SALL4 TSS are within binding sites of octamer-binding transcription factor 4 (OCT4) and signal transducer and activator of transcription3 (STAT3). ChIP assays confirmed occupancy of these sites by OCT4 and STAT3 in HBV replicating cells, and sequential ChIP assays demonstrated co-occupancy with chromatin remodeling BRG1/Brahma-associated factors. BRG1 knockdown reduced SALL4 expression, whereas BRG1 overexpression increased SALL4 transcription in HBV replicating cells. We conclude demethylation of CpGs located within OCT4 and STAT3 cis-acting elements, downstream of SALL4 TSS, enables OCT4 and STAT3 binding, recruitment of BRG1, and enhanced RNA polymerase II elongation and SALL4 transcription.

Increasing obesity rates in school children in United Arab Emirates.

BACKGROUND: The remarkable socioeconomic changes in United Arab Emirates (UAE) necessitate regular monitoring of obesity in our population. This study explored the epidemiology of obesity in a large cohort of UAE students. METHODS: This population-based study investigated the prevalence of obesity in 44,942 students attending governmental schools in Ras Al-Khaimah. Body-mass-index (BMI) was calculated in 15,532 children (4-12 y) in 2013-2014, and in 29,410 children (3-18 y) in 2014-2015. The International Obesity Task Force, World Health Organization, and Centers for Disease Control (CDC) reference methods were used to identify overweight, obesity, and extremely-obesity. RESULTS: Using CDC interpretation of BMI, from 11 to 14 y, the prevalence of BMI ≥85th percentile was 41.2%, BMI ≥95th percentile 24.3% and BMI ≥99th percentile 5.7%. Obesity increased linearly from 3 to 12 y (R2 ≥ 0.979); each year an additional 2.36% of the students became obese and 0.28% became extremely obese. The rate of extreme-obesity was 9.6-fold higher in boys than girls (0.58% vs. 0.06%). From 15 to 18 y, 10.3% of boys were extremely obese and 3.0% of girls were extremely obese. CONCLUSIONS: These results confirm a steady rise in obesity in children 3-18 y. The rising rate of extreme obesity is also alarming, especially among boys.

Optimization of Extraction, HPLC and Kinetic Studies for Determination of Some Food Tainting Compounds in Different Food Matrices.

Solid-liquid extraction, ultrasonic-assisted extraction and matrix solid-phase dispersion (MSPD) were optimized and compared in terms of recoveries for the simultaneous extraction of indole (IND) and 2,4-dichlorophenol (DCP) from catfish samples and for the extraction of IND alone from potato samples. Applying high-performance liquid chromatography (HPLC-DAD) procedure using mobile phase of methanol : water (65 : 35) at 280 nm, MSPD was the method of choice for the extraction of IND and DCP from catfish and, also, for IND from potato. The extraction recoveries of MSPD were in the range (97.9-99.7%) and (99.8-100.6%); for IND and DCP, respectively, in catfish samples and (98.4-99.7%) for IND alone in potato samples. Solid-phase extraction (SPE) was chosen the method of choice for the extraction of DCP from fish farms water samples after optimization and comparison with direct sample injection and extraction recoveries were in the range (97.9-100.3%). Kinetics were further studied to follow each of production of IND in catfish during storage at different temperatures and uptake of DCP by tilapia in fish farms water samples using MSPD-HPLC and SPE-HPLC, respectively.

Effects of atrial natriuretic peptide on rat ventricular fibroblasts during differentiation into myofibroblasts.

Atrial natriuretic peptide antifibrotic properties are mainly described in cardiac myocytes or in induced cardiac myofibroblasts (Angiotensin II or TGF-beta induced differentiation). In the present work, we investigate the effects of ANP/NPRA/cGMP system in modulating rat cardiac fibroblasts function. Cardiac fibroblasts were isolated from adult Wistar male rats and cultured in the presence of serum in order to induce fibroblasts differentiation. Cultures were then treated with ANP (1 microM), 8-Br-cGMP (100 microM) or IBMX (100 microM), a non-specific phosphodiesterases inhibitor. ANP significantly decreased proliferation rate and collagen secretion. Its effect was mimicked by the cGMP analog, while combining ANP with 8-Br-cGMP did not lead to additional effects. Moreover intracellular cGMP levels were elevated when cells were incubated with ANP confirming that ANP intracellular pathway is mediated by cGMP. Additionally, immunoblotting and immunofluorescence were used to confirm the presence of guanylyl cyclase specific natriuretic peptide receptors A and B. Finally we scanned specific cGMP dependent PDEs via RT-qPCR, and noticed that inhibiting all PDEs led to an important decrease in proliferation rate. Effect of ANP became more prominent after 10 culture days, confirming the importance of ANP in fibroblasts to myofibroblasts differentiation. Uncovering cellular aspects of ANP/NPRA/cGMP signaling system provided more elements to help understand cardiac fibrotic process.

Cardiorenal syndrome in hypertensive rats: microalbuminuria, inflammation and ventricular hypertrophy.

The aim of our study was to evaluate a possible association between microalbuminuria (MA), several low-grade inflammation factors and left ventricular hypertrophy (LVH) by using a pharmacological approach. This may provide new insights into the pathophysiologic mechanisms of the cardiorenal syndrome (CRS) linking early renal impairment with elevated cardiovascular risk. Two kidney-one clip (2K-1C) renovascular hypertension was induced in 24 male Wistar rats (220-250 g). After the development of hypertension, rats were divided into four groups: 2K-1C (untreated), calcium channel blocker (amlodipine-treated), angiotensin receptor blocker (losartan-treated) and peripheral vasodilator (hydralazine-treated), which were treated for 10 weeks. Rats in the 2K-1C group had all developed hypertension, a significant increase in plasma levels of tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), brain natriuretic peptide (BNP) and C-reactive protein (CRP). Moreover MA and creatininaemia underwent a significant increase. Under treatment decreases were observed in systolic blood pressure (SBP), TNF-alpha, CRP, IL-6, BNP concentrations and creatininaemia. These results were related to the absence of MA which was significantly associated with reductions in cardiac mass and hypertrophy markers (BNP and beta-MHC gene expression) as well as renal interstitial inflammation. In conclusion, our results suggest that the reduction of MA is correlated with the decrease of the inflammatory components and seems to play an important role in protecting against cardiac hypertrophy and renal injury.

[Maxillary bone sarcoidosis]. / Sarcoïdose osseuse maxillaire.

INTRODUCTION: Sarcoidosis is an unexplained systemic granulomatosis. Bone localizations of the disease are rare. We report a maxillary localization. CASE: A 35-year-old patient consulted for facial dysmorphia first observed 2 years before. This swelling was associated to nodular panniculitis lesions and xerostomia. The facial asymmetry was due to maxillary gingival and alveolar swelling. It was associated with scarring in the legs and a purple nodular facial lesion. Lip and jaw biopsies revealed epithelioid and giant cell granulomas without caseous necrosis. The panoramic dental X-ray showed diffuse horizontal alveolar ridge lysis and CT scan revealed an osteolytic lesion of the right maxilla associated to a bone-condensing lesion of the left hemi-mandible. DISCUSSION: The diagnosis of sarcoidosis is made in case of epithelioid and giant cell granulomas without caseous necrosis and the ruling out of other possible diagnoses, including tuberculosis. Bone involvement is rare; face and maxillary localization are extremely rare. The recommended treatment is corticosteroids. Facial remodeling surgery is not recommended.

Microalbuminuria versus brain natriuretic peptide in cardiac hypertrophy of hypertensive rats.

The objective of this study was to assess a possible link between microalbuminuria (MA), a major risk factor of the cardiorenal syndrome and the brain natriuretic peptide (BNP), a marker of cardiac hypertrophy. Two kidney-one clip (2K-1C) renovascular hypertension was induced in 24 male Wistar rats (weighing 220-250 g). Rats were randomized into four groups for 8 weeks: Sham, not treated; Bos, treated with bosentan; Cap, treated with captopril; Bos/Cap, treated with both drugs. Blood pressure, plasma BNP and transforming growth factor beta1 (TGF-ß1) concentrations, microalbuminuria and creatininemia as well as cardiac mass, BNP, alpha- and beta-myosin heavy chain (MHC) gene expression and kidney histology were determined. Following stenosis, Sham rats developed hypertension (p < 0.001), an increase in BNP (p < 0.05) and TGF-ß1 (p < 0.005) concentrations, creatinine levels (p < 0.001), and urinary albumin (p < 0.001). Under drug treatment, decreases in blood pressure (p < 0.001), creatinine levels (p < 0.05), plasma TGF-ß1 (p < 0.005) and BNP (p < 0.05) concentrations, were concomitant with the absence of MA which was significantly correlated with reductions in cardiac mass (p < 0.05) and hypertrophy markers (BNP and ß-MHC gene expression) (p < 0.005) as well as in renal fibrosis. These findings suggest a potential link between microalbuminuria evolution and BNP as well as a possible effect of microalbuminuria-lowering therapy on halting the progression, or even inducing the regression of cardiac hypertrophy.

B-type natriuretic peptide receptors in hypertrophied adult rat cardiomyocytes.

Brain natriuretic peptide (BNP) binds to three types of natriuretic peptide receptors, NPR-A, -B and -C (NPRs). The expression shape of BNP and NPRs seems to be an important modulator factor in the pathogenesis of cardiac hypertrophy. The aim of this study was to evaluate the expression of NPRs in an animal model of pressure overload hypertrophy. Left ventricular hypertrophy was induced by chronic abdominal aortic banding in adult male Wistar rats. After six weeks, NPRs gene expression was evaluated with RT-PCR, BNP plasma concentration and BNP positive myocytes were measured with ELISA and immunohistochemistry techniques respectively. NPR-A and NPR-C mRNA expression was significantly increased in left ventricular hypertrophied cardiomyocytes by 1.6-fold and 2.1-fold respectively (P<0.01). Abdominal aortic banding increased significantly BNP plasma concentration (630+/-8pg/ml vs 106+/-4pg/ml; P<0.01). The percentage of BNP positive cells in normal myocardial tissue were 40% while in the hypertrophied one it raised to 80%. The data suggest that in our left ventricular hypertrophy model, the NPR-A and NPR-C receptors were increased in association to the increased BNP level. This relationship may amplify beneficial paracrine/autocrine effects of BNP on cardiac remodelling in response to hemodynamic overload.