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Purpose: Recently, dietary supplementation with inorganic nitrate (NO3-) has been proposed to endurance athletes to increase their performance. However, it has been suggested that an excess of NO3- might be harmful. The present study analyzed the effect of NO3- supplementation on kidney function. Methods: Thirteen young male subjects performed a 20-min cycling exercise at 85% of the maximal oxygen capacity. Seven days before exercise, the subjects ingested either a placebo (PI) or 450 mg of potassium nitrate (PN) per day. Venous blood samples and urine collections were collected before and immediately after exercise and after 60 min of recovery. Glomerular filtration rates (GFR) and clearances (Cl) were calculated from serum content and urine output for creatinine (Cm), albumin (Alb), and urea. Results: Under resting conditions, GFR and all clearance measures did not differ between PI and PN. Immediately after exercise, GFR remained stable in both PI and PN, whereas Cl-urea decreased significantly (P < 0.05) in PI (-44%) and PN (-49%). Alb urine outputs were enhanced by 18- to 20-fold in PI and PN, respectively (P < 0.05). After the recovery period, GFR remained enhanced under PI conditions, whereas Cl-urea returned to initial values in placebo and nitrate supplementation. Alb output and Cl-Alb remained enhanced under PN conditions. Conclusion: These results mainly indicate that dietary nitrate supplementation over a week does not induce any specific kidney function modifications either at rest or during sustained submaximal exercise as compared with PL [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article about the effect of inorganic nitrate supplementation on renal function before and after exercise by A. Carpentier et al. in the previous issue.

Background-Undersized ring annuloplasty for ischemic mitral regurgitation (MR) is associated with variable results and >30% MR recurrence. We tested whether subvalvular repair by severing second-order mitral chordae can improve annuloplasty by reducing papillary muscle tethering. Methods and Results-Posterolateral myocardial infarction known to produce chronic remodeling and MR was created in 28 sheep. At 3 months, sheep were randomized to sham surgery versus isolated undersized annuloplasty versus isolated bileaflet chordal cutting versus the combined therapy (n = 7 each). At baseline, chronic myocardial infarction (3 months), and euthanasia (6.6 months), we measured left ventricular (LV) volumes and ejection fraction, wall motion score index, MR regurgitation fraction and vena contracta, mitral annulus area, and posterior leaflet restriction angle (posterior leaflet to mitral annulus area) by 2-dimensional and 3-dimensional echocardiography. All groups were comparable at baseline and chronic myocardial infarction, with mild to moderate MR (MR vena contracta, 4.6±0.1 mm; MR regurgitation fraction, 24.2±2.9%) and mitral annulus dilatation (P<0.01). At euthanasia, MR progressed to moderate to severe in controls but decreased to trace with ring plus chordal cutting versus trace to mild with chordal cutting alone versus mild to moderate with ring alone (MR vena contracta, 5.9±1.1 mm in controls, 0.5±0.08 with both, 1.0±0.3 with chordal cutting alone, 2.0±0.4 with ring alone; P<0.01). In addition, LV end-systolic volume increased by 108% in controls versus 28% with ring plus chordal cutting, less than with each intervention alone (P<0.01). In multivariate analysis, LV end-systolic volume and mitral annulus area most strongly predicted MR (r2=0.82, P<0.01). Conclusions-Comprehensive annular and subvalvular repair improves long-term reduction of both chronic ischemic MR and LV remodeling without decreasing global or segmental LV function at follow-up [ABSTRACT FROM AUTHOR]

Purpose: It has been claimed that oral creatine supplementation might have potential cytotoxic effects on healthy consumers by increasing the production of methylamine and formaldehyde. Despite this allegation, there has been no scientific evidence obtained in humans to sustain or disprove such a detrimental effect of this widely used ergogenic substance. Methods: Twenty young healthy men ingested 21 g of creatine monohydrate daily for 14 consecutive days. Venous blood samples and 24-h urine were collected before and after the 14th day of supplementation. Creatine and creatinine were analyzed in plasma and urine, and methylamine, formaldehyde, and formate were determined in 24-h urine samples. Results: Oral creatine supplementation increased plasma creatine content 7.2-fold (P < 0.001) and urine output 141-fold (P < 0.001) with no effect on creatinine levels. Twenty-four-hour urine excretion of methylamine and formaldehyde increased, respectively, 9.2-fold (P = 0,001) and 4.5-fold (P = 0.002) after creatine feeding, with no increase in urinary albumin output (9.78 ± 1.93 mg.24 h-1 before, 6.97 ± 1.15 mg.24 h-1 creatine feeding). Conclusion: This investigation shows that short-term, high-dose oral creatine supplementation enhances the excretion of potential cytotoxic compounds, but does not have any detrimental effects on kidney permeability. This provides indirect evidence of the absence of microangiopathy in renal glomeruli. [ABSTRACT FROM AUTHOR]

Introduction: After 10 years of implantation, 20 to 30% of valvular bioprosthesis show signs of dysfunction mostly due to calcification. Hypothesis: Because of bioprosthesis valve endothelial recovery after implantation is link to hemocompatibility and non-thrombogenicity, we hypothesis that a disruption of endothelial recovery associated to a modification of endothelial/angiogenic circulating marker could be associated with valve bioprosthesis degeneration. Methods: This is a retrospective case-control study based on serum from 74 adult patients with degeneration of valve bioprosthesis operated in two academic centers between 1998 and 2016. The control group included 50 age- and gender-matched subjects without valve diseases. Levels of VEGF-A, PDGF-BB, Thrombospondin-1 (TSP-1), soluble endoglin (sENG), TGF-β1, soluble protein C endothelial receptor (sEPCR), soluble E-selectin and ultra-sensitive CRP were measured in all subjects. Results: A total of 74 patients with degenerative valve biosprothesis were included. The average age of patients was 60.3 years and 68.9% were men. Among patients 74.3% had a redux valvular surgery and 35 (47.3%) had a calcified bioprosthesis explanted. Median age of patients at implantation and median biosprothesis life expectancy were respectively 46.3 years and 13.7 years. There was no significant difference between the clinical characteristics and cardiovascular risk factors of patients with or without calcification of the explanted bioprosthesis. The univariate analysis showed significant decrease in VEGF-A (p=0.011), TSP-1 (p=0.048) and sEPCR levels (p=0.006) in patients with calcified bioprosthesis. After adjustment, only a level of sEPCR lower than 108 ng/mL was significantly associated with a risk of calcification of the degenerative bioprosthesis (OR: 0.2, 95% CI 0.03-0.41, p<0.001). Conclusions: The novel evidence of a possible value of the sEPCR as a biomarker of valve bioprosthesis calcification was presented. Our results suggested a link between endothelial marker, coagulation and calcification of bioprosthetic valve. [ABSTRACT FROM AUTHOR]