High sodium intake is associated with important risk factors in a large cohort of chronic kidney disease patients.

BACKGROUND/OBJECTIVES: An increased risk of mortality and cardiovascular disease (CVD) is observed in people with chronic kidney disease (CKD) even in early stages. Dietary sodium intake has been associated with important CVD and CKD progression risk factors such as hypertension and proteinuria in this population. We aimed to investigate the relationship between sodium intake and CVD or CKD progression risk factors in a large cohort of patients with CKD stage 3 recruited from primary care. SUBJECTS/METHODS: A total of 1733 patients with previous estimated glomerular filtration rate (eGFR) of 30-59 ml/min/1.73m(2), with a mean age 72.9±9.0 years, were recruited from 32 general practices in primary care in England. Medical history was obtained and participants underwent clinical assessment, urine and serum biochemistry testing. Sodium intake was estimated from three early-morning urine specimens using an equation validated for this study population. RESULTS: Sixty percent of participants who had estimated sodium intake above recommendation (>100 mmol/day or 6 g salt/day) also had higher diastolic blood pressure, mean arterial pressure (MAP), urinary albumin-to-creatinine ratio, high-sensitive C-reactive protein and uric acid and used a greater number of anti-hypertensive drugs. In multivariable regression analysis, excessive sodium intake was an independent predictor of MAP (B=1.57, 95% confidence interval (CI) 0.41-2.72; P=0.008) and albuminuria (B=1.35, 95% CI 1.02-1.79; P=0.03). CONCLUSIONS: High sodium intake was associated with CVD and CKD progression risk factors in patients with predominantly early stages of CKD followed up in primary care. This suggests that dietary sodium intake could afffect CVD risk even in early or mild CKD. Intervention studies are warranted to investigate the potential benefit of dietary advice to reduce sodium intake in this population.

QTL for yield and associated traits in the Seri/Babax population grown across several environments in Mexico, in the West Asia, North Africa, and South Asia regions.

Heat and drought adaptive quantitative trait loci (QTL) in a spring bread wheat population resulting from the Seri/Babax cross designed to minimize confounding agronomic traits have been identified previously in trials conducted in Mexico. The same population was grown across a wide range of environments where heat and drought stress are naturally experienced including environments in Mexico, West Asia, North Africa (WANA), and South Asia regions. A molecular genetic linkage map including 475 marker loci associated to 29 linkage groups was used for QTL analysis of yield, days to heading (DH) and to maturity (DM), grain number (GM2), thousand kernel weight (TKW), plant height (PH), canopy temperature at the vegetative and grain filling stages (CTvg and CTgf), and early ground cover. A QTL for yield on chromosome 4A was confirmed across several environments, in subsets of lines with uniform allelic expression of a major phenology QTL, but not independently from PH. With terminal stress, TKW QTL was linked or pleiotropic to DH and DM. The link between phenology and TKW suggested that early maturity would favor the post-anthesis grain growth periods resulting in increased grain size and yields under terminal stress. GM2 and TKW were partially associated with markers at different positions suggesting different genetic regulation and room for improvement of both traits. Prediction accuracy of yield was improved by 5 % when using marker scores of component traits (GM2 and DH) together with yield in multiple regression. This procedure may provide accumulation of more favorable alleles during selection.

Heat and drought adaptive QTL in a wheat population designed to minimize confounding agronomic effects.

A restricted range in height and phenology of the elite Seri/Babax recombinant inbred line (RIL) population makes it ideal for physiological and genetic studies. Previous research has shown differential expression for yield under water deficit associated with canopy temperature (CT). In the current study, 167 RILs plus parents were phenotyped under drought (DRT), hot irrigated (HOT), and temperate irrigated (IRR) environments to identify the genomic regions associated with stress-adaptive traits. In total, 104 QTL were identified across a combination of 115 traits × 3 environments × 2 years, of which 14, 16, and 10 QTL were associated exclusively with DRT, HOT, and IRR, respectively. Six genomic regions were related to a large number of traits, namely 1B-a, 2B-a, 3B-b, 4A-a, 4A-b, and 5A-a. A yield QTL located on 4A-a explained 27 and 17% of variation under drought and heat stress, respectively. At the same location, a QTL explained 28% of the variation in CT under heat, while 14% of CT variation under drought was explained by a QTL on 3B-b. The T1BL.1RS (rye) translocation donated by the Seri parent was associated with decreased yield in this population. There was no co-location of consistent yield and phenology or height-related QTL, highlighting the utility of using a population with a restricted range in anthesis to facilitate QTL studies. Common QTL for drought and heat stress traits were identified on 1B-a, 2B-a, 3B-b, 4A-a, 4B-b, and 7A-a confirming their generic value across stresses. Yield QTL were shown to be associated with components of other traits, supporting the prospects for dissecting crop performance into its physiological and genetic components in order to facilitate a more strategic approach to breeding.