PubMed Health⌕ Search

Biomedical subjects

Drahomíra Krenová

Publications and source records attributed to Drahomíra Krenová.

6 recordsLinked to original sources

Sucrose feeding during pregnancy and lactation elicits distinct metabolic response in offspring of an inbred genetic model of metabolic syndrome.

The importance of early environment, including maternal diet during pregnancy, is suspected to play a major role in pathogenesis of metabolic syndrome and related conditions. One of the proposed mechanisms is a mismatch between the prenatal and postnatal environments, leading to misprogramming of the metabolic and signaling pathways of the developing fetus. We assessed whether the exposure to high-sucrose diet (HSD) alleviates the detrimental effects of sucrose feeding in later life (predictive adaptive hypothesis) in a highly inbred model of metabolic syndrome, the PD/Cub rat. Rat dams were continuously fed either standard or HSD (70% calories as sucrose) starting 1 wk before breeding, throughout pregnancy, at birth, and until weaning of the offspring. After weaning, all male offspring were fed HSD until the age of 20 wk, when detailed metabolic and morphometric profiles were ascertained. The early life exposure to a sucrose-rich diet resulted in distinct responses to longtime postnatal HSD feeding. Offspring of the sucrose-fed mothers displayed higher adiposity and substantial increases in triglyceride liver content together with unfavorable distribution of cholesterol into lipoprotein subfractions. On the other hand, their adiponectin concentrations were significantly higher, and insulin sensitivity of skeletal muscle was enhanced compared with the offspring of standard diet-fed mothers. Triglycerides, free fatty acids, overall glucose tolerance, and the insulin sensitivity of adipose tissue were comparable in both groups. In the genetically identical animals, maternal HSD feeding elicited a variety of subtle effects but did not lead to predictive adaptive protection from most HSD-induced metabolic derangements.

Animals↗

Novel double-congenic strain reveals effects of spontaneously hypertensive rat chromosome 2 on specific lipoprotein subfractions and adiposity.

We have developed a new, double-congenic rat strain BN-Lx.SHR2, which carries two distinct segments of chromosome 2 introgressed from the spontaneously hypertensive rat strain (SHR) into the genetic background of congenic strain BN-Lx, which was previously shown to express variety of metabolic syndrome features. In 16-wk-old male rats of BN-Lx and BN-Lx.SHR2 strains, we compared their glucose tolerance and triacylglycerol and cholesterol concentrations in 20 lipoprotein subfractions and the lipoprotein particle sizes under conditions of feeding standard and high-sucrose diets. Introgression of two distinct SHR-derived chromosome 2 segments resulted in decreased adiposity together with aggravation of glucose intolerance in the double-congenic strain. The BN-Lx.SHR2 rats were more sensitive to sucrose-induced rise in triacylglycerolemia. Although the total cholesterol concentrations of the two strains were comparable after the standard diet and even lower in BN-Lx.SHR2 after sucrose feeding, detailed analysis revealed that under both dietary conditions, the double-congenic strain had significantly higher cholesterol concentrations in low-density lipoprotein fractions and lower high-density lipoprotein fractions. We established a new inbred model showing dyslipidemia and mild glucose intolerance without obesity, attributable to specific genomic regions. For the first time, the chromosome 2 segments of SHR origin are shown to influence other than blood pressure-related features of metabolic syndrome or to be involved in relevant nutrigenomic interactions.

Adipose Tissue↗

Altered spermatogenesis in the hypodactylous rats.

Germinal epithelium of seminiferous tubules in adult, infertile hypodactylous males displays significant reduction in the number of germ-line cells. Detection of apoptosis in the germ-line cells during postnatal differentiation was performed to elucidate the mechanism of the decreased number of germ cells in the testes of adult rats. Evaluation of DNA fragmentation and expression of activated caspase-3 in germ cells did not confirm marked germ cell death during the onset of spermatogenesis as a main cause of significant reduction of germ cells in Hd/Hd testes of adult males. The primary cause of spermatogenesis defect seems to be rather associated with a disorder in the cell cycle regulation and interrelation of germ-line cells with Sertoli cells.

Animals↗

A new framework marker-based linkage map and SDPs for the rat HXB/BXH strain set.

A new contiguous genetic linkage map of the HXB/BXH set of rat recombinant inbred (RI) strains was constructed to enhance QTL mapping power and precision, and thereby make the RI strain set a better genomics resource. The HXB/BXH rat RI strains were developed from a cross between the hypertensive SHR/OlaIpcv and normotensive BN- Lx/Cub rat strains and have been shown useful for identifying quantitative trait loci (QTL) for a variety of cardiovascular, metabolic, and behavioral phenotypes. In the current analysis, the DNAs from 31 existing strains, 1 substrain, and 4 extinct strains were genotyped for a selection of polymorphic microsatellite marker loci, predominantly polymorphic framework markers from high-density integrated rat genome maps. The resulting linkage map consists of 245 microsatellite markers spanning a total length of 1789 cM with an average inter-marker distance of ~8.0 cM. This map covers the rat genome contiguously and completely with the exception of two locations on Chromosomes (Chrs) 11 and 16. The new genotypic information obtained also permitted further genetic characterization of the RI strain set including strain independence, genetic similarity among the individual strains, and non-syntenic associations between loci.

Alleles↗

Genetic map of AFLP markers in the rat (Rattus norvegicus) derived from the H x B/Ipcv and B x H/Cub sets of recombinant inbred strains.

The amplified fragment length polymorphism (AFLP) technique has been used to enhance marker density in a large set of recombinant inbred strains (H x B and B x H) derived from a spontaneously hypertensive rat (SHR/OlaIpcv) and a Brown-Norway (BN.lx/Cub) inbred strain. Thirteen different primer combinations were tested and a total of 191 polymorphic bands were detected. From these polymorphic bands 89 AFLP markers could be assigned to specific chromosomes. Several of these AFLP markers were mapped to regions with low marker density, thus filling up gaps in the existing genetic map of these recombinant inbred strains. These results substantiate the value of the AFLP technology in increasing marker density in genetic maps.

Animals↗

Identification and chromosomal localization of ecogenetic components of electrolyte excretion.

OBJECTIVE: To determine to what extent urinary excretion of blood pressure-modulating electrolytes is genetically determined, and to identify their chromosomal localization. DESIGN AND METHODS: Twenty-six rat recombinant inbred strains (RIS) originating from reciprocal crosses of normotensive Brown Norway (BN.Lx) and spontaneously hypertensive rats (SHR) were used. A pilot experiment on a subset of strains determined that fasting decreases the impact of environmental noise and increases that of heritability. Twenty-four-hour urinary collections were obtained from fasting rats aged 6-12 weeks (3-8 rats per strain). Sodium (Na), potassium (K) and calcium (Ca) excretions were measured, and the Na/K ratio calculated. These phenotypes served as quantitative traits for the search of quantitative trait loci (QTLs) by scanning the RIS genome that was mapped with 475 polymorphic markers. RESULTS: Constant Na intake resulted in a low heritability for Na excretion, reflecting the environmental impact (intake = excretion), whereas fasting revealed a gradient among RIS indicative of the genetic component of the traits. In the fasting state, a locus on chromosome 14 was found to be significantly associated with K excretion (Alb, P = 0.00002, r = -0.69, logarithm of the odds score (LOD) 3.9), whereas another locus on chromosome 10 (D10Cebrp97s5, P = 0.0003, r = -0.69, LOD 3.0) and one on chromosome 6 (D6Cebrp97s14, P = 0.0007, r = -0.65, LOD 1.9) were more significantly associated with Na excretion and the Na/K ratio respectively. The observed correlations were all negative for Na, K and Na/K, indicating a higher excretion of Na and K and a greater Na/K ratio in rats bearing BN.Lx alleles at these loci, i.e. salt retention in fasting SHR. These three loci accounted for 47-55% of variance of their associated trait, suggesting that they are the main genetic determinants for these phenotypes in basal fasting conditions. Rats bearing the Y chromosome of SHR origin had significantly higher K excretion that, in turn, led to a significantly lower Na/K ratio. Finally, a locus on chromosome 7 was linked to Ca excretion, explaining 46% of the trait variance (D7Mit10, LOD score 3.0). CONCLUSION: RIS enabled us to determine QTLs for environmentally modulated traits such as Na, K and Ca excretions. We demonstrated that whereas urinary electrolytes are determined mainly by intake (environment) in a steady state, their excretion in an adaptive state (fasting) is predominantly genetically determined by distinct QTL on autosomes as well as the Y chromosome. Furthermore, the loci responsible for Na and K excretions act independently of the locus governing the relative excretion of Na/K. Thus, the salt-retaining aspects of some hypertensives may be, in large part, determined by genes responsible for renal excretion, the impact of which is predominant over the environment under acute challenge.

Age Factors↗