Towards candidate genes affecting body fatness at the SSC7 QTL by expression analyses.

A quantitative trait locus (QTL) affecting fatness in a way opposite to expectations based on breed means was mapped to swine chromosome 7 (SSC7) using crosses between Large White (LW) and Meishan (MS) founders. Defining the molecular fatness trait more explicitly would allow deducing positional candidate genes, for which expression differences must be analysed in experimental populations. First, mRNA levels of genes representing sequential steps in adipogenesis or involved in lipid metabolism were studied in backfat of pigs having homozygous LW(QTL7)/LW(QTL7) or heterozygous LW(QTL7)/MS(QTL7) alleles and considered at two ages. mRNA level of DLK1 expressed in preadipocytes was greater in MS(QTL7)/LW(QTL7) pigs than in homozygous pigs at 28 days. Transcript abundances of CEBPA involved in differentiation, the prolipogenic FASN gene and the adipocyte-specific marker FABP4 were lower in MS(QTL7)/LW(QTL7) pigs compared with LW(QTL7)/LW(QTL7) pigs at 150 days. Because these results suggest a lag time in terminal differentiation associated with the MS allele, seven genes in the QTL interval were deduced as promising candidates for the QTL effect by bioinformatics analysis. Among them, PPARD and CDKN1A had lower expression levels in MS(QTL7)/LW(QTL7) pigs at both ages. Genotype-related differences were observed in mRNA levels of PPARD target genes involved in cell differentiation (FZD7) or fatty acid oxidation (ACADL and ACOX1) at 150 days. These results re-evaluate the potential of PPARD to explain part of variation in pig adiposity.

Evaluation of early regenerative processes in a preclinical pig model of acute kidney injury.

Renal failure due to ischemic injury is a common denominator of various clinical situations in critically ill patients. This study was designed to characterize the TPSO/Cholesterol synthesis and cell division pathways in response to different levels of ischemia. Porcine kidneys were subjected to either 60 min-warm ischemia (WI) or auto-transplanted after cold storage for 24 h at 4°C (CS), or both conditions (WI+CS), pathway activation and function were evaluated at 3 h, 3 and 7 days after reperfusion. CS combined to WI affects renal functions indicating a high degree of injury. During the first week of reperfusion, renal levels of free and esterified cholesterol, major cellular components, increased in CS group with an attenuated production when WI was associated. CS and WI+CS groups exhibited an elevated expression of cell cycle induction markers such as PCNA and stathmin. TSPO expression was highest in groups with the lowest injury, and correlated with kidney outcome, revealing its potential for diagnosis.

Epigenetic and genetic disturbance of the imprinted 11p15 region in Beckwith-Wiedemann and Silver-Russell syndromes.

Genomic imprinting is a particularly attractive example of epigenetic regulation leading to the parental-origin-specific expression of genes. In several ways, the 11p15 imprinted region is an exemplary model for regulation of genomic imprinting. The two imprinted domains are controlled by imprinting control regions (ICRs) which carry opposite germ line imprints and they are regulated by two major mechanisms of imprinting control. Dysregulation of 11p15 genomic imprinting results in two fetal growth disorders [Silver-Russell (SRS) and Beckwith-Wiedemann (BWS) syndromes], with opposite growth phenotypes. BWS and SRS result from abnormal imprinting involving either, both domains or only one of them, with ICR1 and ICR2 more often involved in SRS and BWS respectively. DNA methylation defects affecting ICR1 or ICR2 account for approximately 60% of SRS and BWS patients. Recent studies have identified new cis-acting regulatory elements, as well as new trans-acting factors involved in the regulation of 11p15 imprinting, therefore establishing new mechanisms of BWS and SRS. Those studies also showed that, apart of CTCF, other transcription factors, including factors of the pluripotency network, play a crucial role in the regulation of 11p15 genomic imprinting. Those new findings have direct consequences in molecular testing, risk assessment and genetic counseling of BWS and SRS patients.

Epigenetic and genetic mechanisms of abnormal 11p15 genomic imprinting in Silver-Russell and Beckwith-Wiedemann syndromes.

Fetal growth is a complex process depending on the genetics of the fetus, the availability of nutrients to the fetus, maternal nutrition and various growth factors and hormones of maternal, fetal and placental origin. The IGF system, and more particularly IGF2, is one of the most important endocrine and paracrine growth systems regulating fetal and placental growth (reviewed in [1]). The IGF2 gene is regulated by genomic imprinting and is expressed only from the paternally-inherited allele in most tissues during fetal development and after birth. Imprinted genes are tightly regulated and are therefore particularly susceptible to changes, including environmental and nutritional changes. Dysregulation of a cluster of imprinted genes, including the IGF2 gene within the 11p15 region, results in two fetal growth disorders (Silver-Russell and Beckwith-Wiedemann syndromes) with opposite growth phenotypes. Those two syndromes are model imprinting disorders to decipher the regulation of genomic imprinting.

Effect of polyethylene glycol-based preservation solutions on graft injury in experimental kidney transplantation.

BACKGROUND: New preservation solutions are emerging, of various ionic compositions and with hydroxyethyl starch replaced by polymers such as polyethylene glycols (PEGs), offering the potential for 'immunocamouflage'. This experimental study investigated which of three clinically available preservation protocols offered the best graft protection, based on epithelial-to-mesenchymal transition (EMT) and fibrosis. METHODS: Kidneys were preserved for 24 h at 4° C with University of Wisconsin solution (UW)as standard, compared with solutions containing either 1 g/l PEG 35 kDa (Institute Georges Lopez solution, IGL) or 30 g/l PEG 20 kDa (solution de conservation des organes et des tissus, SCOT). Animals were followed for up to 3 months and development of EMT, tubular atrophy and fibrosis was evaluated in comparison with sham-operated animals. RESULTS: Functional recovery was better in the SCOT group compared with the other groups. Chronic fibrosis, EMT and inflammation were observed in the UW and IGL groups, but limited in the SCOT group. Levels of profibrosis markers such as transforming growth factor ß1, plasminogen activator inhibitor 1 and connective tissue growth factor were increased in IGL and UW groups compared with the SCOT group. Hypoxia-inducible factor (HIF) 1α and 2α expression was increased at 3 months in grafts preserved in UW and IGL, but detected transiently on day 14 when SCOT was used. Expression of HIF-regulated genes vascular endothelial growth factor and erythropoietin was increased in UW and IGL groups. CONCLUSION: The choice of colloid and ionic content is paramount in providing long-term protection against chronic graft injury after renal transplantation. Preservation solutions based on PEGs may optimize graft quality.

QTL for resistance to Salmonella carrier state confirmed in both experimental and commercial chicken lines.

The ability of chickens to carry Salmonella without displaying disease symptoms is responsible for Salmonella propagation in poultry stocks and for subsequent human contamination through the consumption of contaminated eggs or meat. The selection of animals more resistant to carrier state might be a way to decrease the propagation of Salmonella in poultry stocks and its transmission to humans. Five QTL controlling variation for resistance to carrier state in a chicken F(2) progeny derived from the White Leghorn inbred lines N and 6(1) had been previously identified using a selective genotyping approach. Here, a second analysis on the whole progeny was performed, which led to the confirmation of two QTL on chromosomes 2 and 16. To assess the utility of these genomic regions for selection in commercial lines, we tested them together with other QTL identified in an [Nx6(1)] x N backcross progeny and with the candidate genes SLC11A1 and TLR4. We used a commercial line divergently selected for either low or high carrier-state resistance both in young chicks and in adult hens. In divergent chick lines, one QTL on chromosome 1 and one in the SLC11A1 region were significantly associated with carrier-state resistance variations; in divergent adult lines, one QTL located in the major histocompatibility complex on chromosome 16 and one in the SLC11A1 region were involved in these variations. Genetic studies conducted on experimental lines can therefore be of potential interest for marker-assisted selection in commercial lines.

Exclusion of the swine leukocyte antigens as candidate region and reduction of the position interval for the Sus scrofa chromosome 7 QTL affecting growth and fatness.

Pig chromosome 7 (SSC 7) has been shown to be rich in QTL affecting performance and quality traits. Most studies mapped the QTL close to the swine leukocyte antigens (SLA), which has a large effect on adaptability and natural selection. Previous comparative mapping studies suggested that the 15-cM region limited by markers LRA1 (mapped at 55 cM) and S0102 (mapped at 70 cM) contains hundreds of genes. To decrease the number of candidate genes, we improved the mapping resolution with a genetic chromosome dissection through a backcross recombinant progeny test program between Meishan (MS) and European (EU; i.e., Large White or Landrace) breeds. Three first-generation backcross--(EU x MS) x EU--and two second-generation backcross--([EU x MS] x EU) x EU--sires carrying a recombination in the QTL mapping interval were progeny-tested (i.e., measured for a total of 44 growth, fatness, carcass and meat quality traits). Progeny family size varied from 29 to 119 pigs. Animals were genotyped for markers covering the region of interest. Progeny-test results allowed the QTL interval to be decreased from 15 to 20 cM down to 10 cM, and even less than 6 cM if we assumed that the EU pigs used in this study share only one QTL allele. Except for a putative QTL affecting some carcass composition traits, the SLA is excluded as a candidate region, suggesting that it might be possible to apply a marker-assisted selection strategy for this QTL, while controlling SLA allele diversity. The strong QTL effects remaining in animals with only 12.5% (issued from first-generation backcross boars) and 6.25% (issued from second-generation back-cross boars) Meishan genetic background shows that epistatic interactions are likely to be limited. Finally, the QTL does not have strong effects on meat quality traits.

Lower extremity hypothermia is beneficial during infra-renal aortic cross-clamping in pigs.

The effects of lower extremity hypothermia during aortic cross-clamping are unknown. To compare the effects of lower extremity hypothermia with normothermia during aortic cross-clamping, two groups of six (25-40 kg) anesthetized pigs had their aortas cross-clamped below the renal arteries for 2 h. The cold group had their lower extremities cooled during cross-clamping to a quadriceps muscle temperature of 28 degrees C by using convective cooling. The warm group had the quadriceps muscle temperature maintained at 38 degrees C with convective warming. Saline, 0.9%, was used to maintain the pulmonary capillary wedge pressures at 5 mm Hg in both groups. Reperfusion of the lower extremities resulted in a small but significant decrease in the blood temperature from 36.6 +/- 0.3 degrees C (mean +/- SE) to 35.6 +/- 0.3 degrees C 1 min after reperfusion in the cold group, but did not change the blood temperature in the warm group. Both the cardiac output and the lower extremity arterial flow were greater in the cold group at 1 and 5 min after cross-clamp release. Also one pig in the warm group required resuscitation with 1 mg of epinephrine intravenously to treat severe hypotension and myocardial depression after cross-clamp release. We conclude that hypothermia of the lower extremities may be beneficial for surgery involving aortic cross-clamping.

Duodenal perforation in blunt abdominal trauma.

Ten patients with duodenal perforation secondary to blunt abdominal trauma are reviewed. All 10 patients survived. Most of the injuries were related to motor vehicle accidents. Early recognition requires a high index of suspicion because preoperative signs and symptoms tend to be nonspecific and x-rays are usually not helpful. A careful exploration of the duodenum at laparotomy including both the Kocher maneuver and the Cattell-Braasch exposure is essential. Suitable methods of surgical repair are numerous, but those providing for restoration of normal gastrointestinal tract continuity are preferred.