Association of Common Polymorphisms in GLUT9 Gene with Gout but Not with Coronary Artery Disease in a Large Case-Control Study

BACKGROUND: Serum uric acid (UA) levels have recently been shown to be genetically influenced by common polymorphisms in the GLUT9 gene in two genome-wide association analyses of Italian and British populations. Elevated serum UA levels are often found in conjunction with the metabolic syndrome. Hyperuricemia is the major risk factor for gout and has been associated with increased cardiovascular morbidity and mortality. The aim of the present study was to further elucidate the association of polymorphisms in GLUT9 with gout and coronary artery disease (CAD) or myocardial infarction (MI). To test our hypotheses, we performed two large case-control association analyses of individuals from the German MI Family Study. METHODS AND FINDINGS: First, 665 patients with gout and 665 healthy controls, which were carefully matched for age and gender, were genotyped for four single nucleotide polymorphisms (SNPs) within or near the GLUT9 gene. All four SNPs demonstrated highly significant association with gout. SNP rs6855911, located within intron 7 of GLUT9, showed the strongest signal with a protective effect of the minor allele with an allelic odds ratio of 0.62 (95% confidence interval 0.52-0.75; p = 3.2*10(-7)). Importantly, this finding was not influenced by adjustment for components of the metabolic syndrome or intake of diuretics. Secondly, 1,473 cases with severe CAD or MI and 1,241 healthy controls were tested for the same four GLUT9 SNPs. The analyses revealed, however, no significant association with CAD or with MI. Additional screening of genome-wide association data sets showed no signal for CAD or MI within the GLUT9 gene region. CONCLUSION: Thus, our results provide compelling evidence that common genetic variations within the GLUT9 gene strongly influence the risk for gout but are unlikely to have a major effect on CAD or MI in a German population

Mutations in the SLC2A9 Gene Cause Hyperuricosuria and Hyperuricemia in the Dog

Allantoin is the end product of purine catabolism in all mammals except humans, great apes, and one breed of dog, the Dalmatian. Humans and Dalmatian dogs produce uric acid during purine degradation, which leads to elevated levels of uric acid in blood and urine and can result in significant diseases in both species. The defect in Dalmatians results from inefficient transport of uric acid in both the liver and renal proximal tubules. Hyperuricosuria and hyperuricemia (huu) is a simple autosomal recessive trait for which all Dalmatian dogs are homozygous. Therefore, in order to map the locus, an interbreed backcross was used. Linkage mapping localized the huu trait to CFA03, which excluded the obvious urate transporter 1 gene, SLC22A12. Positional cloning placed the locus in a minimal interval of 2.5 Mb with a LOD score of 17.45. A critical interval of 333 kb containing only four genes was homozygous in all Dalmatians. Sequence and expression analyses of the SLC2A9 gene indicated three possible mutations, a missense mutation (G616T;C188F) and two promoter mutations that together appear to reduce the expression levels of one of the isoforms. The missense mutation is associated with hyperuricosuria in the Dalmatian, while the promoter SNPs occur in other unaffected breeds of dog. Verification of the causative nature of these changes was obtained when hyperuricosuric dogs from several other breeds were found to possess the same combination of mutations as found in the Dalmatian. The Dalmatian dog model of hyperuricosuria and hyperuricemia underscores the importance of SLC2A9 for uric acid transport in mammals

Glucose Transporter 1 and Monocarboxylate Transporters 1, 2, and 4 Localization within the Glial Cells of Shark Blood-Brain-Barriers

Although previous studies showed that glucose is used to support the metabolic activity of the cartilaginous fish brain, the distribution and expression levels of glucose transporter (GLUT) isoforms remained undetermined. Optic/ultrastructural immunohistochemistry approaches were used to determine the expression of GLUT1 in the glial blood-brain barrier (gBBB). GLUT1 was observed solely in glial cells; it was primarily located in end-feet processes of the gBBB. Western blot analysis showed a protein with a molecular mass of 50 kDa, and partial sequencing confirmed GLUT1 identity. Similar approaches were used to demonstrate increased GLUT1 polarization to both apical and basolateral membranes in choroid plexus epithelial cells. To explore monocarboxylate transporter (MCT) involvement in shark brain metabolism, the expression of MCTs was analyzed. MCT1, 2 and 4 were expressed in endothelial cells; however, only MCT1 and MCT4 were present in glial cells. In neurons, MCT2 was localized at the cell membrane whereas MCT1 was detected within mitochondria. Previous studies demonstrated that hypoxia modified GLUT and MCT expression in mammalian brain cells, which was mediated by the transcription factor, hypoxia inducible factor-1. Similarly, we observed that hypoxia modified MCT1 cellular distribution and MCT4 expression in shark telencephalic area and brain stem, confirming the role of these transporters in hypoxia adaptation. Finally, using three-dimensional ultrastructural microscopy, the interaction between glial end-feet and leaky blood vessels of shark brain was assessed in the present study. These data suggested that the brains of shark may take up glucose from blood using a different mechanism than that used by mammalian brains, which may induce astrocyte-neuron lactate shuttling and metabolic coupling as observed in mammalian brain. Our data suggested that the structural conditions and expression patterns of GLUT1, MCT1, MCT2 and MCT4 in shark brain may establish the molecular foundation of metabolic coupling between glia and neurons

Incidence and Risk Factors Associated with Readmission After Surgical Treatment for Adrenocortical Carcinoma

Background: Adrenocortical carcinoma (ACC) is a rare disease with a poor prognosis. Given the lack of data on readmission after resection of ACC, the objective of the current study was to define the incidence of readmission, as well as identify risk factors associated with readmission among patients with ACC who underwent surgical resection. Methods: Two hundred nine patients who underwent resection of ACC between January 1993 and December 2014 at 1 of 13 major centers in the USA were identified. Demographic and clinicopathological data were collected and analyzed relative to readmission. Results: Median patient age was 52 years, and 62 % of the patients were female. Median tumor size was 12 cm, and the majority of patients had an American Society of Anesthesiologists (ASA) class of 3–4 (n = 85, 56 %). The overall incidence of readmission within 90 days from surgery was 18 % (n = 38). Factors associated with readmission included high ASA class (odds ratio (OR), 4.88 (95 % confidence interval (CI), 1.75–13.61); P = 0.002), metastatic disease on presentation (OR, 2.98 (95 % CI, 1.37–6.46); P = 0.006), EBL (>700 mL: OR, 2.75 (95 % CI, 1.16–6.51); P = 0.02), complication (OR, 1.91 (95 % CI, 1.20–3.05); P = 0.007), and prolonged length of stay (LOS; ≥9 days: OR, 4.12 (95 % CI, 1.88–9.01); P < 0.001). On multivariate logistic regression, a high ASA class (OR, 4.01 (95 % CI, 1.44–11.17); P = 0.008) and metastatic disease on presentation (OR, 3.44 (95 % CI, 1.34–8.84); P = 0.01) remained independently associated with higher odds of readmission. Conclusion: Readmission following surgery for ACC was common as one in five patients experienced a readmission. Patients with a high ASA class and metastatic disease on presentation were over four and three times more likely to be readmitted after surgical treatment for ACC, respectively

Incidence and Risk Factors Associated with Readmission After Surgical Treatment for Adrenocortical Carcinoma

Background: Adrenocortical carcinoma (ACC) is a rare disease with a poor prognosis. Given the lack of data on readmission after resection of ACC, the objective of the current study was to define the incidence of readmission, as well as identify risk factors associated with readmission among patients with ACC who underwent surgical resection. Methods: Two hundred nine patients who underwent resection of ACC between January 1993 and December 2014 at 1 of 13 major centers in the USA were identified. Demographic and clinicopathological data were collected and analyzed relative to readmission. Results: Median patient age was 52 years, and 62 % of the patients were female. Median tumor size was 12 cm, and the majority of patients had an American Society of Anesthesiologists (ASA) class of 3–4 (n = 85, 56 %). The overall incidence of readmission within 90 days from surgery was 18 % (n = 38). Factors associated with readmission included high ASA class (odds ratio (OR), 4.88 (95 % confidence interval (CI), 1.75–13.61); P = 0.002), metastatic disease on presentation (OR, 2.98 (95 % CI, 1.37–6.46); P = 0.006), EBL (>700 mL: OR, 2.75 (95 % CI, 1.16–6.51); P = 0.02), complication (OR, 1.91 (95 % CI, 1.20–3.05); P = 0.007), and prolonged length of stay (LOS; ≥9 days: OR, 4.12 (95 % CI, 1.88–9.01); P < 0.001). On multivariate logistic regression, a high ASA class (OR, 4.01 (95 % CI, 1.44–11.17); P = 0.008) and metastatic disease on presentation (OR, 3.44 (95 % CI, 1.34–8.84); P = 0.01) remained independently associated with higher odds of readmission. Conclusion: Readmission following surgery for ACC was common as one in five patients experienced a readmission. Patients with a high ASA class and metastatic disease on presentation were over four and three times more likely to be readmitted after surgical treatment for ACC, respectively