Low density lipoprotein receptor-related protein 5 gene polymorphisms and osteoporosis in Thai menopausal women.

BACKGROUND: Osteoporosis, characterized by low bone mineral density (BMD) and high bone fracture risk, is prevalent in Thai menopausal women. Genetic factors are known to play a key role in BMD. Low density lipoprotein receptor-related protein 5 (LRP5), a co-receptor in the Wnt/beta-catenin pathway, is involved in many aspects of bone biology. As coding single nucleotide polymorphisms (cSNPs) of LRP5, including A1330V (rs3736228), and Asian-related Q89R (rs41494349) and N740N (rs2306862), are associated with lowered BMD, this study aimed to determine the relationship between these LRP5 polymorphisms and BMD in 277 Thai menopausal women. RESULTS: Only rs3736228 deviated from the Hardy-Weinberg equilibrium of allele frequency (p = 0.022). The median, range and p value for the BMD related to each SNP parameter were compared (Mann-Whitney U test). Significant differences were observed between wild-type and risk alleles for both rs3736228 (total radial, p = 0.011; and radial 33, p = 0.001) and rs2306862 (radial 33: p = 0.015) SNPs, with no significant difference for rs41494349 SNP. Linkage disequilibrium was strong for both rs3736228 and rs2306862 SNPs. Haplotype analysis identified high CC frequency in both normal and osteopenia/osteoporosis groups, with a significant odds ratio for carrying the TT haplotype; however, this was non-significant after adjusting for age. Multivariate binary logistic regression analysis performed for rs3736228 showed that individuals with a body mass index <25 kg/m(2) had an increased risk of osteoporosis for each decade, but the polymorphism had no effect. CONCLUSIONS: This study did not identify LRP5 polymorphisms as a risk factor for osteoporosis in Thai menopausal women. Further studies with larger sample sizes are needed to further clarify the role of LRP5 as a genetic determinant of osteoporosis.

R219K polymorphism of ATP binding cassette transporter A1 related with low HDL in overweight/obese Thai males.

BACKGROUND: ATP binding cassette transporter A1 (ABCA1) plays a role in the initial stage of removing cholesterol from the body via cholesterol efflux. Mutations of this gene cause wide-ranging HDL deficiency, as evident in Tangier disease and familial hypoalphalipoproteinemia. The aim of this study was to elucidate whether the presence of ABCA1 gene polymorphism could be a risk factor for overweight/obesity. METHODS: The presence of R219K and I883M genetic variant was determined by PCR-RFLP analysis in 112 overweight/obese and 117 control subjects of both sexes. Statistical analysis was performed to find an association between polymorphism and lipid data. RESULTS: Overweight/obese men carrying the mutant allele of R219K had lower level of HDL than the control (p = 0.006). However, no positive association was observed using bivariate logistic regression analysis. On the contrary, there was no difference in HDL level among genotypes in I883M polymorphism. Both polymorphisms appeared to be common in Thai ethnic groups. No difference was detected in genotype frequency between the two populations for both polymorphisms. CONCLUSIONS: Although the lower level of HDL in overweight/obese men carrying R219K in comparison to the control suggests the possible involvement of this gene with obesity, further investigations are needed to prove the influence of ABCA1 gene polymorphism on HDL level and to determine whether it could be a genetic determinant of obesity.

Effect of metalloprotease inhibitors on invasion of red blood cell by Plasmodium falciparum.

For successful invasion, the malaria merozoite needs to attach to the red blood cell membrane, undergo reorientation, form a junction of the apical end with the host membrane, and internalize. Malaria proteases have been implicated in the invasion process, but their specific cellular functions remain unclear. To demonstrate the involvement of metalloprotease in the process of Plasmodium falciparum merozoite entry into host red blood cell, schizont-infected red blood cells and parasitophorous vacuolar membrane-enclosed merozoite structures were treated with 1,10-phenanthroline, a metal chelator, resulting in a reduction of invasion with IC50 value of 25 and 29 microM, respectively. Absence of an accumulation of schizont stages after treatment with 1,10-phenanthroline indicated that the inhibitory effect was not due to suppression of merozoite release from red blood cells, but on the invasion step. Although treatment with GM6001, a well-known inhibitor of the mammalian matrix and disintegrin metalloprotease family, was less effective, nevertheless this study points to the importance of metal-requiring protease in the process of invasion of host red blood cell by the malaria parasite.