Association between Bone Mineral Density and LDL Receptor-Related Protein 5 Gene Polymorphisms in Young Korean Men

Recently, It has been reported that the LDL receptor-related protein 5 (LRP5) regulates bone formation, and that mutations of the gene cause osteoporosis-pseudoglioma syndrome or high bone mass phenotypes. However, the mutations cannot explain a genetic trait for osteoporosis in the general population because of their rarity. From 219 Korean men aged 20-34 yr, we looked for six known polymorphisms causing amino acid changes in the LRP5 coding region, and investigated their association with bone mineral density (BMD) at the following anatomical sites: lumbar spine (L2-L4) and the left proximal femur (femoral neck, Ward's triangle, trochanter and shaft). We found that the Q89R polymorphism was significantly associated with BMD at the femoral neck and Ward's triangle (p=0.004 and <0.001, respectively). However, after adjusting for age, weight and height, a statistically significant association only occurred at the Ward's triangle (p=0.043), and a marginal association was observed at the femoral neck (p=0.098). No A400V, V667M, R1036Q and A1525V polymorphisms were found, and no statistically significant association was found between the A1330V polymorphism and BMD at any sites. Although we failed to demonstrate a clear association between the LRP5 polymorphism and peak bone mass in young men, the present study suggests that larger-scale studies on the Q89R polymorphism need to be performed.

Effects of Glucocorticoid on Apoptosis of Human Bone Marrow Osteogenic Stromal Cells / 대한내분비학회지

BACKGROUND: Osteoporosis is one of the most serious side effects of long-term glucocorticoid therapy, but the mechanism of glucocorticoid-induced bone loss remains poorly defined. Glucocorticoid induces decreased bone formation and death of isolated segments of bone (osteonecrosis) suggesting that glucocorticoid excess may affect the birth or death rate of bone cells and thereby reduce their numbers. It has been known that reduction in bone formation is due to reduced proliferation in osteoblast precursor cells and reduced matrix synthesis in mature osteoblast. Here, we present evidence for dexamethasone-induced apoptosis on human bone marrow stromal cells (hBMSC). To understand the mechanism of glucocorticoid-induced osteoporosis, we investigated the effects of glucocorticoid on primary cultured hBMSC. METHEODS: Treatment with dexamethasone at the concentration of 10-9 M for 3~5 days significantly decreased cleavage tetrazolium salt WST-1 level/concentration by mitochondrial dehydrogenase in viable cells. Greater decrease was observed with higher concentration of dexamethasone (10-7 M, and 10-5 M). Apoptosis was measured by annexin V binding/propidium iodide using fluorescence-activated cell sorter (FACS) analysis and nuclear morphology stained with the fluorescence dye, Hoechst 33342. RESULTS: The level/concentration of apoptotic hBMSC (annexin V positive / PI negative) was increased with 10-9 M dexamethasone (1.2% to 5.3%) and further increased with 10-7 M, and 10-5 M concentration (11.7% and 12.5%, respectively). The same result was observed with Hoechst 33342 staining. CONCLUSION: These results indicate that glucocorticoid induces apoptosis on osteoblast precursor cell, hBMSC, and may contribute to decrease bone formation

Lack of Relationship between Vitamin D Receptor Polymorphism and Bone Erosion in Rheumatoid Arthritis

We performed this study to investigate the possible association between vitamin D receptor (VDR) gene polymorphism and the focal bone erosion in rheumatoid arthritis (RA) patients in Korea. One hundred and fifty-seven RA patients were enrolled and two control groups were selected. The focal bone erosion score was assessed by modified Sharp's method. Genotyping of VDR polymorphisms was performed by polymerase chain reaction and restriction fragment length polymorphism analysis using two restriction enzyme Taq I and Bsm I. Notably, the distribution of VDR genotype in Korean population was different from Caucasians. The frequencies of "tt" and "BB" genotypes were very rare both in RA patients and in control groups. The frequency distribution of the Taq I and Bsm I genotype was not different between RA patients (TT, 93.6%; Tt, 6.4%; tt, 0%; BB, 0.6%; Bb, 5.1%; bb, 94.3%) and control groups (TT, 90.8%; Tt, 7.5%; tt, 1.7%; BB, 1.4%; Bb, 8.1%; bb, 90.5%). There was no significant difference in the focal bone erosion score (mean+/-SD) according to the VDR genotypes of RA patients (TT, 0.92+/-1.79; Tt, 0.4+/-0.79; Bb, 0.43+/-0.80; bb, 0.92+/-1.79; p>0.05). In conclusion, these results suggest that VDR gene polymorphisms are not associated with the focal bone erosion in RA patients in Korea.

Basophil histamine releasability in children with atopic asthma / 천식및알레르기

OBJECTIVE: To evaluate the basophil histamine releasability in response to IgE- and non- IgE-mediated stimuli in children with atopic asthma. Met: Basophil histamine releasability was measured in Dermatophagoides farinae (D. farinae)-sensitive atopic asthmatics, D.farinae-sensitive healthy atopics, non-atopic asthmatics, and healthy non-atopics. Basophils were stimulated with D.farinae, goat antihuman IgE antibody, formyl-Met-Leu-Phe(fMLP), and Calcium ionophore A23187. Histamine was measured by automated fluorometric technique. RESULTS: Sponianeous histamine release was higher in atopic asthmatics compared to healthy non-atopics. Histamine release by D.farinae and by anti-IgE antibody was higher in atopic asthmatics compared to the other groups. There was no difference in histamine release by fMLP among all groups. Histamine release by Calcium ionophore was higher in healthy atopics and non-atopic asthmatics compared to healthy non-atopics. The atopics showed correlation between histamine release by D.farinae, by anti-IgE antibody and total serum IgE levels. CONCLUSIONS: Spontaneous and IgE-mediated histamine release were related to the presence of both atopy and asthma, whereas non-IgE mediated histamine release was different depending on the stimuli.

A Case of Limbal Complex Choristoma Containing Cartilarge

Choristomas are defined as benign congenital overgrowth of normal tissues in an abnormal location, which can contain lacrimal gland, muscle, cartilarge, adipose tissue, nerve, epidermal appendage. There are many reports about choristoma but cartilarge containing choristoma is very rare. We experienced a 20-year-old healthy male patient complaining of mass on limbus. The diagnosis was limbal dermoid. After tumor removal, histopathologically it was proved as complex choristoma. It contains not only muscular tissue, adipose tissue, neural tissue but also cartilarge. We report this case because of the rarity of cartilarge containing choristoma.