The effect of sphingosine-1-phosphate on bone metabolism in humans depends on its plasma/bone marrow gradient.

BACKGROUND: Although recent studies provide clinical evidence that sphingosine-1-phosphate (S1P) may primarily affect bone resorption in humans, rather than bone formation or the osteoclast-osteoblast coupling phenomenon, those studies could not determine which bone resorption mechanism is more important, i.e., chemorepulsion of osteoclast precursors via the blood to bone marrow S1P gradient or receptor activator of NF-κB ligand (RANKL) elevation in osteoblasts via local S1P. AIM: To investigate how S1P mainly contributes to increased bone resorption in humans, we performed this case-control study at a clinical unit in Korea. METHODS: Blood and bone marrow samples were contemporaneously collected from 70 patients who underwent hip surgery due to either osteoporotic hip fracture (HF) (n = 10) or other causes such as osteoarthritis (n = 60). RESULTS: After adjusting for sex, age, BMI, smoking, alcohol, previous fracture, diabetes, and stroke, subjects with osteoporotic HF demonstrated a 3.2-fold higher plasma/bone marrow S1P ratio than those without HF, whereas plasma and bone marrow S1P levels were not significantly different between these groups. Consistently, the risk of osteoporotic HF increased 1.38-fold per increment in the plasma/bone marrow S1P ratio in a multivariate adjustment model. However, the odds ratios for prevalent HF according to the increment in the plasma and bone marrow S1P level were not statistically significant. CONCLUSION: Our current results using simultaneously collected blood and bone marrow samples suggest that the detrimental effects of S1P on bone metabolism in humans may depend on the S1P gradient between the peripheral blood and bone marrow cavity.

The effects of different exercise intensity on myokine and angiogenesis factors.

AIM: Myokines and angiogenesis factors, studies on trainings according to the difference of exercise intensity are not sufficient, and it has not been elucidated. Particularly, studies on the effect of resistance exercise according to the intensity of resistance exercise on blood myokines and angiogenesis may be essential in the metabolic process of angiogenesis and the formation of muscle. METHODS: The subjects of our studies were healthy male college students (N.=30) randomly assigned to the high intensity exercise group (N.=10), the moderate intensity exercise group (N.=10), and the control group (N.=10). The study was performed after obtaining a consent in advance, and the approval from the Institutional Review Board of Dong-A University Hospital. In the body composition test, height, weight, BMI (body mass index), %fat, and LBM (lean body mass) were measured by electric impedance. In blood analysis, myokines (interleukin (IL)-6, IL-8, IL-15) and angiogenesis factors (vascular endothelial growth factor (VEGF), angiopoietin (Ang)1, follistatin (FLRG)) were analyzed by ELISA methods. RESULTS: The results show %body fat and LBM of the three groups were significantly different (P<0.05). IL-6 and IL-8 of the three groups were significantly different (P<0.05). Particularly, IL-8 of RE60 (60% of 1RM) was shown to be significantly higher than other groups (P<0.05). IL-15 also showed significant differences with time (P<0.05). In addition, VEGF and Ang 1 showed significant differences with time (P<0.05), nonetheless, FLRG did not showed statistical differences. CONCLUSION: Many of muscle contraction through 8 weeks resistance exercise exerted positive effects on the concentration of blood myokines as well as angiogenesis. Particularly, in regard to blood myokines, moderate intensity exercise were more effective than high intensity exercise, which is considered to be due to that continuous muscle contraction of moderate intensity exercises exerted more positive effects on the elevation of the concentration of myokines than less muscle contraction of high intensity exercise.

Antioxidant enzyme activities and DNA damage in children with type 1 diabetes mellitus after 12 weeks of exercise.

OBJECTIVE: The objectives of this study are to assess the effects of a low-intensity exercise training which is not risky for children with type 1 diabetes mellitus (T1DM) on the antioxidant enzyme activities and oxidative stresses compared with healthy controls. PATIENTS AND METHODS: We studied 10 boys with T1DM (11.21 +/- 0.97 age) and 10 age-matched healthy controls (11.90 +/- 1.85 age) during the 12 weeks of moderate intensity aerobic exercise. Measurements included peak oxygen uptake, body composition, blood lipid profiles, glycated haemoglobin (HbA1c), oxidized low density lipoprotein (ox-LDL), 8-hydroxy-2'-deoxyguanosine, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. RESULTS: In T1DM patients, the baseline diastolic blood pressure and HbA1c were higher than that in controls (p < 0.05), while the GPx level was lower. The training-induced DNA damage peak was higher in T1DM patients than in controls (p < 0.05), and exercise improved both SOD and GPx levels. CONCLUSION: Although our exercise programme increase antioxidant enzyme activities, the results of the study demonstrate that low-intensity aerobic exercise training programme performed over 12 weeks may accelerate adverse effects of antioxidant defence capacity in children with T1DM. Therefore, the future studies should be performed to clarify much more the relationship to exercise and antioxidant capacity in children with T1DM.

Detection of pseudorabies viral DNA in tonsillar epithelial cells of latently infected pigs.

The Rice strain of pseudorabies virus (PRV) was intranasally instilled in pigs that were seronegative to PRV. Cells were scraped or brushed from tonsillar surfaces biweekly until pigs were euthanatized at either 10 or 16 weeks after infection. The DNA extracted from tonsillar cells or parenchyma were subjected to polymerase chain reaction analysis, using either a single set of oligonucleotide primers or nested primers from the PRV gII glycoprotein gene. Pigs became seropositive to PRV by 3 weeks after infection. The virus was isolated from the trigeminal ganglia and tonsils of pigs that were euthanatized or died 1 to 2 weeks after infection, but not from pigs that were euthanatized 10 or 16 weeks after infection. The PRV gene products were consistently detected in trigeminal ganglia and tonsils of all pigs at 1, 10, and 16 weeks after infection, and sporadically in the nasal mucosa, lymph nodes, and lungs of pigs that were euthanatized or died during the first 2 weeks after infection. Cells collected biweekly from tonsillar surfaces were mostly nucleated, squamous epithelial cells with fewer lymphocytes and neutrophils. Polymerase chain reaction analysis of DNA extracted from these cells revealed PRV DNA in a large proportion of the samples when sufficient cells were collected to provide 1 microgram of extracted DNA for use in the reaction mixtures. A second group of pigs had PRV strain 4892 intranasally instilled. The virus was isolated from tonsillar swab specimens until 3 weeks after infection. Tonsillar brushing specimens were collected biweekly until 14 weeks after infection.(ABSTRACT TRUNCATED AT 250 WORDS)