Short-term moderate hypothermia stimulates alkaline phosphatase activity and osteocalcin expression in osteoblasts by upregulating Runx2 and osterix in vitro

Exposure of Normal Human Osteoblast cells (NHOst) to a period of hypothermia may interrupt their cellular functions, lead to changes in bone matrix and disrupt the balance between bone formation and resorption, resulting in bone loss or delayed fracture healing. To investigate this possibility, we exposed NHOst cells to moderate (35 °C) and severe (27 °C) hypothermia for 1, 12, 24 and 72 h. The effects of hypothermia with respect to cell cytoskeleton organization, metabolic activity and the expression of cold shock chaperone proteins, osteoblast transcription factors and functional markers, were examined. Our findings showed that prolonged moderate hypothermia retained the polymerization of the cytoskeletal components. NHOst cell metabolism was affected differently according to hypothermia severity. The osteoblast transcription factors Runx2 and osterix were necessary for the transcription and translation of bone matrix proteins, where alkaline phosphatase (Alp) activity and osteocalcin (OCN) bone protein were over expressed under hypothermic conditions. Consequently, bone mineralization was stimulated after exposure to moderate hypothermia for 1 week, indicating bone function was not impaired. The cold shock chaperone protein Rbm3 was significantly upregulated (p<0.001) during the cellular stress adaption under hypothermic conditions. We suggest that Rbm3 has a dual function: one as a chaperone protein that stabilizes mRNA transcripts and a second one in enhancing the transcription of Alp and Ocn genes. Our studies demonstrated that hypothermia permitted the in vitro maturation of NHOst cells probably through an osterix-dependent pathway. For that reason, we suggest that moderate hypothermia can be clinically applied to counteract heat production at the fracture site that delays fracture healing.

Homozygous familial hypercholesterolemia

We report a rare case of homozygous familial hypercholesterolemia (HoFH), a 22-year-old Malay woman who presented initially with minor soft tissue injury due to a cycling accident. She was then incidentally found to have severe xanthelasma and hypercholesterolemia (serum TC 15.3 mmol/L and LDL-C 13.9 mmol/L). She was referred to the Specialized Lipid Clinic and was diagnosed with familial hypercholesterolemia (FH) based on the Simon Broome (SB) diagnostic criteria. There was a family history of premature coronary heart disease (CHD) in that three siblings had sudden cardiac death, and of consanguineous marriage in that her parents are cousins. DNA screening of LDLR and APOB genes was done by Polymerase Chain Reaction (PCR), followed by Denaturing High Performance Liquid Chromatography (DHPLC). Homozygous mutation C255S in Exon 5 of her LDLR gene was found. There was no mutation was found in Exon 26 and Exon 29 of the APOB gene. This report is to emphasize the importance of identifying patients with FH and cascade screening through established diagnostic criteria and genetic studies in order to ensure early detection and early treatment intervention to minimize the risk of developing CHD and related complications.

Alteration of cell cytoskeleton and functions of cell recovery of normal human osteoblast cells caused by factors associated with real space flight

Experiments involving short-term space flight have shown an adverse effect on the physiology, morphology and functions of cells investigated. The causes for this effect on cells are: microgravity, temperature fluctuations, mechanical stress, hypergravity, nutrient restriction and others. However, the extent to which these adverse effects can be repaired by short-term space flown cells when recultured in conditions of normal gravity remains unclear. Therefore this study aimed to investigate the effect of short-term spaceflight on cytoskeleton distribution and recovery of cell functions of normal human osteoblast cells. The ultrastructure was evaluated using ESEM. Fluorescent staining was done using Hoechst, Mito Tracker CMXRos and Tubulin Tracker Green for cytoskeleton. Gene expression of cell functions was quantified using qPCR. As a result, recovered cells did not show any apoptotic markers when compared with control. Tubulin volume density (p<0.001) was decreased significantly when compared to control, while mitochondria volume density was insignificantly elevated. Gene expression for IL-6 (p<0.05) and sVCAM-1 (p<0.001) was significantly decreased while alkaline phosphatase (p<0.001), osteocalcin and sICAM (p<0.05) were significantly increased in the recovered cells compared to the control ones. The changes in gene and protein expression of collagen 1A, osteonectin, osteoprotegerin and beta-actin, caused by short-term spaceflight, were statistically not significant. These data indicate that short term space flight causes morphological changes in osteoblast cells which are consistent with hypertrophy, reduced cell differentiation and increased release of monocyte attracting proteins. The long-term effect of these changes on bone density and remodeling requires more detailed studies.

Real space flight travel is associated with ultrastructural changes, cytoskeletal disruption and premature senescence of HUVEC

Microgravity, hypergravity, vibration, ionizing radiation and temperature fluctuations are major factors of outer space flight affecting human organs and tissues. There are several reports on the effect of space flight on different human cell types of mesenchymal origin while information regarding changes to vascular endothelial cells is scarce. Ultrastructural and cytophysiological features of macrovascular endothelial cells in outer space flight and their persistence during subsequent culturing were demonstrated in the present investigation. At the end of the space flight, endothelial cells displayed profound changes indicating cytoskeletal lesions and increased cell membrane permeability. Readapted cells of subsequent passages exhibited persisting cytoskeletal changes, decreased metabolism and cell growth indicating cellular senescence.

Serum bone specific alkaline phosphatase and urinary deoxypyridinoline in postmenopausal osteoporosis

The objectives of this study were to: (i) evaluate the diagnostic sensitivity and specificity of the biochemical bone markers: serum total alkaline phosphatase (TALP), bone specific alkaline phosphatase (BSALP) and urinary deoxypyridinoline (Dpyr) in postmenopausal osteoporosis, (ii) compare the bone turnover of postmenopausal osteoporotic patients without and with hormone replacement therapy (HRT) against controls and (iii) identify the correlation between these bone markers and bone mineral density (BMD). We examined 42 postmenopausal women with BMD proven osteoporosis and 35 control subjects. Serum TALP, BSALP and urinary Dpyr were measured. All three biochemical bone markers showed comparable moderate diagnostic sensitivity but Dpyr had the highest diagnostic specificity. There were significantly higher serum TALP, BSALP and urinary Dpyr levels in non-HRT treated patients compared to controls (p<0.005, <0.0001 and <0.005 respectively). There were no significant differences in the levels of all three bone markers between HRT treated patients and control subjects. There was no significant correlation between TALP, BSALP or Dpyr and BMD in both controls and patients. In conclusion, the biochemical bone markers are not useful in diagnosis of postmenopausal osteoporosis but may have a role in monitoring progress and response to treatment. HRT treatment reduces bone turnover of postmenopausal osteoporosis.

Acute effects of acarbose on post-prandial glucose and triglycerides in type 2 diabetics following intake of different Malaysian foods

Acarbose inhibits intestinal alpha-glucosidases resulting in diminished and delayed postprandial hyperglycaemia (PPH). Studies on effects of acarbose on postprandial lipaemia (PPL) have been inconclusive. Little is known about the effects of acarbose on PPH and PPL following intake of a polysaccharide diet. We studied 30 type 2 diabetic patients on dietary and/or oral hypoglycaemic agent(s). Thirty patients were recruited for food A (nasi lemak), 28 for food B (mee goreng) and 28 for food C (roti telur), which represent the typical diets of the three main races in Malaysia. Serial blood samples were taken at 15 min before and up to 240 min after each food intake, without acarbose. Subsequently, three doses of 50 mg acarbose were given orally and the same procedure was repeated the following day. There were significantly lower mean increments in plasma glucose levels after compared to before acarbose treatment 30, 45 and 60 min for food A and at 30, 45, 60, 120, 180 and 240 min for food C, but no significant difference was noted for food B. There was a significantly lower mean fasting glucose level after compared with before acarbose treatment following intake of food A and C but not food B. Short-term treatment with acarbose caused significant diminished and delayed PPH response with food A and C but not with food B. Acarbose was more effective in reducing PPH response in polysaccharide foods with a higher and earlier postprandial glucose peak than in those with a lower and lagged peak. There were no significant differences in the mean fasting or postprandial triglyceride levels before and after acarbose treatment, following intake of all three foods for up to 4 hours. Depending on the food absorption pattern, overnight low dose treatment with acarbose leads to diminished fasting and peak plasma glucose levels, and delayed PPH but insignificant reduction in postprandial lipaemia in poorly controlled type 2 diabetics following intake of racially different Malaysian food.