• Molecules and Cells
• /
• v.38 no.3
• /
• pp.267-272
• /
• 2015

Nacre seashell is a natural osteoinductive biomaterial with strong effects on osteoprogenitors, osteoblasts, and osteoclasts during bone tissue formation and morphogenesis. Although nacre has shown, in one study, to induce bridging of new bone across large non-union bone defects in 8 individual human patients, there have been no succeeding human surgical studies to confirm this outstanding potency. But the molecular mechanisms associated with nacre osteoinduction and the influence on bone marrow-derived mesenchymal stem cells (BMSC's), skeletal stem cells or bone marrow stromal cells remain elusive. In this study we highlight the phenotypic and biochemical effects of Pinctada maxima nacre chips and the global nacre soluble protein matrix (SPM) on primary human bone marrow-derived stromal cells (hBMSCs) in vitro. In static co-culture with nacre chips, the hBMSCs secreted Alkaline phosphatase (ALP) at levels that exceeded bone morphogenetic protein (rhBMP-2) treatment. Concentrated preparation of SPM applied to Stro-1 selected hBMSC's led to rapid ALP secretions, at concentrations exceeding the untreated controls even in osteogenic conditions. Within 21 days the same population of Stro-1 selected hBMSCs proliferated and secreted collagens I-IV, indicating the premature onset of an osteoblast phenotype. The same SPM was found to promote unselected hBMSC differentiation with osteocalcin detected at 7 days, and proliferation increased at 7 days in a dose-dependent manner. In conclusion, nacre particles and nacre SPM induced the early stages of human bone cell differentiation, indicating that they may be promising soluble factors with osteoinductive capacity in primary human bone cell progenitors such as, hBMSC's.

• The Korean Journal of Pharmacology
• /
• v.7 no.1
• /
• pp.53-65
• /
• 1971

It is well known that diabetes mellitus is associated with metabolic derangements, such as hyper-glycemia, ketosis, glycosuria, and also widespread alterations in the blood vessels, kidneys, eyes, peripheral nerves and heart. It is also recognized that healing of skin wound is delayed in diabetics. In bone, according to Aegerter, osteopenia develops in diabetes mellitus and it is chiefly ascribed to overutilization of protein. Shim claims that total blood flow to the entire skeletal system is approximately 4 to 8 percent of resting cardiac output and blood supply to the skeletal system would be decreased on account of secondary arteriosclerotic changes in the diabetics. An adequate blood supply is an essential factor in the healing process of fracture, and disturbed blood flow, either local or systemic, will invariably delay union of the fragments or the fragments from being fused. As the author has encountered several cases of diabetics in whom healing of fracture was delayed or incomplete, this experimental study was undertaken to elucidate the effects of hyperglycemia and diabetes mellitus on the healing process of fracture. In this experiment adult albino rabbits, weighing about 2 kg. were used and divided into 6 groups. The femur of each animal was fractured surgically, and then the healing process of fracture was periodically checked by radiography at an interval of one week for a period of 6 weeks. Thereafter, all the rabbits were killed to obtain tissue preparation of the femur. The experimental groups were as follows; 1) Control group: Six rabbits sustained a surgical fracture to the femur, without being given any other treatment or drug. 2) Alloxan-treated group: For inducing diabetes, alloxan was given intravenously to 17 rabbits in various dose as follows; to 7 of them 40 mg/kg, to 6 rabbits 80 mg/kg and to 4 rabbits 120 mg/kg of body weight, respectively. 3) Insulin-treated group: Protamine-zinc insulin was injected subcutaneously to each of 6 rabbits in a daily dose of 1 unit per kilogram of body weight. 4) Group treated with insulin after alloxan: Four rabbits were given 80 mg of alloxan once and than 1 unit of insulin per kilogram of body weight daily. Another 5 rabbits were injected 1 unit of insulin per kg of body weight daily following administration of alloxan in a dose of 120 mg/kg. 5) Homotransplantation group: Following intravenous injection of alloxan in a dose of 120 mg/kg, 10 rabbits underwent homotransplantation of a short bone segment to the femur. Five of them were subsequently given 1 unit/kg of insulin daily. 6) Sugar-treated group: six rabbits were fed $15{\sim}20$ gm of sugar daily throughout the period of experiment. The results obtained are summarized as follows; 1. Blood sugar level and damage to the pancreatic islet increased proportionately when alloxan was given to the rabbits in various doses. No appreciable change could be observed in the islets when the blood sugar level was altered by either oral administration of sugar or subcutaneous injection of insulin. 2. Comparing with the control group, healing of fracture was delayed in the alloxan-treated group, while callus formation and periosteal reaction were shown to be more prominent in this group and subsequently, the ultimate osseous tissue formed at the fracture site was significantly smaller in amount and less compact. These findings were more marked as the amount of alloxan increased. 3. Administration of insulin prevented the delay in healing process of fracture in the rabbits with alloxan-induced hyperglycemia. In this case, the course and progression of fracture healing were almost similar to those of control group. 4. Union between the host bone and the fragment transplanted from other rabbit of the same species was more delayed in the group treated with alloxan alone than in the group to which insulin was administered after development of alloxan-induced diabetes. In both groups periosteal new bone developed from the ends of the host bone, above and below the transplanted fragment, and directly fused with failure of periosteal callus to bridge the adjacent ends of the host bone and the transplanted fragment. 5. The healing process of fracture was not inhibited by alteration in blood sugar level when the blood sugar was abnormally increased by excessive sugar intake or lowered by administration of insulin alone. The healing of fracture in these groups progressed similarly as in the control group. In brief summary, it appears that the healing process of fracture would be definitely disturbed in diabetic state brought about by damage to the pancreatic islet. As such an inhibition could be overcome with insulin, it seems that insulin plays an important role in healing of fracture, but alteration in blood sugar level alone does not modify healing process of fracture to significant degree.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.5
• /
• pp.385-396
• /
• 2001

The purpose of this experiment was to examine the histological changes and the pattern of expression of proliferating cell nuclear antigen(PCNA) and type I collagen in the elongated bone affected by osteodistraction of the mandibular body in an adult canine model. Seven adult male mongrel dogs weighing over 20kg were used for this experiment. The author excluded 3 animals because they died before the planned time of sacrifice. The custom-made linear extraoral device and 4 bicortical fixation screws 2.3mm in diameter, 50mm in total length, 15mm in screw length were used in each animal. The distal part of the distractor produced a 0.75mm gap between proximal and distal bony segments every $360^{\circ}$ turn of the rotation rod of the device. The mandibular body of the right side from each animal was experimental side and the left side was left intact and served as control. At the experimental side, the mandibular body was osteotomized. After 5-day latency period, the segments were distracted with a rate of 1.1mm/day and a rhythm of two/day for ensuing 7 days. The animals were sacrificed at the 4th. 17th, and 32th day after the end of the distraction. The bony specimens were decalcified, embedded in paraffin, sectioned $5{\mu}m$ thick and stained with Masson trichrome and examined under the light microscope. The immunohistochemical examinations using anti-PCNA antibody and anti-type-I collagen antibody were performed to examine the pattern of the expression of PCNA and type I collagen, respectively. Results : 1. The mean increment of the distance between the proximal and distal screw-holding parts of the distractor was 6.8mm. The average elongation of the mandible in the experimental side was 5.3mm. The loss of elongation was 1.5mm in average. 2. New bone was already observed at the 4th. day after the end of distraction. But, bony union was not completed in the distraction gap at the 32th. day after the end of distraction by radiographic and microscopic examinations. 3. The expression rate of PCNA positive cells in the distraction gap had a tendency of decrease from 35.1-68.8% initially, to 49.1%, and finally to 17.6-27.2%. But at the final period, the tissue of the elongated gap still had the ability of cell proliferation. On the other hand, the expression of PCNA positive cells in the control side were negligible through the experimental period. 4. PCNA positive cells were observed primarily both at the central fibrous zone and at the region of just adjacent to CFZ which initiated new bone formation. 5. The expression pattern of the type I collagen was not zone-specific. They were observed diffusely throughout the elongation gap. 6. The predominant mechanism of new bone formation in the distraction gap was intramembranous. But, some of the regenerated bone was formed by endochondral ossification.