Impaired osteogenesis of T1DM bone marrow-derived stromal cells and periosteum-derived cells and their differential in-vitro responses to growth factor rescue.

BACKGROUND: Poor bone quality, increased fracture risks, and impaired bone healing are orthopedic comorbidities of type 1 diabetes (T1DM). Standard osteogenic growth factor treatments are inadequate in fully rescuing retarded healing of traumatic T1DM long bone injuries where both periosteal and bone marrow niches are disrupted. We test the hypotheses that osteogenesis of bone marrow-derived stromal cells (BMSCs) and periosteum-derived cells (PDCs), two critical skeletal progenitors in long bone healing, are both impaired in T1DM and that they respond differentially to osteogenic bone morphogenetic proteins (BMPs) and/or insulin-like growth factor-1 (IGF-1) rescue. METHODS: BMSCs and PDCs were isolated from Biobreeding Diabetes Prone/Worcester rats acquiring T1DM and normal Wistar rats. Proliferation, osteogenesis, and adipogenesis of the diabetic progenitors were compared with normal controls. Responses of diabetic progenitors to osteogenesis rescue by rhBMP-2/7 heterodimer (45 or 300 ng/ml) and/or rhIGF-1 (15 or 100 ng/ml) in normal and high glucose cultures were examined by alizarin red staining and qPCR. RESULTS: Diabetic BMSCs and PDCs proliferated slower and underwent poorer osteogenesis than nondiabetic controls, and these impairments were exacerbated in high glucose cultures. Osteogenesis of diabetic PDCs was rescued by rhBMP-2/7 or rhBMP-2/7 + rhIGF-1 in both normal and high glucose cultures in a dose-dependent manner. Diabetic BMSCs, however, only responded to 300 ng/nl rhBMP-2/7 with/without 100 ng/ml rhIGF-1 in normal but not high glucose osteogenic culture. IGF-1 alone was insufficient in rescuing the osteogenesis of either diabetic progenitor. Supplementing rhBMP-2/7 in high glucose osteogenic culture significantly enhanced gene expressions of type 1 collagen (Col 1), osteocalcin (OCN), and glucose transporter 1 (GLUT1) while suppressing that of adipogenic marker peroxisome proliferator-activated receptor gamma (PPARγ) in diabetic PDCs. The same treatment in high glucose culture only resulted in a moderate increase in Col 1, but no significant changes in OCN or GLUT1 expressions in diabetic BMSCs. CONCLUSIONS: This study demonstrates more effective osteogenesis rescue of diabetic PDCs than BMSCs by rhBMP-2/7 with/without rhIGF-1 in a hyperglycemia environment, underscoring the necessity to tailor biochemical therapeutics to specific skeletal progenitor niches. Our data also suggest potential benefits of combining growth factor treatment with blood glucose management to optimize orthopedic therapeutic outcomes for T1DM patients.

IL-17A deficiency promotes periosteal bone formation in a model of inflammatory arthritis.

BACKGROUND: Interleukin-17A (IL-17A) plays a pathogenic role in several rheumatic diseases including spondyloarthritis and, paradoxically, has been described to both promote and protect from bone formation. We therefore examined the effects of IL-17A on osteoblast differentiation in vitro and on periosteal bone formation in an in vivo model of inflammatory arthritis. METHODS: K/BxN serum transfer arthritis was induced in IL-17A-deficient and wild-type mice. Clinical and histologic inflammation was assessed and periosteal bone formation was quantitated. Murine calvarial osteoblasts were differentiated in the continuous presence of IL-17A with or without blockade of secreted frizzled related protein (sFRP)1 and effects on differentiation were determined by qRT-PCR and mineralization assays. The impact of IL-17A on expression of Wnt signaling pathway antagonists was also assessed by qRT-PCR. Finally, regulation of Dickkopf (DKK)1 expression in murine synovial fibroblasts was evaluated after treatment with IL-17A, TNF, or IL-17A plus TNF. RESULTS: IL-17A-deficient mice develop significantly more periosteal bone than wild-type mice at peak inflammation, despite comparable severity of inflammation and bone erosion. IL-17A inhibits calvarial osteoblast differentiation in vitro, inducing mRNA expression of the Wnt antagonist sFRP1 in osteoblasts, and suppressing sFRP3 expression, both potentially contributing to inhibition of osteoblast differentiation. Furthermore, a blocking antibody to sFRP1 reduced the inhibitory effect of IL-17A on differentiation. Although treatment with IL-17A suppresses DKK1 mRNA expression in osteoblasts, IL-17A plus TNF synergistically upregulate DKK1 mRNA expression in synovial fibroblasts. CONCLUSIONS: IL-17A may limit the extent of bone formation at inflamed periosteal sites in spondyloarthritis. IL-17A inhibits calvarial osteoblast differentiation, in part by regulating expression of Wnt signaling pathway components. These results demonstrate that additional studies focusing on the role of IL-17A in bone formation in spondyloarthritis are indicated.

HIF-1α Promotes Glutamine-Mediated Redox Homeostasis and Glycogen-Dependent Bioenergetics to Support Postimplantation Bone Cell Survival.

Cell-based therapy is a promising strategy in regenerative medicine, but the poor survival rate of the implanted cells remains a major challenge and limits clinical translation. We preconditioned periosteal cells to the hypoxic and ischemic environment of the bone defect site by deleting prolyl hydroxylase domain-containing protein 2 (PHD2), resulting in hypoxia-inducible factor 1 alpha (HIF-1α) stabilization. This strategy increased postimplantation cell survival and improved bone regeneration. The enhanced cell viability was angiogenesis independent but relied on combined changes in glutamine and glycogen metabolism. HIF-1α stabilization stimulated glutaminase-mediated glutathione synthesis, maintaining redox homeostasis at baseline and during oxidative or nutrient stress. Simultaneously, HIF-1α signaling increased glycogen storage, preventing an energy deficit during nutrient or oxygen deprivation. Pharmacological inhibition of PHD2 recapitulated the adaptations in glutamine and glycogen metabolism and, consequently, the beneficial effects on cell survival. Thus, targeting cellular metabolism is an appealing strategy for bone regeneration and cell-based therapy in general.

Effects of the hyperbaric oxygen on de novo bone formation during periosteal distraction.

OBJECTIVE: The purpose of this study was to investigate the effect of hyperbaric oxygen (HBO) therapy on de novo bone formation during periosteal distraction (PD). MATERIALS AND METHODS: Periosteal distraction was performed in 24 mature male New Zealand rabbits using a custom-designed device placed on the lateral surface of the mandibular corpus. Twelve rabbits (group H) were given adjunctive HBO treatment, whereas 12 rabbits (group N) were kept in a normal environment (normobaric oxygen). After a 7-day latency period, the same distraction protocol was applied to both groups. However, the rabbits in group H were treated with pure oxygen at 2.4 atm absolute for 25 times. Both groups were further divided into 2 subgroups and killed after consolidation periods of 4 and 8 weeks. Photodensitometric and histologic analyses were performed to evaluate the newly formed bone. RESULTS: There was no significant difference between the 4-week consolidated HBO group and the 8-week consolidated normobaric oxygen subgroup (P = 0.229). Moreover, there was better bone formation in the 8-week HBO group than in the 8-week control group. CONCLUSION: The results of this study indicate that PD with HBO could be used to increase the quality and the quantity of the bone newly formed by PD.

Tratamento cirúrgico da paquidermoperiostose primária - relato de dois casos / Surgical Treatment of Primary Pachydermoperiostosis: Report of Two Cases / Surgical Treatment of Primary Pachydermoperiostosis: Report of Two Cases

A paquidermoperiostose primária é uma doença rara, caracterizada por aposição excessiva do periósteo do crânio, coexistindo com espessamento da epiderme e derme (paquidermia), provocando deformidades grosseiras. Devido à diversidade de estruturas acometidas, há várias opções cirúrgicas e métodos complementares que são utilizados no tratamento das alterações faciais desses pacientes. Esse trabalho apresenta o lifting subperiosteal como uma opção de tratamento estético para a face de pacientes portadores dessa síndrome, através do relato de dois casos operados no Hospital das Clínicas da Universidade Federal de Minas Gerais.

Primary pachydermoperiostosis is a rare disease characterized by excessive skull affixing of the periosteum, coexisting with thickening of the epidermis and dermis (pachydermia), thereby causing gross deformities. Owing to the variety of affected structures, there are several surgical options and complementary methods that are used in the treatment of facial alterations in these patients. This report describes the use of subperiosteal detachment as an aesthetic treatment option for the faces of two patients with primary pachydermoperiostosis, operated at the Hospital das Clínicas of the Federal University of Minas Gerais.

A prospective study on MRI findings and prognostic factors in athletes with MTSS.

In medial tibial stress syndrome (MTSS) bone marrow and periosteal edema of the tibia on the magnetic resonance imaging (MRI) is frequently reported. The relationship between these MRI findings and recovery has not been previously studied. This prospective study describes MRI findings of 52 athletes with MTSS. Baseline characteristics were recorded and recovery was related to these parameters and MRI findings to examine for prognostic factors. Results showed that 43.5% of the symptomatic legs showed bone marrow or periosteal edema. Absence of periosteal and bone marrow edema on MRI was associated with longer recovery (P = 0.033 and P = 0.013). A clinical scoring system for sports activity (SARS score) was significantly higher in the presence of bone marrow edema (P = 0.027). When clinical scoring systems (SARS score and the Lower Extremity Functional Scale) were combined in a model, time to recovery could be predicted substantially (explaining 54% of variance, P = 0.006). In conclusion, in athletes with MTSS, bone marrow or periosteal edema is seen on MRI in 43,5% of the symptomatic legs. Furthermore, periosteal and bone marrow edema on MRI and clinical scoring systems are prognostic factors. Future studies should focus on MRI findings in symptomatic MTSS and compare these with a matched control group.

Blockade of the hedgehog pathway inhibits osteophyte formation in arthritis.

BACKGROUND: Osteophyte formation is a common phenomenon in arthritis. Bone formation by endochondral ossification is considered a key pathophysiological process in the formation of osteophytes. OBJECTIVE: To examine the hypothesis that inhibition of smoothened (Smo), a key component of the hedgehog pathway inhibits osteophyte formation as the hedgehog pathway mediates endochondral ossification. METHODS: Arthritis was induced in 8-week-old C57/BL6 mice by serum transfer (K/BxN model). Mice were then treated by daily administration of either vehicle or LDE223, a specific small molecule inhibitor for Smo, over 2 weeks starting at the onset of disease. Clinical course of arthritis, histological and molecular changes of bone in the affected joints as well as systemic bone changes were assessed. RESULTS: Serum transfer-induced arthritis led to severe osteophyte formation within 2 weeks of onset. Blockade of Smo inhibited hedgehog signalling in vivo and also significantly inhibited osteophyte formation, whereas the clinical and histopathological signs of arthritis were not affected. Also, systemic bone mass did not change. Smo inhibitor particularly blocked the formation of hypertrophic chondrocytes and collagen type X expression. CONCLUSIONS: The data indicate that blockade of hedgehog signalling by targeting Smo specifically inhibits osteophyte formation in arthritis without affecting inflammation and without eliciting bone destruction at the local and systemic level. Blockade of Smo may thus be considered as a strategy to specifically influence the periosteal bone response in arthritis associated with bone apposition.

Effect of ciprofloxacin/dexamethasone versus ciprofloxacin/hydrocortisone on lipopolysaccharide-induced experimental otitis media.

OBJECTIVES: The purpose of this study is to compare the effect of topical ciprofloxacin/dexamethasone versus topical ciprofloxacin/hydrocortisone on the outcome of lipopolysaccharide (LPS)­induced otitis media with effusion in chinchillas. STUDY DESIGN: A randomized experimental animal study. SETTING: Jerry L. Pettis Veteran's Medical Center. SUBJECTS AND METHODS: Otitis media with effusion was induced in 5 groups of chinchillas, 6 per group, by injecting 0.3 mL (1 mg/mL) of Salmonella enteric LPS into the superior bullae of each chinchilla with a venting needle in place. Each group was treated with 0.2 mL of test substance at ­2, 24, 48, and 72 hours relative to the 0-hour LPS induction. Group 1 was treated with vehicle control. Groups 2 to 5 received 0.3% ciprofloxacin with either 0.1% dexamethasone (group 2), 1% dexamethasone (group 3), 0.1% hydrocortisone (group 4), or 1% hydrocortisone (group 5). The outcome of each treatment was measured by the amount of middle ear effusion present and mucosal thickness at 120 hours posttreatment. RESULTS: Ciprofloxacin/dexamethasone 1% significantly (P = .0150) reduced middle ear effusion compared with control. Ciprofloxacin/dexamethasone 1% significantly reduced the mucosal thickness when compared with vehicle control (P = .0005), ciprofloxacin/dexamethasone 0.1% (P = .0240), and ciprofloxacin/hydrocortisone 0.1% (P = 1.00). Results also showed a dose-response effect between the ciprofloxacin/dexamethasone concentrations. CONCLUSIONS: This study demonstrated that treatment with a combination of topical ciprofloxacin and corticosteroid decreased the middle ear effusion when compared with the control group and that ciprofloxacin/dexamethasone suspension reduced the severity of LPS-induced experimental otitis media more than ciprofloxacin/hydrocortisone did.

Biomechanical analysis of combined treatment of high calcium and bisphosphonate in tibia of steroid-treated growing-phase rats.

Childhood systemic diseases are commonly treated with steroids. Consequently, steroid-induced osteoporosis is often observed as a side effect of steroid therapy. However, osteoporosis of tibia resulting from steroid therapy has not been reported yet. Herein we constructed a steroid-induced osteoporosis in tibia of the growing phase rats to examine internal structural changes of the bone and tried to find out the effect of bisphosphonates as a new and early treatment method. Biomechanical analysis was performed using two-dimensional microdensitometry and three-dimensional pQCT method. In addition, the following evaluations were carried out: noninvasive bone strength measurements in steroid-induced osteoporotic rat tibiae; comparing the effectiveness of single high-calcium diet versus combined treatment of high calcium and bisphosphonate for osteoporosis; and quantitative measurement of four elements (Ca, P, Mg, Zn) in bone matrix. Our data suggested that a combined treatment of high calcium and bisphosphonate was an effective new method to improve and treat steroid-induced osteoporosis in childhood.

Alfacalcidol-stimulated focal bone formation on the cancellous surface and increased bone formation on the periosteal surface of the lumbar vertebrae of adult female rats.

PURPOSE: To investigate the skeletal effects of alfacalcidol alone or in combination with exercise in intact adult female rats. METHODS: Seventy-four 8.5-month-old rats were orally administered 0, 0.005, 0.025, 0.05 or 0.1 microg/kg of alfacalcidol for 12 weeks, alone or in combination with exercise. Cancellous bone histomorphometric measurements were performed on the second lumbar vertebra. RESULTS: At 0.05 and 0.1 microg/kg, alfacalcidol caused a significant increase in cancellous bone volume, accompanied by an increase in trabecular architecture. Percent eroded surface, bone resorption and formation were suppressed by alfacalcidol treatment. However, mineral apposition rate was significantly increased, indicating osteoblast activity was increased. A positive balance between bone formation and resorption was observed in the rats treated with the highest dose of alfacalcidol. Alfacalcidol induced a unique bone formation site ("bouton") on the cancellous surface. These boutons connected adjacent trabeculae and increased trabecular thickness. They exhibited both smooth and scalloped cement lines, suggesting that they were formed by minimodeling- and remodeling-based bone formation. Furthermore, alfacalcidol at 0.1 microg/kg increased periosteal bone formation of the lumbar transverse processes. Bipedal stance exercise alone did not have an effect on bone balance and bone turnover. There were no interactions between alfacalcidol and bipedal stance exercise except for a decrease in bone resorption. CONCLUSION: Alfacalcidol exhibited both anti-catabolic and anabolic effects on bone in intact female rats. The effect of combined treatment with alfacalcidol and bipedal stance exercise was no better than that of alfacalcidol alone.

Stress-induced spiculated periosteal reaction appearing as a malignant bone tumor: a case report.

OBJECTIVE: The aim of this study was to describe the appearance of a rare occurrence of a spiculated periosteal reaction caused by stress injury and the subsequent diagnostic assessments. A proposed mechanism for the etiology of stress-induced periosteal reactions in this case is offered. CLINICAL FEATURES: A 54-year-old female had ankle pain for 1 year. Radiographs revealed a spiculated periosteal reaction of the distal fibula. In light of the clinical history of prior breast carcinoma, the possibility of metastatic disease was entertained. INTERVENTION AND OUTCOME: Scintigraphy and magnetic resonance imaging were used in the diagnostic evaluation of this patient. Malignancy was ruled out on the basis of the magnetic resonance imaging findings, and an etiology of a stress reaction was proposed based on the scintigraphic findings. CONCLUSION: Stress-induced spiculated periosteal reactions are a rare occurrence. This case illustrates the role that advanced imaging plays in the assessment of a suspicious periosteal reaction.

The effect of hyperbaric oxygen treatment on bone tissue reactions to c.p. titanium implants placed in free autogenous bone grafts. A histomorphometric study in the rabbit mandible.

This study aimed to investigate the effect of hyperbaric oxygen (HBO) therapy on the tissue reactions to commercially pure (c.p.) titanium implants placed in free autogenous bone graft by a 1-stage procedure. Eighty c.p. titanium implants were placed in the bone grafted from iliac crest to bilateral mandible of 40 Japanese white rabbits without tapping. Twenty rabbits underwent daily a HBO treatment for 60 min under 2.4 ATA during 20 consecutive days and the other untreated 20 rabbits served as controls. The implants with surrounding bone tissue were retrieved 20, 30, 60, 90 and 120 days after surgery, fixated, dehydrated and embedded in resin. About 20 microns thick ground sections were prepared prior to microscopical observations. The bone area and the bone-to-implant contact inside the threads were calculated separately in the grafted bone and in the host bone for each implant. After 30 and up to 120 days, the HBO treated group showed more bone-to-implant contacts in the grafted bone as compared to the non-HBO treated group. In the host bone there were no differences observed between HBO and non-HBO treated groups. This study indicated that HBO treatment was beneficial for the tissue incorporation of c.p. titanium implants when placed immediately in free autogenous bone grafts.

Childhood chondrosarcoma: MR imaging with gadolinium-DTPA.

The radiologic, CT, MR, and histological features of a case of chondrosarcoma of the femur presenting in childhood are reported. This case emphasizes the use of correlative imaging in establishing the diagnosis as well as the value of MR supplemented by Gadolinium-DTPA enhancement in disclosing abundant necrosis within the tumor.

Histomorphometric evaluation of the effects of intermittent 1,25-dihydroxycholecalciferol administration on cortical bone remodeling in adult dogs.

The effects of intermittent low doses (1.25 mug daily, administered intravenously for 6 days and withdrawn for 14 days for 3 complete cycles) of 1,25-dihydroxycholecalciferol (1,25-[OH](2)D(3)) on cortical bone were determined and compared in ribs with steady state and regionally accelerated remodeling in adult intact female dogs. The bone changes were analyzed by dynamic bone histomorphometric methods, using tetracycline and DCAF (2,4 BIS) N, N' di (carboxymethyl) (amino methyl fluorescein) in vivo double labeling of bones before treatment and after 60 days of intermittent 1,25-(OH)(2)D(3) administration. Serum calcium and phosphorus levels increased during 1,25-(OH)(2)D(3) administration. Urinary hydroxyproline excretion increased during the first interval of 1,25-(OH)(2)D(3) administration but was not changed significantly during the last two intervals. In normal cortical bone (11th rib) following the administration of 1,25-(OH)(2)D(3) there was a marked decrease in the activation frequency, bone formation rate, osteoid seam thickness, seam circumference, and mean appositional rate. Although recruitment of new remodeling sites was decreased after 1,25-(OH)(2)D(3), previously existing remodeling units continued to completion. These effects resulted in a preponderance of mature osteons in normal cortical bone. The morphometric changes in cortical bone (9th rib) exposed to both 1,25-(OH)(2)D(3) and periosteal elevation were characterized by a marked increase in both the activation frequency and bone formation rate and associated with a decrease in the osteon formation time. Other morphometric parameters that were increased included radial closure rate, numbers of osteoid seams and resorption cavities, ratio of bone resorbing to forming sites, percentage labeled and circumference of osteoid seams, and total and cortical bone areas. The combined effect of periosteal elevation and 1,25-(OH)(2)D(3) were markedly different from those observed with 1,25-(OH)(2)D(3) alone. These findings suggest that the rapid bone turnover induced by tissue injury will mask or alter the effects of hormones on bone remodeling when studied over a relatively short period of time.

The electrical enhancement of periosteal proliferation in normal and delayed fracture healing.

Normal fracture healing in long bones is a poorly defined process which to a great extent is dependent on periosteal response to injury. When this normally effective mechanism fails, electrical enhancement may prove an effective adjunct and less morbid solution than standard bone grafting procedures for periosteal reactivation.