Autologous transplantation of adipose-derived stem cells enhances skin graft survival and wound healing in diabetic rats.

BACKGROUND: Diabetes can lead to impaired wound healing and skin grafts used surgically for diabetic wounds are often complicated with necrosis, although different therapies have been proposed. Adipose-derived stem cells (ASCs) participate in tissue repair processes and may have a role during impaired wound healing. In this study, autologous transplantation of ASCs was used to determine if it increases angiogenesis and skin graft survival and enhances wound healing in diabetic rats. METHODS: Adipose-derived stem cells were successfully isolated and cultured. A full-thickness skin graft model was used to determine the effects of locally administered ASCs in 10 rats rendered diabetic (group 1), whereas 10 others served as controls (group 2). Histological examination of skin grafts followed after 1 week. Additionally, immunohistochemical staining intensity of vascular endothelial growth factor (VEGF) and transforming growth factor ß3 (TGF-ß3) was assessed in all grafts. RESULTS: The gross and histological results showed significantly increased survival, angiogenesis, and epithelialization. Mean area of graft necrosis was significantly less in group 1 than in group 2 (7.49% vs 39.67%, P < 0.001). Statistically significant increase of capillary density, collagen intensity, VEGF, and TGF-ß3 expression was noted in group 1 compared with group 2. CONCLUSIONS: These findings suggest that autologous ASC transplantation can enhance skin graft survival in diabetic rats through differentiation, vasculogenesis, and secretion of growth factors such as VEGF and TGF-ß3. This might represent a novel therapeutic approach in skin graft surgery for diabetic wounds.

Effect of rheumatoid arthritis on volumetric bone mineral density and bone geometry, assessed by peripheral quantitative computed tomography in postmenopausal women treated with bisphosphonates.

OBJECTIVE: To investigate the effect of rheumatoid arthritis (RA) on volumetric bone mineral density (vBMD) and bone geometry in postmenopausal women treated with bisphosphonates. METHODS: Fifty-three postmenopausal women with RA and 87 control subjects, comparable in terms of age, body mass index, and years since menopause, underwent peripheral quantitative computed tomography (pQCT) of the nondominant tibia. RESULTS: At 4% (trabecular site), trabecular bone mineral content (BMC) and vBMD (p < 0.001) were lower in the RA group, while trabecular area was comparable. At 38% (cortical site), cortical BMC (p < 0.01), area (p < 0.05), and thickness (p < 0.001) were lower in the RA group, whereas vBMD was comparable. Endosteal circumference was higher (p < 0.05), whereas periosteal circumference was comparable, indicating cancellization of cortical bone. In the RA group, muscle area was lower (p < 0.001), while at 14% polar stress strength index was significantly lower (p < 0.01) in patients with RA, indicating impairment of bone mechanical properties. CONCLUSION: RA is associated with negative effects on both cortical and cancellous bone in postmenopausal women treated with bisphosphonates. Cortical geometric properties are also adversely affected mainly by increased endosteal circumference, whereas trabecular geometric properties are generally preserved.

Osteogenic activity of ß-tricalcium phosphate in a hydroxyl sulphate matrix and demineralized bone matrix: a histological study in rabbit mandible.

Currently, in oral and maxillofacial surgery, there is a clinical need for efficient bone grafting materials, and various efforts are being made to improve materials used as bone substitutes to facilitate faster and denser bone regeneration. The purpose of this study was to evaluate in vivo the osteogenic potential of synthetic ß-tricalcium phosphate in a hydroxyl sulphate matrix (ß-TCP/HS) and human demineralized bone matrix (DBM) putty. Sixteen New Zealand White rabbits were used. In each animal, two bone defects (8 mm length × 3 mm width × 3 mm depth) were created in the left and right regions of the mandible, respectively. The defect on one side, chosen randomly, was filled with ß-TCP/HS (group A) or DBM putty (group B), while the defect on the opposite side was left unfilled in order to serve as a control site. Two animals in each group were sacrificed at the end of the 1st, 3rd, 5th and 6th week after surgery, respectively, and the osteotomy sites were processed for histological evaluation. Our findings confirmed that ß-TCP/HS and human DBM putty possess osteogenic activity and can support new bone formation, although at a slower rate than the spontaneous healing response, in rabbit mandibular osseous defects.

Quantitative ultrasound of the calcaneus in greek women: normative data are different from the manufacturer's normal range.

Quantitative ultrasound (QUS) is considered a useful method in evaluating bone status. The aim of the present study was to establish the reference data for the QUS measurements of the calcaneus in a Greek population. We measured a QUS parameter, stiffness index (SI), at the right calcaneus in 1500 women using the Achilles express Ultrasonometer (GE Lunar, Madison, WI). Participants were divided into 7 groups according to their age with a 10-yr span in each group. A progressive decline was found in the SI values after the age of 39 yr in the current study. When the SI values were compared between the age groups, high statistically significant differences were obvious, especially between 20-29 and 50- to 59-yr age groups and 60-69 and 70- to 79-yr age groups (p < 0.0005). Additionally, in the Greek normal range (GNR), the SI values of those aged 60-69 and 70-79 yr were significantly higher (81.84+/-16.14 and 77.45+/-17.65, respectively) than those in the manufacturer's normal range (MNR; 75.84+/-16.14 and 69.10+/-17.65, p < 0.005, respectively). Using the manufacturer's values, significantly fewer women were classified as normal (48% vs 67.3%), although those with T-score < or =-2.5 were more (15.7%) compared with our Greek value (1.5%), and classification of subjects into risk-of-fracture categories was significantly different (kappa: 0.459, 66.2%, p < 0.0005). Multiple regression analysis showed that weight was the most significant predictor for SI in the age groups 30-39 (beta = 0.280, p < 0.05), 40-49, 60-69, and 70-79 yr (beta = 0.185, p < 0.005; beta = 0.329, p < 0.0005; beta = 0.494, p<0.0005, respectively). Using conventional categories of risk, we report a different classification of our subjects from those proposed by the manufacturer, supporting the concept that data specific to the Greek population are necessary.

Effect of sibutramine on regional fat pads and leptin levels in rats fed with three isocaloric diets.

AIM: The aim of the study was to investigate: a) the differential effect of the three main macronutrients on food intake, fat depots and serum leptin levels and b) the impact of sibutramine on the above parameters in rats fed ad libitum with three isocaloric diets. METHODS: Three groups of male Wistar rats (n = 63) were fed with a high fat diet (HFD), a high carbohydrate diet (HCD) or a high protein diet (HPD) for 13 weeks. In the last three weeks, each group was divided into three subgroups and received sibutramine (S) either at 5 mg/kg or 10 mg/kg, or vehicle. Food intake was measured daily during the last week of the experiment; perirenal and epididymal fat and fat/lean ratio were calculated and serum leptin was assayed. RESULTS: HFD-fed rats demonstrated elevated food intake and higher regional fat depots. S at 10 mg/kg decreased food intake in the HFD and epididymal fat in the HCD group. S also reduced perirenal fat in the HCD and HPD groups. Leptin levels were higher in rats fed with either the HFD or the HPD compared to those fed with the HCD. Moreover, S at 10 mg/kg decreased serum leptin levels in the HPD group. CONCLUSIONS: Results suggest a preferential effect of S on perirenal visceral fat and support the view that body fat loss is greater when its administration is accompanied by a HCD diet. No effect of S on leptin levels was found, besides that expected as a result of the decrease in body fat.

Local treatment of experimental Pseudomonas aeruginosa osteomyelitis with a biodegradable dilactide polymer releasing ciprofloxacin.

A biodegradable system of poly-D,L-dilactide releasing ciprofloxacin was assessed in a Pseudomonas aeruginosa osteomyelitis model after inoculation of the test pathogen into the left tibia of 76 New Zealand White rabbits; 31 were controls (group A), and 45 were implanted with the polymer at the infection site (group B). The rabbits were killed on a weekly basis, and cancellous bone was harvested for histopathology and for estimation of bacterial growth and the concentrations of ciprofloxacin. Tibial X ray was performed immediately before the animals were killed. The total number of fistulas with purulent discharge that developed after inoculation of the pathogen was counted, and fistulas with purulent discharge were found in 16 animals in group A (51.6%) and 3 animals in group B (6.7%) (P < 0.0001). The animals in group A had a profound loss of body weight compared to the animals in group B. The main radiological finding was the presence of sequestra in 25 animals (80.6%) in group A and 6 animals in group B (13.3%) (P < 0.0001). The bacterial load in group B was significantly reduced compared to that in group A, possibly due to the prolonged local antibiotic release at concentrations exceeding even 80 times the MIC for the test pathogen. The histology of animals killed after week 49 revealed a mild inflammatory reaction accompanied by diffuse fibrosis and new bone formation in group A animals and the presence of small polymer particles in group B animals. It is concluded that the system described achieved eradication of the pathogen, accompanied by clinical and radiologically confirmed benefits, so this treatment may be a candidate for the management of difficult orthopedic infections.

Rat epigastric flap survival and VEGF expression after local copper application.

BACKGROUND: Copper has been used in wound healing since ancient times, and copper insufficiency seems to impair wound healing. Much less is known about the local effects of copper application on wound healing. METHODS: The authors studied 30 male Sprague-Dawley rats weighing between 250 and 350 g for 5 days. Full-thickness random skin flaps, measuring 1.5 x 7.5 cm, were elevated on the epigastric region. The rats were randomized into two groups according to the local treatment that was used. In group 1 (20 animals), 1 ml of copper ointment was applied on the flap bed after flap suturing. In group 2 (10 animals), 1 ml of placebo ointment (petroleum jelly) was used. Intraperitoneal injection of 30 mg/kg body weight of Hypoxyprobe-1 was performed in each rat on the fourth postoperative day and all animals were killed 3 hours later. Histologic examination of the distal end of the flaps was used for detection of hypoxic tissue changes. Expression, density, and extent of vascular endothelial growth factor activity was detected with the aid of immunocytochemistry. RESULTS: All rats survived throughout the study period. This experimental study showed that local application of copper at the random flap bed may promote wound-related angiogenesis by inducing vascular endothelial growth factor expression. The authors demonstrated statistically significant flap survival after local copper application at the flap bed. CONCLUSION: The marked benefits of copper application in flap survival in this experimental model may guarantee its clinical application in flaps with questionable viability.

Colistin offers prolonged survival in experimental infection by multidrug-resistant Acinetobacter baumannii: the significance of co-administration of rifampicin.

The effect of colistin on bacterial eradication and survival was tested in experimental infection by multidrug-resistant Acinetobacter baumannii. The thigh infection model was applied in 86 neutropenic Wistar rats. Six rats were used for the induction of neutropenia and for the selection of the dose regimen of colistin; the remainder was equally divided into four groups: A, controls; B, rifampicin; C, colistin; and D, both agents. Therapy was administered 5 h after bacterial challenge; 5mg/kg of rifampicin was administered intravenously and 3mg/kg of colistin intramuscularly. Survival was recorded in 10 animals of each group. The remaining 10 rats per group were killed 4h after therapy; blood and tissue samples were sampled. Median survival of animals of groups A, B, C and D was 2.00, 2.50, 4.00 and 4.00 days, respectively (P=0.0048 between A and C and P=0.0012 between A and D. Mortality rates after 6 days of follow-up were 100, 100, 100 and 70%, respectively (P=0.018 between groups). Statistically significant decreases of bacteria were found in blood, liver, lung and spleen of group B compared with A; in lung of group C compared with A; and in blood and liver of group D compared with A. Colistin was effective in prolonging survival in an experimental thigh infection by multidrug-resistant A. baumannii in neutropenic rats. Its activity was enhanced after co-administration with rifampicin. These results mandate the application of colistin in the event of infections by multidrug-resistant pathogens and the need for its co-administration with rifampicin.

The infectivity of sarcoid clinical material and its bacterial content inoculated in CBA mice.

BACKGROUND: Sarcoidosis is a multisystemic disorder that is currently viewed as the consequence of chronic immunological response associating genetic susceptibility and specific environmental or transmissible agents. Relevant evidence, although conflicting, justifies a concern about the involvement of specific pathogens to disease causation. In this study we assessed the infectivity of sarcoid clinical material, and of the pathogens found in it, to normal CBA mice used as a model of an immuno-competent host. MATERIALS AND METHODS: One hundred and eleven mice were inoculated into their footpads with fresh, filtered, and autoclaved, sputum and bronchoalveolar lavage homogenates, collected from patients with sarcoidosis, and with the mycobacterial and propionibacterial pathogens isolated from this material. RESULTS: The total number of positive reactors of the animals that received raw clinical material and the pathogens it contained was statistically significant compared to those of the control groups. However, the number of affected mice per group was in most cases less than 50% and inflammation was almost always mild and local. CONCLUSION: Based on the evidence provided by inoculation of normal CBA mice, some of the material under study, although of mild potency, can be infectious to an immuno-competent host.

Ex vivo synergy of arachidonate-enriched serum with ceftazidime and amikacin on multidrug-resistant Pseudomonas aeruginosa.

Three multidrug-resistant strains of Pseudomonas aeruginosa were incubated ex vivo with sera sampled after a 10 min intravenous infusion of 25 mg/kg of arachidonic acid (AA) in 10 rabbits in the presence of ceftazidime and amikacin. Lipid peroxidation was assessed during bacterial growth. A statistically significant decrease in bacterial cells was found by the interaction of antimicrobials and serum sampled in the middle of infusion and 15 and 30 min after infusion of AA and was accompanied by elevated levels of malonodialdehyde. This effect of AA is probably attributed to lipid peroxidation and raises the possibility of its application in experimental infections.

Role of suprahyoid musculature on mandibular morphology and growth orientation in rats.

This study was undertaken in rats to study the influence of the suprahyoid muscles on mandibular growth, morphology, and orientation. The aim was to investigate the effect of bilateral suprahyoid muscle myectomy on the skeletal growth and orientation of the mandible and on its orientation in rats. Forty-eight 4-week-old rats were divided into 2 experimental and 2 control groups as follows: A, 12 animals in which bilateral excision of the anterior digastric muscle was performed; B, 12 animals in which bilateral excision of the anterior digastric, transverse mandibular, and mylohyoid muscles was performed; C, 12 animals that were sham-operated bilaterally without any muscular excision; D, 12 control animals not subjected to any operation. The experimental period was 30 days. Lateral and dorsoventral radiographs were taken on days 1 and 30, after muscular excision. Cephalometric analysis was performed for each animal according to a method and procedure established in our laboratory and described earlier. The findings support the occurrence of decreased mandibular growth in the group in which bilateral digastric, transverse mandibular, and mylohyoid excision was performed as compared with controls. In addition, the mandible in the bilateral digastric excision group exhibited a more upward orientation. It was thus proven that the absence of the suprahyoid musculature does affect both skeletal growth and orientation of the mandible.