Genome-wide screening of m6A profiling of cutaneous wound healing in diabetic mice.

OBJECTIVE: Impaired wound healing in diabetes mellitus (DM) is a major health burden on patients, their families, and society. The present study aimed to systematically profile the m6A modification landscape in cutaneous wounds in a diabetic mouse model. APPROACH: Diabetes was induced in mice through a single intraperitoneal injection of streptozotocin (STZ); a single intraperitoneal injection of PBS was made in control mice for comparisons. Both groups then received an 8-mm diameter, full-thickness dorsal body wound with a biopsy punch. Five days after wound surgery, western blot analysis of harvested wound tissues from both groups was used to assess the expression of m6A-related enzymes. Genome-wide profiling of m6A-tagged transcripts was performed through MeRIP-seq and RNA-seq. RESULTS: ALKBH5, an m6A eraser, was significantly upregulated, while METTL3, METTL14, and WTAP, m6A writers, were markedly downregulated in the diabetic wounds. Additionally, a total of 1335 m6A peaks were differentially expressed in MeRIP-seq and RNA-seq analyses, with 558 upregulated and 777 downregulated peaks. Finally, there was hypomethylated and hypermethylated differentiation at the gene and transcript levels. INNOVATION: The present study was the first to reveal the m6A landscape in diabetic wounds in an animal model. CONCLUSION: This study, by deeply analyzing the role of m6A modifications in diabetic wound healing, provides new insights and understanding into the molecular mechanisms of diabetic wound healing. Future research could further explore how m6A modifications regulate the wound healing process, thereby offering new potential targets for the treatment of diabetic wounds.

Staphylococcus aureus enhances osteoclast differentiation and bone resorption by stimulating the NLRP3 inflammasome pathway.

BACKGROUND: Osteomyelitis is one of the most challenging infectious diseases and is mainly caused by Staphylococcus aureus (S. aureus). In this study, we analyzed the effect of S. aureus on osteoclast differentiation and its possible molecular mechanism. METHODS: We cultured RAW 264.7 cells with live S. aureus for 5 days. We assessed cell viability and the formation of resorption pits. We tested the NLRP3 inflammasome signaling pathways and measured the mRNA expression levels of osteoclastspecific genes, including TRAP, MMP9, cathepsin K, calcitonin receptor and ATP6V0d2. Furthermore, we analyzed the protein expression levels of the protein in the NF-κB and p38 MAPK signaling pathways to clarify the signaling pathways by which S. aureus promotes osteoclast differentiation. RESULTS: Staphylococcus aureus induced NLRP3 inflammasome activation. S. aureus promoted bone resorption and enhanced the expression of osteoclastspecific genes, such as TRAP, MMP9, cathepsin K, calcitonin receptor and ATP6V0d2. MCC950 was used to inhibit NLRP3 inflammasome activity. Osteoclast differentiation and the expression of osteoclastspecific genes induced by S. aureus were inhibited by MCC950 pretreatment. The degradation of IκBα and phosphorylation of P65 were increased under the induction of S. aureus, but proteins in the p38 MAPK signaling pathway did not change significantly. CONCLUSION: Staphylococcus aureus induces osteoclast differentiation and promotes bone resorption in vitro, and the NLRP3 inflammasome signaling pathway plays a significant role in this process. S. aureus-induced NLRP3 inflammasome activation was mainly dependent on the NF-κB signaling pathway during osteoclastogenesis.

Application of antibiotic bone cement in the treatment of infected diabetic foot ulcers in type 2 diabetes.

BACKGROUND: In this study, we try to investigate the effect of antibiotic bone cement in patients with infected diabetic foot ulcer (DFU). METHODS: This is a retrospective study, including fifty-two patients with infected DFU who had undergone treated between June 2019 and May 2021. Patients were divided into Polymethylmethacrylate (PMMA) group and control group. 22 patients in PMMA group received antibiotic bone cement and regular wound debridement, and 30 patients in control group received regular wound debridement. Clinical outcomes include the rate of wound healing, duration of healing, duration of wound preparation, rate of amputation, and frequency of debridement procedures. RESULTS: In PMMA group, twenty-two patients (100%) had complete wound healing. In control group, twenty-eight patients (93.3%) had wound healing. Compared with control group, PMMA group had fewer frequencies of debridement procedures and shorter duration of wound healing (35.32 ± 3.77 days vs 44.37 ± 7.44 days, P < 0.001). PMMA group had five minor amputation, while control group had eight minor amputation and two major amputation. Regarding the rate of limb salvage, there was no limb lose in PMMA group and two limb losses in control group. CONCLUSION: The application of antibiotic bone cement is an effective solution for infected DFU treatment. It can effectively decreased the frequency of debridement procedures and shorten the healing duration in patients with infected DFU.

Corrigendum: Application of the distally based sural neurocutaneous flaps in the management of foot and ankle defects in patients with diabetic foot.

[This corrects the article DOI: 10.3389/fendo.2022.1009714.].

Application of the distally based sural neurocutaneous flaps in the management of foot and ankle defects in patients with diabetic foot.

Background: We report our experience on the use of a distally based sural flap for soft tissue reconstruction of foot and ankle defects in patients with diabetic foot. Methods: The actual study is a retrospective, open, non-controlled, and clinical study of 25 patients treated with diabetic foot on whom reconstruction with distally based sural neurocutaneous flaps was performed from May 2019 to December 2021. Results: The mean age was 64.9 years, and there were 15 male and 10 female patients. The mean follow-up was 9.8 months, which ranged from 6 to 12 months. The size of the flaps ranged from 6 × 5 to 15 × 9 cm2. Twenty-two of the 25 flaps survived intact with sufficient blood supply. Two cases had a small superficial necrosis, which was resolved after a change of daily dressing and was heeled eventually. In one case, partial necrosis was observed that was managed with minor revision and the use of split-thickness skin graft. Conclusions: The distally based sural flap is considered to be useful for reconstruction of foot and ankle defects in patients with diabetic foot.

IL-1ß Impaired Diabetic Wound Healing by Regulating MMP-2 and MMP-9 through the p38 Pathway.

Diabetes mellitus is one of the most prominent metabolic disorders in the world, and insulin resistance in diabetic patients leads to several complications including increased inflammation and delayed wound healing. Fibroblast migration and reepithelialization play a significant role in wound healing. In this study, we explored the effects of IL-1ß signaling on proliferation and migration of human fibroblasts from diabetic wound tissues. We observed elevated levels of IL-1ß in samples from diabetic patients when compared to normal wound tissues. At high concentrations, IL-1ß inhibited cell proliferation and migration in ex vivo fibroblast cultures. Moreover, expression of matrix metalloproteinases (MMPs) was upregulated, and tissue inhibitor of metalloproteinases (TIMPs) was downregulated in diabetic wound tissues and cells. These effects were regulated by levels of IL-1ß. Furthermore, IL-1ß induced p38 phosphorylation thereby activating the p38 MAPK pathway that in turn regulated the expression of MMPs and TIMPs. Together, our study identifies a novel mechanism behind delayed wound closure in diabetes mellitus that involves IL-1ß-dependent regulation of cell proliferation and migration.

Association Between Serum 25-OH-Vitamin D and Diabetic Foot Ulcer in Patients With Type 2 Diabetes.

Background: Vitamin D deficiency has been associated with an increased risk in several diabetic complications. We aimed to evaluate the association between vitamin D and diabetic foot ulcer (DFU) in patients with type 2 diabetes. Methods: Fifty one patients were included in the study and divided into two groups for study of vitamin D, cholesterol, and triglycerides in blood serum on DFU. The association between vitamin D and DFU was measured by binary logistic regression analysis. The cut point of vitamin D for DFU was assessed by the receiver operating characteristic curve. Results: Levels of 25-OH-vitamin D were lower in patients with DFU than in DM group (P < 0.0001). The AUC of 25-OH-vitamin D was 0.8254 and had an optimal cut point value (13.68 ng/ml) for the identification of DFU, with a sensitivity of 90% and a specificity of 66.67% in all patients. Multivariate logistic regression analysis indicated that the significant risk factors included 25-OH-vitamin D level (P = 0.001, OR = 0.618) and HDL-C level (P = 0.038, OR = 0.012). Conclusion: Low serum 25-OH-vitamin D level was associated with DFU. This indication was more specific than cholesterol and triglycerides levels.

Treatment of Diabetic Foot with Autologous Stem Cells: A Meta-Analysis of Randomized Studies.

BACKGROUND: This meta-analysis was to evaluate the efficacy of autologous stem cell administration for the treatment of diabetic foot. METHODS: The electronic databases included PubMed, EMBASE, BIOSIS, Cochrane central, and Google Scholar internet, last updated on May 30, 2019. Evaluated outcomes included the rate of wound healing and amputation. Dichotomous outcomes were described as risk ratios (RR) with 95% confidence intervals (CIs). Statistical analysis was performed with RevMan 5.0 software and STATA 10.0 software. RESULTS: Eight randomized controlled trial (RCT) studies were included in this study. The meta-analysis showed a lower amputation (RR 0.25, 95% CI 0.11 to 0.54, I 2 = 0) and a higher wound healing rate (RR 2.05, 95% CI 1.67 to 2.51, I 2 = 4) in the cell therapy group compared with control. CONCLUSION: This meta-analysis supports the effective role of stem cell therapy in promoting wound healing and decreasing rate of amputation in diabetic foot. In the future, more high quality and well-designed studies are need.

Autologous platelet-rich plasma treatment for patients with diabetic foot ulcers: a meta-analysis of randomized studies.

BACKGROUND: This study will explore the effectiveness and safety of autologous PRP in the treatment of patients with DFU. METHODS: The electronic databases of PubMed, EMBASE, BIOSIS, Cochrane central, and Google Scholar internet were searched updated on Jan 30, 2020. Evaluated outcomes included rate of complete ulcer healing, time to healing and adverse events. Statistical analysis was performed with RevMan 5.0 software and STATA 10.0 software. RESULTS: Ten RCTs with 456 patients were included in this study. The meta-analysis showed a higher complete ulcer healing rate (RR = 1.32, 95% CI 1.06 to 1.65, P = 0.01, I2 = 57%), a shorter healing time (MD = -23.42, 95% CI -37.33 to -9.51, P = 0.01, I2 = 78%), with no increasing the incidence of adverse events (RR = 0.48, 95% CI 0.22 to 1.05, P = 0.75, I2 = 0%) in PRP group compared with control. Mixed evidence was seen for publication bias, but analyses by using the trim-and-fill method did not appreciably alter results. CONCLUSION: Our findings suggest that autologous PRP may improve the complete ulcer healing rate, shorten the healing time, with no increasing the incidence of adverse events.

Assessment of the Risk Factors of Multidrug-Resistant Organism Infection in Adults With Type 1 or Type 2 Diabetes and Diabetic Foot Ulcer.

OBJECTIVES: To our knowledge, this is the first review to analyze the literature identifying risk factors for multidrug-resistant organism (MDRO) infection in patients with diabetic foot ulcer. The purpose of this study was to collect the currently published data to determine the most commonly and consistently identified risk factors for MDRO infection. METHODS: PubMed, MEDLINE, BIOSIS, Web of Science and the Cochrane Library electronic databases were searched. The last search updated was in September 2019. The evaluated outcomes included age, male sex, type of diabetes, diabetes duration, level of glycated hemoglobin, ulcer type, wound duration, ulcer size, ulcer grade, osteomyelitis, previous antibiotic therapy and previous hospitalization. The standard mean difference or the odds ratio (OR) was calculated for continuous or dichotomous data, respectively. The quality of the studies was assessed, and meta-analyses were performed with Cochrane Collaboration's RevMan 5.0 software. RESULTS: A total of 11 studies, including 1,229 patients provided evidence for 6 possible risk factors for MDRO infection. Ischemic ulcer (OR, 0.50; 95% confidence interval [CI], 0.35 to 0.71), ulcer size (standard mean difference, -0.27; 95% CI, -0.46 to -0.08), ulcer grade (OR, 0.36; 95% CI, 0.15 to 0.83), osteomyelitis (OR, 0.33; 95% CI, 0.25 to 0.45), previous antibiotic therapy (OR, 0.08; 95% CI, 0.04 to 0.14) and previous hospitalization (OR, 0.15; 95% CI, 0.08 to 0.28) were identified as risk factors for MDRO infection in patients with diabetic foot ulcer. CONCLUSIONS: Our meta-analysis indicated that ischemic ulcer, ulcer size, ulcer grade, osteomyelitis, previous antibiotic therapy and previous hospitalization were associated with MDRO infection in patients with diabetic foot ulcer.

Rapamycin Attenuates High Glucose-Induced Inflammation Through Modulation of mTOR/NF-κB Pathways in Macrophages.

Background: The NLRP3 inflammasome is one of the key contributors to impaired wound healing in diabetes. In this study, we assessed the role of rapamycin on high glucose-induced inflammation in THP-1-derived macrophages and investigated the underlying signaling mechanisms. Methods: THP-1-derived macrophages were treated with high glucose to induce NLRP3 inflammasome activation. The cells were pretreated with rapamycin, BAY 11-7082, or PDTC before exposure to HG. mTOR, NF-κB, and NLRP3 inflammasome expression were measured by western blotting. Results: We found that rapamycin reduced NLRP3 inflammasome activation in macrophages. Rapamycin reduced NLRP3 inflammasome activation by inhibiting mTOR phosphorylation and NF-κB activation. Moreover, mTOR siRNA inhibited NF-κB activation, leading to the suppression of NLRP3 inflammasome activation. Conclusion: Rapamycin can ameliorate high glucose-induced NLRP3 inflammasome activation by attenuating the mTOR/NF-κB signaling pathway in macrophages. Rapamycin may act as a possible therapeutic option for high glucose-induced inflammatory response in impaired wound healing in the future.

Advanced Glycation End Products (AGEs) Induce Apoptosis of Fibroblasts by Activation of NLRP3 Inflammasome via Reactive Oxygen Species (ROS) Signaling Pathway.

BACKGROUND Type 2 diabetes impairs the healing process and induces apoptosis of fibroblasts, which are thought to be involved in this process. We investigated the possible mechanisms involved in AGEs-induced apoptosis of human dermal fibroblasts. MATERIAL AND METHODS We examined the expression of apoptosis-related proteins in fibroblasts isolated from human diabetic wounds. Human dermal fibroblasts exposed to AGEs were used to study the links among apoptosis, ROS, and NLRP3 inflammasome activation. Signaling mechanisms were evaluated by preincubating the cells with appropriate inhibitors. Cleaved caspase-8, cleaved caspase-3, BAX, Bcl-2, and NLRP3 inflammasome expression were measured by Western blot analysis. ROS generation, cell viability, and cell apoptosis were assessed. RESULTS We observed a higher level of cleaved caspase-8 and cleaved caspase-3 expression in fibroblasts isolated from human diabetic wounds compared with controls. AGEs decreased the proliferation of cells in a concentration-dependent and time-dependent manner. The exposure of fibroblasts to AGEs significantly increased the number of cells in early and late apoptosis stages. AGES-induced human dermal fibroblasts showed high expressions of cleaved caspase3, cleaved caspase8, and Bax. Treatment with AGEs induced the expression of NLRP3, caspase-1, and ASC. AGES-induced apoptosis was blocked by BAY 11-7082, an inhibitor of the NLRP3 inflammasome. AGEs increased the production of ROS in fibroblasts, and its apoptogenic effect was blocked by NAC. CONCLUSIONS AGEs cause apoptosis of fibroblasts by inducing the generation of ROS and activating the NLRP3 inflammasome. In vivo experiments are needed to confirm these results.

Vitamin D and diabetic foot ulcer: a systematic review and meta-analysis.

We aimed to evaluate the association between vitamin D deficiency and diabetic foot ulcer (DFU) in patients with diabetes. Pubmed, EMBASE, BIOSIS, the Cochrane Library, and Web of Knowledge, last updated in July 2018, were searched. We assessed eligible studies for the association between vitamin D deficiency and DFU in diabetic patients. The mean difference (MD) or the odds ratio (OR) was calculated for continuous or dichotomous data respectively. Data were analyzed by using the Cochrane Collaboration's RevMan 5.0 software. Seven studies that involved 1115 patients were included in this study. There were significantly reduced vitamin D levels in DFU (MD -13.47 nmol/L, 95%CI -16.84 to -10.10; P = 0.34, I2 = 12%). Severe vitamin D deficiency was significantly associated with an increased risk of DFU (OR 3.22, 95%CI 2.42-4.28; P = 0.64, I2 = 0%). This is the first meta-analysis demonstrating the association between serum vitamin D levels and DFU. Severe vitamin D deficiency is significantly associated with an increased risk of DFU.

Association between Serum Cholesterol Level and Osteoporotic Fractures.

OBJECTIVE: Previous epidemiological studies have found an association between serum cholesterol level and bone mineral density. However, epidemiological studies evaluating the association between serum cholesterol level and the incidence of osteoporotic fracture are scant. Therefore, the objective of this study was to investigate whether serum cholesterol levels in Chinese participants aged 55 years or older was associated with an increased risk of osteoporotic fracture. MATERIALS AND METHODS: We performed a cross-sectional study, including 1,791 participants (62.1% postmenopausal women and 213 fractures). Standardized self-administered questionnaires, physical examination, laboratory tests, and dual-energy X-ray absorptiometry examination were performed. Multivariate-adjusted logistic regression models were used to evaluate associations between serum cholesterol [total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C)] levels and the osteoporotic fracture risk. RESULTS: After adjusting for potential confounding factors, there were no associations between per SD increase in TC and LDL level and an increased risk of osteoporotic fracture in total participants, and in men and women as individual groups. There was a significant association between per SD increase in HDL-C level and an increased risk of osteoporotic fracture in total participants [odds ratios (OR) 1.20, 95% confidence interval (CI) 1.03, 1.40, P = 0.023] and in women (OR 1.37, 95% CI 1.12, 1.68, P = 0.003), whereas no association was observed in men (OR 1.01, 95% CI 0.73, 1.40, P = 0.951). Additionally, we found a significant association between per SD increase in TG level and an increased risk of osteoporotic fracture in total participants (OR 1.20, 95% CI 1.04, 1.38, P = 0.015). In women, a nonlinear relationship was observed between per SD increase in TG level and an increased risk of osteoporotic fracture. The risk of osteoporotic fracture in women increased with TG level >1.64 mmol/L (OR 1.93, 95% CI 1.24, 3.00, P = 0.004). CONCLUSION: Among Chinese older adults, serum HDL-C level is significantly associated with a risk of osteoporotic fractures in women, and serum TG level is significantly associated with a risk of osteoporotic fractures in total participants and in women with TG >1.64 mmol/L.

Paeoniflorin regulates osteoclastogenesis and osteoblastogenesis via manipulating NF-κB signaling pathway both in vitro and in vivo.

The metabolic balance between synthesis and resorption of the bone is maintained by osteoblasts and osteoclasts, respectively. Identification of agents that stimulate bone formation and suppress excessive osteoclast formation, may aid in preventing and treating conditions like osteoporosis and periprosthetic loosening. Paeoniflorin is a natural product derived from Paeonia lactiflora Pall with anti-inflammatory, analgesic, and diuretic properties. However, the effect of paeoniflorin on osteoclastogenesis and osteoblastogenesis is unknown. Herein, we demonstrated that paeoniflorin has a dose-dependent suppressive action on RANKL-evoked osteoclast differentiation and bone resorption, achieved by inhibiting the NF-κB pathway and subunit p65 nuclear translocation. Simultaneously, paeoniflorin was also found to stimulate osteoblast differentiation and bone mineralization, in addition to rescuing TNFα-impaired osteoblastogenesis. At the molecular level, paeoniflorin was found to inhibit NF-κB transcriptional activity and stimulate osteoblastogenesis-related marker gene expression (ALP, osteocalcin, OPN and Runx2), a trend that was inhibited by p65 overexpression. In ovariectomized mice, paeoniflorin was found to improve osteoblast activity, inhibit osteoclast activity, and thus, reduce ovariectomy-induced osteoporosis. Our study demonstrated that paeoniflorin simultaneously suppressed osteoclastogenesis and facilitated osteoblastogenesis by manipulating the actions of NF-κB. Therefore, paeoniflorin may serve as an ideal therapeutic antidote for osteoporosis.

Experimental study of ASCs combined with POC-PLA patch for the reconstruction of full-thickness chest wall defects.

To explore the repairing effect of combination of adipose stem cells (ASCs) and composite scaffolds on CWR, the electrospun Poly 1, 8-octanediol-co-citric acid (POC)-poly-L-lactide acid (PLA) composite scaffolds were prepared, followed by in vitro and in vivo biocompatibility evaluation of the scaffolds. Afterwards, ASCs were seeded on POC-PLA to construct the POC-PLA-ASCs scaffolds, and the POC-PLA, POC-PLA-ASCs, and traditional materials expanded polytetrafluoroethylene (ePTFE) were adopt for CWR in New Zealand white (NZW) rabbit models. As results, the POC-PLA-ASCs patches possessed good biocompatibility as the high proliferation ability of cells surrounding the patches. Rabbits in POC-PLA-ASCs groups showed better pulmonary function, less pleural adhesion, higher degradation rate and more neovascularization when compared with that in other two groups. The results of western blot indicated that POC-PLA-ASCs patches accelerated the expression of VEGF and Collagen I in rabbit models. From the above, our present study demonstrated that POC-PLA material was applied for CWR successfully, and ASCs seeded on the sheets could improve the pleural adhesions and promote the reparation of chest wall defects.

Autophagy Inhibition Contributes to ROS-Producing NLRP3-Dependent Inflammasome Activation and Cytokine Secretion in High Glucose-Induced Macrophages.

BACKGROUND: Type 2 diabetes is a persistent inflammatory response that impairs the healing process. We hypothesized that stimulation with high glucose following a pro-inflammatory signal would lead to autophagy inhibition, reactive oxygen species (ROS) production and eventually to the activation of the Nod-like receptor protein (NLRP) -3. METHODS: Macrophages were isolated from human diabetic wound. We measured the expression of NLRP3, caspase1 and interleukin-1 beta (IL-1ß) by western blot and real-time PCR, and the surface markers on cells by flow cytometry. THP-1-derived macrophages exposed to high glucose were applied to study the link between autophagy, ROS and NLRP3 activation. LC3-II, P62, NLRP3 inflammation and IL-1ß expression were measured by western blot and real-time PCR. ROS production was measured with a Cellular Reactive Oxygen Species Detection Assay Kit. RESULTS: Macrophages isolated from diabetic wounds exhibited a pro-inflammatory phenotype, including sustained NLRP3 inflammasome activity associated with IL-1ß secretion. Our data showed that high glucose inhibited autophagy, induced ROS production, and activated NLRP3 inflammasome and cytokine secretion in THP-1-derived macrophages. To study high glucose-induced NLRP3 inflammasome signalling, we performed studies using an autophagy inducer, a ROS inhibitor and a NLRP3 inhibitor and found that all reduced the NLRP3 inflammasome activation and cytokine secretion. CONCLUSION: Sustained NLRP3 inflammasome activity in wound-derived macrophages contributes to the hyper-inflammation in human diabetic wounds. Autophagy inhibition and ROS generation play an essential role in high glucose-induced NLRP3 inflammasome activation and cytokine secretion in macrophages.

NLRP3 Inflammasome Expression and Signaling in Human Diabetic Wounds and in High Glucose Induced Macrophages.

Introduction. To investigate the contribution and mechanism of NLRP3 inflammasome expression in human wounds in diabetes mellitus and in high glucose induced macrophages. Methods. In the present study, we compared the expression of NLRP3 inflammasome in debridement wound tissue from diabetic and nondiabetic patients. We also examined whether high glucose induces NLRP3 inflammasome expression in cultures THP-1-derived macrophages and the influence on IL-1ß expression. Results. The expressions of NLRP3, caspase1, and IL-1ß, at both the mRNA and protein level, were significantly higher in wounds of diabetic patients compared with nondiabetic wounds (P < 0.05). High glucose induced a significant increase in NLRP3 inflammasome and IL-1ß expression in THP-1-derived macrophages. M1 macrophage surface marker with CCR7 was significantly upregulated after high glucose stimulation. SiRNA-mediated silencing of NLRP3 expression downregulates the expression of IL-1ß. Conclusion. The higher expression of NLRP3, caspase1, and secretion of IL-1ß, signaling, and activation might contribute to the hyperinflammation in the human diabetic wound and in high glucose induced macrophages. It may be a novel target to treat the DM patients with chronic wound.

ROS-activated NLRP3 inflammasome initiates inflammation in delayed wound healing in diabetic rats.

BACKGROUND: This study aims to evaluate the roles of reactive oxygen species (ROS) generation and inflammasome formation in the development of diabetic rat wound inflammation. MATERIALS AND METHODS: Diabetes was induced in rats by a single intraperitoneal injection of STZ, and a skin wound (2×2 cm2) was produced on the back. Diabetic animals were treated with NAC and Bay 11-7082 to block ROS and the NLRP3 inflammasome, respectively. Total mRNA and protein were isolated from wound tissue and subjected to real-time polymerase chain reaction, Western blot analyses and ELISA. We also assessed the rate of wound closure and time to wound healing. RESULTS: During healing, the diabetic rat exhibited increased ROS production, NLRP3 inflammasome activation and IL-1ß secretion. NAC was responsible for the inhibition of ROS production and NLRP3 inflammasome activation in diabetic rat wounds. We also found that blocking ROS generation improved the impaired healing pattern in diabetic rats and decreased the time for complete skin healing. CONCLUSION: These data suggest that excessive ROS production contributes to activating NLRP3-IL-1ß pathway events and impairs wound healing in a diabetic rat wound model.

Bone Morphogenetic Protein for the Healing of Tibial Fracture: A Meta-Analysis of Randomized Controlled Trials.

PURPOSE: To review the evidence from RCTs on clinical outcomes and benefit of acute tibial fracture and nonunion treated with and without BMPs. MATERIAL: We searched multiple databases (MEDLINE, EMABSE, BIOSIS and Cochrane central) as well as reference lists of articles and contacted authors. Evaluated outcomes included union rate, revision rate, hardware failure and infection. The weighted and standard mean difference (WMD and SMD) or the relative risk (RR) was calculated for continuous or dichotomous data respectively. The quality of the trial was assessed, and meta-analyses were performed with the Cochrane Collaboration's REVMAN 5.0 software. RESULTS: Eight RCTs involving 1113 patients were included. For acute tibial fracture, BMP group was associated with a higher rate of union (RR, 1.16; 95% CI, 1.04 to 1.30) and a lower rate of revision (RR, 0.68; 95% CI, 0.54 to 0.85) compared with control group. No significant differences were found in rate of hardware failure and infection. The pooled RR for achieving union for tibial fracture nonunion was 0.98 (95% CI, 0.86 to 1.13). There was no significant difference between the two groups in the rate of revision (RR, 0.48; 95% CI, 0.13 to 1.85) and infection (RR, 0.61; 95% CI, 0.37 to 1.02). CONCLUSION: Study on acute tibial fractures suggests that BMP is more effective that controls, for bone union and for decreasing the rate of surgical revision to achieve union. For the treatment of tibial fracture nonunion, BMP leads to similar results to as autogenous bone grafting. Finally, well-designed RCTs of BMP for tibial fracture treatment are also needed.