Injective hydrogel loaded with liposomes-encapsulated MY-1 promotes wound healing and increases tensile strength by accelerating fibroblast migration via the PI3K/AKT-Rac1 signaling pathway.

Failed skin wound healing, through delayed wound healing or wound dehiscence, is a global public health issue that imposes significant burdens on individuals and society. Although the application of growth factor is an effective method to improve the pace and quality of wound healing, the clinically approved factors are limited. Parathyroid hormone (PTH) demonstrates promising results in wound healing by promoting collagen deposition and cell migration, but its application is limited by potentially inhibitory effects when administered continuously and locally. Through partially replacing and repeating the amino acid domains of PTH(1-34), we previously designed a novel PTH analog, PTH(3-34)(29-34) or MY-1, and found that it avoided the inhibitory effects of PTH while retaining its positive functions. To evaluate its role in wound healing, MY-1 was encapsulated in liposomes and incorporated into the methacryloyl gelatin (GelMA) hydrogel, through which an injectable nanocomposite hydrogel (GelMA-MY@Lipo, or GML) was developed. In vitro studies revealed that the GML had similar properties in terms of the appearance, microstructure, functional groups, swelling, and degradation capacities as the GelMA hydrogel. In vitro drug release testing showed a relatively more sustainable release of MY-1, which was still detectable in vivo 9 days post-application. When the GML was topically applied to the wound areas of rat models, wound closure as well as tensile strength were improved. Further studies showed that the effects of GML on wound repair and tensile strength were closely related to the promotion of fibroblast migration to the wound area through the controlled release of MY-1. Mechanically, MY-1 enhanced fibroblast migration by activating PI3K/AKT signaling and its downstream molecule, Rac1, by which it increased fibroblast aggregation in the early stage and resulting in denser collagen deposition at a later time. Overall, these findings demonstrated that the nanocomposite hydrogel system promoted skin wound healing and increased tensile strength, thus offering new potential in the treatment of wound healing.

Human Parathyroid Hormone Analog (3-34/29-34) promotes wound re-epithelialization through inducing keratinocyte migration and epithelial-mesenchymal transition via PTHR1-PI3K/AKT activation.

BACKGROUND: Re-epithelialization is important in the process of wound healing. Various methods have been identified to expedite the process, but their clinical application remains limited. While parathyroid hormone (PTH) has shown promising results in wound healing due to its role in promoting collagen deposition and cell migration, application is limited by its potentially inhibitive effects when being continuously and locally administrated. Herein, we developed a novel PTH analog, Human parathyroid hormone (hPTH) (3-34/29-34) (henceforth MY-1), by partially replacing and repeating the amino acid sequences of hPTH (1-34), and evaluated its effect on skin wound re-epithelialization. METHODS: CCK-8, colony formation unit assay, and Ki67 immunofluorescent staining were performed to evaluate the effect of MY-1 on HaCaT cell proliferation. Then, wound scratch assay, Transwell assay and lamellipodia staining were carried out to evaluate the effect of MY-1 on cell migration. Moreover, the epithelial-mesenchymal transition (EMT) markers were measured using qPCR and western blot analysis. For in-vivo drug delivery, gelatin methacryloyl (GelMA) hydrogel was employed to load the MY-1, with the physicochemical characteristics evaluated prior to its application in wound models. Then, MY-1's role in wound healing was determined via acute skin wound models. Finally, the mechanism that MY-1 activated was also detected on HaCaT cells and in-vivo wound models. RESULTS: In-vitro, MY-1 accelerated the migration and EMT of HaCaT cells, while having little effect on cell proliferation. GelMA and MY-1-incorporated GelMA hydrogels showed similar physicochemical characteristics and were used in the in-vivo studies, where the results revealed that MY-1 led to a stronger re-epithelialization by inducing basal keratinocyte migration and EMT. Further studies on in-vivo wound models and in-vitro HaCaT cells revealed that MY-1 regulated cell migration and EMT through activating PI3K/AKT signaling. The parathyroid hormone type 1 receptor (PTHR1), the main receptor of PTH, was found to be the upstream of PI3K/AKT signaling, through interfering PTHR1 expression with a small interference RNA following detection of the PI3K/AKT activation. CONCLUSION: Collectively, our study demonstrated that MY-1 accelerates skin wound re-epithelialization by inducing keratinocyte migration and EMT via PTHR1-PI3K/AKT axis activation. Video Abstract.

Antibiotic-impregnated calcium sulfate for the treatment of pediatric hematogenous osteomyelitis.

BACKGROUND: Antibiotic-impregnated calcium sulfate has excellent curative efficacy in chronic osteomyelitis. However, its curative efficacy in pediatric hematogenous osteomyelitis has not been sufficiently studied. The purpose of this study was to evaluate the curative effects of antibiotic-impregnated calcium sulfate in the treatment of pediatric hematogenous osteomyelitis. METHODS: Overall, twenty-one pediatric patients with hematogenous osteomyelitis treated at our hospital between 2013 and 2018 were included for assessment. The clinical history, clinical manifestation, infection recurrence rate, sinus leakage, incision leakage, pathological fractures, bone growth and surgical procedures were analyzed. RESULTS: The infection recurrence rate was 0% (0/21) at a minimum of 31 months (range 31 to 91 months) of follow-up. Postoperative incision leakage was found in one pediatric patient. Osteolysis was found in one pediatric patient. Acceleration of bone growth occurred in one pediatric patient. Retardation of bone growth occurred in one pediatric patient. Genu valgus deformity occurred in one pediatric patient. CONCLUSIONS: Although noninfectious complications occurred, the curative effect of antibiotic-impregnated calcium sulfate in pediatric hematogenous osteomyelitis was satisfactory.

Melatonin Accelerates Osteoporotic Bone Defect Repair by Promoting Osteogenesis-Angiogenesis Coupling.

Previous studies have revealed that melatonin could play a role in anti-osteoporosis and promoting osteogenesis. However, the effects of melatonin treatment on osteoporotic bone defect and the mechanism underlying the effects of melatonin on angiogenesis are still unclear. Our study was aimed to investigate the potential effects of melatonin on angiogenesis and osteoporotic bone defect. Bone marrow mesenchymal stem cells (BMSCs) were isolated from the femur and tibia of rats. The BMSC osteogenic ability was assessed using alkaline phosphatase (ALP) staining, alizarin red S staining, qRT-PCR, western blot, and immunofluorescence. BMSC-mediated angiogenic potentials were determined using qRT-PCR, western blot, enzyme-linked immunosorbent assay, immunofluorescence, scratch wound assay, transwell migration assay, and tube formation assay. Ovariectomized (OVX) rats with tibia defect were used to establish an osteoporotic bone defect model and then treated with melatonin. The effects of melatonin treatment on osteoporotic bone defect in OVX rats were analyzed using micro-CT, histology, sequential fluorescent labeling, and biomechanical test. Our study showed that melatonin promoted both osteogenesis and angiogenesis in vitro. BMSCs treated with melatonin indicated higher expression levels of osteogenesis-related markers [ALP, osteocalcin (OCN), runt-related transcription factor 2, and osterix] and angiogenesis-related markers [vascular endothelial growth factor (VEGF), angiopoietin-2, and angiopoietin-4] compared to the untreated group. Significantly, melatonin was not able to facilitate human umbilical vein endothelial cell angiogenesis directly, but it possessed the ability to promote BMSC-mediated angiogenesis by upregulating the VEGF levels. In addition, we further found that melatonin treatment increased bone mineralization and formation around the tibia defect in OVX rats compared with the control group. Immunohistochemical staining indicated higher expression levels of osteogenesis-related marker (OCN) and angiogenesis-related markers (VEGF and CD31) in the melatonin-treated OVX rats. Then, it showed that melatonin treatment also increased the bone strength of tibia defect in OVX rats, with increased ultimate load and stiffness, as performed by three-point bending test. In conclusion, our study demonstrated that melatonin could promote BMSC-mediated angiogenesis and promote osteogenesis-angiogenesis coupling. We further found that melatonin could accelerate osteoporotic bone repair by promoting osteogenesis and angiogenesis in OVX rats. These findings may provide evidence for the potential application of melatonin in osteoporotic bone defect.

Antibiotic-Impregnated Calcium Sulfate vs. Wound Irrigation-Suction to Treat Chronic Calcaneal Osteomyelitis.

BACKGROUND: Chronic osteomyelitis of calcaneus is not rare but is very hard to treat. Irrigation-suction and antibiotic-impregnated calcium sulfate following debridement are commonly used in managing chronic osteomyelitis, but their effects have rarely been compared. We aimed to compare the effectiveness of antibiotic-impregnated calcium sulfate with irrigation-suction in the treatment of patients with chronic calcaneal osteomyelitis. METHODS: From January 2011 to June 2018, adult patients at our institute with chronic osteomyelitis receiving treatment of either antibiotic-impregnated calcium sulfate (CS group) or irrigation-suction (IS group) following thorough debridement were screened and selected according to the inclusion and exclusion criteria. The clinical presentation, laboratory tests, complications, and the ultimate single-staged cure rate and recurrence were compared. RESULTS: A total of 61 patients, including 41 in the CS group and 20 in the IS group, were included in our study. Of the patients, 85.4% in the CS group and 60.0% in the IS group (P = .006) were successfully cured in the single stage, respectively, without infection recurrence. Lower infection recurrence rates with shorter hospital stay were found in the CS group than the IS group. Inflammatory biomarkers after surgery with both treatments were slightly decreased and not significantly different from preoperative or between-groups postoperative. Exudate from incision was found primarily in the CS group. CONCLUSION: This study demonstrates that both antibiotic-impregnated calcium sulfate and irrigation-suction after careful and thorough surgical debridement are generally effective in treating chronic calcaneal osteomyelitis. Antibiotic-impregnated calcium sulfate achieved a higher single-staged cure rate but was associated with an increased postoperative wound exudate. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Culture-negative chronic hematogenous osteomyelitis in a two months old girl: a case report.

BACKGROUND: Previous articles have focused on the diagnosis and treatment of acute hematogenous osteomyelitis. Here, we present a case of chronic hematogenous osteomyelitis in a 2-month-old girl. The diagnostic procedure was unusual and difficult due to negative culture results. CASE PRESENTATION: A girl aged 2 months and 23 days had fever and swelling in her right lower leg for 7 days. On the basis of her medical history, physical, and histological examination results; and radiologic and magnetic resonance imaging findings, a diagnosis of chronic osteomyelitis was made. The patient underwent surgical treatment and was discharged successfully. The patient showed good recovery and no sequelae at the 12-month follow-up. CONCLUSION: Hematogenous osteomyelitis in babyhood is different from that at any other age. Hematogenous osteomyelitis-related bone destruction in babyhood is more serious and occurs faster. The transition from acute hematogenous osteomyelitis to chronic hematogenous osteomyelitis takes only 7 days. To the best of our knowledge, this chronic hematogenous osteomyelitis patient is the youngest ever reported.

One-stage debridement and bone transport versus first-stage debridement and second-stage bone transport for the management of lower limb post-traumatic osteomyelitis.

BACKGROUND: Treatment of lower limb post-traumatic osteomyelitis used to be a staged process, with radical debridement of bone and soft tissues at first stage, followed by a second-stage limb reconstruction operation to restore the limb integrity. Some studies recently reported that achieving infection eradication and limb reconstruction at single-stage seems to be an effective method for lower limb infection, but a comparative study remains lacking. This study aims to compare the results of radical debridement combined with a first/second-staged osteotomy and bone transport, for the management of lower limb post-traumatic osteomyelitis. METHODS: From January 2013 to June 2018, a total of 102 patients with lower limb post-traumatic osteomyelitis met the criteria were included for analysis, in which 70 patients received one-stage debridement, antibiotic-loaded implantation, metaphysis osteotomy and bone transport were named as one-stage group, while 32 patients with first-stage debridement and antibiotic-loaded calcium sulfate implantation, second-stage osteotomy and bone transport were devised as two-stage group. The outcomes of hospitalization (hospital stay, costs of treatment, surgical time, antibiotic usage) and follow-up (infection-free, treatment failure, infection recurrence, external fixation index (EFI) and docking site union) between the two groups were retrospectively compared. RESULTS: For outcomes of hospitalization, patients in the one-stage group had batter results on hospital stay (18.2 days versus 28.9 days, P â€‹< â€‹0.05), surgical time (164.8 â€‹min versus 257.4 â€‹min, P â€‹< â€‹0.05), cost of treatment (¥101726.1 versus ¥126718.8, P â€‹< â€‹0.05) and the course of antibiotic usage (10.3 days versus 12.0 days, P â€‹< â€‹0.05). During the follow-up, 87.1% (61/70) patients in the one-stage group compared to 93.8% (30/32) patients in the two-stage group achieved infection-free (P â€‹> â€‹0.05) without any additional debridement operation. 94.3% (66/70) patients in the one-stage group earned wound healing after the operation, comparing to 96.9% (31/32) patients healed in the two-stage group (P â€‹> â€‹0.05). Uncontrolled infection was observed on 4 (5.7%) patients in the one-stage group and 1 (3.1%) patients in the two-stage group (P â€‹> â€‹0.05), with a result of three achieved infection free in the one-stage group and one patient suffered from amputation in each group respectively. 5 (7.2%) patients in the one-stage group and 1 (3.2%) patient in the two-stage group encountered with infection recurrence (P â€‹> â€‹0.05) and were well-managed with re-debridement and antibiotics usage. Significance was not found between two groups on EFI (74.8 days/cm versus 69.0 days/cm, P â€‹> â€‹0.05) and docking site nonunion rate (14.5% versus 18.9%, P â€‹> â€‹0.05), indicating that bone transport in different stages played a less essential role on bone generation process. The other complications, such as prolonged aseptic drainage [24.3% (17/70) versus 21.9% (7/32)], re-fracture [5.8% (4/69) versus 3.2% (1/31)], pin-tract infection [23.2% (16/69) versus 19.4% (6/31)], joint stiffness and deformity [26.1% (18/69) versus 32.3% (10/31)], also showed less significance when comparing between two groups (P â€‹> â€‹0.05), suggesting that different transport stages play little role on complications formation. CONCLUSIONS: One-stage radical debridement and bone transport was proven to be a safe and effective method for treating static (or near static) lower limb osteomyelitis. TRANSLATIONAL POTENTIAL STATEMENT: Translational potential statement One-stage debridement and bone transport is sample, effective and time-saving, with similar complications compared to conventional two-stage protocol. This treatment protocol might provide an alternative for the treatment of static (or near static) lower limb osteomyelitis.

Unprecedented tibial bone lengthening of 33.5 cm by distraction osteogenesis for the reconstruction of a subtotal tibial bone defect. A case report and literature review.

BACKGROUND: We present a case of an immense unprecedented tibial bone lengthening of 33.5 cm. The management of chronic osteomyelitis of the right tibia with subtotal tibial bone defect, talus defect and equinus ankle deformity. We demonstrate limb reconstruction by distraction osteogenesis and correction of ankle deformity with the Ilizarov technique. Limb salvage was preferred as an alternative to amputation to restore basic limb function. CASE PRESENTATION: A 16-year-old male patient fell and injured his right lower leg. He attempted to treat the symptoms with traditional home remedies. During 15 months of self-treating, he developed osteomyelitis of the right tibia and had lost function in his foot. Radiology revealed immense bone defect of the right tibia, including talus bone defect and equinus deformity of the calcaneus. The patient's right tibia was non weight-bearing, had drainage sinus just below his knee and a large scar anteriorly along the entire length of the tibia. CONCLUSION: Upon completion of treatment, the patient was able to avoid amputation of his leg with partially restored function for weight-bearing. He carried himself without assistance after 3 years of lost function in his right leg. Tibial bone distraction osteogenesis of 33.5 cm was done after 90% of the tibial length was defected. To the best of our best knowledge, this case is one of a kind to achieve distraction of tibial bone to such length.

Intramedullary reaming and irrigation and antibiotic-loaded calcium sulfate implantation for the treatment of infection after intramedullary nailing: a retrospective study of 19 cases.

BACKGROUND: The incidence of intramedullary infection is increasing with increased use of intramedullary fixation for long bone fractures. However, appropriate treatment for infection after intramedullary nailing is unclear. The purpose of this study was to report the results of our treatment protocol for infection after intramedullary nailing: intramedullary nail removal, local debridement, reaming and irrigation, and antibiotic-loaded calcium sulfate implantation with or without segmental bone resection and distraction osteogenesis. METHODS: We retrospectively reviewed the records of patients with an infection after intramedullary nailing treated from 2014 to 2017 at our center. Patients with follow-up of less than 24 months, received other treatment methods, or those with serious medical conditions were excluded from the analysis. Patients met the criteria were treated as described above, followed by distraction osteogenesis in 9 cases to repair bone defect. The infection remission rate, infection recurrence rate, and post-operative complication rates were assessed. RESULTS: A total of 19 patients were included in the analysis. All of patients had satisfactory outcomes with an average follow-up of 38.1 ± 9.4 months (range, 24 to 55 months). Eighteen patients (94.7%) achieved infection remission; 1 patient (5.3%) developed a reinfection that resolved after repeat debridement. Nine patients with bone defects (average size 4.7 ± 1.3 cm; range, 3.3 to 7.6 cm) were treated with bone transport which successfully restored the length of involved limb. The mean bone transport duration was 10.7 ± 4.0 months (range, 6.7 to 19.5 months). The majority of patients achieved full weight bearing and became pain free during the follow-up period. Postoperative complications mainly included prolonged aseptic drainage (7/19; 36.8%), re-fracture (1/19; 5.3%) and joint stiffness, which were successfully managed by regular dressing changes and re-fixation, respectively. CONCLUSION: Intramedullary nail removal, canal reaming and irrigation, and antibiotic-loaded calcium sulfate implantation (with or without distraction osteogenesis) is effective for treating infections after intramedullary nailing.

Single-stage treatment of chronic localized tibial osteomyelitis with local debridement and antibiotic-loaded calcium sulfate implantation: a retrospective study of 42 patients.

BACKGROUND: Although various methods have been introduced, the management of chronic tibial osteomyelitis remains a challenge. This study aims to assess a combined treatment method, local debridement combined with antibiotic-loaded calcium sulfate implantation, for the management of the local (Cierny-Mader type III) tibial osteomyelitis. METHODS: Forty-two patients (43 limbs) with type III tibial osteomyelitis, from January 2012 to December 2018, who received the treatment method mentioned above were included in the study. The infection remission rate, recurrence rate, complications rate, and bone healing rate were respectively analyzed. RESULTS: With a mean follow-up of 42.8 months, 38 limbs (37 patients) (88.4%, 38/43) achieved infection remission without recurrence. Among those patients pain, limitation of movement, sinus tracts, topical redness, and swelling were generally eliminated. Only 4 patients felt slight pain after a long-distance walk, while another 6 patients showed minor but acceptable discomfort in affected limbs. Five patients (11.6%) suffered from osteomyelitis recurrence that required secondary surgical and medical treatment, but no amputation was necessary to eliminate the infection. Prolonged aseptic drainage was the most frequent complication that was observed in 13 patients (30.0%). They were successfully managed by appropriate wound caring in 10 patients and by surgical intervention, months later, in 3 patients. According to the final X-ray examination, bone losses caused by local debridement were generally repaired, though the shape of the tibia was not well-restored to its initial form in 17 limbs. No fracture was recorded during follow-up. CONCLUSION: Local debridement combined with antibiotic-loaded calcium sulfate implantation is effective and safe in a single-stage treatment of chronic Cierny-Mader III tibial osteomyelitis.

Extensive eggshell-like debridement technique plus antibiotic-loaded calcium sulphate for one-stage treatment of chronic calcaneal osteomyelitis.

BACKGROUND: Management of chronic calcaneal osteomyelitis is challenging. At present, there is still no widely accepted, simple, and effective surgical method to eradicate the infection and prevent osteomyelitis recurrence. The objective of this study was to assess the outcomes of one-stage treatment of chronic calcaneal osteomyelitis with a shape-preserving debridement technique combined with antibiotic-loaded calcium sulphate. METHODS: Between 2012 and 2018, 33 patients (33 limbs) with chronic calcaneal osteomyelitis were treated with a novel debridement technique, named "eggshell-like debridement", plus antibiotic-impregnated calcium sulphate. The infection remission rate, recurrence rate, and amputation rate were analyzed. The American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score was used to assess postoperative hindfoot function. RESULTS: 26 patients (81.8%) achieved infection remission without recurrence. In the patients with osteomyelitis remission, pain, limitation of movement, sinus tracts, and typical redness and swelling were generally eliminated. Most of the patients could tolerate full weight-bearing without pain. The average AOFAS ankle and hindfoot score was 88 points (range, 67-100 points), implying the foot function was mostly restored. 6 patients (18.2%) had osteomyelitis recurrence but no amputation was required to elimilate the infection. CONCLUSIONS: Eggshell-like debridement combined with antibiotic-loaded calcium sulphate is an effective method for one-stage management of chronic calcaneal osteomyelitis. With the application of this technique, secondary autogenous bone or muscle flap grafts are unnecessary. The surgical procedure can be simplified whlie the hindfoot function is well preserved.

Infected bone resection plus adjuvant antibiotic-impregnated calcium sulfate versus infected bone resection alone in the treatment of diabetic forefoot osteomyelitis.

BACKGROUND: Managing with diabetic foot osteomyelitis (DFO) is challenging. Even after infective bone resection and thorough debridement, DFO is still difficult to cure and has a high recurrence rate. This retrospective study aims to compare the outcomes of two treatment methods, infected bone resection combined with adjuvant antibiotic-impregnated calcium sulfate and infected bone resection alone, for the treatment of diabetic foot osteomyelitis. METHODS: Between 2015 to 2017, 48 limbs (46 patients) with DFO met the criteria were included for assessment. 20 limbs (18 patients) were included in the calcium sulfate group (the CS group) in which vancomycin and/or gentamicin-impregnated calcium sulfate was used as an adjuvant after infected bone resection while 28 limbs (28 patients) as the control group were undergone infected bone resection only. Systemic antibiotics, postoperative wound care and offloading were continued to be applied following surgery in both groups. The time to healing, healing rate, recurrence rate and amputation rate were compared between the two groups. RESULTS: In total, 90% (18/20) limbs in the CS group as compared to 78.6% (22/28) infected limbs in the control group went to heal (P = 0.513). The Mean time to healing was 13.3 weeks in the CS group and 11.2 weeks in control group (P = 0.132). Osteomyelitis recurrence rate was 0% (0/18) in the CS group and 36.4% (8/22) in the control group (P = 0.014). Postoperative leakage in calcium sulfate group was 30.0% (6/20) with a mean duration of 8.5 weeks. Amputation rate in the control group was 7.1% (2/28) compared to 0% (0/20) in the CS group (P = 0.153). CONCLUSIONS: Antibiotic-impregnated calcium sulfate as an adjuvant prevents the recurrence of DFO but cannot improve the healing rate, reduce the postoperative amputation rate or shorten the time to healing. Prolonged postoperative leakage as the most common complication can be managed with regular dressing. LEVEL OF EVIDENCE: III, Retrospective Comparative Study.