Coculture of adipose-derived mesenchymal stem cells/macrophages on decellularized placental sponge promotes differentiation into the osteogenic lineage.

BACKGROUND: Several factors like three-dimensional microstructure, growth factors, cytokines, cell-cell communication, and coculture with functional cells can affect the stem cells behavior and differentiation. The purpose of this study was to investigate the potential of decellularized placental sponge as adipose-derived mesenchymal stem cells (AD-MSCs) and macrophage coculture systems, and guiding the osteogenic differentiation of stem cells. METHODS: The decellularized placental sponge (DPS) was fabricated, and its mechanical characteristics were evaluated using degradation assay, swelling rate, and pore size determination. Its structure was also investigated using hematoxylin and eosin staining and scanning electron microscopy. Mouse peritoneal macrophages and AD-MSCs were isolated and characterized. The differentiation potential of AD-MSCs co-cultured with macrophages was evaluated by RT-qPCR of osteogenic genes on the surface of DPS. The in vivo biocompatibility of DPS was determined by subcutaneous implantation of scaffold and histological evaluations of the implanted site. RESULTS: The DPS had 67% porosity with an average pore size of 238 µm. The in vitro degradation assay showed around 25% weight loss during 30 days in PBS. The swelling rate was around 50% during 72 h. The coculture of AD-MSCs/macrophages on the DPS showed a significant upregulation of four differentiation osteogenic lineage genes in AD-MSCs on days 14 and 21 and a significantly higher mineralization rate than the groups without DPS. Subcutaneous implantation of DPS showed in vivo biocompatibility of scaffold during 28 days follow-up. CONCLUSIONS: Our findings suggest the decellularized placental sponge as an excellent bone substitute providing a naturally derived matrix substrate with biostructure close to the natural bone that guided differentiation of stem cells toward bone cells and a promising coculture substrate for crosstalk of macrophage and mesenchymal stem cells in vitro.

Evaluation of the short-term outcomes of anatomic ACL reconstruction with hamstring autograft in patients with generalized joint laxity: A retrospective case-control study.

PURPOSE: The outcomes of anterior cruciate ligament reconstruction (ACLR) in patients with generalized joint laxity (GJL) are not clearly understood. In this study, we compared the outcomes of ACLR with quadruple hamstring autograft between GJL and non-GJL patients. METHODS: In a retrospective case-control study, 36 patients with GJL, according to the Beighton and Horan Joint Mobility Index, who underwent ACLR surgery, were included. Forty-four group-matched non-GJL patients were included in the control group. The mean follow-up of the patients was 20.65 ± 6.93 months. The outcomes of ACLR were evaluated by the Lachman test, pivot shift test, anterior tibial translation and KT-1000 side-to-side difference, and International Knee Documentation Committee (IKDC) scale. RESULTS: The results of the Lachman and pivot shift test were not significantly different between the GJL and non-GJL patients (P = 0.67 and P = 0.27, respectively). The mean anterior tibial translation was 7.06 ± 1.41 mm in the GJL group and 6.11 ± 1.53 mm in the non-GJL group (P = 0.006). The mean KT-1000 side-to-side difference was 2.25 ± 1.31 mm in the case and 2.5 ± 1.44 mm in the control group (P = 0.42). The mean IKDC score of the patients was not significantly different between the GJL and non-GJL groups (66.1 ± 20.6 vs. 69.9 ± 16.1, P = 0.35). ACLR failure occurred in 2 (5.5%) patients of the GJL group and no patients of the control group (P = 0.21). CONCLUSION: The present findings suggest ACLR with quadruple hamstring autograft as an adequate treatment for GJL patients, at least in short-term follow-up.

Spinopelvic Parameters as Risk Factors of Nonspecific Low Back Pain: A Case-Control Study.

Background: The effect of spinopelvic alignment on low back pain (LBP) incidence has been studied in many investigations. However, the interrelation between spinopelvic parameters and LBP is poorly understood. In particular, it is unknown whether particular patterns of spinopelvic parameters render nonspecific LBP. In this study, we aimed to evaluate the role of spinopelvic parameters as risk factors of nonspecific LBP. Methods: In this case-control study, spinopelvic parameters, including lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI), were compared between 148 patients with nonspecific LBP and 148 healthy controls. Demographic characteristics of the patients, such as age, gender, occupation, smoking, diabetes mellitus, and body mass index (BMI), were recorded as confounders. Spinopelvic parameters were assessed using radiographic findings in 2 groups. The analysis was done once as univariate (Kolmogorov-Smirnov test) and once as multivariate (multivariate logistic regression) analysis. Results: Univariate analysis showed that female gender, higher BMI, smoking, and blue-collar jobs were associated with a higher risk of nonspecific LBP. LL, SS, and PI, but not PT, were all greater in LPB patients in the univariate analysis regarding the spinopelvic parameters. Multivariate analysis showed female gender (odds ratio adjusted (ORAdj) = 4.26 [95% CI, 2.11-9.58]; P = 0.001) and LL (ORAdj = 1.58; [95% CI, 1.18-3.22]; P = 0.026) were predictable risk factors for Nonspecific LBP. Conclusion: Spinopelvic parameters, particularly LL, could be considered as risk factors of nonspecific LBP so that a more significant LL might indicate a greater risk of LBP. However, the role of other parameters in this association could not be neglected.

Evaluation of early complications, outcome, and mortality in Coronavirus Disease 2019 (COVID-19) infection in patients who underwent orthopedic surgery.

BACKGROUND: A higher mortality and morbidity rate has been reported in COVID-19 patients undergoing surgery. To reduce the morbidity and mortality rate in COVID-19 patients undergoing orthopedic procedures, we aimed to increase the threshold for surgical planning. METHODS: In a prospective cohort study, COVID-19 patients who underwent elective or emergent orthopedic surgery in three orthopedic surgery centers from February 2020 to September 2020 were included. In this period, 6751 patients were scheduled for orthopedic surgery. To increase surgical threshold planning, all patients with grade 5 of the American Society of Anesthesiologists (ASA) classification and patients with COVID-19 related moderate to severe pulmonary involvement were identified as high-risk patients and were excluded. RESULTS: 35 deaths occurred during the study. The frequency of deaths was significantly higher in patients with COVID-19, 6 (9.4%) than patients without COVID-19, 29 (0. 43%). The average hospitalization stay was 12.8 ± 12.1 days. The odds ratio (OR) for death was significantly higher in patients with COVID-19 than patients without COVID-19. [OR: 8.13, Confidence interval 95% (CI95%) (5.02-11.25), P: 0.001]. Four (6.3%) COVID-19-associated complications were recorded in this series that all were respiratory failure requiring unexpected postoperative ventilation. Twenty surgical complications (31.3%) were recorded. The odds ratio for ICU admission was significantly higher in patients with COVID-19 than patients without COVID-19. [OR: 5.46, CI 95% (2.68-8.68), P: 0.001]. CONCLUSIONS: An increased threshold for orthopedic surgery is suggested for COVID-19 patients with a mortality rate of 9.3%, which is less than the mortality rate in other studies. Level of evidence III.

The distance between new and previous incisions does not affect skin necrosis in total knee arthroplasty: a parallel-randomized controlled clinical trial.

BACKGROUND: To avoid skin necrosis, an 8 cm distance between the new and previous incision is recommended in patients undergoing total knee arthroplasty (TKA). It was hypothesized that making a new incision less than 8 cm of the prior scar does not increase the risk of skin complications, and the new incision can be made anywhere, regardless of the distance from the previous scar. This study investigated how making a new incision, irrespective of the previous scars, affects skin necrosis. METHODS: In this parallel, randomized clinical trial, by simple randomization method using a random number table, 50 patients with single longitudinal knee scars were randomly assigned to two groups with a 1:1 ratio and 25 participants in each group. Patients with a minimum age of 60 and a single longitudinal previous scar on the knee were included. The exclusion criteria were diabetes mellitus, hypertension, morbid obesity, smoking, vascular disorders, cardiopulmonary disorders, immune deficiencies, dementia, and taking steroids and angiogenesis inhibitors. TKA was performed through an anterior midline incision, regardless of the location of the previous scar in the intervention group. TKA was performed with a new incision at least 8 cm distant from the old incision in the control group. Skin necrosis and scar-related complications were evaluated on the first and second days and first, second, and fourth weeks after the surgery. Knee function was assessed using the Knee Society Score (KSS) six months after the surgery. RESULTS: The baseline characteristics of the groups did not differ significantly. The average distance from the previous scar was 4.1 ± 3.2 cm in the intervention group and 10.2 ± 2.1 cm in the control group. Only one patient in the control group developed skin necrosis (P-value = 0.31). Other wound-related complications were not observed in both groups. The mean KSS was 83.2 ± 10.2 and 82.9 ± 11.1 in the intervention and control groups, respectively (P-value = 0.33). CONCLUSIONS: It is possible that in TKA patients, the new incision near a previous scar does not increase the risk of skin necrosis and other complications.

Comparison of Students' Attitudes about the Effectiveness of Algorithm-based Education with Lecture-based Education.

Background: Training is a complex process, especially when the students are being prepared for patient's management. Therefore, the development of effective teaching methods is critical for to improvement of learning and communication between the content and concepts. In algorithm-based education, more focus is placed on more involvement of students in the subject, thereby providing a better understanding of the concept. In this study, we compared students' attitudes about the effectiveness of algorithm-based education (education based on the patient's complaints and symptoms) with lecture-based education in the learning ability of the medical students presented in the clinical course of the orthopedic group. Methods: This research is a single-group quasi-experimental study; we assessed the students' attitudes on a five-point Likert scale questionnaire with confirmed validity and reliability. The scores of two teaching methods were assessed after the training course, which was presented using the algorithmic method for selective titles and lectures for the other titles. Data were analyzed on SPSS software using a paired t-test. Results: A total of 220 internship medical students, including 58.7% of girls with a mean age of 22.9 ± 1.19 years, participated in the study. The mean score of the questions was 3.92±0.54 and 2.17±0.58 in the algorithmic and the lecture training, respectively. After comparing the results with a paired t-test, there was a significant difference between students' attitudes toward the two teaching methods (p ˂ 0.001), so the students' attitude was more positive toward the algorithm-based method. Conclusion: For the education of medical students, algorithm-based training is more efficacious compared to traditional methods such as lecture-based training.

A Study of Characteristic Features and Diagnostic Roles of X-ray and MRI in Calcifying Tendinitis of the Shoulder.

Background: Calcifying tendinitis (CT) is an enigmatic lesion with several obscure aspects and it is a common disorder of the upper extremity characterized by the presence of calcifications in rotator cuff tendons and synovial tissues. In this study, we aimed to review the demographic and clinical characteristics, as well as radiologic and treatment history in CT patients who were referred with shoulder pain. Methods: In this cross-sectional study, a total of 146 patients who were referred with a shoulder CT were included. The definitive diagnosis was based on a combination of plain radiograph and magnetic resonance imaging (MRI). A predesigned independent t test was used to capture demographic and clinical data, as well as radiologic and treatment histories, and a chi-square test was utilized to assess the statistical correlation between qualitative variables. Results: The median age of the patients was 42.5 years. The female to male ratio was 2.3 to 1. The complaint of restricted shoulder movement was recorded in 107 (73.3%) patients and more frequently in women (p = 0.042). Night pain was present in 109 (74.7%) patients. The current and previous diagnoses matched in 36.1% (13 out of 36) of patients who only had MRI and in 63.6% (35 out of 55) patients who had both MRI and plain radiograph with them. Supraspinatus tendon was the main site of calcified deposition 65% (95 out of 146). Conclusion: CT is frequent at the age of around 40 and in the female gender. The diagnosis should be based on a combination of radiography and MRI and not based on MRI alone. The efficacy of different conservative treatments remains to be unwrapped.

Calcaneostop Provides Favorable Short-term Outcomes in Patients With Flexible Flatfoot.

Background: Flatfoot is a relatively frequent deformity seen in almost 5% of children. It is classified into flexible and rigid flatfoot. Symptomatic flexible flatfoot (FFF) can be managed using several procedures, and calcaneostop is one of the procedures that has gained popularity recently. This study aimed to evaluate the outcome of the calcaneostop procedure using screws. Methods: We retrospectively evaluated 57 feet in 44 consecutive patients with FFF undergoing calcaneostop surgery. The same pediatric orthopedic surgeon performed all surgeries. Following a 10-mm incision on the sinus tarsi, a partial thread 6.5 cancellous screw size 40 was inserted. Achilles tendon lengthening was performed on all patients, and a short leg cast was applied. Pain relief, complications, and the change in the talocalcaneal (Kite), talometatarsal (Meary's), and calcaneal inclination (Pitch) angles were evaluated on plain radiographs using a paired t test. Results: Pain relief was achieved in 55 (96.5%) cases, and 2 (3.5%) patients experienced pain after surgery. Other complications, including nerve damage, infection, screw loosening, fracture, or position loss, were not observed. The mean preoperative and postoperative Meary's, Kite, and Pitch angles were 15.74 ± 2.02 (12.30-21.60), 8.72 ± 1.03 (7.20-10.60), 31.23 ± 1.97 (27.80-37.30), 21.30 ± 1.98 (18.50-24.60), 12.40 ± 1.64 (8.50-16.60), and 18.52 ± 1.97 (15.90-22.60), respectively. A significant improvement was observed in each angle following surgery (p<0.001). Conclusion: Calcaneostop is an inexpensive and simple procedure that avoids the involvement of several joints and uses a simple incision leaving a small scar. This procedure is remarkably successful and can be quite convenient.

Risk Communication in Early Containment of COVID-19 Pandemic in Iran: Implementation of the World Health Organization Strategic Preparedness and Response Plan (WHO-SPRP).

Background: Health systems must have functional and efficient preparedness and response plans to manage pandemics. Moreover, it is essential to adjust to changing circumstances and the dynamic character of pandemics. The World Health Organization (WHO) introduced the Strategic Preparedness and Response Plan (SPRP), emphasizing 144 measures across 10 pillars, helping governments prepare and respond to the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to determine how the Iranian health system, based on the WHO-SPRP, addresses strategic preparedness and response plan in the COVID-19 pandemic at the national level. Methods: The WHO-SPRP was adopted and translated into Persian by 2 bilingual natives. The chief of the health office requested that authorized officers complete the SPRP. Then, a meeting was held by officers of related units involved in COVID-19 management to address the SPRP at regional and national levels. Results: Our findings suggest that up to August 2020, effective risk communication and community engagement were not fully established. Our response plan lacked evidence-based information and educational messaging to consistently shape public opinion and impression of a respiratory pandemic. Conclusion: The Iranian health care system and services were almost able to address the SPRP and perform the major indicators that the WHO had proposed. However, special attention should be paid to risk communication and community engagement to empower informed decision-making by individuals and communities.

MicroRNAs signatures, bioinformatics analysis of miRNAs, miRNA mimics and antagonists, and miRNA therapeutics in osteosarcoma.

MicroRNAs (miRNAs) involved in key signaling pathways and aggressive phenotypes of osteosarcoma (OS) was discussed, including PI3K/AKT/MTOR, MTOR AND RAF-1 signaling, tumor suppressor P53- linked miRNAs, NOTCH- related miRNAs, miRNA -15/16 cluster, apoptosis related miRNAs, invasion-metastasis-related miRNAs, and 14Q32-associated miRNAs cluster. Herrin, we discussed insights into the targeted therapies including miRNAs (i.e., tumor-suppressive miRNAs and oncomiRNAs). Using bioinformatics tools, the interaction network of all OS-associated miRNAs and their targets was also depicted.

One-Bone Tarsus: A Case Report.

Tarsal coalition is a condition characterized by abnormal connections between ≥2 tarsi. Although tarsal coalition is not rare, tarsal coalitions involving >2 tarsi are very unusual. In this report, we describe a case of multiple tarsal coalitions in a 24-year-old male who experienced progressively worsening pain for 3 to 4 months before presenting for care. This case was unique in that all the tarsal and tarsometatarsal bones in the foot were fused and formed 1 integrated tarsal. All of the metatarsals were fused as well, and the patient had no joints or ranges of motion in the hindfoot or midfoot. The patient's pain was responsive to anti-inflammatory medications, and no surgical intervention was necessary. To the best of our knowledge, this is the most extensive case of multiple tarsal coalitions described in the literature to date.

Novel molecular insights and new therapeutic strategies in osteosarcoma.

Osteosarcoma (OS) is one of the most prevalent malignant cancers with lower survival and poor overall prognosis mainly in children and adolescents. Identifying the molecular mechanisms and OS stem cells (OSCs) as new concepts involved in disease pathogenesis and progression may potentially lead to new therapeutic targets. Therefore, therapeutic targeting of OSCs can be one of the most important and effective strategies for the treatment of OS. This review describes the new molecular targets of OS as well as novel therapeutic approaches in the design of future investigations and treatment.

Comparing the Intramedullary Nailing Method Versus Dynamic Hip Screw in Treatment of Unstable Intertrochanteric Fractures.

INTRODUCTION: Dynamic Hip Screw fixation is currently considered as a standard treatment for pre-trochanteric fractures; however, due to the long-term hospitalization and some other complications, some researchers have proposed intramedullary nailing as the alternative surgical treatment. The aim of this study was to compare and examine the consequences of the using intramedullary nailing method versus Dynamic Hip Screw. METHODS: In this study 114 patients with unstable Intertrochanteric fracture refer to Rasoul Akram hospital during 2011 to 2013 has been selected. After reduction, fixation surgery with PFN nail (60 patients) and Dynamic Hip Screw (54 patients) has been performed. All patients were screen during surgery and six months after surgery and some parameters like, bleeding, union, as well as complications such as collapse, varus and medialization of the distal fragment were record and patients. RESULTS: About some parameters like cutting length, surgery duration, bleeding there were significant differences between two groups. In six months follow up period 2 patinas from nail and 8 patients from DHS group had non-union. Also from the point of radiologic and clinical parameters, like anterior thigh pain, cut out, medialization of the distal fragment, collapse of the neck, walking recovery and daily activities were significant between two groups. CONCLUSION: Due to the reduced hospital stay in intramedullary nailing method and the necessity of doing repeated surgery and applying intramedullary nailing when the patients are not treated with external fixation, the researchers recommend intramedullary nailing as the first option in treating such patients.

Short-term Outcomes of Induced Membrane Technique in Treatment of Long Bone Defects in Iran.

INTRODUCTION: Severe defects in long bones can be caused by several factors such as trauma that lead to open wound and secondary infections after surgery. Induced membrane technique is one of the therapeutic strategies that can be used for these patients. Due to importance of this method and lack of information about this technique in Iran. AIM: this study was performed to investigate technical strengths and weakness of induced membrane technique. MATERIAL AND METHODS: This case series study conducted on 21 patients with bone defects in the femur and tibia and metatarsal bones referred to orthopedic clinic of Rasoul Akram Hospital, Tehran, Iran, for induced membrane surgery in 2012-2015. Demographic and clinical data were obtained using history, clinical examinations and observations for each patient. Union achievement was the main outcome of this study, which was confirmed by radiographic findings and physical examination. Obtained data was analyzed by SPSS ver. 16. RESULTS: All patients were male except one and their mean age was 30.52 years old. Bone defects were in tibia, femur and metatarsus in 9, 9 and 3 patients, respectively. Three patients received soft tissue reconstruction with flap before induced membrane surgery. Age, defects size, cigarette addiction and drug use and delay to start the treatment had no significant effect on union status. In total, 90% of patients had successful surgery. CONCLUSION: using induced membrane technique in patients with defects in their long bone such as tibia, femur and metatarsus would lead to high success for reconstruction.

Evaluation of Patellar Position before and After Medial Opening Wedge High Tibial Osteotomy: Radiographic and Computed Tomography Findings.

INTRODUCTION: Genovarum is a common orthopedic problem. Its optimal prompt treatment is an issue of importance. AIM: This study was conducted to determine the radiographic changes in patella bone before and after open wedge high tibial osteotomy. MATERIAL AND METHODS: In this quasi-experimental study, 43 patients were enrolled and underwent open wedge high tibial osteotomy and the radiographic and CT-scan indices including Q-Angle, Congruence Angle, Insall-Salvati index, and TTTG were measured and compared before and after surgery. RESULTS: The result revealed that all indices including Q-Angle, Congruence Angle, Insull-Salvati index, and TTTG were not significantly differed across the study (P > 0.05). There was no difference between DLFA values before and after the operation (P> 0.05), while MPTA values were significantly different before and after operation (p <0.001). CONCLUSIONS: Totally it may be concluded that imaging indices are not differed after open wedge high tibial osteotomy and monitoring for them is not necessary and they would have no prognostic role.

Evaluation of the Etiologies of Implant Fracture in Patients With Fractures of the Implants of Lower Limbs' Long Bones.

BACKGROUND: Orthopedics implants are important tools for treatment of bone fractures. Despite available recommendations for designing and making the implants, there are multiple cases of fracture of these implants in the body. Hence, in this study the frequency of failure of implants in long bones of lower extremities was evaluated. METHODS AND MATERIALS: In this cross-sectional study, two types of fractured implants in the body were analyzed and underwent metalogical, mechanical, and modeling and stress-bending analysis. RESULTS: The results revealed that the main cause of fractures was decreased mechanical resistance due to inappropriate chemical composition (especially decreased percentages of Nickel and Molybdenum). CONCLUSIONS: It may be concluded that following the standard chemical composition and use of optimal making method are the most important works for prevention of failure of implants.

Computed Tomographic measurement of distal femor rotation in Iranian population.

BACKGROUND: Proper rotation of components in total knee arthroplasty (TKA) will largely affect the postoperative outcome. Ethnical variation may affect rotational profile. We aimed to evaluate distal femur rotation in Iranian population using transepicondylar axes. METHODS: From a total of 450 knee CT scans and via consecutive sampling, 150 qualified subjects with normal lower extremities alignment were selected comprising 96 (64%) males and 54 (36%) females aging 17-80 years. The posterior condylar angle and condylar twist angles were defined as angles between either surgical epicondylar axis (line connecting lateral epicondylar prominence and the medial sulcus) or clinical epicondylar axis (line connecting most prominent points of both epicondyle) and posterior conylar line. Data were compared among genders. RESULTS: Average age of our samples was 43 years (ranging 11-80). Mean (±sd) values for posterior condylar angle and condylar twist angles were 2.35º (±1.34) and 5.77º (±1.70), respectively. The former variable was not discernible in twenty of our subjects because of obscure medial sulcus. Our findings were totally appeared similar to studies from other ethnicities and the observed minor differences may have originated from amount of osteoarthritis and malalignment. CONCLUSION: Overall, Iranian distal femur rotational profile was similar to other reports. Some minor observed differences may be partially due to samples' age and different amount of knee osteoarthritis. It is proposed to rely on several methods for determining rotational profile while performing TKA. Moreover, preoperative computed tomography should be fully scrutinized especially in severely osteoarthitic knees.

Morphology of proximal tibia in Iranian population and its correlation with available prostheses.

BACKGROUND: Total knee arthroplasty is a complex procedure aiming to relieve pain and improve function. It is critical to select prosthesis that best cover the bone surfaces. Ethnicity may affect fitness of the components mainly designed for Caucasian populations. This study aimed to evaluate morphometric features of proximal tibia in Iranian population. METHODS: During 2013, 150 consecutive patients (96 males and 54 females) form orthopedics department of Rasoul-Akram hospital with knee CT scan were randomly enrolled. We entered cases with apparent normal extremity alignment and bone maturity. Cases with history of fracture or conditions affecting knee profile were excluded. Standard cuts were simulated on CT scan. Anteroposterior (AP), mediolateral (ML) and aspect ratio (ML/AP) were measured for general morphology. Medial and lateral AP distance of tibia and their distance to tibial center were measured for checking symmetry. RESULTS: Mean age was 43.0± 10.4 years (rang 11-80). Males showed significantly larger values in ML dimension and aspect ratio than females under a given AP value (p<0.001). However, the aspect ratio was suggestive of similar configuration of proximal tibia profiles among genders. Totally, close correlations were observed among simulated cuts and size-matched tibial components of the prostheses. However, better coverage was provided by some brands via designing interchangeable components for a given dimension. Medial and lateral condyles of tibia were almost symmetrical. CONCLUSION: Our findings indicated that some alterations in the shape of the components are needed to provide optimal coverage in Iranian population. We propose symmetrical configuration in designing tibial components as well.

Designing and synthesis of injectable hydrogel based on carboxymethyl cellulose/carboxymethyl chitosan containing QK peptide for femoral head osteonecrosis healing.

Femoral head necrosis is a debilitating disorder that typically caused by impaired blood supply to the hip joint. In this study, a novel injectable hydrogel based on Oxidized Carboxymethyl Cellulose (OCMC)-Carboxymethyl Chitosan (CMCS) polymers containing an angiogenesis stimulator peptide (QK) with a non-toxic crosslinking interaction (Schiff based reaction) was synthesized to enhance angiogenesis following femoral head necrosis in an animal model. The physicochemical features of fabricated injectable hydrogel were analyzed by FTIR, swelling and degradation rate, rheometry, and peptide release. Also, the safety and efficacy were evaluated following an in vitro hydrogel injection study and an avascular necrosis (AVN) animal model. According to the results, the hydrogel exhibited an appropriate swelling ratio and water uptake (>90 %, 24 h) as well as a suitable degradation rate over 21 days accompanied by a continuous peptide release. Also, data showed that hydrogels containing QK peptide boosted the proliferation, differentiation, angiogenesis, and osteogenic potential of both Bone Marrow mesenchymal Stem Cells (BM-MSCs) and human umbilical vein endothelial cells (HUVECs) (****p < 0.0001 and ***p < 0.001, respectively). Furthermore, molecular and histological evaluations significantly demonstrated the overexpression of Runx2, Osteocalcin, Collagen I, VEGF and CD34 genes (**p < 0.01 and ***p < 0.001, respectively), and also femoral head necrosis was effectively prohibited, and more blood vessels were detected in defect area by OCMC-CMCS hydrogel containing QK peptide (bone trabeculae >9000, ***p < 0.001). In conclusion, the findings demonstrate that OCMC-CMCS-QK injectable hydrogel could be considered as an impressive therapeutic construct for femoral head AVN healing.

Skeletal muscle post-conditioning by diazoxide, anti-oxidative and anti-apoptotic mechanisms.

Pretreatment with diazoxide, K(ATP) channel opener, increases tissue tolerance against ischemia reperfusion (IR) injury. In clinical settings pretreatment is rarely an option therefore we evaluated the effect of post-ischemic treatment with diazoxide on skeletal muscle IR injury. Rats were treated with either saline, diazoxide (K(ATP) opener; 40 mg/kg) or 5-hydroxydecanoate (5-HD; mitochondrial K(ATP) inhibitor; 40 mg/kg) after skeletal muscle ischemia (3 h) and reperfusion (6, 24 or 48 h). Tissue contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activities, Bax and Bcl-2 protein expression and muscle histology were determined. Apoptosis was examined (24 and 48 h) after ischemia. IR induced severe histological damage, increased MDA content and Bax expression (24 and 48 h; p < 0.01) and decreased CAT and SOD activities (6 and 24 h, p < 0.01 and 48 h, p < 0.05), with no significant effect on Bcl-2 expression. Diazoxide reversed IR effects on MDA (6 and 24 h; p < 0.05), SOD (6 and 24 h; p < 0.01) and CAT (6 and 48 h, p < 0.05 and 24 h p < 0.01) and tissue damage. Diazoxide also decreased Bax (24 and 48 h; p < 0.05) and increased Bcl-2 protein expression (24 and 48 h; p < 0.01). Post-ischemic treatment with 5-HD had no significant effect on IR injury. Number of apoptotic nuclei in IR and 5-HD treated groups significantly increased (p < 0.001) while diazoxide decreased apoptosis (p < 0.01). The results suggested that post-ischemic treatment with diazoxide decrease oxidative stress in acute phase which modulates expression of apoptotic proteins in the late phase of reperfusion injury. Involvement of KATP channels in this effect require further evaluations.