Losartan ameliorates renal fibrosis by inhibiting tumor necrosis factor signal pathway.

Losartan is widely used in the treatment of chronic kidney disease (CKD) and has achieved good clinical efficacy, but its exact mechanism is not clear. We performed high-throughput sequencing (HTS) technology to screen the potential target of losartan in treating CKD. According to the HTS results, we found that the tumor necrosis factor (TNF) signal pathway was enriched. Therefore, we conducted in vivo and in vitro experiments to verify it. We found that TNF signal pathway was activated in both unilateral ureteral obstruction (UUO) rats and human proximal renal tubular epithelial cells (HK-2) treated with transforming growth factor-ß1 (TGF-ß1), while losartan can significantly inhibit TNF signal pathway as well as the expression of fibrosis related genes (such as COL-1, α-SMA and Vimentin). These data suggest that losartan may ameliorate renal fibrosis through modulating the TNF pathway.

MiR-20a-5p facilitates cartilage repair in osteoarthritis via suppressing mitogen-activated protein kinase kinase kinase 2.

Bone marrow mesenchymal stem cell (BMSC) chondrogenic differentiation contributes to the treatment of osteoarthritis (OA). Numerous studies have indicated that microRNAs (miRNAs) regulate the pathogenesis and development of multiple disorders, including OA. Nevertheless, the role of miR-20a-5p in OA remains obscure. Forty male C57BL/6 mice were divided into four groups and were surgically induced OA or underwent sham surgery in the presence or absence of miR-20a-5p. Flow cytometry was implemented to detect surface markers of BMSCs. Reverse transcription quantitative polymerase chain reaction revealed the upregulation of miR-20a-5p during BMSC chondrogenic differentiation. Western blotting displayed that miR-20a-5p inhibition decreased protein levels of cartilage matrix markers but enhanced those of catabolic and hypertrophic chondrocyte markers in BMSCs. Alcian blue staining, hematoxylin­eosin staining and micro-CT revealed that miR-20a-5p inhibition restrained chondrogenic differentiation and miR-20a-5p overexpression promoted the repair of damaged cartilage and subchondral bone, respectively. Luciferase reporter assay identified that mitogen activated protein kinase kinase kinase 2 (Map3k2) was a target of miR-20a-5p in BMSCs. Moreover, the expression of miR-20a-5p and Map3k2 was negatively correlated in murine cartilage tissues. Knocking down Map3k2 could rescue the suppressive influence of miR-20a-5p inhibition on chondrogenic differentiation of BMSCs. In conclusion, miR-20a-5p facilitates BMSC chondrogenic differentiation and contributes to cartilage repair in OA by suppressing Map3k2.

Clinical results of a 10-year follow-up of surgical treatment for elbow stiffness in rheumatoid arthritis: A case series.

BACKGROUND: Rheumatoid arthritis commonly causes transient limitation of joint motion, but the treatment of persistent stiffness in the rheumatoid elbow has rarely been reported. The purpose of this study was to evaluate the long-term clinical results of surgical treatment of rheumatoid elbow stiffness. METHODS: Surgical treatment, including open arthrolysis with hinged external fixation, total synovectomy, and ulnar nerve release and anteriorization, was performed in 48 elbows in 43 patients with rheumatoid arthritis and early joint destruction. Mobility (flexion-extension and pronation-supination), Mayo Elbow Performance Score (MEPS), visual analog scale (VAS) score, muscle strength, nerve symptoms, postoperative complications, and recurrent synovitis were evaluated 9-11 years (average, 9.88 years) postoperatively. RESULTS: The mobility of the elbow was significantly improved over the preoperative period either in extension, flexion, protonation, supination (P < .001, P < .001, P < .001, P = .002). The mean MEPS was significantly improved from 56.25 points (range, 30-90) to 87.40 points (range, 40-100) (P < .001). The pain was relieved, and the mean VAS score was reduced from 3.56 (range, 0-8) to 1.08 (range, 0-5) points (P < .001). Preoperative ulnar nerve symptoms were observed in 17 patients and relieved in 10 (59%) patients, and the mean Amadio score was raised from 6.9 (range, 3-9) to 7.96 (range, 4-9) points (P < .001). Through surgical treatment and postoperative rehabilitation, the mean grip strength of the patients was significantly improved from an average of 9.01 (range, 3.4-18.5) to 17.56 kg (range, 3.9-40.2) (P < .001). Five elbows developed recurrent synovitis, and one underwent total elbow arthroplasty. Postoperative complications were uncommon and not severe. CONCLUSION: Surgical treatment is a reliable procedure for rheumatoid elbow stiffness and can be effective in improving elbow mobility, function, muscle strength, pain relief, and relief of nerve symptoms.

Structural definition of the discrete hotspot sites of BMP-2 conformational wrist epitope and rational design of the hotspot-derived osteogenic peptides against chondrocyte senescence.

The bone morphogenetic protein-2 (BMP-2) is an essential regulator of bone formation and remodeling, which has also been implicated in the pathogenesis of osteoarthritis and its closely related chondrocyte senescence. The BMP-2 uses a conformational wrist epitope and a linear knuckle epitope to interact with type-I (BMPR-I) and type-II (BMPR-II) receptors, respectively. Previously, the knuckle epitope has been intensely studied, but the wrist epitope still remains largely unexplored due to its discontinuous nature. In the present work, the intermolecular interaction of BMP-2 with BMPR-I was investigated systematically at structural, energetic and dynamic levels. Three discrete hotspots that represent the key BMPR-I recognition sites of BMP-2 were identified; they are spatially dispersed over the two monomers of BMP-2 dimer and totally account for 83.5 % binding potency of BMP-2 to BMPR-I (hotspot 1: residues 49-70 in monomer 1; hotspot 2: residues 24-31 in monomer 2; hotspot 3: residues 88-107 in monomer 2). Therefore, we defined the three discrete hotspot sites as the core region of wrist epitope; their contribution to the binding increases in the order: hotspot 2 < hotspot 3 < hotspot 1. We demonstrated that the primary hotspot 1 site has a native U-shaped conformation in the full-length BMP-2 protein context, but it cannot maintain in the native conformation when split from the context to obtain a free hotspot-1 peptide, thus largely impairing its binding potency to BMPR-I. We further employed disulfide-bonded cyclization and head-to-tail cyclization to constrain the peptide conformation, and found that only the former can effectively constrain the peptide into native conformation, thus considerably improving its binding affinity to BMPR-I, whereas the latter totally disorders the native conformation, thus rendering the peptide as a full nonbinder of BMPR-I.

Synthetic Homogeneous Glycoforms of the SARS-CoV-2 Spike Receptor-Binding Domain Reveals Different Binding Profiles of Monoclonal Antibodies.

SARS-CoV-2 attaches to its host receptor, angiotensin-converting enzyme 2 (ACE2), via the receptor-binding domain (RBD) of the spike protein. The RBD glycoprotein is a critical target for the development of neutralizing antibodies and vaccines against SARS-CoV-2. However, the high heterogeneity of RBD glycoforms may lead to an incomplete neutralization effect and impact the immunogenic integrity of RBD-based vaccines. Investigating the role of different carbohydrate domains is of paramount importance. Unfortunately, there is no viable method for preparing RBD glycoproteins with structurally defined glycans. Herein we describe a highly efficient and scalable strategy for the preparation of six glycosylated RBDs bearing defined structure glycoforms at T323, N331, and N343. A combination of modern oligosaccharide, peptide synthesis and recombinant protein engineering provides a robust route to decipher carbohydrate structure-function relationships.

Machine learning-guided evolution of BMP-2 knuckle Epitope-Derived osteogenic peptides to target BMP receptor II.

Bone morphogenetic protein-2 (BMP-2) is a key regulator of bone formation, growth and regeneration, which contains a conformational wrist epitope and a linear knuckle epitope that are functionally responsible for the protein by mediating its interaction with type-I and type-II receptors, respectively. Previously, a long (19-mer) knuckle peptide derived from the knuckle epitope region (residues 73-92) has been found to promote osteogenesis and bone repair. Here, we attempt to rationally redesign the knuckle peptide by using bioinformatics and machine learning-guided evolution to obtain structurally simplified, potent osteogenic peptides that are capable of targeting type-II receptor. Complex analysis reveals that only a fraction of the epitope region can directly interact with type-II receptor, which represents a small (12-mer) knuckle-derived peptide (KDP0 peptide). Glycine scanning further identifies three KDP0 anchor residues Ser88, Leu90 and Tyr91 that are fundamentally important in the peptide-receptor binding. Systematic mutation, amino acid combination and uniform design of other nine KDP0 non-anchor residues generate 32 new knuckle-derived peptides (KDP1-KDP32); their binding affinities to recombinant protein of human type-II receptor are determined using fluorescence spectroscopy assay. The resulting affinity values (Kd) are used to train six regression models developed by combination of two machine learning methods and three amino acids descriptors. The best SVM/VHSE predictor is then utilised to guide the genetic evolution of a knuckle-derived peptide population. Eight peptides (KDP33-KDP40) with high affinity scores are selected from the improved population, and their osteogenic activities on bone marrow stromal cells are measured using alkaline phosphatase assay. Consequently, six out of the 8 tested peptides exhibit increased activity relative to KDP0 peptide. The KDP34 (DFQTWSFLYVEN) is found as the most potent peptide with APL activities of 195% and 279% at 0.01 and 0.1 µg/ml, respectively, which shares a similar binding mode with the native knuckle epitope and can form diverse nonbonded interactions of hydrogen bond, hydrophobic contact, cation-π/π-π stacking and salt bridge with type-II receptor.

[Treatment of elbow joint stiffness by open release combined with distal radius fixation hinged external fixation].

Objective: To observe the effectiveness of open release combined with distal radius fixation hinged external fixation for the treatment of elbow stiffness. Methods: A total of 77 patients with elbow stiffness caused by trauma were enrolled in this study between October 2014 and October 2015. The patients were divided into control group (39 cases) and observation group (38 cases) by random number table method. The patients in the observation group were treated with elbow joint opening and release combined with distal radial fixation hinged external fixation, while the control group was treated with traditional release. There was no significant difference in gender, age, disease causes, original damage diagnosis, the time from injury to operation, preoperative flexion and extension activity of elbow joint, and preoperative Mayo elbow joint function score between 2 groups ( P>0.05). After operation, the function of elbow joint was evaluated by the flexion and extension activity of the elbow joint and the Mayo elbow joint function evaluation standard. Results: The incisions healed by first intention in 2 groups. In observation group, there were 1 case infection of nail tract, 2 cases ulnar nerve symptoms, 1 case elbow ossification, and 1 case moderate pain in the elbow; while in control group, there were 2 cases of infection of nail tract, 2 cases of ulnar nerve symptoms, and 3 cases moderate pain in the elbow. The patients in 2 groups were followed up 6 weeks to 12 months, with an average of 6 months. The flexion and extension activity of elbow joint and Mayo elbow joint function score at last follow-up were significantly improved when compared with preoperative ones ( P<0.05); at last follow-up, the flexion and extension activity of elbow joint and Mayo elbow joint function score in observation group patients were significantly better than those in control group ( P<0.05). According to the Mayo elbow function evaluation standard, the results were excellent in 27 cases, good in 10 cases, and fair in 1 case, with an excellent and good rate of 97.4% in observation group; and the results were excellent in 12 cases, good in 21 cases, fair in 4 cases, and poor in 2 cases, with an excellent and good rate of 84.6% in control group; showing no significant difference between 2 groups ( P=0.108). Conclusion: Open release combined with distal radius fixation hinged external fixation can significantly improve the elbow function of patients with traumatic elbow stiffness, its recovery of elbow function was superior to the traditional release.

Effect of disease duration on functional outcomes and complications after arthrolysis in patients with elbow stiffness.

HYPOTHESIS: The purpose of this study was to determine the effect of a long duration of elbow stiffness on functional outcomes and complications after arthrolysis. METHODS: Participants included consecutive patients with a long duration of elbow stiffness (≥5 years, n = 23) and control patients matched for age, sex, and initial injury type (n = 46). All patients underwent elbow arthrolysis combined with hinged external fixation between March 2014 and March 2016. At baseline and follow-up, we evaluated elbow motion (flexion, extension, supination, pronation, and range of motion) and patient-reported outcomes, including the Mayo Elbow Performance Score (MEPS) and visual analog scale for pain. Postoperative complications including infection, nerve dysfunction, and instability were recorded. RESULTS: There were no significant differences in preoperative elbow pain, range of motion, or MEPS between groups. Postoperatively, pronation and the MEPS in patients with a long disease duration were inferior to those in control patients (P = .041 and P = .016, respectively). Patients with a long disease duration also had a significantly higher incidence of complications than control patients (P = .002). At final follow-up, 7 patients (30%) in the long disease duration group and 3 patients (7%) in the control group presented with nerve symptoms (P = .022). CONCLUSIONS: A long duration of elbow stiffness may negatively influence functional outcomes and increase the risk of complications after arthrolysis.

Risk factors for development of severe post-traumatic elbow stiffness.

PURPOSE: The purpose of this study was to compare different grades of elbow stiffness and investigate demographic, injury, and treatment factors potentially associated with the development of severe elbow stiffness. METHODS: We performed a retrospective study involving 169 patients with post-traumatic elbow stiffness between June 2014 and June 2016. Patient demographics, injury, and treatment details were reviewed. Patients were classified into three groups according to the elbow motion. Ordinal regression analyses were performed to examine the independent factors. RESULTS: Patients were classified into: mild (49 patients), moderate (59 patients), and severe (61 patients) groups. Patients with severe stiffness had a significantly worse elbow functional performance. Univariate ordinal regression revealed that severe elbow stiffness was associated with high-energy injury (odds ratio [OR] 4.73), olecranon fracture (OR 1.92), fracture-dislocation (OR 2.28), and open fracture (OR 3.24). Multivariate regression showed that higher-energy injuries were associated with severe stiffness (OR 4.45, p = 0.003). CONCLUSIONS: Elbow stiffness after fracture surgery often results in joint stiffness. Severe stiffness often resulted in more significant functional impairment. Our study suggested that high-energy injuries were associated with the development of severe elbow stiffness.

Management of elbow stiffness after postoperative treatment of terrible triad elbow injury: maintaining mobility and stability using a combined protocol.

PURPOSES: The purpose of this study was to evaluate the results of our protocol that include the restoration of mobility using open release combined with external fixation and stability using ligament repair, to determine the optimal timing of surgery, and to investigate whether resection and replacement of the radial head are associated with different outcomes. METHODS: Twenty-six patients with elbow stiffness after operation of terrible triad injury of the elbow were treated with our protocol. We assessed the optimal timing of the operation by comparing outcomes between the early treatment group and the delayed treatment group. The comparison was performed to investigate whether the results differed between resection and replacement of the radial head. Stability of the elbow, range of motion (ROM), Mayo Elbow Performance Score (MEPS), and complications were assessed for each patient. RESULTS: The mean interval from the initial surgery to the index procedure was 13 months, and the mean follow-up period was 29 months. The MEPS increased from a mean of 65 points to 94 points. Twenty-five of 26 patients achieved stability of the elbow, and all patients achieved functional ROM. There were no significant differences between the two subgroups with respect to ROM and stability of the elbow. CONCLUSION: Our protocol can restore mobility and stability. Resection and replacement of the radial head are both feasible using this protocol. Lastly, the timing of the surgery was not very rigorous, and the surgical delay may be insignificant. LEVEL OF EVIDENCE: Level IV; Case Series; Treatment Study.

The influence of body mass index on outcome of open arthrolysis for post-traumatic elbow stiffness.

BACKGROUND: Being overweight has become a serious public health concern in China. Higher body mass index has been proven to be associated with poor outcome after orthopedic surgery. The purpose of this study was to examine the effect of being overweight on functional outcomes and complications after open arthrolysis for post-traumatic elbow stiffness. METHODS: We performed a retrospective study including 122 patients with post-traumatic elbow stiffness undergoing arthrolysis, including 84 in the normal weight group and 38 in the overweight group. Demographic data, surgical data, and data on preoperative and postoperative functional performance and complications were obtained. RESULTS: Demographic data and disease characteristics were comparable between the 2 groups at baseline. All patients showed significant improvement after elbow arthrolysis. Postoperatively, the range of motion and Mayo Elbow Performance Score of the normal weight group were significantly better than those of the overweight group. Sixteen patients developed postoperative complications. No significant differences in complication rates between the 2 groups were found. CONCLUSIONS: Most patients showed satisfactory functional outcomes after arthrolysis. The postoperative functional outcomes of the overweight group were inferior to those of the normal weight group to a certain extent. This study underlines the importance of detailed rehabilitation instructions in patients with higher body mass index.

Results and outcome predictors after open release of complete ankylosis of the elbow caused by heterotopic ossification.

BACKGROUND: Heterotopic ossification (HO) may lead to complete elbow ankylosis, resulting in severe disability. The prognostic factors that may be valuable in guiding treatment of this condition have not yet been evaluated. The goals of this study were to describe the outcomes of open release for ankylosed elbow caused by HO and to analyse factors associated with clinical outcomes. METHOD: This retrospective study assessed 41 patients with ankylosed elbows treated by open release surgery. We report final clinical outcomes and analyses of the association between outcomes and clinical variables. RESULTS: Mean patient age was 36.4 years; follow-up was 36.1 months. Mean arc of motion increased from 0 to 112° post-operatively, mean pronation from 34 to 52°, supination from a mean of 51 to 76°, and Mean Mayo Elbow Performance Score (MEPS) from 42.8 to 84.2. Eight patients experienced recurrence, two of whom underwent a second operation: one for elbow instability and one for revision surgery. Linear regression analysis demonstrated that initial injury type (p = 0.020), articular surface damage (p = 0.001), coma iduringthe initial injury (p = 0.001) and concomitant radial head replacement (p = 0.029) were independent factors affecting the final MEPS. CONCLUSIONS: Satisfactory outcomes were achieved, indicating that open release is effective for ankylosed elbows. Our findings demonstrated that initial injury type, articular surface damage, coma and radial head replacement are outcome predictors affecting final outcomes.

[OPEN ARTHROLYSIS COMBINED WITH INTERNAL FIXATOR REMOVAL FOR POST-TRAUMATIC ELBOW STIFFNESS].

OBJECTIVE: To explore the effectiveness and safety of open arthrolysis combined with internal fixator removal for post-traumatic elbow stiffness. METHODS: A retrospective analysis was made on the data of 80 cases treated by open arthrolysis for elbow stiffness between January 2010 and December 2011. The patients were divided into 2 groups: no internal fixation group (group A, n = 39) and internal fixation group (group B, n = 41) according to whether they underwent internal fixator removal at the same time. No significant difference was found in age, gender, affected side, injury time, elbow rigidity grade, and severity of heterotopic ossification (HO) between 2 groups (P > 0.05) except for original injury type (P < 0.05). The effectiveness was evaluated by the occurrence of complications including ulnar nerve symptoms, HO recurrence and re-fracture, the elbow range of motion (ROM) and the Mayo elbow performance score (MEPS). RESULTS: The mean follow-up duration was 15.7 months (range, 12-18 months) in group A and 16.1 months (range, 12-20 months) in group B. Ulnar nerve symptoms in 5 cases (12.8%) and HO reccurrence in 1 case (2.6%) occurred in group A, while ulnar nerve symptoms in 4 cases (9.8%), HO recurrence 1 case (2.4%), and refracture in 1 case (2.4%) occurred in group B. The incidence of each complication showed no significant difference between 2 groups (P > 0.05). Both the ROM and the MEPS at last follow-up increased significantly when compared with preoperative ones in 2 groups (P < 0.05). Besides, MEPS of group A was significantly higher than that of group B (t = 2.36, P = 0.02), but no significant difference was found in the ROM between 2 groups at last follow-up (t = 0.40, P = 0.69). Based on MEPS, the results were excellent in 16 cases, good in 16 cases, fair in 6 cases, and poor in 1 case in group A with an excellent and good rate of 82.1%; the results were excellent in 10 cases, good in 25 cases, fair in 4 cases, and poor in 2 cases in group B with an excellent and good rate of 85.4%. There was no significant difference in excellent and good rate between 2 groups (χ2 = 0.16, P = 0.69). CONCLUSION: Open elbow arthrolysis combined with internal fixator removal for post-traumatic elbow stiffness is safe and effective. However, measures for prevention of re-fracture should always be taken into consideration.