End binding-3 inhibitor activates regenerative program in age-related macular degeneration.

Wet age-related macular degeneration (AMD), characterized by leaky neovessels emanating from the choroid, is a main cause of blindness. As current treatments for wet AMD require regular intravitreal injections of anti-vascular endothelial growth factor (VEGF) biologics, there is a need for the development of less invasive treatments. Here, we designed an allosteric inhibitor of end binding-3 (EB3) protein, termed EBIN, which reduces the effects of environmental stresses on endothelial cells by limiting pathological calcium signaling. Delivery of EBIN via eye drops in mouse and non-human primate (NHP) models of wet AMD prevents both neovascular leakage and choroidal neovascularization. EBIN reverses the epigenetic changes induced by environmental stresses, allowing an activation of a regenerative program within metabolic-active endothelial cells comprising choroidal neovascularization (CNV) lesions. These results suggest the therapeutic potential of EBIN in preventing the degenerative processes underlying wet AMD.

Determination of rotator cuff tear reparability: an ultrasound-based investigation.

Background: The use of ultrasound as a viable diagnostic tool for routine office visit evaluation of rotator cuff integrity is slowly gaining acceptance in orthopedic practice. However, the reliability of accurately assessing rotator cuff tear reparability by ultrasound has limited evidence in the literature. The purpose of this study was to compare preoperative assessment of cuff tear reparability via ultrasound with the arthroscopic determination of reparability at the time of surgery. Methods: We prospectively collected preoperative ultrasound and arthroscopic imaging data on 145 patients (80 or 55% men and average age of 60.7 years) who underwent arthroscopic posterior superior rotator cuff repair. Three independent experienced orthopedic surgeons retrospectively reviewed all ultrasound studies and arthroscopic imaging and determined if the posterior superior rotator cuff tendon edge was able to be viewed via ultrasound and determined with the arthroscopic images if the tear was reparable. Results: On review of the ultrasound and arthroscopic data, if the edge of the rotator cuff tendon was able to be viewed on the coronal ultrasound image, it was most likely reparable with a positive predictive value of 97.6% and a positive likelihood ratio of 5.8. Sensitivity was 84.4%, and specificity was 76.9%. The negative predictive value was 37.5%, and the negative likelihood ratio was 0.17. The interobserver reliability was 0.63, and the observers were unanimous in determining the tendon edge was able to be visualized in 99 of 145 cases (68%). Conclusion: Preoperative ultrasound evaluation of the shoulder for posterior superior rotator cuff tears is a useful tool for assessing rotator cuff integrity and may help predict intraoperative reparability of the tendon. This study demonstrates that if the cuff tear edge is able to be visualized, there is a high probability of successful arthroscopic restoration of the tendon to its native attachment. Conversely, if the tear edge is unable to be visualized, there is a moderate chance of the tear being irreparable. These results help expand the knowledge base of the usefulness of in-office ultrasound performed by the surgeon in predicting the results of surgical intervention for rotator cuff tears.

Single Medial-Row Anchor With Biceps Tenodesis in a Transosseous Double-Row Construct for Massive Rotator Cuff Tear.

Massive rotator cuff tears are a common issue for patients and can be challenging to manage surgically. While the literature has shown that repair construct can affect the outcome of a rotator cuff repair, and the double-row repair is typically favored over the single-row repair for larger rotator cuff tears, the double-row repair also has some shortcomings. These shortcomings are related to the increased technical difficulty of the procedure, as well as increased costs due to the increased number of anchors used. Both of these factors also lead to an increase in the amount of time spent in the operating room as well. This study describes a surgical technique to help mitigate this shortcoming of the double-row repair by using a single medial-row anchor in our double-row construct for repair of a massive rotator cuff tear.

Semitendinosus Allograft Cable Reconstruction Technique for Massive Irreparable Rotator Cuff Tears.

Massive irreparable rotator cuff tears are difficult to treat. Disruption of the rotator cable and joint capsule leads to altered glenohumeral joint mechanics, superior migration of the humeral head, and limited overhead function. A few graft options exist for reconstruction, with limited outcomes data. A newer technique using a hamstring allograft provides benefits compared with other graft reconstruction options. This Technical Note describes a rotator cable reconstruction using a V-shaped hamstring allograft for treatment of a massive, irreparable rotator cuff tear.

Do we really need to order magnetic resonance imaging? Shoulder surgeon ultrasound practice patterns and beliefs.

BACKGROUND: Despite significant benefits, many orthopedic surgeons are hesitant to incorporate diagnostic ultrasound into their practice. This may be because of a lack of comfort, knowledge, and/or training. The purpose of this study was to analyze practice patterns regarding the use of shoulder ultrasound by orthopedic surgeons to diagnose rotator cuff tears. MATERIALS AND METHODS: We conducted a survey of the members of the American Shoulder and Elbow Surgeons (ASES) regarding their use of ultrasound. A systematic review of the literature on the use of ultrasound in the shoulder by orthopedic surgeons was also performed. RESULTS: Of the members of ASES responding to the survey, 55% are using ultrasound for diagnostic purposes in the shoulder. The leading reason for not using ultrasound as the sole imaging modality prior to performing rotator cuff repair was lack of confidence in the ability to determine the reparability of the tear (83%). Our systematic review showed that for an orthopedic surgeon diagnosing a full-thickness rotator cuff tear, the mean sensitivity was 92% and mean specificity was 89%. CONCLUSIONS: Many ASES surgeons are not using ultrasound in the shoulder despite its many potential benefits over magnetic resonance imaging. This is because of a lack of confidence in the ability to quantify fatty infiltration, muscle atrophy, and the level of retraction medial to the acromion. Our systematic review showed that orthopedic surgeons can be accurate in the diagnosis of full-thickness rotator cuff tears. Future research should focus on defining parameters of shoulder ultrasound associated with rotator cuff tendon reparability. Educating surgeons on ultrasound technique, cost, and evidence may be a promising strategy to enhance the value in musculoskeletal care delivery.

Analysis of biological networks in the endothelium with biomimetic microsystem platform.

Here we describe a novel method for studying the protein "interactome" in primary human cells and apply this method to investigate the effect of posttranslational protein modifications (PTMs) on the protein's functions. We created a novel "biomimetic microsystem platform" (Bio-MSP) to isolate the protein complexes in primary cells by covalently attaching purified His-tagged proteins to a solid microscale support. Using this Bio-MSP, we have analyzed the interactomes of unphosphorylated and phosphomimetic end-binding protein-3 (EB3) in endothelial cells. Pathway analysis of these interactomes demonstrated the novel role of EB3 phosphorylation at serine 162 in regulating the protein's function. We showed that phosphorylation "switches" the EB3 biological network to modulate cellular processes such as cell-to-cell adhesion whereas dephosphorylation of this site promotes cell proliferation. This novel technique provides a useful tool to study the role of PTMs or single point mutations in activating distinct signal transduction networks and thereby the biological function of the protein in health and disease.

VE-PTP stabilizes VE-cadherin junctions and the endothelial barrier via a phosphatase-independent mechanism.

Vascular endothelial (VE) protein tyrosine phosphatase (PTP) is an endothelial-specific phosphatase that stabilizes VE-cadherin junctions. Although studies have focused on the role of VE-PTP in dephosphorylating VE-cadherin in the activated endothelium, little is known of VE-PTP's role in the quiescent endothelial monolayer. Here, we used the photoconvertible fluorescent protein VE-cadherin-Dendra2 to monitor VE-cadherin dynamics at adherens junctions (AJs) in confluent endothelial monolayers. We discovered that VE-PTP stabilizes VE-cadherin junctions by reducing the rate of VE-cadherin internalization independently of its phosphatase activity. VE-PTP serves as an adaptor protein that through binding and inhibiting the RhoGEF GEF-H1 modulates RhoA activity and tension across VE-cadherin junctions. Overexpression of the VE-PTP cytosolic domain mutant interacting with GEF-H1 in VE-PTP-depleted endothelial cells reduced GEF-H1 activity and restored VE-cadherin dynamics at AJs. Thus, VE-PTP stabilizes VE-cadherin junctions and restricts endothelial permeability by inhibiting GEF-H1, thereby limiting RhoA signaling at AJs and reducing the VE-cadherin internalization rate.

N-cadherin signaling via Trio assembles adherens junctions to restrict endothelial permeability.

Vascular endothelial (VE)-cadherin forms homotypic adherens junctions (AJs) in the endothelium, whereas N-cadherin forms heterotypic adhesion between endothelial cells and surrounding vascular smooth muscle cells and pericytes. Here we addressed the question whether both cadherin adhesion complexes communicate through intracellular signaling and contribute to the integrity of the endothelial barrier. We demonstrated that deletion of N-cadherin (Cdh2) in either endothelial cells or pericytes increases junctional endothelial permeability in lung and brain secondary to reduced accumulation of VE-cadherin at AJs. N-cadherin functions by increasing the rate of VE-cadherin recruitment to AJs and induces the assembly of VE-cadherin junctions. We identified the dual Rac1/RhoA Rho guanine nucleotide exchange factor (GEF) Trio as a critical component of the N-cadherin adhesion complex, which activates both Rac1 and RhoA signaling pathways at AJs. Trio GEF1-mediated Rac1 activation induces the recruitment of VE-cadherin to AJs, whereas Trio GEF2-mediated RhoA activation increases intracellular tension and reinforces Rac1 activation to promote assembly of VE-cadherin junctions and thereby establish the characteristic restrictive endothelial barrier.

The HCMV Assembly Compartment Is a Dynamic Golgi-Derived MTOC that Controls Nuclear Rotation and Virus Spread.

Human cytomegalovirus (HCMV), a leading cause of congenital birth defects, forms an unusual cytoplasmic virion maturation site termed the "assembly compartment" (AC). Here, we show that the AC also acts as a microtubule-organizing center (MTOC) wherein centrosome activity is suppressed and Golgi-based microtubule (MT) nucleation is enhanced. This involved viral manipulation of discrete functions of MT plus-end-binding (EB) proteins. In particular, EB3, but not EB1 or EB2, was recruited to the AC and was required to nucleate MTs that were rapidly acetylated. EB3-regulated acetylated MTs were necessary for nuclear rotation prior to cell migration, maintenance of AC structure, and optimal virus replication. Independently, a myristoylated peptide that blocked EB3-mediated enrichment of MT regulatory proteins at Golgi regions of the AC also suppressed acetylated MT formation, nuclear rotation, and infection. Thus, HCMV offers new insights into the regulation and functions of Golgi-derived MTs and the therapeutic potential of targeting EB3.

STIM1 Phosphorylation at Y361 Recruits Orai1 to STIM1 Puncta and Induces Ca2+ Entry.

Store-operated Ca2+ entry (SOCE) mediates the increase in intracellular calcium (Ca2+) in endothelial cells (ECs) that regulates several EC functions including tissue-fluid homeostasis. Stromal-interaction molecule 1 (STIM1), upon sensing the depletion of (Ca2+) from the endoplasmic reticulum (ER) store, organizes as puncta that trigger store-operated Ca2+ entry (SOCE) via plasmalemmal Ca2+-selective Orai1 channels. While the STIM1 and Orai1 binding interfaces have been mapped, signaling mechanisms activating STIM1 recruitment of Orai1 and STIM1-Orai1 interaction remains enigmatic. Here, we show that ER Ca2+-store depletion rapidly induces STIM1 phosphorylation at Y361 via proline-rich kinase 2 (Pyk2) in ECs. Surprisingly, the phospho-defective STIM1-Y361F mutant formed puncta but failed to recruit Orai1, thereby preventing. SOCE Furthermore, studies in mouse lungs, expression of phosphodefective STIM1-Y361F mutant in ECs prevented the increase in vascular permeability induced by the thrombin receptor, protease activated receptor 1 (PAR1). Hence, Pyk2-dependent phosphorylation of STIM1 at Y361 is a critical phospho-switch enabling recruitment of Orai1 into STIM1 puncta leading to SOCE. Therefore, Y361 in STIM1 represents a novel target for limiting SOCE-associated vascular leak.

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability.

The monolayer of endothelial cells lining the vessel wall forms a semipermeable barrier (in all tissue except the relatively impermeable blood-brain and inner retinal barriers) that regulates tissue-fluid homeostasis, transport of nutrients, and migration of blood cells across the barrier. Permeability of the endothelial barrier is primarily regulated by a protein complex called adherens junctions. Adherens junctions are not static structures; they are continuously remodeled in response to mechanical and chemical cues in both physiological and pathological settings. Here, we discuss recent insights into the post-translational modifications of junctional proteins and signaling pathways regulating plasticity of adherens junctions and endothelial permeability. We also discuss in the context of what is already known and newly defined signaling pathways that mediate endothelial barrier leakiness (hyperpermeability) that are important in the pathogenesis of cardiovascular and lung diseases and vascular inflammation.

A Survey of the Use of Ultrasound by Upper Extremity Surgeons.

Background: Ultrasound is a versatile imaging modality that can be used by upper extremity surgeons for diagnostic purposes and guided injections. The perceptions of ultrasound for diagnosis and treatment among upper extremity surgeons and its barriers for adoption have not been formally surveyed. The purpose of this study is to determine the current usage of musculoskeletal ultrasound for diagnostic purposes and guided injections by upper extremity surgeons and their reasons for using it or not using it in practice. Methods: A 22-question survey was distributed to the American Society for Surgery of the Hand (ASSH). The survey questions consisted of respondent characteristic questions and questions pertaining to the use of ultrasound. Chi-square analysis was performed to assess for a difference in ultrasound usage across respondent characteristics. Results: Three hundred four (43%) answered that they have an ultrasound machine in their office; Fifty-one percent (362) of the respondents use ultrasound for diagnostic purposes. Fifty-five (8%) of the survey respondents use ultrasound to diagnose carpal tunnel syndrome; 168 (23.5%) respondents reported that they use ultrasound for guided injections. There was a statistically significant difference between access to an ultrasound machine in the office by practice setting and use of ultrasound for diagnostic purposes by practice setting. Conclusions: The use of ultrasound by upper extremity surgeons is split for diagnostic purposes, with fewer surgeons using ultrasound to diagnose carpal tunnel syndrome and guided injections. Ultrasound machine availability and the use of ultrasound for diagnosis appear to be influenced by practice setting.

The Hidden Lesion of the Subscapularis: Arthroscopically Revisited.

The "hidden lesion" refers to a tear of the subscapularis in the presence of an intact biceps pulley or rotator interval. Visualization of these tears during open surgery is difficult, yet even with the advancement of arthroscopy, visualization can still be challenging. Incomplete visualization of the subscapularis could lead to failure to diagnose a tear of the tendon and subsequently hinder results after shoulder surgery. With the advancement of arthroscopy, a technique to identify these hidden lesions is needed to avoid inferior results. We describe an arthroscopic technique to visualize, diagnosis, and repair these tears when clinically indicated. Implementing this technique in the setting of suspected subscapularis tendon injury can provide complete visualization of the tendon insertion.

Arthroscopic "Panorama" View of the Subacromial Space via Deltoid Fascia Release.

Proper visualization is of paramount importance during arthroscopic rotator cuff repair. We propose a technique that significantly improves the visualization of the rotator cuff when viewing from the anterolateral or lateral portals. This "panorama" view is obtained by a release of the deep layer of the deltoid fascia, which in turn increases the space between the humerus and the deltoid muscle. This release increases the volume of the subdeltoid bursa, secondarily increasing the field of view of the subacromial space with the camera viewing from the anterolateral or lateral portals. This technical note describes a new technique useful in obtaining an excellent view of the subacromial space proving very useful in both the diagnosis and treatment of rotator cuff pathology.

Arthroscopic Distal Clavical Resection Using "Vis-à-Vis" Portal.

Arthroscopic distal clavicle resection has become an increasingly popular procedure in orthopaedics, and various techniques have been published. Many of the arthroscopic distal clavicle resection techniques that have been reported require visualization from the lateral portal with an anterior working portal to perform the resection. While these techniques have reported high success rates, there is often difficulty in viewing the entire acromioclavicular joint from the 2 standard arthroscopic portals (lateral and anterior). This is due to the medial edge of the acromion blocking the ability to visualize the most superior and posterior portions of the distal clavicle. We propose a technique for arthroscopic distal clavicle resection using an accessory anterior portal.

A modification to the Walch classification of the glenoid in primary glenohumeral osteoarthritis using three-dimensional imaging.

BACKGROUND: Since Walch and colleagues originally classified glenoid morphology in the setting of glenohumeral osteoarthritis, several authors have reported varying levels of interobserver and intraobserver reliability. We propose several modifications to the Walch classification that we hypothesize will increase interobserver and intraobserver reliability. METHODS: We propose the addition of the B3 and D glenoids and a more precise definition of the A2 glenoid. The B3 glenoid is monoconcave and worn preferentially in its posterior aspect, leading to pathologic retroversion of at least 15° or subluxation of 70%, or both. The D glenoid is defined by glenoid anteversion or anterior humeral head subluxation. The A2 glenoid has a line connecting the anterior and posterior native glenoid rims that transects the humeral head. Using 3-dimensional computed tomography glenoid reconstructions, 3 evaluators used the original Walch classification and the modified Walch classification to classify 129 nonconsecutive glenoids on 4 separate occasions. Reliabilities were assessed by calculating κ coefficients. RESULTS: Interobserver reliabilities improved from an average of 0.391 (indicating fair agreement) using the original classification to an average of 0.703 (substantial agreement) using the modified classification. Intraobserver reliabilities improved from an average of 0.605 (moderate agreement) to an average of 0.882 (nearly perfect agreement). CONCLUSION: When 3-dimensional glenoid reconstructions and the modified Walch classification described herein are used, improved interobserver and intraobserver reliabilities are obtained.

Release of the stiff elbow with mini-open technique.

BACKGROUND: Currently, there are many techniques used in the surgical release of elbow contracture, but no single technique has gained widespread acceptance. The purpose of this study was to report the outcomes of a lateral-column approach combined with a mini-open triceps-splitting technique for elbow contracture release. METHODS: Thirty-six patients with a mean age of 39 years were included in the study. All patients underwent a combined lateral and minimal posterior triceps-splitting open elbow contracture release. Elbow range of motion and visual analog scale pain scores were recorded. The Mayo Elbow Performance Score was used to assess functional outcome. RESULTS: The mean follow-up period was 38 months. Mean pain levels decreased from 7.59 preoperatively to 0.44 postoperatively (P < .05). The total arc of elbow motion increased from 52° preoperatively to 109° postoperatively, with an improvement of 57° (P < .05). The Mayo Elbow Performance Score improved from 44.17 preoperatively to 90.83 postoperatively (P < .05). CONCLUSION: This study shows that a combined lateral and mini-open triceps-splitting approach is a safe and effective alternative technique for the treatment of elbow contractures.

Scapholunate Advanced Collapse: Motion-Sparing Reconstructive Options.

Scapholunate advanced collapse (SLAC) is a predictable pattern of degenerative wrist arthritis that develops as a result of scapholunate dissociation. The purpose of this article is to review outcomes for the various motion-sparing surgical treatments for SLAC wrist.