Michael B. Geary

Development of antisense oligonucleotide (ASO) technology against Tgf‐β signaling to prevent scarring during flexor tendon repair

Flexor tendons (FT) in the hand provide near frictionless gliding to facilitate hand function. Upon injury and surgical repair, satisfactory healing is hampered by fibrous adhesions between the tendon and synovial sheath. In the present study we used antisense oligonucleotides (ASOs), specifically targeted to components of Tgf‐β signaling, including Tgf‐β1, Smad3 and Ctgf, to test the hypothesis that local delivery of ASOs and suppression of Tgf‐β1 signaling would enhance murine FT healing by suppressing adhesion formation while maintaining strength. ASOs were injected in to the FT repair site at 2, 6 and 12 days post‐surgery. ASO treatment suppressed target gene expression through 21 days. Treatment with Tgf‐β1, Smad3 or Ctgf ASOs resulted in significant improvement in tendon gliding function at 14 and 21 days, relative to control. Consistent with a decrease in adhesions, Col3a1 expression was significantly decreased in Tgf‐β1, Smad3 and Ctgf ASO treated tendons relative to control. Smad3 ASO treatment enhanced the maximum load at failure of healing tendons at 14 days, relative to control. Taken together, these data support the use of ASO treatment to improve FT repair, and suggest that modulation of the Tgf‐β1 signaling pathway can reduce adhesions while maintaining the strength of the repair.

Obesity/Type II diabetes alters macrophage polarization resulting in a fibrotic tendon healing response

Type II Diabetes (T2DM) dramatically impairs the tendon healing response, resulting in decreased collagen organization and mechanics relative to non-diabetic tendons. Despite this burden, there remains a paucity of information regarding the mechanisms that govern impaired healing of diabetic tendons. Mice were placed on either a high fat diet (T2DM) or low fat diet (lean) and underwent flexor tendon transection and repair surgery. Healing was assessed via mechanical testing, histology and changes in gene expression associated with collagen synthesis, matrix remodeling, and macrophage polarization. Obese/diabetic tendons healed with increased scar formation and impaired mechanical properties. Consistent with this, prolonged and excess expression of extracellular matrix (ECM) components were observed in obese/T2DM tendons. Macrophages are involved in both inflammatory and matrix deposition processes during healing. Obese/T2DM tendons healed with increased expression of markers of pro-inflammatory M1 macrophages, and elevated and prolonged expression of M2 macrophages markers that are involved in ECM deposition. Here we demonstrate that tendons from obese/diabetic mice heal with increased scar formation and increased M2 polarization, identifying excess M2 macrophage activity and matrix synthesis as a potential mechanism of the fibrotic healing phenotype observed in T2DM tendons, and as such a potential target to improve tendon healing in T2DM.

Systemic EP4 inhibition increases adhesion formation in a murine model of flexor tendon repair

Flexor tendon injuries are a common clinical problem, and repairs are frequently complicated by post-operative adhesions forming between the tendon and surrounding soft tissue. Prostaglandin E2 and the EP4 receptor have been implicated in this process following tendon injury; thus, we hypothesized that inhibiting EP4 after tendon injury would attenuate adhesion formation. A model of flexor tendon laceration and repair was utilized in C57BL/6J female mice to evaluate the effects of EP4 inhibition on adhesion formation and matrix deposition during flexor tendon repair. Systemic EP4 antagonist or vehicle control was given by intraperitoneal injection during the late proliferative phase of healing, and outcomes were analyzed for range of motion, biomechanics, histology, and genetic changes. Repairs treated with an EP4 antagonist demonstrated significant decreases in range of motion with increased resistance to gliding within the first three weeks after injury, suggesting greater adhesion formation. Histologic analysis of the repair site revealed a more robust granulation zone in the EP4 antagonist treated repairs, with early polarization for type III collagen by picrosirius red staining, findings consistent with functional outcomes. RT-PCR analysis demonstrated accelerated peaks in F4/80 and type III collagen (Col3a1) expression in the antagonist group, along with decreases in type I collagen (Col1a1). Mmp9 expression was significantly increased after discontinuing the antagonist, consistent with its role in mediating adhesion formation. Mmp2, which contributes to repair site remodeling, increases steadily between 10 and 28 days post-repair in the EP4 antagonist group, consistent with the increased matrix and granulation zones requiring remodeling in these repairs. These findings suggest that systemic EP4 antagonism leads to increased adhesion formation and matrix deposition during flexor tendon healing. Counter to our hypothesis that EP4 antagonism would improve the healing phenotype, these results highlight the complex role of EP4 signaling during tendon repair.

Clinico-Microbiological Review of Non-Contact-Lens-Associated Acanthamoeba Keratitis

Abstract Clinical/microbiological records of 194 patients with microbiological/histopathological diagnosis of Acanthamoeba keratitis from 2007-11 without history of contact lens wear were retrospectively studied. Positive results on corneal scraping and culture were analyzed. Patients were divided based on positive first smear report (group 1/2) and time of presentation (group 3/4). Primary and secondary outcome measures were microbiological positivity rate and to find any possible differences at presentation in sub-groups, respectively. Mean age of patients was 38.5 ± 13.7 years, M:F was 1.8:1. Positivity of first smear examination was 82% and was 98% overall in three scrapings. Ten percent potassium hydroxide with calcoflur white was better than Grams stain (87.1 versus 71.1%). Culture was positive in 79.4% cases. Sub-group analysis showed clinically/demographically similar groups 1 and 2 (p > 0.05). Patients who presented within a month of symptoms (group 3) were significantly younger than others (p = 0.012). Microscopic diagnosis of non-contact-lens Acanthamoeba keratitis is reliable.

Rotator Cuff Tears in the Elderly Patients

Rotator cuff tears (RCT) are a common clinical problem in the geriatric population, and debate exists over how to best provide pain relief and restore shoulder function. Treatment options can be broadly divided into nonsurgical and surgical, with the majority of patients initially placed on a trial of conservative therapy. For those with irreparable RCT, low functional demand, or interest in nonoperative management, there are a number of nonsurgical treatments to consider, including rehabilitation and injections of corticosteroids, hyaluronate, and platelet-rich plasma. Surgical treatment is increasingly common, as geriatric patients remain active with high functional demands. Studies in elderly populations have demonstrated satisfactory healing and clinical results following surgical repair. Predictors of poor outcome after repair are large tear size as well as higher stages of fatty infiltration. Decompression is a less invasive surgical option that has been shown to provide short-term pain relief, though the lasting effects may deteriorate over time. A number of factors must be weighed when considering which patients are likely to benefit from surgical intervention.

Shoulder arthritis secondary to rotator cuff tear: A reproducible murine model and histopathologic scoring system.

Untreated rotator cuff tears can progress to a distinct form of shoulder arthritis, and the mechanism of this progression is poorly understood. Biomechanical, molecular and genetic factors may be at play, and a reliable animal model is needed to enable further research. The purpose of this study was to create a reproducible model of posttraumatic shoulder arthritis in the mouse, and to develop a scoring system for this model to enable future research on interventions, the role of various gene products, and the development of therapies to alter the natural course of the disease. Forty‐five mice underwent operative ligation of the rotator cuff tendons and were followed for 45 weeks following surgery, with free cage activity post‐operatively. Mice were sacrificed at various intervals from 2 to 45 weeks post‐injury and histopathologic scoring was developed and tested by blinded reviewers using both quantitative computational analysis of coronal sections of the shoulder joint and semi‐quantitative grading. The scoring system revealed a progressive, time‐dependent set of tissue changes in the shoulder joint with features similar to human cuff tear arthropathy including acetabularization of the acromion and femoralization of the humeral head. This model establishes that osteoarthritis of the shoulder is distinct from osteoarthritis of the knee or hip, with different stages of degeneration and unique histopathologic features. Using the novel grading procedure and quantitative assessments presented here, future research using this model will enable investigators to test established and novel therapies and evaluate the role of inflammatory factors and gene products in shoulder arthritis. This study provides a reproducible mouse model of shoulder arthritis following isolated injury to the rotator cuff which elucidates characteristics of cuff tear arthropathy and provides a scoring system and venue for future research.

A novel iliotibial band and gluteus maximus tenodesis for the treatment of external coxa saltas in a patient with Ehlers–Danlos syndrome

We report a unique surgical treatment for external coxa saltans refractory to previous open and endoscopic management in a patient with Ehlers–Danlos syndrome. After failure of two endoscopic iliotibial band (ITB) lengthenings and one open gluteus maximus (GMax) lengthening, a novel procedure was conducted, which involved release of the GMax insertion and tenodesis of the anterior and posterior portions of the ITB to prevent pathologic translation over the trochanter.

Erythropoietin accelerates functional recovery after moderate sciatic nerve crush injury

Erythropoietin (EPO) has been identified as a neuroregenerative agent. We hypothesize that it may accelerate recovery after crush injury and may vary with crush severity.

Low-Dose and Short-Duration Matrix Metalloproteinase 9 Inhibition Does Not Affect Adhesion Formation during Murine Flexor Tendon Healing.

Background: After flexor tendon injury and repair, adhesion formation is a substantial concern, as it can result in loss of motion and functional disability. Matrix metalloproteinase 9 (Mmp9) is a gelatinase that contributes to degradation of extracellular matrix and is expressed during flexor tendon healing. Mmp9-/- mice have accelerated remodeling of adhesions during flexor tendon healing, relative to wild-type mice. The purpose of this study was to investigate whether Ro 32-3555, an Mmp9 inhibitor, can improve flexor tendon healing by limiting adhesion formation or enhancing remodeling of scar tissue during murine flexor tendon healing. Methods: Flexor digitorum longus laceration and repair was performed in female C57BL/6J mice. Mice were treated with vehicle or the Mmp9 inhibitor Ro 32-3555 for 8 days. Analysis was performed for digit range of motion and gliding function, biomechanics, gene expression, and Mmp9 activity. Results: An Mmp9 activity assay and zymography confirmed suppression of Mmp9 activity in mice treated with Ro 32-3555. There was no significant difference in tendon gliding or range of motion between vehicle and Ro 32-3555–treated mice. There was also no difference in tendon biomechanical properties between the two groups. Conclusion: Local inhibition of Mmp9 gelatinolytic activity at the flexor tendon repair site is insufficient to alter adhesion formation, remodeling of adhesions, or mechanical properties of healing murine flexor tendons.

Loss of Fixation in Distal Radius Fractures

Loss of fixation is one subset of complications that may be encountered after surgical treatment for distal radius fractures. Fixation loss can occur in a number of ways, including radial shortening of the distal fragment, increasing dorsal angulation, and loss of lunate facet fixation, among others. The present chapter investigates the risk factors for the different mechanisms of fixation loss, their associated functional consequences, and the factors to consider in planning the timing and type of further intervention. For some patients, particularly elderly patients with lower demands, some loss of anatomic reduction may be tolerable and benefits of nonoperative management may outweigh the risks of additional surgical intervention.