Alessandra Menon

Regenerative Medicine in Rotator Cuff Injuries

Rotator cuff injuries are a common source of shoulder pathology and result in an important decrease in quality of patient life. Given the frequency of these injuries, as well as the relatively poor result of surgical intervention, it is not surprising that new and innovative strategies like tissue engineering have become more appealing. Tissue-engineering strategies involve the use of cells and/or bioactive factors to promote tendon regeneration via natural processes. The ability of numerous growth factors to affect tendon healing has been extensively analyzed in vitro and in animal models, showing promising results. Platelet-rich plasma (PRP) is a whole blood fraction which contains several growth factors. Controlled clinical studies using different autologous PRP formulations have provided controversial results. However, favourable structural healing rates have been observed for surgical repair of small and medium rotator cuff tears. Cell-based approaches have also been suggested to enhance tendon healing. Bone marrow is a well known source of mesenchymal stem cells (MSCs). Recently, ex vivo human studies have isolated and cultured distinct populations of MSCs from rotator cuff tendons, long head of the biceps tendon, subacromial bursa, and glenohumeral synovia. Stem cells therapies represent a novel frontier in the management of rotator cuff disease that required further basic and clinical research.

Lipogems Product Treatment Increases the Proliferation Rate of Human Tendon Stem Cells without Affecting Their Stemness and Differentiation Capability

Increasing the success rate of rotator cuff healing remains tremendous challenge. Among many approaches, the possibility of activating resident stem cells in situ, without the need to isolate them from biopsies, could represent valuable therapeutic strategy. Along this line, it has been recently demonstrated that lipoaspirate product, Lipogems, contains and produces growth-factors that may activate resident stem cells. In this study, human tendon stem cells (hTSCs) from the rotator cuff were cocultured in a transwell system with the Lipogems lipoaspirate product and compared to control untreated cells in terms of cell proliferation, morphology, stem cell marker and VEGF expression, and differentiation and migration capabilities. Results showed that the Lipogems product significantly increases the proliferation rate of hTSCs without altering their stemness and differentiation capability. Moreover, treated cells increase the expression of VEGF, which is crucial for the neovascularization of the tissue during the healing process. Overall, this study supports that directly activating hTSCs with the Lipogems lipoaspirate could represent a new practical therapeutic approach. In fact, obtaining a lipoaspirate is easier, safer, and more cost-effective than harvesting cells from tendon or bone marrow biopsies, expanding them in GMP facility and then reinjecting them in the patient.

Advantages of Arthroscopic Rotator Cuff Repair With a Transosseous Suture Technique: A Prospective Randomized Controlled Trial

Background: Rotator cuff tear is a common finding in patients with painful, poorly functioning shoulders. The surgical management of this disorder has improved greatly and can now be fully arthroscopic. Purpose: To evaluate clinical and radiological results of arthroscopic rotator cuff repair using 2 different techniques: single-row anchor fixation versus transosseous hardware-free suture repair. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Sixty-nine patients with rotator cuff tears were enrolled: 35 patients were operated with metal anchors and 34 with standardized transosseous repair. The patients were clinically evaluated before surgery, during the 28 days after surgery, and at least 1 year after the operation by the use of validated rating scores (Constant score, QuickDASH, and numerical rating scale [NRS]). Final follow-up was obtained at more than 3 years by a QuickDASH evaluation to detect any difference from the previous follow-up. During the follow-up, rotator cuff integrity was determined through magnetic resonance imaging and was classified according to the 5 Sugaya categories. Results: Patients operated with the transosseous technique had significantly less pain, especially from the 15th postoperative day: In the third week, the mean NRS value for the anchor group was 3.00 while that for transosseous group was 2.46 (P = .02); in the fourth week, the values were 2.44 and 1.76, respectively (P < .01). No differences in functional outcome were noted between the 2 groups at the final evaluation. In the evaluation of rotator cuff repair integrity, based on Sugaya magnetic resonance imaging classification, no significant difference was found between the 2 techniques in terms of retear rate (P = .81). Conclusion: No significant differences were found between the 2 arthroscopic repair techniques in terms of functional and radiological results. However, postoperative pain decreased more quickly after the transosseous procedure, which therefore emerges as a possible improvement in the surgical repair of the rotator cuff. Registration: NCT01815177 (ClinicalTrials.gov identifier).

Effects of the pulsed electromagnetic field PST® on human tendon stem cells: A controlled laboratory study

BackgroundCurrent clinical procedures for rotator cuff tears need to be improved, as a high rate of failure is still observed. Therefore, new approaches have been attempted to stimulate self-regeneration, including biophysical stimulation modalities, such as low-frequency pulsed electromagnetic fields, which are alternative and non-invasive methods that seem to produce satisfying therapeutic effects. While little is known about their mechanism of action, it has been speculated that they may act on resident stem cells. Thus, the purpose of this study was to evaluate the effects of a pulsed electromagnetic field (PST®) on human tendon stem cells (hTSCs) in order to elucidate the possible mechanism of the observed therapeutic effects.MethodshTSCs from the rotator cuff were isolated from tendon biopsies and cultured in vitro. Then, cells were exposed to a 1-h PST® treatment and compared to control untreated cells in terms of cell morphology, proliferation, viability, migration, and stem cell marker expression.ResultsExposure of hTSCs to PST® did not cause any significant changes in proliferation, viability, migration, and morphology. Instead, while stem cell marker expression significantly decreased in control cells during cell culturing, PST®-treated cells did not have a significant reduction of the same markers.ConclusionsWhile PST® did not have significant effects on hTSCs proliferation, the treatment had beneficial effects on stem cell marker expression, as treated cells maintained a higher expression of these markers during culturing. These results support the notion that PST® treatment may increase the patient stem cell regenerative potential.

Distance of the Posterior Interosseous Nerve from the Radial Head during Elbow Arthroscopy: An Anatomical Study

Purpose  The aims of this study were to measure the distance of the posterior interosseous nerve (PIN) from the radial head (RH) and its variations with forearm movements. Methods  Five fresh frozen cadaver specimens were dissected under arthroscopy. An anterior capsulectomy extended to the entire lateral compartment was performed. The need of soft tissue dissection to isolate the nerve in the extracapsular space was recorded. The distance between the nerve and the anterior part of the RH was then measured with a graduated caliper inserted via the midlateral portal with the forearm in neutral position, full pronation, and full supination. Results  The PIN was identifiable in all the specimens. In four cases, it was surrounded by a thick layer of adipose tissue, and further dissection was necessary to isolate it. Damage of the PIN during dissection occurred in one case, in which the proximal part of the nerve was accidentally cut. In three of the remaining cases, an increased distance was measured with the forearm in supination, as compared with neutral and full pronation position. Conclusion  This anatomical study suggests that in most of the cases, the PIN does not lay just extracapular at the level of the radiocapitellar joint, but is surrounded by a thick layer of adipose tissue. Furthermore, its distance from the RH appears to increase with forearm supination. This position could increase the safe working space between RH and PIN. Clinical Relevance  Knowledge of PIN position in relation to the anterior elbow capsule and its changes with forearm movements can help reduce the iatrogenic injuries during elbow arthroscopy.

3D-spheroids: What can they tell us about pancreatic ductal adenocarcinoma cell phenotype?

&NA; We aimed at analyzing the effect of the 3D‐arrangement on the expression of some genes and proteins which play a key role in pancreatic adenocarcinoma (PDAC) progression in HPAF‐II, HPAC and PL45 PDAC cells cultured in either 2D‐monolayers or 3D‐spheroids. Cytokeratins 7, 8, 18, 19 were differently expressed in 3D‐spheroids compared to 2D‐monolayers. Syndecan 1 was upregulated in HPAF‐II and PL45 3D‐spheroids, and downregulated in HPAC. Heparanase mRNA levels were almost unchanged in HPAF‐II, and increased in HPAC and PL45 3D‐spheroids. Hyaluronan synthase (HAS) 2 and 3 mRNA increased in all 3D‐spheroids compared to 2D‐monolayers. CD44 and CD44s were expressed to a lower extent in HPAF‐II and HPAC 3D‐spheroids. By contrast, the CD44s/v3 and the CD44s/v6 ratio increased in HPAC and PL45 3D‐spheroids, compared to 2D‐monolayers. The expression of MMP‐7 was strongly upregulated in 3D‐spheroids. STAT3 was similarly expressed 3D‐spheroids or 2D‐monolayers, while pSTAT3 was almost undetectable in 2D‐monolayers and strongly upregulated in 3D‐spheroids. These results suggest that 3D‐spheroids represent a cell culture model that allows the characterization of PDAC cell phenotype, adding new information that contributes to a better understanding of the biology and behavior of PDAC cells. Highlights3D‐spheroids allow the detection of key characteristics of PDAC cell phenotype.3D‐spheroids contribute to a better understanding of PDAC cell biology.the first study describing the relationship between MMP‐7 and STAT3 in PDAC 3D‐spheroids.

GM1 Ganglioside Promotes Osteogenic Differentiation of Human Tendon Stem Cells

Gangliosides, the sialic acid-conjugated glycosphingolipids present in the lipid rafts, have been recognized as important regulators of cell proliferation, migration, and apoptosis. Due to their peculiar localization in the cell membrane, they modulate the activity of several key cell receptors, and increasing evidence supports their involvement also in stem cell differentiation. In this context, herein we report the role played by the ganglioside GM1 in the osteogenic differentiation of human tendon stem cells (hTSCs). In particular, we found an increase of GM1 levels during osteogenesis that is instrumental for driving the process. In fact, supplementation of the ganglioside in the medium significantly increased the osteogenic differentiation capability of hTSCs. Mechanistically, we found that GM1 supplementation caused a reduction in the phosphorylation of the platelet-derived growth factor receptor-β (PDGFR-β), which is a known inhibitor of osteogenic commitment. These results were further corroborated by the observation that GM1 supplementation was able to revert the inhibitory effects on osteogenesis when the process was inhibited with exogenous PDGF.

Chemical Activation of the Hypoxia-Inducible Factor Reversibly Reduces Tendon Stem Cell Proliferation, Inhibits Their Differentiation, and Maintains Cell Undifferentiation

Adult stem cell-based therapeutic approaches for tissue regeneration have been proposed for several years. However, adult stem cells are usually limited in number and difficult to be expanded in vitro, and they usually tend to quickly lose their potency with passages, as they differentiate and become senescent. Culturing stem cells under reduced oxygen tensions (below 21%) has been proposed as a tool to increase cell proliferation, but many studies reported opposite effects. In particular, cell response to hypoxia seems to be very stem cell type specific. Nonetheless, it is clear that a major role in this process is played by the hypoxia inducible factor (HIF), the master regulator of cell response to oxygen deprivation, which affects cell metabolism and differentiation. Herein, we report that a chemical activation of HIF in human tendon stem cells reduces their proliferation and inhibits their differentiation in a reversible and dose-dependent manner. These results support the notion that hypoxia, by activating HIF, plays a crucial role in preserving stem cells in an undifferentiated state in the “hypoxic niches” present in the tissue in which they reside before migrating in more oxygenated areas to heal a damaged tissue.

Failed Anatomical Shoulder Arthroplasty: Case Example 3

This chapter describes a case of reverse shoulder arthroplasty (RSA) that failed for periprosthetic joint infection associated with instability of the implant. Two-stage revision surgery with another RSA required subsequent revision for recurrent instability treated by polyethylene augmentation to improve stability of the implant. The last procedure was successful and restored function and range of motion allowed the patient to carry out the majority of his daily activities.

Decision-Making in Anterior Shoulder Instability

The choice of operative treatment after shoulder instability depends highly on the risk of recurrent instability. Although Balg et al. has developed the instability severity index score (ISIS) to aid in the surgical decision making, including the factors contributing to a high risk of recurrent dislocation such as younger age (≤ 20 years old), participation in competitive or contact/forced overhead sport, shoulder hyperlaxity and presence of a Hill-Sachs lesion or glenoid bone loss on anteroposterior radiographs, there are still many other factors to be accounted for. The surgical decision making thus proves to be a challenging process with many factors of influence.