Master of Science in Biomedical Engineering, Cleveland State University, 2023, Washkewicz College of Engineering

Tendons serve to attach muscles to bones, and are dense structures composed of fibers. Tendon injuries, as well as tendinopathies, in which a tendon is overused or has been degenerated due to sport injuries or age, are a large problem for many adult patients and account for about 30% of musculoskeletal diseases. Around 33 million musculoskeletal injuries have been reported per year in the United States alone, 50% of which involve tendon and ligament injuries. In American healthcare, only the flexor tendon lacerations sustain estimated costs of anywhere between $240.8 to $409.1 million per year. Having a slow metabolism, tendon tissue needs a substantial period to redevelop enough strength after injury. In most of the cases, tendon tissue does not have full functional recovery because of low regeneration capacity and scar tissue formation. Therefore, the healing of tendon injuries is a significant and clinically challenging problem requiring an urgent need to find alternative and cost-effective treatments. To address this problem, a combinatorial approach involving synergetic use of a 3- dimensional (3D) scaffold system with adult mesenchymal stem cells (MSCs) and locally applied electrical stimulation (ES) was used to produce bioactive extracellular vesicles (EVs) as novel therapeutic tools to enhance tendon regeneration. For this purpose, whey protein isolate (WPI)-based 3D scaffolds were developed to provide favorable microenvironment for MSCs attachment and growth. Conductive graphene and biodegradable Polylactic Acid (PLA) based flexible electronic coil was integrated to the 3D WPI scaffold to provide wireless ES of MSCs and modulate EVs secretion. The isolated EVs were characterized and applied to primary tenocyte cells to evaluate the regenerative activity. The results indicated that the isolated EVs, as well as applied ES, promoted the regeneration capacity of tenocyte cells in vitro and promoted the expression of tendon markers. This re (open full item for complete abstract)

Committee: Metin Uz (Committee Chair); Prabaha Sikder (Committee Member); Chandra Kothapalli (Committee Member) Subjects: Biomedical Engineering; Biomedical Research

Master of Science, The Ohio State University, 2022, Comparative and Veterinary Medicine

Intrasynovial tendon injuries are common debilitating conditions characterized by persistent inflammation and tissue degeneration during healing, and are associated with poorer outcomes than extrasynovial tendon injuries. Changes in tendon structure and vascularity following injury facilitate circulating immune cell influx, of which, monocyte-derived macrophages dominate and persist throughout healing. Macrophages are emerging targets for modulating/manipulating tendon healing as they play a fundamental role by initiating and/or resolving inflammation and recruiting fibroblasts via secreted signals for extracellular matrix (ECM) synthesis. Macrophages respond to local stimuli, exhibit pro-inflammatory or anti-inflammatory/regulatory phenotypes, and exert differential effects at the tissue healing site. Therefore, the aim of this research was to investigate macrophage-derived inflammatory and regulatory signals, and subsequently examine their effects on intrasynovial flexor tendon cell bioactivity. Our specific objectives included (1) optimizing peripheral blood monocyte-derived macrophage in vitro differentiation protocols, and subsequently determining their inflammatory and regulatory cytokine secretion, and (2) investigating intrasynovial flexor tenocyte-macrophage interactions in direct (cell-to-cell contact) and transwell (non-contact mediated) in vitro co-culture model systems. Peripheral blood CD14+ monocytes were isolated from 5 horses (IACUC approved) via sequential density gradient centrifugation and magnetic bead-based positive selection. Forelimb intrasynovial deep digital flexor tendons opposing the distal sesamoid bone were harvested from 4 of those horses immediately following euthanasia, collagenase digested to obtain single cell suspensions, and monolayer passaged twice to isolate intrasynovial flexor tenocytes (CD90+105+27-45-). (1) Monocytes were maintained in basal medium (RPMI + 10% FBS + 1% penicillin-streptomycin) and ± 50ng/mL equine GM-CSF (open full item for complete abstract)

Committee: Sushmitha Durgam (Advisor); Teresa Burns (Committee Member); Samantha Evans (Committee Member); Devina Purmessur (Committee Member) Subjects: Biomedical Research; Immunology