Arthritis is the nation's leading cause of disability. Patients with a previous joint injury are at risk for early development of post-traumatic osteoarthritis (PTOA) even with reconstructive surgery. PTOA is seen in younger patients than age-related osteoarthritis and it has a higher incidence in populations that have high physical occupational demands (i.e., military personnel). Currently, PTOA treatment is primarily for pain until joints fail and joint replacement surgery, an expensive treatment associated with a long rehabilitation. The overall goal of my research is to develop a targeted nanomedicine that can halt cartilage degeneration, improve quality of life and reduce the need for joint replacement in patients. The ability to detect early cartilage damage in traumatic injury or degenerative arthritis has been limited, preventing treatment when therapies may be more beneficial. Depletion of proteoglycans/glycoproteins on the surface of the cartilage in these disorders results in unmasking of the underlying type II collagen (CII). This allows CII to serve as an immunologically recognizable target for monoclonal antibody to type II collagen (MabCII). Fluorescent MabCII can be used for diagnosis of cartilage injury or degeneration or MabCII coupled to nanosomes can target encapsulated drugs for localized delivery to the cartilage lesion. Our preliminary evidence shows a similar strategy can target and recruit reparative chondrocytes or mesenchymal stem cells to the damaged site. Thus, MabCII is used in a comprehensive treatment plan for directing reparative cells to lesions of the articular cartilage and meniscal cartilages and monitoring this by an innovative fluorescent arthroscopy. In addition, recruitment and integration of the reparative cells in the cartilage lesions is optimized by reducing matrix metalloproteinases (MMP) production in the joint by intra-articular injection of a pharmacological inhibitor of the activation of the nuclear factor kappa B (NF-KB) pathway encapsulated in MabCII-targeted nanosomes. These procedures are extremely novel and paradigm shifting for the diagnosis and treatment of joint injury and disease. I am using them for: (1) early diagnosis of damaged and degenerative areas of articular surface and meniscal cartilages in the pig knee using a sensitive, MabCII antibody-guided method of fluorescent arthroscopy (FA). Our PTOA model uses surgically-induced injuries to meniscal and articular cartilages in the knee of the domestic pig. The pig knee closely resembles a human joint in size, weight-bearing requirements and cartilage thickness. The damage is visualized through its binding to fluorescent MabCII using fluorescent arthroscopy, a new procedure that we have developed, and confirmed by histopathology. After FA characterization of the injury, (2) reparative cells are targeted to the area of damaged cartilages in the knee with MabCII antibody. We are investigating the therapeutic efficacy of fluorescent, MabCII-targeted chondrocytes or mesenchymal stem cells derived from bone marrow and adipose tissues intra-articularly injected into joints where articular or meniscal cartilages have been surgically damaged monitoring the cellular localization and persistence by FA. Cell to cell recruitment at the cartilage lesion in the knee is facilitated by an innovative system of biotin/avidin ligands on the surface of the reparative cells and multivalent antibody recruitment of cells binding type II collagen. Reparative tissues are analyzed over time by histopathology and gene expression by RT-PCR. We are (3) further optimizing the recruitment and integration of replacement cells in the cartilage lesion by treatment with MabCII-targeted nanosomes loaded with an inhibitor of the activation of the NF-?B pathway to minimize MMP, a known factor in degradation of cartilage matrices. Diminishing MMP production will be a prototypic target for enhancing reparative efforts. The MabCII- targeted nanosomes encapsulating a selective inhibitor of human IKK-2, an activator of the NF-?B pathway, will be used as a local delivery system to reduce MMPs in damaged cartilage lesions prior to treatment with reparative cells enhancing their survival at the degenerative site. !
Post-traumatic osteoarthritis (PTOA) can result from a single or repetitive injury and is a major cause of disability in younger individuals and is of major concern for Veterans who are at increased risk from this condition. The ability to treat this disorder is limited, contributing to the development of disability in affected individuals, with joint replacement the only option. Early detection and treatment of cartilage damage could play a major role in slowing or preventing progression to total joint involvement, sparing pain and expense. We have developed an antibody that recognizes an early marker of PTOA, type II collagen, a protein that becomes exposed in damaged cartilage. We will use this antibody and antibody-targeted nanosomes for early diagnosis of cartilage lesions by fluorescent arthroscopy and for localized delivery of drugs that may be effective, slowing or preventing disease progression. Using a surgical model of cartilage damage in pigs, we will also prove that this antibody can be used to target reparative cells to the damaged area of the cartilage to fill in the defect. !
