Perspectives on the use of gene therapy for chronic joint diseases

Advancements and progress in juvenile idiopathic arthritis: A Review of pathophysiology and treatment

Juvenile idiopathic arthritis (JIA) is a chronic clinical condition characterized by arthritic features in children under the age of 16, with at least 6 weeks of active symptoms. The etiology of JIA remains unknown, and it is associated with prolonged synovial inflammation and structural joint damage influenced by environmental and genetic factors. This review aims to enhance the understanding of JIA by comprehensively analyzing relevant literature. The focus lies on current diagnostic and therapeutic approaches and investigations into the pathoaetiologies using diverse research modalities, including in vivo animal models and large-scale genome-wide studies. We aim to elucidate the multifactorial nature of JIA with a strong focus towards genetic predilection, while proposing potential strategies to improve therapeutic outcomes and enhance diagnostic risk stratification in light of recent advancements. This review underscores the need for further research due to the idiopathic nature of JIA, its heterogeneous phenotype, and the challenges associated with biomarkers and diagnostic criteria. Ultimately, this contribution seeks to advance the knowledge and promote effective management strategies in JIA.

Transdermal drug delivery via microneedles for musculoskeletal systems

As the population is ageing and lifestyle is changing, the prevalence of musculoskeletal (MSK) disorders is gradually increasing with each passing year, posing a serious threat to the health and quality of the public, especially the elderly. However, currently prevalent treatments for MSK disorders, mainly administered orally and by injection, are not targeted to the specific lesion, resulting in low efficacy along with a series of local and systemic adverse effects. Microneedle (MN) patches loaded with micron-sized needle array, combining the advantages of oral administration and local injection, have become a potentially novel strategy for the administration and treatment of MSK diseases. In this review, we briefly introduce the basics of MNs and focus on the main characteristics of the MSK systems and various types of MN-based transdermal drug delivery (TDD) systems. We emphasize the progress and broad applications of MN-based transdermal drug delivery (TDD) for MSK systems, including osteoporosis, nutritional rickets and some other typical types of arthritis and muscular damage, and in closing summarize the future prospects and challenges of MNs application.

Gene Therapy for Osteoarthritis: Pharmacokinetics of Intra-Articular Self-Complementary Adeno-Associated Virus Interleukin-1 Receptor Antagonist Delivery in an Equine Model

Toward the treatment of osteoarthritis (OA), the authors have been investigating self-complementary adeno-associated virus (scAAV) for intra-articular delivery of therapeutic gene products. As OA frequently affects weight-bearing joints, pharmacokinetic studies of scAAV gene delivery were performed in the joints of the equine forelimb to identify parameters relevant to clinical translation in humans. Using interleukin-1 receptor antagonist (IL-1Ra) as a secreted therapeutic reporter, scAAV vector plasmids containing codon-optimized cDNA for equine IL-1Ra (eqIL-1Ra) were generated, which produced eqIL-1Ra at levels 30- to 50-fold higher than the native sequence. The most efficient cDNA was packaged in AAV2.5 capsid, and following characterization in vitro, the virus was injected into the carpal and metacarpophalangeal joints of horses over a 100-fold dose range. A putative ceiling dose of 5 × 10¹² viral genomes was identified that elevated the steady-state eqIL-1Ra in the synovial fluids of injected joints by >40-fold over endogenous levels and was sustained for at least 6 months. No adverse effects were seen, and eqIL-1Ra in serum and urine remained at background levels throughout. Using the 5 × 10¹² viral genome dose of scAAV, and green fluorescent protein as a cytologic marker, the local and systemic distribution of vector and transduced cells following intra-articular injection scAAV.GFP were compared in healthy equine joints and in those with late-stage, naturally occurring OA. In both cases, 99.7% of the vector remained within the injected joint. Strikingly, the pathologies characteristic of OA (synovitis, osteophyte formation, and cartilage erosion) were associated with a substantial increase in transgenic expression relative to tissues in healthy joints. This was most notable in regions of articular cartilage with visible damage, where foci of brilliantly fluorescent chondrocytes were observed. Overall, these data suggest that AAV-mediated gene transfer can provide relatively safe, sustained protein drug delivery to joints of human proportions.

Arthritis gene therapy and its tortuous path into the clinic

Arthritis is a disease of joints. The biology of joints makes them very difficult targets for drug delivery in a manner that is specific and selective. This is especially true for proteinaceous drugs ("biologics"). Gene transfer is the only technology that can solve the delivery problem in a clinically reasonable fashion. There is an abundance of preclinical data confirming that genes can be efficiently transferred to tissues within joints by intra-articular injection using a variety of different vectors in conjunction with ex vivo and in vivo strategies. Using the appropriate gene transfer technologies, long-term, intra-articular expression of anti-arthritic transgenes at therapeutic concentrations can be achieved. Numerous studies confirm that gene therapy is effective in treating experimental models of rheumatoid arthritis (RA) and osteoarthritis (OA) in the laboratory. A limited number of clinical trials have been completed, which confirm safety and feasibility but only 3 protocols have reached phase II; as yet, there is no unambiguous evidence of efficacy in human disease. Only 2 clinical trials are presently underway, both phase II studies using allogeneic chondrocytes expressing transforming growth factor-β1 for the treatment of OA. Phase I studies using adeno-associated virus to deliver interleukin-1Ra in OA and interferon-β in RA are going through the regulatory process. It is to be hoped that the recent successes in treating rare, Mendelian diseases by gene therapy will lead to accelerated development of genetic treatments for common, non-Mendelian diseases, such as arthritis.

Orthopedic gene therapy--lost in translation?

Orthopedic gene therapy has been the topic of considerable research for two decades. The preclinical data are impressive and many orthopedic conditions are well suited to genetic therapies. But there have been few clinical trials and no FDA-approved product exists. This paper examines why this is so. The reasons are multifactorial. Clinical translation is expensive and difficult to fund by traditional academic routes. Because gene therapy is viewed as unsafe and risky, it does not attract major funding from the pharmaceutical industry. Start-up companies are burdened by the complex intellectual property environment and difficulties in dealing with the technology transfer offices of major universities. Successful translation requires close interactions between scientists, clinicians and experts in regulatory and compliance issues. It is difficult to create such a favorable translational environment. Other promising fields of biological therapy have contemplated similar frustrations approximately 20 years after their founding, so there seem to be more general constraints on translation that are difficult to define. Gene therapy has noted some major clinical successes in recent years, and a sense of optimism is returning to the field. We hope that orthopedic applications will benefit collaterally from this upswing and move expeditiously into advanced clinical trials.

Getting arthritis gene therapy into the clinic

Gene transfer technologies enable the controlled, targeted and sustained expression of gene products at precise anatomical locations, such as the joint. In this way, they offer the potential for more-effective, less-expensive treatments of joint diseases with fewer extra-articular adverse effects. A large body of preclinical data confirms the utility of intra-articular gene therapy in animal models of rheumatoid arthritis and osteoarthritis. However, relatively few clinical trials have been conducted, only one of which has completed phase II. This article summarizes the status in 2010 of the clinical development of gene therapy for arthritis, identifies certain constraints to progress and suggests possible solutions.

Gene therapy targeting nuclear factor-kappaB: towards clinical application in inflammatory diseases and cancer

Nuclear factor (NF)-κB is regarded as one of the most important transcription factors and plays an essential role in the transcriptional activation of pro-inflammatory cytokines, cell proliferation and survival. NF-κB can be activated via two distinct NF-κB signal transduction pathways, the so-called canonical and non-canonical pathways, and has been demonstrated to play a key role in a wide range of inflammatory diseases and various types of cancer. Much effort has been put in strategies to inhibit NF-κB activation, for example by the development of pharmacological compounds that selectively inhibit NF-κB activity and therefore would be beneficial for immunotherapy of transplantation, autoimmune and allergic diseases, as well as an adjuvant approach in patients treated with chemotherapy for cancer. Gene therapy targeting NF-κB is a promising new strategy with the potential of long-term effects and has been explored in a wide variety of diseases, ranging from cancer to transplantation medicine and autoimmune diseases. In this review we discuss recent progress made in the development of NF-κB targeted gene therapy and the evolution towards clinical application.