Biologic Therapy in Chronic Pain Management: a Review of the Clinical Data and Future Investigations

Sacroiliac joint pain: what treatment and when

INTRODUCTION

Spinal and non-spinal pathologies can cause low back pain. Non-spinal sources of low back pain include the sacroiliac joint (SIJ) and the hip. SIJ pain can be treated either conservatively or surgically. Current strategies for managing sacroiliac joint pain are debated, and limited evidence exists.

AREAS COVERED

The present expert opinion updates current evidence on conservative and surgical modalities for SIJ pain.

EXPERT OPINION

Surgical management for SIJ pain is effective. However, it exposes patients to surgery and, therefore, related complications. Conservative management may be implemented in patients with moderate SIJ pain, with less than six months of symptoms, or not eligible for surgery. Several noninvasive modalities are available, mostly centered on intra-articular injections. Corticosteroids, platelet-rich plasma, and stem cells have only midterm lasting effects, at most for nine months. Radiofrequency ablation is another methodology for pain relief. Both continuous and pulsatile radiofrequency ablation are associated with good outcomes. SIJ fusion can be performed using different techniques; however, a clear recommendation on the most appropriate modality for the management of SIJ pain is still debated.

Cartilage Injury Repair by Human Umbilical Cord Wharton's Jelly/Hydrogel Combined with Chondrocyte

Purpose: There is still a lack of effective treatments for cartilage damage. Cartilage tissue engineering could be a promising treatment method. Human umbilical cord Wharton's jelly (HUCWJ) and hydrogels have received wide attention as a scaffold for tissue engineering. They have not been widely used in clinical studies as their effectiveness and safety are still controversial. This study systematically compared the ability of these two biological tissue engineering materials to carry chondrocytes to repair cartilage injury in vivo. Methods: Chondrocytes were cocultured with HUCWJ or hydrogel for in vivo transplantation. The treatments comprised the HUCWJ+cell, hydrogel+cell, and blank groups. A rabbit model with articular cartilage defect in the knee joint area was established. The defective knee cartilage of different rabbit groups was treated for 3 and 6 months. The efficacy of the various treatments on articular cartilage injury was evaluated by immunohistochemistry and biochemical indices. Results: We found that the HUCWJ+cell and hydrogel+cell groups promoted cartilage repair compared with the blank group, which had no repair effect. The treatment efficacy of each group at 6 months was significantly better than that at 3 months. HUCWJ showed accelerated cartilage repair ability than the hydrogel. Conclusion: This study showed that HUCWJ is useful in cartilage tissue engineering to enhance the efficacy of chondrocyte-based cartilage repair, providing new insights for regenerative medicine. Impact statement Human umbilical cord Wharton's jelly (HUCWJ) and hydrogel are the suitable extracellular matrix for cartilage tissue engineering. This study assessed the capacity of HUCWJ- and hydrogel-loaded chondrocytes to repair cartilage injury in vivo. The data demonstrate that both HUCWJ and hydrogel effectively facilitated cartilage repair, and the repair effects of HUCWJ were significantly better compared with hydrogel, therefore providing a potential candidate for clinical practice of cartilage regeneration therapy.

Creating an Optimal In Vivo Environment to Enhance Outcomes Using Cell Therapy to Repair/Regenerate Injured Tissues of the Musculoskeletal System

Following most injuries to a musculoskeletal tissue which function in unique mechanical environments, an inflammatory response occurs to facilitate endogenous repair. This is a process that usually yields functionally inferior scar tissue. In the case of such injuries occurring in adults, the injury environment no longer expresses the anabolic processes that contributed to growth and maturation. An injury can also contribute to the development of a degenerative process, such as osteoarthritis. Over the past several years, researchers have attempted to use cellular therapies to enhance the repair and regeneration of injured tissues, including Platelet-rich Plasma and mesenchymal stem/medicinal signaling cells (MSC) from a variety of tissue sources, either as free MSC or incorporated into tissue engineered constructs, to facilitate regeneration of such damaged tissues. The use of free MSC can sometimes affect pain symptoms associated with conditions such as OA, but regeneration of damaged tissues has been challenging, particularly as some of these tissues have very complex structures. Therefore, implanting MSC or engineered constructs into an inflammatory environment in an adult may compromise the potential of the cells to facilitate regeneration, and neutralizing the inflammatory environment and enhancing the anabolic environment may be required for MSC-based interventions to fulfill their potential. Thus, success may depend on first eliminating negative influences (e.g., inflammation) in an environment, and secondly, implanting optimally cultured MSC or tissue engineered constructs into an anabolic environment to achieve the best outcomes. Furthermore, such interventions should be considered early rather than later on in a disease process, at a time when sufficient endogenous cells remain to serve as a template for repair and regeneration. This review discusses how the interface between inflammation and cell-based regeneration of damaged tissues may be at odds, and outlines approaches to improve outcomes. In addition, other variables that could contribute to the success of cell therapies are discussed. Thus, there may be a need to adopt a Precision Medicine approach to optimize tissue repair and regeneration following injury to these important tissues.

Intradiscal injection for the management of low back pain

Low back pain (LBP) is a common clinical problem and a major cause of physical disability, imposing a prominent socioeconomic burden. Intervertebral disc degeneration (IDD) has been considered the main cause of LBP. The current treatments have limited efficacy because they cannot address the underlying degeneration. With an increased understanding of the complex pathological mechanism of IDD, various medications and biological reagents have been used for intradiscal injection for the treatment of LBP. There is increasing clinical evidence showing the benefits of these therapies on symptomatic relief and their potential for disc repair and regeneration by targeting the disrupted pathways underlying the cause of the disease. A brief overview of the potential and limitations for these therapies are provided in this review, based on the recent and available data from clinical trials and systematic reviews. Finally, future perspectives are discussed.