Retinitis pigmentosa and stem cell therapy.

Retinitis pigmentosa (RP) is a group of genetic disorders characterized by progressive degeneration of photoreceptors and retinal pigment epithelium (RPE) cells. Its main clinical manifestations include night blindness and progressive loss of peripheral vision, making it a prevalent debilitating eye disease that significantly impacts patients' quality of life. RP exhibits significant phenotypic and genetic heterogeneity. For instance, numerous abnormal genes are implicated in RP, resulting in varying clinical presentations, disease progression rates, and pathological characteristics among different patients. Consequently, gene therapy for RP poses challenges due to these complexities. However, stem cells have garnered considerable attention in the field of RPE therapy since both RPE cells and photoreceptors can be derived from stem cells. In recent years, a large number of animal experiments and clinical trials based on stem cell transplantation attempts, especially cord blood mesenchymal stem cell (MSC) transplantation and bone marrow-derived MSC transplantation, have confirmed that stem cell therapy can effectively and safely improve the outer retinal function of the RP-affected eye. However, stem cell therapy also has certain limitations, such as the fact that RP patients may involve multiple types of retinal cytopathia, which brings great challenges to stem cell transplantation therapy, and further research is needed to solve various problems faced by this approach in the clinic. Through comprehensive analysis of the etiology and histopathological changes associated with RP, this study substantiates the efficacy and safety of stem cell therapy based on rigorous animal experimentation and clinical trials, while also highlighting the existing limitations that warrant further investigation.

Polyhydroxyalkanoates: the natural biopolyester for future medical innovations.

Polyhydroxyalkanoates (PHAs) are a family of natural microbial biopolyesters with the same basic chemical structure and diverse side chain groups. Based on their excellent biodegradability, biocompatibility, thermoplastic properties and diversity, PHAs are highly promising medical biomaterials and elements of medical devices for applications in tissue engineering and drug delivery. However, due to the high cost of biotechnological production, most PHAs have yet to be applied in the clinic and have only been studied at laboratory scale. This review focuses on the biosynthesis, diversity, physical properties, biodegradability and biosafety of PHAs. We also discuss optimization strategies for improved microbial production of commercial PHAs via novel synthetic biology tools. Moreover, we also systematically summarize various medical devices based on PHAs and related design approaches for medical applications, including tissue repair and drug delivery. The main degradation product of PHAs, 3-hydroxybutyrate (3HB), is recognized as a new functional molecule for cancer therapy and immune regulation. Although PHAs still account for only a small percentage of medical polymers, up-and-coming novel medical PHA devices will enter the clinical translation stage in the next few years.

Recent advances of medical polyhydroxyalkanoates in musculoskeletal system.

Infection and rejection in musculoskeletal trauma often pose challenges for natural healing, prompting the exploration of biomimetic organ and tissue transplantation as a common alternative solution. Polyhydroxyalkanoates (PHAs) are a large family of biopolyesters synthesised in microorganism, demonstrating excellent biocompatibility and controllable biodegradability for tissue remodelling and drug delivery. With different monomer-combination and polymer-types, multi-mechanical properties of PHAs making them have great application prospects in medical devices with stretching, compression, twist in long time, especially in musculoskeletal tissue engineering. This review systematically summarises the applications of PHAs in multiple tissues repair and drug release, encompassing areas such as bone, cartilage, joint, skin, tendons, ligament, cardiovascular tissue, and nervous tissue. It also discusses challenges encountered in their application, including high production costs, potential cytotoxicity, and uncontrollable particle size distribution. In conclusion, PHAs offer a compelling avenue for musculoskeletal system applications, striking a balance between biocompatibility and mechanical performance. However, addressing challenges in their production and application requires further research to unleash their full potential in tackling the complexities of musculoskeletal regeneration.