ABSTRACT
There are limited treatments currently available for retinal diseases such as age-related macular degeneration (AMD). Cell-based therapy holds great promise in treating these degenerative diseases. Three-dimensional (3D) polymeric scaffolds have gained attention for tissue restoration by mimicking the native extracellular matrix (ECM). The scaffolds can deliver therapeutic agents to the retina, potentially overcoming current treatment limitations and minimizing secondary complications. In the present study, 3D scaffolds made up of alginate and bovine serum albumin (BSA) containing fenofibrate (FNB) were prepared by freeze-drying technique. The incorporation of BSA enhanced the scaffold porosity due to its foamability, and the Maillard reaction increased crosslinking degree between ALG with BSA resulting in a robust scaffold with thicker pore walls with a compression modulus of 13.08 KPa suitable for retinal regeneration. Compared with ALG and ALG-BSA physical mixture scaffolds, ALG-BSA conjugated scaffolds had higher FNB loading capacity, slower release of FNB in the simulated vitreous humour and less swelling in water and buffers, and better cell viability and distribution when tested with ARPE-19 cells. These results suggest that ALG-BSA MR conjugate scaffolds may be a promising option for implantable scaffolds for drug delivery and retinal disease treatment.
ABSTRACT
BACKGROUND: COVID-19 pandemic has overwhelmed healthcare systems and limited access to surgical care. Urolithiasis can lead to emergencies and affect renal function during long-term follow-up. Therefore, timely and appropriate treatment is essential. MAIN TEXT: This is a non-systematic review of the recently published recommendations regarding urolithiasis treatment options during COVID-19. Fourteen publications were the basis of our review. Regarding anesthesia methods, the optimal methods are still unknown. During COVID-19, most of the endo-urologists changed their routine clinical practice and elective surgical treatment approaches. Despite decreasing number of emergency visits and admissions for stone disease, patients tend to have leukocytosis, higher creatinine levels, increased grade 3 and 4 hydronephrosis, and higher incidence of complications compared to non-COVID-19 time. Several alarming indications if present, intervention should be performed within 24 h to prevent irreversible kidney damage, disease progression, or even death. Some endo-urologists prefer definitive stone treatment over temporarily drainage to reduce the number of emergency room visits and hospital admissions, except if infection is present or staged treatment is planned. Several clinical scenarios of non-emergency and non-urgent urinary stones are present; thus, endo-urologists should appropriately weigh patient's risk and surgery benefit to decide to the proper intervention time. If risks outweighed benefits to the patient, postpone the surgery. Renal colic should be managed with medical expulsive therapy and proper pain control with close follow-up just in case it becomes an emergency. Indwelling JJ stent removal or exchange is a matter of debate; some endo-urologists recommend removing, while others recommend postponing. CONCLUSION: Treatment options for urinary stones have markedly changed during COVID-19 pandemic. The optimal anesthesia methods are still unknown. Emergency intervention is a must if any alarming indications exist. Emergency cases tend to have higher incidence of complications compared to non-COVID-19 time. For non-emergency and non-urgent urolithiasis, endo-urologists should make judicious treatment decision to prioritize urolithiasis treatment, and they should weigh benefits and risks before surgery.
