Muscle wasting, known to develop in patients with chronic kidney disease (CKD), is a deleterious consequence of numerous complications associated with deteriorated renal function. Muscle wasting in CKD mainly involves dysregulated muscle protein metabolism and impaired muscle cell regeneration. In this narrative review, we discuss the cardinal role of the insulin-like growth factor 1 and myostatin signaling pathways, which have been extensively investigated using animal and human studies, as well as the emerging concepts in microRNA- and gut microbiota-mediated regulation of muscle mass and myogenesis. To ameliorate muscle loss, therapeutic strategies, including nutritional support, exercise programs, pharmacological interventions, and physical modalities, are being increasingly developed based on advances in understanding its underlying pathophysiology.

Background: Partial-thickness rotator cuff tears (PTRCTs) is not uncommon, and various nonsurgical injection therapy for PTRCTs emerged. Platelet-rich plasma (PRP) and hyaluronic acid (HA) injection were proposed for treating PTRCTs; however, the relation of dose among injectates was still lacking. Methods: This was a prospective, nonrandomized, comparative study. The aim of the study was to compare the effects of ultrasound-guided single PRP injection with three doses of HA injection, combination of postinjection rehabilitation, for treating PTRCTs. Subjects received either ultrasound-guided PRP injection and rehabilitation exercise, or ultrasound-guided subacromial HA injection and rehabilitation exercise. Shoulder Pain and Disability Index (SPADI), range of motion (ROM), pain visual analog scale (VAS), and Constant-Murley Shoulder Score (CMSS) were recorded before injection, and at 1 and 3 months after injection. Results: Forty-eight patients were enrolled. They received either ultrasound-guided single PRP (n = 24) intralesional and peritendinous injection or three doses of HA (n = 24) subacromial injection plus rehabilitation exercise. In the PRP group, SPADI scores, VAS scores, CMSS significantly improved at 1-month and 3-month follow up; flexion and abduction ROM significantly increased at 3-month follow up. In the HA group, SPADI scores, VAS during overhead activities, VAS night pain, and CMSS significantly improved in the first and third months; flexion and active abduction ROM significantly increased in the third month. The PRP group revealed significantly better passive abduction ROM and CMSS at third month than HA group. Conclusion: Ultrasound-guided single PRP injection exhibited comparable benefit to three doses of HA injection in patients with PTRCTs short-termly, with an extended effect regarding passive shoulder abduction ROM and CMSS.