Ferroptosis is a novel form of programmed cell death, distinguished from apoptosis, autophagy, and programmed necrosis and has received much attention since it was defined in 2012. Ferroptotic cells physiologically exhibit iron metabolism dysregulation, oxidative stress, and lipid peroxidation. Morphologically, they show plasma membrane disruption, cytoplasmic swelling, and mitochondrial condensation. Osteoporosis is taken more and more seriously as the proportion of the aging population continues to increase globally. Interestingly, ferroptosis has been demonstrated to be involved in the development and progression of osteoporosis in many extant studies. The review summarizes iron metabolism, lipid peroxidation, and the different regulatory signals in ferroptosis. Changes in signaling mechanisms within osteoblasts, osteoclasts, and osteocytes after ferroptosis occur are explained here. Studies showed ferroptosis play an important role in different osteoporosis models (diabetes osteoporosis, postmenopausal osteoporosis, glucocorticoid-induced osteoporosis). Inhibitors and EC (Exos) targeting ferroptosis could ameliorate bone loss in osteoporotic mice by protecting cells against lipid peroxidation. Shortly, we hope that more effective and appropriate clinical therapy means will be utilized in the treatment of osteoporosis.

The repair of osteoporotic bone defects remains inadequately addressed, primarily due to a disruption in bone homeostasis, characterized by insufficient bone formation and excessive bone resorption. Current research either focuses on promoting bone formation or inhibiting bone resorption, however, the bone repair efficacy of these single‐target therapeutic strategies is limited. Herein, a “two‐way regulation” bone homeostasis strategy is proposed utilizing piezoelectric composite membranes (DAT/KS), capable of simultaneously regulating osteogenesis and osteoclastogenesis, with high piezoelectric performance, good biocompatibility, and excellent degradability, to promote bone regeneration under osteoporotic conditions. The DAT/KS membrane under ultrasound (US) treatment enables the controlled modulation of piezoelectric stimulation and the release of saikosaponin D (SSD), which promotes osteogenic differentiation while simultaneously inhibiting osteoclast differentiation and function, thereby effectively restoring bone homeostasis and enhancing osteoporotic bone repair. Mechanistic insights reveal the promotion of both canonical and non‐canonical Wnt signaling in bone marrow mesenchymal stem cells (BMSCs), which determines their osteogenic differentiation fate, and the downregulation of the NF‐κB signaling in bone marrow mononuclear macrophages (BMMs). This study presents optimized sono‐piezoelectric biomaterials capable of bidirectionally regulating both osteogenic and osteoclastic differentiation, providing a new potential therapeutic approach for pathological bone injuries.

This paper introduces conductive biomaterials for peripheral nerve regeneration, which promote axon growth and recovery via electrical signals. Future focus is on interdisciplinary smart conduits, real-time monitoring, and clinical translation.

Inflammation and oxidative stress are among the leading causes of poor prognosis after peripheral nerve injury (PNI). Urolithin-A (UA), an intermediate product produced by the catabolism of ellagitannins in the gastrointestinal tract, has anti-inflammatory, antioxidant, and immunomodulatory properties for inflammation, oxidative damage, and aging-related diseases. Hence, we prepared UA-loaded hydrogels and embedded them in the lumen of PCL nerve guide conduits (NGCs). The hydrogels continuously released appropriate doses of UA into the microenvironment. Based on in vitro studies, UA facilitates cell proliferation and reduces oxidative damage. Besides, the experimental evaluation revealed good biocompatibility of the materials involved. We implanted NGCs into rat models to bridge the sciatic nerve defects in an in vivo study. The sciatic functional index of the PCL/collagen/UA group was comparable to that of the autograft group. Additionally, the consequences of electrophysiological, gastrocnemius muscle and nerve histology assessment of the PCL/collagen/UA group were better than those in the PCL and PCL/collagen groups and close to those in the autograft group. In this study, UA sustained release via the PCL/collagen/UA NGC was found to be an effective alternative treatment for PNI, validating our hypothesis that UA could promote regeneration of nerve tissue.

The integration of conductive polypyrrole and oriented polycaprolactone scaffolds with RSCs fosters a favorable microenvironment for nerve regeneration, especially under electrical stimulation and stem cell differentiation.