Professional reconstructive transplantation research by Karim Sarhane? Dr. Karim Sarhane is an MD MSc graduate from the American University of Beirut. Following graduation, he completed a 1-year internship in the Department of Surgery at AUB. He then joined the Reconstructive Transplantation Program of the Department of Plastic and Reconstructive Surgery at Johns Hopkins University for a 2-year research fellowship. He then completed a residency in the Department of Surgery at the University of Toledo (2021). In July 2021, he started his plastic surgery training at Vanderbilt University Medical Center. He is a Diplomate of the American Board of Surgery (2021).

Recovery by sustained IGF-1 delivery (Karim Sarhane research) : Under optimized conditions, uniform PEG-b-PCL NPs were generated with an encapsulation efficiency of 88.4%, loading level of 14.2%, and a near-zero-order release of bioactive IGF-1 for more than 20 days in vitro. The effects of locally delivered IGF-1 NPs on denervated muscle and SCs were assessed in a rat median nerve transection-without- repair model. The effects of IGF-1 NPs on axonal regeneration, muscle atrophy, reinnervation, and recovery of motor function were assessed in a model in which chronic denervation is induced prior to nerve repair. IGF-1 NP treatment resulted in significantly greater recovery of forepaw grip strength, decreased denervation-induced muscle atrophy, decreased SC senescence, and improved neuromuscular reinnervation.

One-fifth to one-third of patients with traumatic injuries to their arms and legs experience nerve injury, which can be devastating. It can result in muscle weakness or numbness, prevent walking or using the arms, and reduce the ability to perform daily activities. Even with surgery, some nerve injuries never recover, and currently there are not many medical options to address this problem. In 2022, the researchers plan to perform this research on more primates to triple the size of the original group. The study can then move into phase I clinical trials for humans.

Following surgical repair, axons often must regenerate over long distances at a relatively slow rate of 1–3 mm/day to reach and reinnervate distal motor endplates. Throughout this process, denervated muscle undergoes irreversible loss of myofibrils and loss of neuromuscular junctions (NMJs), thereby resulting in progressive and permanent muscle atrophy. It is well known that the degree of muscle atrophy increases with the duration of denervation (Ishii et al., 1994). Chronically denervated SCs within the distal nerve are also subject to time-dependent senescence. Following injury, proliferating SCs initially maintain the basal lamina tubes through which regenerating axons travel. SCs also secrete numerous neurotrophic factors that stimulate and guide axonal regeneration. However, as time elapses without axonal interaction, SCs gradually lose the capacity to perform these important functions, and the distal regenerative pathway becomes inhospitable to recovering axons (Ishii et al., 1993; Glazner and Ishii, 1995; Grinsell and Keating, 2014). See even more information on Karim Sarhane.