Peripheral nerve regeneration research studies with Karim Sarhane in 2022? We performed a study with rodents and primates that showed this new delivery method provided steady release of IGF-1 at the target nerve for up to 6 weeks,” Dr. Karim Sarhane reported. Compared to animals without this hormone treatment, IGF-1 treated animals (rodents and primates) that were injected every 6 weeks showed a 30% increase in nerve recovery. This has the potential to be a very meaningful therapy for patients with nerve injuries. Not only do these results show increased nerve recovery but receiving a treatment every 6 weeks is much easier on a patient’s lifestyle than current available regiments that require daily treatment.
Dr. Sarhane is published in top-ranked bioengineering, neuroscience, and surgery journals. He holds a patent for a novel Nanofiber Nerve Wrap that he developed with his colleagues at the Johns Hopkins Institute for NanoBioTechnology and the Johns Hopkins Department of Neuroscience (US Patent # 10500305, December 2019). He is the recipient of many research grants and research awards, including the Best Basic Science Paper at the Johns Hopkins Residents Research Symposium, the Basic Science Research Grant Prize from the American Foundation for Surgery of the Hand, the Research Pilot Grant Prize from the Plastic Surgery Foundation, and a Scholarship Award from the American College of Surgeons. He has authored to date 46 peer-reviewed articles, 11 book chapters, 45 peer-reviewed abstracts, and has 28 national presentations. He is an elected member of the Plastic Surgery Research Council, the American Society for Reconstructive Microsurgery, the American Society for Reconstructive Transplantation, and the American Society for Peripheral Nerves.
The hydrogels were soaked in IGF-1 solutions, with concentrations ranging from 0.05 to 1 mg/ml. The duration of soaking time and biomaterials used for fabrication differed between studies, thereby complicating further direct comparisons beyond individual consideration. Regardless of concentration of IGF-1 soaking solution, duration of soaking time, or hydrogel composition, the fundamental property in predicting utility for nerve regeneration is the sustained concentration of released IGF-1 that is reaching the site of PNI. Unfortunately, only two of the studies included in Table 6 quantified IGF-1 release in vivo using either fluid sampling with ELISA or radiolabeled IGF-1 (Yuan et al., 2000; Kikkawa et al., 2014). Using ELISA, one study reported significantly greater in vivo IGF-1 concentration, peaking at 1.25 µg/mL at Post-operative Day 1 (POD 1) and returning to the physiologic levels of the control group by POD 7 (Kikkawa et al., 2014). Using radiolabeling, the other in vivo quantification study reported a biphasic IGF-1 release profile with an initial burst of approximately 80% of the starting concentration of IGF-1 at 1 h followed by sustained release of the remaining 15% ± 2.9% over the subsequent 48-h period (Yuan et al., 2000). Conversely, a different study reported failure of IGF-1 to prevent motoneuron death, a finding which was noted to be contrary to previous results and required additional investigation. This study described the use of a soaked gel foam plug but did not specify the IGF-1 release profile of this material (Bayrak et al., 2017). As such, further analysis and testing is needed to determine the optimal fabrication parameters, loading strategy, and concentration of released IGF-1 required for successful local delivery via hydrogel.
Recovery with sustained IGF-1 delivery (Karim Sarhane research) : Functional recovery following peripheral nerve injury is limited by progressive atrophy of denervated muscle and Schwann cells (SCs) that occurs during the long regenerative period prior to end-organ reinnervation. Insulin-like growth factor 1 (IGF-1) is a potent mitogen with well-described trophic and anti-apoptotic effects on neurons, myocytes, and SCs. Achieving sustained, targeted delivery of small protein therapeutics remains a challenge.
Peripheral nerve injuries (PNIs) affect approximately 67 800 people annually in the United States alone (Wujek and Lasek, 1983; Noble et al., 1998; Taylor et al., 2008). Despite optimal management, many patients experience lasting motor and sensory deficits, the majority of whom are unable to return to work within 1 year of the injury (Wujek and Lasek, 1983). The lack of clinically available therapeutic options to enhance nerve regeneration and functional recovery remains a major challenge.
Peripheral nerve injuries (PNIs) affect approximately 67 800 people annually in the United States alone (Wujek and Lasek, 1983; Noble et al., 1998; Taylor et al., 2008). Despite optimal management, many patients experience lasting motor and sensory deficits, the majority of whom are unable to return to work within 1 year of the injury (Wujek and Lasek, 1983). The lack of clinically available therapeutic options to enhance nerve regeneration and functional recovery remains a major challenge.