Ameenuddin, Syed

Introduction: The prevalence of diabetes mellitus (DM) is increasing, and it is associated with cardiorenal dysfunction. Natriuretic peptides (NPs) have cardiorenal protective actions and enhance insulin sensitivity. We designed a dual-action bispecific peptide (CRRL 094) that simultaneously activates the natriuretic peptide system and induces insulin secretion. Methods: To test the in vivo effects of the peptide, Wistar rats (male, 6-8-week-old) were made diabetic by intraperitoneal Streptozotocin (STZ) injection (65 mg/kg). One week after STZ injection, diabetes was confirmed (fasting blood glucose > 350 mg/dL). Rats were then divided into 2 groups: controls (Ctrl group, n=6) and treatment group (Tx group, n= 9). The peptide (1 pmol/kg/min) was infused in the Tx group for 150 min. Results: After 150 minutes of peptide infusion, plasma insulin (mean± standard deviation) increased more than 3.7x among the Tx group compared to the Ctrl group (0.294± 0.199 ng/mL vs 0.078± 0.021 ng/mL, p=0.01). Additionally, plasma glucose decreased among Tx group (405.3±96.4 mg/dL) compared to Ctrl group (545.6± 52.8 mg/dL, p=0.003). Furthermore, the rate of natriuresis increased significantly among the Tx group compared to controls (1.582±0.7 vs 0.639±0.21, p= 0.009), as did the rate of kaliuresis (3.1± 1.1 vs 2.0±0.6, p=0.045). Importantly, the glomerular filtration rate increased by 1.5x among the Tx group compared to the controls (1.6±0.5 vs 1.0±0.3, p= 0.03). There were no significant differences in mean arterial pressure or heart rate. Conclusions: The dual-action insulin-secreting natriuretic peptide (CRRL 094) was effective in increasing endogenous insulin secretion, enhancing natriuresis, and improving renal clearance. Further studies are warranted to assess its long-term safety and efficacy in diabetes.

Object Glial scar and cystic formation greatly contribute to the inhibition of axonal regeneration after spinal cord injury (SCI). Attempts to promote axonal regeneration are extremely challenging in this type of hostile environment. The objective of this study was to examine the surgical methods that may be used to assess the factors that influence the level of scar and cystic formation in SCI. Methods In the first part of this study, a complete transection was performed at vertebral level T9–10 in adult female Sprague-Dawley rats. The dura mater was either left open (control group) or was closed using sutures or hyaluronic acid. In the second part of the study, complete or subpial transection was performed, with the same dural closure technique applied to both groups. Histological analysis of longitudinal sections of the spinal cord was performed, and the percentage of scar and cyst formation was determined. Results Dural closure using sutures resulted in significantly less glial scar formation (p = 0.0248), while incorporation of the subpial transection surgical technique was then shown to significantly decrease cyst formation (p < 0.0001). Conclusions In this study, the authors demonstrated the importance of the vasculature in cyst formation after spinal cord trauma and confirmed the importance of dural closure in reducing glial scar formation.