(T1130-01-04) Comprehensive Strategy for Type 2 Diabetes: Non-competitive Ligand-Based Oral Delivery of Curcumin Combined with Long-Acting Insulin to Prevent Secondary Complications

Purpose: Managing Type 2 Diabetes (T2D) revolves around maintaining glucose levels within a healthy range, typically starting with a single medication, and advancing to multi-drug treatments. However, despite these efforts, these methods may lose effectiveness over time, resulting in the emergence of secondary complications of diabetes that are difficult to treat/manage. Recent research suggests that integrating anti-inflammatory substances like curcumin into T2D care can reduce oxidative stress and inflammation, leading to improved clinical outcomes and prevent or delay complications. To enhance the therapeutic potential of curcumin, my lab developed non-competitive receptor-mediated drug delivery systems using gambogic acid (GA) as a ligand, where two molecules of GA were coupled to the terminal carboxyl group of PLGA using a tripodal spacer [1]. This study presents an innovative strategy by combining oral curcumin nanoparticles (nCUR) with commercially available long-acting subcutaneous insulin. This approach is backed by previous research conducted by our lab using Type 1 diabetic models[2-4]. The goal of this combined approach is to effectively tackle T2D's vascular complications

Methods: C57BL/6J mice were randomly divided into 8 groups, each containing 8 mice. The Control Group was maintained on a regular diet throughout the study, while Groups 2 to 8 were fed a high-fat diet (HFD) for the entire duration. After 8 weeks on their respective diets, mice in Groups 3 to 8 were administered two low doses of streptozotocin (STZ) to induce Type 2 Diabetes (T2D). Treatment initiation occurred 48 hours post-STZ injections for a duration of 16 weeks. Group 4 (PLGA) and Group 5 (PLGA-GA₂) received two variations of curcumin-encapsulated nanoparticles, without and with the ligand GA respectively. Group 6 (VOID) received empty nanoparticles, Group 7 (INS) was treated with conventional long-acting insulin, and Group 8 (COMBO) received combination therapy consisting of ligand-based curcumin nanoparticles with subcutaneous insulin.

Results: The blood glucose analysis revealed that the COMBO group exhibited superior glucose homeostasis compared to the INS group throughout the 16-week period, maintaining stable 24-hour blood glucose levels (Figure 1). Terminal blood analysis showed a notable decrease in neutrophil and monocyte counts in groups receiving curcumin nanoparticles compared to diabetic G3 (HFD-STZ) animals. This reduction was significantly evident in the INS and COMBO groups. Moreover, lipid profile analysis revealed a significant decrease in Triglycerides, LDL-cholesterol, and total cholesterol in the intervention groups. Examining IL-1β levels in terminal plasma indicated a significant decrease in the treatment groups compared to the diabetic group HFD-STZ, especially pronounced in the INS and COMBO groups (Figure 2). To assess the progression of diabetic kidney disease, urinary biomarkers including KIM-1 and IP-10 were measured. These biomarkers were significantly reduced in the groups receiving curcumin nanoparticles, particularly notable in the COMBO group. Interestingly, this reduction was not observed in the insulin group, suggesting a progression of tubular damage (Figure 3).

Conclusion: In conclusion, our study demonstrates the efficacy of a comprehensive strategy for managing Type 2 Diabetes (T2D) through the combination of non-competitive ligand-based oral delivery of curcumin nanoparticles and insulin therapy. The COMBO group, receiving this combined treatment, exhibited superior glucose homeostasis, stable 24-hour blood glucose levels, and a significant reduction in inflammatory markers compared to the INS group over 16-week period. Moreover, our findings indicate that the intervention groups experienced notable improvements in lipid profiles and reduced neutrophil and monocyte counts, indicating a potential protective effect against diabetic complications. The significant decrease in urinary biomarkers KIM-1 and IP-10 in the groups receiving curcumin nanoparticles, particularly in the COMBO group, underscores the potential for mitigating diabetic kidney disease progression. Overall, our results support the notion that combining curcumin nanoparticles with insulin therapy offers a promising approach to address hyperglycemia, inflammation, and associated complications in Type 2 Diabetes. In addition to the observed improvements, further analysis of tissues is pending, such as histological examination and molecular profiling, which will be crucial in providing a more comprehensive understanding and robust evidence supporting the efficacy of our combined treatment approach in managing Type 2 Diabetes and its complications.

References: [1] G. Kaur, M. Arora, R. Ganugula, M. Kumar, Double-headed nanosystems for oral drug delivery, Chem Commun (Camb), 55 (2019) 4761-4764.
[2] R. Ganugula, N.K. Nuthalapati, S. Dwivedi, D. Zou, M. Arora, R. Friend, D. Sheikh-Hamad, R. Basu, M.R. Kumar, Nanocurcumin combined with insulin alleviates diabetic kidney disease through P38/P53 signaling axis, Journal of Controlled Release, 353 (2023) 621-633.
[3] R. Ganugula, M. Arora, S. Dwivedi, D.S. Chandrashekar, S. Varambally, E.M. Scott, M. Kumar, Systemic Anti-Inflammatory Therapy Aided by Curcumin-Laden Double-Headed Nanoparticles Combined with Injectable Long-Acting Insulin in a Rodent Model of Diabetes Eye Disease, ACS Nano, 17 (2023) 6857-6874.
[4] S. Dwivedi, A. Gottipati, R. Ganugula, M. Arora, R. Friend, R. Osburne, A. Rodrigues-Hoffman, R. Basu, H.L. Pan, M. Kumar, Oral Nanocurcumin Alone or in Combination with Insulin Alleviates STZ-Induced Diabetic Neuropathy in Rats, Mol Pharm, 19 (2022) 4612-4624.

Acknowledgements: This work is supported by NIH-5R01EY028169


Figure 1: Heat map displaying the 24-hour blood glucose profile over a 16-week study period, measured using the AlphaTrak3 Glucometer via tail vein prick


Lipid Panel quantification in terminal plasma was conducted using the Vet Axcel Chemistry Analyzer. IL-1β levels were assessed via a MultiPlex assay


Multiplex Assay Analysis of Kidney Injury Molecule-1 (KIM-1) and Interferon-Gamma-Induced Protein 10 (IP-10) in Terminal Urine Samples