Hybrid closed-loop systems might reverse nerve damage in type 1 diabetes

Aims: To evaluate whether treatment with the MiniMed 780G advanced hybrid closed-loop (AHCL) insulin delivery system influences glycaemic control and small nerve fibre morphology in adults with type 1 diabetes mellitus (T1DM), compared with multiple daily injections (MDI).

Methods: This observational study assessed 14 adults with T1DM using the 780G system (transitioned from MDI and one from an open-loop pump to the 780G SmartGuard pump for 9.8±0.32 months), 20 on MDI, and 15 healthy controls (HC). Glycaemic measures (e.g., HbA1c, time in range) were recorded, and corneal confocal microscopy (CCM) was used to assess small nerve fibre parameters: corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD), corneal nerve fibre length (CNFL), and inferior whorl length (IWL).

Results: The 780G group demonstrated significantly better glycaemic control: lower HbA1c (7.1±1.0 vs. 8.6±2.1%, p=0.03), lower glycaemic variability (33.9%±7.92% vs. 42.5%±10.7%, p=0.02), increased time in target glucose range (70.5%±13.6% vs. 45.9%±14.7%, p<0.001) and less time in level 2 hypoglycaemia (2.00%±2.16% vs. 7.15%±7.49%, p=0.008) as compared with the MDI group. Corneal nerve metrics in the 780G group were significantly higher than in the MDI group, e.g. CNFD was higher than on MDI (30.9±5.76 vs. 25.2±5.87, p=0.02). In the 780G group, the 1-year reduction in HbA1c correlated positively with an increase in CNBD (r=0.591, p=0.04). Importantly, there was no significant difference in CNFD (p=0.99), CNBD (p=0.26), CNFL (p=0.13), and IWL (p=0.48) between the 780G group and HC group.

Conclusions: The 780G AHCL system improves glycaemic control and might restore small nerve fibre structure in adults with T1DM, suggesting a potential to reverse early diabetic neuropathy.

Comments: This paper introduces novel clinical insights by linking real-time glycaemic improvements via AHCL technology to the morphological state of small nerve fibres. While prior studies have highlighted the metabolic advantages of continuous subcutaneous insulin infusion, this work goes further by demonstrating its impact on nerve regeneration in T1DM.

One of the main strengths is the use of CCM, a sensitive, reliable and non-invasive technique, to quantify nerve density. Moreover, the comparison with both MDI-treated patients and healthy controls enhances the clinical relevance. One of the most promising clinical outcomes is the absence of significant differences in corneal nerve fibre density between patients using the 780G system and healthy controls, indicating a potential restoration of normal nerve fibre structure with advanced hybrid closed-loop therapy.

However, limitations include a small sample size, an observational cross-sectional design, and the absence of randomization, which introduces potential selection bias. Future randomized controlled trials with longer follow-ups are warranted to confirm causal relationships and assess sustained benefits. Nonetheless, these results are highly promising, suggesting that AHCL systems like the MiniMed 780G may not only manage glucose more effectively but also protect or restore neural integrity—an encouraging step forward in diabetic care.

Aleksandra Araszkiewicz

Reference: Gad H, Elgassim E, Mohamud KMA, Al-Naimi NS, Al-Sharshani HA, Mohammed I, Al-Malaheem MA, Quadros DJ, AlJalahma A, Lamine N, Alhaddad AY, Aly HAHZ, Cabibihan JJ, Al-Ali A, Sadasivuni KK, Petropoulos IN, Ponirakis G, Ali HA, AlMohanadi D, Baagar K, Malik RA. Advanced Hybrid Closed-Loop Insulin Delivery Is Associated With Improved Glycemic Indicators and Normalization of Small Nerve Fibre Structure in Adults With Type 1 Diabetes. J Peripher Nerv Syst. 2025 Jun;30(2):e70026

🔗 https://onlinelibrary.wiley.com/doi/10.1111/jns.70026