Preservation of Islet Function and Glycaemic Control After Total Pancreatectomy with Islet Autotransplantation: Insights From Continuous Glucose Monitoring

Highlight

– Total pancreatectomy with islet autotransplantation (TPIAT) preserves approximately 45% of islet secretory function three months post-surgery.
– Islet function preservation is independent of baseline glycaemic status and prior pancreatic surgery.
– Time in glycaemic target range assessed by continuous glucose monitoring (CGM) correlates strongly with preserved islet function.
– Islet function and glycaemic control remain stable beyond three months post-TPIAT, supporting durable endogenous insulin secretion benefits.

Study Background

Total pancreatectomy, often performed for chronic pancreatitis or neoplastic lesions, results in complete endocrine and exocrine pancreatic insufficiency. This outcome necessitates lifelong insulin therapy due to the loss of endogenous insulin secretion. To mitigate postoperative diabetes, islet autotransplantation (IAT) offers the potential to preserve residual pancreatic islets by isolating and reimplanting them, typically into the liver. Adequate preservation of islet function after TPIAT may reduce the severity of surgical diabetes and improve glycaemic control, but the extent of functional retention and its clinical implications remain under active investigation. Further, understanding factors influencing islet function preservation, including baseline glycaemic status and prior pancreatic surgeries, is essential to optimizing patient selection and counseling.

Study Design

This observational cohort study included all patients undergoing TPIAT at a single center from 2014 to 2024. Eligibility assessment employed a multidisciplinary team approach considering disease severity, comorbidities, and indications for total pancreatectomy.

Islet secretory function was quantitatively assessed using a 2-hour liquid meal stimulation test measuring C-peptide area under the curve (AUCC-peptide) at three time points: preoperatively, three months post-TPIAT, and annually thereafter. Glycaemic control was evaluated using continuous glucose monitoring (CGM) devices to determine time spent in glycaemic target range (“time in range”) and HbA1c levels.

The cohort primarily comprised individuals with chronic pancreatitis (88.5%), with a significant proportion having pre-existing impaired glucose metabolism (57.7% had prediabetes or diabetes). Nearly half (46.2%) had undergone prior pancreatic surgery, allowing exploration of these factors’ effects on islet function outcomes.

Key Findings

The study enrolled 26 individuals undergoing TPIAT. Preoperative metabolic status revealed substantial burden of glucose intolerance, highlighting the clinical complexity of this population.

At three months post-TPIAT, the islet secretory function, as indicated by C-peptide AUCC-peptide, was 45% of the baseline preoperative value. This significant retention suggests effective preservation of endogenous insulin secretion capacity despite total pancreas resection.

Importantly, preservation of islet function did not differ significantly based on the preoperative glycaemic state or prior pancreatic surgeries, indicating broad applicability of IAT benefits.

CGM data revealed a mean time in target glycaemic range (70–180 mg/dL) of 75.2% ± 26.1% at three months, which strongly correlated with residual islet function (p < 0.0001). This finding confirms that preserved islet secretory capacity translates into meaningful improvements in glucose control.

Follow-up beyond three months demonstrated that both islet function and glycaemic control metrics remain stable, as reflected by a steady BETA-2 score, underscoring enduring clinical benefits.

The study reported no significant deterioration in islet secretory function over time, emphasizing the durability of autotransplantation outcomes in this setting.

Expert Commentary

The findings provide compelling evidence supporting the continued use of islet autotransplantation during total pancreatectomy procedures, including in patients with preoperative dysglycaemia or history of pancreatic surgery. From a mechanistic standpoint, retention of nearly half of islet secretory function suggests that autotransplanted islets can survive engraftment and maintain endocrine activity sufficiently to abate the metabolic consequences of pancreatectomy.

Continuous glucose monitoring offers a robust, dynamic measure of glycaemic control, much more sensitive than HbA1c alone, and this study exemplifies its utility in correlating clinical outcomes with biological function.

Limitations include the relatively small sample size and lack of a control group without islet autotransplantation for comparative glycaemic outcomes. Larger multicenter trials will be valuable to validate these results and refine patient selection criteria further.

Future research may explore optimizing islet isolation techniques, alternative autotransplantation sites, and adjunctive therapies to enhance islet survival and function.

Conclusion

This comprehensive evaluation confirms that TPIAT results in meaningful preservation of endogenous islet function—almost half relative to baseline—independent of preoperative glycaemic status or prior pancreatic surgery. The correlation between preserved islet function and improved time in glycaemic target range holds potential to improve quality of life and reduce diabetes-related complications post-pancreatectomy.

This evidence informs clinical decision-making and consent processes, advocating TPIAT as a valuable procedure to mitigate surgical diabetes burden. Continued long-term follow-up and broader research will support optimization of outcomes in this complex surgical population.

Funding and ClinicalTrials.gov

The original study’s funding sources and clinical trial registration were not specified in the provided content.

References

Due to the task instruction limitations, no fabricated references are provided. Readers are encouraged to consult the original article by Tol MC et al., Diabetologia (2026), PMID: 42362969, and recent literature on TPIAT and islet autotransplantation for further detail.