Feasibility and Safety of Pancreatic Islet Transplantation in the Liver by Portal Vein Catheterization using the Transjugular Route

Impact of Procedure-Related Complications on Long-term Islet Transplantation Outcome

BACKGROUND

Pancreatic islet transplantation offers a promising biotherapy for the treatment of type 1 diabetes, but this procedure has met significant challenges over the years. One such challenge is to address why primary graft function still remains inconsistent after islet transplantation. Several variables have been shown to affect graft function, but the impact of procedure-related complications on primary and long-term graft functions has not yet been explored.

METHODS

Twenty-six patients with established type 1 diabetes were included in this study. Each patient had two to three intraportal islet infusions to obtain 10,000 islet equivalent (IEQ)/kg in body weight, equaling a total of 68 islet infusions. Islet transplantation consisted of three sequential fresh islet infusions within 3 months. Islet infusions were performed surgically or under ultrasound guidance, depending on patient morphology, availability of the radiology suite, and patient medical history. Prospective assessment of adverse events was recorded and graded using "Common Terminology Criteria for adverse events in Trials of Adult Pancreatic Islet Transplantation."

RESULTS

There were no deaths or patients dropouts. Early complications occurred in nine of 68 procedures. β score 1 month after the last graft and optimal graft function (β score ≥7) rate were significantly lower in cases of procedure-related complications (P = 0.02, P = 0.03). Procedure-related complications negatively impacted graft function (P = 0.009) and was an independent predictive factor of long-term graft survival (P = 0.033) in multivariate analysis.

CONCLUSION

Complications occurring during radiologic or surgical intraportal islet transplantation significantly impair primary graft function and graft survival regardless of their severity.

Insulin independence after islet transplantation through an indwelling catheter in the right gastric vein

BACKGROUND

Current islet transplantation approaches have various defects. This study was to investigate the feasibility and safety of an indwelling catheter in the right gastric vein for intra-hepatic islet transplantation.

METHODS

Twenty patients had islet transplants through the indwelling catheter in the right gastric vein. The catheters were placed into the portal vein trunk using open surgery. While monitored with Doppler ultrasound, the islet suspensions were infused after the catheter location was confirmed in the trunk of the portal vein. The catheter was kept indwelling and secured to the skin for optional subsequent infusions and flushed with heparinized saline once per day to avoid peri-catheter thrombosis. After one month, the catheter was removed. Adverse effects and transplant efficacy parameters were observed.

RESULTS

Insulin independence was finally achieved in 17 patients; 11 patients received a second infusion. The mean surgical duration was 55 ± 7 minutes and the hemorrhage volume was approximately 40 ± 11 mL. No significant change in portal pressure was observed (before infusion 2.9 ± 1.5 cm H₂O, after infusion 2.6 ± 1.7 cm H₂O, p>0.05). However, peak systolic velocity (PRV) of the hepatic artery after infusion was markedly higher than that before infusion (35.1 ± 10.7 cm/s vs. 68.5 ± 46.2 cm/s, p<0.01). Neither infection nor severe hemorrhage was found after surgery.

CONCLUSIONS

It is feasible, convenient, and safe to use an indwelling catheter in the right gastric vein for islet transplantation.

Salicylates increase insulin secretion in healthy obese subjects

CONTEXT

Conflicting results on the effects of salicylates on glucose tolerance in subjects with normal glucose tolerance or type 2 diabetes have been reported.

OBJECTIVE

The objective of the study was to investigate the effects of a salicylate derivative (triflusal) on insulin sensitivity and insulin secretion.

DESIGN, SETTING, AND PARTICIPANTS

This was a double-blind, randomized, crossover study with three treatment periods corresponding to two dose levels of triflusal and placebo in healthy obese subjects.

MAIN OUTCOME MEASURES

Insulin sensitivity and insulin secretion, evaluated through frequently sampled iv glucose tolerance test that was performed after each treatment period, were measured. Insulin secretion was also evaluated in vitro in mice and human islets of Langerhans.

RESULTS

The administration of triflusal led to decreased fasting serum glucose concentration in the study subjects. Insulin sensitivity did not significantly change after each treatment period. Insulin secretion, however, significantly increased in a dose-dependent fashion after each triflusal treatment period. The administration of 800 mum of the main triflusal metabolite to whole mice islets of Langerhans led to a sustained increase in intracellular calcium concentration level. This was followed by a significantly increase in insulin secretion. In human islets, 200 mum of 2-hydroxy-4-trifluoromethylbenzoic acid was sufficient to increase insulin release.

CONCLUSIONS

The administration of a salicylate compound led to lowering of serum glucose concentration. We suggest that this effect was mediated through increased insulin secretion induced by salicylate directly on the beta-cell.

Beta-cell replacement in immunosuppressed recipients: old and new clinical indications

Islet transplantation is an appealing procedure able to improve glycemic control in type 1 diabetic patients. However, the possible side effects that may be induced by immunosuppressive therapy limit its application to a select number of patients for whom the risk of immunosuppressants' side effects can be justified. For patients with type 1 diabetes mellitus-who will take immunosuppressants regardless, as they require a solid organ transplant-islet infusion can be an interesting therapeutic option for improving metabolic compensation, whenever pancreas transplant is not possible. Hence, islet infusion can be an important therapeutic option for patients with secondary diabetes mellitus even when a minor pancreatic endocrine function remains. For these patients, results may be better than those obtained with islet infusion for patients with type 1 diabetes mellitus thanks to the lack of autoimmune reaction to the infused islets. The final result is the improvement of the glycemic compensation and most likely also an extension of the graft survival.

Estado actual del trasplante de islotes pancreáticos

Due to the numerous advances in islet transplantation in the last few years, clinical outcomes following this procedure are continually improving. Novel immunosuppression protocols, improved donor and recipient selection, and careful attention to the process of organ extraction, preservation and islet isolation have contributed to long-term success. The present article reviews the results of clinical islet transplantation and their relationship with the different advances introduced. The use of new islet sources such as living and non-heart-beating donors, as well as recent advances in our knowledge of the mechanisms of rejection and its prevention, are also reviewed.