Ravi PK, Rout S, Mishra PR, Balamurugan AN. Influence of islet purity on the proportion of smaller islets and graft outcomes in clinical transplantation. World J Transplant 2026; 16(2): 116413 [DOI: 10.5500/wjt.v16.i2.116413]
Corresponding Author of This Article
Praveen Kumar Ravi, MD, Assistant Professor, Department of Anatomy, All India Institute of Medical Sciences, Sijua, Patrapada, Bhubaneswar 751019, Odisha, India. praveenkumar1059@gmail.com
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Transplantation
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review-article
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Ravi PK, Rout S, Mishra PR, Balamurugan AN. Influence of islet purity on the proportion of smaller islets and graft outcomes in clinical transplantation. World J Transplant 2026; 16(2): 116413 [DOI: 10.5500/wjt.v16.i2.116413]
World J Transplant. Jun 18, 2026; 16(2): 116413 Published online Jun 18, 2026. doi: 10.5500/wjt.v16.i2.116413
Influence of islet purity on the proportion of smaller islets and graft outcomes in clinical transplantation
Praveen Kumar Ravi, Sipra Rout, Pravash R Mishra, Appakalai N Balamurugan
Praveen Kumar Ravi, Sipra Rout, Pravash R Mishra, Department of Anatomy, All India Institute of Medical Sciences, Bhubaneswar 751019, Odisha, India
Appakalai N Balamurugan, Wendy Novak Diabetes Institute, Norton Children’s Research Institute, Norton Healthcare, Division of Endocrinology, Department of Pediatrics, Pediatric Research Institute, University of Louisville, Louisville, KY 40202, United States
Co-corresponding authors: Praveen Kumar Ravi and Appakalai N Balamurugan.
Author contributions: Ravi PK and Balamurugan AN conceptualized and conducted the minireview; Both Balamurugan AN and Ravi PK contributed equally as co-corresponding authors; Ravi PK proposed the concept and Balamurugan AN provided the necessary background data from his laboratory to support it. Both Ravi PK and Balamurugan AN analyzed and interpreted the data, which is the key concept on which this manuscript is based. This collaboration between Ravi PK and Balamurugan AN are crucial for the publication of this manuscript. Mishra PR and Rout S supervised the findings and critically analyzed the study; Ravi PK and Rout S drafted the manuscript; Mishra PR and Balamurugan AN critically revised the manuscript; and all authors discussed the results and approved the final manuscript.
Conflict-of-interest statement: All authors declare no conflict of interest in publishing the manuscript.
Corresponding author: Praveen Kumar Ravi, MD, Assistant Professor, Department of Anatomy, All India Institute of Medical Sciences, Sijua, Patrapada, Bhubaneswar 751019, Odisha, India. praveenkumar1059@gmail.com
Received: November 12, 2025 Revised: December 20, 2025 Accepted: February 11, 2026 Published online: June 18, 2026 Processing time: 199 Days and 2.2 Hours
Abstract
The outcome of clinical islet transplantation has been influenced by various factors, including the volume of islet transplanted (IEQ), frequency of transplantation, islet size, and purity. Most studies have compared the outcomes with these factors individually. This review attempts to comprehend the key factors that influence the outcome of clinical islet transplantation by understanding and analyzing the relationship between them. The purity of the islet preparation is often overlooked, as it is often believed to have a higher level of purity associated with better clinical outcome. However, a recent study documented long-term outcome of transplantation is better when purity less than 50%. Various studies have documented the decrease in the proportion of small islets with an increase in purity. Poor clinical outcomes have been documented when the transplanted islet preparation contains a lower proportion of small islets. This is not only because small islets survive better with diffusion, but also the higher proportion of large islets is prone to producing overestimation in IEQ calculation, leading to inadequate transplantation volume. Vigorous purification processes may remove the potential stem cells or progenitor cells present in pancreas and lack the paracrine effect that supports the viability and function of transplanted islets.
Core Tip: The interaction between islet purity and size distribution influences the results of islet transplantation in addition to islet volume. Highly purified preparation prevents the adverse reaction, but it also decreases the small islets proportion and supportive progenitor cells from the preparation. Reduction in small islets leading to overestimation of the islet transplanted, reduced graft viability and function. Smaller islets demonstrate superior survival, revascularization, and insulin secretion, since it survives better with diffusion when compared with larger islets. Hence, moderate rather than maximal purification may preserve small islets, paracrine support, and regenerative potential, improving long-term engraftment and insulin independence.
