by Michel van der Burg , Sunday 5 July 2026
Abstract
In 1997, Onno Terpstra, Head of Surgery at Leiden University Medical Center (LUMC), asked Michel van der Burg to develop a plan for a clinical islet isolation and transplantation program. Following a working visit to the Diabetes Research Institute in Miami in spring 1998, where the Iodixanol-UWS purification method was tested on human islets, van der Burg began the islet isolation program at LUMC and the setting up of the Clinical Islet Laboratory (Klinisch Eilandlaboratorium, KEL) within a new GMP facility at LUMC, in collaboration with Amon Wafelman, executive head of the GMP facility. A business plan was submitted to the LUMC Board of Directors in November 1998 and approved on February 22, 1999, formally launching the project. The first series of human islet isolations, using manual pancreas digestion and Iodixanol-UWS purification, began in March 1999. The results were published in December 1999 and presented at the AIDSPIT Workshop in January 2000. From 2000 onward, the laboratory adopted the automated Ricordi method, using equipment supplied through BioRep Technologies in Miami.
Citation info : 1999 — Pioneering the LUMC Clinical Islet Transplant Project • 1MEMO_20260705 • Michel van der Burg • Miracles•Media • URL michelvanderburg.com/2026/07/05
The LUMC clinical islet transplantation project began in 1997 on the initiative of the Department of Surgery at the LUMC, where I had been conducting animal-experimental research within the Transplantation Section since 1981 — first into the optimal method for pancreas transplantation, and subsequently into the transplantation of islets of Langerhans following isolation and purification of the islets from the pancreas (1-11).
Following successful animal-experimental islet transplantation, and a brief period of experimental human islet isolation in the early 1990s (8,9), Onno Terpstra, the head of our Surgery Department, asked me in the summer of 1997 to explore our options for starting clinical islet isolation and transplantation at our center — the Leiden University Medical Center (LUMC) — and to prepare a roadmap.
After first gaining experience in the spring of 1998 with the human islet transplant program in Miami — during which, in the course of isolating human islets of Langerhans, our new islet purification method also proved successful (11,12) — I was able to begin actually setting up the human islet project in Leiden in the summer of 1998.
Our innovative procedure for purifying islets in Iodixanol-UWS was further developed and published that summer of 1998 in collaboration with Nycomed (10).
The LUMC had recently begun renovating a wing of the building to establish a GMP facility with 5 so-called cleanrooms, intended to guarantee maximum protection and quality in the manufacture of medicinal products. After the summer of 1998, I was just in time to join those renovation plans, working together with Amon Wafelman — the executive head of the future GMP facility — to realize the necessary modifications in the GMP wing, with one of the 5 cleanrooms specially fitted out for use as our clinical islet laboratory. Although the cleanrooms had not originally been intended for permanent use, round-the-clock use of a cleanroom for the islet project could nonetheless become an option, with support from the Board of Directors.
By November 1998, I had incorporated a plan for setting up the Clinical Islet Laboratory (KEL) — and for the first 20 islet isolation procedures — into a business plan presented on behalf of our Department of Surgery to the LUMC Board of Directors (13; 1MEMO_20260705_1).
On February 22, 1999, the LUMC Executive Board approved the plan and authorized the necessary material resources, officially launching the islet transplantation project — as announced that month in the LUMC magazine ‘Cicero’ (14; 1MEMO_20260705_2).
‘
Quote (my translation):
“The Transplantation of Islets of Langerhans: A Leiden First
… The isolation of islets will take place at the LUMC. What remains is the completion of the GMP facility (Good Manufacturing Practice), the laboratory whose quality standards are so stringent that “products” can be manufactured that are suitable for administration to humans …”
The project was registered with the Eurotransplant organization for the allocation of donor organs — marginal donor organs, i.e. not suitable for clinical transplantation — to start up the islet isolation procedure, without transplantation being the aim at that stage.
In March 1999, we received the first donor organs via Eurotransplant for an initial experimental series of islet isolations. With the approval of the Board of Directors — since the GMP facility was still under construction — work could already begin in the Surgery Laboratory, gaining hands-on experience with human islet isolation, the donor procedure, islet culture, and all other facets of operating an “islet bank.”
In April 1999, the Dutch national newspaper ‘De Volkskrant’ announced the LUMC project in the article “Help for diabetic glands” (“Hulp voor suikerzieke klieren”) by John Ekkelboom (15; 1MEMO_20260705_3), with contributions from Jan Ringers (Head of the Transplantation Section of our department) and myself.
Excerpts (translated from Dutch):
“Help for diabetic glands
Some patients with juvenile diabetes may benefit from a transplantation of islets of Langerhans. Cells from these islets replenish the insulin deficiency. The Leiden University Medical Center (LUMC) will soon treat several patients with this new method.
… Dr. Jan Ringers, a transplant surgeon at the LUMC, says that the chance of success has increased to such an extent that his hospital now also considers the procedure justifiable …
… Dr. Michel van der Burg attributes the fact that this scenario did not go as well abroad in the early years to, among other things, less suitable enzymes and the premature insertion of the transplant. As a scientific researcher at the LUMC, he focuses on the isolation of the islets …”
— John Ekkelboom, April 10, 1999, Volkskrant
First series of human islet isolations in Leiden
In March 1999, the first series of human islet isolations began in the LUMC Surgery Laboratory, applying the manual method of donor pancreas digestion, with purification of the islets in the new Iodixanol-UWS gradients.
This Iodixanol-UWS purification method had been developed in our animal-experimental research on the isolation and purification of porcine islets for successful transplantations, first in diabetic mice, then in rats and monkeys (7,16).
The Iodixanol-UWS purification method had also proved promising the previous year in my pilot research during human islet isolations at the Diabetes Research Institute in Miami, where the purified human islets were successfully transplanted into nude mice (11).
The results of our first series of human islet isolations at the LUMC in 1999 were published in December 1999 and subsequently presented at the 19th AIDSPIT Workshop of the European Association for the Study of Diabetes (EASD) in Igls, Austria, in January 2000 (17,18,19,20; 1MEMO_20260705_4).
No Loss of Human Islets • AIDSPIT 2000 • 1MEMO_20260705_4 • Michel van der Burg • Miracles•Media • Outcome 1st series in 1999 of human islet isolation in LUMC presented at the 19th AIDSPIT Workshop of the European Association for the Study of Diabetes (EASD) in Igls, Austria, January 23–25, 2000 . Details , plus handout and abstract for download in Notes (17,18,19,20).
State of the Art — Ricordi Method & BioRep Technologies
Work then began on the second series of isolations, this time using the state-of-the-art “Ricordi Automated Method” for pancreas digestion (21), as developed by Camillo Ricordi.
In setting up the state-of-the-art procedure for islet isolation from the pancreas using the Ricordi Automated Method at the LUMC, I worked at the end of 1998 together with Gerard Verschagen, head of the precision mechanics workshop of the Laboratory of Physiology of the LUMC (22), on developing a compressed-air-driven shaking device for the Ricordi chamber, for which modifications to the GMP complex were also planned.
Earlier in 1998, during my working visit to the Diabetes Research Institute in Miami, I had met Mr. Ramon Poo, who — alongside his day job as a designer and manufacturer of plastic bottles in Miami (Altira, Inc.) — also contributed on a voluntary basis to Ricordi’s islet project in Miami. Through his firm founded specifically for this purpose, BioRep Technologies, Inc., Poo designed and manufactured the special equipment for the Ricordi isolation method, including the digestion chamber and a shaking device for the Ricordi chamber (23,24). During that working visit, Mr. Poo also gave me a stainless-steel Ricordi chamber and other components for the “Ricordi setup” to start up the procedure in our laboratory in Leiden, Holland, in the LUMC.
During discussions at the end of 1998, by phone and fax, with Mr. Poo about our design in Leiden of the shaking device based on the BioRep model, it emerged that BioRep could supply us with a new model of shaking device — the Wrist Shaker, a model not yet patented — with the permission of Camillo Ricordi’s team, on condition of “no disclosure.”
From 1999 onward, the Wrist Shaker (Model No. B-3-G) and other BioRep equipment were imported, after which, from 2000 onward, the Ricordi Automated Method for pancreas digestion was applied for islet isolation at the LUMC…to be continued…
Notes
1) Pancreatic islet transplantation Thesis Repository Leiden University • 20221125 • Michel van der Burg • Miracles•Media • . Persistent URL https://hdl.handle.net/1887/3486604
2) Leiden Islet Laboratory History • 20240803 • Michel van der Burg • michelvanderburg•com • URL https://michelvanderburg.com/2024/08/03/leiden-islet-laboratory-history-20240803/
3) Pancreas & Islet Transplantation Program • 20240912 • Michel van der Burg • michelvanderburg•com • URL https://michelvanderburg.com/2024/09/12/pancreas-islet-transplantation-program-20240912/
4) Pancreatic Islet Isolation With UW Solution • A New Concept • Michel van der Burg • Miracles.Media • @1MEMO 20241224 • URL michelvanderburg.com/2024/12/24/
5) Percoll UWS Purification Pancreatic Islets • ESOT 1991 Talk • Michel van der Burg • Miracles.Media • @1MEMO 20250114 • URL michelvanderburg.com/2025/01/14/
6) Islet Transplantation Breakthrough in Leiden University Hospital • 20240830 • Michel van der Burg • michelvanderburg•com URL https://michelvanderburg.com/2024/08/30/islet-transplantation-breakthrough-in-leiden-university-hospital-20240830/
7) Successful Islet Transplantation After Purification in Iodixanol-UWS • IPITA 1999 Sydney • @1MEMO 20260326 • Michel van der Burg • Miracles.Media • URL michelvanderburg.com/2026/03/26/
8) 1989 — First series of human islet isolations in Leiden
In 1989-1990 we performed a first series of islet isolations from human donor pancreases using our novel techniques of isolation and purification in UW organ preservation solution – in association with a European Concerted Action for the Treatment of Diabetes – the Brussels headed (Daniel Pipeleers) ‘Multicenter program on the treatment of diabetes by islet cell transplantation’.
9) Pittsburgh 1992 Cell Transplant Society • 20240812 • Michel van der Burg • michelvanderburg•com • URL https://michelvanderburg.com/2024/08/12/pittsburgh-1992-cell-transplant-society-20240812/
10) Islet purification from bench to bedside • @1MEMO_20260623 • Michel van der Burg • Miracles.Media • URL michelvanderburg.com/2026/06/23/
11) Efficacy of the novel iodixanol-UWS density gradient for human islet purification • Igls Aidspit 1999 • Michel van der Burg • Miracles.Media • 20241202 • URL michelvanderburg.com/2024/12/02/
12) Human Islet Isolation • DRI Miami 1998 • Michel van der Burg • Miracles.Media • @1MEMO 20250204 • URL michelvanderburg.com/2025/02/04/
13) Business Plan CITX • 1MEMO_20260705_1 • Michel van der Burg • Miracles•Media • TakeNode 62317860-28ff-46a6-9e2b-20910f7f4aa6 • Business plan Clinical Islet Transplantation Project (CITX) prepared November 3, 1998 for the Board of Directors of the LUMC (English translation by author). PDF for viewing and download below 1MEMO_20260705_1.
14) A Leiden First • 1MEMO_20260705_2 • Miracles•Media • TakeNode d3d3effe-ee4c-479c-8051-c78a90746eb1 • “The Transplantation of Islets of Langerhans : A Leiden First “. Pull quote from the feature story ‘Ernstiger ziek en wèl genezen’ by Evert Pronk, in the LUMC news magazine Cicero, 5 February 1999 (ISSN 0920-2900) .
15) Help for diabetic glands • April 1999 News Volkskrant • 1MEMO_20260705_3 • Miracles•Media • TakeNode ccbd39ce-9498-4bc9-aefb-96ae6f9e5791 • Help for diabetic glands (dutch: Hulp voor suikerzieke klieren) in Dutch national newspaper De Volkskrant , 10 April 1999 , by John Ekkelboom . Text (only) online in Volkskrant archive URL https://www.volkskrant.nl/wetenschap/hulp-voor-suikerzieke-klieren~b7046616/
16) Primate Islet Isolation and Purification in Iodixanol-UWS • @1MEMO_20260425 • Michel van der Burg • Miracles.Media • URL michelvanderburg.com/2026/04/25/
17) Van der Burg MPM, Ringers J, Baranski A, Bouwman E, Terpstra OT. No loss of human (mantle-) islets by OptiPrep-UWS purification following isolation in UWS. 19th AIDSPIT Workshop of the European Association for the Study of Diabetes (EASD) in Igls (Austria) Jan 23–25, 2000 . Abstract (Page 230) in : Acta Diabetol 36, 205–231 (1999). https://doi.org/10.1007/s005920050168 . PMID: 10664329
18) No Loss of Human Islets • AIDSPIT 2000 • 1MEMO_20260705_4 • Michel van der Burg • Miracles•Media • Video of slideshow TakeNode bb4091a1-374f-4a04-86a1-67e371074109 • URL https://youtu.be/txSFax_nR2I
19) Ibid. Handout of slideshow : 1MEMO_20260705_4_PDF • Michel van der Burg • Miracles•Media • TakeNode 35766a9b-d1b1-47af-9371-4edca9c3ad0d • Download PDF below ( 1MEMO_20260705_4_PDF )
20) Van der Burg MPM, Ringers J, Baranski A, Bouwman E, Terpstra OT. No loss of human (mantle-) islets by OptiPrep-UWS purification following isolation in UWS (Abstract). Acta Diabetol 36, 230 (1999). URL https://doi.org/10.1007/s005920050168 . PMID: 10664329
Ibid. Abstract copy : 1MEMO_20260705_4_PMID_10664329 • Michel van der Burg • Miracles•Media • TakeNode fa10d5e9-3df9-46e0-b8cf-7f9f9f853526 • Download PDF below ( 1MEMO_20260705_4_PMID_10664329 )
21) Piemonti L, Pileggi A. 25 YEARS OF THE RICORDI AUTOMATED METHOD FOR ISLET ISOLATION. CellR4 Repair Replace Regen Reprogram. 2013;1(1):e128. PMID: 30505878; PMCID: PMC6267808. URL https://pmc.ncbi.nlm.nih.gov/articles/PMC6267808/
22) Leiden Islet Isolation Chamber • Michel van der Burg • Miracles.Media • @1MEMO 20250116 • URL michelvanderburg.com/2025/01/16/
23) How a Family Business Has Buoyed the Diabetes Research Institute (DRI) URL https://www.mwhoskinsmedia.com/2019/12/how-family-business-has-buoyed-diabetes.html
24) Who we are. Biorep. URL https://biorep.com/who-we-are/
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Citation info : 1999 — Pioneering the LUMC Clinical Islet Transplant Project • 1MEMO_20260705 • Michel van der Burg • Miracles•Media • URL michelvanderburg.com/2026/07/05
