Quantification of canine pancreatic islet isolation • 1st IPITA 1988 • @1MEMO 20251206


Quantification of canine pancreatic islet isolation • 1st IPITA , Stockholm (Sweden) March 27–29 1988 • Digitally remastered by author, publisher, Michel van der Burg • Miracles•Media • 1MEMO_20251206_01 • TakeNode 430989b2-52f0-4e36-8dbd-cf7bf030668c • #IEQ #diabetes #islets #transplant #methods #LUMC #IPITA

After founding the Leiden Islet Laboratory (1) in the University Hospital Leiden in Holland (later known as LUMC), and reporting the outcome of our first year of canine islet research at a national meeting November 1987 (2), next, this first poster ‘Quantification of canine pancreatic islet isolation’ for a world congress was presented March 1988 at the First International Congress on Pancreatic and Islet Transplantation (IPITA)* in Stockholm, Sweden (3,4).

This pilot work introduced our novel approach of volume quantification of islet isolation outcome by measuring the volume of the isolated islets . In addition we compared the outcome with the total volume of islets measured in the canine pancreas.
Note, that a similar approach, using islet volume measurements for the quantification in islet isolation assessment in man and large animals, was proposed the next year in an International Workshop during the 2nd Congress on Pancreas and Islet Transplantation, Sep. 1989, in Minneapolis, by Camillo Ricordi and some 150 participants from 30 institutes actively involved in islet isolation and transplantation — proposing a procedure for standardized islet volume measurements (based on the number of islets in diameter classes incrementing 50 µm) and reporting outcome in Equivalent Islet Numbers (total volume expressed in the equivalent number of spheres with a 150 µm diameter; abbreviated as EIN, currently known as the number of IEQs (Islet EQuivalents), which greatly enhanced islet research (5).

Unfortunately back problems prevented me to attend that 1st IPITA congress, I was looking forward to, but, fortunately, the poster was presented by my colleagues Hein Gooszen (Surgery Department) and Marijke Frölich (Chemical Pathology Department) of the University Hospital Leiden. Ms. Marijke Frölich also presented a nice poster (7,8) on our quantification of the islets cells , the hormones, in the right lobe (aka , the duodenal segment , the ventral lobe) and left lobe of the canine pancreas (aka, the body and distal tail , the dorsal lobe) of the beagle pancreas , showing the diversity of the islets in these two segments of the pancreas — corresponding to the head and tail of the human pancreas, respectively.
Below the excellent airbrush work by an artist from the Audiovisual Services of Leiden University, for our poster ‘Distribution of insulin, glucagon, pancreatic polypeptide and somatostatin in the canine pancreas’.

Airbrush art on poster board created by the Audiovisual Services of Leiden University. Showing the location of pancreatic tissue sampled from the proximal and distal part of the right and left lobe of the beagle pancreas. The hormone values did not differ significantly between the proximal and distal parts of each lobe. Michel van der Burg • Miracles•Media • 1MEMO_20251206_02 • TakeNode 10b1d696-9d7f-4fa3-a8f9-7a3211546f24


Poster board showing the distribution of the four different types of islet cells by assessment of the hormones insulin, glucagon, pancreatic polypeptide, and somatostatin between the right lobe (RL) and left lobe (LL) of the canine pancreas. The number of insulin, glucagon, and PP producing islet cells differs considerably between both lobes. Michel van der Burg • Miracles•Media • 1MEMO_20251206_03 • TakeNode 47333616-b85d-404e-b103-2ccb3b86d406

I created the original 1988 poster ‘Quantification of canine pancreatic islet isolation’ on March 9-10, 1988 using MacDraw on a personal Macintosh ED , using the bold Chicago font, and the Imagewriter-II matrix printer , except for the header provided by my colleagues , which was together with my colleagues’ posters designed and produced as usual at the time on rigid foam boards by the Audiovisual Services department of the Leiden University. Also the original photo print was pinned on the mounted poster (thus, not digitally processed at the time).
This digital remastered 2025 edition (1MEMO_20251206_1) was produced in LibreOffice Vanilla with conversion of the original 1988 MacDraw file, correcting the disrupted formatting, replacing the non-available Chicago font with the font ‘Chalkboard’ , adding a scan of the Figure 1 photo print , plus a recent photo taken of the original poster board, archived, header. Figure 1 uses a copy of that original photo print , with the addition now, in this remastered edition, of arrows helping identifying the islets , and addition of the text ‘(arrrows)’ in the figure legend.

Other papers presented at the 1st IPITA congress from our research group, on pancreas transplantation, are listed below (9,10,11,12).

David Sutherland

Several other centers reported at this 1st IPITA on succesful islet autotransplantation in large animals, including a series of presentations on canine islet transplantation from David Sutherland’s islet research group in Minneapolis.

We had already started collaborating, by the end of 1987, with David Sutherland and Ms. Jane Field , the head of Sutherland’s islet research laboratory in Minneapolis , planning Jane’s working visit for June 1988 in our Leiden Islet Laboratory, in order to help me set up in Leiden, the current Minneapolis procedure for canine islet isolation and transplantation (13,14).

The next year, Sep-Oct 1989, I worked again with Jane Field and David Sutherland, now in Minneapolis (14,15,16) in the islet research laboratory mostly, and also observing David Sutherland at work during clinical segmental pancreas autotransplantaton, where I made this portrait photograph (1MEMO_20251206_06).

David Sutherland • Clinical Pancreas Transplant, Minneapolis, 1989 • Michel van der Burg • Miracles.Media • 1MEMO_20251206_06 • TakeNode f4769bdf-c7a8-436a-bc5c-2d1505226c05 • David Sutherland performing a clinical segmental pancreas autotransplantation, Minneapolis, 1989. Photo by Michel van der Burg . URL https://michelvanderburg.com/2025/12/06

David Sutherland, the ‘father’ of pancreas and islet transplantation, passed away March 25, 2025.

David jokingly called the pancreas the “Big Dirty Island”.

Notes

* The founding meeting of the IPITA was being held actually at the 4th IPITA meeting — the 4th International Congress on Pancreas and Islet Transplantation — June 27–30, 1993 in Amsterdam (The Netherlands) hosted by Dr. Reinout van Schilfgaarde.

1. Leiden Islet Laboratory History • 20240803 • Michel van der Burg • michelvanderburg•com • URL https://michelvanderburg.com/2024/08/03/leiden-islet-laboratory-history-20240803/

2. Cradle of Islet Transplants • 20240829 • Michel van der Burg • michelvanderburg•com • https://michelvanderburg.com/2024/08/29/cradle-of-islet-transplants-20240829/

3. Van der Burg MPM, Gooszen HG, Terpstra JL, Frölich M, Scherft JP, Lemkes HHPJ. Quantification of canine pancreatic islet isolation. First International Congress on Pancreatic and Islet Transplantation, Stockholm (Sweden) March 27–29, 1988. (Poster). Remastered 2025 poster edition : 1MEMO_20251206_01.

4. Van der Burg MPM, Gooszen HG, Terpstra JL, Frölich M, Scherft JP, Lemkes HHPJ. Quantification of canine pancreatic islet isolation (Abstract). Diabetes 1989; 38 (Suppl. 1): 274. (Abstract). View/Download file 1MEMO_20251206_04

5. Quantitative And Qualitative Standards For Islet Isolation Assessment In Man And Large Mammals. International Workshop during the 2nd Congress on Pancreas and Islet Transplantation. Camillo Ricordi. Archive Michel van der Burg • Miracles•Media • 1MEMO_20251206_07 • TakeNode 3d90aa54-9fe1-4b29-8161-aa6c4fda6652 • View/Download file 1MEMO_20251206_07

6. Ricordi C, Gray DW, Hering BJ, Kaufman DB, Warnock GL, Kneteman NM, Lake SP, London NJ, Socci C, Alejandro R, et al. Islet isolation assessment in man and large animals. Acta Diabetol Lat. 1990 Jul-Sep;27(3):185-95. doi: 10.1007/BF02581331. PMID: 2075782.

7. Frölich M, Van der Burg MPM, Gooszen HG, Jansen JBMJ, Lamers CBHW. Distribution of insulin, glucagon, pancreatic polypeptide and somatostatin in the canine pancreas. First International Congress on Pancreatic and Islet Transplantation, Stockholm, Sweden, March 27–29 1988. (Poster).

8. Frölich M, Van der Burg MPM, Gooszen HG, Jansen JBMJ, Lamers CBHW. Distribution of insulin, glucagon, pancreatic polypeptide, and somatostatin in canine pancreas (Abstract). Diabetes 1989; 38 (Suppl. 1): 257. (Abstract) . Download file 1MEMO_20251206_04

9. Gooszen HG, Van der Burg MPM, Guicherit OR, Jansen JBMJ, Van Schilfgaarde R, Lamers CBHW, Frölich M. A crossover study on the effects of duct obliteration, coeliac denervation and autotransplantation on glucose and meal stimulated insulin, glucagon and pancreatic polypeptide levels. First International Congress on Pancreatic and Islet Transplantation, Stockholm, Sweden, March 27–29 1988. (Talk).

10. Gooszen HG, van der Burg MP, Guicherit OR, Jansen JB, Frölich M, van Schilfgaarde R, Lamers CB. Crossover study on effects of duct obliteration, celiac denervation, and autotransplantation on glucose- and meal-stimulated insulin, glucagon, and pancreatic polypeptide levels. Diabetes. 1989 Jan;38 Suppl 1:114-6. doi: 10.2337/diab.38.1.s114. PMID: 2642831. (Proceedings paper).

11. Gooszen HG, Van Schilfgaarde R, Van der Burg MPM, van Lawick van Pabst WP, Frölich M, Bosman FT. Quantitative assessment of changes in insulin secretion after canine ductobliterated segmental pancreatic autotransplantation in relation to the histological background. First International Congress on Pancreatic and Islet Transplantation, Stockholm, Sweden, March 27–29 1988. (Poster).

12. Gooszen HG, Van Schilfgaarde R, Van der Burg MPM, Van Lawick van Pabst WP, Frölich M, Bosman FT. Quantitative assessment of changes in insulin secretion after canine duct-obliterated segmental-pancreas autotransplantation in relation to histological background (Abstract). Diabetes 1989; 38 (Suppl. 1): 255–256. (Abstract). View/Download file 1MEMO_20251206_05

13. December 1987 , we started planning together Jane Field’s working visit thanks to our nephrologist Fokko van der Woude who after post doc research in Minneapolis had just started as an associate Professor at the Leiden University , working in our Leiden University Hospital (LUMC). Fokko J. van der Woude (1953-2006) passed away too soon after a long battle with cancer.

14. Pancreas & Islet Transplantation Program • 20240912 • Michel van der Burg • michelvanderburg•com • URL https://michelvanderburg.com/2024/09/12/pancreas-islet-transplantation-program-20240912/

15. Visiting research fellow in the Department of Surgery at the University of Minnesota (DER Sutherland, MD PhD) & Department of Cell Biology (OD Hegre, MD PhD), University of Minnesota, Minneapolis Minnesota (USA) , September 14-October 6 1989

16. 2nd International Congress on Pancreatic and Islet Transplantation, and 4th International Symposium on Organ Procurement and Preservation. Minneapolis (USA) September 17–22, 1989.

Citation info : Quantification of canine pancreatic islet isolation • 1st IPITA 1988 • Michel van der Burg • Miracles.Media • @1MEMO 20251206 • URL https://michelvanderburg.com/2025/12/06

Assessment of isolated islet equivalents • Cell Transplant Society 1996 • @1MEMO 20251205

Assessment of isolated islet equivalents • Cell Transplant Society 1996 • Michel van der Burg • Miracles.Media • 1MEMO_20251205_1 • Poster 3rd International Congress Cell Transplant Society, Miami (USA) Sep 29 – Oct 2, 1996



Assessment of isolated islet equivalents • Cell Transplant Society 1996 • Michel van der Burg • Miracles.Media • 1MEMO_20251205_1 • Poster 3rd International Congress Cell Transplant Society, Miami (USA) Sep 29 – Oct 2, 1996 • TakeNode 1300e7cd-85a4-4cd0-9cbc-a88746e625ab • #IEQ #diabetes #islets #transplant #methods #CTRMS

IEQ – Islet Equivalent

IEQ islet stands for Islet Equivalent, a standard unit used to measure the total volume of islets (clusters of insulin cells and other hormone-producing cells in the pancreas). It is defined as a single spherical islet with a diameter of 150 µm. The IEQ is a crucial parameter for assessing the quantity of islets for procedures like clinical islet transplantation, which is a treatment for type 1 diabetes.

Modified international procedure

Following a consensus report in 1989 – 1990 by Ricordi et al (1a, 1b) on islet isolation assessment, the total volume of isolated islets is generally expressed in the number of islet equivalents (IEQs) — defined as islets of 150 µm diameter— and many centers use the advocated now classic international procedure (CIP) of sizing all islets in classes with 50-µm increments (i.e., 50–100, 100–150, etc.) for calculation of the number of IEQs. For each class the number of IEQs are calculated by multiplying the islet counts with a conversion factor — based on the mean volume of that class.

A modified international procedure — based on our conventional Leiden procedure (2,3) with islet sizing in classes with 25-µm increments — is suggested for accurate assessment of the IEQs especially when isolation yields mostly smaller islets, in our paper ‘Assessment of isolated islet equivalents’ presented at the 3rd International Congress Cell Transplant Society, Miami (USA) Sep 29 – Oct 2, 1996, in both a poster (4) , and proceedings paper (5). A photo of the original poster , (retrieved somewhat wrinkled 30 years later from my archive), is posted here, as well as a pdf from the (corrected proof) manuscript of the proceedings paper below (6).

The Cell Transplant Society was founded in 1991, and has been renamed the Cell Transplant and Regenerative Medicine Society (CTRMS).

Notes

1a. Ricordi C, Gray DW, Hering BJ, Kaufman DB, Warnock GL, Kneteman NM, Lake SP, London NJ, Socci C, Alejandro R, et al. Islet isolation assessment in man and large animals. Acta Diabetol Lat. 1990 Jul-Sep;27(3):185-95. doi: 10.1007/BF02581331. PMID: 2075782.

1b. Quantitative And Qualitative Standards For Islet Isolation Assessment In Man And Large Mammals. International Workshop during the 2nd Congress on Pancreas and Islet Transplantation (1989). Camillo Ricordi. Archive Michel van der Burg • Miracles•Media • 1MEMO_20251206_07 . Available from Dec 6, 2025 URL https://michelvanderburg.com/2025/12/06/

2. Van der Burg MPM, Guicherit OR, Frölich M, Scherft JP, Prins FA, Bruijn JA, Gooszen HG. Assessment of islet isolation efficacy in dogs. Cell Transplant. 1994 Jan-Feb;3(1):91-101. doi: 10.1177/096368979400300113. PMID: 8162296.

3. Paper (Notes 2) included as Chapter 3 in my doctoral thesis (Leiden University, November 1994) : Assessment of islet isolation efficacy in dogs. In : Van der Burg MPM. Pancreatic islet transplantation: studies on the technique and efficacy of islet isolation and transplantation ( Chapter 3). (Doctoral Thesis, Leiden University, 1994), Paperback (1994, Nov 9) Boskoop: Van der Burg (ISBN 9080216410); E-book (2022, Oct 25) Boskoop: Michel van der Burg | Miracles•Media ( ISBN 9789080216402). Retrieved (Nov 24th, 2025) from Leiden University Scholarly Publications, Persistent URL https://hdl.handle.net/1887/3486604 . Direct link to file Chapter 3 , URL https://scholarlypublications.universiteitleiden.nl/access/item%3A3486610/view

4. Van der Burg MPM, Scheringa M, Basir I, Bouwman E. Assessment of isolated islet equivalents. Poster presented at the Third Int. Congress Cell Transplant Soc., Miami (USA) Sept. 29 – Oct. 2, 1996.
In : Assessment of isolated islet equivalents • Cell Transplant Society 1996 • Michel van der Burg • Miracles.Media • @1MEMO 20251205 • URL https://michelvanderburg.com/2025/12/05 • File 1MEMO_20251205_1 • TakeNode 1300e7cd-85a4-4cd0-9cbc-a88746e625ab

5. Van der Burg MPM, Scheringa M, Basir I, Bouwman E. Assessment of isolated islet equivalents. Transplant Proc. 1997 Jun;29(4):1971-1973. doi: 10.1016/s0041-1345(97)00188-7. PMID: 9193483.

6. Manuscript (corrected proof for Transplant Proc paper PMID: 9193483). Van der Burg MPM, Scheringa M, Basir I, Bouwman E. Assessment of isolated islet equivalents • 1MEMO_20251205_2 • TakeNode 48380f3c-b3f7-416e-90bb-ad6c53129e46 • PDF available below File 1MEMO_20251205_2

#IEQ #diabetes #islets #transplant #methods #CTRMS

Citation info : Assessment of isolated islet equivalents • Cell Transplant Society 1996 • Michel van der Burg • Miracles.Media • @1MEMO 20251205 • TakeNode 1300e7cd-85a4-4cd0-9cbc-a88746e625ab / 48380f3c-b3f7-416e-90bb-ad6c53129e46 • URL https://michelvanderburg.com/2025/12/05

GLP-1 blood sugar regulation in islet transplants • AIDSPIT 1994 • @1MEMO 20251114

Poster 13th Workshop of the AIDSPIT Study Group , Igls (Austria) January 23–25, 1994• Digitally remastered by author, publisher, M.P.M. van der Burg • Miracles•Media • 20251114 • TakeNode 810cc881-d084-4d2e-b252-d432918b1946 • #GLP1

GLP-1 blood sugar regulation in islet transplants

GLP-1 (glucagon-like peptide-1) is now well-known from the anti-diabetic drugs that mimic the action of this natural hormone GLP-1, to treat type 2 diabetes and obesity. They work by stimulating insulin release, reducing glucagon secretion, slowing stomach emptying, and suppressing appetite, which leads to lower blood sugar and weight loss.

May 1992 we were the first to show direct potentiation of the insulin response from isolated islets by a (near-)physiological dose of the gut hormone GLP-1 during perifusion (in vitro) of canine islets at 7.5-10 mM glucose levels (1,2).

Jan 1994 we next showed this incretin effect of GLP-1 also after islet transplantation (in vivo, in dogs) in this poster (3) and abstract (4) presented at the 13th Workshop of the AIDSPIT (aka AIDPIT) Study Group , Igls, Austria, January 23–25, 1994.

Background of the work was posted earlier this year (5) and the work was published Nov 1994 in my PhD thesis Pancreatic islet transplantation , available online (6).

Notes

1) Van der Burg MPM, Guicherit OR, Scherft JP, Frölich M, Terpstra JL, Gooszen HG. Function after intrasplenic transplantation of islets of Langerhans in dogs (translated from dutch: Functie na intralienale transplantatie van eilandjes van Langerhans in de hond). Surgeon days ’92 of the Dutch Surgery Society, Rotterdam (The Netherlands) May 21–22, 1992. In : Gut factors controlling pancreatic islets • 20240910 | Michel van der Burg | michelvanderburg•com URL https://michelvanderburg.com/2024/09/10/gut-factors-controlling-pancreatic-islets-20240910/

2) van der Burg MPM, Guicherit OR, Frölich M, Gooszen HG. Insulinotropic effects of cholecystokinin, gastric inhibitory polypeptide and glucagon-like peptide-1 during perifusion of short-term cultured canine isolated islets. Regul Pept. 1995 Dec 7;60(1):61-7. doi: 10.1016/0167-0115(95)00122-4. PMID: 8747785.

3) Metabolic control after canine islet transplantation. M.P.M. van der Burg, P.T.R. van Suylichem, O.R. Guicherit, J.H.M. van Deijnen, M. Frölich, and H.G. Gooszen (Universities of Leiden & Groningen, The Netherlands). Poster presented at the 13th Workshop of the AIDSPIT Study Group , Igls, Austria, January 23–25, 1994 •

4) Metabolic control after canine islet transplantation. Van der Burg M.P.M., Guicherit O.R., van Suylichem P.T.R., Frölich M., van Deijnen J.H.M. , Gooszen H.G. (Leiden, The Netherlands; Groningen, The Netherlands). Horm metab Res 1994; 26: 63. (Abstract). View/Download file 1MEMO_20251113_2

5) Background of this work was posted in Dutch Islets Transplant Team • @1MEMO 20250125 • URL https://michelvanderburg.com/2025/01/25/dutch-islets-transplant-team-1memo-20250125/

6) Michael P.M. van der Burg. Pancreatic islet transplantation: studies on the technique and efficacy of islet isolation and transplantation. (Doctoral Thesis, Faculty of Medicine, Leiden University Medical Center (LUMC) , Leiden University), Boskoop: M.P.M. van der Burg | Miracles.Media (ISBN electronic, pdf, 9789080216402 ; ISBN print 9789080216419, 9080216410), 1994: 192 p. URL Thesis Repository Leiden University https://hdl.handle.net/1887/3486604

PM – Recording of the 13th AIDSPIT seminar on lessons from clinical islet transplantation was posted yesterday (7).

7) Clinical Islet Transplantation 13th AIDSPIT • @1MEMO 20251113 • URL https://michelvanderburg.com/2025/11/13/clinical-islet-transplantation-13th-aidspit-1memo-20251113/

#GLP1 #diabetes #islets #transplant #AIDSPIT

Updates

20251127 title updated – insert : AIDSPIT 1994

Citation info : GLP-1 blood sugar regulation in islet transplants • AIDSPIT 1994 • Michel van der Burg • Miracles.Media • @1MEMO 20251114 • TakeNode 810cc881-d084-4d2e-b252-d432918b1946 • URL https://michelvanderburg.com/2025/11/14

Optiprep For Human Islet Purification • Cell Transplant Society 1999 • @1MEMO 20250203

Optiprep For Human Islet Purification • Cell Transplant Society 1999 • Michel van der Burg • Miracles.Media • @1MEMO 20250203 • TakeNode bad757b8-674c-4371-938c-ac73287bc457

Poster (#57) presentation Michel van der Burg, Cell Transplant Society congress 1999 in Montreux, Switzerland (1,2)

Outcome of the first series of human islet purifications with the novel Iodixanol -UWS density gradient — developed in the Leiden Islet Laboratory of the LUMC — performed during my working visit April – May 1998 at the “fast track” center of the Diabetes Research Institute (Scientific director Prof. C. Ricordi, MD) of the University of Miami (Miami, FL, USA).

Notes

1) Van der Burg MPM, Ranuncoli A, Molano R, Kirlew T, Ringers J, Bouwman E, Terpstra OT, Ricordi C. Optiprep for human islet purification. 4th International congress of the Cell Transplant Society, Montreux (Switzerland) March 21–24, 1999 .

2) Van der Burg MPM, Ranuncoli A, Molano R, Kirlew T, Ringers J, Bouwman E, Terpstra OT, Ricordi C. Optiprep for human islet purification (Abstract). Cell Transplant 1999; 8: 184. Download abstract below 1MEMO_20250202_3

Citation info : Optiprep For Human Islet Purification • Cell Transplant Society 1999 • Michel van der Burg • Miracles.Media • @1MEMO 20250203 • URL michelvanderburg.com/2025/02/03/

Fresh vs Cultured Pig Islets for Xenografts • NTV Bootcongres 1998 • @1MEMO 20250201

Fresh vs Cultured Pig Islets for Xenografts • NTV Bootcongres 1998 • Michel van der Burg • Miracles.Media • @1MEMO 20250201_1 • TakeNode 71d39e7e-ab5e-42b6-8cf2-a17d464ce132


Van der Burg MPM, Rijkelijkhuizen JKRA, Zwaan RP, Bouwman E. Culture of isolated pig islets pre-xenotransplantation greatly improves the quality and survival of the graft (Kweek van geïsoleerde varkenseilandjes pre-xenotransplantatie verbetert aanzienlijk de kwaliteit en overleving van het transplantaat). Tenth Congress of the Dutch Transplantation Society (Bootcongres 1998), Kerkrade (The Netherlands) April 21–23, 1998.

Download (pdf) NTV bulletin (abstract) & poster , file 1MEMO_20250201

EN – Abstract

PRE-TRANSPLANT SHORT-TERM CULTURE OF ISOLATED PIG ISLETS MARKEDLY IMPROVES THE QUALITY AND SURVIVAL OF THE XENOGRAFT
Van der Burg MPM,* Rijkelijkhuizen JKRA, Zwaan RP, and Bouwman E, Leiden University Medical Centre, Leiden, The Netherlands.

Pre-transplant culture of isolated islets reduces the graft’s immunogenicity in various models. Little is known, however, on the effect of culture in pig islet xenotransplantation — probably, because porcine islets have been found difficult to culture. Because pilot transplants of freshly-isolated pig islets in strongly immunosuppressed rats resulted in primary non function, we first studied 1-7 day culture of the isolated pig islets at 37°C in RPMI plus 10% porcine serum. Islets were isolated from large sows (n =6) by an improved method, resulting in intact islets (size 185±16 µm) and no loss during purification, yielding 2448 islets (IEQs)/g with a >95% purity and 90±2% viability as assessed by acridine orange – propidium iodide (AOPI) staining. During culture, however, islet recovery was 24±9% at day 1 and 17±6% at day 7 (NS vs day 1). In order to delineate whether the culture conditions or the quality of freshly isolated islets caused the islet loss during culture, we compared graft survival in nude mice at 1 mo after transplantation under the kidney capsule of ~2500 fresh islets in normoglycemic recipients or ~1000 cultured islets in STZ-diabetic (>20 mM) recipients. After transplanting fresh islets, histology of the kidneys — sectioned every 500 µm — demonstrated substantial scarring and (near-)absence of islets. Cultured islet transplants, by contrast, rendered 5/6 recipients normoglycemic, and showed a substantial mass of well-preserved islets with little scarring at the grafts’ site. Thus, viability by AOPI-staining of fresh islets poorly predicts the survival in vivo and in vitro. A non-immune mediated disintegration of part of the fresh islets may substantially reduce the functional capacity of the graft, both direct by lowering the effective islet dose, and indirect first because scarring may hamper the engraftment of viable tissue, and second because the cellular debris most probably will attract macrophages and induce the release of harmful cytokines.

Citation info : Fresh vs Cultured Pig Islets for Xenografts • NTV Bootcongres 1998 • Michel van der Burg • Miracles.Media • @1MEMO 20250201 • URL michelvanderburg.com/2025/02/01/

Purification Islets in Iodixanol-UWS • Leiden Start 1996 • @1MEMO 20250126

Purification Islets in Iodixanol-UWS • Leiden Start 1996 • Michel van der Burg • Miracles.Media • @1MEMO 20250126_1 • TakeNode c2a26daf-2c4f-4051-931d-16babc872c82

August 1995, I started designing the clinical promising islet purification solution of Iodixanal in UW-Solution (UWS). I mixed Optiprep – a 60 % solution of iodixanol in water – with a 2-times concentrated UWS, to prepare this density gradient solution. The first standard operation procedure of this Iodixanol-UWS gradient for our pig islet isolation research was completed November 1995.


This purification solution was a logical follow-up of our highly succesful Percoll-UWS density gradient — a similar solution of impermeants (that do not readily enter cells) with similar osmolarity (close to that of the tissue) , more practical though, and with the important advantage that iodixanol is clinical tested.
The Leiden Islet Lab had just moved into the Surgery Lab of the new LUMC building, and the islet team had grown, focussing on xenotransplantation. With more people isolating pig islets, more convenient solutions were tried.

Both Percoll-UWS and and the more convenient Histopaque-UWS were being used from 1992 for small scale islet isolations from juvenile pig pancreases.

July 1996, I introduced the Optiprep-UWS gradient to replace our Percoll-UWS gradient for larger scale porcine islet isolations , in comparison with the Histopaque gradient.

This work was first presented September 1997, both in this poster presented at the Xenotransplantation Congress in Nantes (France) and later that month also in a talk at the 6th Congress of the International Pancreas and Islet Transplant Association (IPITA) in Milan (Italy) — presentations that will be online at this site soon.

Notes

Van der Burg MPM, Basir I, Bouwman E. Non-traumatic porcine islet density gradient
purification in a novel iodixanol in University of Wisconsin solution. The 4th Int. Congress for Xenotransplantation, Nantes (France) Sept. 7–11, 1997.

Update 20250128 – update intro design timeline

Citation info : Purification Islets in Iodixanol-UWS • Leiden Start 1996 • Michel van der Burg • Miracles.Media • @1MEMO 20250126 • URL michelvanderburg.com/2025/01/26/

Entero Insular Axis • @1MEMO 20250123

Gastro-Entero-Pancreatic-System • Michel van der Burg • Miracles.Media • @1MEMO 20250123_1 • TakeNode 5b4fa0c5-cecb-45ba-aa39-6df4c833ed43

My first slide in the January 1988 Workshop of the Dutch Diabetes Research Society* in Oosterbeek, Holland, on our new Pancreas & Islet Transplantation Program that had just started in 1988, introduced this still undeveloped field of research the Gastro-Entero-Pancreatic-System (1).

This system ( GEPS ) in which the gastro-intestinal hormones influence the secretion of insulin and other hormones from the pancreatic islets – the “entero-insular” axis – is changed in transplantation of the pancreas or isolated islets of Langerhans.

Insulin feedback on the gut hormone CCK • Michel van der Burg • Miracles.Media • @1MEMO 20250123_2 • TakeNode ac392976-fa14-4d1e-95bb-84e5808ee443

Evidence of insulin feedback on the gut hormone CCK was presented with this poster the next year at the Holland Digestive Disease Week congress in the RAI in Amsterdam (2).

Notes

1) Workshop of the Dutch Diabetes Research Society*, Oosterbeek (The Netherlands) January 22–23, 1988.

2) Van der Burg MPM, Guicherit OR, Gooszen HG, Jansen JBMJ, Frölich M, Lamers CBHW. Evidence for insulin-feedback on fasting CCK in dogs. Holland Digestive Disease Week, Amsterdam (The Netherlands) June 21–24, 1989.

* NVDO – now known as : Dutch Association for Diabetes Research – https://www.nvdo.online/en/homepage-english/
Award – The year before I received the Dutch Diabetes Research Society 1987 Master’s
thesis award for my master’s thesis “Effect of cyclosporine-A on the endocrine pancreas”
(received at the Spring meeting of the Dutch Diabetes Research Society, Utrecht, The Netherlands, April 4, 1987).

Update 20250124 – added NVDO details and 1987 award master’s thesis “Effect of cyclosporine-A on the endocrine pancreas”

Citation info : Entero Insular Axis • Michel van der Burg • Miracles.Media • @1MEMO 20250123 • URL michelvanderburg.com/2025/01/23/