Characterization of porcine endogenous retrovirus expression in neonatal and adult pig pancreatic islets

Nizar I. Mourad, Claire Crossan, Victoria Cruikshank, Linda Scobie, Pierre Gianello

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Abstract

Background: Pig islets represent an alternative to the current modes of treatment for diabetic patients. However, the concerns over pathogen transmission including that of PERV limit their immediate, widespread usage in humans. It has been previously demonstrated that PERV copy number and particularly expression levels can vary considerably between individuals and within different tissues of a single animal. In general, expression levels have been found to be particularly low in the pancreas compared to other porcine tissues suggesting a reduced risk associated with the use of this tissue. Data regarding this crucial aspect however, remain limited and little is known about PERV status of islets themselves which represent the final product to be transplanted. In addition, comparative analysis of the PERV status of neonatal piglets with adults is important since they are increasingly considered as potential islet donors for xenotransplantation.
Methods: Tissue samples from 51 neonatal piglets (age between 14 and 21 days) and 29 adult pigs were collected from Belgian landrace pigs used for pancreas procurement and islet isolation. Tissue biopsies were used to extract DNA for PERV copy number quantification by qPCR and RNA for PERV expression by qRT-PCR.
Results: As expected, PERV expression demonstrated great variation and was significantly lower in pancreas compared to other tissues. More importantly, PERV RNA expression was found to be specifically enriched in pancreatic islets reaching values similar to those found in other tissues such as liver and kidney. Interestingly, this expression was not coupled with the detection of reverse transcriptase in islet cultures or indeed detection of PERV virus. Lung, spleen and lymph node consistently showed the highest levels of PERV expression. Comparison of PERV in neonatal and adult pigs showed that copy number did not vary significantly from birth to adulthood. PERV expression on the other hand, was significantly lower in neonatal pig islets compared to adult islets and did not increase over the period of culture.
Conclusion: Our study confirms the low level of PERV expression in whole pancreas in a large population of both neonatal and adult pigs (n=80). The level of PERV expression was however higher in the endocrine tissue than in the exocrine cells. There was no correlation between PERV status in donor PBMCs and islet cells, and no evidence of active replication in in vitro regardless of PERV expression in islet cells. Moreover, neonatal pig islets were found to have significantly lower PERV expression compared to adult islets. Neonatal islets have been suggested as the best choice for xenotransplantation in terms of economic and procurement considerations; the PERV status reported here would also potentially support their use.
Original languageEnglish
Article numbere12311
JournalXenotransplantation
Volume24
Issue number4
Early online date26 Apr 2017
DOIs
Publication statusPublished - Aug 2017

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Endogenous Retroviruses
Islets of Langerhans
Swine
Pancreas
Heterologous Transplantation
RNA
Infectious Disease Transmission
RNA-Directed DNA Polymerase
Spleen
Lymph Nodes
Economics
Tissue Donors
Parturition
Viruses
Kidney
Biopsy
Polymerase Chain Reaction
Lung
Liver
DNA

Keywords

  • porcine endogenous retrovirus
  • pancreatic islets
  • virology

Cite this

@article{ef16d9667a9a4a5cad395c80460bc54b,
title = "Characterization of porcine endogenous retrovirus expression in neonatal and adult pig pancreatic islets",
abstract = "Background: Pig islets represent an alternative to the current modes of treatment for diabetic patients. However, the concerns over pathogen transmission including that of PERV limit their immediate, widespread usage in humans. It has been previously demonstrated that PERV copy number and particularly expression levels can vary considerably between individuals and within different tissues of a single animal. In general, expression levels have been found to be particularly low in the pancreas compared to other porcine tissues suggesting a reduced risk associated with the use of this tissue. Data regarding this crucial aspect however, remain limited and little is known about PERV status of islets themselves which represent the final product to be transplanted. In addition, comparative analysis of the PERV status of neonatal piglets with adults is important since they are increasingly considered as potential islet donors for xenotransplantation.Methods: Tissue samples from 51 neonatal piglets (age between 14 and 21 days) and 29 adult pigs were collected from Belgian landrace pigs used for pancreas procurement and islet isolation. Tissue biopsies were used to extract DNA for PERV copy number quantification by qPCR and RNA for PERV expression by qRT-PCR. Results: As expected, PERV expression demonstrated great variation and was significantly lower in pancreas compared to other tissues. More importantly, PERV RNA expression was found to be specifically enriched in pancreatic islets reaching values similar to those found in other tissues such as liver and kidney. Interestingly, this expression was not coupled with the detection of reverse transcriptase in islet cultures or indeed detection of PERV virus. Lung, spleen and lymph node consistently showed the highest levels of PERV expression. Comparison of PERV in neonatal and adult pigs showed that copy number did not vary significantly from birth to adulthood. PERV expression on the other hand, was significantly lower in neonatal pig islets compared to adult islets and did not increase over the period of culture.Conclusion: Our study confirms the low level of PERV expression in whole pancreas in a large population of both neonatal and adult pigs (n=80). The level of PERV expression was however higher in the endocrine tissue than in the exocrine cells. There was no correlation between PERV status in donor PBMCs and islet cells, and no evidence of active replication in in vitro regardless of PERV expression in islet cells. Moreover, neonatal pig islets were found to have significantly lower PERV expression compared to adult islets. Neonatal islets have been suggested as the best choice for xenotransplantation in terms of economic and procurement considerations; the PERV status reported here would also potentially support their use.",
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Characterization of porcine endogenous retrovirus expression in neonatal and adult pig pancreatic islets. / Mourad, Nizar I.; Crossan, Claire; Cruikshank, Victoria; Scobie, Linda; Gianello, Pierre .

In: Xenotransplantation, Vol. 24, No. 4, e12311, 08.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Characterization of porcine endogenous retrovirus expression in neonatal and adult pig pancreatic islets

AU - Mourad, Nizar I.

AU - Crossan, Claire

AU - Cruikshank, Victoria

AU - Scobie, Linda

AU - Gianello, Pierre

N1 - Acceptance email in SAN Note: this is an OA article, replaced AAM with VoR - ET 15-5-17 Funded by Seventh Framework Programme. Grant Number: 601827 ‘’XENOISLET’’

PY - 2017/8

Y1 - 2017/8

N2 - Background: Pig islets represent an alternative to the current modes of treatment for diabetic patients. However, the concerns over pathogen transmission including that of PERV limit their immediate, widespread usage in humans. It has been previously demonstrated that PERV copy number and particularly expression levels can vary considerably between individuals and within different tissues of a single animal. In general, expression levels have been found to be particularly low in the pancreas compared to other porcine tissues suggesting a reduced risk associated with the use of this tissue. Data regarding this crucial aspect however, remain limited and little is known about PERV status of islets themselves which represent the final product to be transplanted. In addition, comparative analysis of the PERV status of neonatal piglets with adults is important since they are increasingly considered as potential islet donors for xenotransplantation.Methods: Tissue samples from 51 neonatal piglets (age between 14 and 21 days) and 29 adult pigs were collected from Belgian landrace pigs used for pancreas procurement and islet isolation. Tissue biopsies were used to extract DNA for PERV copy number quantification by qPCR and RNA for PERV expression by qRT-PCR. Results: As expected, PERV expression demonstrated great variation and was significantly lower in pancreas compared to other tissues. More importantly, PERV RNA expression was found to be specifically enriched in pancreatic islets reaching values similar to those found in other tissues such as liver and kidney. Interestingly, this expression was not coupled with the detection of reverse transcriptase in islet cultures or indeed detection of PERV virus. Lung, spleen and lymph node consistently showed the highest levels of PERV expression. Comparison of PERV in neonatal and adult pigs showed that copy number did not vary significantly from birth to adulthood. PERV expression on the other hand, was significantly lower in neonatal pig islets compared to adult islets and did not increase over the period of culture.Conclusion: Our study confirms the low level of PERV expression in whole pancreas in a large population of both neonatal and adult pigs (n=80). The level of PERV expression was however higher in the endocrine tissue than in the exocrine cells. There was no correlation between PERV status in donor PBMCs and islet cells, and no evidence of active replication in in vitro regardless of PERV expression in islet cells. Moreover, neonatal pig islets were found to have significantly lower PERV expression compared to adult islets. Neonatal islets have been suggested as the best choice for xenotransplantation in terms of economic and procurement considerations; the PERV status reported here would also potentially support their use.

AB - Background: Pig islets represent an alternative to the current modes of treatment for diabetic patients. However, the concerns over pathogen transmission including that of PERV limit their immediate, widespread usage in humans. It has been previously demonstrated that PERV copy number and particularly expression levels can vary considerably between individuals and within different tissues of a single animal. In general, expression levels have been found to be particularly low in the pancreas compared to other porcine tissues suggesting a reduced risk associated with the use of this tissue. Data regarding this crucial aspect however, remain limited and little is known about PERV status of islets themselves which represent the final product to be transplanted. In addition, comparative analysis of the PERV status of neonatal piglets with adults is important since they are increasingly considered as potential islet donors for xenotransplantation.Methods: Tissue samples from 51 neonatal piglets (age between 14 and 21 days) and 29 adult pigs were collected from Belgian landrace pigs used for pancreas procurement and islet isolation. Tissue biopsies were used to extract DNA for PERV copy number quantification by qPCR and RNA for PERV expression by qRT-PCR. Results: As expected, PERV expression demonstrated great variation and was significantly lower in pancreas compared to other tissues. More importantly, PERV RNA expression was found to be specifically enriched in pancreatic islets reaching values similar to those found in other tissues such as liver and kidney. Interestingly, this expression was not coupled with the detection of reverse transcriptase in islet cultures or indeed detection of PERV virus. Lung, spleen and lymph node consistently showed the highest levels of PERV expression. Comparison of PERV in neonatal and adult pigs showed that copy number did not vary significantly from birth to adulthood. PERV expression on the other hand, was significantly lower in neonatal pig islets compared to adult islets and did not increase over the period of culture.Conclusion: Our study confirms the low level of PERV expression in whole pancreas in a large population of both neonatal and adult pigs (n=80). The level of PERV expression was however higher in the endocrine tissue than in the exocrine cells. There was no correlation between PERV status in donor PBMCs and islet cells, and no evidence of active replication in in vitro regardless of PERV expression in islet cells. Moreover, neonatal pig islets were found to have significantly lower PERV expression compared to adult islets. Neonatal islets have been suggested as the best choice for xenotransplantation in terms of economic and procurement considerations; the PERV status reported here would also potentially support their use.

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KW - pancreatic islets

KW - virology

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M3 - Article

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JO - Xenotransplantation

JF - Xenotransplantation

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