Beta-cell replication is increased in donor organs from young patients after prolonged life support

Abstract

Objective: This study assesses beta-cell replication in human donor organs and examines possible influences of the preterminal clinical conditions.

Research design and methods: beta-Cell replication was quantified in a consecutive series of n = 363 human organ donors using double immunohistochemistry for Ki67 and insulin. Uni- and multivariate analysis was used to correlate replication levels to clinical donor characteristics and histopathologic findings.

Results: beta-Cell replication was virtually absent in most donors, with < or =0.1% Ki67-positive beta-cells in 72% of donors. A subpopulation of donors, however, showed markedly elevated levels of replication of up to 7.0% Ki67-positive beta-cells. beta-Cell replication was accompanied by the increased replication of glucagon-, somatostatin-, and CA19.9-positive cells. Prolonged life support, kidney dysfunction, relatively young donor age, inflammatory infiltration, and prolonged brain death before organ retrieval were all found to be significantly associated with an increased level (> or =90th percentile) of beta-cell replication, with the first three risk factors being independent predictors. Increased beta-cell replication was most often noted in relatively young donors (< or =25 years) who received prolonged (> or =3 days) life support (68%); in contrast, it was rare in donors with a short duration of life support regardless of age (1%). Prolonged life support was accompanied by increased levels of CD68(+) and LCA/CD45(+) infiltration in the pancreatic parenchyma.

Conclusion: These results indicate that preterminal clinical conditions in (young) organ donors can lead to increased inflammatory infiltration of the pancreas and to increased beta-cell replication.

FIG. 1.

Imunohistochemical double staining for replication markers and pancreatic cell type–specific markers in paraffin sections of human donor pancreas. Donors with a relatively high level of β-cell replication (≥90th percentile) (high) show increased replication in endocrine and ductal cell types compared with donors with a low level of β-cell replication (<90th percentile) (low). Representative images are shown. Staining for Ki67 (brown) and insulin (red) shows replicating cells in and around islets of Langerhans (A and B; ×70); part of the replicating islet cells correspond to insulin-positive β-cells (C and D; blue arrows; ×200). Staining for the G₂ to M transition marker phosphohistone H3 (brown) and insulin (red) shows an immunopositive mitotic β-cell (E and F; blue arrow; ×200). Staining for the transcription factor Nkx6.1 (brown) and insulin (red) shows colocalization of the two markers (G and H; ×200). Staining for Ki67 (brown) and glucagon (red) shows replicating α-cells (I and J; blue arrows; ×200). Double staining for Ki67 (brown) and somatostatin (red) shows replicating δ-cells (K and L; blue arrows; ×200). Double staining for Ki67 (brown) and the panendocrine marker synaptophysin (red) shows replicating endocrine islet cells (M and N; ×200). Double labeling for Ki67 (brown) and the ductal marker CA19.9 (red) shows replicating ductal cells (O and P; blue arrow; ×200). (A high-quality digital representation of this figure is available in the online issue.)

FIG. 2.

Replication levels in insulin-positive β-cells (Ins+), glucagon-positive α-cells (Gluc+), somatostatin-positive δ-cells (Som+), and carbohydrate antigen 19.9–positive ductal cells (CA19.9+) as determined by double immunohistochemistry for Ki-67. Donors with a high level of β-cell replication (≥90th percentile; n = 36; ■) are compared with matched controls (<90th percentile; n = 36; □). Results are expressed as means ± SE; significance of difference with the control condition was calculated with a nonparametric Mann-Whitney U test: *P < 0.001; †P = 0.002; ‡P = 0.016.

FIG. 3.

Immunohistochemical staining for monocytic and leukocytic infiltration markers in paraffin sections of human donor pancreas. Donors with a relatively high level of β-cell replication (≥90th percentile) (high) have increased inflammatory infiltration compared with donors with low level of β-cell replication (<90th percentile) (low). Representative images are shown. Double staining for CD68 (brown) and the panendocrine marker synaptophysin (red) (A and B; ×70), LCA/CD45 (brown) and synaptophysin (red) (C and D; ×70), and CD3 (brown) and synaptophysin (red) (E and F; ×70). (A high-quality digital representation of this figure is available in the online issue.)