Hospital time prior to death and pancreas histopathology: implications for future studies

Abstract

Aims/hypothesis: Diabetes research studies routinely rely upon the use of tissue samples from human organ donors. It remains unclear whether the length of hospital stay prior to organ donation affects the presence of cells infiltrating the pancreas or the frequency of replicating beta cells.

Methods: To address this, 39 organ donors without diabetes were matched for age, sex, BMI and ethnicity in groups of three. Within each group, donors varied by length of hospital stay immediately prior to organ donation (<3 days, 3 to <6 days, or ≥6 days). Serial sections from tissue blocks in the pancreas head, body and tail regions were immunohistochemically double stained for insulin and CD45, CD68, or Ki67. Slides were electronically scanned and quantitatively analysed for cell positivity.

Results: No differences in CD45⁺, CD68⁺, insulin⁺, Ki67⁺ or Ki67⁺/insulin⁺ cell frequencies were found when donors were grouped according to duration of hospital stay. Likewise, no interactions were observed between hospitalisation group and pancreas region, age, or both; however, with Ki67 staining, cell frequencies were greater in the body vs the tail region of the pancreas (∆ 0.65 [unadjusted 95% CI 0.25, 1.04]; p = 0.002) from donors <12 year of age. Interestingly, frequencies were less in the body vs tail region of the pancreas for both CD45⁺ cells (∆ -0.91 [95% CI -1.71, -0.10]; p = 0.024) and insulin⁺ cells (∆ -0.72 [95% CI -1.10, -0.34]; p < 0.001).

Conclusions/interpretation: This study suggests that immune or replicating beta cell frequencies are not affected by the length of hospital stay prior to donor death in pancreases used for research.

Data availability: All referenced macros (adopted and developed), calculations, programming code and numerical dataset files (including individual-level donor data) are freely available on GitHub through Zenodo at https://doi.org/10.5281/zenodo.1034422.

Keywords: Basic science; Clinical science; Human; Imaging (MRI/PET/other); Islets; Islets(all); Pathophysiology/metabolism.

Fig. 1

Cell staining by hospitalisation group and pancreas region. The percentages of cells that stained positive for CD45, CD68, insulin and Ki67 and dual positive for Ki67 + insulin (I) are shown. Data from the head, body and tail regions of the pancreas are based on least-square mean values taken from the ANOVA model; overall numbers represent grand mean values. p>0.05 for all comparisons (see ESM Table 2)

Fig. 2

Differences in CD45⁺ cells by pancreas region. (a) Percentage of CD45⁺ cells in the head, body and tail region of the pancreas. The middle 50% of the data and the 5th and 95th percentiles are shown by the box and whiskers, respectively; the circles outside the whiskers represent outliers. Dark grey circles and lines within the box represent mean and median values, respectively. (b) Point estimates of the least-squares mean differences between pancreas regions are represented by solid circles. Length of line was determined using an adjusted 95% CI. Comparisons of the head vs tail and body vs tail were found to be statistically significant (see main text for details).