Delta-Cell Area is Unchanged in Human Pregnancy: Evidence From Immunohistochemistry.

AIM: Pancreatic islet δ-cells produce somatostatin, a paracrine regulator of insulin and glucagon secretion within islets. Although adaptive changes in α- and β-cell populations during pregnancy have been described in both animals and humans, data on δ-cell plasticity are sparse and entirely lacking in human pregnancy. We aimed to determine whether pancreatic islet δ-cell mass undergoes morphological adaptation during human pregnancy. METHODS AND RESULTS: Formalin-fixed paraffin-embedded pancreatic tissue from pregnant (n = 7) and non-pregnant (n = 7) donors was analysed. Sections were immunolabelled for somatostatin to identify δ cells, and whole-slide quantitative analysis was performed using an unbiased automated imaging pipeline. δ-cell area was measured across the entire pancreatic sections and compared between groups. In contrast to previously reported expansion of α- and β-cell populations in pregnancy, δ-cell area was not significantly different between pregnant and non-pregnant donors. No quantitative architectural alterations in δ-cell distribution within islets were observed. CONCLUSION: Pancreatic δ-cell area does not increase during human pregnancy. These findings demonstrate that endocrine cell plasticity within the maternal pancreas is selective and does not uniformly involve all islet cell subtypes.