Serum 25‐hydroxyvitamin D, vitamin D receptor, and vitamin D binding protein concentrations in dogs with acute pancreatitis compared to healthy control dogs

Abstract

BackgroundPrevious studies have documented vitamin D imbalance in dogs with acute pancreatitis (AP), but no studies have investigated serum vitamin D receptor (VDR) and vitamin D‐binding protein (VDBP) concentrations.ObjectivesCompare serum 25‐hydroxyvitamin D (25[OH]D), VDR, and VDBP concentrations in healthy dogs and dogs with AP and identify correlations between these concentrations with ionized calcium, C‐reactive protein (CRP), and canine‐specific pancreatic lipase (Spec cPL) concentrations.AnimalsTwenty‐two dogs with AP and 20 healthy control dogs.MethodsProspective cross‐sectional study. Serum 25(OH)D concentrations were measured using a chemiluminescence immunoassay, and VDR and VDBP concentrations were measured using a ELISA kit designed for dogs.ResultsSerum concentrations of 25(OH)D were lower in dogs with AP (mean ± SD, 66.1 ± 39.2 ng/mL) than in controls (96.8 ± 30.4 ng/mL; P = .01), and VDR concentrations were lower in dogs with AP (5.3 ± 3.5 ng/mL) than in controls (7.4 ± 2.5 ng/mL; P = .03). No difference was observed in serum VDBP concentrations between the groups. Serum VDR concentrations differed between survivors (median [interquartile range] = 6.6 [4.3‐8.2] ng/mL) and nonsurvivors (2.7 [0.5‐3.5] ng/mL; P = .01). Negative correlations were observed among serum VDR, CRP (rs = −0.55), and Spec cPL (rs = −0.47) concentrations in dogs with AP.Conclusions and Clinical ImportanceDogs with AP had lower serum 25(OH)D and VDR concentrations than controls. Additionally, our study suggests a potential role of VDR expression in the inflammatory process of AP in dogs.

Expression of vitamin D receptor, CYP24A1, and CYP27B1 in normal and inflamed canine pancreases

“…VDR expression is regulated transcriptionally by various molecules, including 1,25(OH) 2 D, parathyroid hormone, and fibroblast growth factor 23 ( 29 , 30 ), and differentially regulated in each tissue; for example, treatment with 1,25(OH) 2 D enhanced the VDR expression in kidneys but not in the intestine ( 30 ). Although the circulating levels of 1,25(OH) 2 D in dogs with pancreatitis were not determined, a decreased 25(OH)D concentration was reported in dogs with pancreatitis ( 15 , 31 ) and might have negatively regulated VDR transcription in inflamed pancreases. It is unclear whether the VDR transcription in the island of Langerhans is more affected than that in the pancreatic ducts and acini by various factors such as 1,25(OH) 2 D. Further studies on the effect of circulating 1,25(OH) 2 D levels on VDR expression in each part of the pancreas (ducts, acini, and islets of Langerhans) would be beneficial to identify the pathophysiology of VDR disruption in inflamed canine pancreases.…”

“…A previous study showed that the serum VDR concentration is decreased in dogs with acute pancreatitis; however, it was unclear which organs contributed to the low serum VDR concentration ( 15 ). Although the present study included only pancreatic tissues and not others where VDR is highly expressed, such as the kidneys and gastrointestinal tract ( 25–27 ), it was shown that VDR expression was decreased in the inflamed pancreatic tissue, supporting that this could contribute to the low serum VDR concentrations in dogs with pancreatitis.…”

“…It is unknown whether the VDR present in endocrine islets could affect inflammatory cells to cause pancreatitis because research on its effect on inflammation has usually been limited to in vitro studies. However, considering a previous study of dogs with acute pancreatitis showing that a lower serum VDR concentration is associated with a higher serum inflammatory biomarker ( 15 ), it can be proposed that the disrupted VDR expression in inflamed pancreatic tissue could contribute to aggravating inflammation.…”

“…Previous studies revealed that the VDR is expressed in the canine pancreas ( 14 ) and serum VDR concentrations decreased in dogs with acute pancreatitis ( 15 ). These findings suggest that pancreatitis could possibly be linked to changes in VDR expression in canine pancreatic tissues; however, no studies have investigated VDR expression in inflamed canine pancreases.…”