Significance of steatosis in pancreatic transplantation

Automated image analysis method to detect and quantify fat cell infiltration in hematoxylin and eosin stained human pancreas histology images

Fatty infiltration in pancreas leading to steatosis is a major risk factor in pancreas transplantation. Hematoxylin and eosin (H and E) is one of the common histological staining techniques that provides information on the tissue cytoarchitecture. Adipose (fat) cells accumulation in pancreas has been shown to impact beta cell survival, its endocrine function and pancreatic steatosis and can cause non-alcoholic fatty pancreas disease (NAFPD). The current automated tools (E.g. Adiposoft) available for fat analysis are suited for white fat tissue which is homogeneous and easier to segment unlike heterogeneous tissues such as pancreas where fat cells continue to play critical physiopathological functions. The currently, available pancreas segmentation tool focuses on endocrine islet segmentation based on cell nuclei detection for diagnosis of pancreatic cancer. In the current study, we present a fat quantifying tool, Fatquant, which identifies fat cells in heterogeneous H and E tissue sections with reference to diameter of fat cell. Using histological images from a public database, we observed an intersection over union of 0.797 to 0.962 and 0.675 to 0.937 for manual versus Fatquant analysis of pancreas and liver, respectively.

Hypertension, but not body mass index, is predictive of increased pancreatic lipid content and islet dysfunction

Pancreatic steatosis is thought to be a negative risk factor for pancreas transplant outcomes. Despite considering donor body mass index (BMI) and the visualization of intercalated fat as indicators of donor pancreas lipid content, transplant surgeons do not use a quantitative method to directly measure steatosis when deciding to transplant a pancreas. In this study, we used nondiabetic human pancreata donated for research to measure the pancreatic and islet-specific lipid content to determine which clinical markers correlate best with lipid content. Interestingly, we found that BMI and age correlate with increased pancreatic lipid content (Panc-LC) in men, but not women. Our findings further suggest that total Panc-LC correlates with an increase in islet lipid content for both men and women. We noted that pancreata donated from individuals with a history of hypertension have increased Panc-LC independent of donor BMI or sex. Moreover, we identify hypertension as a risk factor for reduced islet function after islet isolation. Together, our findings emphasize differences in pancreas graft quality related to pancreatic and islet lipid content, which may not be predicted by assessing BMI alone but may be influenced by a donor history of hypertension.

Quantification of pancreatic proton density fat fraction in diabetic pigs using MR imaging and IDEAL-IQ sequence

Background

Recent studies have highlighted the correlation between diabetes and pancreatic fat infiltration. Notably, pancreatic fat content (PFC) is a potential biomarker in diabetic patients, and magnetic resonance imaging (MRI) provides an effective method for noninvasive assessment of pancreatic fat infiltration. However, most reports of quantitative measurement of pancreatic fat have lacked comparisons of pathology results. The primary objective of this study was to determine the feasibility and accuracy of pancreatic MRI by using pancreatic fat fraction (PFF) measurements with the IDEAL-IQ sequence; the secondary objective was to explore changes in PFC between pigs with and without diabetes.

Methods

In this prospective study, 13 Bama Mini-pigs (7 females, 6 males; median age, 2 weeks) were randomly assigned to diabetes (n = 7) or control (n = 6) groups. Pigs in the diabetes group received high fat/high sugar feed, combined with streptozotocin injections. At the end of 15 months, biochemical changes were evaluated. All pigs underwent axial MRI with the IDEAL-IQ sequence to measure PFF; PFC of fresh pancreatic parenchyma was measured by the Soxhlet extraction method; and pancreatic fat distribution was observed by histopathology. Results of all analyses were compared between the diabetes and control groups by using the Mann-Whitney U-test. Correlations of PFF and PFC, fasting blood glucose (GLU), and serum insulin (INS) were calculated by using the Spearman correlation coefficient. Single-measure intraclass correlation coefficient (ICC) was used to assess interreader agreement.

Results

There were significant differences between diabetes and control groups: GLU (mmol/L) was 18.06 ± 6.03 and 5.06 ± 1.41 (P < 0.001); INS (mU/L) was 21.59 ± 2.93 and 29.32 ± 3.27 (P = 0.003); PFC (%) was 34.60 ± 3.52 and 28.63 ± 3.25 (P = 0.027); and PFF (%) was 36.51 ± 4.07 and 27.75 ± 3.73 (P = 0.003). There was a strongly positive correlation between PFF and PFC (r = 0.934, P < 0.001); there were moderate correlations between PFF and GLU (r = 0.736, P = 0.004; positive correlation), and between PFF and INS (r = − 0.747, P = 0.003; negative correlation). Excellent interreader agreement was observed for PFF measurements (ICC, 0.954).

Conclusions

Pancreatic fat infiltration shows a clear association with diabetes. MRI with the IDEAL-IQ sequence can be used to accurately and reproducibly quantify PFC.

Solid pancreas transplant: Pushing forward

Pancreas transplant has evolved significantly in recent years. It has now become a viable treatment option on type 1 diabetic patients with poorly controlled diabetes on conventional treatment, insulin intolerance, hypoglycaemia unawareness, brittle diabetes and/ or end-stage kidney disease. The purpose of this review is to provide an overview of pancreas transplant historical origins and current barriers to broader utilization of pancreata for transplant, with a focus on areas for future improvement to better pancreas transplant care. Donor pancreata remain underutilized; pancreatic allograft discard rates remain close to 30% in the United States. Donations after cardiac death (DCD) pancreata are seldom procured. Study groups from Europe and the United Kingdom showed that procurement professionalization and standardization of technique, as well as development of independent regional procurement teams might increase organ procurement efficiency, decrease discards and increase pancreatic allograft utilization. Pancreas transplant programs should consider exploring pancreas procurement opportunities on DCD and obese donors. Selected type 2 diabetics should be considered for pancreas transplant. Longer follow-up studies need to be performed in order to ascertain the long-term cardiovascular and quality of life benefits following pancreas transplant; the outcomes of which might eventually spearhead advocacy towards broader application of pancreas transplant among diabetics.