Difference in the frequency of pouchitis between ulcerative colitis and familial adenomatous polyposis: is the explanation in peripouch fat?

AIM

Patients with ulcerative colitis (UC) have an unexplained higher incidence of pouchitis and a greater amount of peripouch fat compared with patients with familial adenomatous polyposis (FAP). The aims of this study were to compare the peripouch fat areas between patients with UC and patients with FAP, and to explore relationship between peripouch fat and pouchitis or chronic antibiotic-refractory pouchitis (CARP).

METHOD

Patients with an abdominal CT image from our prospectively maintained Pouch Database were included. Abdominal fat and peripouch fat were measured on CT images at different levels or planes. Comparisons of peripouch fat and CARP were performed before and after propensity score matching.

RESULTS

A total of 277 patients with UC and 40 patients with FAP were included. Compared with patients with FAP, patients with UC were found to have a higher incidence of pouchitis (58.5% vs 15.0%, P < 0.001) and CARP (24.5% vs 2.5%, P = 0.002) and a higher total peripouch fat area (P = 0.030) and mesenteric peripouch fat area (P = 0.022) at Level-3. Univariate and multivariate analyses showed that diagnosis (UC vs FAP) and peripouch fat areas at Level-3 and Level-5 were independent risk factors for CARP. With propensity score matching, 38 pairs of patients with UC and FAP were matched successfully. After matching, patients with UC were found to have higher total peripouch fat area and higher mesenteric peripouch fat area at Level-3, and a higher incidence of pouchitis (57.9% vs 13.2%, P < 0.001) and CARP (23.7% vs 2.6%, P = 0.007).

CONCLUSION

Our study demonstrates that patients with UC have more peripouch fat than those with FAP, which may explain the difference in the frequency of pouchitis and CARP between these groups of patients.

Intrapancreatic fat deposition and visceral fat volume are associated with the presence of diabetes after acute pancreatitis

Ectopic fat and abdominal adiposity phenotypes have never been studied holistically in individuals after acute pancreatitis (AP). The aim of the study was to investigate phenotypical differences in ectopic fat and abdominal fat between individuals after AP (with and without diabetes) and to determine the role of pancreatitis-related factors. Eighty-four individuals were studied cross-sectionally after a median of 21.5 mo since last episode of AP and were categorized into "diabetes" and "no diabetes" groups. Twenty-eight healthy volunteers were also recruited. With the use of magnetic resonance imaging, intrapancreatic fat percentage, liver fat percentage, visceral fat volume (VFV), subcutaneous fat volume, and visceral-to-subcutaneous (V/S) fat volume ratio were quantified. Analysis of variance was used to investigate the differences in these phenotypes between the groups. All analyses were adjusted for age and sex. Linear regression analysis was used to investigate the association between pancreatitis-related factors and the studied phenotypes. Intrapancreatic fat percentage was significantly higher in the diabetes group (10.2 ± 1.2%) compared with the no diabetes (9.2 ± 1.7%) and healthy volunteers (7.9 ± 1.9%) groups (P < 0.001). VFV was significantly higher in the diabetes (2,715.3 ±1,077.6 cm³) compared with no diabetes (1,983.2 ± 1,092.4 cm³) and healthy volunteer (1,126.2 ± 740.4 cm³) groups (P < 0.001). V/S fat volume ratio was significantly higher in the diabetes (0.97 ± 0.27) compared with no diabetes (0.68 ± 0.42) and healthy volunteer (0.52 ± 0.34) groups (P = 0.001). Biliary AP was associated with significantly higher intrapancreatic fat percentage (β = 0.67; 95% CI, 0.01, 1.33; P = 0.047). C-reactive protein levels during hospitalization for AP were associated with significantly higher VFV (β = 3.32; 95% CI, 1.68, 4.96; P < 0.001). In conclusion, individuals with diabetes after AP have higher intrapancreatic fat percentage, VFV, and V/S fat volume ratio. Levels of C-reactive protein during AP are significantly associated with VFV, whereas biliary AP is significantly associated with intrapancreatic fat percentage. NEW & NOTEWORTHY Individuals with diabetes after acute pancreatitis have significantly higher intrapancreatic fat percentage and visceral fat volume compared with individuals without diabetes after acute pancreatitis and healthy controls. C-reactive protein levels during hospitalization for acute pancreatitis and biliary etiology of acute pancreatitis are associated with significantly larger visceral fat and pancreatic fat depots, respectively.

Active cushing syndrome patients have increased ectopic fat deposition and bone marrow fat content compared to cured patients and healthy subjects: a pilot 1H-MRS study

OBJECTIVE

Glucocorticoid excess is one of the most important causes of bone disorders. Bone marrow fat (BMF) has been identified as a l new mediator of bone metabolism. Cushing syndrome (CS), is a main regulator of adipose tissue distribution but its impact on BMF is unknown. The objective of the study was to evaluate the effect of chronic hypercortisolism on BMF.

DESIGN

This was a cross-sectional study. Seventeen active and seventeen cured ACTH-dependent CS patients along with seventeen controls (matched with the active group for age and sex) were included.

METHODS

the BMF content of the femoral neck and L3 vertebrae were measured by 1H-MRS on a 3-Tesla wide-bore magnet. BMD was evaluated in patients using dual-energy X-ray absorptiometry.

RESULTS

Active CS patients had higher BMF content both in the femur (82.5±2.6%) and vertebrae (70.1±5.1%) compared to the controls (70.8±3.6%, p=0.013 and 49.0±3.7% p=0.005, respectively). In cured CS patients (average remission time of 43 months), BMF content was not different from controls at both sites (72.3±2.9% (femur) and 46.7%±5.3% (L3)). BMF content was positively correlated with age, fasting plasma glucose, HbA1c, triglycerides and visceral adipose tissue in the whole cohort and negatively correlated with BMD values in the CS patients .

CONCLUSIONS

Accumulation of BMF is induced by hypercortisolism. In remission patients BMF reached values of controls. Further studies are needed to determine whether this increase in marrow adiposity in CS is associated with bone loss.

Calibration of a semi-automated segmenting method for quantification of adipose tissue compartments from magnetic resonance images of mice

OBJECTIVE

To use an automated water-suppressed magnetic resonance imaging (MRI) method to objectively assess adipose tissue (AT) volumes in whole body and specific regional body components (subcutaneous, thoracic and peritoneal) of obese and lean mice.

MATERIALS/METHODS

Water-suppressed MR images were obtained on a 7T, horizontal-bore MRI system in whole bodies (excluding head) of 26 week old male C57BL6J mice fed a control (10% kcal fat) or high-fat diet (60% kcal fat) for 20 weeks. Manual (outlined regions) versus automated (Gaussian fitting applied to threshold-weighted images) segmentation procedures were compared for whole body AT and regional AT volumes (i.e., subcutaneous, thoracic, and peritoneal). The AT automated segmentation method was compared to dual-energy X-ray (DXA) analysis.

RESULTS

The average AT volumes for whole body and individual compartments correlated well between the manual outlining and the automated methods (R2>0.77, p<0.05). Subcutaneous, peritoneal, and total body AT volumes were increased 2-3 fold and thoracic AT volume increased more than 5-fold in diet-induced obese mice versus controls (p<0.05). MRI and DXA-based method comparisons were highly correlative (R2=0.94, p<0.0001).

CONCLUSIONS

Automated AT segmentation of water-suppressed MRI data using a global Gaussian filtering algorithm resulted in a fairly accurate assessment of total and regional AT volumes in a pre-clinical mouse model of obesity.

Automated unsupervised multi-parametric classification of adipose tissue depots in skeletal muscle

PURPOSE

To introduce and validate an automated unsupervised multi-parametric method for segmentation of the subcutaneous fat and muscle regions to determine subcutaneous adipose tissue (SAT) and intermuscular adipose tissue (IMAT) areas based on data from a quantitative chemical shift-based water-fat separation approach.

MATERIALS AND METHODS

Unsupervised standard k-means clustering was used to define sets of similar features (k = 2) within the whole multi-modal image after the water-fat separation. The automated image processing chain was composed of three primary stages: tissue, muscle, and bone region segmentation. The algorithm was applied on calf and thigh datasets to compute SAT and IMAT areas and was compared with a manual segmentation.

RESULTS

The IMAT area using the automatic segmentation had excellent agreement with the IMAT area using the manual segmentation for all the cases in the thigh (R(2): 0.96) and for cases with up to moderate IMAT area in the calf (R(2): 0.92). The group with the highest grade of muscle fat infiltration in the calf had the highest error in the inner SAT contour calculation.

CONCLUSION

The proposed multi-parametric segmentation approach combined with quantitative water-fat imaging provides an accurate and reliable method for an automated calculation of the SAT and IMAT areas reducing considerably the total postprocessing time.