Magnetic resonance imaging: Proton density fat fraction for assessment of pancreatic fatty infiltration during progression of T2DM bama minipigs

Abstract

Background Recent studies have highlighted the correlation between diabetes and pancreatic fat infiltration. However, pancreatic fat content (PFC) is rarely confirmed by pathological results, and a change of PFC during progression of type 2 diabetes (T2DM) is currently controversial. Purpose To evaluate the relationship of MRI‐pancreatic proton density fat fraction to serologic changes and histology in an experimental model of diabetes. Study Type Prospective animal study. Animal Model Thirteen Bama pigs were randomly assigned to diabetes (n = 7) or control (n = 6) groups. Pigs in the diabetic group received high‐fat/high‐sugar feed, combined with three doses of streptozotocin injections. Field Strength/Sequence 3.0T, IDEAL‐IQ sequence. Assessment Starting in the fifth month, biochemical changes were evaluated; all pigs underwent axial MRI with the IDEAL‐IQ sequence to measured pancreatic fat fraction (PFF). PFC was measured by the Soxhlet extraction method. Pancreatic fat distribution and pancreas islet morphology were observed by histopathology. Statistical Tests A Mann–Whitney U‐test, independent‐samples t‐test, Pearson correlation, Spearman correlation, single‐measure intraclass correlation coefficient (ICC) were performed. Results During the development of T2DM, the PFF, weight, fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TCHO), low‐density lipoprotein (LDL), and HOMA‐IR (insulin resistance) of the experimental group showed an upward trend; fasting insulin (INS), high‐density lipoprotein (HDL), and HOMA‐β showed decreasing trends. At the end of the fifteenth month, FBG (mmol/L) was 18.06 ± 6.03 and 5.06 ± 1.41 (P < 0.001), PFF (%) was 36.52 ± 4.07 and 27.75 ± 3.73 (P = 0.002), INS (mU/L) was 21.59 ± 2.93 and 29.32 ± 3.27 (P = 0.001), HOMA‐IR was 16.83 ± 4.22 and 6.70 ± 2.45 (P < 0.001), HOMA‐β was 1.50 ± 0.24 and 2.77 ± 0.45 (P < 0.001), between the experimental and control groups. There were strong and moderate positive correlations between PFF and PFC (r = 0.968, P < 0.001), and FBG (r = 0.657, P = 0.015), and HOMA‐IR (r = 0.608, P = 0.028). Data Conclusion MRI‐proton density fat fraction can measure the fat content of the pancreas with great accuracy and repeatability; PFF is a potential biomarker that can reflect the different stages of diabetes development. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1905–1913.

Low thigh muscle strength in relation to myosteatosis in patients with type 2 diabetes mellitus

“…(2) Moderate-intensity activity, 600-1500 MET-min/week. The inclusion criteria of healthy control subjects without T2DM were as follows: (1) No history of T2DM, no T2DM-related clinical manifestations and normal fasting blood glucose. (2) Moderate-intensity activity.…”

“…Diabetes mellitus has become the third most common non-communicable disease threatening human health globally, following only cardiovascular disease and cancer 1 . Type 2 diabetes mellitus (T2DM) is the most common type of diabetes, accounting for around 90% of all diabetes patients 2 .…”

Resolving the omega‐3 methyl resonance with long echo time magnetic resonance spectroscopy in mouse adipose tissue at 9.4 T

“…Levels of fat unsaturation in body tissues have shown relevance in disease. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Including ω-3 fatty acid contributions to fat composition analysis is worthwhile because ω-3 dietary fat intake in humans has been demonstrated to correlate inversely to disease, [20][21][22][23][24][25] as have levels of adipose tissue ω-3 content. 8,9,28,29 Measuring ω-3 fatty acid content with in vivo MRS even at high field is challenging because of its low concentration in adipose tissue 43 and because of spectral overlap between the ω-3 and non-ω-3 methyl resonances 44 using standard short-TE techniques.…”

“…Levels of fat unsaturation in body tissues have shown relevance in disease 1–19 . Including ω‐3 fatty acid contributions to fat composition analysis is worthwhile because ω‐3 dietary fat intake in humans has been demonstrated to correlate inversely to disease, 20–25 as have levels of adipose tissue ω‐3 content 8,9,28,29 .…”

“…For example, lower levels of unsaturated fat in abdominal adipose tissue have been associated with obesity in humans 1,8,9 and in rodents 10,11 . Fat unsaturation levels have also been found altered in other diseases in various tissues in humans and in animals, 2–7,12–19 including breast cancer, 4,5,19 bone disease, 2,6,7,15,18 and diabetes 6,16 . Omega‐3 (ω‐3) dietary fat intake in humans is related inversely to disease, including obesity, 20,21 diabetes, 20,21 osteoporosis 22,23 and breast cancer 24,25 .…”