Breath-hold 1H-magnetic resonance spectroscopy for intrahepatic lipid quantification at 3 Tesla

Glycaemic Response to a Nut-Enriched Diet in Asian Chinese Adults with Normal or High Glycaemia: The Tū Ora RCT

Nut-based products are a good source of high-quality plant protein in addition to mono- and polyunsaturated fatty acids, and may aid low-glycaemic dietary strategies important for the prevention of type 2 diabetes (T2D). In particular, they may be advantageous in populations susceptible to dysglycaemia, such as Asian Chinese. The present study aimed to compare effects of a higher-protein nut bar (HP-NB, also higher in total fibre and unsaturated fats, comprising mixed almonds and peanuts) vs. an isoenergetic higher-carbohydrate cereal bar (HC-CB) within the diet of 101 Chinese adults with overweight and normo- or hyperglycaemia. Ectopic pancreas and liver fat were characterised using magnetic resonance imaging and spectroscopy (MRI/S) as a secondary outcome. Participants were randomized to receive HP-NB or HC-CB daily as a 1 MJ light meal or snack replacement, in addition to healthy eating advice. Anthropometry and clinical indicators of T2D risk were assessed fasted and during an oral glucose tolerance test (OGTT), pre- and post-intervention. No significant difference was observed between diet groups for body weight, body mass index, waist or hip circumference, blood pressure, glucoregulatory markers, lipid profile or inflammatory markers over 12 weeks (all, p > 0.05). No difference was observed between glycaemic subgroups or those with normal versus high ectopic organ fat. Although HP-NB can attenuate postprandial glycaemia following a meal, no effects were observed for either fasting or glucose-mediated outcomes following longer-term inclusion in the habitual diet of Chinese adults with overweight, including at-risk subgroups.

Aspirin for Metabolic Dysfunction-Associated Steatotic Liver Disease Without Cirrhosis: A Randomized Clinical Trial

Importance

Aspirin may reduce severity of metabolic dysfunction-associated steatotic liver disease (MASLD) and lower the incidence of end-stage liver disease and hepatocellular carcinoma, in patients with MASLD. However, the effect of aspirin on MASLD is unknown.

Objective

To test whether low-dose aspirin reduces liver fat content, compared with placebo, in adults with MASLD.

Design, Setting, and Participants

This 6-month, phase 2, randomized, double-blind, placebo-controlled clinical trial was conducted at a single hospital in Boston, Massachusetts. Participants were aged 18 to 70 years with established MASLD without cirrhosis. Enrollment occurred between August 20, 2019, and July 19, 2022, with final follow-up on February 23, 2023.

Interventions

Participants were randomized (1:1) to receive either once-daily aspirin, 81 mg (n = 40) or identical placebo pills (n = 40) for 6 months.

Main Outcomes and Measures

The primary end point was mean absolute change in hepatic fat content, measured by proton magnetic resonance spectroscopy (MRS) at 6-month follow-up. The 4 key secondary outcomes included mean percentage change in hepatic fat content by MRS, the proportion achieving at least 30% reduction in hepatic fat, and the mean absolute and relative reductions in hepatic fat content, measured by magnetic resonance imaging proton density fat fraction (MRI-PDFF). Analyses adjusted for the baseline value of the corresponding outcome. Minimal clinically important differences for study outcomes were not prespecified.

Results

Among 80 randomized participants (mean age, 48 years; 44 [55%] women; mean hepatic fat content, 35% [indicating moderate steatosis]), 71 (89%) completed 6-month follow-up. The mean absolute change in hepatic fat content by MRS was -6.6% with aspirin vs 3.6% with placebo (difference, -10.2% [95% CI, -27.7% to -2.6%]; P = .009). Compared with placebo, aspirin treatment significantly reduced relative hepatic fat content (-8.8 vs 30.0 percentage points; mean difference, -38.8 percentage points [95% CI, -66.7 to -10.8]; P = .007), increased the proportion of patients with 30% or greater relative reduction in hepatic fat (42.5% vs 12.5%; mean difference, 30.0% [95% CI, 11.6% to 48.4%]; P = .006), reduced absolute hepatic fat content by MRI-PDFF (-2.7% vs 0.9%; mean difference, -3.7% [95% CI, -6.1% to -1.2%]; P = .004]), and reduced relative hepatic fat content by MRI-PDFF (-11.7 vs 15.7 percentage points; mean difference, -27.3 percentage points [95% CI, -45.2 to -9.4]; P = .003). Thirteen participants (32.5%) in each group experienced an adverse event, most commonly upper respiratory tract infections (10.0% in each group) or arthralgias (5.0% for aspirin vs 7.5% for placebo). One participant randomized to aspirin (2.5%) experienced drug-related heartburn.

Conclusions and Relevance

In this preliminary randomized clinical trial of patients with MASLD, 6 months of daily low-dose aspirin significantly reduced hepatic fat quantity compared with placebo. Further study in a larger sample size is necessary to confirm these findings.

Trial Registration

ClinicalTrials.gov Identifier: NCT04031729.

Breast adipose tissue attenuation as a novel imaging biomarker for cardiometabolic risk

BACKGROUND

Certain adipose tissue depots infer higher cardiometabolic risk than body mass index (BMI).

PURPOSE

To assess breast adipose tissue (BrAT) attenuation as a novel imaging biomarker for cardiometabolic risk.

MATERIAL AND METHODS

We studied 151 women (mean age = 56 ± 1 years) across the weight spectrum. BrAT attenuation, abdominal adipose tissue cross-sectional areas (CSA), and attenuation were quantified using non-contrast computed tomography (CT) scans. Cardiometabolic risk factors were assessed from medical records.

RESULTS

BrAT attenuation was lower in obese women compared to lean women. BrAT attenuation was inversely associated with BMI, waist circumference, abdominal fat CSA, fasting glucose, and triglycerides (P ≤ 0.02), and positively associated with abdominal adipose tissue attenuation (P < 0.001). BrAT attenuation had a sensitivity of 90% but a specificity of only 35% in detecting the metabolic syndrome (area under the curve = 0.63).

CONCLUSION

BrAT attenuation is associated with cardiometabolic risk markers and could serve as an imaging biomarker for opportunistic risk assessment in patients undergoing CT examination of the chest.

Growth Hormone Administration Improves Nonalcoholic Fatty Liver Disease in Overweight/Obesity: A Randomized Trial

CONTEXT

Overweight and obesity are associated with relative growth hormone (GH) deficiency, which has been implicated in the development of nonalcoholic fatty liver disease (NAFLD). NAFLD is a progressive disease without effective treatments.

OBJECTIVE

We hypothesized that GH administration would reduce hepatic steatosis in individuals with overweight/obesity and NAFLD.

METHODS

In this 6-month randomized, double-blind, placebo-controlled trial of low-dose GH administration, 53 adults aged 18 to 65 years with BMI ≥25 kg/m2 and NAFLD without diabetes were randomized to daily subcutaneous GH or placebo, targeting insulin-like growth factor 1 (IGF-1) to the upper normal quartile. The primary endpoint was intrahepatic lipid content (IHL) by proton magnetic resonance spectroscopy (1H-MRS) assessed before treatment and at 6 months.

RESULTS

Subjects were randomly assigned to a treatment group (27 GH; 26 placebo), with 41 completers (20 GH and 21 placebo) at 6 months. Reduction in absolute % IHL by 1H-MRS was significantly greater in the GH vs placebo group (mean ± SD: -5.2 ± 10.5% vs 3.8 ± 6.9%; P = .009), resulting in a net mean treatment effect of -8.9% (95% CI, -14.5 to -3.3%). All side effects were similar between groups, except for non-clinically significant lower extremity edema, which was more frequent in the GH vs placebo group (21% vs 0%, P = .02). There were no study discontinuations due to worsening of glycemic status, and there were no significant differences in change in glycemic measures or insulin resistance between the GH and placebo groups.

CONCLUSION

GH administration reduces hepatic steatosis in adults with overweight/obesity and NAFLD without worsening glycemic measures. The GH/IGF-1 axis may lead to future therapeutic targets for NAFLD.

Ectopic lipid deposition in muscle and liver, quantified by proton magnetic resonance spectroscopy

Advances in the development of noninvasive imaging techniques have spurred investigations into ectopic lipid deposition in the liver and muscle and its implications in the development of metabolic diseases such as type 2 diabetes. Computed tomography and ultrasound have been applied in the past, though magnetic resonance-based methods are currently considered the gold standard as they allow more accurate quantitative detection of ectopic lipid stores. This review focuses on methodological considerations of magnetic resonance-based methods to image hepatic and muscle fat fractions, and it emphasizes anatomical and morphological aspects and how these may influence data acquisition, analysis, and interpretation.

CT Texture Analysis in Nonalcoholic Fatty Liver Disease (NAFLD)

Background

Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease worldwide. There are limited biomarkers that can detect progression from simple steatosis to nonalcoholic steatohepatitis (NASH). The purpose of our study was to utilize CT texture analysis to distinguish steatosis from NASH.

Methods

16 patients with NAFLD (38% male, median (interquartile range): age 57 (48-64) years, BMI 37.5 (35.0-46.8) kg/m2) underwent liver biopsy and abdominal non-contrast CT. CT texture analysis was performed to quantify gray-level tissue summaries (e.g., entropy, kurtosis, skewness, and attenuation) using commercially available software (TexRad, Cambridge England). Logistic regression analyses were performed to quantify the association between steatosis/NASH status and CT texture. ROC curve analysis was performed to determine sensitivity, specificity, AUC, 95% CIs, and cutoff values of texture parameters to differentiate steatosis from NASH.

Results

By histology, 6/16 (37%) of patients had simple steatosis and 10/16 (63%) had NASH. Patients with NASH had lower entropy (median, interquartile range (IQR): 4.3 (4.1, 4.8) vs. 5.0 (4.9, 5.2), P = 0.013) and lower mean value of positive pixels (MPP) (34.4 (21.8, 52.2) vs. 66.5 (57.0, 70.7), P = 0.009) than those with simple steatosis. Entropy values below 4.73 predict NASH with 100% (95%CI: 67-100%) specificity and 80% (50-100%) sensitivity, AUC: 0.88. MPP values below 54.0 predict NASH with 100% (67-100%) specificity and 100% (50-100%) sensitivity, AUC 0.90.

Conclusion

Our study provides preliminary evidence that CT texture analysis may serve as a novel imaging biomarker for disease activity in NAFLD and the discrimination of steatosis and NASH.

Magnetic Resonance Imaging to Assess Body Composition Change in Adolescents With Obesity After Sleeve Gastrectomy

OBJECTIVES

Metabolic and bariatric surgery is the most effective weight loss treatment for severe obesity. The number of adolescents undergoing sleeve gastrectomy is increasing. We investigated changes in body composition in adolescents undergoing sleeve gastrectomy 12-26 weeks post-operatively using whole-body magnetic resonance imaging (WB-MRI).

METHODS

This prospective cohort study assessed changes in adipose tissue compartments (ie, visceral, subcutaneous, and intermuscular) and muscle in 18 obese adolescents, ages 14-19, 89% female, with body mass index z -score of 2.6 ± 0.25 (range 2.16-3.2). All underwent WB-MRI 1.5-17 weeks pre-operatively and 12-26 weeks post-operatively.

RESULTS

Pre- and post-operative WB-MRI showed decreases in all adipose tissue compartments, as well as decreased skeletal muscle and liver fat fraction ( P < 0.0001). The post-operative percentage loss of adipose tissue in subcutaneous, visceral, and intermuscular compartments (89.0%, 5.8%, 5.2%, respectively) was similar to the pre-operative percentages of corresponding adipose tissue compartments (90.5%, 5.0%, 4.5%, respectively). Of note, participants with obstructive sleep apnea had significantly higher pre-operative volume of subcutaneous and intermuscular adipose tissue than participants without obstructive sleep apnea ( P = 0.003).

CONCLUSIONS

We found, contrary to what is reported to occur in adults, that pre-operative percentage loss of adipose tissue in subcutaneous, visceral, and intermuscular compartments was similar to the post-operative percentage loss of corresponding adipose tissue compartments in adolescents 12-26 weeks after sleeve gastrectomy.

A randomized, double-blind, placebo-controlled clinical trial of 8-week intranasal oxytocin administration in adults with obesity: Rationale, study design, and methods

BACKGROUND

Obesity affects more than one-third of adults in the U.S., and effective treatment options are urgently needed. Oxytocin administration induces weight loss in animal models of obesity via effects on caloric intake, energy expenditure, and fat metabolism. We study intranasal oxytocin, an investigational drug shown to reduce caloric intake in humans, as a potential novel treatment for obesity.

METHODS

We report the rationale, design, methods, and biostatistical analysis plan of a randomized, double-blind, placebo-controlled clinical trial of intranasal oxytocin for weight loss (primary endpoint) in adults with obesity. Participants (aged 18-45 years) were randomly allocated (1:1) to oxytocin (four times daily over eight weeks) versus placebo. Randomization was stratified by biological sex and BMI (30 to <35, 35 to <40, ≥40 kg/m2). We investigate the efficacy, safety, and mechanisms of oxytocin administration in reducing body weight. Secondary endpoints include changes in resting energy expenditure, body composition, caloric intake, metabolic profile, and brain activation via functional magnetic resonance imaging in response to food images and during an impulse control task. Safety and tolerability (e.g., review of adverse events, vital signs, electrocardiogram, comprehensive metabolic panel) are assessed throughout the study and six weeks after treatment completion.

RESULTS

Sixty-one male and female participants aged 18-45 years were randomized (mean age 34 years, mean BMI 37 kg/m2). The study sample is diverse with 38% identifying as non-White and 20% Hispanic.

CONCLUSION

Investigating intranasal oxytocin's efficacy, safety, and mechanisms as an anti-obesity medication will advance the search for optimal treatment strategies for obesity and its associated severe sequelae.

The GH/IGF-1 Axis Is Associated With Intrahepatic Lipid Content and Hepatocellular Damage in Overweight/Obesity

CONTEXT

Obesity is a state of relative growth hormone (GH) deficiency, and GH has been identified as a candidate disease-modifying target in nonalcoholic fatty liver disease (NAFLD) because of its lipolytic and anti-inflammatory properties. However, the GH/IGF-1 axis has not been well characterized in NAFLD.

OBJECTIVE

We aimed to investigate serum GH and IGF-1 levels in relation to intrahepatic lipid content (IHL) and markers of hepatocellular damage and fibrosis in NAFLD.

METHODS

This cross-sectional study included 102 adults (43% women; age 19-67; BMI ≥ 25 kg/m2) without type 2 diabetes. IHL was measured by magnetic resonance spectroscopy; NAFLD was defined by ≥ 5% IHL. Peak-stimulated GH in response to GH releasing hormone and arginine was assessed as was serum IGF-1 (LC/MS).

RESULTS

There was no difference in mean age, BMI, or sex distribution in NAFLD vs controls. Mean (± SD) IHL was higher in NAFLD vs controls (21.8 ± 13.3% vs 2.9 ± 1.1%, P < 0.0001). Mean peak-stimulated GH was lower in NAFLD vs controls (9.0 ± 6.3 vs 15.4 ± 11.2 ng/mL, P = 0.003), including after controlling for age, sex, visceral adipose tissue, and fasting glucose. In a stepwise model, peak-stimulated GH predicted 14.6% of the variability in IHL (P = 0.004). Higher peak-stimulated GH was also associated with lower ALT. Higher serum IGF-1 levels were associated with lower risk of liver fibrosis by Fibrosis-4 scores.

CONCLUSION

Individuals with NAFLD have lower peak-stimulated GH levels but similar IGF-1 levels as compared to controls. Higher peak-stimulated GH levels are associated with lower IHL and less hepatocellular damage. Higher IGF-1 levels are associated with more favorable fibrosis risk scores. These data implicate GH and IGF-1 as potential disease modifiers in the development and progression of NAFLD.

A higher-protein nut-based snack product suppresses glycaemia and decreases glycaemic response to co-ingested carbohydrate in an overweight prediabetic Asian Chinese cohort: the Tū Ora postprandial RCT

Nut-based products may aid low-glycaemic dietary strategies that are important for diabetes prevention in populations at increased risk of dysglycaemia, such as Asian Chinese. This randomised cross-over trial assessed the postprandial glycaemic response (0-120 min) of a higher-protein nut-based (HP-NB) snack formulation, in bar format (1009 kJ, Nutrient Profiling Score, NPS, -2), when compared with an iso-energetic higher-carbohydrate (CHO) cereal-based bar (HC-CB, 985 kJ, NPS +3). It also assessed the ability to suppress glucose response to a typical CHO-rich food (white bread, WB), when co-ingested. Ten overweight prediabetic Chinese adults (mean, sd: age 47⋅9, 15⋅7 years; BMI 25⋅5, 1⋅6 kg/m2), with total body fat plus ectopic pancreas and liver fat quantified using dual-energy X-ray absorptiometry and magnetic resonance imaging and spectroscopy, received the five meal treatments in random order: HP-NB, HC-CB, HP-NB + WB (50 g available CHO), HC-CB + WB and WB only. Compared with HC-CB, HP-NB induced a significantly lower 30-120 min glucose response (P < 0⋅05), with an approximately 10-fold lower incremental area under the glucose curve (iAUC0-120; P < 0⋅001). HP-NB also attenuated glucose response by approximately 25 % when co-ingested with WB (P < 0⋅05). Half of the cohort had elevated pancreas and/or liver fat, with 13-21 % greater suppression of iAUC0-120 glucose in the low v. high organ fat subgroups across all five treatments. A nut-based snack product may be a healthier alternative to an energy equivalent cereal-based product with evidence of both a lower postprandial glycaemic response and modulation of CHO-induced hyperglycaemia even in high-risk, overweight, pre-diabetic adults.

Quantitative Imaging of Body Composition

Body composition refers to the amount and distribution of lean tissue, adipose tissue, and bone in the human body. Lean tissue primarily consists of skeletal muscle; adipose tissue comprises mostly abdominal visceral adipose tissue and abdominal and nonabdominal subcutaneous adipose tissue. Hepatocellular and myocellular lipids are also fat pools with important metabolic implications. Importantly, body composition reflects generalized processes such as increased adiposity in obesity and age-related loss of muscle mass known as sarcopenia.In recent years, body composition has been extensively studied quantitatively to predict overall health. Multiple imaging methods have allowed precise estimates of tissue types and provided insights showing the relationship of body composition to varied pathologic conditions. In this review article, we discuss different imaging methods used to quantify body composition and describe important anatomical locations where target tissues can be measured.

Association between muscle mass and insulin sensitivity independent of detrimental adipose depots in young adults with overweight/obesity

BACKGROUND/OBJECTIVE

Less muscle mass has been associated with greater insulin resistance, but whether the association is independent of deleterious adipose depots in young adults with overweight/obesity who are at high risk for type 2 diabetes (T2DM) but are otherwise metabolically healthy is not known. The objective of this study was to determine whether muscle mass is independently associated with insulin sensitivity (IS) in young adults with overweight/obesity.

SUBJECTS/METHODS

Cross-sectional Clinical Research Center study of 132 adults, 21-45yo, BMI ≥ 25 kg/m² and metabolically healthy without T2DM. Primary independent variable: percent ideal appendicular lean mass (ALM) calculated as measured ALM divided by predicted ALM for age, weight, and height, calculated using validated NHANES data-based equation. Primary dependent variable: IS by Matsuda index.

RESULTS

Mean age was 34.3 ± 6.8 years, and mean BMI 35.8 ± 5.8 kg/m² (mean ± SD). Individuals in the highest % ideal ALM tertile had mean IS 45% higher than the lowest tertile [6.94 ± 0.85 vs 4.80 ± 0.56 (mean ± SEM), p = 0.008] (sex interaction p = 0.003). Men in the highest % ideal ALM tertile had mean IS twice the lowest tertile (5.47 ± 0.68 vs 2.68 ± 0.34, p = 0.001), which remained significant controlling for visceral/subcutaneous and intermuscular adipose tissue, and intramyocellular and intrahepatic lipids (p = 0.03). The association was not significant in women.

CONCLUSIONS

Muscle mass is associated with IS independent of detrimental adipose depots in young men with overweight/obesity, at risk for T2DM but currently metabolically healthy. Muscle mass relative to sex, age, weight, and height-specific norms may be used to ascertain individual T2DM risk associated with low muscle mass.

Effects of Pitavastatin on Insulin Sensitivity and Liver Fat: A Randomized Clinical Trial

Context

3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) are widely prescribed. Statins may have important metabolic effects on insulin sensitivity and liver fat, but limited studies have assessed these effects by using euglycemic hyperinsulinemic clamp, stable isotopes, and 1H magnetic resonance spectroscopy (MRS) for liver fat quantification.

Objective

To study the effects of pitavastatin on hepatic fat and insulin sensitivity.

Design

Six-month, double-blind, randomized, placebo-controlled trial.

Setting

Academic clinical research center in Boston, Massachusetts.

Participants

Overweight, insulin-resistant men aged 40 to 65 years who had not received statin therapy for ≥1 year.

Interventions

Pitavastatin 4 mg or placebo daily.

Outcome

The primary endpoints were changes in insulin sensitivity measured by euglycemic hyperinsulinemic clamp and liver fat measured by 1H MRS.

Results

Pitavastatin showed no effect on endogenous glucose production (ΔRa glucose 0.07 ± 0.07 vs 0.04 ± 0.07 mg/kg/min, pitavastatin vs placebo, P = 0.76) or insulin-stimulated glucose uptake during "low dose" (ΔM 0.1 ± 0.1 vs -0.3 ± 0.2 mg/kg/min, P = 0.11) and "high dose" (ΔM -0.5 ± 0.3 vs -0.7 ± 0.4 mg/kg/min, P = 0.70) euglycemic hyperinsulinemic clamps. There was also no effect of pitavastatin on fasting glucose, HbA1c, and 2-hour glucose after 75-g glucose challenge. There was also no change in liver fat fraction (-1 ± 1 vs -0 ± 1%, P = 0.56).

Conclusion

Compared with placebo, pitavastatin did not affect hepatic or whole-body insulin sensitivity, and it did not reduce liver fat.

Significant Association of Aldosterone and Liver Fat Among HIV-Infected Individuals With Metabolic Dysregulation

Objective

Fatty liver disease is increased among individuals with HIV. We sought to explore how aldosterone, a key hormone linked to insulin resistance and inflammation, relates to liver fat in the large population of individuals with HIV and metabolic abnormalities.

Methods

Forty-six individuals with HIV and increased waist circumference and dysglycemia were assessed for liver fat using proton magnetic resonance spectroscopy. Serum aldosterone level was obtained following strictly controlled posture conditions and a standardized sodium diet and was related to liver fat.

Results

Among the entire group [median (interquartile range) liver fat: 5% (3%, 12%) and homeostatic model assessment of insulin resistance: 1.74 (1.21, 2.83)], serum aldosterone significantly correlated with liver fat (r = 0.31; P = 0.049). Liver fat level was significantly higher in those with aldosterone above vs below the median [8% (3%, 20%) vs 4% (2%, 10%); P = 0.02]. In the presence of metabolic syndrome, individuals with aldosterone levels above vs below the median had markedly elevated liver fat values [14% (9%, 23%) vs 5% (3%, 12%); P = 0.005] and increased presence of fatty liver disease (FLD; 92% vs 50%; P = 0.02). Controlling for metabolic syndrome, hepatitis C virus, and alcohol use, aldosterone was a significant and independent predictor of liver fat (β estimate: 0.6038, P = 0.01; overall model r² = 0.41, P = 0.0005) and FLD (OR: 1.38, P = 0.02; overall model r² = 0.28, P = 0.002).

Conclusion

These data highlight a robust association between aldosterone and liver fat among individuals with HIV and metabolic dysregulation. Increased aldosterone may be a risk factor for liver fat accumulation among the population with HIV.

Sex differences in body composition and association with cardiometabolic risk

Background

Body composition differs between men and women, with women having proportionally more fat mass and men more muscle mass. Although men and women are both susceptible to obesity, health consequences differ between the sexes. The purpose of our study was to assess sex differences in body composition using anatomic and functional imaging techniques, and its relationship to cardiometabolic risk markers in subjects with overweight/obesity.

Methods

After written informed consent, we prospectively recruited 208 subjects with overweight/obesity who were otherwise healthy (94 men, 114 women, age 37 ± 10 years, BMI 35 ± 6 kg/m²). Subjects underwent dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) for fat and muscle mass, proton MR spectroscopy (1H-MRS) for intrahepatic (IHL) and intramyocellular lipids (IMCL), an oral glucose tolerance test, serum insulin, lipids, and inflammatory markers. Men and women were compared by Wilcoxon signed rank test. Linear correlation and multivariate analyses between body composition and cardiometabolic risk markers were performed.

Results

Women and men were of similar mean age and BMI (p ≥ 0.2). Women had higher %fat mass, extremity fat, and lower lean mass compared to men (p ≤ 0.0005). However, men had higher visceral adipose tissue (VAT) and IMCL and higher age-and BMI-adjusted IHL (p < 0.05). At similar age and BMI, men had a more detrimental cardiometabolic risk profile compared to women (p < 0.01). However, VAT in women, and IMCL in men, were more strongly associated with cardiometabolic risk markers, while more lower extremity fat was associated with a more favorable cardiometabolic profile in women compared to men (p ≤ 0.03).

Conclusions

Although the male pattern of fat distribution is associated with a more detrimental cardiometabolic risk profile compared to women of similar age and BMI, VAT is more strongly associated with cardiometabolic risk markers in women, while IMCL are more detrimental in men. Lower extremity fat is relatively protective, in women more than in men. This suggests that detailed anatomic and functional imaging, rather than BMI, provides a more complete understanding of metabolic risk associated with sex differences in fat distribution.

Sex Differences in Body Composition

Body composition differs between men and women. Men have more lean mass, and women have more fat mass than men. Men are more likely to accumulate adipose tissue around the trunk and abdomen, whereas women usually accumulate adipose tissue around the hips and thighs. Less is known about sex differences in ectopic fat depots. Advances in imaging allow the noninvasive assessment of abdominal and femorogluteal fat compartments, intramyocellular lipids, intrahepatic lipids, pericardial adipose tissue, and neck adipose tissue including brown adipose tissue and tongue adipose tissue. In this review, sex differences of regional adipose tissue, muscle mass, ectopic lipids, and brown adipose tissue and their effects on cardiometabolic risk will be discussed. In addition, novel imaging techniques to quantify these body composition compartments noninvasively will be described.

Fibroblast growth factor 21 decreases after liver fat reduction via growth hormone augmentation

OBJECTIVE

Fibroblast growth factor 21 (FGF21) ameliorates steatohepatitis but is increased in humans with fatty liver, potentially due to compensatory mechanisms and/or FGF21 resistance. Further, animal models suggest that GH increases serum FGF21. Tesamorelin, a growth hormone releasing hormone agonist, reduces liver fat in HIV-infected individuals. The objectives of this study were to investigate changes in FGF21 during tesamorelin treatment, to elucide the interplay between FGF21, GH augmentation, and liver fat reduction in humans.

METHODS

50 HIV-infected men and women with increased abdominal adiposity participated in this randomized, placebo-controlled trial of tesamorelin, 2mg vs. identical placebo daily for six months. Fasting laboratory measures, liver fat by 1H-magnetic resonance spectroscopy, and visceral adipose tissue (VAT) by computed tomography were obtained. Euglycemic hyperinsulinemic clamp was performed in a randomly selected subset.

RESULTS

At baseline, serum log10 FGF21 was significantly associated with log10 liver fat (r=0.32, p=0.03). Log10 FGF21 tended to decrease in the tesamorelin group compared to placebo (p=0.06). Among the entire cohort, reductions in FGF21 were significantly associated with reductions in liver fat (ρ=0.41, p=0.01), log10 gamma glutamyl tran speptidase (GGT, r=0.40, p=0.009), and FIB4 index (r=0.37, p=0.02).

CONCLUSIONS

In HIV-infected individuals, FGF21 is significantly positively associated with liver fat. FGF21 decreases in association with reductions in liver fat, GGT, and FIB4, suggesting that FGF21 is upregulated in the context of steatosis and steatohepatitis and is reduced when these conditions improve. Moreover, these data suggest that tesamorelin improves liver fat via pathways other than increasing serum FGF21.

TRIAL REGISTRATION

clinicaltrials.govNCT01263717.

Body Composition and Ectopic Lipid Changes With Biochemical Control of Acromegaly

CONTEXT

Acromegaly is characterized by growth hormone (GH) and insulinlike growth factor-1 (IGF-1) hypersecretion, and GH and IGF-1 play important roles in regulating body composition and glucose homeostasis.

OBJECTIVE

The purpose of our study was to investigate body composition including ectopic lipids, measures of glucose homeostasis, and gonadal steroids in patients with active acromegaly compared with age-, body mass index (BMI)-, and sex-matched controls and to determine changes in these parameters after biochemical control of acromegaly.

DESIGN

Cross-sectional study of 20 patients with active acromegaly and 20 healthy matched controls. Prospective study of 16 patients before and after biochemical control of acromegaly.

MAIN OUTCOME MEASURES

Body composition including ectopic lipids by magnetic resonance imaging/proton magnetic resonance spectroscopy; measures of glucose homeostasis by an oral glucose tolerance test; gonadal steroids.

RESULTS

Patients with active acromegaly had lower mean intrahepatic lipid (IHL) and higher mean fasting insulin and insulin area under the curve (AUC) values than controls. Men with acromegaly had lower mean total testosterone, sex hormone-binding globulin, and estradiol values than male controls. After therapy, homeostasis model assessment of insulin resistance, fasting insulin level, and insulin AUC decreased despite an increase in IHL and abdominal and thigh adipose tissues and a decrease in muscle mass.

CONCLUSIONS

Patients with acromegaly were characterized by insulin resistance and hyperinsulinemia but lower IHL compared with age-, BMI-, and sex-matched healthy controls. Biochemical control of acromegaly improved insulin resistance but led to a less favorable anthropometric phenotype with increased IHL and abdominal adiposity and decreased muscle mass.

Multiple breath-hold proton spectroscopy of human liver at 3T: Relaxation times and concentrations of glycogen, choline, and lipids

PURPOSE

To evaluate the feasibility of an expiration multiple breath-hold ¹ H-MRS technique to measure glycogen (Glycg), choline-containing compounds (CCC), and lipid relaxation times T₁ , T₂ , and their concentrations in normal human liver.

MATERIALS AND METHODS

Thirty healthy volunteers were recruited. Experiments were performed at 3T. Multiple expiration breath-hold single-voxel point-resolved spectroscopy (PRESS) technique was used for localization. Water-suppressed spectra were used for the estimation of Glycg, CCC, lipid methylene (CH₂ )_n relaxation times and concentrations. Residual water lines were removed by the Hankel Lanczos singular value decomposition filter. After phase correction and frequency alignment, spectra were averaged and processed by LCModel. Summed signals of Glycg resonances H2H4', H3, and H5 between 3.6 and 4 ppm were used to estimate their apparent relaxation times and concentration. Glycg, CCC, and lipid content were estimated from relaxation corrected spectral intensity ratios to unsuppressed water line.

RESULTS

Relaxation times were measured for liver Glycg (T₁ , 892 ± 126 msec; T₂ , 13 ± 4 msec), CCC (T₁ , 842 ± 75 msec; T₂ , 50 ± 5 msec), lipid (CH₂ )_n (T₁ , 402 ± 19 msec; T₂ , 52 ± 3 msec), and water (T₁ , 990 ± 89 msec; T₂ , 30 ± 2 msec). Mean CCC and lipid concentrations of healthy liver were 7.8 ± 1.3 mM and 15.8 ± 23.6 mM, respectively. Glycg content was found lower in the morning (48 ± 21 mM) compared to the afternoon (145 ± 50 mM).

CONCLUSION

Multiple breath-hold ¹ H-MRS together with dedicated postprocessing is a feasible technique for the quantification of liver Glycg, CCC, and lipid relaxation times and concentrations.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:410-417.

Short- and Long-Term Reproducibility of Intrahepatic Lipid Quantification by 1H-MR Spectroscopy and CT in Obesity

OBJECTIVE

This study aimed to assess short- and long-term reproducibility of intrahepatic lipid (IHL) quantification by proton magnetic resonance spectroscopy (H-MRS) and computed tomography (CT).

METHODS

Sixteen obese subjects underwent H-MRS using a single-voxel point-resolved single-voxel spectroscopy sequence at 3 T and noncontrast single-slice CT of the liver. Measurements were repeated after 6 weeks and 6 months. Clinical parameters (weight, activity, serum lipids) were collected. Short-term (baseline to 6 weeks) and long-term (baseline to 6 months) reproducibility of IHL was assessed by coefficient of variance (CV), SD, and intraclass correlation coefficient (ICC).

RESULTS

Short-term reproducibility and long-term reproducibility of H-MRS were as follows: CV, 5.9% to 18.8%; SD, 0.7 to 1.9; and ICC, 0.998 to 0.995 (95% confidence interval, 0.942-0.999). Short-term reproducibility and long-term reproducibility of CT were as follows: CV, 4.4% to 14.2%; SD, 2.4 to 8.7; and ICC, 0.766 to 0.982 (95% confidence interval, 0.271-0.994). There was no significant change in clinical parameters (P > 0.3).

CONCLUSIONS

Proton magnetic resonance spectroscopy and CT are reproducible methods for short- and long-term quantification of IHL content. Our results can guide sample size calculations for interventional and longitudinal studies.

Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients with abdominal fat accumulation: a randomized clinical trial

IMPORTANCE

Among patients infected with human immunodeficiency virus (HIV), visceral adiposity is associated with metabolic dysregulation and ectopic fat accumulation. Tesamorelin, a growth hormone-releasing hormone analog, specifically targets visceral fat reduction but its effects on liver fat are unknown.

OBJECTIVE

To investigate the effect of tesamorelin on visceral and liver fat.

DESIGN, SETTING, AND PATIENTS

Double-blind, randomized, placebo-controlled trial conducted among 50 antiretroviral-treated HIV-infected men and women with abdominal fat accumulation at Massachusetts General Hospital in Boston. The first patient was enrolled on January 10, 2011; for the final patient, the 6-month study visit was completed on September 6, 2013.

INTERVENTIONS

Participants were randomized to receive tesamorelin, 2 mg (n=28), or placebo (n=22), subcutaneously daily for 6 months.

MAIN OUTCOMES AND MEASURES

Primary end points were changes in visceral adipose tissue and liver fat. Secondary end points included glucose levels and other metabolic end points.

RESULTS

Forty-eight patients received treatment with study drug. Tesamorelin significantly reduced visceral adipose tissue (mean change, -34 cm2 [95% CI, -53 to -15 cm2] with tesamorelin vs 8 cm2 [95% CI, -14 to 30 cm2] with placebo; treatment effect, -42 cm2 [95% CI, -71 to -14 cm2]; P = .005) and liver fat (median change in lipid to water percentage, -2.0% [interquartile range {IQR}, -6.4% to 0.1%] with tesamorelin vs 0.9% [IQR, -0.6% to 3.7%] with placebo; P = .003) over 6 months, for a net treatment effect of -2.9% in lipid to water percentage. Fasting glucose increased in the tesamorelin group at 2 weeks (mean change, 9 mg/dL [95% CI, 5-13 mg/dL] vs 2 mg/dL [95% CI, -3 to 8 mg/dL] in the placebo group; treatment effect, 7 mg/dL [95% CI, 1-14 mg/dL]; P = .03), but changes at 6 months in fasting glucose (mean change, 4 mg/dL [95% CI, -2 to 10 mg/dL] with tesamorelin vs 2 mg/dL [95% CI, -4 to 7 mg/dL] with placebo; treatment effect, 2 mg/dL [95% CI, -6 to 10 mg/dL]; P = .72 overall across time points) and 2-hour glucose (mean change, -1 mg/dL [95% CI, -18 to 15 mg/dL] vs -8 mg/dL [95% CI, -24 to 8 mg/dL], respectively; treatment effect, 7 mg/dL [95% CI, -16 to 29 mg/dL]; P = .53 overall across time points) were not significant.

CONCLUSIONS AND RELEVANCE

In this preliminary study of HIV-infected patients with abdominal fat accumulation, tesamorelin administered for 6 months was associated with reductions in visceral fat and additionally with modest reductions in liver fat. Further studies are needed to determine the clinical importance and long-term consequences of these findings.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01263717.

Effects of growth hormone administration for 6 months on bone turnover and bone marrow fat in obese premenopausal women

PURPOSE

Abdominal adiposity is associated with low BMD and decreased growth hormone (GH) secretion, an important regulator of bone homeostasis. The purpose of our study was to determine the effects of a short course of GH on markers of bone turnover and bone marrow fat in premenopausal women with abdominal adiposity.

MATERIALS AND METHODS

In a 6-month, randomized, double-blind, placebo-controlled trial we studied 79 abdominally obese premenopausal women (21-45 y) who underwent daily sc injections of GH vs. placebo. Main outcome measures were body composition by DXA and CT, bone marrow fat by proton MR spectroscopy, P1NP, CTX, 25(OH)D, hsCRP, undercarboxylated osteocalcin (ucOC), preadipocyte factor 1 (Pref 1), apolipoprotein B (ApoB), and IGF-1.

RESULTS

GH increased IGF-1, P1NP, 25(OH)D, ucOC, bone marrow fat and lean mass, and decreased abdominal fat, hsCRP, and ApoB compared with placebo (p<0.05). There was a trend toward an increase in CTX and Pref-1. Among all participants, a 6-month increase in IGF-1 correlated with 6-month increase in P1NP (p=0.0005), suggesting that subjects with the greatest increases in IGF-1 experienced the greatest increases in bone formation. A six-month decrease in abdominal fat, hsCRP, and ApoB inversely predicted 6-month change in P1NP, and 6-month increase in lean mass and 25(OH)D positively predicted 6-month change in P1NP (p≤0.05), suggesting that subjects with greatest decreases in abdominal fat, inflammation and ApoB, and the greatest increases in lean mass and 25(OH)D experienced the greatest increases in bone formation. A six-month increase in bone marrow fat correlated with 6-month increase in P1NP (trend), suggesting that subjects with the greatest increases in bone formation experienced the greatest increases in bone marrow fat. Forward stepwise regression analysis indicated that increase in lean mass and decrease in abdominal fat were positive predictors of P1NP. When IGF-1 was added to the model, it became the only predictor of P1NP.

CONCLUSION

GH replacement in abdominally obese premenopausal women for 6 months increased bone turnover and bone marrow fat. Reductions in abdominal fat, and inflammation, and increases in IGF-1, lean mass and vitamin D were associated with increased bone formation. The increase in bone marrow fat may reflect changes in energy demand from increased bone turnover.

Navigator based respiratory gating during acquisition and preparation phases for proton liver spectroscopy at 3 T

Proton magnetic resonance spectroscopy ((1)H MRS) enables the non-invasive investigation of the human liver; however, because of technical difficulties it is not regularly used for diagnosis of liver diseases in clinical routine. Breathing motion is one of the major challenges, as it decreases spectral quality and leads to misplacement of the spectroscopic voxel. To overcome this problem, real-time navigator gating for spectral acquisition and preparation steps (B0 shimming, water frequency determination, receiver gain optimization, and water suppression) combined with short TE , optimized first order projection based B0 shimming, water suppression, and inner-volume saturated point resolved spectroscopy (PRESS) at 3 T is suggested. Simultaneous lipid and trimethylamine quantification is demonstrated by means of phantom, volunteer, and representative patient measurements. Precise localization of the voxel despite respiratory motion, increased spectral quality (higher signal-to-noise ratio and reduced linewidth) compared with measurements without respiratory gating, and the possibility of acquiring data without additional subject instructions regarding breathing enable robust and accurate liver (1)H MRS measurements with this novel acquisition protocol.

Assessment of abdominal fat compartments using DXA in premenopausal women from anorexia nervosa to morbid obesity

OBJECTIVE

To test a newly developed dual energy X-ray absorptiometry (DXA) method for abdominal fat depot quantification in subjects with anorexia nervosa (AN), normal weight, and obesity using CT as a gold standard.

DESIGN AND METHODS

135 premenopausal women (overweight/obese: n = 89, normal-weight: n = 27, AN: n = 19); abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and total adipose tissue (TAT) areas determined on CT and DXA.

RESULTS

There were strong correlations between DXA and CT measurements of abdominal fat compartments in all groups with the strongest correlation coefficients in the normal-weight and overweight/obese groups. Correlations of DXA and CT VAT measurements were strongest in the obese group and weakest in the AN group. DXA abdominal fat depots were higher in all groups compared to CT, with the largest % mean difference in the AN group and smallest in the obese group.

CONCLUSION

A new DXA technique is able to assess abdominal fat compartments including VAT in premenopausal women across a large weight spectrum. However, DXA measurements of abdominal fat were higher than CT, and this percent bias was most pronounced in the AN subjects and decreased with increasing weight, suggesting that this technique may be more useful in obese individuals.

Ectopic and serum lipid levels are positively associated with bone marrow fat in obesity

PURPOSE

To investigate the associations between ectopic and serum lipid levels and bone marrow fat, as a marker of stem cell differentiation, in young obese men and women, with the hypothesis that ectopic and serum lipid levels would be positively associated with bone marrow fat.

MATERIALS AND METHODS

The study was institutional review board approved and complied with HIPAA guidelines. Written informed consent was obtained. The study group comprised 106 healthy young men and women (mean age, 33.7 years ± 6.8 [standard deviation]; range, 19-45 years; mean body mass index (BMI), 33.1 kg/m(2) ± 7.1; range, 18.1-48.8 kg/m(2)) who underwent hydrogen 1((1)H) magnetic resonance (MR) spectroscopy by using a point-resolved spatially localized spectroscopy sequence at 3.0 T of L4 for bone marrow fat content, of soleus muscle for intramyocellular lipids (IMCL), and liver for intrahepatic lipids (IHL), serum cholesterol level, serum triglyceride level, and measures of insulin resistance (IR). Exercise status was assessed with the Paffenbarger activity questionnaire.

RESULTS

There was a positive correlation between bone marrow fat and IHL (r = 0.21, P = .048), IMCL (r = 0.27, P = .02), and serum triglyceride level (r = 0.33, P = .001), independent of BMI, age, IR, and exercise status (P < .05). High-density lipoprotein cholesterol levels were inversely associated with bone marrow fat content, independent of BMI, age, IR, and exercise status (r = -0.21, P = .019).

CONCLUSION

Results of this study suggest that ectopic and serum lipid levels are positively associated with bone marrow fat in obese men and women.

Ectopic and serum lipid levels are positively associated with bone marrow fat in obesity

PURPOSE

To investigate the associations between ectopic and serum lipid levels and bone marrow fat, as a marker of stem cell differentiation, in young obese men and women, with the hypothesis that ectopic and serum lipid levels would be positively associated with bone marrow fat.

MATERIALS AND METHODS

The study was institutional review board approved and complied with HIPAA guidelines. Written informed consent was obtained. The study group comprised 106 healthy young men and women (mean age, 33.7 years ± 6.8 [standard deviation]; range, 19-45 years; mean body mass index (BMI), 33.1 kg/m(2) ± 7.1; range, 18.1-48.8 kg/m(2)) who underwent hydrogen 1((1)H) magnetic resonance (MR) spectroscopy by using a point-resolved spatially localized spectroscopy sequence at 3.0 T of L4 for bone marrow fat content, of soleus muscle for intramyocellular lipids (IMCL), and liver for intrahepatic lipids (IHL), serum cholesterol level, serum triglyceride level, and measures of insulin resistance (IR). Exercise status was assessed with the Paffenbarger activity questionnaire.

RESULTS

There was a positive correlation between bone marrow fat and IHL (r = 0.21, P = .048), IMCL (r = 0.27, P = .02), and serum triglyceride level (r = 0.33, P = .001), independent of BMI, age, IR, and exercise status (P < .05). High-density lipoprotein cholesterol levels were inversely associated with bone marrow fat content, independent of BMI, age, IR, and exercise status (r = -0.21, P = .019).

CONCLUSION

Results of this study suggest that ectopic and serum lipid levels are positively associated with bone marrow fat in obese men and women.

Effects of growth hormone withdrawal in obese premenopausal women

OBJECTIVE

We previously reported improved body composition and cardiovascular risk markers plus a small decrease in glucose tolerance with GH administration vs placebo for 6 months to abdominally obese premenopausal women. The objective of this study was to determine whether the effects of GH treatment on cardiovascular risk markers, body composition and glucose tolerance in obese women persist 6 months after GH withdrawal.

DESIGN AND PATIENTS

Fifty abdominally obese premenopausal women completed a trial of rhGH vs placebo for 6 months; thirty-nine women completed a subsequent 6-month withdrawal observation period.

MEASUREMENTS

IGF-I, body composition by CT, (1) H-MRS and DXA, serum cardiovascular risk markers, oral glucose tolerance test (OGTT).

RESULTS

IGF-I standard deviation scores (SDS) within the GH group were -1.7 ± 0.1 (pretreatment),-0.1 ± 0.3 (after 6 months of GH) and -1.7 ± 0.1 (6 months post-GH withdrawal). Six months after GH withdrawal, total abdominal and subcutaneous adipose tissue, total fat, trunk fat, trunk/extremity fat, hsCRP, apoB, LDL, and tPA were higher than at the 6-month (GH discontinuation) timepoint (P ≤ 0.05). All body composition and cardiovascular risk markers that had improved with GH returned to baseline levels by 6 months after GH discontinuation, as did fasting and 2-h OGTT glucose levels.

CONCLUSION

The effects of GH administration to abdominally obese premenopausal women have a short time-course. The beneficial effects on body composition and cardiovascular risk markers, and the side effect of altered glucose tolerance returned to pretreatment levels after GH withdrawal. There was no suppression of endogenous IGF-I levels, which returned to baseline after GH withdrawal.

Quantitative analysis of hepatic fat fraction by single-breath-holding MR spectroscopy with T₂ correction: phantom and clinical study with histologic assessment

The focus of this study was on the investigation of the accuracy of the fat fraction of the liver by use of single-breath-holding magnetic resonance spectroscopy (MRS) with T (2) correction. Single-voxel proton MRS was performed with several TE values, and the fat fraction was determined with and without T (2) correction. MRS was also performed with use of the point-resolved spectroscopy sequence in single breath holding. The T (2) values of both water and fat were determined separately at the same time, and the effect of T (2) on the fat fraction was corrected. In addition, MRS-based fat fractions were compared with the degree of hepatic steatosis (HS) by liver biopsy in human subjects. With T (2) correction, the MRI-derived fat fractions were in good agreement with the fat fractions in all phantoms, but the fat fractions were overestimated without T (2) correction. R (2) values were in good agreement with the preset iron concentrations in the phantoms. The MRI-derived fat fraction was well correlated with the degree of HS. Iron deposited in the liver affects the signal strength when proton MRS is used for detection of the fat signal in the liver. However, the fat signal can be evaluated more accurately when the T (2) correction is applied. Breath-holding MRS minimizes the respiratory motion, and it can be more accurate in the quantification of the hepatic fat fraction.

Liver metabolite concentrations measured with 1H MR spectroscopy

PURPOSE

To determine the feasibility of measuring choline and glycogen concentrations in normal human liver in vivo with proton (hydrogen 1 [1H]) magnetic resonance (MR) spectroscopy.

MATERIALS AND METHODS

Signed consent to participate in an institutional review board-approved and HIPAA-compliant study was obtained from 46 subjects (mean age, 46 years±17 [standard deviation]; 24 women) consecutively recruited during 285 days. Navigator-gated MR images were used to select 8-mL volumes for point-resolved spectroscopy (PRESS) with a 35-msec echo time. Line widths were minimized with fast breath-hold B0 field mapping and further manual shimming. Navigator-gated spectra were recorded with and without water suppression to determine metabolite concentrations with water signals as an internal reference. In three subjects, echo time was varied to determine the glycogen and choline T2. Linear regression analysis was used to examine relations between choline, hepatic lipid content, body mass index, glycogen content, and age.

RESULTS

Choline concentrations could be determined in 46 of 48 studies and was found to be 8.6 mmol per kilogram of wet weight±3.1 (range, 3.8-17.6; n=44). Twenty-seven spectra in 25 individuals with narrow line widths and low lipid content were adequate for quantitation of glycogen. The glycogen (glucosyl unit) concentration was 38.1 mmol/kg wet weight±14.4. The T2 of combined glycogen peaks in the liver of three subjects was 36 msec±8. Choline levels showed a weak but significant correlation with glycogen (r2=0.15; P<.05) but not with lipid content.

CONCLUSION

Navigator-gated and gradient-echo shimmed PRESS 1H MR spectroscopy may allow quantification of liver metabolites that are important for understanding and identifying disorders of glucose and lipid metabolism.

Effects of GH in women with abdominal adiposity: a 6-month randomized, double-blind, placebo-controlled trial

OBJECTIVE

Abdominal adiposity is associated with increased cardiovascular risk and decreased GH secretion. The objective of our study was to determine the effects of GH on body composition and cardiovascular risk markers in abdominally obese women.

MATERIALS AND METHODS

In this randomized, double-blind, placebo-controlled study, 79 obese premenopausal women received GH vs placebo for 6 months. Primary endpoints were i) total abdominal (total abdominal adipose tissue, TAT) fat by computed tomography (CT) (body composition) and ii) high-sensitivity C-reactive protein (hsCRP) (cardiovascular risk marker). Body composition was assessed by CT, dual-energy X-ray absorptiometry, and proton MR spectroscopy. Serum cardiovascular risk markers, carotid intima-media thickness, and endothelial function were measured.

RESULTS

Mean 6-month GH dose was 1.7±0.1 mg/day, resulting in a mean IGF1 SDS increase from -1.7±0.08 to -0.1±0.3 in the GH group. GH administration decreased TAT and hsCRP compared with placebo. In addition, it increased thigh muscle mass and lean body mass and decreased subcutaneous abdominal and trunk fat, tissue plasminogen activator, apoB, and apoB/low-density lipoprotein compared with placebo. Visceral adipose tissue (VAT) decreased and intramyocellular lipid increased within the GH group. Six-month change in IGF1 levels was negatively associated with 6-month decrease in TAT and VAT. One subject had a 2 h glucose >200 mg/ml at 3 months; four subjects, three of whom were randomized to GH, had 2 h glucose levels >200 mg/ml at the end of the study.

CONCLUSION

GH administration in abdominally obese premenopausal women exerts beneficial effects on body composition and cardiovascular risk markers but is associated with a decrease in glucose tolerance in a minority of women.

The metabolic features of normal pancreas and pancreatic adenocarcinoma: preliminary result of in vivo proton magnetic resonance spectroscopy at 3.0 T

OBJECTIVE

The objective of the study was to analyze the metabolic features and distribution of normal pancreas and pancreatic adenocarcinoma while determining the biomarker of pancreatic cancerous process.

METHODS

Twenty-seven control and 29 pancreatic adenocarcinoma patients underwent breath-hold 3-T proton magnetic resonance spectroscopy. The ratios of lipid (lipid/InW), choline-containing compounds (CCCs/InW), and fatty acids (FAs/InW) to nonsaturated internal water (InW) of the normal pancreas head and body-tail region, with cancerous and noncancerous regions in pancreatic adenocarcinoma, were calculated.

RESULTS

In normal pancreas, there were no statistical difference in the ratios of FAs to InW and lipid to InW of different regions, but CCCs/InW of body-tail area was greater than that of head (7.28 × 10⁻⁴ vs 3.23 × 10⁻⁴). In pancreatic cancer, FAs/InW and lipid/InW between cancerous and noncancerous region were different (3.44 × 10⁻⁴ vs 16.3 × 10⁻⁴ and 7.78 × 10⁻⁴ vs 36.3 × 10⁻⁴, respectively). Choline-containing compounds/InW in cancerous region was smaller than that in noncancerous region of pancreatic head cancer (1.62 × 10⁻⁴ vs 5.69 × 10⁻⁴) but similar to such region in body-tail cancer. Lipid/InW dropped in noncancerous regions (from 0.67 to 0.36), whereas there were no differences in FAs/InW and CCCs/InW between normal pancreas regions and noncancerous regions in pancreatic cancer.

CONCLUSIONS

In normal pancreas, CCCs of body-tail region was greater than that of head. Whereas in pancreatic adenocarcinoma, CCCs, FAs, and lipid were all decreased in cancerous region, lipid in the noncancerous region was also decreased compared with normal pancreas. Lipid may be the potential sensitive biomarker for pancreatic cancer.

Adiponectin is inversely associated with intramyocellular and intrahepatic lipids in obese premenopausal women

Adiponectin, an adipokine secreted by adipocytes, exerts beneficial effects on glucose and lipid metabolism and has been found to improve insulin resistance by decreasing triglyceride content in muscle and liver in obese mice. Adiponectin is found in several isoforms and the high-molecular weight (HMW) form has been linked most strongly to the insulin-sensitizing effects. Fat content in skeletal muscle (intramyocellular lipids, IMCL) and liver (intrahepatic lipids, IHL) can be quantified noninvasively using proton magnetic resonance spectroscopy ((1)H-MRS). The purpose of our study was to assess the relationship between HMW adiponectin and measures of glucose homeostasis, IMCL and IHL, and to determine predictors of adiponectin levels. We studied 66 premenopausal women (mean BMI 31.0 ± 6.6 kg/m(2)) who underwent (1)H-MRS of calf muscles and liver for IMCL and IHL, computed tomography (CT) of the abdomen for abdominal fat depots, dual-energy X-ray absorptiometry (DXA) for fat and lean mass assessments, HMW and total adiponectin, fasting lipid profile and an oral glucose tolerance test (homeostasis model assessment of insulin resistance (HOMA(IR)), glucose and insulin area under the curve). There were strong inverse associations between HMW adiponectin and measures of insulin resistance, IMCL and IHL, independent of visceral adipose tissue (VAT) and total body fat. IHL was the strongest predictor of adiponectin and adiponectin was a predictor of HOMA(IR). Our study showed that in premenopausal obese women HMW adiponectin is inversely associated with IMCL and IHL content. This suggests that adiponectin exerts positive effects on insulin sensitivity in obesity by decreasing intracellular triglyceride content in skeletal muscle and liver; it is also possible that our results reflect effects of insulin on adiponectin.