Hepatic steatosis in overweight/obese females: New screening method for those at risk

AIM: To identify which parameters could help to distinguish the “metabolically benign obesity”, which is not accompanied by insulin resistance (IR) and early atherosclerosis.

METHODS: Eighty two of 124 overweight/obese females formed the study population, which was divided into two groups (52 and 30 subjects, respectively) with and without IR according to a HO meostatic Metabolic Assessment (HOMA) cut-off of 2, and were studied in a cross-sectional manner. The main outcome measures were waist circumference, serum uric acid, high-density lipoprotein-cholesterol and triglycerides, alanine aminotransferase, blood pressure and the two imaging parameters, hepatic steatosis and longitudinal diameter of the spleen, which were measured in relation to the presence/absence of IR.

RESULTS: A variable grade of visceral obesity was observed in all subjects with the exception of three. Obesity of a severe grade was represented more in the group of IR individuals (P = 0.01). Hepatic steatosis, revealed at ultrasound, was more pronounced in IR than in non-IR subjects (P = 0.005). The two groups also demonstrated a clear difference in longitudinal spleen diameter and blood pressure, with raised and significant values in the IR group. Metabolic syndrome was frequent in the IR group, and was not modified when adjusted for menopause (P = 0.001). At linear regression, the β values of waist circumference and body mass index predicting HOMA were 0.295, P = 0.007 and 0.41, P = 0.0001, respectively. Measures of spleen longitudinal diameter were well predicted by body mass index (BMI) values, β = 0.35, P = 0.01, and by HOMA, β = 0.41, P = 0.0001. Blood pressure was predicted by HOMA values, β = 0.39, P = 0.0001). HOMA and hepatic steatosis were highly associated (rho = 0.34, P = 0.002). Interestingly, IR patients were almost twice as likely to have hepatic steatosis as non-IR patients. Among the MS criteria, blood pressure was very accurate in identifying the presence of IR (AUROC for systolic blood pressure 0.66, cut-off 125 mm of Hg, sensibility 64%, specificity 75%; AUROC for diastolic blood pressure 0.70, cut-off 85 mm of Hg, sensibility 54.5%, specificity 75%).

CONCLUSION: As health care costs are skyrocketing, reliable and mainly inexpensive tools are advisable to better define subjects who really need to lose weight.

Young adult obese subjects with and without insulin resistance: what is the role of chronic inflammation and how to weigh it non-invasively?

BACKGROUND

Obesity is a leading risk factor for metabolic syndrome whose further expression is non-alcoholic fatty liver disease. Metabolic syndrome is associated with a proinflammatory state that contributes to insulin resistance. Finally, a "metabolically benign obesity" that is not accompanied by insulin resistance has recently been postulated to exist.

AIM

To find whether any inflammation markers were independently associated with the presence of insulin resistance, evaluating specific anthropometric, ultrasonographic and laboratory parameters in a population of young adult obese subjects.

METHODS

Of forty two young individuals, divided into two groups (with or without insulin resistance), were studied serum C-reactive protein and fibrinogen as indexes of chronic pro-inflammatory status. Body mass index, waist circumference and metabolic syndrome presence were assessed as part of the metabolic evaluation. Ultrasonography weighted visceral and subcutaneous abdominal fat thickness, spleen size as longitudinal diameter and liver hyperechogenicity.

RESULTS AND DISCUSSION

Serum C-reactive protein and fibrinogen as well as spleen longitudinal diameter were significantly increased in the obese young with insulin resistance compared to non-insulin resistance group. Insulin resistance was significantly associated with hepatic steatosis score at sonography (r = 0.33, P = 0.03), spleen longitudinal diameter (r = 0.35, P = 0.02) and C-reactive protein (r = 0.38, P = 0.01), but not with body mass index, visceral or subcutaneous abdominal adipose tissue, waist circumference and fibrinogen (P = 0.18, 0.46, 0.33, 0.37 and 0.4, respectively). Steatosis score at sonography was well associated with spleen volume (rho = 0.40, P = 0.01) and C-reactive protein levels (rho = 0.49, P = 0.002). Metabolic syndrome was much more frequent in obese patients with insulin resistance. These findings show that in young adults the only abdominal adiposity without insulin resistance, plays a scarce role in determining hepatic steatosis as well as metabolic syndrome.

CONCLUSION

Increases in spleen size and CRP levels represent a reliable tool in diagnosing insulin resistance.

Non-alcoholic fatty liver disease in young adult severely obese non-diabetic patients in South Italy

BACKGROUND/AIMS

In the absence of other causes, obesity increases the risk of liver disease. We evaluated the prevalence and degree of metabolic and hepatic abnormalities associated with non-alcoholic fatty liver disease (NAFLD) in type II-III obesity in a metropolitan area of South Italy.

METHODS

187 (81 M, 106 F) young adult non-diabetic obese patients, age range 18-50 years (mean 31.9 +/- 8.8), body mass index (BMI) > or =30 (mean 47.5 +/- 9.6), consecutively admitted from January 2000 to April 2003 to the Obesity Outpatients Clinic entered into the study. Patients were divided into two groups: (1) BMI 30.0-39.9, and (2) BMI> or =40. Ultrasound detected liver steatosis was classified as: (I) mild; (II) moderate, and (III) severe.

RESULTS

All patients, except 4, showed a variable degree of steatosis: mild was more frequent among females, severe steatosis present only in grade III obesity, with higher prevalence in males than in females (p < 0.001). Mean serum transaminases, in particular alanine aminotransferase (ALT), increased according to BMI and degree of steatosis. Homeostasis Model Assessment (HOMA) index, ferritin and fibrinogen levels increased with BMI, particularly in severe steatosis. In group 2, patients with BMI> or =40 showed a positive correlation between ferritin, aspartate aminotransferase (AST) (r = 0.46, p < 0.018), ALT (r = 0.41, p < 0.036) and gamma-glutamyltransferase (gammaGT) (r = 0.51, p < 0.007), between serum triglycerides (TG) and AST (r = 0.28, p < 0.036), ALT (r = 0.30, p < 0.02) and between HOMA and ALT (r = 0.30, p < 0.03) and gammaGT (r = 0.35, p < 0.012). In group 2 patients with severe steatosis the prevalence of metabolic syndrome according to Adult Treatment Panel III (ATP III) was 40%.

CONCLUSION

These data suggest that, in young adult non-diabetic grade III obese patients, fatty liver is always present and strictly related to insulin resistance which, in the presence of severe liver steatosis, is also related to serum ferritin.

The prediction of basal metabolic rate in young adult, severely obese patients using single-frequency bioimpedance analysis

To evaluate whether bioimpedance analysis (BIA) is a useful tool for predicting basal metabolic rate (BMR), sex, age, height, weight, BMI, and single-frequency BIA variables (resistance index and phase angle) were assessed in 61 young adult non-diabetic obese patients (BMI >35 kg/m(2)). BMR was measured by indirect calorimetry. In both sexes BMR significantly correlated with weight, BMI, and resistance index. Using multiple regression analysis, the following prediction equations were derived: (1). considering individual characteristics: BMR (kcal/day)=780+11.4xweight (+221 for men); (2). including also BIA variables: BMR=- 96+8.4xresistance index+8.3xweight+82.5xphase angle. Thus, in young adult, severely obese individuals, BIA variables are significant predictors of BMR.

Alteration in the ubiquitin structure and function in the human lens: a possible mechanism of senile cataractogenesis

High-performance liquid chromatography purification followed by mass spectrometry analyses highlighted that human senile cataractous lens includes a 8182 Da species which is absent in the normal lens, whereas a 8566/8583 Da species is present in both lenses. Western blot analysis identified both species as ubiquitin. The species at lower molecular weight is a shorter form due to the cleavage of the C-terminal residues 73-76. As it is the last amino acid of ubiquitin which is involved in the protein degradation mechanism, we suggest that this structure modification compromises the function of ubiquitin and consequently the physiologically occurring degradation of the lens proteins.

Overlapping between fluorescence modifications and activation of prostate transglutaminase induced by sodium dodecyl sulfate

The transglutaminase from rat coagulating gland secretion has been proposed as a new member of the transglutaminase family. Its basal activity is about 11-fold lower than those of other transglutaminases (e.g., the cytosolic tissue transglutaminase), but reaches levels comparable to those of other transglutaminases on addition of specific surfactant agents. There is no study devoted to understanding the molecular basis of this apparently anomalous activation, which is maximal at approximately 1.5 mM sodium dodecyl sulfate. We provide evidence that in the presence of this detergent modifications of the intrinsic fluorescence as well as energy transfer of the protein fluorescence to a micellar probe parallel the activation of the enzyme. As the sodium dodecyl sulfate concentration inducing maximal activation equals the critical micellar concentration, the biological activity of this transglutaminase appears to be modulated by the binding of micellar aggregates. In fact, the enzyme is modified by posttranslational modifications consisting of some lipid tails. At least two of these tails could act as aggregation nuclei of the enzyme with detergents. This behavior is different from that typical of molecular forms purified from other sources.