Impaired Hepatic Mitochondrial Capacity in Nonalcoholic Steatohepatitis Associated With Type 2 Diabetes

OBJECTIVE

Individuals with type 2 diabetes are at higher risk of progression of nonalcoholic fatty liver (steatosis) to steatohepatitis (NASH), fibrosis, and cirrhosis. The hepatic metabolism of obese individuals adapts by upregulation of mitochondrial capacity, which may be lost during the progression of steatosis. However, the role of type 2 diabetes with regard to hepatic mitochondrial function in NASH remains unclear.

RESEARCH DESIGN AND METHODS

We therefore examined obese individuals with histologically proven NASH without (OBE) (n = 30; BMI 52 ± 9 kg/m2) or with type 2 diabetes (T2D) (n = 15; 51 ± 7 kg/m2) as well as healthy individuals without liver disease (CON) (n = 14; 25 ± 2 kg/m2). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamps with d-[6,6-2H2]glucose. Liver biopsies were used for assessing mitochondrial capacity by high-resolution respirometry and protein expression.

RESULTS

T2D and OBE had comparable hepatic fat content, lobular inflammation, and fibrosis. Oxidative capacity in liver tissue normalized for citrate synthase activity was 59% greater in OBE than in CON, whereas T2D presented with 33% lower complex II-linked oxidative capacity than OBE and higher H2O2 production than CON. Interestingly, those with NASH and hepatic fibrosis score ≥1 had lower oxidative capacity and antioxidant defense than those without fibrosis.

CONCLUSIONS

Loss of hepatic mitochondrial adaptation characterizes NASH and type 2 diabetes or hepatic fibrosis and may thereby favor accelerated disease progression.

An evaluation procedure for flocculation of coal preparation plant tailings

In solid-liquid separation of coal preparation plant tailings by flocculation, in addition to the type and amount of flocculants, the composition of waste materials including clay minerals must be determined in order to devise an effective and economic sedimentation system. In this study, the characterization of organic and inorganic impurities was made with the help of mineralogical data and instrumental analysis techniques. The effects of polymer type (medium and low anionic, cationic and nonionic), polymer dosage and suspension pH on flocculation mechanism of tailings particles (-0.18 mm) in the Tunçbilek Coal Preparation Plant tailings of Tunçbilek (Turkey) were investigated. Medium anionic polymer accelerated the settling rate of particles. An optimum settling rate (300 mm/min) was reached at a dosage rate of 34.19 g/ton-solids (2.0 mg/l), 51.28 g/ton-solids (3.0 mg/l), 102.56 g/ton-solids (6.0 mg/l) and 119.66 g/ton-solids (7.0mg/l) for medium anionic, low charged anionic, nonionic and cationic polymers, respectively. The lowest turbidity values at low polymer dosages were obtained by the cationic polymer at around 25.64 g/ton-solids (1.5 mg/l) polymer dosages; however, the low anionic and nonionic polymers produced lower turbidity values at higher dosages (>25.64 g/ton-solids). At optimum dosages of the polymer, the settling rate decreased at low and high pHs indicating that the natural pH (pH 8.3) of the suspension is the most appropriate pH for the settling rate. On the other hand, the water clarity values at natural pHs were high for all of the polymers.

Adsorption of cobalt from aqueous solutions onto sepiolite

Adsorption of Co(II) ions from aqueous sepiolite suspensions has been systematically investigated as a function of several variables including activation conditions, solid to liquid ratio, pH and temperature. The results are analyzed to identify the mechanism of cobalt uptake by sepiolite. Both abstraction and real adsorption isotherms were constructed to isolate the precipitation of cobalt from the real adsorption. Also, for the first time a plausible correlation between the released Mg(II) ions from sepiolite matrix and those adsorbed Co(II) ions is made. A one to one ion exchange mechanism is found to describe the results. The data obtained from adsorption isotherms at different temperatures were fitted to various adsorption models to calculate thermodynamic quantities such as the free energy of adsorption, heat of adsorption and entropy of adsorption. The thermodynamic data indicate that Co(II) adsorption onto sepiolite is entropically driven and characterized by physical adsorption.

Adsorption mechanism of cationic surfactants onto acid- and heat-activated sepiolites

Systematic adsorption tests were carried out to determine the uptake of typical quaternary amines, dodecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide and a primary amine, dodecylamine hydrochloride by sepiolite. Bottle adsorption tests conducted with untreated, acid- and heat-activated sepiolites exhibit two distinct regions. The first stage is characterized by low rate and governed through an ion exchange process between ammonium ions and magnesium ions in the octahedral sheet. The second stage is ascribed to a combination of chain-chain interactions through Van der Waals forces and ion exchange process. Despite several-fold increases in surface areas upon activation, surprisingly no improvement in adsorption is observed. The observed differences are explained on the basis of partial collapse of the sepiolite crystal structure, the removal of zeolitic and bound waters and modification of the pore size distribution of sepiolite upon treatments.

Interaction of Pyridine Derivatives with Sepiolite

In this study, the adsorption behavior of pyridine derivatives, i.e., 2-aminopyridine and 2,2'-bipyridyl, onto sepiolite, a natural clay mineral, has been investigated by bottle adsorption and IR spectroscopic techniques. The results indicate that 2-aminopyridine and 2,2'-bipyridyl molecules adsorb onto sepiolite through hydrogen bonding of the amino groups to the water molecules in the octahedral sheet and to the surface hydroxyls (Si-OH) in the tetrahedral sheet. These findings reveal that pyridine molecules not only adsorb onto the external surface of sepiolite but are also incorporated in its channels and tunnels with adsorption taking place at corners and/or edges, depending on the position of water molecules. A structural model is proposed to account for the orientation of pyridine derivatives in the sepiolite matrix.

Effect of chewing gum on plaque acidogenicity

The aim of this investigation was to study the effect of chewing sucrose-containing gum, xylitol-sorbitol-containing gum and natural gum (Pistacia lenticus) on the pH recovery of sucrose challenged dental plaque. Plaque pH was measured by microtouch electrode method on two-days old plaque. The results of the present study suggest that the chewing gum increases plaque pH. Chewing natural gum created the highest plaque pH values.

Odontodysplasia: report of a case

A case of generalized odontodysplasia in a nine year-5-month old male patient is presented. Clinical and radiological characteristics of this developmental anomaly and treatment is described. The distribution of affected teeth in all four quadrants suggests that genetic transmission or a somatic mutation may be the causative factor.