Increased Plasma Levels of Heme Oxygenase-1 in Human Brucellosis.

BACKGROUND: Brucellosis is associated with inflammation and the oxidative stress response. Heme oxygenase-1 (HO-1) is a cytoprotective stress-responsive enzyme that has anti-inflammatory and anti-oxidant effects. Nevertheless, the role of HO-1 in human brucellosis has not yet been studied. The aim of this study was to examine the plasma levels of HO-1 in patients with brucellosis and to evaluate the ability of plasma HO-1 levels as an auxiliary diagnosis, a severity predictor, and a monitor for brucellosis treatments. METHODS: A total of 75 patients with brucellosis were divided into the acute, subacute, chronic active, and chronic stable groups. An additional 20 volunteers were included as the healthy control group. The plasma HO-1 levels and other laboratory parameters were measured in all groups. Furthermore, the plasma levels of HO-1 in the acute group were compared before and after treatment. RESULTS: The plasma HO-1 levels were considerably increased in the acute (4.97 ± 3.55), subacute (4.98 ± 3.23), and chronic active groups (4.43 ± 3.00) with brucellosis compared to the healthy control group (1.03 ± 0.63) (p < 0.01). In the acute group, the plasma HO-1 levels in the post-treatment group (2.33 ± 2.39) were significantly reduced compared to the pre-treatment group (4.97 ± 3.55) (p < 0.01). On the other hand, the plasma HO-1 levels were higher in the chronic active group (4.43 ± 3.00) than the chronic stable group (2.74 ± 2.23) (p < 0.05). However, the plasma HO-1 levels in the chronic stable group (2.74 ± 2.23) remained higher than the levels in the healthy control group (1.03 ± 0.63) (p < 0.05). The HO-1 levels were positively correlated with the C-reactive protein (CRP) levels in patients with brucellosis (r = 0.707, p < 0.01). CONCLUSIONS: The plasma HO-1 levels can reflect patients' brucellosis status and may be used as a supplementary plasma marker for diagnosing brucellosis and monitoring its treatment.

Chronic ethanol consumption increases cardiomyocyte fatty acid uptake and decreases ventricular contractile function in C57BL/6J mice.

Alcohol, a major cause of human cardiomyopathy, decreases cardiac contractility in both animals and man. However, key features of alcohol-related human heart disease are not consistently reproduced in animal models. Accordingly, we studied cardiac histology, contractile function, cardiomyocyte long chain fatty acid (LCFA) uptake, and gene expression in male C57BL/6J mice consuming 0, 10, 14, or 18% ethanol in drinking water for 3months. At sacrifice, all EtOH groups had mildly decreased body and increased heart weights, dose-dependent increases in cardiac triglycerides and a marked increase in cardiac fatty acid ethyl esters. [(3)H]-oleic acid uptake kinetics demonstrated increased facilitated cardiomyocyte LCFA uptake, associated with increased expression of genes encoding the LCFA transporters CD36 and Slc27a1 (FATP1) in EtOH-fed animals. Although SCD-1 expression was increased, lipidomic analysis did not indicate significantly increased de novo LCFA synthesis. By echocardiography, ejection fraction (EF) and the related fractional shortening (FS) of left ventricular diameter during systole were reduced and negatively correlated with cardiac triglycerides. Expression of myocardial PGC-1α and multiple downstream target genes in the oxidative phosphorylation pathway, including several in the electron transport and ATP synthase complexes of the inner mitochondrial membrane, were down-regulated. Cardiac ATP was correspondingly reduced. The data suggest that decreased expression of PGC-1α and its target genes result in decreased cardiac ATP levels, which may explain the decrease in myocardial contractile function caused by chronic EtOH intake. This model recapitulates important features of human alcoholic cardiomyopathy and illustrates a potentially important pathophysiologic link between cardiac lipid metabolism and function.

Post-transcriptional activation of PPAR alpha by KLF6 in hepatic steatosis.

BACKGROUND & AIMS: Dysregulated glucose homeostasis and lipid accumulation characterize non-alcoholic fatty liver disease (NAFLD), but underlying mechanisms are obscure. We report here that Krüppel-like factor 6 (KLF6), a ubiquitous transcription factor that promotes adipocyte differentiation, also provokes the metabolic abnormalities of NAFLD by post-transcriptionally activating PPARα-signaling. METHODS: Mice with either hepatocyte-specific depletion of KLF6 ('ΔHepKlf6') or global KLF6 heterozygosity (Klf6+/-) were fed a high fat diet (HFD) or chow for 8 or 16 weeks. Glucose and insulin tolerance tests were performed to assess insulin sensitivity. Overexpression and knockdown of KLF6 in cultured cells enabled the elucidation of underlying mechanisms. In liver samples from a cohort of 28 NAFLD patients, the expression of KLF6-related target genes was quantified. RESULTS: Mice with global- or hepatocyte-depletion of KLF6 have reduced body fat content and improved glucose and insulin tolerance, and are protected from HFD-induced steatosis. In hepatocytes, KLF6 deficiency reduces PPARα-regulated genes (Trb3, Pepck) with diminished PPARα protein but no change in Pparα mRNA, which is explained by the discovery that KLF6 represses miRNA 10b, which leads to induction of PPARα. In NAFLD patients with advanced disease and inflammation, the expression of miRNA 10b is significantly downregulated, while PEPCK mRNA is upregulated; KLF6 mRNA expression also correlates with TRB3 as well as PEPCK gene expression. CONCLUSIONS: KLF6 increases PPARα activity, whereas KLF6 loss leads to PPARα repression and attenuation of lipid and glucose abnormalities associated with a high fat diet. The findings establish KLF6 as a novel regulator of hepatic glucose and lipid metabolism in fatty liver.

Mouse senile amyloid fibrils deposited in skeletal muscle exhibit amyloidosis-enhancing activity.

Amyloidosis describes a group of protein folding diseases in which amyloid proteins are abnormally deposited in organs and/or tissues as fine fibrils. Mouse senile amyloidosis is a disorder in which apolipoprotein A-II (apoA-II) deposits as amyloid fibrils (AApoAII) and can be transmitted from one animal to another both by the feces and milk excreted by mice with amyloidosis. Thus, mouse AApoAII amyloidosis has been demonstrated to be a "transmissible disease". In this study, to further characterize the transmissibility of amyloidosis, AApoAII amyloid fibrils were injected into transgenic Apoa2(c)Tg(+/-) and normal R1.P1-Apoa2(c) mice to induce AApoAII systemic amyloidosis. Two months later, AApoAII amyloid deposits were found in the skeletal muscles of amyloid-affected mice, primarily in the blood vessels and in the interstitial tissues surrounding muscle fibers. When amyloid fibrils extracted from the skeletal muscles were subjected to Western blot analysis, apoA-II was detected. Amyloid fibril fractions isolated from the muscles not only demonstrated the structure of amyloid fibrils but could also induce amyloidosis in young mice depending on its fibril conformation. These findings present a possible pathogenesis of amyloidosis: transmission of amyloid fibril conformation through muscle, and shed new light on the etiology involved in amyloid disorders.

Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease.

AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine.HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction.

Insulin- and leptin-regulated fatty acid uptake plays a key causal role in hepatic steatosis in mice with intact leptin signaling but not in ob/ob or db/db mice.

Hepatic steatosis results from several processes. To assess their relative roles, hepatocellular long-chain fatty acid (LCFA) uptake was assayed in hepatocytes from C57BL/6J control mice, mice with steatosis from a high-fat diet (HFD) or 10%, 14%, or 18% ethanol (EtOH) in drinking water [functioning leptin-signaling groups (FLSGs)], and ob/ob and db/db mice. V(max) for uptake was increased vs. controls (P < 0.001) and correlated significantly with liver weight and triglycerides (TGs) in all FLSG mice but was minimally or not increased in ob/ob and db/db mice, in which liver weights and TGs greatly exceeded projections from regressions in FLSG animals. Coefficients of determination (R(2)) for these FLSG regressions suggest that increased LCFA uptake accounts for ∼80% of the increase in hepatic TGs within these groups, but increased lipogenic gene expression data suggest that enhanced LCFA synthesis is the major contributor in ob/ob and db/db. Got2, Cd36, Slc27a2, and Slc27a5 gene expression ratios were significantly upregulated in the EtOH groups, correlating with sterol regulatory element binding protein 1c (SREBP1c) and V(max), but only Cd36 expression was increased in HFD, ob/ob, and db/db mice. Comparison of V(max) with serum insulin and leptin suggests that both hormones contribute to upregulation of uptake in the FLSG animals. Thus, increased LCFA uptake, reflecting SREBP1c-mediated upregulation of four distinct transporters, is the dominant cause of steatosis in EtOH-fed mice. In ob/ob and db/db mice, increased LCFA synthesis appears more important. In FLSG animals, insulin upregulates hepatocellular LCFA uptake. Leptin appears to upregulate LCFA uptake or to be essential for full expression of upregulation by insulin.

Characterization of the cheetah serum amyloid A1 gene: critical role and functional polymorphism of a cis-acting element.

Amyloid A (AA) amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction. For practical conservation of this species, therefore, it is critical to elucidate the etiology of AA amyloidosis, especially to understand the mechanisms of transcriptional regulation of serum amyloid A (SAA), a precursor protein of the AA protein. In this study, the structure and nucleotide sequence of the cheetah SAA1 gene including the 5'-flanking promoter/enhancer region was determined. Putative nuclear factor kappa-B (NF-kappaB) and CCAAT/enhancer binding protein beta (C/EBPbeta) cis-acting elements, which play key roles in SAA1 transcriptional induction in response to inflammation, were identified in the 5'-flanking region of the cheetah SAA1 gene. Fortuitously, a single nucleotide polymorphism was identified in the captive cheetah cohort in the putative NF-kappaB cis-acting element and had a remarkable effect on SAA1 transcriptional induction. These results provide a foundation not only for clarifying the etiology of AA amyloidosis in the cheetah but also for contriving a strategy for conservation of this species.

Facilitated long chain fatty acid uptake by adipocytes remains upregulated relative to BMI for more than a year after major bariatric surgical weight loss.

OBJECTIVE: This study examined whether changes in adipocyte long chain fatty acid (LCFA) uptake kinetics explain the weight regain increasingly observed following bariatric surgery. METHODS: Three groups (10 patients each) were studied: patients without obesity (NO: BMI 24.2 ± 2.3 kg m(-2) ); patients with obesity (O: BMI 49.8 ± 11.9); and patients classified as super-obese (SO: BMI 62.6 ± 2.8). NO patients underwent omental and subcutaneous fat biopsies during clinically indicated abdominal surgeries; O were biopsied during bariatric surgery, and SO during both a sleeve gastrectomy and at another bariatric operation 16 ± 2 months later, after losing 113 ± 13 lbs. Adipocyte sizes and [(3) H]-LCFA uptake kinetics were determined in all biopsies. RESULTS: Vmax for facilitated LCFA uptake by omental adipocytes increased exponentially from 5.1 ± 0.95 to 21.3 ± 3.20 to 68.7 ± 9.45 pmol/sec/50,000 cells in NO, O, and SO patients, respectively, correlating with BMI (r = 0.99, P < 0.001). Subcutaneous results were virtually identical. By the second operation, the mean BMI (SO patients) fell significantly (P < 0.01) to 44.4 ± 2.4 kg m(-2) , similar to the O group. However, Vmax (40.6 ± 11.5) in this weight-reduced group remained ~2X that predicted from the BMI:Vmax regression among NO, O, and SO patients. CONCLUSIONS: Facilitated adipocyte LCFA uptake remains significantly upregulated ≥1 year after bariatric surgery, possibly contributing to weight regain.

Spexin is a novel human peptide that reduces adipocyte uptake of long chain fatty acids and causes weight loss in rodents with diet-induced obesity.

OBJECTIVE: Microarray studies identified Ch12:orf39 (Spexin) as the most down-regulated gene in obese human fat. Therefore, we examined its role in obesity pathogenesis. METHODS: Spexin effects on food intake, meal patterns, body weight, respiratory exchange ratio (RER), and locomotor activity were monitored electronically in C57BL/6J mice or Wistar rats with diet-induced obesity (DIO). Its effects on adipocyte [(3)H]-oleate uptake were determined. RESULTS: In humans, Spexin gene expression was down-regulated 14.9-fold in obese omental and subcutaneous fat. Circulating Spexin changed in parallel, correlating (r = -0.797) with Leptin. In rats, Spexin (35 µg/kg/day SC) reduced caloric intake ∼32% with corresponding weight loss. Meal patterns were unaffected. In mice, Spexin (25 µg/kg/day IP) significantly reduced the RER at night, and increased locomotion. Spexin incubation in vitro significantly inhibited facilitated fatty acid (FA) uptake into DIO mouse adipocytes. Conditioned taste aversion testing (70 µg/kg/day IP) demonstrated no aversive Spexin effects. CONCLUSIONS: Spexin gene expression is markedly down-regulated in obese human fat. The peptide produces weight loss in DIO rodents. Its effects on appetite and energy regulation are presumably central; those on adipocyte FA uptake appear direct and peripheral. Spexin is a novel hormone involved in weight regulation, with potential for obesity therapy.

Cardiomyocyte triglyceride accumulation and reduced ventricular function in mice with obesity reflect increased long chain Fatty Acid uptake and de novo Fatty Acid synthesis.

A nonarteriosclerotic cardiomyopathy is increasingly seen in obese patients. Seeking a rodent model, we studied cardiac histology, function, cardiomyocyte fatty acid uptake, and transporter gene expression in male C57BL/6J control mice and three obesity groups: similar mice fed a high-fat diet (HFD) and db/db and ob/ob mice. At sacrifice, all obesity groups had increased body and heart weights and fatty livers. By echocardiography, ejection fraction (EF) and fractional shortening (FS) of left ventricular diameter during systole were significantly reduced. The V(max) for saturable fatty acid uptake was increased and significantly correlated with cardiac triglycerides and insulin concentrations. V(max) also correlated with expression of genes for the cardiac fatty acid transporters Cd36 and Slc27a1. Genes for de novo fatty acid synthesis (Fasn, Scd1) were also upregulated. Ten oxidative phosphorylation pathway genes were downregulated, suggesting that a decrease in cardiomyocyte ATP synthesis might explain the decreased contractile function in obese hearts.