Extrahepatic Tissues Research Articles

The nuclear sirtuin SIRT6 plays a role in regulating cardiac branched‐chain amino acid catabolism

IntroductionTo derive energy, heart uses multiple substrates such as fatty acids, glucose, amino acids, ketones and lactic acid. Defective catabolism of branched‐chain amino acids (BCAAs), which include valine, leucine and isoleucine, is implicated in coronary heart disease and in cardiac ischemia‐reperfusion injury. BCAAs are primarily catabolized in extra‐hepatic tissues, which include muscle, kidney, brain and adipose. Enzymes involved in BCAA catabolism are highly expressed in the heart. Abnormal elevation in BCAA‐levels is linked to impaired lipid metabolism, development of insulin‐resistance and suppression of glucose metabolism. Increased levels of BCAAs in plasma and urine are considered as a better indicator of the pre‐diabetic state with impaired insulin sensitivity. Under physiological conditions, BCAAs maintain glucose homeostasis by stimulating insulin secretion. The NAD+‐dependent enzyme, SIRT6 plays a critical role to maintain cellular glucose and lipid homeostasis. This chromatin‐bound sirtuin is a key epigenetic regulator of glucose homeostasis. This study was undertaken to explore the role of SIRT6 in BCAA metabolism in the heart tissue.Methods and ResultsRNAseq analysis of the heart tissue from wild type and global SIRT6 knockout mice revealed that the expression of genes regulating BCAA catabolism were significantly affected with loss of SIRT6. We also investigated expression of the genes of BCAA pathway, in neonatal rat cardiomyocytes infected for 72 hours with adenoviruses for null or rat SIRT6‐shRNA‐(KO) or for human SIRT6‐over‐expression. The expression of RNA in these cells was measured by RNAseq and qPCR analyses, and proteins by western blotting. SIRT6 deficiency in cardiomyocytes and in the heart tissue resulted in a general downregulation of the genes involved in BCAA catabolism. One of the rate‐limiting step in BCAA catabolism is decarboxylation of Branched‐chain α‐keto acid (BCKA), which is catalyzed by the BCK‐dehydrogenase (BCKDH) complex. The BCKDH complex is activated by dephosphorylation by the phosphatase Pp2cm (Ppm1k). In the mouse and human failing hearts, Ppm1k deficiency has been linked to dysfunctional BCAA catabolism. We found nearly 2 fold downregulation of Ppm1k in SIRT6‐deficient hearts and cardiomyocytes, however, no change was observed in expression of other enzymes of the BCKDH complex. Interestingly, with SIRT6 over‐expression in cardiomyocytes, gene expression of other members of the BCAA catabolism pathway, including Ppm1K, was restored to normalcy. These results were confirmed by RT‐qPCR analysis of the heart tissue. Moreover, we found that the promoter for Ppm1k gene harbors binding sites for NF‐κB p65 and c‐Jun transcription factors, which are known targets for SIRT6.ConclusionOur results indicate that SIRT6 transcriptionally regulates the BCAA catabolic pathway in the mouse heart, and its loss could contribute to development of heart failure.Support or Funding InformationNIH RO1 HL136712, NIH RO1 HL143488

Selective organ targeting (SORT) nanoparticles for tissue-specific mRNA delivery and CRISPR-Cas gene editing.

CRISPR/Cas gene editing and messenger RNA (mRNA)-based protein replacement therapy hold tremendous potential to effectively treat disease-causing mutations with diverse cellular origin. However, it is currently impossible to rationally design nanoparticles that selectively target specific tissues. Here, we report a strategy termed Selective ORgan Targeting (SORT) wherein multiple classes of lipid nanoparticles (LNPs) are systematically engineered to exclusively edit extrahepatic tissues via addition of a supplemental SORT molecule. Lung-, spleen-, and liver-targeted SORT LNPs were designed to selectively edit therapeutically relevant cell types including epithelial cells, endothelial cells, B cells, T cells, and hepatocytes. SORT is compatible with multiple gene editing techniques, including mRNA, Cas9 mRNA / sgRNA, and Cas9 ribonucleoprotein (RNP) complexes, and is envisioned to aid development of protein replacement and gene correction therapeutics in targeted tissues.

Timing in drug absorption and disposition: The past, present, and future of chronopharmacokinetics.

The importance of drug dosing time in pharmacokinetics, pharmacodynamics, and toxicity is receiving increasing attention from the scientific community. In spite of mounting evidence that circadian oscillations affect drug absorption, distribution, metabolism, and excretion (ADME), there remain many unanswered questions in this field and, occasionally, conflicting experimental results. Such data arise not only from translational difficulties caused by interspecies differences but also from variability in study design and a lack of understanding of how the circadian clock affects physiological factors that strongly influence ADME, namely, the expression and activity of drug transporters. Hence, the main goal of this review is to provide an updated analysis of the role of the circadian rhythm in drug absorption, distribution across blood-tissue barriers, metabolism in hepatic and extra-hepatic tissues, and hepatobiliary and renal excretion. It is expected that the research suggestions proposed here will contribute to a tissue-targeted and time-targeted pharmacotherapy.

Ubiquitous antigen-specific T regulatory type 1 cells variably suppress hepatic and extrahepatic autoimmunity

Peptide MHC class II-based (pMHCII-based) nanomedicines trigger the formation of multicellular regulatory networks by reprogramming autoantigen-experienced CD4+ T cells into autoimmune disease-suppressing T regulatory type 1 (TR1) cells. We have shown that pMHCII-based nanomedicines displaying liver autoimmune disease-relevant yet ubiquitously expressed antigens can blunt various liver autoimmune disorders in a non-disease-specific manner without suppressing local or systemic immunity against infectious agents or cancer. Here, we show that such ubiquitous autoantigen-specific T cells are also awakened by extrahepatic tissue damage and that the corresponding TR1 progeny can suppress experimental autoimmune encephalomyelitis (EAE) and pancreatic β cell autoreactivity. In mice having EAE, nanomedicines displaying either ubiquitous or CNS-specific epitopes triggered the formation and expansion of cognate TR1 cells and their recruitment to the CNS-draining lymph nodes, sparing their liver-draining counterparts. Surprisingly, in mice having both liver autoimmunity and EAE, liver inflammation sequestered these ubiquitous or even CNS-specific TR1 cells away from the CNS, abrogating their antiencephalitogenic activity. In these mice, only the ubiquitous antigen-specific TR1 cells suppressed liver autoimmunity. Thus, the scope of antigen spreading in autoimmune disorders is larger than previously anticipated, involving specificities expected to be silenced by mechanisms of tolerance; the regulatory activity, but not the retention of autoreactive TR1 cells, requires local autoantigen expression.

Hepatocyte Injury and Hepatic Stem Cell Niche in the Progression of Non-Alcoholic Steatohepatitis.

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by lipid accumulation in hepatocytes in the absence of excessive alcohol consumption. The global prevalence of NAFLD is constantly increasing. NAFLD is a disease spectrum comprising distinct stages with different prognoses. Non-alcoholic steatohepatitis (NASH) is a progressive condition, characterized by liver inflammation and hepatocyte ballooning, with or without fibrosis. The natural history of NAFLD is negatively influenced by NASH onset and by the progression towards advanced fibrosis. Pathogenetic mechanisms and cellular interactions leading to NASH and fibrosis involve hepatocytes, liver macrophages, myofibroblast cell subpopulations, and the resident progenitor cell niche. These cells are implied in the regenerative trajectories following liver injury, and impairment or perturbation of these mechanisms could lead to NASH and fibrosis. Recent evidence underlines the contribution of extra-hepatic organs/tissues (e.g., gut, adipose tissue) in influencing NASH development by interacting with hepatic cells through various molecular pathways. The present review aims to summarize the role of hepatic parenchymal and non-parenchymal cells, their mutual influence, and the possible interactions with extra-hepatic tissues and organs in the pathogenesis of NAFLD.

Extrahepatic deficiency of transferrin receptor 2 is associated with increased erythropoiesis independent of iron overload

Transferrin receptor 2 (TFR2) is a transmembrane protein expressed mainly in hepatocytes and in developing erythroid cells and is an important focal point in systemic iron regulation. Loss of TFR2 function results in a rare form of the iron-overload disease hereditary hemochromatosis. Although TFR2 in the liver has been shown to be important for regulating iron homeostasis in the body, TFR2's function in erythroid progenitors remains controversial. In this report, we analyzed TFR2-deficient mice in the presence or absence of iron overload to distinguish between the effects caused by a high iron load and those caused by loss of TFR2 function. Analysis of bone marrow from TFR2-deficient mice revealed a reduction in the early burst-forming unit-erythroid and an expansion of late-stage erythroblasts that was independent of iron overload. Spleens of TFR2-deficient mice displayed an increase in colony-forming unit-erythroid progenitors and in all erythroblast populations regardless of iron overload. This expansion of the erythroid compartment coincided with increased erythroferrone (ERFE) expression and serum erythropoietin (EPO) levels. Rescue of hepatic TFR2 expression normalized hepcidin expression and the total cell count of the bone marrow and spleen, but it had no effect on erythroid progenitor frequency. On the basis of these results, we propose a model of TFR2's function in murine erythropoiesis, indicating that deficiency in this receptor is associated with increased erythroid development and expression of EPO and ERFE in extrahepatic tissues independent of TFR's role in the liver.

Serum amyloid A exhibits pH dependent antibacterial action and contributes to host defense against Staphylococcus aureus cutaneous infection

Serum amyloid A (SAA), one of the major highly conserved acute-phase proteins in most mammals, is predominantly produced by hepatocytes and also by a variety of cells in extrahepatic tissues. It is well-known that the expression of SAA is sharply increased in bacterial infections. However, the exact physiological function of SAA during bacterial infection remains unclear. Herein, we showed that SAA expression significantly increased in abscesses of Staphylococcus aureus cutaneous infected mice, which exert direct antibacterial effects by binding to the bacterial cell surface and disrupting the cell membrane in acidic conditions. Mechanically, SAA disrupts anionic liposomes by spontaneously forming small vesicles or micelles under acidic conditions. Especially, the N-terminal region of SAA is necessary for membrane disruption and bactericidal activity. Furthermore, we found that mice deficient in SAA1/2 were more susceptible to infection by S. aureus In addition, the expression of SAA in infected skin was regulated by interleukin-6. Taken together, these findings support a key role of the SAA in host defense and may provide a novel therapeutic strategy for cutaneous bacterial infection.

African walnuts attenuate ectopic fat accumulation and associated peroxidation and oxidative stress in monosodium glutamate-obese Wistar rats

AimsAfrican walnuts were previously shown to modulate hepatic lipid bio-accumulation in obesity. Herein, we investigated the impact of the nuts on fat accumulation in adipose and ectopic regions, and associated oxidatiive stress status in obese rats. Materials and methodsWhole ethanol extract (WE) of the nuts, and its liquid-liquid fractions-ethyl acetate (ET) and residue (RES) were separately administered to obese rats for 6 weeks. The normal (NC) and obese (OC) controls received normal saline and the standard control (SC), orlistat (5.14 mg/kg b.w.), during the same period. Thereafter, the animals were euthanized and the adipose, brain, kidneys and heart tissues were studied. ResultsThe change in body weight to naso-anal length which increased by 63.52 % in OC compared to NC (p < 0.05), decreased by 57.88, 85.80 and 70.20 % in WE, ET and RES-treated groups, respectively, relative to the OC (p < 0.05). Also, adipose tissue weights were lowered upon treatment with the extracts and fractions versus OC (p < 0.05). Total lipids, phospholipids, triacylglycerol and cholesterol concentrations in the studied tissues which were higher in OC (p < 0.05) were lowered (p < 0.05) and compared favorably with SC. Further, malondialdehyde levels in the tissues were lowered upon treatment, compared to the OC (p < 0.05). Glutathione level and activities of glutathione peroxidase, superoxide dismutase and glutathione-S-transferase which were decreased (p < 0.05) in OC, were restored upon treatment with the extracts, relative to the obese control (p < 0.05). SignificanceAfrican walnuts assuaged lipogenesis, oxidative stress and peroxidation in extra-hepatic tissues of obese rats, hence, may attenuate ectopic fat accumulation and its associated pathogenesis.

Iron-induced derangement in hepatic Δ-5 and Δ-6 desaturation capacity and fatty acid profile leading to steatosis: Impact on extrahepatic tissues and prevention by antioxidant-rich extra virgin olive oil

The administration of iron induces liver oxidative stress and depletion of long-chain polyunsaturated fatty acids (LCPUFAs), n-6/n-3 LCPUFA ratio enhancement and fat accumulation, which may be prevented by antioxidant-rich extra virgin olive oil (AR-EVOO) supplementation. Male Wistar rats were subjected to a control diet (50 mg iron/kg diet) or iron-rich diet (IRD; 200 mg/kg diet) with alternate AR-EVOO for 21 days. Liver fatty acid (FA) analysis was performed by gas-liquid chromatography (GLC) after lipid extraction and fractionation, besides Δ-5 desaturase (Δ-5 D) and Δ6-D mRNA expression (qPCR) and activity (GLC) measurements. The IRD significantly (p < 0.05) increased hepatic total fat, triacylglycerols, free FA contents and serum transaminases levels, with diminution in those of n-6 and n-3 LCPUFAs, higher n-6/n-3 ratios, lower unsaturation index and Δ5-D and Δ6-D activities, whereas the mRNA expression of both desaturases was enhanced over control values, changes that were prevented by concomitant AR-EVOO supplementation. N-6 and n-3 LCPUFAs were also decreased by IRD in extrahepatic tissues and normalized by AR-EVOO. In conclusion, AR-EVOO supplementation prevents IRD-induced changes in parameters related to liver FA metabolism and steatosis, an effect that may have a significant impact in the treatment of iron-related pathologies or metabolic disorders such as non-alcoholic fatty liver disease.

Fibrin(ogen) in human disease: both friend and foe

Fibrinogen is an abundant protein synthesized in the liver, present in human blood plasma at concentrations ranging from 1.5-4 g/L in healthy individuals with a normal half-life of 3-5 days. With fibrin, produced by thrombin-mediated cleavage, fibrinogen plays important roles in many physiological processes. Indeed, the formation of a stable blood clot, containing polymerized and cross-linked fibrin, is crucial to prevent blood loss and drive wound healing upon vascular injury. A balance between clotting, notably the conversion of fibrinogen to fibrin, and fibrinolysis, the proteolytic degradation of the fibrin mesh, is essential. Disruption of this equilibrium can cause disease in distinct manners. While some pathological conditions are the consequence of altered levels of fibrinogen, others are related to structural properties of the molecule. The source of fibrinogen expression and the localization of fibrin(ogen) protein also have clinical implications. Low levels of fibrinogen expression have been detected in extra-hepatic tissues, including carcinomas, potentially contributing to disease. Fibrin(ogen) deposits at aberrant sites including the central nervous system or kidney, can also be pathological. In this review, we discuss disorders in which fibrinogen and fibrin are implicated, highlighting mechanisms that may contribute to disease.

Interaction of Oatp1b2 expression and nonalcoholic steatohepatitis on pravastatin plasma clearance

The downregulation of hepatic uptake transporters, including those of the OATP family, are a well known consequence of nonalcoholic steatohepatitis (NASH). Prior studies have shown that the combination of NASH and Oatp1b2 knockout synergistically reduces the clearance of pravastatin (PRAV) in the methionine and choline deficient (MCD) mouse model of NASH, and the current study therefore aimed to determine the impact of NASH and genetic heterozygosity of Oatp1b2 on PRAV clearance, modeling the overlap between the 24% of the human population who are heterozygous for non-functioning OATP1B1, and the ~15% with NASH, potentially placing these people at higher risk of statin-induced myopathy. Therefore, male C57BL/6 wild-type (WT), Oatp1b2+/− (HET), and Oatp1b2−/− (KO) mice were fed either a control (methionine and choline sufficient) or methionine and choline-deficient (MCD) diet to induce NASH. After six weeks of feeding, pravastatin was administered via the carotid artery. Blood and bile samples were collected throughout 90 min after PRAV administration. The concentration of PRAV in plasma, bile, liver, kidney, and muscle was determined by liquid chromatography-tandem mass spectrometry. MCD diet did not alter the plasma AUC values of PRAV in either WT or HET mice. However, the MCD diet increased plasma AUC by 4.4-fold in KO mice. MCD diet and nonfunctional Oatp1b2 synergistically increased not only plasma AUC but also the extrahepatic tissue concentration of pravastatin, whereas the partially decreased function of Oatp1b2 and NASH together were insufficient in significantly altering PRAV pharmacokinetics. These data suggest that a single copy of fully functional OATP1B1 in NASH patients may be sufficient to avoid the increase of pravastatin toxicity.

UDP-Glycosyltransferase 3A Metabolism of Polycyclic Aromatic Hydrocarbons: Potential Importance in Aerodigestive Tract Tissues.

Polycyclic aromatic hydrocarbons (PAHs) are potent carcinogens and are a primary risk factor for the development of lung and other aerodigestive tract cancers in smokers. The detoxification of PAHs by glucuronidation is well-characterized for the UDP-glycosyltransferase (UGT) 1A, 2A, and 2B subfamilies; however, the role of the UGT3A subfamily in PAH metabolism remains poorly understood. UGT3A enzymes are functionally distinct from other UGT subfamilies (which use UDP-glucuronic acid as a cosubstrate) due to their utilization of alternative cosubstrates (UDP-N-acetylglucosamine for UGT3A1, and UDP-glucose and UDP-xylose for UGT3A2). The goal of the present study was to characterize UGT3A glycosylation activity against PAHs and examine their expression in human aerodigestive tract tissues. In vitro metabolism assays using UGT3A2-overexpressing cell microsomes indicated that UGT3A2 exhibits glycosylation activity against all of the simple and complex PAHs tested. The Vmax/Km ratios for UGT3A2 activity with UDP-xylose versus UDP-glucose as the cosubstrate ranged from 0.65 to 4.4 for all PAHs tested, demonstrating that PAH glycosylation may be occurring at rates up to 4.4-fold higher with UDP-xylose than with UDP-glucose. Limited glycosylation activity was observed against PAHs with UGT3A1-overexpressing cell microsomes. While UGT3A2 exhibited low levels of hepatic expression, it was shown by western blot analysis to be widely expressed in aerodigestive tract tissues. Conversely, UGT3A1 exhibited the highest expression in liver with lower expression in aerodigestive tract tissues. These data suggest that UGT3A2 plays an important role in the detoxification of PAHs in aerodigestive tract tissues, and that there may be cosubstrate-dependent differences in the detoxification of PAHs by UGT3A2.SIGNIFICANCE STATEMENTUGT3A2 is highly active against PAHs with either UDP-glucose or UDP-xylose as a cosubstrate. UGT3A1 exhibited low levels of activity against PAHs. UGT3A1 is highly expressed in liver while UGT3A2 is well expressed in extrahepatic tissues. UGT3A2 may be an important detoxifier of PAHs in humans.

Association of CYP2J2 polymorphism with susceptibility to psoriasis in Turkish population: a case–control study

BackgroundCytochrome P450 2J2 is mostly expressed in extrahepatic tissues; it metabolizes arachidonic acid to epoxyeicosatrienoic acids, with various cardio protective and anti-inflammatory effects. CYP2J2 polymorphism has been identified as a risk factor for cardiovascular diseases, but its association with psoriasis remains unknown. ObjectiveTo evaluate CYP2J2 polymorphism as a risk factor for psoriasis in the Turkish population. MethodsThere were 94 patients with psoriasis and 100 age- and sex-matched healthy controls included in the study. Detailed demographic and clinical characteristics were recorded, and Psoriasis Area and Severity Index (PASI) scores were calculated for psoriasis patients. Venous blood samples were collected from all the participants and CYP2J2 50G>T (rs890293) polymorphism was analyzed using polymerase chain reaction (PCR). ResultsBoth T allele and TT+GT genotype frequencies were increased in psoriasis vulgaris patients compared to the control group (p=0.024 and p=0.029 respectively, OR=2.82, 95% CI: 1.11–7.15) No association between CYP2J2 polymorphism and clinical features of psoriasis was identified. Study limitationsA limited number of patients were included in the study. ConclusionCYP2J2 50G>T (rs890293) polymorphism was associated with an increased risk for PsV in the Turkish population.

A low-carbohydrate ketogenic diet induces the expression of very-low-density lipoprotein receptor in liver and affects its associated metabolic abnormalities

A low-carbohydrate ketogenic diet (LCKD) promotes the progression of hepatic steatosis in C57BL/6 wild-type mice, but improves the condition in leptin-deficient obese (ob/ob) mice. Here, we show a novel effect of LCKD associated with the conflicting effects on these mice. Gene expression microarray analyses showed that expression of the Vldlr gene, which encodes the very-low-density lipoprotein receptor (VLDLR), was induced in LCKD-fed ob/ob mice. Although the VLDLR is not normally expressed in the liver, the LCKD led to VLDLR expression in both ob/ob and wild-type mice. To clarify this effect on VLDL dynamics, we analyzed the lipid content of serum lipoproteins and found a marked decrease in VLDL-triglycerides only in LCKD-fed wild-type mice. Further analyses suggested that transport of triglycerides via VLDL from the liver to extrahepatic tissues was inhibited by LCKD-induced hepatic VLDLR expression, but rescued under conditions of leptin deficiency.

Widespread basal cytochrome P450 expression in extrahepatic bovine tissues and isolated cells

Periparturient cattle face increased risk of both metabolic and infectious diseases. Factors contributing to this predisposition include oxidized polyunsaturated fatty acids, also known as oxylipids, whose production is altered during the periparturient period and in diseased cattle. Alterations in the production of oxylipids derived from cytochrome P450 (CYP450) enzymes are over-represented during times of increased disease risk and clinical disease, such as mastitis. Many of these same CYP450 enzymes additionally regulate metabolism of fat-soluble vitamins, such as A, D, and E. These vitamins are essential to maintaining immune health, yet circulating concentrations are diminished near calving. Despite this, a relatively small amount of research has focused on the roles of CYP450 enzymes outside of the liver. The aim of this paper is to describe the relative gene expression of 11 CYP450 in bovine tissues and common in vitro bovine cell models. Eight tissue samples were collected from 3 healthy dairy cows after euthanasia. In vitro samples included primary bovine aortic and mammary endothelial cells and immortalized bovine kidney and mammary epithelial cells. Quantitative real-time-PCR was carried out to assess basal transcript expression of CYP450 enzymes. Surprisingly, CYP450 mRNA was widely expressed in all tissue samples, with predominance in the liver. In vitro CYP450 expression was less robust, with several cell types lacking expression of specific CYP450 enzymes altogether. Overall, cell culture models did not reflect expression of tissue CYP450. However, when CYP450 were organized by activity, certain cell types consistently expressed specific functional groups. These data reveal the widespread expression of CYP450 in individual organs of healthy dairy cows. Widespread expression helps to explain previous evidence of significant changes in CYP450-mediated oxylipid production and fat-soluble vitamin metabolism in organ microenvironments during periods of oxidative stress or disease. As such, these data provide a foundation for targeted functional experiments aimed at understanding the activities of specific CYP450 and associated therapeutic potential during times of increased disease risk.

Hepatic IKKε expression is dispensable for high-fat feeding-induced increases in liver lipid content and alterations in glucose tolerance.

There are endocrine and immunological changes that occur during onset and progression of the overweight and obese states. The inhibitor of nuclear factor-κB kinase-ε (IKKε) was originally described as an inducible protein kinase; whole body gene deletion or systemic pharmaceutical targeting of this kinase improved insulin sensitivity and glucose tolerance in mice. To investigate the primary sites of action associated with IKKε during weight gain, we describe the first mouse line with conditional elimination of IKKε in the liver (IKKεAlb-/-). IKKεAlb-/- mice and littermate controls gain weight, show similar changes in body composition, and do not display any improvements in insulin sensitivity or whole body glucose tolerance. These studies were conducted using breeder chow diets and matched low- vs. high-fat diets. While glycogen accumulation in the liver is reduced in IKKεAlb-/- mice, lipid storage in liver is similar in IKKεAlb-/- mice and littermate controls. Our results using IKKεAlb-/- mice suggest that the primary action of this kinase to impact insulin sensitivity during weight gain lies predominantly within extrahepatic tissues.

L-carnitine supplementation attenuates NAFLD progression and cardiac dysfunction in a mouse model fed with methionine and choline-deficient diet

Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disorder. NAFLD, associated lipotoxicity, fibrosis, oxidative stress, and altered mitochondrial metabolism, is responsible for systemic inflammation, which contributes to organ dysfunction in extrahepatic tissues, including the heart.We investigated the ability of L-carnitine (LC) to oppose the pathogenic mechanisms underlying NAFLD progression and associated heart dysfunction, in a mouse model of methionine-choline-deficient diet (MCDD). Mice were divided into three groups: namely, the control group (CONTR) fed with a regular diet and two groups fed with MCDD for 6 weeks. In the last 3 weeks, one of the MCDD groups received LC (200 mg/kg each day) through drinking water (MCDD + LC).The hepatic lipid accumulation and oxidative stress decreased after LC supplementation, which also reduced hepatic fibrosis via modulation of α-smooth muscle actin (αSMA), peroxisome-activated receptor gamma (PPARγ), and nuclear factor kappa B (NfƙB) expression. LC ameliorated systemic inflammation, mitigated cardiac reactive oxygen species (ROS) production, and prevented fibrosis progression by acting on signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinase 1-2 (ERK1-2), and αSMA.This study confirms the existence of a relationship between fatty liver disease and cardiac abnormalities and highlights the role of LC in controlling liver oxidative stress, steatosis, fibrosis, and NAFLD-associated cardiac dysfunction.

Corticosteroid-Binding Globulin is expressed in the adrenal gland and its absence impairs corticosterone synthesis and secretion in a sex-dependent manner

Corticosteroid-binding globulin (CBG) is synthesized by the liver and secreted into the bloodstream where binds to glucocorticoids. Thus CBG has the role of glucocorticoid transport and free hormone control. In addition, CBG has been detected in some extrahepatic tissues without a known role. CBG-deficient mice show decreased total corticosterone levels with missing of classical sexual dimorphism, increased free corticosterone, higher adrenal gland size and altered HPA axis response to stress. Our aim was to ascertain whether CBG deficiency could affect the endocrine synthetic activity of adrenal gland and if the adrenal gland produces CBG. We determined the expression in adrenal gland of proteins involved in the cholesterol uptake and its transport to mitochondria and the main enzymes involved in the corticosterone, aldosterone and catecholamine synthesis. The results showed that CBG is synthesized in the adrenal gland. CBG-deficiency reduced the expression of ACTH receptor, SRB1 and the main genes involved in the adrenal hormones synthesis, stronger in females resulting in the loss of sexual dimorphism in corticosteroid adrenal synthesis, despite corticosterone content in adrenal glands from CBG-deficient females was similar to wildtype ones. In conclusion, these results point to an unexplored and relevant role of CBG in the adrenal gland functionality related to corticosterone production and release.

Extrahepatic complications of non-alcoholic fatty liver disease: Its impact beyond the liver.

Non-alcoholic fatty liver disease (NAFLD) is currently one of the main causes of chronic liver disease in Western countries, with a 25% prevalence reported in the general population worldwide. Visceral adiposity and liver fat promote a state of systemic inflammation, predisposing individuals with NAFLD to the extrahepatic pathologies of cardiovascular disease (the most common cause of death in patients with NAFLD), diabetes mellitus, chronic kidney disease, hypothyroidism, polycystic ovary syndrome, obstructive sleep apnea, and an increased risk for presenting with gastrointestinal and extraintestinal neoplasias. Different mechanisms between NAFLD and its association with extrahepatic diseases have been reported, and lipotoxicity is the main cause of inflammatory pathway activation that results in extrahepatic tissue damage.

Abundant Expression of Lysyl Oxidase-like 2 Protein in Intrahepatic Bile Ducts of Infants With Biliary Atresia.

Biliary atresia (BA) is characterized by rapidly progressive inflammation and fibrosis of the biliary tract, which usually progresses despite surgical intervention (Kasai hepatoportoenterostomy). Lysyl oxidase-like (LOXL2) is an extracellular matrix enzyme that catalyzes the cross-linking of fibrillar collagen and elastin and is thought to play a crucial role in tissue fibrosis; anti-LOXL2 drugs have been shown to be antifibrotic in animals. The aim of the study was to investigate the presence of LOXL2 in BA livers and hepatic and extrahepatic control tissues. Liver wedge biopsies from infants with BA (n = 20) were obtained at Kasai, and were compared with non-BA livers (n = 20). Liver fibrosis was scored using the Ishak scale, and immunohistochemistry was performed using a commercially available polyclonal anti-LOXL2 antibody. The expression of LOXL2 was scored for intensity and for distribution of bile duct staining by a pathologist blinded to the diagnosis. Staining of LOXL2 in pediatric control tissue, muscle (n = 5), heart (n = 5), and bone (n = 10) was performed. Tissue from patients with BA abundantly expressed LOXL2 (intensity score 2.0 vs 1.4 [P ≤ 0.001]) for non-BA and distribution of bile duct-staining score of 3.0 versus 2.8 (P = 0.001) for non-BA. Fibrosis score of all BA samples was 4.2 versus 3.1 for non-BA. Nonhepatic pediatric tissue displayed minimal to no LOXL2 staining. There is significant overexpression of LOXL2 in BA hepatic tissue with minimal expression in extrahepatic tissue. The over expression noted in human hepatic tissue at Kasai suggests the rationale for further investigation of anti-LOXL2 therapeutics in BA.