Sirolimus to treat chronic and steroid-resistant allograft rejection-related fibrosis in pediatric liver transplantation.

This study aimed to report our experience with the use of sirolimus in pediatric liver transplant patients with chronic rejection or steroid-resistant rejection with hepatic fibrosis, focusing on their histological evolution. All pediatric liver transplant recipients who received off-label treatment with sirolimus for chronic ductopenic rejection or cortico-resistant rejection between July 2003 and July 2022 were included in the study. All nine patients included in the study showed improvement in liver enzymes and cholestasis parameters as soon as 1-month after postsirolimus introduction. A decrease in fibrosis stage was observed in 7/9 (77.7%) patients at 36 months. All but one patient experienced an improvement in the Rejection Activity Index and ductopenia at 12 months. A single patient had to discontinue sirolimus treatment owing to nephrotic proteinuria. In conclusion, sirolimus may be a safe and effective treatment for chronic and steroid-resistant rejection and may improve allograft rejection-related fibrosis and ductal damage.

Gene therapy with AAV9-SGPL1 in an animal model of lung fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung that leads rapidly to respiratory failure. Novel approaches to treatment are urgently needed. The bioactive lipid sphingosine-1-phosphate (S1P) is increased in IPF lungs and promotes proinflammatory and profibrotic TGF-ß signaling. Hence, decreasing lung S1P represents a potential therapeutic strategy for IPF. S1P is degraded by the intracellular enzyme S1P lyase (SPL). Here we find that a knock-in mouse with a missense SPL mutation mimicking human disease resulted in reduced SPL activity, increased S1P, increased TGF-ß signaling, increased lung fibrosis, and higher mortality after injury compared to wild type (WT). We then tested adeno-associated virus 9 (AAV9)-mediated overexpression of human SGPL1 (AAV-SPL) in mice as a therapeutic modality. Intravenous treatment with AAV-SPL augmented lung SPL activity, attenuated S1P levels within the lungs, and decreased injury-induced fibrosis compared to controls treated with saline or only AAV. We confirmed that AAV-SPL treatment led to higher expression of SPL in the epithelial and fibroblast compartments during bleomycin-induced lung injury. Additionally, AAV-SPL decreased expression of the profibrotic cytokines TNFα and IL1ß as well as markers of fibroblast activation, such as fibronectin (Fn1), Tgfb1, Acta2, and collagen genes in the lung. Taken together, our results provide proof of concept for the use of AAV-SPL as a therapeutic strategy for the treatment of IPF. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Sialidase NEU3 action on GM1 ganglioside is neuroprotective in GM1 gangliosidosis.

GM1 gangliosidosis is a neurodegenerative disorder caused by mutations in the GLB1 gene, which encodes lysosomal ß-galactosidase. The enzyme deficiency blocks GM1 ganglioside catabolism, leading to accumulation of GM1 ganglioside and asialo-GM1 ganglioside (GA1 glycolipid) in brain. This disease can present in varying degrees of severity, with the level of residual ß-galactosidase activity primarily determining the clinical course. Glb1 null mouse models, which completely lack ß-galactosidase expression, exhibit a less severe form of the disease than expected from the comparable deficiency in humans, suggesting a potential species difference in the GM1 ganglioside degradation pathway. We hypothesized this difference may involve the sialidase NEU3, which acts on GM1 ganglioside to produce GA1 glycolipid. To test this hypothesis, we generated Glb1/Neu3 double KO (DKO) mice. These mice had a significantly shorter lifespan, increased neurodegeneration, and more severe ataxia than Glb1 KO mice. Glb1/Neu3 DKO mouse brains exhibited an increased GM1 ganglioside to GA1 glycolipid ratio compared with Glb1 KO mice, indicating that NEU3 mediated GM1 ganglioside to GA1 glycolipid conversion in Glb1 KO mice. The expression of genes associated with neuroinflammation and glial responses were enhanced in Glb1/Neu3 DKO mice compared with Glb1 KO mice. Mouse NEU3 more efficiently converted GM1 ganglioside to GA1 glycolipid than human NEU3 did. Our findings highlight NEU3's role in ameliorating the consequences of Glb1 deletion in mice, provide insights into NEU3's differential effects between mice and humans in GM1 gangliosidosis, and offer a potential therapeutic approach for reducing toxic GM1 ganglioside accumulation in GM1 gangliosidosis patients.

The significant IgG4 infiltrate in autoimmune hepatitis is associated with a greater ductular reaction and more advanced liver disease.

BACKGROUND: Sclerosing cholangitis is the typical IgG4-related disease digestive involvement. However, the role of the IgG4 liver expression in autoimmune hepatitis remains unknown. AIMS: to assess whether the expression of IgG4 plasma cells in patients with autoimmune hepatitis (AIH) was associated with different outcomes. METHODS: Retrospective study including patients diagnosed with AIH by biopsy from January-2009 to June-2021. At least mild IgG4 expression (>10 IgG4+-plasma cells per field) was considered as significant. RESULTS: 85 patients with AIH were included. Overall, 58.8% were women, mean age 54 years. Nine (10.6%) presented cirrhosis at diagnosis. Fifteen (17.6%) had significant IgG4 liver expression. Patients with IgG4 infiltrate were older (p = 0.021), presented liver cirrhosis more frequently (33.3% vs. 5.7%, p = 0.007), greater IgG plasma values (p = 0.008) and atypical ANCAs (p = 0.086); ductular reaction was also more common (p = 0.009). Complete remission rate was similar regardless of the IgG4 infiltrate. Time to corticosteroids discontinuation was longer in subjects with IgG4 infiltrate (p = 0.068), but second-line therapy tended to be less frequent (p = 0.187). CONCLUSION: Significant IgG4 liver infiltrate in patients with autoimmune hepatitis is associated with more advanced liver disease. The greater ductular reaction mediated by the IgG4 infiltrate may be the cause for this finding, though this finding should be prospectively assessed.

SARS-CoV-2 ORF3a expression in brain disrupts the autophagy-lysosomal pathway, impairs sphingolipid homeostasis, and drives neuropathogenesis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes injury to multiple organ systems, including the brain. SARS-CoV-2's neuropathological mechanisms may include systemic inflammation and hypoxia, as well as direct cell damage resulting from viral infections of neurons and glia. How the virus directly causes injury to brain cells, acutely and over the long term, is not well understood. In order to gain insight into this process, we studied the neuropathological effects of open reading frame 3a (ORF3a), a SARS-CoV-2 accessory protein that is a key pathological factor of the virus. Forced ORF3a brain expression in mice caused the rapid onset of neurological impairment, neurodegeneration, and neuroinflammation-key neuropathological features found in coronavirus disease (COVID-19, which is caused by SARS-CoV-2 infection). Furthermore, ORF3a expression blocked autophagy progression in the brain and caused the neuronal accumulation of α-synuclein and glycosphingolipids, all of which are linked to neurodegenerative disease. Studies with ORF3-expressing HeLa cells confirmed that ORF3a disrupted the autophagy-lysosomal pathway and blocked glycosphingolipid degradation, resulting in their accumulation. These findings indicate that, in the event of neuroinvasion by SARS-CoV-2, ORF3a expression in brain cells may drive neuropathogenesis and be an important mediator of both short- and long-term neurological manifestations of COVID-19.

Transforming growth factor-beta 1: A new factor reducing hepatic SHBG production in liver fibrosis.

Low plasma sex hormone-binding globulin (SHBG) levels are present in fatty liver disease, which represents a spectrum of diseases ranging from hepatocellular steatosis through steatohepatitis to fibrosis and irreversible cirrhosis. We have previously determined that fat accumulation reduces SHBG production in different nonalcoholic fatty liver disease mouse models. In the present work, we are interested in elucidating the molecular mechanisms reducing SHBG plasma levels in liver fibrosis. For this purpose, in vivo studies were performed using the human SHBG transgenic mice developing liver fibrosis induced by carbon tetrachloride (CCl4 ). Our results clearly showed that CCl4 induced liver fibrosis and reduced SHBG production by reducing hepatocyte nuclear factor 4 alpha (HNF-4α). The SHBG reduction could be influenced by the increase in transforming growth factor-beta 1 (TGF-ß1), which was increased in mice developing liver fibrosis. Therefore, we decided to evaluate the role of TGF-ß1 in regulating hepatic SHBG production. Results obtained in both HepG2 cells and human SHBG transgenic mice showed that TGF-ß1 reduced significantly SHBG messenger RNA and protein levels. Mechanistically TGF-ß1 downregulated P1-HNF-4α isoforms and increased P2-HNF-4α isoforms via Smad3 and Stat3 pathways through TGF-ß1 receptor I, resulting in transcriptional repression of the SHBG gene. Taken together, we found for the first time that TGF-ß1 is a new factor regulating hepatic SHBG production in liver fibrosis. Further research is needed to determine the role of this reduction in hepatic SHBG production in the progression of nonalcoholic steatohepatitis.

Non-Invasive Tests of Liver Fibrosis Help in Predicting the Development of Hepatocellular Carcinoma among Patients with NAFLD.

Background: The potential role of non-invasive tests (NITs) for liver fibrosis for hepatocellular carcinoma (HCC) prediction remains poorly known. Methods: Retrospective analysis of a NAFLD cohort from a single university hospital in Barcelona, Spain. Incidence rates and cumulative incidence for the overall cohort, as well as cirrhotic and non-cirrhotic patients were calculated. Logistic regression analyses were carried out to investigate risk factors of HCC. Results: From the entire cohort of 1040 patients, 996 patients (95.8%) were analyzed, in whom 35 cases of HCC were detected, of which 26 (72.4%) HCC incident cases were newly diagnosed during a median follow-up of 2.5 (1.9−3.6) years. Two-hundred and thirty-one (23.2%) were cirrhotic at baseline. With the exception of 2 (7.7%) cases of HCC, the rest were diagnosed in cirrhotic patients. Overall HCC cumulative incidence was 9.49 (95% CI 6.4−13.9) per 1000 person-years. The incidence rate for cirrhotic patients was 41.2 (95% CI 27.6−61.6) per 1000 person-years and 0.93 (95% CI 0.23−3.7) per 1000 person-years for patients without cirrhosis. Overall mortality was significantly higher amongst patients with HCC (4.4% vs. 30.8%, p < 0.001). In patients with available liver biopsy (n = 249, 25%), advanced fibrosis (F3−F4) was significantly associated with higher HCC incidence, but not steatosis, lobular inflammation, nor ballooning. In the overall cohort, FIB-4 ≥1.3 (HR 8.46, 95% CI 1.06−67.4, p = 0.044) and older age (HR 1.06, 95% CI 1.01−1.11, p = 0.025) were associated with increasing risk of HCC over time, whereas in cirrhotic patients predictors of HCC included decreasing values of albumin (HR 0.34, 95% CI 0.13−0.87, p = 0.024), platelets (HR 0.98, 95% CI 0.98−0.99, p = 0.001), and increasing values of liver stiffness (HR 1.03, 95% CI 1.00−1.06, p = 0.016). Conclusions: In a Spanish cohort of NAFLD patients, HCC was rare in non-cirrhotic patients. NITs might play a relevant role at predicting HCC.

Hepatic Rupture as the Initial Presentation of an EGFR-Mutated Lung Adenocarcinoma: A Case Report.

Hepatic rupture is a rare complication of solid tumor malignancies, notably in lung adenocarcinomas, and carries an extremely poor overall prognosis. Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma predict benefit with tyrosine kinase inhibitors (TKIs). This case report describes a female patient who presented with a metastatic hepatic rupture and was subsequently diagnosed with EGFR-mutated lung adenocarcinoma. The tumor had an impressive response to TKI inhibitor treatment, reversing her extremely poor, short-term prognosis. We believe this unique case sheds light on the treatment management of hepatic ruptures and supports the high response rate seen with TKIs in EGFR-mutated lung cancers, regardless of the patient's performance status.

Dental anthropological report: Exploring plant-based treatments through the analysis of dental calculus and sediment of dental caries in a woman from the Late Preceramic period, Peru.

Reconstructing plant-based healing treatments of past societies from a dental anthropological perspective is still challenging due to a wide range of plant species, many with both medicinal and nutritional properties, and limitations on plant-taxa identification. Starch grains and phytoliths retrieved in samples from dental calculus and sediment contained in the cavity of dental caries were examined to investigate the supply of a plant-based treatment in an individual buried in the Late Preceramic site of Huaca El Paraíso (2100-1500 BCE), whose osteological analysis reported the absence of any pathological condition at a bone tissue level. A variety of starch grains such as pumpkins, manioc, maize, and beans had an important role in the diet of the individual. The starch grains were embedded in their dental calculus, all of which, except for manioc, showed signs of cooking damage. Considering the context and characteristics of the crops, the nutritional properties of maize, pumpkins and beans are evident. However, parallel medicinal properties of manioc and maize could not be entirely denied. Phytoliths morphologically ascribed to the Asteraceae plant family, which suggest the consumption of medicinal plants of Andean vernacular use, were retrieved in the sediment of dental caries. Our results prove that the analysis of sediment obtained from dental caries is as valuable in tracing medicinal plant-based treatments as dental calculus in archaeological populations. There are still several limitations to approach this topic in dental anthropology, which are discussed in this report. The performance of both analyses -dental calculus and sediment of dental caries, is highly recommended.

Dysfunctional mitochondrial translation and combined oxidative phosphorylation deficiency in a mouse model of hepatoencephalopathy due to Gfm1 mutations.

Hepatoencephalopathy due to combined oxidative phosphorylation deficiency type 1 (COXPD1) is a recessive mitochondrial translation disorder caused by mutations in GFM1, a nuclear gene encoding mitochondrial elongation factor G1 (EFG1). Patients with COXPD1 typically present hepatoencephalopathy early after birth with rapid disease progression, and usually die within the first few weeks or years of life. We have generated two different mouse models: a Gfm1 knock-in (KI) harboring the p.R671C missense mutation, found in at least 10 patients who survived more than 1 year, and a Gfm1 knock-out (KO) model. Homozygous KO mice (Gfm1-/- ) were embryonically lethal, whereas homozygous KI (Gfm1R671C/R671C ) mice were viable and showed normal growth. R671C mutation in Gfm1 caused drastic reductions in the mitochondrial EFG1 protein content in different organs. Six- to eight-week-old Gfm1R671C/R671C mice showed partial reductions of in organello mitochondrial translation and respiratory complex IV enzyme activity in the liver. Compound heterozygous Gfm1R671C/- showed a more pronounced decrease of EFG1 protein in liver and brain mitochondria, as compared with Gfm1R671C/R671C mice. At 8 weeks of age, their mitochondrial translation rates were significantly reduced in both tissues. Additionally, Gfm1R671C/- mice showed combined oxidative phosphorylation deficiency (reduced complex I and IV enzyme activities in liver and brain), and blue native polyacrylamide gel electrophoresis analysis revealed lower amounts of both affected complexes. We conclude that the compound heterozygous Gfm1R671C/- mouse presents a clear dysfunctional molecular phenotype, showing impaired mitochondrial translation and combined respiratory chain dysfunction, making it a suitable animal model for the study of COXPD1.

Acquired hepatocerebral degeneration in a metastatic neuroendocrine tumor long-term survivor - an update on neuroendocrine neoplasm's treatment: A case report.

BACKGROUND: Metastatic small bowel low-grade neuroendocrine tumors (NETs) have a good prognosis. Surgery is the only curative treatment; however, this may induce advanced liver disease, particularly in long-term survivor patients. Acquired hepatocerebral degeneration or Parkinsonism in cirrhosis is characterized by rapidly progressive extrapyramidal symptoms in patients with advanced liver disease. CASE SUMMARY: A 70-year-old man presented to the emergency department with diminished consciousness and disorientation, and was diagnosed with hepatic encephalopathy. The patient was diagnosed in 1993 with a metastatic small bowel NET, for which he twice underwent hepatic surgery, with metastatic resection in 1993 and a right hepatectomy in 2002 to remove two hepatic metastases. In 2003, the patient started first-line chemotherapy and in 2004 started the first of three consecutive biological treatments, followed by radio-molecular therapy, achieving stable disease for 14 years. Disease progression was identified and he underwent an endoscopic retrograde cholangiopancreatography. However, in 2019 advanced liver disease was identified. We diagnosed the development of acquired hepatocerebral degeneration, an unusual long-term side effect after multiple hepatic procedures. CONCLUSION: The importance of regular and ongoing surveillance in long-term NET survivors who undergo hepatic procedures should be integrated into the therapeutic management plan, as some of these negative outcomes could be prevented.

Características clínicas de anorexia nervosa extrema. Reporte de caso / Clinical Characteristics of Extreme Anorexia Nervosa. A Case Report

Resumen La Anorexia Nervosa es considerada en la actualidad como enfermedad de gran impacto por su asociación con la desnutrición, se presenta principalmente en mujeres adolescentes y adultas jóvenes. La gravedad se establece a través del índice de masa corporal (IMC). Es una enfermedad multifactorial, con gran influencia del medio cultural, los aspectos biológicos, familiares y personales. Ningún sistema corporal se salva de las secuelas adversas de estas enfermedades, especialmente a medida que la anorexia nervosa se vuelve más grave y crónica. Se realiza una revisión de las complicaciones médicas asociadas con la anorexia nervosa extrema en este caso clínico. Se considera además como una enfermedad con alto índice de morbimortalidad, por el incremento de hasta 6 veces el riesgo de muerte y las múltiples complicaciones médicas que se asocian a la enfermedad. De ahí que es imprescindible incrementar los recursos de salud, reforzar la información en los médicos de primer contacto para identificar este padecimiento, y aumentar los factores de buen pronóstico como la atención temprana de los pacientes.

Abstract Anorexia nervosa is currently considered a disease of great impact due to its association with malnutrition. It occurs mainly in women, adolescents and young adults. The severity is de- fined by BMI. It is a multifactorial disease, with great influence of the cultural environment, biological, family and personal aspects. No system in the body is spared from the adverse sequelae of these illnesses, especially as anorexia nervosa becomes more severe and chronic. We review the medical complications that are associated with extreme anorexia nervosa. It is also considered as a disease with a high morbidity and mortality rate, due to an increase of up to 6 times the risk of death and the multiple medical complications associated with the disease. Hence, it is essential to increase health resources, reinforce information in first-contact doctors to identify this condition, and increase factors of good prognosis such as early patient care.

Genetic defects in the sphingolipid degradation pathway and their effects on microglia in neurodegenerative disease.

Sphingolipids, which function as plasma membrane lipids and signaling molecules, are highly enriched in neuronal and myelin membranes in the nervous system. They are degraded in lysosomes by a defined sequence of enzymatic steps. In the related group of disorders, the sphingolipidoses, mutations in the genes that encode the individual degradative enzymes cause lysosomal accumulation of sphingolipids and often result in severe neurodegenerative disease. Here we review the information indicating that microglia, which actively clear sphingolipid-rich membranes in the brain during development and homeostasis, are directly affected by these mutations and promote neurodegeneration in the sphingolipidoses. We also identify parallels between the sphingolipidoses and more common forms of neurodegeneration, which both exhibit evidence of defective sphingolipid clearance in the nervous system.

Parvovirus B19 Myocarditis: Looking Beyond the Heart.

Human parvovirus B19 represents the most common etiology of myocarditis in the pediatric population. Although it usually causes a benign exanthematic viral infection, parvovirus B19 may also present as disseminated disease with tropism for the myocardium, causing heart failure with high mortality. We present the case of a 2-year-old patient with fulminating acute myocarditis in whom the histological, immunophenotypic, and microbiological findings in necropsy showed multiorgan involvement caused by parvovirus B19. The autopsy revealed changes due to infection with parvovirus B19 as well as hypoxic-ischemic and secondary autoimmune changes. Medullary aplasia was observed, transmural lymphocyte myocarditis, lymphocytosis in the dermis with endothelial cells positive for parvovirus B19 in immunohistochemistry, cholestatic hepatitis due to ischemia and autoimmune hepatitis, lymphadenitis, and signs of hemophagocytosis. We also found hypoxic-ischemic encephalopathy.

Transient elastography in DAA era. Relation between post-SVR LSM and histology.

The natural history of HCV chronic infection has drastically changed after direct-acting antiviral treatment. Due to the high sustained virological response (SVR) achieved, noninvasive estimation of liver fibrosis regression has become a major key point. The present study tries to evaluate the relation between liver histology and liver stiffness measurement (LSM) by transient elastography (TE) after SVR.

The Ormdl genes regulate the sphingolipid synthesis pathway to ensure proper myelination and neurologic function in mice.

Sphingolipids are membrane and bioactive lipids that are required for many aspects of normal mammalian development and physiology. However, the importance of the regulatory mechanisms that control sphingolipid levels in these processes is not well understood. The mammalian ORMDL proteins (ORMDL1, 2 and 3) mediate feedback inhibition of the de novo synthesis pathway of sphingolipids by inhibiting serine palmitoyl transferase in response to elevated ceramide levels. To understand the function of ORMDL proteins in vivo, we studied mouse knockouts (KOs) of the Ormdl genes. We found that Ormdl1 and Ormdl3 function redundantly to suppress the levels of bioactive sphingolipid metabolites during myelination of the sciatic nerve. Without proper ORMDL-mediated regulation of sphingolipid synthesis, severe dysmyelination results. Our data indicate that the Ormdls function to restrain sphingolipid metabolism in order to limit levels of dangerous metabolic intermediates that can interfere with essential physiological processes such as myelination.

Human GLB1 knockout cerebral organoids: A model system for testing AAV9-mediated GLB1 gene therapy for reducing GM1 ganglioside storage in GM1 gangliosidosis.

GM1 gangliosidosis is an autosomal recessive neurodegenerative disorder caused by the deficiency of lysosomal ß-galactosidase (ß-gal) and resulting in accumulation of GM1 ganglioside. The disease spectrum ranges from infantile to late onset and is uniformly fatal, with no effective therapy currently available. Although animal models have been useful for understanding disease pathogenesis and exploring therapeutic targets, no relevant human central nervous system (CNS) model system has been available to study its early pathogenic events or test therapies. To develop a model of human GM1 gangliosidosis in the CNS, we employed CRISPR/Cas9 genome editing to target GLB1 exons 2 and 6, common sites for mutations in patients, to create isogenic induced pluripotent stem (iPS) cell lines with lysosomal ß-gal deficiency. We screened for clones with <5% of parental cell line ß-gal enzyme activity and confirmed GLB1 knockout clones using DNA sequencing. We then generated GLB1 knockout cerebral organoids from one of these GLB1 knockout iPS cell clones. Analysis of GLB1 knockout organoids in culture revealed progressive accumulation of GM1 ganglioside. GLB1 knockout organoids microinjected with AAV9-GLB1 vector showed a significant increase in ß-gal activity and a significant reduction in GM1 ganglioside content compared with AAV9-GFP-injected organoids, demonstrating the efficacy of an AAV9 gene therapy-based approach in GM1 gangliosidosis. This proof-of-concept in a human cerebral organoid model completes the pre-clinical studies to advance to clinical trials using the AAV9-GLB1 vector.

Murine platelet production is suppressed by S1P release in the hematopoietic niche, not facilitated by blood S1P sensing.

The bioactive lipid mediator sphingosine 1-phosphate (S1P) was recently assigned critical roles in platelet biology: whereas S1P1 receptor-mediated S1P gradient sensing was reported to be essential for directing proplatelet extensions from megakaryocytes (MKs) toward bone marrow sinusoids, MK sphingosine kinase 2 (Sphk2)-derived S1P was reported to further promote platelet shedding through receptor-independent intracellular actions, and platelet aggregation through S1P1 Yet clinical use of S1P pathway modulators including fingolimod has not been associated with risk of bleeding or thrombosis. We therefore revisited the role of S1P in platelet biology in mice. Surprisingly, no reduction in platelet counts was observed when the vascular S1P gradient was ablated by impairing S1P provision to plasma or S1P degradation in interstitial fluids, nor when gradient sensing was impaired by S1pr1 deletion selectively in MKs. Moreover, S1P1 expression and signaling were both undetectable in mature MKs in situ, and MK S1pr1 deletion did not affect platelet aggregation or spreading. When S1pr1 deletion was induced in hematopoietic progenitor cells, platelet counts were instead significantly elevated. Isolated global Sphk2 deficiency was associated with thrombocytopenia, but this was not replicated by MK-restricted Sphk2 deletion and was reversed by compound deletion of either Sphk1 or S1pr2, suggesting that this phenotype arises from increased S1P export and S1P2 activation secondary to redistribution of sphingosine to Sphk1. Consistent with clinical observations, we thus observe no essential role for S1P1 in facilitating platelet production or activation. Instead, S1P restricts megakaryopoiesis through S1P1, and can further suppress thrombopoiesis through S1P2 when aberrantly secreted in the hematopoietic niche.

Sex Hormone-Binding Globulin Expression Correlates With Acetyl-Coenzyme A Carboxylase and Triglyceride Content in Human Liver.

CONTEXT: There is emerging evidence that SHBG is substantially reduced in chronic metabolic diseases, including obesity and nonalcoholic fatty liver disease (NAFLD). We have recently reported, through use of in vitro (HepG2 cells) and in vivo (SHBG-C57BL/ksJ-db/db mice) models, that SHBG could play a role in arresting the progression of NAFLD by downregulating lipogenesis. OBJECTIVE: The main aim of this study was to investigate the mechanisms by which SHBG prevents hepatic lipogenesis by examining the relationship between SHBG and a key lipogenic enzyme, such as acetyl-coenzyme A carboxylase (ACC) in the liver of obese persons. PARTICIPANTS AND METHODS: SHBG and ACC mRNA levels, as well as triglyceride content, were analyzed in 41 liver samples from nondiabetic obese patients with NAFLD who had undergone bariatric surgery. We also studied the effect of SHBG overexpression in HepG2 cells cultured under high-glucose conditions. RESULTS: SHBG mRNA and protein levels were lower in patients with metabolic syndrome than in those without metabolic syndrome; however, these differences were significant only for mRNA level. SHBG mRNA levels correlated positively with SHBG protein levels and hepatic triglyceride content. In addition, SHBG mRNA and protein levels correlated negatively with ACC mRNA levels and triglyceride content. Furthermore, SHBG overexpression abrogated the increase in ACC expression induced by high-glucose treatment in HepG2 cells. CONCLUSIONS: Our findings suggest that SHBG plays a role in regulating hepatic lipogenesis by reducing ACC levels. These results suggest a strategy for the treatment of NAFLD.