Cerium oxide nanoparticles improve liver regeneration after acetaminophen-induced liver injury and partial hepatectomy in rats

Background and aims: Cerium oxide nanoparticles are effective scavengers of reactive oxygen species and have been proposed as a treatment for oxidative stress-related diseases. Consequently, we aimed to investigate the effect of these nanoparticles on hepatic regeneration after liver injury by partial hepatectomy and acetaminophen overdose. Methods: All the in vitro experiments were performed in HepG2 cells. For the acetaminophen and partial hepatectomy experimental models, male Wistar rats were divided into three groups: (1) nanoparticles group, which received 0.1 mg/kg cerium nanoparticles i.v. twice a week for 2 weeks before 1 g/kg acetaminophen treatment, (2) N-acetyl-cysteine group, which received 300 mg/kg of N-acetyl-cysteine i.p. 1 h after APAP treatment and (3) partial hepatectomy group, which received the same nanoparticles treatment before partial hepatectomy. Each group was matched with vehicle-controlled rats. Results: In the partial hepatectomy model, rats treated with cerium oxide nanoparticles showed a significant increase in liver regeneration, compared with control rats. In the acetaminophen experimental model, nanoparticles and N-acetyl-cysteine treatments decreased early liver damage in hepatic tissue. However, only the effect of cerium oxide nanoparticles was associated with a significant increment in hepatocellular proliferation. This treatment also reduced stress markers and increased cell cycle progression in hepatocytes and the activation of the transcription factor NF-κB in vitro and in vivo. Conclusions: Our results demonstrate that the nanomaterial cerium oxide, besides their known antioxidant capacities, can enhance hepatocellular proliferation in experimental models of liver regeneration and drug-induced hepatotoxicity

Lethal congenital contracture syndrome 11: A case report and literature review

Lethal congenital contracture syndrome 11 (LCCS11) is caused by homozygous or compound heterozygous variants in the GLDN gene on chromosome 15q21. GLDN encodes gliomedin, a protein required for the formation of the nodes of Ranvier and development of the human peripheral nervous system. We report a fetus with ultrasound alterations detected at 28 weeks of gestation. The fetus exhibited hydrops, short long bones, fixed limb joints, absent fetal movements, and polyhydramnios. The pregnancy was terminated and postmortem studies confirmed the prenatal findings: distal arthrogryposis, fetal growth restriction, pulmonary hypoplasia, and retrognathia. The fetus had a normal chromosomal microarray analysis. Exome sequencing revealed two novel compound heterozygous variants in the GLDN associated with LCCS11. This manuscript reports this case and performs a literature review of all published LCCS11 cases

Monogenic conditions and central nervous system anomalies:A prospective study, systematic review and meta-analysis

Objectives: Determine the incremental diagnostic yield of prenatal exome sequencing (pES) over chromosome microarray (CMA) or G-banding karyotype in fetuses with central nervous system (CNS) abnormalities.Methods: Data were collected via electronic searches from January 2010 to April 2022 in MEDLINE, Cochrane, Web of Science and EMBASE. The NHS England prenatal exome cohort was also included. Incremental yield was calculated as a pooled value using a random-effects model. Results: Thirty studies were included (n = 1583 cases). The incremental yield with pES for any CNS anomaly was 32% [95%CI 27%–36%; I2 = 72%]. Subgroup analysis revealed apparent incremental yields in; (a) isolated CNS anomalies; 27% [95%CI 19%–34%; I2 = 74%]; (b) single CNS anomaly; 16% [95% CI 10%–23%; I2 = 41%]; (c) more than one CNS anomaly; 31% [95% Cl 21%–40%; I2 = 56%]; and (d) the anatomical subtype with the most optimal yield was Type 1 malformation of cortical development, related to abnormal cell proliferation or apoptosis, incorporating microcephalies, megalencephalies and dysplasia; 40% (22%–57%; I2 = 68%). The commonest syndromes in isolated cases were Lissencephaly 3 and X-linked hydrocephalus. Conclusions: Prenatal exome sequencing provides a high incremental diagnostic yield in fetuses with CNS abnormalities with optimal yields in cases with multiple CNS anomalies, particularly those affecting the midline, posterior fossa and cortex.</p

Nuevos mecanismos de regulación hepática mediados por miR-33 y el receptor de las lipoproteinas de baja densidad

[spa] El hígado es un órgano que presenta una gran capacidad regenerativa. Para estudiar este fenómeno, el modelo de hepatectomía parcial en ratón es el más adecuado (Higgins GM, Anderson RM. Arch Pathol. 1931). Esta técnica, conjuntamente con el uso de modelos animales modificados genéticamente, nos puede facilitar el estudio de las diferentes moléculas o vías de señalización implicadas en el proceso de regeneración hepática. La resección hepática es una de las medidas terapéuticas más efectivas para el tratamiento del carcinoma hepatocelular. Uno de los problemas a los que se enfrentan estos pacientes es que la aparición de un hepatocarcinoma se asienta sobre un hígado fibrótico o cirrótico. En este contexto clínico, la técnica de la resección se ve comprometida debido a que el hígado cirrótico regenera deficientemente (Bège T, et al. J Gastrointest Surg. 2007). Por este motivo, el procedimiento quirúrgico está asociado a un índice muy elevado de mortalidad (entre el 20 y el 50% según diversos autores). Es por ello, que hipotetizamos que el estudio de la regeneración hepática y el hallazgo de nuevas vías de señalización implicadas en este proceso, posibilitarán el desarrollo de nuevas dianas terapéuticas para el tratamiento de la enfermedad hepática crónica. En este contexto, creemos que el estudio de las vías de regulación del metabolismo lipídico hepático tienen más potencialidad terapéutica. Por ejemplo, se ha demostrado que el colesterol es importante en la proliferación celular y se conoce que su deficiencia evita la progresión de las células a través del ciclo celular. Se sabe que cuando hay una acumulación de esteroles, disminuyen la actividad de la proteína HMGCR (HMG-coA reductasa) una enzima limitante en la síntesis del colesterol) y la expresión del receptor de las lipoproteínas de baja densidad (LDL). Por el contrario, cuando disminuyen los niveles de colesterol las células mantienen la actividad de la proteína HMGCR y aumenta la expresión del receptor LDL (LDLR). Todo este proceso está regulado por el factor de transcripción SREBP (Brown MS et al. Cell, 1997 y Espenshade PJ. J Cell Sci. 2006). A parte de la implicación del colesterol en la regulación del ciclo celular, también es conocido que durante la regeneración hepática se acumulan grandes cantidades de lípidos en forma de gotas llamadas lipid droplets, las cuales están compuestas mayoritariamente por colesterol y ésteres de colesterol. (Garcia-Arcos I. et al. Lipids. 2010). Aun no se conocen con exactitud los mecanismos y la funcionalidad de esta esteatosis transitoria, ni los mecanismos a través de los cuales la célula es capaz de acumular lípidos durante el proceso regenerativo. Lo que si se ha observado es que tras la hepatectomía parcial existe un descenso de lípidos en el suero, y un aumento de la expresión del gen LDLR. Estos datos sugieren que este receptor estaría involucrado en el transporte de los lípidos hasta el interior de la célula. (Bocchetta M. et al. J Cell Physiol. 1993). Teniendo en cuenta los antecedentes descritos, el objetivo general de la presente tesis doctoral fue el de investigar como afecta el metabolismo lipídico al ciclo celular y a la regeneración hepática. Específicamente, la tesis se ha dividido en dos estudios: PRIMER ESTUDIO: - El miR-33 se encuentra en el mismo locus genómico que el gen Srebp, y se ha demostrado que este gen regula el ciclo celular. Por lo tanto el objetivo general del primer estudio fue: - Estudiar el papel del miR-33 en la regulación del ciclo celular y su implicación en la regeneración hepática. Objetivos específicos: 1. Estudiar la función de miR-33 en la regulación de las CDKs y las ciclinas y, por tanto, su papel en la regulación del ciclo celular. 2. Identificar posibles dianas de interacción de miR-33 con el 3’UTR de las quinasas dependientes de ciclina (CDKs). 3. Caracterizar la función del miR-33 durante la regeneración hepática en ratones a los que se les ha practicado una hepatectomía parcial. SEGUNDO ESTUDIO: La hipótesis específica del segundo estudio plantea que la actividad del receptor de las LDL afecta al lipidoma del hepatocito durante el proceso de regeneración hepática. Por lo tanto el objetivo general del estudio fue: • Analizar el efecto de la deficiencia del receptor LDL en la formación de lipid droplets y en la proliferación hepatocelular durante la regeneración hepática inducida por hepatectomía parcial. Los resultados obtenidos en el primer estudio se resumen en: 1. El miR33 regula la expresión post-transcripcional de la ciclina dependiente de quinasa CDK6 y de la ciclina D1. 2. miR33 se une de manera directa al 3’UTR de los mRNA de Cdk6 y Ccnd1. 3. El miR33 regula la proliferación celular y la progresión del ciclo celular. 4. El antagonismo de miR33 en ratones promueve la regeneración hepática. Los resultados obtenidos en el primer estudio se resumen en: 1. Los ratones LDLR-/- presentan esteatosis y niveles elevados de colesterol circulante. 2. Los ratones LDLR-/- presentan una peor regeneración hepática y presentan una disminución de la función hepática tras la PHx. 3. Los LDLR-/- presentan una alteración en la progresión del ciclo celular y una menor expresión de IL-6, TNF-α y HGF durante la regeneración hepática. 4. La deficiencia del gen LDLR no interfiere en la formación de los lipids droplets pero si en la composición de los mismos. Considerando los resultados presentados en esta Tesis Doctoral formulamos las siguientes conclusiones: 1. miR-33 regula la expresión de los genes Cdk6 y Ccnd1. 2. La regulación de los genes Cdk6 y Ccnd1 se lleva a cabo mediante la unión específica de miR-33 al los transcritos de estos genes. 3. miR-33 regula la proliferación celular de hepatocitos mediante la inhibición de la expresión de Cdk6 y Ccnd1. 4. El tratamiento de ratones hepatectomizados con anti-miR-33 estimula la regeneración hepática. 5. Los ratones deficientes en LDLR presentan una regeneración hepática anómala tras el procedimiento quirúrgico de la hepatectomia parcial. 6. Los ratones deficientes en LDLR muestran una disminución significativa de la función hepática en las etapas iniciales del proceso de regeneración tras una PHx. 7. Los ratones deficientes en LDLR presentan una desregulación de los niveles de IL-6, TNF-alfa y HGF hepáticos durante la regeneración hepática. 8. Los ratones deficientes en LDLR muestran una disminución de la expresión hepática de marcadores de ciclo celular. 9. La deficiencia del gen LDL modifica el lipidoma hepático pero no compromete la formación de lipid droplets. 10. El hígado en regeneración de los ratones deficientes en LDLR-/- presenta una concentración de ésteres de colesterol, colesterol y fosfatidilcolina compatible con un estado quiescente; en contraposición a la composición del lipidoma que predomina en los hígados regenerativos. Considerando las conclusiones expuestas, nuestros datos sugieren que miR-33 tiene potencialidad terapéutica como modulador de la regeneración hepática en el contexto clínico. Además, creemos que el estudio del lipidoma hepático, previo o inmediatamente posterior a la resección hepática, permitiría prever posibles complicaciones hepáticas en pacientes a los que se les ha practicado una hepatectomía terapéutica.[eng] Liver shows a well-known regenerative capacity. To study this phenomenon, the partial hepatectomy in rodents has been shown to be the most suitable model. This technique, in combination with the use of genetically modified animal models, can accelerate the study of different molecules or signaling pathways involved in the regeneration process. One of the signaling pathways that potentially have a therapeutically impact are the regulatory pathways of hepatic lipid metabolism. It has been demonstrated that cholesterol is important in cell proliferation and it is known that deficiency prevents the progression of cells through the cell cycle. This process is regulated by the transcription factor SREBP. It is also known that during liver regeneration, there is an accumulation of large amounts of lipids in the form of drops called lipid droplets, which are composed largely of cholesterol and cholesterol esters. It has been observed that after a partial hepatectomy there is a reduction of lipid levels in plasma, and increases the expression of the LDLR gene, suggesting that this receptor might be involved in the transport of lipids through the cell. The overall objective of this thesis was to assess how the lipid metabolism affects the cell cycle during liver regeneration at two different levels. - To study the role of miR-33, a micro RNA encoded in an intronic region of the SREBP gene, in cell cycle regulation and its implication in liver regeneration. -Using genetically modified LDLR-/- mice, analyze the effect of the deficiency of the LDL receptor in the formation of lipid droplets and hepatocellular proliferation during liver regeneration induced by partial hepatectomy. As the results, this thesis proves that miR-33 regulates the post-transcriptional expression of CDK6 and C1 by binding specifically at the 3`UTR of both mRNAs. Therefore miR-33 itself regulates the cell proliferation and cell cycle. A synthetic antagonist of miR-33 stimulates liver regeneration in healthy mice. On the other hand LDLR-/- mice show a deficient liver regeneration and a deficient hepatic function after a partial hepatectomy. Biochemistry and molecular analyses indicate that these mice show altered cell cycle and a decreased expression of different growth factors (IL-6, TNF-alpha and HGF) in the event of hepatic damage. Although LDLR-/- mice are able to form lipid droplets, there are significatively changes on its composition and might be used as an indication of the liver regeneration potential or its performance Our data suggests that miR-33 is an hepatic regeneration modulator and can become a future target molecule in the clinical context because its therapeutical potential. Furthermore the study of hepatic lipidome on patients that need to undergo hepatic surgery might be a tool to foresee failure and decreases the mortality and morbidity of hepatectomy as a therapeutic tool

The Contribution of QF-PCR and pathology studies in the diagnosis of diandric triploidy/partial mole

Objective: the aim of our study was to assess the contribution of quantitative fluorescent polymerase chain reaction (QF-PCR) and pathology studies in the diagnosis of diandric triploidies/partial hydatidiform moles. Methods: this study included all fet al triploidies diagnosed by QF-PCR in chorionic villi or amniotic fluid in the 2 centers of BCNatal in which a maternal saliva sample was used to establish its parental origin. Pathology studies were performed in products of conception and concordance between a partial hydatidiform mole diagnosis and the finding of a diandric triploidy was assessed. Results: among 46 fetal triploidies, found in 13 ongoing pregnancies and in 33 miscarriages, there were 26 (56%) diandric triploidies. Concordant molecular (diandric triploidy) and pathology results (partial mole) were achieved in 14 cases (54%), while in 6 cases (23%) pathology studies were normal, and in the remaining 6 cases (23%) pathology studies could not be performed because miscarriage was managed medically. Conclusions: diandric triploidy is associated with partial hydatidiform mole and its diagnosis is crucial to prevent the development of persistent trophoblastic disease. QF-PCR analysis in chorionic villi or amniotic fluid provides a more accurate diagnosis of the parental origin of triploidy than the classical pathology studie

La sobreexpresión de FoxO1 en el hígado esta positivamente asociada al grado de daño hepático en pacientes cirróticos

La enfermedad hepática crónica y sus complicaciones, la cirrosis y el carcinoma hepatocelular, presentan una elevada mortalidad. Los tratamientos curativos, como la hepatectomía parcial o el trasplante hepático, tienen una aplicación limitada en pacientes con cirrosis, por su escasa capacidad de regeneración hepática. Son necesarias otras alternativas diagnósticas y terapéuticas para prevenir la progresión de la enfermedad y mejorar la supervivencia. Diversos estudios preclínicos demuestran el importante papel de la proteína quinasa B(Akt) en la disfunción hepática, aunque aún se desconoce el estado de Akt y sus dianas en las patologías hepáticas crónicas. El principal objetivo es determinar el estado de activación de la vía Akt y su relación con la función hepática en pacientes cirróticos

Akt-mediated FoxO1 inhibition is required for liver regeneration

Understanding the hepatic regenerative process has clinical interest as the effectiveness of many treatments for chronic liver diseases is conditioned by efficient liver regeneration. Experimental evidence points to the need for a temporal coordination between cytokines, growth factors, and metabolic signaling pathways to enable successful liver regeneration. One intracellular mediator that acts as a signal integration node for these processes is the serine-threonine kinase Akt/protein kinase B (Akt). To investigate the contribution of Akt during hepatic regeneration, we performed partial hepatectomy in mice lacking Akt1, Akt2, or both isoforms. We found that absence of Akt1 or Akt2 does not influence liver regeneration after partial hepatectomy. However, hepatic-specific Akt1 and Akt2 null mice show impaired liver regeneration and increased mortality. The major abnormal cellular events observed in total Akt-deficient livers were a marked reduction in cell proliferation, cell hypertrophy, glycogenesis, and lipid droplet formation. Most importantly, liver-specific deletion of FoxO1, a transcription factor regulated by Akt, rescued the hepatic regenerative capability in Akt1-deficient and Akt2- deficient mice and normalized the cellular events associated with liver regeneration. Conclusion: The Akt-FoxO1 signaling pathway plays an essential role during liver regeneration

Liver FoxO1 overexpression is positively associated with the degree of liver injury in cirrhotic patients

Chronic liver disease and related complications, cirrhosis and hepatocellular carcinoma, are associated with high mortality. Curative treatments, partial hepatectomy or liver transplantation, have limited applicability in patients with cirrhosis due to the poor liver regenerative capacity. Thus, we need to find new diagnostic and therapeutic alternatives, to block the disease progression and to improve the survival of patients. In this context, preclinical studies have demonstrated the key role of the protein kinase B (Akt) in liver dysfunction, but the status of Akt and its targets in patients with chronic hepatopathy remains unknown. Aims: To determine the activation status of the Akt pathway and their association with liver functionality in cirrhotic patients

Cerium oxide nanoparticles improve liver regeneration after acetaminophen-induced liver injury and partial hepatectomy in rats

Background and aims: Cerium oxide nanoparticles are effective scavengers of reactive oxygen species and have been proposed as a treatment for oxidative stress-related diseases. Consequently, we aimed to investigate the effect of these nanoparticles on hepatic regeneration after liver injury by partial hepatectomy and acetaminophen overdose. Methods: All the in vitro experiments were performed in HepG2 cells. For the acetaminophen and partial hepatectomy experimental models, male Wistar rats were divided into three groups: (1) nanoparticles group, which received 0.1 mg/kg cerium nanoparticles i.v. twice a week for 2 weeks before 1 g/kg acetaminophen treatment, (2) N-acetyl-cysteine group, which received 300 mg/kg of N-acetyl-cysteine i.p. 1 h after APAP treatment and (3) partial hepatectomy group, which received the same nanoparticles treatment before partial hepatectomy. Each group was matched with vehicle-controlled rats. Results: In the partial hepatectomy model, rats treated with cerium oxide nanoparticles showed a significant increase in liver regeneration, compared with control rats. In the acetaminophen experimental model, nanoparticles and N-acetyl-cysteine treatments decreased early liver damage in hepatic tissue. However, only the effect of cerium oxide nanoparticles was associated with a significant increment in hepatocellular proliferation. This treatment also reduced stress markers and increased cell cycle progression in hepatocytes and the activation of the transcription factor NF-κB in vitro and in vivo. Conclusions: Our results demonstrate that the nanomaterial cerium oxide, besides their known antioxidant capacities, can enhance hepatocellular proliferation in experimental models of liver regeneration and drug-induced hepatotoxicity