Extracellular Vesicles as Delivery Vehicles for Non-Coding RNAs: Potential Biomarkers for Chronic Liver Diseases.

In recent years, EVs have emerged as promising vehicles for coding and non-coding RNAs (ncRNAs), which have demonstrated remarkable potential as biomarkers for various diseases, including chronic liver diseases (CLDs). EVs are small, membrane-bound particles released by cells, carrying an arsenal of ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and other ncRNA species, such as piRNAs, circRNAs, and tsRNAs. These ncRNAs act as key regulators of gene expression, splicing, and translation, providing a comprehensive molecular snapshot of the cells of origin. The non-invasive nature of EV sampling, typically via blood or serum collection, makes them highly attractive candidates for clinical biomarker applications. Moreover, EV-encapsulated ncRNAs offer unique advantages over traditional cell-free ncRNAs due to their enhanced stability within the EVs, hence allowing for their detection in circulation for extended periods and enabling more sensitive and reliable biomarker measurements. Numerous studies have investigated the potential of EV-enclosed ncRNAs as biomarkers for CLD. MiRNAs, in particular, have gained significant attention due to their ability to rapidly respond to changes in cellular stress and inflammation, hallmarks of CLD pathogenesis. Elevated levels of specific miRNAs have been consistently associated with various CLD subtypes, including metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction-associated steatohepatitis (MASH), and chronic hepatitis B and C. LncRNAs have also emerged as promising biomarkers for CLD. These transcripts are involved in a wide range of cellular processes, including liver regeneration, fibrosis, and cancer progression. Studies have shown that lncRNA expression profiles can distinguish between different CLD subtypes, providing valuable insights into disease progression and therapeutic response. Promising EV-enclosed ncRNA biomarkers for CLD included miR-122 (elevated levels of miR-122 are associated with MASLD progression and liver fibrosis), miR-21 (increased expression of miR-21 is linked to liver inflammation and fibrosis in CLD patients), miR-192 (elevated levels of miR-192 are associated with more advanced stages of CLD, including cirrhosis and HCC), LncRNA HOTAIR (increased HOTAIR expression is associated with MASLD progression and MASH development), and LncRNA H19 (dysregulation of H19 expression is linked to liver fibrosis and HCC progression). In the present review, we focus on the EV-enclosed ncRNAs as promising tools for the diagnosis and monitoring of CLD of various etiologies.

FLVCR1a Controls Cellular Cholesterol Levels through the Regulation of Heme Biosynthesis and Tricarboxylic Acid Cycle Flux in Endothelial Cells.

Feline leukemia virus C receptor 1a (FLVCR1a), initially identified as a retroviral receptor and localized on the plasma membrane, has emerged as a crucial regulator of heme homeostasis. Functioning as a positive regulator of δ-aminolevulinic acid synthase 1 (ALAS1), the rate-limiting enzyme in the heme biosynthetic pathway, FLVCR1a influences TCA cycle cataplerosis, thus impacting TCA flux and interconnected metabolic pathways. This study reveals an unexplored link between FLVCR1a, heme synthesis, and cholesterol production in endothelial cells. Using cellular models with manipulated FLVCR1a expression and inducible endothelial-specific Flvcr1a-null mice, we demonstrate that FLVCR1a-mediated control of heme synthesis regulates citrate availability for cholesterol synthesis, thereby influencing cellular cholesterol levels. Moreover, alterations in FLVCR1a expression affect membrane cholesterol content and fluidity, supporting a role for FLVCR1a in the intricate regulation of processes crucial for vascular development and endothelial function. Our results underscore FLVCR1a as a positive regulator of heme synthesis, emphasizing its integration with metabolic pathways involved in cellular energy metabolism. Furthermore, this study suggests that the dysregulation of heme metabolism may have implications for modulating lipid metabolism. We discuss these findings in the context of FLVCR1a's potential heme-independent function as a choline importer, introducing additional complexity to the interplay between heme and lipid metabolism.

Chronic Liver Diseases: What is Up?

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Smart nano-sized extracellular vesicles for cancer therapy: Potential theranostic applications in gastrointestinal tumors.

Extracellular vesicles (EVs) have gained tremendous interest in the search for next-generation therapeutics for the treatment of a range of pathologies, including cancer, especially due to their small size, biomolecular cargo, ability to mediate intercellular communication, high physicochemical stability, low immunogenicity and biocompatibility. The theranostic potential of EVs have been enhanced by adopting several strategies such as genetic or metabolic engineering, parental cell modification or direct functionalization to incorporate therapeutic compounds into these nanoplatforms. The smart nano-sized EVs indeed offer huge opportunities in the field of cancer, and current research is set at overcoming the existing pitfalls. Smart EVs are already being applied in the clinics despite the challenges faced. We provide, herein, an update on the technologies employed for EV functionalization in order to achieve optimal tumor cell targeting and EV tracking in vivo with bio-imaging modalities, as well as the preclinical and clinical studies making use of these modified EVs, in the context of gastrointestinal tumors.

MicroRNA-22 Is a Key Regulator of Lipid and Metabolic Homeostasis.

Obesity is a growing public health problem associated with increased risk of type 2 diabetes, cardiovascular disease, nonalcoholic fatty liver disease (NAFLD) and cancer. Here, we identify microRNA-22 (miR-22) as an essential rheostat involved in the control of lipid and energy homeostasis as well as the onset and maintenance of obesity. We demonstrate through knockout and transgenic mouse models that miR-22 loss-of-function protects against obesity and hepatic steatosis, while its overexpression promotes both phenotypes even when mice are fed a regular chow diet. Mechanistically, we show that miR-22 controls multiple pathways related to lipid biogenesis and differentiation. Importantly, genetic ablation of miR-22 favors metabolic rewiring towards higher energy expenditure and browning of white adipose tissue, suggesting that modulation of miR-22 could represent a viable therapeutic strategy for treatment of obesity and other metabolic disorders.

Role of available COVID-19 vaccines in reducing deaths and perspective for next generation vaccines and therapies to counter emerging viral variants: an update.

The COVID-19 disease wreaked havoc all over the world causing more than 6 million deaths out of over 519 million confirmed cases. It not only disturbed the human race health-wise but also caused huge economic losses and social disturbances. The utmost urgency to counter pandemic was to develop effective vaccines as well as treatments that could reduce the incidences of infection, hospitalization and deaths. The most known vaccines that could help in managing these parameters are Oxford-AstraZeneca (AZD1222), Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273) and Johnson & Johnson (Ad26.COV2.S). The effectiveness of AZD1222 vaccine in reducing deaths is 88% in the age group 40-59 years, touching 100% in the age group 16-44 years & 65-84 years. BNT162b2 vaccine also did well in reducing deaths due to COVID-19 (95% in the age group 40-49 years and 100% in the age group 16-44 years. Similarly, mRNA-1273 vaccine showed potential in reducing COVID-19 deaths with effectiveness ranging from 80.3 to 100% depending upon age group of the vaccinated individuals. Ad26.COV2.S vaccine was also 100% effective in reducing COVID-19 deaths. The SARS-CoV-2 emerging variants have emphasized the need of booster vaccine doses to enhance protective immunity in vaccinated individuals. Additionally, therapeutic effectiveness of Molnupiravir, Paxlovid and Evusheld are also providing resistance against the spread of COVID-19 disease as well as may be effective against emerging variants. This review highlights the progress in developing COVID-19 vaccines, their protective efficacies, advances being made to design more efficacious vaccines, and presents an overview on advancements in developing potent drugs and monoclonal antibodies for countering COVID-19 and emerging variants of SARS-CoV-2 including the most recently emerged and highly mutated Omicron variant.

Autoimmune Hepatitis and Fibrosis.

Autoimmune hepatitis (AIH) is a chronic immune-inflammatory disease of the liver, generally considered a rare condition. The clinical manifestation is extremely varied and can range from paucisymptomatic forms to severe hepatitis. Chronic liver damage causes activation of hepatic and inflammatory cells leading to inflammation and oxidative stress through the production of mediators. This results in increased collagen production and extracellular matrix deposition leading to fibrosis and even cirrhosis. The gold standard for the diagnosis of fibrosis is liver biopsy; however, there are serum biomarkers, scoring systems, and radiological methods useful for diagnosis and staging. The goal of AIH treatment is to suppress fibrotic and inflammatory activities in the liver to prevent disease progression and achieve complete remission. Therapy involves the use of classic steroidal anti-inflammatory drugs and immunosuppressants, but in recent years scientific research has focused on several new alternative drugs for AIH that will be discussed in the review.

Association between intestinal microflora and obesity.

Obesity has become one of modern society's most serious health problems. Studies from the last 30 years revealed a direct relationship between imbalanced energy intake and increased healthcare costs related to the treatment or management of obesity. Recent research has highlighted significant effects of gut microbial composition on obesity. We aimed to report the current knowledge on the definition, composition, and functions of intestinal microbiota. We have performed an extensive review of the literature searching for the following key words: metabolism, gut microbiota, dysbiosis, and obesity. There is evidence that an association between intestinal microbiota and obesity exists at any age. There are complex genetic, metabolic, and inflammatory mechanisms involved in the pathogenesis of obesity. Revision of indications for use of probiotics, prebiotics, and antibiotics in obese patients should be considered. Microbial composition of the gut may be an important factor involved in the development of obesity. Changes in the gut microbiota may result in changes in human metabolism and weight loss.

Combined effect of ipilimumab and nivolumab improves oncology endpoints in metastatic melanoma patients.

Metastatic melanoma has less frequency, but considered as the most dreaded cancer. The combination of nivolumab & ipilimumab is proving their mettle in treating metastatic melanoma. The patients when administered with the combination of nivolumab & ipilimumab have shown improved median progression free survival, objective response rate and overall survival rate compared with nivolumab and ipilimumab monotherapy. The combination shrinks the tumor cells by attacking different checkpoints viz. CTLA-4 and PD-L1, respectively. The combination treatment reveals reduced disease progression and suggests nivolumab's non-cross resistant nature. The median progression free survival in "nivolumab plus ipilimumab" group has shown an increase of 66.7% and 296.6% in comparison to nivolumab and ipilimumab monotherapy. The other parameter viz. objective response rate improvement is equivalent to almost 14% and 38.6% when compared to nivolumab and ipilimumab monotherapy, respectively.

Diet as a modifiable factor in tumorigenesis: Focus on microbiome-derived bile acid metabolites and short-chain fatty acids.

Several lines of evidences have implicated the resident microbiome as a key factor in the modulation of host physiology and pathophysiology; including the resistance to cancers. Gut microbiome heavily influences host lipid homeostasis by their modulatory effects on the metabolism of bile acids (BAs). Microbiota-derived BA metabolites such as deoxycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) are implicated in the pathogeneses of various cancer types. The pathogenic mechanisms are multimodal in nature, with widespread influences on the host immunes system, cell survival and growth signalling and DNA damage. On the other hand, short-chain fatty acids (SCFAs) produced by the resident microbial activity on indigestible dietary fibres as well as during intermittent fasting regimens (such as the Ramazan fasting) elicit upregulation of the beneficial anti-inflammatory and anticancer pathways in the host. The present review first provides a brief overview of the molecular mechanisms of microbiota-derived lipid metabolites in promotion of tumour development. The authors then discuss the potential of diet as a therapeutic route for beneficial alteration of microbiota and the consequent changes in the production of SCFAs, particularly butyrate, in relation to the cancer prevention and treatment.

Phenotypic and functional characterization of aqueous humor derived extracellular vesicles.

Extracellular vesicles (EVs) are double membrane vesicles, abundant in all biological fluids. However, the characterization of EVs in aqueous humor (AH) is still limited. The aim of the present work was to characterize EVs isolated from AH (AH-EVs) in terms of surface markers of cellular origin and functional properties. We obtained AHs from patients with cataract undergoing surgical phacoemulsification and insertion of intraocular lenses (n = 10). Nanoparticle tracking analysis, electron microscopy, super resolution microscopy and bead-based cytofluorimetry were used to characterize EVs from AH. Subsequently, we investigated the effects of AH-EVs on viability, proliferation and wound healing of human immortalized keratinocyte (HaCaT) cells in vitro in comparison with the effect of mesenchymal stromal cell-EVs (MSC-EVs). AH-EVs had a mean size of around 100 nm and expressed the classical tetraspanins (CD9, CD63 and CD81). Super resolution microscopy revealed co-expression of CD9, CD63 and CD81. Moreover, cytofluorimetric analysis highlighted the expression of mesenchymal, stem, epithelial and endothelial markers. In the in vitro wound healing assay on HaCaT cells, AH-EVs induced a significantly faster wound repair, comparable to the effects of MSC-EVs, and promoted HaCaT cell viability and proliferation. We provide evidence, herein, of the possible AH-EV origin from stromal cells, limbal epithelial/stem cells, ciliary epithelium and corneal endothelium. In addition, we showed their in vitro proliferative and regenerative capacities.

Modulation of the gut microbiota: opportunities and regulatory aspects.

The human gut is an intensively colonized organ containing microorganisms that can be health-promoting or pathogenic. This feature led to the development of functional foods aiming to fortify the former category at the expense of the latter. Since long, cultured products, including probiotics fortification, have been used for humans as live microbial feed additions. This review presents some of the microbes used as probiotics and discusses how supplementation with probiotics may help initiate and/or restore eubiotic composition of gut microbiota. Additionally, it considers safety and regulatory aspects of probiotics.

COVID-19 and the enteric system: rapidly propagating issues.

The newly described SARS-CoV-2 respiratory virus is now righteously presenting as an ominous threat, based on the speed with which it originated a zoonosis from bats; advancing at a similar rate, the virus has placed mankind before a pandemic, with an infection toll of some 431 million, and a lethality of 5,9 million (as of February 25, 2022). The size of the harm that this agent can unleash against us is appallingly wide, from brain ischemia to foot chilblain, passing by heart massive infarction. Designing a possible response, we reappraised the well-known equation depression-inflammation, and tested the hypothesis that an upgraded ease-of-mind might help reduce the host's hospitality towards SARS-CoV-2. With time passing, it becomes increasingly evident that the virus shall tend to progressively occupy spaces, replacing pandemics with an apparently calm endemicity. This will have to be avoided, and surveillance of society on psychological terms will be one tenet. Needless to say, the role of the enteric tract in these issues is growing higher, and it will be narrated to seal the matters with the last (not the least) touch of glue.

Triglyceride-Glucose Index and Hepatic Steatosis Index for the assessment of liver steatosis in HCV patients.

BACKGROUND: Liver steatosis in patients with chronic infection of hepatitis C virus (HCV) is important from multiple standpoints: faster disease progression, more frequent hepatocellular carcinoma and cirrhosis development or worse therapy response. Liver biopsy as diagnostic method, is in recent years more and more challenged due to its well-known flaws. Hepatic steatosis index (HSI) and triglyceride-glucose (TyG) Index, are surrogate scores developed in the first place for noninvasive assessment of steatosis in patients with nonalcoholic fatty liver disease (NAFLD). However, their use in the context of chronic hepatitis C (CHC) virus infection is still unclear. Aim of our study was to assess the accuracy of both HSI and TyG index in patients with CHC. METHODS: The cohort included 814 patients with CHC infection in whom liver biopsy was performed. After implementing strict criteria for sample adequacy and necessary data, 424 patients were finally enrolled in our study. Histological findings were used as a reference point, and surrogate scores HSI and TyG index were expressed through receiver operating characteristic (ROC) curves in order to assess their ability in determining patients without (<5%) or with steatosis (>5%), but also to address their ability in assessing between different degrees of steatosis. RESULTS: The average age of study population was 37.09 years and the majority of patients were men (67%). Liver steatosis was detected in approximately half of the liver biopsy samples (50.4%). About 5% of them had severe steatosis. The area under the ROC curve values for HSI and TyG index when detecting liver steatosis were 0.76 and 0.629, respectively. Similar values were obtained comparing between absence of steatosis and mild steatosis (5-30%). CONCLUSIONS: Non-invasive surrogate scores HSI and TyG index in CHC patients, have good performance to detect the presence of steatosis. In this context, these tools are cheap, widely available and could be valuable asset in liver steatosis assessment outside liver biopsy.

Liver injury associated with high value of D-dimer plasmatic level in COVID-19 patients.

BACKGROUND: The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), causal agent of the coronavirus disease (COVID-19), has infected millions of people worldwide. Currently, the scientific community debates on the direct viral responsibility of liver damage or whether the observed changes are secondary manifestations of systemic inflammation triggered by COVID-19. The hepatic involvement is associated with worse clinical outcomes and higher risk of COVID-19 related morbidity and mortality. Furthermore, SARS-CoV-2 infection may predispose patients to thrombotic disease due to excessive inflammation, platelet activation, and endothelial dysfunction. METHODS: In this paper, we reported a cross-sectional analysis of five patients affected by a severe form of COVID-19, who died between April 11 and May 1, 2020. Each patient has been subjected to a medico-legal autopsy in which both gross and histological liver changes were evaluated, as well as the correlation with the related coagulation profile. RESULTS: In three cases of our cohort, the thromboembolism was recognized as cause of death. Furthermore, a significant statistical difference between D-dimer values at hospital admission and death among enrolled patients (P=0.033), was evaluated. No patient has recorded a pre-existing liver disease. CONCLUSIONS: Our results support the evidence that hepatic damage in subjects with severe form of COVID-19 is related to the changes in coagulative and fibrinolytic pathways. Hence, the evaluation of D-dimer blood levels may be useful in clinical practice to predict the involvement of the liver and the prognosis of these patients. This data highlights the fundamental role of coagulation balance in subjects with advanced form of COVID-19.

Bone Marrow Mesenchymal Stromal/Stem Cell-Derived Extracellular Vesicles Promote Corneal Wound Repair by Regulating Inflammation and Angiogenesis.

Severe corneal damage leads to complete vision loss, thereby affecting life quality and impinging heavily on the healthcare system. Current clinical approaches to manage corneal wounds suffer from severe drawbacks, thus requiring the development of alternative strategies. Of late, mesenchymal stromal/stem cell (MSC)-derived extracellular vesicles (EVs) have become a promising tool in the ophthalmic field. In the present study, we topically delivered bone-marrow-derived MSC-EVs (BMSC-EVs), embedded in methylcellulose, in a murine model of alkali-burn-induced corneal damage in order to evaluate their role in corneal repair through histological and molecular analyses, with the support of magnetic resonance imaging. Our data show that BMSC-EVs, used for the first time in this specific formulation on the damaged cornea, modulate cell death, inflammation and angiogenetic programs in the injured tissue, thus leading to a faster recovery of corneal damage. These results were confirmed on cadaveric donor-derived human corneal epithelial cells in vitro. Thus, BMSC-EVs modulate corneal repair dynamics and are promising as a new cell-free approach for intervening on burn wounds, especially in the avascularized region of the eye.

Smart Nanoformulations for Brain Cancer Theranostics: Challenges and Promises.

Despite their low prevalence, brain tumors are among the most lethal cancers. They are extremely difficult to diagnose, monitor and treat. Conventional anti-cancer strategies such as radio- and chemotherapy have largely failed, and to date, the development of even a single effective therapeutic strategy against central nervous system (CNS) tumors has remained elusive. There are several factors responsible for this. Brain cancers are a heterogeneous group of diseases with variable origins, biochemical properties and degrees of invasiveness. High-grade gliomas are amongst the most metastatic and invasive cancers, which is another reason for therapeutic failure in their case. Moreover, crossing the blood brain and the blood brain tumor barriers has been a significant hindrance in the development of efficient CNS therapeutics. Cancer nanomedicine, which encompasses the application of nanotechnology for diagnosis, monitoring and therapy of cancers, is a rapidly evolving field of translational medicine. Nanoformulations, because of their extreme versatility and manipulative potential, are emerging candidates for tumor targeting, penetration and treatment in the brain. Moreover, suitable nanocarriers can be commissioned for theranostics, a combinatorial personalized approach for simultaneous imaging and therapy. This review first details the recent advances in novel bioengineering techniques that provide promising avenues for circumventing the hurdles of delivering the diagnostic/therapeutic agent to the CNS. The authors then describe in detail the tremendous potential of utilizing nanotechnology, particularly nano-theranostics for brain cancer imaging and therapy, and outline the different categories of recently developed next-generation smart nanoformulations that have exceptional potential for making a breakthrough in clinical neuro-oncology therapeutics.

Expression of SARS-Cov-2 Entry Factors in Patients with Chronic Hepatitis.

Chronic hepatitis (CH) of dysmetabolic or viral etiology has been associated with poor prognosis in patients who experienced the severe acute respiratory coronavirus virus-2 (SARS-Cov-2) infection. We aimed to explore the impact of SARS-Cov-2 infection on disease severity in a group of patients with CH. Forty-two patients with CH of different etiology were enrolled (median age, 56 years; male gender, 59%). ACE2 and TMPRSS2 were measured in plasma samples of all patients by ELISA and in the liver tissue of a subgroup of 15 patients by Western blot. Overall, 13 patients (31%) experienced SARS-Cov-2 infection: 2/15 (15%) had CHB, 5/12 (39%) had CHC, and 6/15 (46%) had non-alcoholic fatty liver disease (NAFLD). Compared to viral CH patients, NAFLD subjects showed higher circulating ACE2 levels (p = 0.0019). Similarly, hepatic expression of ACE2 was higher in subjects who underwent SARS-Cov-2 infection compared to the counterpart, (3.24 ± 1.49 vs. 1.49 ± 1.32, p = 0.032). Conversely, hepatic TMPRSS2 was significantly lower in patients who experienced symptomatic COVID-19 disease compared to asymptomatic patients (p = 0.0038). Further studies are necessary to understand the impact of COVID-19 in patients with pre-existing liver diseases.