Metabolic-Associated Fatty Liver Disease Is Highly Prevalent in the Postacute COVID Syndrome

Possible link between steatotic liver diseases, severe COVID-19 and cognitive impairment in post-COVID-19 syndrome

PURPOSE

Steatotic liver diseases (SLD) have become more prevalent over the last decade and are associated not only with cardiometabolic diseases but also with psychological symptoms (depression, fatigue). These symptoms are also common in post-COVID syndrome (PCS). Therefore, the aim of the study was to analyze the burden of SLD in PCS patients.

METHODS

We systematically screened all PCS patients from our post-COVID outpatient clinic using transient elastography, structured questionnaires for neurocognitive evaluation and blood sample analysis. Controls without PCS and without known liver diseases were also recruited and assessed with the same approach.

RESULTS

560 PCS patients and 103 healthy controls were included. The overall prevalence of SLD was high in both cohorts (57 vs. 53%). PCS patients with SLD were more frequently male (41 vs. 24%), older (52 vs. 44 years) and had more cardiometabolic diseases (87.0 vs. 46.4%). Cognitive impairment was more related to SLD in PCS patients than in the no-SLD group (OR: 1.68, CI: 1.14-2.46, p = 0.008). The presence of SLD was related to severe COVID-19 with hospitalization (OR: 2.91, CI: 1.85-4.56, p < 0.001). Within 1 year of the follow-up, 152 of 289 patients described a resolution in PCS irrespective of the presence or absence of SLD (log-rank p = 0.96).

CONCLUSIONS

SLD is associated with severe COVID-19 and cognitive dysfunction in PCS. Longitudinal studies are needed to assess the role of hepatic steatosis, development of post-acute infection regulation (e.g., SARS-CoV-2) and to differentiate between SLD-associated symptoms and PCS.

New Onset of Acute and Chronic Hepatic Diseases Post-COVID-19 Infection: A Systematic Review

The SARS-CoV-2 virus caused a pandemic in the 2020s, which affected almost every aspect of life. As the world is recovering from the effect of the coronavirus, the concept of post-COVID-19 syndrome has emerged. Multiple organ systems have been implicated, including the liver. We aim to identify and analyze the reported cases of severe and long-term parenchymal liver injury post-COVID-19 infection. Several databases were used to conduct a comprehensive literature search to target studies reporting cases of severe and long-term parenchymal liver injury post-COVID-19 infection. Screening, data extraction, and cross checking were performed by two independent reviewers. Only 22 studies met our inclusion criteria. Our results revealed that liver steatosis, non-alcoholic fatty liver disease (NAFLD), and cirrhosis were the most reported liver associated complications post-COVID-19 infection. Moreover, complications like acute liver failure, hepatitis, and liver hemorrhage were also reported. The mechanism of liver injury post-COVID-19 infection is not fully understood. The leading proposed mechanisms include the involvement of the angiotensin-converting enzyme-2 (ACE-2) receptor expressed in the liver and the overall inflammatory state caused by COVID-19 infection. Future studies should incorporate longer follow-up periods, spanning several years, for better insight into the progression and management of such diseases.

Impact of non-alcoholic fatty liver disease on coronavirus disease 2019: A systematic review

BACKGROUND

Many studies have revealed a link between non-alcoholic fatty liver disease (NAFLD) and coronavirus disease 2019 (COVID-19), making understanding the relationship between these two conditions an absolute requirement.

AIM

To provide a qualitative synthesis on the currently present data evaluating COVID-19 and NAFLD.

METHODS

This systematic review was conducted in accordance with the guidelines provided by preferred reporting items for systematic reviews and meta-analyses and the questionnaire utilized the population, intervention, comparison, and outcome framework. The search strategy was run on three separate databases, PubMed/MEDLINE, Scopus, and Cochrane Central, which were systematically searched from inception until March 2024 to select all relevant studies. In addition, ClinicalTrials.gov, Medrxiv.org, and Google Scholar were searched to identify grey literature.

RESULTS

After retrieval of 11 studies, a total of 39282 patients data were pooled. Mortality was found in 11.5% and 9.4% of people in NAFLD and non-NAFLD groups. In all, 23.2% of NAFLD patients and 22% of non-NAFLD admissions diagnosed with COVID-19 were admitted to the intensive care unit, with days of stay varying. Ventilatory support ranged from 5% to 40.5% in the NAFLD cohort and from 3.1% to 20% in the non-NAFLD cohort. The incidence of acute liver injury showed significance. Clinical improvement on days 7 and 14 between the two classifications was significant. Hospitalization stay ranged from 9.6 days to 18.8 days and 7.3 days to 16.4 days in the aforementioned cohorts respectively, with 73.3% and 76.3% of patients being discharged. Readmission rates varied.

CONCLUSION

Clinical outcomes except mortality consistently showed a worsening trend in patients with NAFLD and concomitant COVID-19. Further research in conducting prospective longitudinal studies is essential for a more powerful conclusion.

Insight into COVID-19 associated liver injury: Mechanisms, evaluation, and clinical implications

COVID-19 has affected millions worldwide, causing significant morbidity and mortality. While predominantly involving the respiratory tract, SARS-CoV-2 has also caused systemic illnesses involving other sites. Liver injury due to COVID-19 has been variably reported in observational studies. It has been postulated that liver damage may be due to direct damage by the SARS-CoV-2 virus or multifactorial secondary to hepatotoxic therapeutic options, as well as cytokine release syndrome and sepsis-induced multiorgan dysfunction. The approach to a COVID-19 patient with liver injury requires a thorough evaluation of the pattern of hepatocellular injury, along with the presence of underlying chronic liver disease and concurrent medications which may cause drug-induced liver injury. While studies have shown uneventful recovery in the majority of mildly affected patients, severe COVID-19 associated liver injury has been associated with higher mortality, prolonged hospitalization, and greater morbidity in survivors. Furthermore, its impact on long-term outcomes remains to be ascertained as recent studies report an association with metabolic-fatty liver disease. This present review provides insight into the subject by describing the postulated mechanism of liver injury, its impact in the presence of pre-existing liver disease, and its short- and long-term clinical implications.

Steatotic Liver Disease: Pathophysiology and Emerging Pharmacotherapies

Steatotic liver disease (SLD) displays a dynamic and complex disease phenotype. Consequently, the metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) therapeutic pipeline is expanding rapidly and in multiple directions. In parallel, noninvasive tools for diagnosing and monitoring responses to therapeutic interventions are being studied, and clinically feasible findings are being explored as primary outcomes in interventional trials. The realization that distinct subgroups exist under the umbrella of SLD should guide more precise and personalized treatment recommendations and facilitate advancements in pharmacotherapeutics. This review summarizes recent updates of pathophysiology-based nomenclature and outlines both effective pharmacotherapeutics and those in the pipeline for MASLD/MASH, detailing their mode of action and the current status of phase 2 and 3 clinical trials. Of the extensive arsenal of pharmacotherapeutics in the MASLD/MASH pipeline, several have been rejected, whereas other, mainly monotherapy options, have shown only marginal benefits and are now being tested as part of combination therapies, yet others are still in development as monotherapies. Although the Food and Drug Administration (FDA) has recently approved resmetirom, additional therapeutic approaches in development will ideally target MASH and fibrosis while improving cardiometabolic risk factors. Due to the urgent need for the development of novel therapeutic strategies and the potential availability of safety and tolerability data, repurposing existing and approved drugs is an appealing option. Finally, it is essential to highlight that SLD and, by extension, MASLD should be recognized and approached as a systemic disease affecting multiple organs, with the vigorous implementation of interdisciplinary and coordinated action plans. SIGNIFICANCE STATEMENT: Steatotic liver disease (SLD), including metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, is the most prevalent chronic liver condition, affecting more than one-fourth of the global population. This review aims to provide the most recent information regarding SLD pathophysiology, diagnosis, and management according to the latest advancements in the guidelines and clinical trials. Collectively, it is hoped that the information provided furthers the understanding of the current state of SLD with direct clinical implications and stimulates research initiatives.

Diabetes Mellitus, Energy Metabolism, and COVID-19

Obesity, diabetes mellitus (mostly type 2), and COVID-19 show mutual interactions because they are not only risk factors for both acute and chronic COVID-19 manifestations, but also because COVID-19 alters energy metabolism. Such metabolic alterations can lead to dysglycemia and long-lasting effects. Thus, the COVID-19 pandemic has the potential for a further rise of the diabetes pandemic. This review outlines how preexisting metabolic alterations spanning from excess visceral adipose tissue to hyperglycemia and overt diabetes may exacerbate COVID-19 severity. We also summarize the different effects of SARS-CoV-2 infection on the key organs and tissues orchestrating energy metabolism, including adipose tissue, liver, skeletal muscle, and pancreas. Last, we provide an integrative view of the metabolic derangements that occur during COVID-19. Altogether, this review allows for better understanding of the metabolic derangements occurring when a fire starts from a small flame, and thereby help reducing the impact of the COVID-19 pandemic.

Hyperammonemia as a manifestation of post-covid syndrome in patients with nonalcoholic fatty liver disease: post-hoc analysis of the LIRA - COVID observational clinical program

Post-Covid syndrome (PCS) is considered as a consequence of a previous coronavirus infection. The liver in COVID-19 is one of the most frequently affected organs, with the development of asthenia, cognitive impairment, as well as increased activity of alanine and aspartic transaminases (ALT and AST), which persist in some patients up to 4-6 months after discharge from the hospital. The cause of asthenia may be hyperammonemia (HA), which in COVID-19 is a manifestation of liver dysfunction against the background of the direct cytotoxic effect of SARS-CoV-2 on hepatocytes, which was previously shown as part of the clinical observational program protocol “LIRA - COVID”. Due to the great relevance of the problem of the combination of PCS, non-alcoholic fatty liver disease (NAFLD) and HA a post-hoc analysis of the observational clinical program LIRA - COVID was carried out. It was shown that NAFLD has a significant effect on the level of AST before the start of treatment with L-ornithine - L-aspartate (LOLA). The presence of NAFLD has a significant effect on ammonia levels after 14 days of treatment, since in the group of patients with NAFLD the ammonia level was significantly higher than in the group without NAFLD. It was concluded that it is advisable to include in the examination scheme of patients with PCS and NAFLD, determination of the level of ammonia in the blood, when elevated, the administration of the drug to such patients is justified LOLA course for 4 weeks at a standard dose of 9 g per day.

Mortality Increased Among Hospitalized Patients with Cirrhosis Before and Following Different Waves of the COVID-19 Pandemic

BACKGROUND

The Coronavirus disease 2019 (COVID-19) pandemic disrupted patient care and worsened the morbidity and mortality of some chronic diseases. The impact of the COVID-19 pandemic on hospitalizations and outcomes in patients with cirrhosis both before and during different time periods of the pandemic has not been evaluated.

AIMS

Describe characteristics of hospitalized patients with cirrhosis and evaluate inpatient mortality and 30-day readmission before and after the start of the COVID-19 pandemic.

METHODS

Retrospective single-center cohort study of all hospitalized patients with cirrhosis from 2018 to 2022. Time periods within the COVID-19 pandemic were defined using reference data from the World Health Organization and Centers for Disease Control. Adjusted odds ratios from logistic regression were used to assess differences between periods.

RESULTS

33,926 unique hospitalizations were identified. Most patients were over age 60 years across all time periods of the pandemic. More Hispanic patients were hospitalized during COVID-19 than before COVID-19. Medicare and Medicaid are utilized less frequently during COVID-19 than before COVID-19. After controlling for age and gender, inpatient mortality was significantly higher during all COVID-19 periods except Omicron compared to before COVID-19. The odds of experiencing a 30-day readmission were 1.2 times higher in the pre-vaccination period compared to the pre-COVID-19 period.

CONCLUSION

Inpatient mortality among patients with cirrhosis has increased during the COVID-19 pandemic compared to before COVID-19. Although COVID-19 infection may have had a small direct pathologic effect on the natural history of cirrhotic liver disease, it is more likely that other factors are impacting this population.

Nonalcoholic fatty liver disease and insulin resistance in children

Nonalcoholic fatty liver disease (NAFLD), a spectrum of liver diseases characterized by excessive fat accumulation, is the leading cause of chronic liver disease. The global prevalence of NAFLD is increasing in both adults and children. In Korea, the prevalence of pediatric NAFLD increased from 8.2% in 2009 to 12.1% in 2018 according to a national surveillance study. For early screening of pediatric NAFLD, laboratory tests including aspartate aminotransferase and alanine aminotransferase; biomarkers including hepatic steatosis index, triglyceride glucose index, and fibrosis-4 index; and imaging studies including ultrasonography and magnetic resonance imaging are required. Insulin resistance plays a major role in the pathogenesis of NAFLD, which promotes insulin resistance. Thus, the association between NAFLD and insulin resistance, diabetes mellitus, and metabolic syndrome has been reported in many studies. This review addresses issues related to the epidemiology and investigation of NAFLD as well as the association between NAFLD and insulin resistance and metabolic syndrome with focus on pediatric NAFLD.

Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID?

Both myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) and long COVID (LC) are characterized by similar immunological alterations, persistence of chronic viral infection, autoimmunity, chronic inflammatory state, viral reactivation, hypocortisolism, and microclot formation. They also present with similar symptoms such as asthenia, exercise intolerance, sleep disorders, cognitive dysfunction, and neurological and gastrointestinal complaints. In addition, both pathologies present Epstein-Barr virus (EBV) reactivation, indicating the possibility of this virus being the link between both pathologies. Therefore, we propose that latency and recurrent EBV reactivation could generate an acquired immunodeficiency syndrome in three steps: first, an acquired EBV immunodeficiency develops in individuals with "weak" EBV HLA-II haplotypes, which prevents the control of latency I cells. Second, ectopic lymphoid structures with EBV latency form in different tissues (including the CNS), promoting inflammatory responses and further impairment of cell-mediated immunity. Finally, immune exhaustion occurs due to chronic exposure to viral antigens, with consolidation of the disease. In the case of LC, prior to the first step, there is the possibility of previous SARS-CoV-2 infection in individuals with "weak" HLA-II haplotypes against this virus and/or EBV.

COVID-19 and Liver Disease: An Evolving Landscape

The COVID-19 pandemic has resulted in significant worldwide morbidity and mortality. In this review, we examine the intricate relationships between COVID-19 and liver diseases. While respiratory manifestations of COVID-19 are well known, its impact and consequences in patients with liver diseases remain an area of ongoing investigation. COVID-19 can induce liver injury through various mechanisms and is associated with higher mortality in individuals with preexisting chronic liver disease. Mortality increases with the severity of chronic liver disease and the level of care required. The outcomes in patients with autoimmune hepatitis remain unclear, whereas liver transplant recipients are more likely to experience symptomatic COVID-19 but have comparable outcomes to the general population. Despite suboptimal immunological response, COVID-19 vaccinations are safe and effective in liver disease, although cases of autoimmune hepatitis-like syndrome have been reported. In conclusion, COVID-19 has significant implications in liver diseases; early recognition and treatments are important for improving patient outcomes.

The Role of Gut Dysbiosis in the Loss of Intestinal Immune Cell Functions and Viral Pathogenesis

The gut microbiome plays a critical role in maintaining overall health and immune function. However, dysbiosis, an imbalance in microbiome composition, can have profound effects on various aspects of human health, including susceptibility to viral infections. Despite numerous studies investigating the influence of viral infections on gut microbiome, the impact of gut dysbiosis on viral infection and pathogenesis remains relatively understudied. The clinical variability observed in SARS-CoV-2 and seasonal influenza infections, and the presence of natural HIV suppressors, suggests that host-intrinsic factors, including the gut microbiome, may contribute to viral pathogenesis. The gut microbiome has been shown to influence the host immune system by regulating intestinal homeostasis through interactions with immune cells. This review aims to enhance our understanding of how viral infections perturb the gut microbiome and mucosal immune cells, affecting host susceptibility and response to viral infections. Specifically, we focus on exploring the interactions between gamma delta (γδ) T cells and gut microbes in the context of inflammatory viral pathogenesis and examine studies highlighting the role of the gut microbiome in viral disease outcomes. Furthermore, we discuss emerging evidence and potential future directions for microbiome modulation therapy in the context of viral pathogenesis.

Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19

Long COVID, also known for post-acute sequelae of COVID-19, describes the people who have the signs and symptoms that continue or develop after the acute COVID-19 phase. Long COVID patients suffer from an inflammation or host responses towards the virus approximately 4 weeks after initial infection with the SARS CoV-2 virus and continue for an uncharacterized duration. Anyone infected with COVID-19 before could experience long-COVID conditions, including the patients who were infected with SARS CoV-2 virus confirmed by tests and those who never knew they had an infection early. People with long COVID may experience health problems from different types and combinations of symptoms over time, such as fatigue, dyspnea, cognitive impairments, and gastrointestinal (GI) symptoms (e.g., nausea, vomiting, diarrhea, decreased or loss of appetite, abdominal pain, and dysgeusia). The critical role of the microbiome in these GI symptoms and long COVID were reported in clinical patients and experimental models. Here, we provide an overall view of the critical role of the GI tract and microbiome in the development of long COVID, including the clinical GI symptoms in patients, dysbiosis, viral-microbiome interactions, barrier function, and inflammatory bowel disease patients with long COVID. We highlight the potential mechanisms and possible treatment based on GI health and microbiome. Finally, we discuss challenges and future direction in the long COVID clinic and research.

Gastrointestinal disorders in post-COVID syndrome. Clinical guidelines

Summary Post- COVID syndrome refers to the long-term consequences of a new coronavirus infection COVID-19, which includes a set of symptoms that develop or persist after COVID-19. Symptoms of gastrointestinal disorders in post- COVID syndrome, due to chronic infl ammation, the consequences of organ damage, prolonged hospitalization, social isolation, and other causes, can be persistent and require a multidisciplinary approach. The presented clinical practice guidelines consider the main preventive and therapeutic and diagnostic approaches to the management of patients with gastroenterological manifestations of postCOVID syndrome. The Guidelines were approved by the 17th National Congress of Internal Medicine and the 25th Congress of Gastroenterological Scientifi c Society of Russia.

Changes in the Prevalences of Obesity, Abdominal Obesity, and Non-Alcoholic Fatty Liver Disease among Korean Children during the COVID-19 Outbreak

PURPOSE

We aimed to investigate the prevalences of obesity, abdominal obesity, and non-alcoholic fatty liver disease (NAFLD) among children and adolescents during the coronavirus disease 2019 (COVID-19) outbreak.

MATERIALS AND METHODS

This population-based study investigated the prevalences of obesity, abdominal obesity, and NAFLD among 1428 children and adolescents between 2018-2019 and 2020. We assessed the prevalences of obesity, abdominal obesity, and NAFLD according to body mass index, age, sex, and residential district. Logistic regression analyses were performed to determine the relationships among obesity, abdominal obesity, and NAFLD.

RESULTS

In the obese group, the prevalence of abdominal obesity increased from 75.55% to 92.68%, and that of NAFLD increased from 40.68% to 57.82%. In age-specific analysis, the prevalence of abdominal obesity increased from 8.25% to 14.11% among participants aged 10-12 years and from 11.70% to 19.88% among children aged 13-15 years. In residential district-specific analysis, the prevalence of both abdominal obesity and NAFLD increased from 6.96% to 15.74% in rural areas. In logistic regression analysis, the odds ratio of abdominal obesity for NAFLD was 11.82.

CONCLUSION

Our results demonstrated that the prevalences of abdominal obesity and NAFLD increased among obese Korean children and adolescents and in rural areas during the COVID-19 outbreak. Additionally, the prevalence of abdominal obesity increased among young children. These findings suggest the importance of closely monitoring abdominal obesity and NAFLD among children during COVID-19, focusing particularly on obese young children and individuals in rural areas.

Sequelae of long COVID, known and unknown: A review of updated information

Over three years have passed since the COVID-19 pandemic started. The dangerousness and impact of COVID-19 should definitely not be ignored or underestimated. Other than the symptoms of acute infection, the long-term symptoms associated with SARS-CoV-2 infection, which are referred to here as "sequelae of long COVID (LC)", are also a conspicuous global public health concern. Although such sequelae were well-documented, the understanding of and insights regarding LC-related sequelae remain inadequate due to the limitations of previous studies (the follow-up, methodological flaws, heterogeneity among studies, etc.). Notably, robust evidence regarding diagnosis and treatment of certain LC sequelae remain insufficient and has been a stumbling block to better management of these patients. This awkward situation motivated us to conduct this review. Here, we comprehensively reviewed the updated information, particularly focusing on clinical issues. We attempt to provide the latest information regarding LC-related sequelae by systematically reviewing the involvement of main organ systems. We also propose paths for future exploration based on available knowledge and the authors' clinical experience. We believe that these take-home messages will be helpful to gain insights into LC and ultimately benefit clinical practice in treating LC-related sequelae.

Chronic liver disease-related mortality in diabetes before and during the COVID-19 in the United States

BACKGROUND

Global pandemic of COVID-19 represents an unprecedented challenge. COVID-19 has predominantly targeted vulnerable populations with pre-existing chronic medical diseases, such as diabetes and chronic liver disease.

AIMS

We estimated chronic liver disease-related mortality trends among individuals with diabetes before and during the COVID-19 pandemic.

METHODS

Utilizing the US national mortality database and Census, we determined the quarterly age-standardized chronic liver disease-related mortality and quarterly percentage change (QPC) among individuals with diabetes.

RESULTS

The quarterly age-standardized mortality for chronic liver disease and/or cirrhosis among individuals with diabetes remained stable before the COVID-19 pandemic and sharply increased during the COIVD-19 pandemic at a QPC of 8.5%. The quarterly mortality from nonalcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD) increased markedly during the COVID-19 pandemic. Mortality for hepatitis C virus (HCV) infection declined with a quarterly rate of -3.3% before the COVID-19 pandemic and remained stable during the COVID-19 pandemic. While ALD- and HCV-related mortality was higher in men than in women, NAFLD-related mortality in women was higher than in men.

CONCLUSIONS

The sharp increase in mortality for chronic liver disease and/or cirrhosis among individuals with diabetes during the COVID-19 pandemic was associated with increased mortality from NAFLD and ALD.

The interplay of post-acute COVID-19 syndrome and aging: a biological, clinical and public health approach

The post-acute COVID-19 syndrome (PACS) is characterized by the persistence of fluctuating symptoms over three months from the onset of the possible or confirmed COVID-19 acute phase. Current data suggests that at least 10% of people with previously documented infection may develop PACS, and up to 50-80% of prevalence is reported among survivors after hospital discharge. This viewpoint will discuss various aspects of PACS, particularly in older adults, with a specific hypothesis to describe PACS as the expression of a modified aging trajectory induced by SARS CoV-2. This hypothesis will be argued from biological, clinical and public health view, addressing three main questions: (i) does SARS-CoV-2-induced alterations in aging trajectories play a role in PACS?; (ii) do people with PACS face immuno-metabolic derangements that lead to increased susceptibility to age-related diseases?; (iii) is it possible to restore the healthy aging trajectory followed by the individual before pre-COVID?. A particular focus will be given to the well-being of people with PACS that could be assessed by the intrinsic capacity model and support the definition of the healthy aging trajectory.

Association of COVID-19 with hepatic metabolic dysfunction

The coronavirus disease 2019 (COVID-19) pandemic continues to be a global problem with over 438 million cases reported so far. Although it mostly affects the respiratory system, the involvement of extrapulmonary organs, including the liver, is not uncommon. Since the beginning of the pandemic, metabolic com-orbidities, such as obesity, diabetes, hypertension, and dyslipidemia, have been identified as poor prognostic indicators. Subsequent metabolic and lipidomic studies have identified several metabolic dysfunctions in patients with COVID-19. The metabolic alterations appear to be linked to the course of the disease and inflammatory reaction in the body. The liver is an important organ with high metabolic activity, and a significant proportion of COVID-19 patients have metabolic comorbidities; thus, this factor could play a key role in orchestrating systemic metabolic changes during infection. Evidence suggests that metabolic dysregulation in COVID-19 has both short- and long-term metabolic implications. Furthermore, COVID-19 has adverse associations with metabolic-associated fatty liver disease. Due to the ensuing effects on the renin-angiotensin-aldosterone system and ammonia metabolism, COVID-19 can have significant implications in patients with advanced chronic liver disease. A thorough understanding of COVID-19-associated metabolic dysfunction could lead to the identification of important plasma biomarkers and novel treatment targets. In this review, we discuss the current understanding of metabolic dysfunction in COVID-19, focusing on the liver and exploring the underlying mechanistic pathogenesis and clinical implications.

Effect of cofactors on NAFLD/NASH and MAFLD. A paradigm illustrating the pathomechanics of organ dysfunction

Primary nonalcoholic fatty liver disease (NAFLD) is bi-directionally associated with the metabolic syndrome and its constitutive features ("factors": impaired glucose disposal, visceral obesity, arterial hypertension, and dyslipidemia). Secondary NAFLD occurs due to endocrinologic disturbances or other cofactors. This nosography tends to be outdated by the novel definition of metabolic associated fatty liver disease (MAFLD). Irrespective of nomenclature, this condition exhibits a remarkable pathogenic heterogeneity with unpredictable clinical outcomes which are heavily influenced by liver histology changes. Genetics and epigenetics, lifestyle habits [including diet and physical (in)activity] and immunity/infection appear to be major cofactors that modulate NAFLD/MAFLD outcomes, including organ dysfunction owing to liver cirrhosis and hepatocellular carcinoma, type 2 diabetes, chronic kidney disease, heart failure, and sarcopenia. The identification of cofactors for organ dysfunction that may help understand disease heterogeneity and reliably support inherently personalized medicine approaches is a research priority, thus paving the way for innovative treatment strategies.

COVID-19 Pandemic: Insights into Interactions between SARS-CoV-2 Infection and MAFLD

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become an ongoing global health pandemic. Since 2019, the pandemic continues to cast a long shadow on all aspects of our lives, bringing huge health and economic burdens to all societies. With our in-depth understanding of COVID-19, from the initial respiratory tract to the later gastrointestinal tract and cardiovascular systems, the multiorgan involvement of this infectious disease has been discovered. Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly named nonalcoholic fatty liver disease (NAFLD), is a major health issue closely related to metabolic dysfunctions, affecting a quarter of the world's adult population. The association of COVID-19 with MAFLD has received increasing attention, as MAFLD is a potential risk factor for SARS-CoV-2 infection and severe COVID-19 symptoms. In this review, we provide an update on the interactions between COVID-19 and MAFLD and its underlying mechanisms.