Epidemiology, Pathophysiology, and Clinical Perspectives of Intradialytic Hypertension.

BACKGROUND: Individuals with end-stage renal disease on chronic hemodialysis (HD) may encounter numerous HD-associated complications, including intradialytic hypertension (IDHYPER). Although blood pressure (BP) follows a predictable course in the post-HD period, BP levels during the session may vary across the individuals. Typically, a decline in BP is noted during HD, but a significant proportion of patients exhibit a paradoxical elevation. SUMMARY: Several studies have been conducted to understand the complexity of IDHYPER, but much remains to be elucidated in the future. This review article aimed to present the current evidence regarding the proposed definitions, the pathophysiologic background, the extent and clinical implications of IDHYPER, as well as the possible therapeutic options that have emerged from clinical studies. KEY MESSAGES: IDHYPER is noted in approximately 15% of individuals undergoing HD. Several definitions have been proposed, with a systolic BP rise >10 mm Hg from pre- to post-dialysis in the hypertensive range in at least four out of six consecutive HD treatments being suggested by the latest Kidney Disease: Improving Global Outcomes. Concerning its pathophysiology, extracellular fluid overload is a crucial determinant, with endothelial dysfunction, sympathetic nervous system overdrive, renin-angiotensin-aldosterone system activation, and electrolyte alterations being important contributors. Although its association with ambulatory BP in the interdialytic period is controversial, IDHYPER is associated with adverse cardiovascular events and mortality. Moving to its management, the antihypertensive drugs of choice should ideally be nondialyzable with proven cardiovascular and mortality benefits. Finally, rigorous clinical and objective assessment of extracellular fluid volume is essential. Volume-overloaded patients should be instructed about the importance of sodium restriction, while physicians ought to alter HD settings toward a greater dry weight reduction. The use of a low-sodium dialysate and isothermic HD could also be considered on a case-by-case basis since no randomized evidence is currently available.

The Role of Melatonin in Chronic Kidney Disease and Its Associated Risk Factors: A New Tool in Our Arsenal?

BACKGROUND: The increasing incidence of chronic kidney disease (CKD), as a consequence of the high prevalence of arterial hypertension and type 2 diabetes mellitus (T2DM), warrants the need for developing effective treatment approaches. In this regard, the pineal gland-derived hormone melatonin may represent an appealing treatment approach of CKD and its associated risk factors. SUMMARY: Targeting the adverse pathophysiology surrounding CKD and its associated risk factors has been the concept of pharmacologic treatment developed for its management. This review article aimed to present the role of melatonin in this direction, by providing an overview of melatonin's physiology followed by its effect as a therapeutic agent in arterial hypertension and T2DM. KEY MESSAGES: Melatonin, the primary darkness hormone, possesses pleiotropic mechanisms of action which may have important implications in various pathologic states since its receptors are situated across various organ systems. As a treatment tool in arterial hypertension, melatonin may be efficacious in reducing both daytime and nocturnal blood pressure by influencing endothelial function, oxidative stress, the autonomic nervous system, and the renin-angiotensin system. Melatonin may also increase insulin sensitivity and ß-cell function. However, late meal intake may be detrimental in glucose regulation, as consumption close to melatonin peak concentrations may induce hyperglycemia and insulin resistance. This finding may explain the inconsistent glycose regulation achieved with melatonin in clinical trials and meta-analyses. Additionally, the presence of genetic variants to melatonin receptor 2 may predispose to T2DM development. Finally, we present the available preclinical evidence supporting melatonin's efficacy in ameliorating CKD's pathophysiology since melatonin supplementation has not been adequately explored in patients with CKD. The combined use of stem cells with melatonin is an appealing therapeutic approach which ought to be assessed further.

Overview of infections as an etiologic factor and complication in patients with vasculitides.

Vasculitides, a form of inflammatory autoimmune disease targeting the vessels, constitute an entity with significant morbidity and mortality. Infections have long been associated with vasculitides as a result of the incident immunosuppression following treatment induction and maintenance. Several microbial pathogens have been described as etiologic factors of infections in this patient population according to the type of vessels affected. Intense research has also been recently conducted in the interplay between vasculitides and certain viral infections, namely human immunodeficiency virus and severe acute respiratory syndrome coronavirus 2. Of note, a plethora of scientific evidence is available regarding the role of infections as triggering factors for vasculitides. Among the main mechanisms implicated in this direction are the activation of B and T cells, the direct endothelial insult, the immune complex-mediated vascular injury, and the cell-mediated, type IV hypersensitivity vessel damage. Therefore, this review aims to summarize all the available evidence concerning this bidirectional interplay between infections and vasculitides.

Dyslipidemia in Chronic Kidney Disease: Contemporary Concepts and Future Therapeutic Perspectives.

BACKGROUND: Chronic kidney disease (CKD) is an increasingly prevalent disease state met with great morbidity and mortality primarily resulting from the high incidence of adverse cardiovascular outcomes. Therapeutic strategies in this patient population aim at controlling modifiable cardiovascular risk factors, including dyslipidemia. SUMMARY: In this review article, we first provide the latest pathophysiologic evidence regarding the altered dyslipidemia pattern in CKD, followed by its contemporary management according to the latest guidelines. Moreover, we present the current progress regarding the emerging therapeutic strategies. Key Messages: The presence of renal impairment leads to alterations in cholesterol structure, metabolism, and reverse transport paired with increased oxidative stress. Statins remain the cornerstone of dyslipidemia management in patients with kidney dysfunction who are at risk for cardiovascular events. However, their efficacy is debatable in end-stage renal disease under renal replacement therapy. Therefore, novel treatment approaches aiming at hypertriglyceridemia, proprotein convertase subtilisin/kexin type 9, and lipoprotein(a) are under rigorous investigation while the research of gut microbiome might provide additional mechanistic and therapeutic insight.

Opportunistic screening for hypertension in the general population in Greece: International Society of Hypertension May Measurement Month 2019.

Hypertension remains a major public health issue with inadequate control worldwide. The May Measurement Month (MMM) initiative by the International Society of Hypertension was implemented in Greece in 2019 aiming to raise hypertension awareness and control. Adult volunteers (≥18 years) were recruited through opportunistic screening in five urban areas. Information on medical history and triplicate sitting blood pressure (BP) measurements were obtained using validated automated upper-arm devices. Hypertension was defined as systolic BP ≥140 mmHg and/or diastolic ≥90 mmHg, and/or self-reported use of drugs for hypertension. A total of 5727 were analysed [mean age 52.7 (SD 16.6) years, men 46.5%, 88.3% had BP measurement in the last 18 months]. The prevalence of hypertension was (41.6%) and was higher in men and in older individuals. Among individuals with hypertension, 78.7% were diagnosed, 73.1% treated, and 48.3% controlled. Awareness, treatment, and control of hypertension were higher in women and in older individuals. Hypertensives had a higher body mass index (BMI) and were more likely to have diabetes, myocardial infarction and stroke, and less likely to smoke than normotensives (all P < 0.001). Among treated hypertensives, 65.1% were on monotherapy, and with increasing number of antihypertensive drugs the BP levels were higher and hypertension control rates lower. The prevalence of hypertension in Greece is high, with considerable potential for improving awareness, treatment, and control. Screening programmes, such as MMM, need to be widely implemented at the population level, together with training programmes for healthcare professionals aiming to optimise management and control.

Treatment of Hypertension in Chronic Kidney Disease.

PURPOSE OF REVIEW: Chronic kidney disease (CKD) is recognized as a worldwide epidemic. Hypertension commonly coexists with CKD and its prevalence is progressively increasing as kidney function declines. RECENT FINDINGS: For patients with established CKD and/or diabetes with albuminuria, the updated hypertension guidelines have recommended a blood pressure (BP) goal < 130/80 mmHg. Blood pressure level above 130/80 mmHg in CKD patients requires lifestyle modifications and multiple antihypertensive medications. According to recent guidelines, angiotensin-converting enzyme (ACE) inhibitors should be the drugs of first choice. Angiotensin II receptor blockers (ARBs) should be used if the ACE inhibitor is not tolerated. Non-dihydropyridine CCBs consistently reduce albuminuria and slow the decline in kidney function. Dihydropyridine CCBs should not be used as monotherapy in proteinuric CKD patients but always in combination with a RAAS blocker. Diuretics are commonly used and represent the cornerstone in the management of CKD patients. All the other agents are used when treatment with the other primary agents have failed. In patients with CKD, an intensive BP goal < 130/80 mmHg has been recommended. We review current treatment options.

An unusual case of acute kidney injury - idiopathic granulomatous tubulointerstitial nephritis.

We present a case which emphasizes the importance of performing a kidney biopsy in each case of acute kidney injury (AKI) of unknown etiology. The unexpected histological diagnosis of granulomatous interstitial nephritis (GIN) is a rare cause of AKI. The main causes of GIN include drugs (NSAIDs, antibiotics), sarcoidosis, and infections (mycobacterial and fungal). In our case, a 68-year-old woman was admitted with AKI, absence of symptoms and unremarkable history, apart from coronary heart disease. Renal biopsy was performed, since history as well as clinical and laboratory data could not define a cause of AKI. A more meticulous clinical and laboratory investigation followed the histological diagnosis in order to rule out sarcoidosis, vasculitis or any other known causes of GIN. Finally the diagnosis was characterized as AKI due to idiopathic GIN. The patient responded well to corticosteroids.

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention.

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Cardiorenal syndrome and iron supplementation-more benefits than risks: a narrative review.

Intravenous iron administration has emerged as a crucial intervention for managing patients with cardiorenal syndrome (CRS) and iron deficiency, with or without the presence of anemia. Multiple studies have demonstrated the benefits of intravenous iron supplementation in improving anemia, symptoms, and functional capacity in patients with HF and iron deficiency. Furthermore, iron supplementation has been associated with a reduction in hospitalizations for HF exacerbation and the improvement of patients' quality of life and clinical outcomes. In addition to its effects on HF management, emerging evidence suggests a potential positive impact on kidney function in patients with CRS. Studies have shown an increase in estimated glomerular filtration rate and improvements in renal function markers in patients receiving intravenous iron therapy, highlighting the potential of this intervention in patients with CRS. This paper reviews the existing literature on the impact of intravenous iron therapy in these patient populations and explores its effects on various clinical outcomes. Future research endeavors are eagerly awaited to further improve our understanding of its clinical implications and optimize patient outcomes.

The Role of Hypertension in Cognitive Dysfunction.

Cognitive impairment and subsequent dementia are considered significant health challenges. In patients with established dementia, it is argued that hypertension is the main risk factor for small vessel ischemic disease and additional cortical white matter lesions. Cognitive domains and impairments associated with hypertension include learning, memory, attention, abstract reasoning, mental flexibility, psychomotor skills, and executive function. It is uncontrolled hypertension in midlife-but not late life-that is associated with worse cognitive impairment. Advanced imaging techniques confirm the effect of uncontrolled hypertension in developing dementia. Functional changes in the arterial system and an increase in arterial stiffness could be involved in the onset of dementia. In most studies, it is argued that better blood pressure control and duration of antihypertensive medication are associated with the incidence of dementia. In this review, the available data on the relationship between cognitive dysfunction and hypertension are examined.

Pilot study on the effect of flavonoids on arterial stiffness and oxidative stress in chronic kidney disease.

BACKGROUND: Flavonoids, the main class of polyphenols, exhibit antioxidant and antihypertensive properties. AIM: To prospectively investigate the impact of flavonoids on arterial stiffness in patients with chronic kidney disease (CKD) stages I-IV. METHODS: In this prospective, single-arm study, CKD patients with arterial hypertension and diabetes mellitus were enrolled. Baseline demographic, clinical, and laboratory variables were recorded. Patients received daily treatment with a phenol-rich dietary supplement for 3 months. Blood pressure, arterial stiffness (carotid-femoral pulse wave velocity, central pulse pressure), and oxidative stress markers (protein carbonyls, total phenolic compound, total antioxidant capacity) were measured at baseline and at study end. RESULTS: Sixteen patients (mean age: 62.5 years, 87.5% male) completed the study. Following intervention, peripheral systolic blood pressure decreased significantly by 14 mmHg (P < 0.001). Carotid-femoral pulse wave velocity decreased from 8.9 m/s (baseline) to 8.2 m/s (study end) (P < 0.001), and central pulse pressure improved from 59 mmHg to 48 mmHg (P = 0.003). Flavonoids also reduced oxidative stress markers including protein carbonyls (P < 0.001), total phenolic compound (P = 0.001), and total antioxidant capacity (P = 0.013). CONCLUSION: Flavonoid supplementation in CKD patients shows promise in improving blood pressure, arterial stiffness, and oxidative stress markers.

Prevalence, awareness, and control of hypertension in Greece before and after the COVID-19 pandemic: May Measurement Month survey 2019-2022.

OBJECTIVE: The COVID-19 pandemic had an adverse impact on several cardiovascular risk factors. This study investigated the prevalence, awareness and treatment of hypertension in Greece before and after the pandemic. Data were collected in the context of the May Measurement Month (MMM) global survey initiated by the International Society of Hypertension. METHODS: Adult volunteers (age ≥ 18 years) were recruited through opportunistic screening in public areas across cities in Greece in 2019 and 2022. Medical history and triplicate sitting blood pressure (BP) measurements were taken using validated automated upper-arm cuff devices. The data were uploaded to the international MMM cloud platform. Hypertension was defined as systolic BP ≥ 140 mm Hg and/or diastolic ≥90 mm Hg and/or self-reported use of drugs for hypertension. The same threshold was used to define uncontrolled BP in treated individuals. RESULTS: Data from 12,080 adults were collected (5,727/6,353 in MMM 2019/2022; men 46/49%, p < 0.01; mean age 52.7 ± 16.6/54.8 ± 16.2, p < 0.001; smokers, 24.7/30.5, p < 0.001; diabetics 12/11.5%, p = NS; cardiovascular disease 5/5.8%, p = NS). The prevalence of hypertension was 41.6/42.6% (MMM 2019/2022, p = NS), with 21.3/27.5% of individuals with hypertension being unaware of their condition (p < 0.001), 5.6/2.4% aware untreated (p < 0.001), 24.8/22.1% treated uncontrolled (p < 0.05), and 48.3/47.8% treated controlled (p = NS). CONCLUSION: In Greece, the COVID-19 pandemic did not appear to affect the prevalence and control of hypertension; however, the rate of undiagnosed hypertension was higher after the pandemic. National strategies need to be implemented for the early detection and optimal management of hypertension in the general population in Greece.

Novel therapeutic approaches in the management of chronic kidney disease: a narrative review.

Chronic kidney disease (CKD) remains a pathologic entity with constantly rising incidence and high rates of morbidity and mortality, which are associated with serious cardiovascular complications. Moreover, the incidence of end-stage renal disease tends to increase. The epidemiological trends of CKD warrant the development of novel therapeutic approaches aiming to prevent its development or retard its progression through the control of major risk factors: type 2 diabetes mellitus, arterial hypertension, and dyslipidemia. Contemporary therapeutics such as sodium-glucose cotransporter-2 inhibitors and second-generation mineralocorticoid receptor antagonists are utilized in this direction. Additionally, experimental and clinical studies present novel drug categories that could be employed in managing CKD, such as aldosterone synthesis inhibitors or activators guanylate cyclase, while the role of melatonin should be further tested in the clinical setting. Finally, in this patient population, the use of hypolipidemic agents may provide incremental benefits.

Metabolic Dysfunction-Associated Fatty Liver Disease in Newly Diagnosed, Treatment-Naive Hypertensive Patients and Its Association with Cardiorenal Risk Markers.

INTRODUCTION: Patients with arterial hypertension frequently present with comorbidities that are associated with increased cardiorenal risk, such as metabolic dysfunction-associated fatty liver disease (MAFLD). AIMS: Our study aimed to assess the prevalence and the association of MAFLD with cardiorenal risk markers in newly diagnosed, treatment-naïve hypertensive patients. METHODS: We recruited 281 individuals with new-onset hypertension who were not prescribed any medication. Medical history, clinical examination findings, and laboratory test results were recorded. Liver steatosis was assessed through fatty liver index (FLI) calculation. Patients with FLI ≥ 60 together with one main metabolic abnormality (type 2 diabetes mellitus or overweight/obesity) or at least two metabolic risk abnormalities (increased waist circumference, blood pressure, plasma triglycerides, presence of prediabetes or insulin resistance, decreased plasma high-density lipoprotein) fulfilled the diagnostic criteria for MAFLD. RESULTS: The prevalence of MAFLD in our study population was 28.7%. Individuals with MAFLD were more frequently male and had increased body mass index. Systolic, diastolic, and pulse pressure values were significantly higher in this group of patients. Moreover, lipid, renal, glucose, and inflammatory markers were considerably deranged in patients with MAFLD. After multivariate regression analysis, uric acid, ferritin, and apoE emerged as independent predictors of MAFLD. Area under receiver operating characteristics curve revealed that uric acid had the greatest diagnostic accuracy, with the ideal cutoff being ≥ 5.2 mg/dl (sensitivity: 77.6%, specificity: 76.3%). CONCLUSION: MAFLD represents a common comorbidity in hypertensive patients and is associated with markers of cardiorenal risk. Uric acid may be indicative of MAFLD in particular.

Prognostic Significance of Risk Factors and Biomarkers in Patients Hospitalized for Cardiorenal Syndromes: A Pilot Study.

BACKGROUND: Cardiorenal syndromes (CRS), involving the heart-kidney cross-talk and the activation of neurohumoral and inflammatory pathways, are an entity characterized by high morbidity and mortality. OBJECTIVE: To evaluate the prognostic role of risk factors and biomarkers in patients hospitalized for CRS. METHODS: In this observational cohort study, 100 consecutive patients hospitalized for CRS were enrolled. Socio-demographic characteristics, personal medical history, and prior medication use were recorded upon admission, and echocardiography was performed. Moreover, an array of blood markers were measured. The endpoint of interest was a composite of death or dialysis dependence at discharge. RESULTS: Patients were classified into two groups; Group 1 (N= 52): discharged being dialysis-independent, Group 2 (N=48): death/dialysis dependence at discharge. No significant differences were detected in baseline characteristics between the two groups. Group 2 patients used renin-angiotensin-aldosterone system blockers (RAASb) less often and more frequently presented with oliguria/anuria. Group 2 patients had significantly lower hemoglobin, serum albumin, and 25-hydroxy-vitamin D (25(OH)D). At the same time, serum phosphate, potassium, and parathyroid hormone (PTH) were significantly higher in Group 2 patients. In a multivariate regression analysis, lack of prior RAASb and lower 25(OH)D levels were independently associated with an increased risk of death or dialysis dependence at discharge. 25(OH)D/PTH ratio was the most accurate predictor of the composite endpoint (Sensitivity: 79.4%, Specificity: 70.4%). CONCLUSION: Lack of prior RAASb use, high PTH, low 25(OH)D levels, and low 25(OH) D/PTH ratio are associated with a poor prognosis in patients hospitalized for CRS.

Endothelial Dysfunction in Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis.

Individuals with nonalcoholic fatty liver disease (NAFLD) are characterized by increased cardiovascular risk. Endothelial dysfunction, a mechanism implicated in those processes, may constitute the missing link in this interaction. Therefore, this systematic review and meta-analysis aims to evaluate the association of endothelial dysfunction, assessed by flow-mediated dilation (FMD) of the brachial artery, with NAFLD. We conducted a systematic literature search for studies assessing the difference in FMD between patients with NAFLD and controls. Exclusion criteria consisted of preclinical studies, studies in children/adolescents, no FMD assessment, and the absence of an NAFLD/control group. The database search identified 96 studies. Following the application of the exclusion criteria, 22 studies were included in the meta-analysis (NAFLD: 2164 subjects; control: 3322 subjects). Compared with controls, patients with NAFLD had significantly lower FMD% values (SMD: −1.37, 95% CI −1.91 to −0.83, p < 0.001, I2: 98%). Results remained unaffected after exclusion of any single study. Subgroup analysis revealed significantly decreased FMD in NAFLD subjects diagnosed with liver ultrasound or liver biopsy compared with method combination or other methods, while no differences were observed according to the chosen cuff inflation threshold, the presence of a significant difference in obesity measures between the groups, or the type of the control group (age- and sex-matched vs. other). Funnel plot asymmetry was not observed. Finally, compared with patients with pure steatosis, individuals with nonalcoholic steatohepatitis had significantly lower FMD (SMD: −0.81, 95% CI −1.51 to −0.31, p = 0.003, I2: 81%). In conclusion, FMD of the brachial artery, indicative of endothelial dysfunction, was significantly reduced in subjects with nonalcoholic fatty liver disease. Patients with nonalcoholic steatohepatitis might be facing a more pronounced endothelial impairment.

Metabolic Dysfunction-Associated Fatty Liver Disease in the National Health and Nutrition Examination Survey 2017-2020: Epidemiology, Clinical Correlates, and the Role of Diagnostic Scores.

The recent establishment of metabolic dysfunction-associated fatty liver disease (MAFLD) has led to a reevaluation of its epidemiology, diagnosis, and clinical implications. In this study, we aimed to evaluate MAFLD's epidemiology and its association with other pathologic states and biomarkers, as well as to assess the prevalence of the different fibrosis stages in the MAFLD population, together with the importance of diagnostic scores in the preliminary determination of significant fibrosis. After analyzing the National Health and Nutrition Examination Survey (NHANES) 2017-2020, we found a high prevalence of MAFLD, at 58.6% of the studied population. MAFLD was accompanied by numerous comorbidities, which were increasingly common in individuals with higher grades of liver fibrosis. Fatty liver index emerged as a reliable indicator of MAFLD, as well as significant fibrosis. The estimation of fatty liver index could be a reasonable addition to the evaluation of patients with metabolic risk factors and could lead a diagnosis in the absence of liver elastography or biopsy. Further studies are needed to enhance our knowledge regarding its prognosis, as well as the role of novel therapies in its prevention or regression.

Interplay between metabolic dysfunction-associated fatty liver disease and chronic kidney disease: Epidemiology, pathophysiologic mechanisms, and treatment considerations.

The recently proposed nomenclature change from non-alcoholic fatty liver disease to metabolic dysfunction-associated fatty liver disease (MAFLD) has resulted in the reappraisal of epidemiological trends and associations with other chronic diseases. In this context, MAFLD appears to be tightly linked to incident chronic kidney disease (CKD). This association may be attributed to multiple shared risk factors including type 2 diabetes mellitus, arterial hypertension, obesity, dyslipidemia, and insulin resistance. Moreover, similarities in their molecular pathophysiologic mechanisms can be detected, since inflammation, oxidative stress, fibrosis, and gut dysbiosis are highly prevalent in these pathologic states. At the same time, lines of evidence suggest a genetic predisposition to MAFLD due to gene polymorphisms, such as the PNPLA3 rs738409 G allele polymorphism, which may also propagate renal dysfunction. Concerning their management, available treatment considerations for obesity (bariatric surgery) and novel antidiabetic agents (glucagon-like peptide 1 receptor agonists, sodium-glucose co-transporter 2 inhibitors) appear beneficial in preclinical and clinical studies of MAFLD and CKD modeling. Moreover, alternative approaches such as melatonin supplementation, farnesoid X receptor agonists, and gut microbiota modulation may represent attractive options in the future. With a look to the future, additional adequately sized studies are required, focusing on preventing renal complications in patients with MAFLD and the appropriate management of individuals with concomitant MAFLD and CKD.

Trimethylamine N-Oxide Levels in Non-Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis.

Non-alcoholic fatty liver disease (NAFLD) represents an entity with an increasing prevalence which is characterized by significant hepatic and extrahepatic complications. Its pathophysiology is multifactorial, with gut dysbiosis being considered a major determinant. In this systematic review and meta-analysis, we tried to evaluate the association between the major gut microbial metabolite trimethylamine N-oxide (TMAO) and NAFLD. We performed a literature search for studies that determined circulating TMAO in patients with and without NAFLD. The database search identified 136 studies, and upon application of the exclusion criteria, 7 studies with 7583 individuals (NAFLD 2923, control 4660) were ultimately included in the meta-analysis. Compared to the control group, NAFLD patients had significantly higher circulating TMAO (SMD: 0.66, 95% CI -0.12 to 1.21, p = 0.02, I2: 94%). The results remained unaffected after the exclusion of one influential study. The subgroup analysis revealed significantly higher TMAO in individuals with histologically proven NAFLD and in studies measuring TMAO with high-performance liquid chromatography. No differences were observed according to the study design or study region. However, funnel plot asymmetry was observed, indicating publication bias. In conclusion, patients with NAFLD had increased levels of TMAO, a hazardous gut microbial metabolite, suggesting its important role in the gut-liver interaction.

COVID-19 and Kidney Disease: A Clinical Perspective.

Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome Coronavirus- 2 (SARS-CoV-2), has caused a global pandemic with high morbidity and mortality. The presence of several comorbidities has been associated with a worse prognosis, with chronic kidney disease being a critical risk factor. Regarding COVID-19 complications, other than classical pneumonia and thromboembolism, acute kidney injury (AKI) is highly prevalent and represents a poor prognostic indicator linked to increased disease severity and mortality. Its pathophysiology is multifactorial, revolving around inflammation, endothelial dysfunction, and activation of coagulation, while the direct viral insult of the kidney remains a matter of controversy. Indirectly, COVID-19 AKI may stem from sepsis, volume depletion, and administration of nephrotoxic agents, among others. Several markers have been proposed for the early detection of COVID-19 AKI, including blood and urinary inflammatory and kidney injury biomarkers, while urinary SARS-CoV-2 load may also be an early prognostic sign. Concerning renal replacement therapy (RRT), general principles apply to COVID-19 AKI, but sudden RRT surges may mandate adjustments in resources. Following an episode of COVID-19 AKI, there is a gradual recovery of kidney function, with pre-existing renal impairment and high serum creatinine at discharge being associated with kidney disease progression and long-term dialysis dependence. Finally, kidney transplant recipients represent a special patient category with increased susceptibility to COVID- 19 and subsequent high risk of severe disease progression. Rates of mortality, AKI, and graft rejection are significantly elevated in the presence of COVID-19, highlighting the need for prevention and careful management of the disease in this subgroup.