Renal interactions in liver dysfunction and failure

Early changes in laboratory tests predict liver function damage in patients with moderate coronavirus disease 2019: a retrospective multicenter study

Background

Most patients with coronavirus disease 2019 demonstrate liver function damage. In this study, the laboratory test data of patients with moderate coronavirus disease 2019 were used to establish and evaluate an early prediction model to assess the risk of liver function damage.

Methods

Clinical data and the first laboratory examination results of 101 patients with moderate coronavirus disease 2019 were collected from four hospitals’ electronic medical record systems in Jilin Province, China. Data were randomly divided into training and validation sets. A logistic regression analysis was used to determine the independent factors related to liver function damage in patients in the training set to establish a prediction model. Model discrimination, calibration, and clinical usefulness were evaluated in the training and validation sets.

Results

The logistic regression analysis showed that plateletcrit, retinol-binding protein, and carbon dioxide combining power could predict liver function damage (P < 0.05 for all). The receiver operating characteristic curve showed high model discrimination (training set area under the curve: 0.899, validation set area under the curve: 0.800; P < 0.05). The calibration curve showed a good fit (training set: P = 0.59, validation set: P = 0.19; P > 0.05). A decision curve analysis confirmed the clinical usefulness of this model.

Conclusions

In this study, the combined model assesses liver function damage in patients with moderate coronavirus disease 2019 performed well. Thus, it may be helpful as a reference for clinical differentiation of liver function damage.

Trial registration retrospectively registered.

Association of FIB-4 index and clinical outcomes in critically ill patients with acute kidney injury: a cohort study

Background

The relationship between fibrosis-4 (FIB-4) index and clinical outcomes in patients with acute kidney injury (AKI) is unclear. We aimed to investigate the association between FIB-4 index and all-cause mortality in critically ill patients with AKI.

Methods

We used data from the Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC-III) database (v1.4). The FIB-4 score was calculated using the existing formulas. logistic regression model, and Cox proportional hazards model were used to assessed the relationship between the FIB-4 index and in-hospital,28-day and 90-day mortality, respectively.

Results

A total of 3592 patients with AKI included in the data analysis. 395 (10.99%) patients died during hospitalization and 458 (12.74%) patients died in 28-day. During the 90-day follow-up, 893 (22.54%) patients were dead. An elevated FIB-4 value was significantly associated with increased in-hospital mortality when used as a continuous variable (odds ratio [OR] 1.183, 95% confidence interval [CI] 1.072–1.305, P = 0.002) and as a quartile variable (OR of Q2 to Q4 1.216–1.744, with Q1 as reference). FIB-4 was positively associated with 28-day mortality of AKI patients with hazard ratio (HR) of 1.097 (95% CI 1.008, 1.194) and 1.098 (95% 1.032, 1.167) for 90-day mortality, respectively.

Conclusion

This study demonstrated the FIB-4 index is associated with clinical outcomes in critically ill patients with acute kidney injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02071-2.

Kidney-liver pathophysiological crosstalk: its characteristics and importance

The kidney plays a crucial role in controlling the blood volume and pressure, electrolyte and acid-base balance, erythropoietin secretion, as well as renin-angiotensin-aldosterone system activity. All these renal activities have important repercussion in the organism, explaining why morbidity and mortality rates are high in patients with significant renal dysfunction. In this sense, there are renal-induced liver damages in acute kidney injury, as well as liver-induced renal damages in hepatic disease. Ischemia, reperfusion, cytokine outflow, pro-inflammatory cascades, metabolic acidosis, oxidative stress, and changes in enzymatic and metabolic pathways provide the bases for this bidirectional kidney-liver damage. In conclusion, knowing the characteristics of this kidney-liver crosstalk is crucial for handling the complications induced by this vicious circle.

Acute Kidney Injury Pharmacokinetic Changes and Its Impact on Drug Prescription

Acute kidney injury (AKI) is a common problem in hospitalized patients that is associated with significant morbid-mortality. The impact of kidney disease on the excretion of drugs eliminated by glomerular filtration and tubular secretion is well established, as well as the requirement for drug dosage adjustment in impaired kidney function patients. However, since impaired kidney function is associated with decreased activity of several hepatic and gastrointestinal drug-metabolizing enzymes and transporters, drugs doses adjustment only based on kidney alteration could be insufficient in AKI. In addition, there are significant pharmacokinetics changes in protein binding, serum amino acid levels, liver, kidney, and intestinal metabolism in AKI, thus the determination of plasma drug concentrations is a very useful tool for monitoring and dose adjustment in AKI patients. In conclusion, there are many pharmacokinetics changes that should be taken into account in order to perform appropriate drug prescriptions in AKI patients.

Metabolic syndrome and the hepatorenal reflex

Insufficient hepatic O₂ in animal and human studies has been shown to elicit a hepatorenal reflex in response to increased hepatic adenosine, resulting in the stimulation of renal as well as muscle sympathetic nerve activity and activating the renin angiotensin system. Low hepatic ATP, hyperuricemia, and hepatic lipid accumulation reported in metabolic syndrome (MetS) patients may reflect insufficient hepatic O₂ delivery, potentially accounting for the sympathetic overdrive associated with MetS. This theoretical concept is supported by experimental results in animals fed a high fructose diet to induce MetS. Hepatic fructose metabolism rapidly consumes ATP resulting in increased adenosine production and hyperuricemia as well as elevated renin release and sympathetic activity. This review makes the case for the hepatorenal reflex causing sympathetic overdrive and metabolic syndrome in response to exaggerated splanchnic oxygen consumption from excessive eating. This is strongly reinforced by the fact that MetS is cured in a matter of days in a significant percentage of patients by diet, bariatric surgery, or endoluminal sleeve, all of which would decrease splanchnic oxygen demand by limiting nutrient contact with the mucosa and reducing the nutrient load due to loss of appetite or dietary restriction.

Metabolic syndrome and the hepatorenal reflex

Insufficient hepatic O₂ in animal and human studies has been shown to elicit a hepatorenal reflex in response to increased hepatic adenosine, resulting in stimulation of renal as well as muscle sympathetic nerve activity and activating the renin angiotensin system. Low hepatic ATP, hyperuricemia, and hepatic lipid accumulation reported in metabolic syndrome (MetS) patients may reflect insufficient hepatic O₂ delivery, potentially accounting for the sympathetic overdrive associated with MetS. This theoretical concept is supported by experimental results in animals fed a high fructose diet to induce MetS. Hepatic fructose metabolism rapidly consumes ATP resulting in increased adenosine production and hyperuricemia as well as elevated renin release and sympathetic activity. This review makes the case for the hepatorenal reflex causing sympathetic overdrive and metabolic syndrome in response to exaggerated splanchnic oxygen consumption from excessive eating. This is strongly reinforced by the fact that MetS is cured in a matter of days in a significant percentage of patients by diet, bariatric surgery, or endoluminal sleeve, all of which would decrease splanchnic oxygen demand by limiting nutrient contact with the mucosa and reducing the nutrient load due to the loss of appetite or dietary restriction.

An update of the role of renin angiotensin in cardiovascular homeostasis

The renin angiotensin system (RAS) is thought to be the body's main vasoconstrictor system, with physiological effects mediated via the interaction of angiotensin II with angiotensin I receptors (the "classic" RAS model). However, since the discovery of the heptapeptide angiotensin 1-7 and the development of the concept of the "alternate" RAS system, with its ability to reduce arterial blood pressure, our understanding of this physiologic system has changed dramatically. In this review, we focus on the newly discovered functions of the RAS, particularly the potential clinical significance of these developments, especially in the realm of new pharmacologic interventions for treating cardiovascular disease.

Comprehensive review of post-liver resection surgical complications and a new universal classification and grading system

Liver resection is the gold standard treatment for certain liver tumors such as hepatocellular carcinoma and metastatic liver tumors. Some patients with such tumors already have reduced liver function due to chronic hepatitis, liver cirrhosis, or chemotherapy-associated steatohepatitis before surgery. Therefore, complications due to poor liver function are inevitable after liver resection. Although the mortality rate of liver resection has been reduced to a few percent in recent case series, its overall morbidity rate is reported to range from 4.1% to 47.7%. The large degree of variation in the post-liver resection morbidity rates reported in previous studies might be due to the lack of consensus regarding the definitions and classification of post-liver resection complications. The Clavien-Dindo (CD) classification of post-operative complications is widely accepted internationally. However, it is hard to apply to some major post-liver resection complications because the consensus definitions and grading systems for post-hepatectomy liver failure and bile leakage established by the International Study Group of Liver Surgery are incompatible with the CD classification. Therefore, a unified classification of post-liver resection complications has to be established to allow comparisons between academic reports.

Kidney injury in cirrhosis: pathophysiological and therapeutic aspects of hepatorenal syndromes

Acute kidney injury (AKI) is frequent in patients with cirrhosis. AKI and hyponatraemia are major determinants of the poor prognosis in advanced cirrhosis. The hepatorenal syndrome (HRS) denotes a functional and potential reversible impairment of renal function. Type 1 HRS, a special type of AKI, is a rapidly progressive AKI, whereas the renal function in type 2 HRS decreases more slowly. HRS is precipitated by factors such as sepsis that aggravate the effective hypovolaemia in decompensated cirrhosis, by lowering arterial pressure and cardiac output and enhanced sympathetic nervous activity. Therefore, attempts to prevent and treat HRS should seek to improve liver function and to ameliorate arterial hypotension, central hypovolaemia and cardiac output, and to reduce renal vasoconstriction. Ample treatment of HRS is important to prevent further progression and death, but as medical treatment only modestly improves long-term survival, these patients should always be considered for liver transplantation. Hyponatraemia, defined as serum sodium <130 mmol/L, is common in patients with decompensated cirrhosis. From a pathophysiological point of view, hyponatraemia is related to an impairment of renal solute-free water excretion most likely caused by an increased vasopressin secretion. Patients with cirrhosis mainly develop hypervolaemic hyponatraemia. Current evidence does not support routine use of vaptans in the management of hyponatraemia in cirrhosis.

Renal dysfunction in end-stage liver disease and post-liver transplant

Renal dysfunction is a frequent complication in patients with end-stage liver disease awaiting orthotopic liver transplantation and in the post-liver transplant period. Although the stereotypical form of renal dysfunction is the hepatorenal syndrome, other causes of acute kidney injury in this population include prerenal azotemia and acute tubular necrosis. Renal injury in a patient with cirrhosis is associated with a poor prognosis.