Cytokine production increases and cytokine clearance decreases in mice with bilateral nephrectomy

Blood markers for type-1, -2, and -3 inflammation are associated with severity of acutely decompensated cirrhosis

BACKGROUND & AIMS

In patients with acutely decompensated cirrhosis (ADC) who present with clinically apparent precipitants (i.e., infections, acute liver injury), alterations in blood markers of inflammation associate with progression toward severe phenotypes (e.g., acute-on-chronic liver failure [ACLF]). However, it is unclear whether alterations in blood inflammatory markers associate with progression of ADC independently of precipitants.

METHODS

We prospectively enrolled 394 patients admitted for ADC who were classified into four phenotypes of increasing severity: no organ dysfunction (n = 168), organ dysfunction alone (n = 72), organ failure without ACLF (n = 91), and ACLF (n = 63). Clinical blood cell counts and serum levels of inflammatory markers (including soluble markers related to type-1, type-2, and type-3 inflammation) were obtained at enrollment. Ordinal regression with adjacent categories logit model adjusted for confounders (including precipitants) was used to analyze associations between changes in each blood inflammatory marker and the worsening of ADC.

RESULTS

Inflammatory markers that were associated with a higher risk of progressing to the next more severe stage were as follows: increasing neutrophil counts (adjusted common odds ratio [cOR] 1.17, 95% CI 1.06-1.28); increasing levels of the type-2 cytokine interleukin (IL)-25 (cOR 1.21, 95% CI 1.06-1.39), type-3 cytokines IL-6 (cOR 1.15, 95% CI 1.02-1.28) and IL-22 (cOR 1.16, 95% CI 1.03-1.30), or anti-inflammatory soluble CD163 (cOR 1.94, 95% CI 1.58-2.38); decreasing lymphocyte counts (cOR 0.77, 95% CI 0.68-0.87); or decreasing levels of the type-1 cytokine IFN-γ (cOR 0.85, 95% CI 0.75-0.95).

CONCLUSIONS

Among patients with ADC, alterations in blood levels of cytokines related to type-1, type-2 and type-3 inflammation, together with neutrophilia, lymphopenia and elevated anti-inflammatory signals were individually associated with an increased risk of progressing toward ACLF, independently of the presence of clinically apparent precipitants.

IMPACT AND IMPLICATIONS

This study reveals that among patients with acutely decompensated cirrhosis, alterations in blood levels of cytokines related to type-1, type-2 and type-3 inflammation, together with neutrophilia, lymphopenia and elevated anti-inflammatory signals were individually associated with increased risk of progressing toward acute-on-chronic liver failure, independently of the presence of clinically apparent precipitants. These findings raise questions about the role of impaired barrier tissues and dysregulated production of blood immune cells in the pathophysiology of severe phenotypes of acutely decompensated cirrhosis, stimulating research to identify potential new biomarkers and targets for novel therapeutic approaches.

Procalcitonin levels in septic and nonseptic subjects with AKI and ESKD prior to and during continuous kidney replacement therapy (CKRT)

BACKGROUND

Procalcitonin is a 14.5 kDa protein used clinically as a marker of sepsis and therapeutic response to antibiotic therapy. However, its utility in critically ill patients with either acute kidney injury (AKI) or end-stage kidney disease (ESKD) who require continuous kidney replacement therapy (CKRT) is unknown. The aim of this study was to determine if plasma levels of procalcitonin could reliably distinguish septic from nonseptic status in patients with AKI or ESKD prior to or during CKRT.

METHODS

Procalcitonin concentrations were measured in plasma of 41 critically ill septic or non-septic subjects with AKI or ESKD prior to CKRT (pre-CKRT) and on days 1, 2, and 3 of CKRT in this retrospective cohort study (n = 111 total plasma measurements). Continuous venovenous hemodialysis was the modality of CKRT in these patients. Sepsis status was stringently defined based on culture results. Effluent procalcitonin levels were ascertained on days 1, 2, and 3 of CKRT to assess the clearance of procalcitonin and effects on plasma levels.

RESULTS

92% (66/72) of the plasma procalcitonin measurements among nonseptic patients with either AKI or ESKD were ≥ 0.5 ng/mL (the diagnostic threshold beyond which bacterial infection is very likely). Prior to CKRT initiation, procalcitonin levels were (median (IQR), ng/mL) 5.6 (1.5-18.9) in nonseptic AKI and 58.1 (6.9-195.5) in septic AKI (P = 0.03) and were 3.3 (1.2-8.3) in nonseptic ESKD and 3.7 (1.4-209.8) in septic ESKD (P = 0.79). However, despite being significantly elevated in septic patients with AKI, substantial overlap among procalcitonin levels was present and ROC curve analysis found no cut point that could reliably separate septic from nonseptic patients. Effluent procalcitonin levels were consistently ~ 20% of plasma levels throughout the course of CKRT (i.e., sieving coefficient was 0.2) suggesting that clearance occurs during therapy. However, plasma procalcitonin levels did not significantly decline during CKRT in either AKI or ESKD.

CONCLUSION

Procalcitonin levels are markedly elevated in nonseptic critically ill patients with either AKI or ESKD and do not effectively distinguish sepsis from nonseptic status prior to or during CKRT. We conclude that procalcitonin testing should be avoided in critically ill patients with kidney failure since results are nonspecific in this population.

Claudin-17 Deficiency Drives Vascular Permeability and Inflammation Causing Lung Injury

The role of claudin-17 (Cldn17), a tight-junction protein, in vascular permeability remains unclear. We investigated the impact of Cldn17 suppression on vascular permeability. The Miles assay demonstrated significantly increased vascular permeability in the lungs and skin of Cldn17-/- mice, as evidenced by elevated Evan's blue dye extravasation. The Matrigel plug assay demonstrated increased hemoglobin extravasation. Histopathological analysis revealed alveolar flooding, inflammatory cell infiltration, and lung injury in Cldn17-/- lungs. Wet/dry lung weight ratios indicated pulmonary edema, supporting the role of Cldn17 in pulmonary fluid balance, which was exacerbated with lipopolysaccharide administration. Ribosomal nucleic acid sequencing identified distinct transcriptional changes, with the principal component analysis showing clear clustering. Differential gene expression analysis highlighted significant alterations in inflammatory and metabolic pathways. Gene ontology and pathway enrichment analyses revealed the upregulation of immune-related processes, including leukocyte adhesion, interferon-gamma response, and neutrophil degranulation, alongside metabolic dysregulation affecting lipid transport and cytoskeletal organization. Reactome pathway analysis implicated Cldn17 in antigen presentation, interleukin-17 signaling, and inflammatory responses. These findings establish Cldn17 as a critical regulator of vascular permeability and immune homeostasis. Its deficiency drives vascular leakage, exacerbates lung injury, and alters immune signaling pathways, underscoring its potential as a therapeutic target for inflammatory lung diseases.

The association between anti-inflammatory therapies and renal outcomes in patients with established cardiovascular disease or high cardiovascular risks: a meta-analysis of randomised controlled trials

BACKGROUND

To assess the relationship between anti-inflammatory therapy and renal events risk in participants with cardiovascular risks or diagnosed cardiovascular disease (CVD).

METHODS

Literature searches were carried out in PubMed, Embase, clinicaltrial.gov and the Cochrane Central Register of Controlled Trials. Randomised controlled trials that were published from January 1995 to July 2024, compared anti-inflammatory therapy and placebo in participants at cardiovascular risks or with diagnosed CVD and with reports of renal outcomes were included. The results were shown as risk ratio (RR) and 95% confidence interval (CI).

RESULTS

In comparison to placebo, therapies targeting inflammation did not exhibit a significant association with the risk of composite renal outcomes (worsening of renal function, death due to kidney disease and end-stage renal disease) (RR = 0.89, 95% CI 0.40 to 1.99, I2 = 0%). The risk of worsening of renal function (RR = 0.81, 95% CI 0.21 to 3.07, I2 = NA), end-stage renal disease (RR = 0.94, 95% CI 0.31 to 2.85, I2 = 0%), death due to kidney disease (RR = 3.00, 95% CI 0.12 to 73.56, I2 = NA), chronic kidney disease (RR = 1.77, 95% CI 0.74 to 4.23, I2 = 0%), chronic renal failure (RR = 1.70, 95% CI 0.56 to 5.15, I2 = 61%) and acute kidney injury (RR = 1.16, 95% CI 0.95 to 1.42, I2 = 0%) showed no significant difference between patients receiving anti-inflammatory therapy and placebo.

CONCLUSION

Current evidence did not indicate associations between anti-inflammatory therapies and adverse renal events risks in patients with cardiovascular risks or established CVD. Future researches are needed to explore the renal effects of anti-inflammatory therapy.

Baicalin: a potential therapeutic agent for acute kidney injury and renal fibrosis

Acute kidney injury (AKI) is a common critical clinical disease that is linked to significant morbidity, recurrence, and mortality. It is characterized by a fast and prolonged loss in renal function arising from numerous etiologies and pathogenic pathways. Renal fibrosis, defined as the excessive accumulation of collagen and proliferation of fibroblasts within renal tissues, contributes to the structural damage and functional decline of the kidneys, playing a pivotal role in the advancement of Chronic Kidney Disease (CKD). Until now, while continuous renal replacement therapy (CRRT) has been utilized in the management of severe AKI, there remains a dearth of effective targeted therapies for AKI stemming from diverse etiologies. Similarly, the identification of specific biomarkers and pharmacological targets for the treatment of renal fibrosis remains a challenge. Baicalin, a naturally occurring compound classified within the flavonoid group and commonly found in the Chinese herb Scutellaria baicalensis, has shown a range of pharmacological characteristics, such as antioxidant, anti-inflammatory, antifibrotic, antitumor and antiviral effects, as evidenced by research studies. Research shows that Baicalin has potential in treating kidney diseases like AKI and renal fibrosis. This review aims to summarize Baicalin's progress in these areas, including its molecular mechanism, application in treatment, and absorption, distribution, metabolism, and excretion. Baicalin's therapeutic effects are achieved through various pathways, including antioxidant, anti-inflammatory, antifibrosis, and regulation of apoptosis and cell proliferation. Besides, we also hope this review may give some enlightenment for treating AKI and renal fibrosis in clinical practice.

Nomogram model for predicting secondary infection in critically ill patients with heatstroke: A pilot study from China

OBJECTIVE

In this retrospective analysis, we explored the clinical characteristics and risk factors of secondary infections in patients with severe heatstroke with the aim to gain epidemiological insights and identify risk factors for secondary infections.

METHOD

The study included 129 patients with severe heatstroke admitted to the General Hospital of the Southern Theater Command of the PLA between January 1, 2011, and December 31, 2021. Patients were divided into an infection group (n = 24) and a non-infection group (n = 105) based on infection occurrence within 48 h of intensive care unit (ICU) admission. Clinical indicators, infection indicators, and clinical outcomes within 24 h of ICU admission were collected and compared between the groups. Independent risk factors for infection in patients with severe heatstroke were analyzed using univariate and multivariate analyses. A nomogram model was constructed, evaluated, and validated.

RESULT

Among the 129 patients with heatstroke, 24 developed secondary infections. Infections occurred between days 3 and 10 post-ICU admission, primarily affecting the lungs. Multivariate analysis identified vasopressor use, serum creatinine level, and gastrointestinal dysfunction at admission as independent risk factors, while elevated lymphocyte count (odds ratio [OR] = 0.167; 95% confidence interval [CI] 0.049-0.572; P = 0.004) was protective against severe heatstroke. Infected patients required longer durations of mechanical ventilation (OR = 2.764; 95% CI, 1.735-4.405; P = 0.044) and total hospital stay than those in the non-infection group. The nomogram model demonstrated clinical feasibility.

CONCLUSION

Increased lymphocyte count is an independent protective factor against infections in patients with severe heatstroke. Vasopressor use, gastrointestinal dysfunction, and elevated serum creatinine levels are independent risk factors. These indicators can aid clinicians in assessing infection risk in patients with severe heatstroke.

Lymphocytes and innate immune cells in acute kidney injury and repair

Acute kidney injury (AKI) is a common and serious disease entity that affects native kidneys and allografts but for which no specific treatments exist. Complex intrarenal inflammatory processes driven by lymphocytes and innate immune cells have key roles in the development and progression of AKI. Many studies have focused on prevention of early injury in AKI. However, most patients with AKI present after injury is already established. Increasing research is therefore focusing on mechanisms of renal repair following AKI and prevention of progression from AKI to chronic kidney disease. CD4+ and CD8+ T cells, B cells and neutrophils are probably involved in the development and progression of AKI, whereas regulatory T cells, double-negative T cells and type 2 innate lymphoid cells have protective roles. Several immune cells, such as macrophages and natural killer T cells, can have both deleterious and protective effects, depending on their subtype and/or the stage of AKI. The immune system not only participates in injury and repair processes during AKI but also has a role in mediating AKI-induced distant organ dysfunction. Targeted manipulation of immune cells is a promising therapeutic strategy to improve AKI outcomes.

Dynamics of Ischemia/Reperfusion Injury Markers During Normothermic Liver Machine Perfusion

Background

A comprehensive mechanistic assessment of normothermic machine perfusion (NMP) is an essential step toward identifying biomarkers to assess liver viability. Although some studies have evaluated the effect of NMP on inflammation markers, there are other key pathological mechanisms involved in ischemia/reperfusion injury (IRI) that have not yet been evaluated.

Methods

Eight human donor livers preserved by NMP were included to analyze IRI during preservation. Concentrations of several biomarkers involved in different biological processes of IRI were measured in the perfusate.

Results

Perfusate levels of intercellular adhesion molecule 1, P-selectin, vascular cell adhesion molecule 1, metalloproteinase with thrombospondin motif type 1, member 13, phospholipase A2 group VII, and syndecan-1 progressively increased during NMP. Noteworthy, perfusate lactate levels showed a strong correlation with C-X-C motif chemokine ligand 10 (P = 0.001), intercellular adhesion molecule 1 (P = 0.01), and urokinase plasminogen activator (P = 0.001).

Conclusions

Perfusate lactate correlates with the main underlying biological mechanisms occurring in the NMP environment. Moreover, several IRI biomarkers accumulate during NMP, which may limit the extent of the benefits of this technology.

Factors Associated with the Onset of Acute Kidney Injury Following Subarachnoid Hemorrhage

BACKGROUND

Acute kidney injury (AKI) is a complication often observed in critically ill patients, indicating a worsening prognosis. However, factors predicting AKI in subarachnoid hemorrhage (SAH) patients are unclear. This study aims to elucidate the predictors of AKI occurrence.

METHODS

All patients with SAH admitted to the intensive care unit between 2013 and 2019 were included. Patients with very severe SAH who are unsuitable to receive aggressive treatment, those who previously received a contrast medium at another medical institution within 24 hours before admission, and those on maintenance dialysis were excluded. We retrospectively examined blood tests conducted upon admission, oral medications administered, and the total amount of contrast medium used after initiating treatment to investigate their association with AKI occurrence.

RESULTS

Of the 254 SAH patients treated during the relevant period, 195 (median age 64 years, 72 males) met the inclusion/exclusion criteria, and 32 patients (16.3%) developed AKI. When multivariate analysis was performed using sex, uric acid level, and hemoglobin, which obtained P < 0.01 in the univariate analysis, as variables, only uric acid level was found as an independent predictor of AKI (odds ratio, 1.501; 95% confidence interval, 1.109-2.033, P value of 0.009). There was no difference in the occurrence of AKI between survivors and nonsurvivors (12/163 vs. 2/32, P = 0.824).

CONCLUSIONS

AKI occurred in 16.3% of the patients with SAH. Patients who developed AKI had significantly higher uric acid levels. SAH with high uric acid levels warrants attention for AKI.

Joint effects of sleep disturbance and renal function impairment on incident new-onset severe metabolic dysfunction-associated steatotic liver disease

AIM

To elucidate the effects of sleep parameters and renal function on the risk of developing new-onset severe metabolic dysfunction-associated steatotic liver disease (MASLD).

MATERIALS AND METHODS

The primary analysis involved a cohort of 305 257 participants. Multivariable Cox models were employed to calculate hazard ratios and 95% confidence intervals. Traditional mediation and two-step Mendelian randomization (MR) analyses were conducted to assess the associations and mediating roles of renal function indicators between sleep and new-onset severe MASLD.

RESULTS

Poor sleep score and renal function biomarker score (RFS) were associated with an increased risk of new-onset severe MASLD (all ptrend <0.001). Participants with poor sleep patterns and the highest RFS had a 5.45-fold higher risk of new-onset severe MASLD, compared to those with healthy sleep patterns and the lowest RFS (p < 0.001). The RFS could explain 10.08% of the correlations between poor sleep score and risk of new-onset severe MASLD. Additionally, MR analyses supported a causal link between insomnia and new-onset severe MASLD and revealed a mediating role of chronic kidney disease in the connection between insomnia and new-onset severe MASLD risk.

CONCLUSIONS

This study highlights the independent and combined associations of sleep parameters and renal function indicators with new-onset severe MASLD, underscoring the bidirectional communication of the liver-kidney axis and providing modifiable strategies for preventing MASLD.

The Relationship Between Acute Kidney Injury in Sepsis Patients and Coagulation Dysfunction and Prognosis

Purpose

The aim of this study was to investigate the relationship between ARF and coagulopathy in patients with sepsis and to explore the prognostic value of these conditions.

Patients and Methods

The data of 271 patients with sepsis-associated coagulopathy admitted from June 2021 to June 2022 were reviewed. The patients were divided into a survival group and a nonsurviving group according to patient prognosis. Independent sample t tests were utilized to compare laboratory parameters within 24 hours of admission, as well as the APACHE II and SOFA scores, between the two patient groups. According to the sepsis-associated coagulation dysfunction (SAC) grading criteria for grading, Spearman correlation analysis was used to study the relationship between blood creatinine and SAC grading and assignment scores, and receiver operating characteristic (ROC) curves and Cox's proportional risk regression model were used to explore the factors affecting the prognosis of SAC patients.

Results

Spearman correlation analysis revealed strong associations between serum creatinine (Scr) concentration, SAC classification, and SAC score, with coefficients above 0.7. SAC classification outcomes varied significantly with severity: mild severity had a 77.6% survival rate versus 22.4% mortality; moderate severity had 21.5% survival versus 78.5% mortality; and severe cases had a 0.7% survival rate versus 99.3% mortality (P<0.01 for all). Multivariate analysis revealed significant predictors of outcome, including multiple organ dysfunction syndrome (MODS), with an OR of 2.070 (P=0.019); the SOFA score (OR=1.200, P<0.01); the international normalized ratio (INR) (OR=0.72, P=0.013); and the Scr level (OR=0.995, P<0.01). The areas under the ROC curves for the SOFA score, APACHE II score, and SAC classification were >0.8, all P < 0.05.

Conclusion

In patients with sepsis, SAC grade 3 or a SAC score of 4 or higher is associated with poorer prognosis, and the interaction of acute kidney injury exacerbates the degree of SAC, consequently affecting prognosis.

Objective assessment of the association between telomere length, a biomarker of aging, and health screening indicators: A cross-sectional study

Physical examination data are used to indicate individual health status and organ health, and understanding which physical examination data are indicative of physiological aging is critical for health management and early intervention. There is a lack of research on physical examination data and telomere length. Therefore, the present study analyzed the association between blood telomere length and physical examination indices in healthy people of different ages to investigate the role and association of various organs/systems with physiological aging in the human body. The present study was a cross-sectional study. Sixteen physical examination indicators of different tissue and organ health status were selected and analyzed for trends in relation to actual age and telomere length (TL). The study included 632 individuals with a total of 11,766 data for 16 physical examination indicators. Age was linearly correlated with 11 indicators. Interestingly, telomere length was strongly correlated only with the renal indicators eGFR (P < .001), CYS-C (P < .001), and SCR (P < .001). The study established that renal aging or injury is a risk factor for Physical aging of the human body. Early identification and management are essential to healthcare.

Investigating gut microbiota-blood and urine metabolite correlations in early sepsis-induced acute kidney injury: insights from targeted KEGG analyses

Background

The interplay between gut microbiota and metabolites in the early stages of sepsis-induced acute kidney injury (SA-AKI) is not yet clearly understood. This study explores the characteristics and interactions of gut microbiota, and blood and urinary metabolites in patients with SA-AKI.

Methods

Utilizing a prospective observational approach, we conducted comparative analyses of gut microbiota and metabolites via metabolomics and metagenomics in individuals diagnosed with SA-AKI compared to those without AKI (NCT06197828). Pearson correlations were used to identify associations between microbiota, metabolites, and clinical indicators. The Comprehensive Antibiotic Resistance Database was employed to detect antibiotic resistance genes (ARGs), while Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways informed on metabolic processes and microbial resistance patterns.

Results

Our study included analysis of four patients with SA-AKI and five without AKI. Significant disparities in bacterial composition were observed, illustrated by diversity indices (Shannon index: 2.0 ± 0.4 vs. 1.4 ± 0.6, P = 0.230; Simpson index: 0.8 ± 0.1 vs. 0.6 ± 0.2, P = 0.494) between the SA-AKI group and the non-AKI group. N6, N6, N6-Trimethyl-L-lysine was detected in both blood and urine metabolites, and also showed significant correlations with specific gut microbiota (Campylobacter hominis and Bacteroides caccae, R > 0, P < 0.05). Both blood and urine metabolites were enriched in the lysine degradation pathway. We also identified the citrate cycle (TCA cycle) as a KEGG pathway enriched in sets of differentially expressed ARGs in the gut microbiota, which exhibits an association with lysine degradation.

Conclusions

Significant differences in gut microbiota and metabolites were observed between the SA-AKI and non-AKI groups, uncovering potential biomarkers and metabolic changes linked to SA-AKI. The lysine degradation pathway may serve as a crucial link connecting gut microbiota and metabolites.

Unveiling cytokine charge disparity as a potential mechanism for immune regulation

Cytokines are small signaling proteins that regulate the immune responses to infection and tissue damage. Surface charges of cytokines determine their in vivo fate in immune regulation, e.g., half-life and distribution. The overall negative charges in the extracellular microenvironment and the acidosis during inflammation and infection may differentially impact cytokines with different surface charges for fine-tuned immune regulation via controlling tissue residential properties. However, the trend and role of cytokine surface charges has yet to be elucidated in the literature. Interestingly, we have observed that most pro-inflammatory cytokines have a negative charge, while most anti-inflammatory cytokines and chemokines have a positive charge. In this review, we extensively examined the surface charges of all cytokines and chemokines, summarized the pharmacokinetics and tissue adhesion of major cytokines, and analyzed the link of surface charge with cytokine biodistribution, activation, and function in immune regulation. Additionally, we identified that the general trend of charge disparity between pro- and anti-inflammatory cytokines represents a unique opportunity to develop precise immune modulation approaches, which can be applied to many inflammation-associated diseases including solid tumors, chronic wounds, infection, and sepsis.

Interorgan communication networks in the kidney-lung axis

The homeostasis and health of an organism depend on the coordinated interaction of specialized organs, which is regulated by interorgan communication networks of circulating soluble molecules and neuronal connections. Many diseases that seemingly affect one primary organ are really multiorgan diseases, with substantial secondary remote organ complications that underlie a large part of their morbidity and mortality. Acute kidney injury (AKI) frequently occurs in critically ill patients with multiorgan failure and is associated with high mortality, particularly when it occurs together with respiratory failure. Inflammatory lung lesions in patients with kidney failure that could be distinguished from pulmonary oedema due to volume overload were first reported in the 1930s, but have been largely overlooked in clinical settings. A series of studies over the past two decades have elucidated acute and chronic kidney-lung and lung-kidney interorgan communication networks involving various circulating inflammatory cytokines and chemokines, metabolites, uraemic toxins, immune cells and neuro-immune pathways. Further investigations are warranted to understand these clinical entities of high morbidity and mortality, and to develop effective treatments.

Protective efficacy of Toxoplasma gondii infected cells-derived exosomes against chronic murine toxoplasmosis

Exosomes were isolated from T. gondii infected human hepatoblastoma cells using the exosome isolation kit and characterized by electron microscopy and Western blotting. Exosomes adsorbed to alum adjuvant were evaluated as a potential immunizing agent against murine chronic toxoplasmosis compared to excretory secretory antigens (ESA)-alum. Mice were immunized at days 1, 15 and 29. The levels of IgG, IFN-γ, IL-4 and IL-10, CD4+ and CD8+ T cells were determined using sandwich enzyme-linked immunosorbent assay (sandwich ELISA) at days 14, 28 and 56 of the experiment. Then mice were infected orally with 10 cysts of T. gondii. The protective efficacy of the antigens were evaluated by counting the brain cysts and measuring the aforementioned humoral and cellular parameters 60 days post infection. The results showed that alum increased the protective efficacy of the exosomes. Immunization with exosome-alum induced both humoral and mixed Th1/Th2 cellular immune responses. Exosome-alum gave higher levels of the humoral and cellular parameters, compared to ESA-alum. After challenge infection, exosome-alum significantly reduced the brain cyst burden by 75 % while ESA-alum gave 42 % reduction and evoked higher humoral and cellular immune responses. Therefore, the possibility of using T. gondii infected cells-derived exosome-alum as a vaccine is a new perspective in toxoplasmosis.

Acute kidney injury in neurocritical care

Approximately 20% of patients with acute brain injury (ABI) also experience acute kidney injury (AKI), which worsens their outcomes. The metabolic and inflammatory changes associated with AKI likely contribute to prolonged brain injury and edema. As a result, recognizing its presence is important for effectively managing ABI and its sequelae. This review discusses the occurrence and effects of AKI in critically ill adults with neurological conditions, outlines potential mechanisms connecting AKI and ABI progression, and highlights AKI management principles. Tailored approaches include optimizing blood pressure, managing intracranial pressure, adjusting medication dosages, and assessing the type of administered fluids. Preventive measures include avoiding nephrotoxic drugs, improving hemodynamic and fluid balance, and addressing coexisting AKI syndromes. ABI patients undergoing renal replacement therapy (RRT) are more susceptible to neurological complications. RRT can negatively impact cerebral blood flow, intracranial pressure, and brain tissue oxygenation, with effects tied to specific RRT methods. Continuous RRT is favored for better hemodynamic stability and lower risk of dialysis disequilibrium syndrome. Potential RRT modifications for ABI patients include adjusted dialysate and blood flow rates, osmotherapy, and alternate anticoagulation methods. Future research should explore whether these strategies enhance outcomes and if using novel AKI biomarkers can mitigate AKI-related complications in ABI patients.

IL-6 mediates the hepatic acute phase response after prerenal azotemia in a clinically defined murine model

Prerenal azotemia (PRA) is a major cause of acute kidney injury and uncommonly studied in preclinical models. We sought to develop and characterize a novel model of PRA that meets the clinical definition: acute loss of glomerular filtration rate (GFR) that returns to baseline with resuscitation. Adult male C57BL/6J wild-type (WT) and IL-6-/- mice were studied. Intraperitoneal furosemide (4 mg) or vehicle was administered at time = 0 and 3 h to induce PRA from volume loss. Resuscitation began at 6 h with 1 mL intraperitoneal saline for four times for 36 h. Six hours after furosemide administration, measured glomerular filtration rate was 25% of baseline and returned to baseline after saline resuscitation at 48 h. After 6 h of PRA, plasma interleukin (IL)-6 was significantly increased, kidney and liver histology were normal, kidney and liver lactate were normal, and kidney injury molecule-1 immunofluorescence was negative. There were 327 differentially regulated genes upregulated in the liver, and the acute phase response was the most significantly upregulated pathway; 84 of the upregulated genes (25%) were suppressed in IL-6-/- mice, and the acute phase response was the most significantly suppressed pathway. Significantly upregulated genes and their proteins were also investigated and included serum amyloid A2, serum amyloid A1, lipocalin 2, chemokine (C-X-C motif) ligand 1, and haptoglobin; hepatic gene expression and plasma protein levels were all increased in wild-type PRA and were all reduced in IL-6-/- PRA. This work demonstrates previously unknown systemic effects of PRA that includes IL-6-mediated upregulation of the hepatic acute phase response.NEW & NOTEWORTHY Prerenal azotemia (PRA) accounts for a third of acute kidney injury (AKI) cases yet is rarely studied in preclinical models. We developed a clinically defined murine model of prerenal azotemia characterized by a 75% decrease in measured glomerular filtration rate (GFR), return of measured glomerular filtration rate to baseline with resuscitation, and absent tubular injury. Numerous systemic effects were observed, such as increased plasma interleukin-6 (IL-6) and upregulation of the hepatic acute phase response.

Platelet-to-Lymphocyte Ratio and In-Hospital Mortality in Patients With AKI Receiving Continuous Kidney Replacement Therapy: A Retrospective Observational Cohort Study

Rationale & Objective

The platelet-to-lymphocyte ratio (PLR) is a marker of inflammation and a predictor of mortality in a variety of diseases. However, the effectiveness of PLR as a predictor of mortality in patients with severe acute kidney injury (AKI) is uncertain. We evaluated the association between the PLR and mortality in critically ill patients with severe AKI who underwent continuous kidney replacement therapy (CKRT).

Study Design

Retrospective cohort study.

Setting & Participants

A total of 1,044 patients who underwent CKRT in a single center, from February 2017 to March 2021.

Exposures

PLR.

Outcomes

In-hospital mortality.

Analytical Approach

The study patients were classified into quintiles according to the PLR values. A Cox proportional hazards model was used to investigate the association between PLR and mortality.

Results

The PLR value was associated with in-hospital mortality in a nonlinear manner, showing a higher mortality at both ends of the PLR. The Kaplan-Meier curve revealed the highest mortality with the first and fifth quintiles, whereas the lowest mortality occurred with the third quintile. Compared with the third quintile, the first (adjusted HR, 1.94; 95% CI, 1.44-2.62; P < 0.001) and fifth (adjusted HR, 1.60; 95% CI, 1.18-2.18; P = 0.002) quintiles of the PLR group had a significantly higher in-hospital mortality rate. The first and fifth quintiles showed a consistently increased risk of 30- and 90-day mortality rates compared with those of the third quintile. In the subgroup analysis, the lower and higher PLR values were predictors of in-hospital mortality in patients with older age, of female sex, and with hypertension, diabetes, and higher Sequential Organ Failure Assessment score.

Limitations

There may be bias owing to the single-center retrospective nature of this study. We only had PLR values at the time of initiation of CKRT.

Conclusions

Both the lower and higher PLR values were independent predictors of in-hospital mortality in critically ill patients with severe AKI who underwent CKRT.

MCP-1/IL-12 ratio expressions correlated with adventitial collagen depositions in renal vessels and IL-4/IFN-γ expression correlated with interstitial collagen depositions in the kidneys of dogs with canine leishmaniasis

Collagen deposition is a common event in chronic inflammation, and canine Leishmaniosis (CanL) is generally associated with a long and chronic evolution. Considering that the kidney shows fibrinogenic changes during CanL, and the balance of cytokines/chemokines regulates the profibrinogenic and antifibrinogenic immune responses differently, it can be hypothesized that the balance of cytokines/chemokines can be differentially expressed in the renal tissue in order to determine the expression of collagen depositions in the kidneys. This study aimed to measure collagen deposition and to evaluate cytokine/chemokine expressions in the kidney by means of qRT-PCR in sixteen Leishmania-infected dogs and six uninfected controls. Kidney fragments were stained with hematoxylin & eosin (H&E), Masson's Trichrome, Picrosirius Red, and Gomori's reticulin. Intertubular and adventitial collagen depositions were evaluated by the morphometric approach. Cytokine RNA expressions were measured by means of qRT-PCR to identify molecules involved in chronic collagen depositions in kidneys with CanL. Collagen depositions were related to the presence of clinical signs, and more intense intertubular collagen depositions occurred in infected dogs. Adventitial collagen deposition, as morphometrically measured by the average area of the collagen, was more intense in clinically affected dogs than in subclinically infected dogs. TNF-α/TGF-β, MCP1/IL-12, CCL5/IL-12, IL-4/IFN-γ, and IL-12/TGF-β expressions were associated with clinical manifestations in dogs with CanL. The IL-4/IFN-α ratio was more commonly expressed and upregulated in clinically affected dogs, and downregulated in subclinically infected dogs. Furthermore, MCP-1/IL-12 and CCL5/IL-12 were more commonly expressed in subclinically infected dogs. Strong positive correlations were detected between morphometric values of interstitial collagen depositions and MCP-1/IL-12, IL-12, and IL-4 mRNA expression levels in the renal tissues. Adventitial collagen deposition was correlated with TGF-β, IL-4/IFN-γ, and TNF-α/TGF-β. In conclusion, our results showed the association of MCP-1/IL-12 and CCL5/IL-12 ratios with an absence of clinical signs, as well as an IL-4/IFN-α ratio with adventitial and intertubular collagen depositions in dogs with visceral leishmaniosis.

New Frontiers in Sepsis-Induced Acute Kidney Injury and Blood Purification Therapies: The Role of Polymethylmethacrylate Membrane Hemofilter

Acute kidney injury (AKI) is a common consequence of sepsis with a mortality rate of up to 40%. The pathogenesis of septic AKI is complex and involves several mechanisms leading to exacerbated inflammatory response associated with renal injury. A large body of evidence suggests that inflammation is tightly linked to AKI through bidirectional interaction between renal and immune cells. Preclinical data from our and other laboratories have identified in complement system activation a crucial mediator of AKI. Partial recovery following AKI could lead to long-term consequences that predispose to chronic dysfunction and may also accelerate the progression of preexisting chronic kidney disease. Recent findings have revealed striking morphological and functional changes in renal parenchymal cells induced by mitochondrial dysfunction, cell cycle arrest via the activation of signaling pathways involved in aging process, microvascular rarefaction, and early fibrosis. Although major advances have been made in our understanding of the pathophysiology of AKI, there are no available preventive and therapeutic strategies in this field. The identification of ideal clinical biomarkers for AKI enables prompt and effective therapeutic strategy that could prevent the progression of renal injury and promote repair process. Therefore, the use of novel biomarkers associated with clinical and functional criteria could provide early interventions and better outcome. Several new drugs for AKI are currently being investigated; however, the complexity of this disease might explain the failure of pharmacological intervention targeting just one of the many systems involved. The hypothesis that blood purification could improve the outcome of septic AKI has attracted much attention. New relevant findings on the role of polymethylmethacrylate-based continuous veno-venous hemofiltration in septic AKI have been reported. Herein, we provide a comprehensive literature review on advances in the pathophysiology of septic AKI and potential therapeutic approaches in this field.

Comparison of Clinical Characteristics and Predictors of Mortality between Direct and Indirect ARDS

Background and Objectives: Acute Respiratory Distress Syndrome (ARDS) is a heterogeneous syndrome that encompasses lung injury from a direct pulmonary or indirect systemic insult. Studies have shown that direct and indirect ARDS differ in their pathophysiologic process. In this study, we aimed to compare the different clinical characteristics and predictors of 28-day mortality between direct and indirect ARDS. Materials and Methods: The data of 1291 ARDS patients from September 2012 to December 2021 at the Second Affiliated Hospital of Chongqing Medical University were reviewed. We enrolled 451 ARDS patients in our study through inclusion and exclusion criteria. According to the risk factors, each patient was divided into direct (n = 239) or indirect (n = 212) ARDS groups. The primary outcome was 28-day mortality. Results: The patients with direct ARDS were more likely to be older (p < 0.001) and male (p = 0.009) and have more comorbidity (p < 0.05) and higher 28-day mortality (p < 0.001) than those with indirect ARDS. Age and multiple organ dysfunction syndrome (MODS) were predictors of 28-day mortality in the direct ARDS group, while age, MODS, creatinine, prothrombin time (PT), and oxygenation index (OI) were independent predictors of 28-day mortality in the indirect ARDS group. Creatinine, PT, and OI have interactions with ARDS types (all p < 0.01). Conclusions: The patients with direct ARDS were more likely to be older and male and have worse conditions and prognoses than those with indirect ARDS. Creatinine, PT, and OI were predictors of 28-day mortality only in the indirect ARDS group. The differences between direct and indirect ARDS suggest the need for different management strategies of ARDS.

Sepsis and Acute Kidney Injury: A Review Focusing on the Bidirectional Interplay

Although sepsis and acute kidney injury (AKI) have a bidirectional interplay, the pathophysiological mechanisms between AKI and sepsis are not clarified and worthy of a comprehensive and updated review. The primary pathophysiology of sepsis-associated AKI (SA-AKI) includes inflammatory cascade, macrovascular and microvascular dysfunction, cell cycle arrest, and apoptosis. The pathophysiology of sepsis following AKI contains fluid overload, hyperinflammatory state, immunosuppression, and infection associated with kidney replacement therapy and catheter cannulation. The preventive strategies for SA-AKI are non-specific, mainly focusing on infection control and preventing further kidney insults. On the other hand, the preventive strategies for sepsis following AKI might focus on decreasing some metabolites, cytokines, or molecules harmful to our immunity, supplementing vitamin D3 for its immunomodulation effect, and avoiding fluid overload and unnecessary catheter cannulation. To date, several limitations persistently prohibit the understanding of the bidirectional pathophysiologies. Conducting studies, such as the Kidney Precision Medicine Project, to investigate human kidney tissue and establishing parameters or scores better to determine the occurrence timing of sepsis and AKI and the definition of SA-AKI might be the prospects to unveil the mystery and improve the prognoses of AKI patients.

Crosstalk between kidney and liver in non-alcoholic fatty liver disease: mechanisms and therapeutic approaches

Liver and kidney are vital organs that maintain homeostasis and injury to either of them triggers pathogenic pathways affecting the other. For example, non-alcoholic fatty liver disease (NAFLD) promotes the progression of chronic kidney disease (CKD), vice versa acute kidney injury (AKI) endorses the induction and progression of liver dysfunction. Progress in clinical and basic research suggest a role of excessive fructose intake, insulin resistance, inflammatory cytokines production, activation of the renin-angiotensin system, redox imbalance, and their impact on epigenetic regulation of gene expression in this context. Recent developments in experimental and clinical research have identified several biochemical and molecular pathways for AKI-liver interaction, including altered liver enzymes profile, metabolic acidosis, oxidative stress, activation of inflammatory and regulated cell death pathways. This review focuses on the current preclinical and clinical findings on kidney-liver crosstalk in NAFLD-CKD and AKI-liver dysfunction settings and highlights potential molecular mechanisms and therapeutic targets.

Acute kidney injury associated to COVID-19 leads to a strong unbalance of circulant immune mediators

BACKGROUND

Severe cases of coronavirus disease 2019 (COVID-19) have increased risk for acute kidney injury (AKI). The exacerbation of the immune response seems to contribute to AKI development, but the immunopathological process is not completely understood.

OBJECTIVES

To analyze levels of circulant immune mediators in COVID-19 patients evolving with or without AKI. We have also investigated possible associations of these mediators with viral load and clinical outcomes.

METHODS

This is a longitudinal study performed with hospitalized patients with moderate to severe COVID-19. Serum levels of 27 immune mediators were measured by a multiplex immunoassay. Data were analyzed at two timepoints during the follow-up: within the first 13 days of the disease onset (early sample) and from the 14th day to death or hospital discharge (follow-up sample).

RESULTS

We studied 82 COVID-19 patients (59.5 ± 17.5 years, 54.9% male). Of these, 34 (41.5%) developed AKI. These patients presented higher SARS-CoV-2 viral load (P = 0.03), higher frequency of diabetes (P = 0.01) and death (P = 0.0004). Overall, AKI patients presented significantly higher and sustained levels (P < 0.05) of CCL-2, CCL-3, CCL-4, CXCL-8, CXCL-10, IFN-γ, IL-2, IL-6, TNF-α, IL-1Ra, IL-10 and VEGF. Importantly, higher levels of CCL-2, CXCL-10, IL-2, TNF-α, IL-10, FGFb, and VEGF were observed in AKI patients independently of death. ROC curves demonstrated that early alterations in CCL-2, CXCL-8, CXCL-10, IFN-γ, IL-6, IL-1Ra and IL-10 show a good predictive value regarding AKI development. Lastly, immune mediators were significantly associated with each other and with SARS-CoV-2 viral load in AKI patients.

CONCLUSIONS

COVID-19 associated AKI is accompanied by substantial alterations in circulant levels of immune mediators, which could significantly contribute to the establishment of kidney injury.

The Role of Systemic Filtrating Organs in Aging and Their Potential in Rejuvenation Strategies

Advances in aging studies brought about by heterochronic parabiosis suggest that aging might be a reversable process that is affected by changes in the systemic milieu of organs and cells. Given the broadness of such a systemic approach, research to date has mainly questioned the involvement of “shared organs” versus “circulating factors”. However, in the absence of a clear understanding of the chronological development of aging and a unified platform to evaluate the successes claimed by specific rejuvenation methods, current literature on this topic remains scattered. Herein, aging is assessed from an engineering standpoint to isolate possible aging potentiators via a juxtaposition between biological and mechanical systems. Such a simplification provides a general framework for future research in the field and examines the involvement of various factors in aging. Based on this simplified overview, the kidney as a filtration organ is clearly implicated, for the first time, with the aging phenomenon, necessitating a re-evaluation of current rejuvenation studies to untangle the extent of its involvement and its possible role as a potentiator in aging. Based on these findings, the review concludes with potential translatable and long-term therapeutics for aging while offering a critical view of rejuvenation methods proposed to date.

Experimental models of acute kidney injury for translational research

Preclinical models of human disease provide powerful tools for therapeutic discovery but have limitations. This problem is especially apparent in the field of acute kidney injury (AKI), in which clinical trial failures have been attributed to inaccurate modelling performed largely in rodents. Multidisciplinary efforts such as the Kidney Precision Medicine Project are now starting to identify molecular subtypes of human AKI. In addition, over the past decade, there have been developments in human pluripotent stem cell-derived kidney organoids as well as zebrafish, rodent and large animal models of AKI. These organoid and AKI models are being deployed at different stages of preclinical therapeutic development. However, the traditionally siloed, preclinical investigator-driven approaches that have been used to evaluate AKI therapeutics to date rarely account for the limitations of the model systems used and have given rise to false expectations of clinical efficacy in patients with different AKI pathophysiologies. To address this problem, there is a need to develop more flexible and integrated approaches, involving teams of investigators with expertise in a range of different model systems, working closely with clinical investigators, to develop robust preclinical evidence to support more focused interventions in patients with AKI.

Interorgan crosstalk mechanisms in disease: the case of acute kidney injury-induced remote lung injury

Homeostasis and health of multicellular organisms with multiple organs depends on interorgan communication. Tissue injury in one organ disturbs this homeostasis and can lead to disease in multiple organs, or multiorgan failure. Many routes of interorgan crosstalk during homeostasis are relatively well known, but interorgan crosstalk in disease still lacks understanding. In particular, how tissue injury in one organ can drive injury at remote sites and trigger multiorgan failure with high mortality is poorly understood. As examples, acute kidney injury can trigger acute lung injury and cardiovascular dysfunction; pneumonia, sepsis or liver failure conversely can cause kidney failure; lung transplantation very frequently triggers acute kidney injury. Mechanistically, interorgan crosstalk after tissue injury could involve soluble mediators and their target receptors, cellular mediators, in particular immune cells, as well as newly identified neuro-immune connections. In this review, I will focus the discussion of deleterious interorgan crosstalk and its mechanistic concepts on one example, acute kidney injury-induced remote lung injury.

Interaction of Acute Respiratory Failure and Acute Kidney Injury on in-Hospital Mortality of Patients with Acute Exacerbation COPD

Purpose

Both acute respiratory failure (ARF) and acute kidney injury (AKI) are two common complications in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Moreover, both ARF and AKI are reported as increasing the risk of mortality of patients with AECOPD. However, the interaction of ARF and AKI on the mortality of patients with AECOPD remains unknown. Therefore, the aim of this study is to investigate the joint effect of ARF and AKI on in-hospital mortality in AECOPD patients.

Patients and Methods

We performed a retrospective, observational cohort study of data from Nanjing First Hospital. The effect of AKI and ARF on in-hospital mortality was assessed using a multivariate logistic regression model. Additive interaction was assessed with the relative excess risk due to interaction.

Results

A total of 1647 participants were enrolled. ARF and AKI occurred in 515 (31.3%) and 357 (21.7%) patients, respectively. Overall, in-hospital mortality was 5.7%. The in-hospital mortality of the neither ARF nor AKI group, the ARF only group, the AKI only group, and both the ARF and AKI group were 0.8%, 7.0%, 7.5%, and 29.9%, respectively. After multivariate logistic regression analysis, the independent factors for in-hospital death included: albumin (OR 0.88, 95% CI 0.83–0.93, P < 0.001), ARF only (OR 8.53, 95% CI 3.64–19.99, P < 0.001), AKI only (OR 8.99, 95% CI 3.58–22.55, P < 0.001), and both ARF and AKI (OR 39.13, 95% CI 17.02–89.97, P < 0.001). The relative excess risk due to interaction was 22.62 (95% CI, 0.31 to 44.93), the attributable proportion due to interaction was 0.59 (95% CI, 0.36 to 0.79), and the synergy index was 2.46 (95% CI, 1.44 to 4.20), indicating ARF and AKI had a significant synergic effect on in-hospital mortality.

Conclusion

ARF and AKI had a synergistic effect on in-hospital mortality in AECOPD patients.

Acute Kidney Injury at the Neurocritical Care Unit

Neurocritical care has advanced substantially in recent decades, allowing doctors to treat patients with more complicated conditions who require a multidisciplinary approach to achieve better clinical outcomes. In neurocritical patients, nonneurological complications such as acute kidney injury (AKI) are independent predictors of worse clinical outcomes. Different research groups have reported an AKI incidence of 11.6% and an incidence of stage 3 AKI, according to the Kidney Disease: Improving Global Outcomes, that requires dialysis of 3% to 12% in neurocritical patients. These patients tend to be younger, have less comorbidity, and have a different risk profile, given the diagnostic and therapeutic procedures they undergo. Trauma-induced AKI, sepsis, sympathetic overstimulation, tubular epitheliopathy, hyperchloremia, use of nephrotoxic drugs, and renal hypoperfusion are some of the causes of AKI in neurocritical patients. AKI is the result of a sum of events, although the mechanisms underlying many of them remain uncertain; however, two important causes that merit mention are direct alteration of the physiological brain-kidney connection and exposure to injury as a result of the specific medical management and well-established therapies that neurocritical patients are subjected to. This review will focus on AKI in neurocritical care patients. Specifically, it will discuss its epidemiology, causes, associated mechanisms, and relationship to the brain-kidney axis. Additionally, the use and risks of extracorporeal therapies in this group of patients will be reviewed.

Naringin and Trimetazidine Improve Baroreflex Sensitivity and Nucleus Tractus Solitarius Electrical Activity in Renal Ischemia-Reperfusion Injury

BACKGROUND

Nucleus tractus solitarius (NTS) is a brain area that plays a key role in kidney and cardiovascular regulation via baroreceptors impulses.

OBJECTIVES

The aim of this study was to evaluate the effect of naringin (NAR) and trimetazidine (TMZ) alone and their combination on NTS electrical activity and baroreceptor sensitivity (BRS) in renal ischemia- reperfusion (I/R) injury.

METHODS

Forty male Sprague-Dawley rats (200- 250 g) were allocated into 5 groups with 8 in each. 1) Sham; 2) I/R; 3) TMZ 5 mg/kg; 4) NAR 100 mg/kg; and 5) TMZ5+ NAR100. The left femoral vein was cannulated to infuse saline solution or drug and the BRS was evaluated. I/R was induced by occlusion of renal pedicles for 45 min, followed by 4 hours of reperfusion. The NTS local electroencephalogram (EEG) was recorded before, during ischemia and throughout the reperfusion. Phenylephrine was injected intravenously to evaluate BRS at the end of reperfusion time. The data were analyzed by two-way repeated measurement ANOVA followed by Tukey's post hoc test. A p-value <0.05 was considered significant.

RESULTS

NTS electrical waves did not change during ischemia time, while they significantly decreased during the entire reperfusion time. NTS electrical activity and BRS dramatically reduced in rats with I/R injury; however, administration of NAR, TMZ alone or their combination significantly improved these changes in rats with I/R injury.

CONCLUSIONS

The results showed that I/R injury leads to reduced BRS and NTS electrical activity and there may be an association between I/R and decreased BRS. In addition, NAR and TMZ are promising agents to treat I/R complications.

Gut Microbiota Dysbiosis Is a Crucial Player for the Poor Outcomes for COVID-19 in Elderly, Diabetic and Hypertensive Patients

A new infectious disease, named COVID-19, caused by the coronavirus associated to severe acute respiratory syndrome (SARS-CoV-2) has become pandemic in 2020. The three most common pre-existing comorbidities associated with COVID-19-related death are elderly, diabetic, and hypertensive people. A common factor among these risk groups for the outcome of death in patients infected with SARS-CoV-2 is dysbiosis, with an increase in the proportion of bacteria with a pro-inflammatory profile. Due to this dysbiosis, elderly, diabetic, and hypertensive people present a higher propensity to mount an inflammatory environment in the gut with poor immune editing, culminating in a weakness of the intestinal permeability barrier and high bacterial product translocation to the bloodstream. This scenario culminates in a low-grade, persistent, and systemic inflammation. In this context, we propose here that high circulating levels of bacterial products, like lipopolysaccharide (LPS), can potentiate the SARS-CoV-2-induced cytokines, including IL-6, being crucial for development of the cytokine storm in the severe form of the disease. A better understanding on the possible correlation between gut dysbiosis and poor outcomes observed in elderly, diabetic, and hypertensive people can be useful for the development of new therapeutic strategies based on modulation of the gut microbiota.

Beyond the Brain: Peripheral Interactions after Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of death and disability, and there are currently no pharmacological treatments known to improve patient outcomes. Unquestionably, contributing toward a lack of effective treatments is the highly complex and heterogenous nature of TBI. In this review, we highlight the recent surge of research that has demonstrated various central interactions with the periphery as a potential major contributor toward this heterogeneity and, in particular, the breadth of research from Australia. We describe the growing evidence of how extracranial factors, such as polytrauma and infection, can significantly alter TBI neuropathology. In addition, we highlight how dysregulation of the autonomic nervous system and the systemic inflammatory response induced by TBI can have profound pathophysiological effects on peripheral organs, such as the heart, lung, gastrointestinal tract, liver, kidney, spleen, and bone. Collectively, this review firmly establishes TBI as a systemic condition. Further, the central and peripheral interactions that can occur after TBI must be further explored and accounted for in the ongoing search for effective treatments.

Roflumilast improves resolution of sepsis-induced acute kidney injury by retarding late phase renal interstitial immune cells infiltration and leakage in urinary sediments

Some evidence has demonstrated that both inflammation and immune cell dysregulation are coincident at late phase (post 24 h) of sepsis. The present study was designed to determine the pathological role of hyperinflammation and renal immune cells mobilization during late phase of sepsis induced acute kidney injury (S-AKI) and tests the pharmacological effects of PDE-4 inhibitor on these events. Sepsis was induced by cecal ligation puncture and renal function, oxidative-inflammatory stress biomarkers were assessed after 24 h. PDE-4 inhibitor was administered for 7 days prior to induction of S-AKI. Renal immune cells infiltration during sepsis was analyzed by H&E staining and papanicolaou staining method was used for detecting leukocytes and cast in urinary sediments, periodic acid schiff (PAS) staining was used for detection of brush border loss. AKI developed 24 h post sepsis insult as depicted by increase in serum creatinine, blood urea nitrogen (BUN), renal oxidative stress, and elevated inflammatory biomarkers levels. Moreover, septic rats displayed increased bacterial load, renal expression of phosphodiesterase-4B, 4D isoforms, enhanced vascular permeability, caspase-3 and myeloperoxidase activity, electrolyte imbalance, reduced Na⁺ K⁺ ATPase activity, declined cAMP levels, increased interstitial leukocyte infiltration, and leakage in urinary sediments along with histological alterations. Pre-treatment with roflumilast at high dose completely prevented the various AKI associated manifestations in septic rats. Renal hyper-inflammation and leukocyte infiltration was detected in late phase of S-AKI. Roflumilast pre-treatment resolved sepsis induced renal dysfunction and histological damage by suppressing late phase renal immune cells invasion and anti-inflammatory effects mediated by up-regulation of renal cAMP levels.

Lung metabolomics after ischemic acute kidney injury reveals increased oxidative stress, altered energy production, and ATP depletion

Acute kidney injury (AKI) is a complex disease associated with increased mortality that may be due to deleterious distant organ effects. AKI associated with respiratory complications, in particular, has a poor outcome. In murine models, AKI is characterized by increased circulating cytokines, lung chemokine upregulation, and neutrophilic infiltration, similar to other causes of indirect acute lung injury (ALI; e.g., sepsis). Many causes of lung inflammation are associated with a lung metabolic profile characterized by increased oxidative stress, a shift toward the use of other forms of energy production, and/or a depleted energy state. To our knowledge, there are no studies that have evaluated pulmonary energy production and metabolism after AKI. We hypothesized that based on the parallels between inflammatory acute lung injury and AKI-mediated lung injury, a similar metabolic profile would be observed. Lung metabolomics and ATP levels were assessed 4 h, 24 h, and 7 days after ischemic AKI in mice. Numerous novel findings regarding the effect of AKI on the lung were observed including 1) increased oxidative stress, 2) a shift toward alternate methods of energy production, and 3) depleted levels of ATP. The findings in this report bring to light novel characteristics of AKI-mediated lung injury and provide new leads into the mechanisms by which AKI in patients predisposes to pulmonary complications.

Changes of Urinary Cytokines in Non-Diabetic Obese Patients After Laparoscopic Sleeve Gastrectomy

INTRODUCTION

Adipose tissues synthesize and secrete various proinflammatory and anti-inflammatory mediators, termed cytokines. This work aims to assess different serum and urinary cytokine levels before and 12 months after laparoscopic sleeve gastrectomy (LSG).

PATIENTS

This prospective study was performed on 61 obese non-diabetic patients who underwent LSG. All patients were followed up postoperatively at 12 months with the assessment of arterial blood pressure, microalbuminuria, urinary and serum levels of inflammatory cytokines (macrophage migration inhibitory factor "MIF," monocyte chemotactic protein "MCP"-1, chemokine (C-C motif) ligand 15 (CCL-15), and CCL-18), in addition to serum creatinine, total cholesterol, and C-reactive protein (CRP).

RESULTS

Mean BMI showed decreased substantially from 44.78 ± 3.59 Kg/m2 to 34.56 ± 2.45. Systolic blood pressure decreased from 147.03 ± 16.89 mmHg to 128.82 ± 12.52 and diastolic blood pressure decreased from 90.51 ± 12.71 mmHg to 79.69 ± 10.39. At one-year of follow-up, there was statistically significant decrease of mean serum creatinine, total cholesterol, CRP, CCL-15, CCL-18, MIF/creatinine ratio, MCP-1/creatinine ratio, CCL-15/creatinine ratio, and CCL-18/creatinine ratio (P value <0.001).

CONCLUSION

Improvement of systemic and renal inflammatory states after LSG may positively affect obesity-related renal disease by steering the adipokine levels towards anti-inflammatory profiles.

Renohepatic crosstalk: a review of the effects of acute kidney injury on the liver

Several theories regarding acute kidney injury (AKI)-related mortality have been entertained, although mounting evidence supports the paradigm that impaired kidney function directly and adversely affects the function of several remote organs. The kidneys and liver are fundamental to human metabolism and detoxification, and it is therefore hardly surprising that critical illness complicated by hepatorenal dysfunction portends a poor prognosis. Several diseases can simultaneously impact the proper functioning of the liver and kidneys, although this review will address the impact of AKI on liver function. While evidence for this relationship in humans remains sparse, we present supportive studies and then discuss the most likely mechanisms by which AKI can cause liver dysfunction. These include 'traditional' complications of AKI (uremia, volume overload and acute metabolic acidosis, among others) as well as systemic inflammation, hepatic leukocyte infiltration, cytokine-mediated liver injury and hepatic oxidative stress. We conclude by addressing the therapeutic implications of these findings to clinical medicine.

Kidney injury in COVID-19

Coronavirus disease 2019 (COVID-19) continues to affect millions of people around the globe. As data emerge, it is becoming more evident that extrapulmonary organ involvement, particularly the kidneys, highly influence mortality. The incidence of acute kidney injury has been estimated to be 30% in COVID-19 non-survivors. Current evidence suggests four broad mechanisms of renal injury: Hypovolaemia, acute respiratory distress syndrome related, cytokine storm and direct viral invasion as seen on renal autopsy findings. We look to critically assess the epidemiology, pathophysiology and management of kidney injury in COVID-19.

A call to action to evaluate renal functional reserve in patients with COVID-19

Coronavirus disease 2019 (COVID-19) poses an unprecedented challenge to world health systems, substantially increasing hospitalization and mortality rates in all affected countries. Being primarily a respiratory disease, COVID-19 is mainly associated with pneumonia or minor upper respiratory tract symptoms; however, different organs can sustain considerable (if not terminal) damage because of coronavirus. Acute kidney injury is the most common complication of COVID-19-related pneumonia, and more than 20% of patients requiring ventilatory support develop renal failure. Additionally, chronic kidney disease is a major risk factor for COVID-19 severity and mortality. All these data demonstrate the relevance of renal function assessment in patients with COVID-19 and the need of early kidney-directed diagnostic and therapeutic approaches. However, the sole assessment of renal function could be not entirely indicative of kidney tissue status. In this viewpoint, we discuss the clinical significance and potential relevance of renal functional reserve evaluation in patients with COVID-19.

The endogenous capacity to produce proinflammatory mediators by the ex vivo human perfused lung

Background

The ex vivo human perfused lung model has enabled optimizing donor lungs for transplantation and delineating mechanisms of lung injury. Perfusate and airspace biomarkers are a proxy of the lung response to experimental conditions. However, there is a lack of studies evaluating biomarker kinetics during perfusion and after exposure to stimuli. In this study, we analyzed the ex vivo-perfused lung response to three key perturbations: exposure to the perfusion circuit, exogenous fresh whole blood, and bacteria.

Results

Ninety-nine lungs rejected for transplantation underwent ex vivo perfusion. One hour after reaching experimental conditions, fresh whole blood was added to the perfusate (n = 55). Two hours after reaching target temperature, Streptococcus pneumoniae was added to the perfusate (n = 42) or to the airspaces (n = 17). Perfusate and airspace samples were collected at baseline (once lungs were equilibrated for 1 h, but before blood or bacteria were added) and 4 h later. Interleukin (IL)-6, IL-8, angiopoietin (Ang)-2, and soluble tumor necrosis factor receptor (sTNFR)-1 were quantified. Baseline perfusate and airspace biomarker levels varied significantly, and this was not related to pre-procurement P_aO₂:FiO₂ ratio, cold ischemia time, and baseline alveolar fluid clearance (AFC). After 4 h of ex vivo perfusion, the lung demonstrated a sustained production of proinflammatory mediators. The change in biomarker levels was not influenced by baseline donor lung characteristics (cold ischemia time, baseline AFC) nor was it associated with measures of experimental epithelial (final AFC) or endothelial (percent weight gain) injury. In the presence of exogenous blood, the rise in biomarkers was attenuated. Lungs exposed to intravenous (IV) bacteria relative to control lungs demonstrated a significantly higher rise in perfusate IL-6.

Conclusions

The ex vivo-perfused lung has a marked endogenous capacity to produce inflammatory mediators over the course of short-term perfusion that is not significantly influenced by donor lung characteristics or the presence of exogenous blood, and only minimally affected by the introduction of systemic bacteremia. The lack of association between biomarker change and donor lung cold ischemia time, final alveolar fluid clearance, and experimental percent weight gain suggests that the maintained ability of the human lung to produce biomarkers is not merely a marker of lung epithelial or endothelial injury, but may support the function of the lung as an immune cell reservoir.

[Acute renal failure during COVID-19 epidemic]

L’atteinte rénale est une complication fréquemment rencontrée chez les patients hospitalisés en unité de soins intensifs pour syndrome de détresse respiratoire aiguë (SDRA) dû à la COVID-19. Sa prévalence semble différente à travers le monde. Plusieurs mécanismes physiopathologiques sont impliqués, parmi lesquelles une hypoperfusion rénale liée à la ventilation mécanique, au sepsis et à l’orage cytokinique, ainsi qu’une toxicité directe du virus sur les cellules tubulaires proximales et les podocytes, médiée par les récepteurs de conversion de l’angiotensine 2 (ACE 2) et les protéases TMPRSS. Le recours à l’épuration extrarénale (EER) est de l’ordre de 20 % chez les patients de réanimation. La dialyse est rendue difficile par l’état d’hypercoagulabilité des patients atteints du SARS-CoV-2, qui provoque des thromboses précoces du filtre.

Kidney Ischemia-Reperfusion Elicits Acute Liver Injury and Inflammatory Response

Ischemia-reperfusion (IR) is a common risk factor that causes acute kidney injury (AKI). AKI is associated with dysfunction of other organs also known as distant organ injury. The liver function is often compromised in patients with AKI and in animal models. However, the underlying mechanisms are not fully understood. Inflammatory response plays an important role in IR-induced tissue injury. Although increased proinflammatory cytokines have been detected in the kidney and the distant organs after renal IR, their original sources remain uncertain. In the present study, we investigated the acute effect of renal IR on hepatic inflammatory cytokine expression and the mechanism involved. Sprague-Dawley rats that were subjected to renal IR (ischemia for 45 min followed by reperfusion for 1 h or 6 h) had increased plasma levels of creatinine, urea, and transaminases, indicating kidney and liver injuries. There was a significant increase in the expression of proinflammatory cytokine mRNA (MCP-1, TNF-α, IL-6) in the kidney and liver in rats with renal IR. This was accompanied by a significant increase in proinflammatory cytokine protein levels in the plasma, kidney, and liver. Activation of a nuclear transcription factor kappa B (NF-κB) was detected in the liver after renal IR. The inflammatory foci and an increased myeloperoxidase (MPO) activity were detected in the liver after renal IR, indicating hepatic inflammatory response and leukocyte infiltration. These results suggest that renal IR can directly activate NF-κB and induce acute production of proinflammatory cytokines in the liver. Renal IR-induced hepatic inflammatory response may contribute to impaired liver function and systemic inflammation.

Lung-kidney interactions in critically ill patients: consensus report of the Acute Disease Quality Initiative (ADQI) 21 Workgroup

BACKGROUND

Multi-organ dysfunction in critical illness is common and frequently involves the lungs and kidneys, often requiring organ support such as invasive mechanical ventilation (IMV), renal replacement therapy (RRT) and/or extracorporeal membrane oxygenation (ECMO).

METHODS

A consensus conference on the spectrum of lung-kidney interactions in critical illness was held under the auspices of the Acute Disease Quality Initiative (ADQI) in Innsbruck, Austria, in June 2018. Through review and critical appraisal of the available evidence, the current state of research, and both clinical and research recommendations were described on the following topics: epidemiology, pathophysiology and strategies to mitigate pulmonary dysfunction among patients with acute kidney injury and/or kidney dysfunction among patients with acute respiratory failure/acute respiratory distress syndrome. Furthermore, emphasis was put on patients receiving organ support (RRT, IMV and/or ECMO) and its impact on lung and kidney function.

CONCLUSION

The ADQI 21 conference found significant knowledge gaps about organ crosstalk between lung and kidney and its relevance for critically ill patients. Lung protective ventilation, conservative fluid management and early recognition and treatment of pulmonary infections were the only clinical recommendations with higher quality of evidence. Recommendations for research were formulated, targeting lung-kidney interactions to improve care processes and outcomes in critical illness.

Distant organ dysfunction in acute kidney injury

Acute kidney injury (AKI) is a common complication in critically ill patients and it is associated with increased morbidity and mortality. Epidemiological and clinical data show that AKI is linked to a wide range of distant organ injuries, with the lungs, heart, liver, and intestines representing the most clinically relevant affected organs. This distant organ injury during AKI predisposes patients to progression to multiple organ dysfunction syndrome and ultimately, death. The strongest direct evidence of distant organ injury occurring in AKI has been obtained from animal models. The identified mechanisms include systemic inflammatory changes, oxidative stress, increases in leucocyte trafficking and the activation of proapoptotic pathways. Understanding the pathways driving AKI-induced distal organ injury are critical for the development and refinement of therapies for the prevention and attenuation of AKI-related morbidity and mortality. The purpose of this review is to summarize both clinical and preclinical studies of AKI and its role in distant organ injury.

Management of Acute Kidney Injury in the Setting of Acute Respiratory Distress Syndrome: Review Focusing on Ventilation and Fluid Management Strategies

Acute respiratory distress syndrome (ARDS) is a major cause of mortality in adults with acute hypoxic respiratory failure and can predispose those afflicted to develop acute kidney injury (AKI). In the setting where AKI and ARDS overlap, incidence of mortality, length of intensive care unit stay, and complexity of management increases drastically. Lung protective ventilation strategy and conservative fluid management are the main focus of therapy in patients with ARDS, but have major implications on renal function. This review aims to provide concise discussion of pathophysiology, ventilation, and fluid management strategies as it relates to AKI in the setting of ARDS.

Acute kidney injury in Ugandan children with severe malaria is associated with long-term behavioral problems

Background

Acute kidney injury (AKI) is a risk factor for neurocognitive impairment in severe malaria (SM), but the impact of AKI on long-term behavioral outcomes following SM is unknown.

Methods

We conducted a prospective study on behavioral outcomes of Ugandan children 1.5 to 12 years of age with two forms of severe malaria, cerebral malaria (CM, n = 226) or severe malarial anemia (SMA, n = 214), and healthy community children (CC, n = 173). AKI was defined as a 50% increase in creatinine from estimated baseline. Behavior and executive function were assessed at baseline and 6, 12, and 24 months later using the Child Behavior Checklist and Behavior Rating Inventory of Executive Function, respectively. Age-adjusted z-scores were computed for each domain based on CC scores. The association between AKI and behavioral outcomes was evaluated across all time points using linear mixed effect models, adjusting for sociodemographic variables and disease severity.

Results

AKI was present in 33.2% of children with CM or SMA at baseline. Children ≥6 years of age with CM or SMA who had AKI on admission had worse scores in socio-emotional function in externalizing behaviors (Beta (95% CI), 0.52 (0.20, 0.85), p = 0.001), global executive function (0.48 (0.15, 0.82), p = 0.005) and behavioral regulation (0.66 (0.32, 1.01), p = 0.0002) than children without AKI. There were no behavioral differences associated with AKI in children <6 years of age.

Conclusions

AKI is associated with long-term behavioral problems in children ≥6 years of age with CM or SMA, irrespective of age at study enrollment.

Acute kidney injury and adverse outcomes of critical illness: correlation or causation?

Critically ill patients who develop acute kidney injury (AKI) are more than twice as likely to die in hospital. However, it is not clear to what extent AKI is the cause of excess mortality, or merely a correlate of illness severity. The Bradford Hill criteria for causality (plausibility, temporality, magnitude, specificity, analogy, experiment & coherence, biological gradient and consistency) were applied to assess the extent to which AKI may be causative in adverse short-term outcomes of critical illness.

Plausible mechanisms exist to explain increased risk of death after AKI, both from direct pathophysiological effects of renal dysfunction and mechanisms of organ cross-talk in multiple-organ failure. The temporal relationship between increased mortality following AKI is consistent with its pathophysiology. AKI is associated with substantially increased mortality, an association that persists after accounting for known confounders. A biological gradient exists between increasing severity of AKI and increasing short-term mortality. This graded association shares similar features to the increased mortality observed in ARDS; an analogous condition with a multifactorial aetiology. Evidence for the outcomes of AKI from retrospective cohort studies and experimental animal models is coherent however both of these forms of evidence have intrinsic biases and shortcomings. The relationship between AKI and risk of death is maintained across a range of patient ages, comorbidities and underlying diagnoses.

In conclusion many features of the relationship between AKI and short-term mortality suggest causality. Prevention and mitigation of AKI and its complications are valid targets for studies seeking to improve short-term survival in critical care.

[Predictive value of plasma cytokines for acute kidney injury following lung resection surgery: prospective observational study]

BACKGROUND AND OBJECTIVES

Patients undergoing lung resection surgery are at risk of developing postoperative acute kidney injury. Determination of cytokine levels allows the detection of an early inflammatory response. We investigated any temporal relationship among perioperative inflammatory status and development of acute kidney injury after lung resection surgery. Furthermore, we evaluated the impact of acute kidney injury on outcome and analyzed the feasibility of cytokines to predict acute kidney injury.

METHODS

We prospectively analyzed 174 patients scheduled for elective lung resection surgery with intra-operative periods of one-lung ventilation. Fiberoptic broncho-alveolar lavage was performed in each lung before and after one-lung ventilation periods for cytokine analysis. As well, cytokine levels were measured from arterial blood samples at five time points. Acute kidney injury was diagnosed within 48h of surgery based estabilished criteria for its diagnosis. We analyzed the association between acute kidney injury and cardiopulmonary complications, length of intensive care unit and hospital stays, intensive care unit re-admission, and short-term and long-term mortality.

RESULTS

The incidence of acute kidney injury in our study was 6.9% (12/174). Acute kidney injury patients showed higher plasma cytokine levels after surgery, but differences in alveolar cytokines were not detected. Although no patient required renal replacement therapy, acute kidney injury patients had higher incidence of cardiopulmonary complications and increased overall mortality. Plasma interleukin-6 at 6h was the most predictive cytokine of acute kidney injury (cut-off point at 4.89pg.mL^-1).

CONCLUSIONS

Increased postoperative plasma cytokine levels are associated with acute kidney injury after lung resection surgery in our study, which worsens the prognosis. Plasma interleukin-6 may be used as an early indicator for patients at risk of developing acute kidney injury after lung resection surgery.