Renal tubular epithelial cells injury induced by mannitol and its potential mechanism

The U-shaped association between serum osmolality and 28-day mortality in patients with sepsis: a retrospective cohort study

BACKGROUND

Sepsis is a recognized global health challenge that places a considerable disease burden on countries. Although there has been some progress in the study of sepsis, the mortality rate of sepsis remains high. The relationship between serum osmolality and the prognosis of patients with sepsis is unclear.

METHOD

Patients with sepsis who met the criteria in the Medical Information Mart for Intensive Care IV database were included in the study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were determined using multivariable Cox regression. The relationship between serum osmolality and the 28-day mortality risk in patients with sepsis was investigated using curve fitting, and inflection points were calculated.

RESULTS

A total of 13,219 patients with sepsis were enrolled in the study; the mean age was 65.1 years, 56.9 % were male, and the 28-day mortality rate was 18.8 %. After adjusting for covariates, the risk of 28-day mortality was elevated by 99% (HR 1.99, 95%CI 1.74-2.28) in the highest quintile of serum osmolality (Q5 >303.21) and by 59% (HR 1.59, 95%CI 1.39-1.83) in the lowest quintile (Q1 ≤285.80), as compared to the reference quintile (Q3 291.38-296.29). The results of the curve fitting showed a U-shaped relationship between serum osmolality and the risk of 28-day mortality, with an inflection point of 286.9 mmol/L.

CONCLUSION

There is a U-shaped relationship between serum osmolality and the 28-day mortality risk in patients with sepsis. Higher or lower serum osmolality is associated with an increased risk of mortality in patients with sepsis. Patients with sepsis have a lower risk of mortality when their osmolality is 285.80-296.29 mmol/L.

Quercetin protects cardiomyoblasts against hypertonic cytotoxicity by abolishing intracellular Ca2+ elevations and mitochondrial depolarisation

BACKGROUND AND AIM

Osmotic changes represent a burden for the body and their limitation would be beneficial. We hypothesized that ubiquitous natural compounds could guard against cytotoxic effects of osmotic stress. We evaluated the anti-hypertonic mechanism of quercetin and 2,3-dehydrosilybin in H9c2 cells in vitro.

EXPERIMENTAL PROCEDURE

Protective effect of both compounds was determined by neutral red assay, cell apoptosis was estimated by measuring caspase-3 activity and verified by western blot and annexin V assay. Phosphorylation level of selected proteins was also detected. Mitochondrial membrane potential was evaluated using dye JC-1. Ca2+ signals were evaluated using genetically encoded fluorescent Ca2+ biosensor GCaMP7f. Formation of reactive oxygen species was measured using an oxidant-sensing probe dihydrofluorescein diacetate.

KEY RESULTS

Quercetin protected H9c2 cells against hypertonic stress-induced cell death. We observed a significant increase in intracellular Ca2+ levels ([Ca2+]cyto) when cells originally placed in a hypertonic solution were returned to a normotonic environment. Quercetin was found to prevent this increase in [Ca2+]cyto and also the depolarization of mitochondrial membrane potential.

CONCLUSIONS AND IMPLICATIONS

Quercetin, but not 2,3-dehydrosilybin, reduced adverse effects of osmotic stress mainly by dampening the elevation of [Ca2+]cyto and mitochondrial Ca2+ overload. This may consequently prevent MPTP pore opening and activation of apoptosis.

Prospective assessment of the impact of intraoperative diuretics in kidney transplant recipient surgery

BACKGROUND

The use of intraoperative diuretics, such as furosemide or mannitol, during kidney transplantation has been suggested to reduce the rate of delayed graft function (DGF). The evidence base for this is sparse, however, and there is substantial variation in practice. We sought to evaluate whether the use of intraoperative diuretics during kidney transplantation translated into a reduction in DGF.

METHODS

We conducted a cohort study evaluating the use of furosemide or mannitol given intraoperatively before kidney reperfusion compared with control (no diuretic). Adult patients receiving a kidney transplant for end-stage renal disease were allocated to receive furosemide, mannitol, or no diuretic. The primary outcome was DGF; secondary outcomes were graft function at 30 days and perioperative changes in potassium levels. Descriptive and comparative statistics were used where appropriate.

RESULTS

A total of 162 patients who received a kidney transplant from a deceased donor (either donation after neurologic determination of death or donation after circulatory death) were included over a 2-year period, with no significant between-group differences. There was no significant difference in DGF rates between the furosemide, mannitol, and control groups. When the furosemide and mannitol groups were pooled (any diuretic use) and compared with the control group, however, there was a significant improvement in the odds that patients would be free of DGF (odds ratio 2.10, 95% confidence interval 1.06-4.16, 26% v. 44%, p = 0.03). There were no significant differences noted in any secondary outcomes.

CONCLUSION

This study suggests the use of an intraoperative diuretic (furosemide or mannitol) may result in a reduction in DGF in patients undergoing kidney transplantation. Further study in the form of a randomized controlled trial is warranted.

Exploring the possible mechanism(s) underlying the nephroprotective effect of Zhenwu Decoction in diabetic kidney disease: An integrated analysis

BACKGROUND

Diabetic kidney disease (DKD) is one of the major chronic microvascular complications of diabetes and the main cause of end-stage renal failure. Zhenwu Decoction (ZWD), an ancient classic herbal formula in Chinese medicine, has been clinically used for the treatment of kidney disease in China for many years. However, there is currently limited research investigating the application of ZWD in the treatment of DKD and the underlying chemical and biochemical mechanisms involved. Therefore, in the present study, we aimed to identify active components in ZWD and unravel the possible mechanism(s) of action for ZWD in treating DKD.

METHODS

The protective effect of ZWD against DKD was evaluated utilizing an in vitro model of diabetic renal proximal tubulopathy. The major chemical components from ZWD were identified by LC-MS/MS. Drug targets were predicted by submitting the SMILES (Simplified Molecular Input Line Entry System) of the compounds to SEA (Similarity Ensemble Approach) search server and SwissTargetPrediction. The differentially expressed genes (DEGs) of the disease were collected and integrated from GeneCards. The constructions of "Compounds-potential targets interaction" (CTI) network and Protein-Protein Interaction (PPI) network, as well as topology analysis were conducted by Cytoscape. Gene Ontology (GO) enrichment and Metacore pathway enrichment analysis were also performed. Lastly, molecular docking and experimental studies were adopted to validate the core target and identify an active component(s) of ZWD.

RESULTS

We demonstrated that the ZWD extract could significantly rescue the palmitic acid (PA) and high glucose-induced apoptotic cell death in HK-2 cells, and the cytoprotection was accompanied by decreases in the extent of reactive oxygen species (ROS) production, mitochondrial membrane depolarization and ATP depletion. Fifty-seven compounds in the aqueous extract of ZWD were identified by LC-MS. The results of PPI analysis showed that top hub genes involved epidermal growth factor receptor (EGFR), Signal Transducer and Activator of Transcription 3 (STAT3), Serine/Threonine Kinase 1 (AKT1), Vascular Endothelial Growth Factor A (VEGFA) and Fibroblast Growth Factor 2 (FGF2). Pathway enrichment analysis revealed the involvement of S1P1 receptor signaling and EGFR pathways. The results of molecular docking analysis showed that albiflorin has a high binding affinity to EGFR. Albiflorin could also exert protective effects in an HK-2 cell model of DKD, which may be related to the inhibition of the high glucose/high lipid-induced EGFR and Akt phosphorylation.

CONCLUSION

ZWD has been shown to be effective in ameliorating cell death in an experimental model of DKD. The beneficial effect of ZWD against DKD was associated with the interactions between the active ingredients and the hub genes, such as EGFR, STAT3, AKT1, and VEGF-A. Albiflorin may be one of the active components responsible for the nephroprotective effect in ZWD.

Development of a Spray-Dried Formulation of Peptide-DNA Nanoparticles into a Dry Powder for Pulmonary Delivery Using Factorial Design

BACKGROUND

Gene therapy via pulmonary delivery holds the potential to treat various lung pathologies. To date, spray drying has been the most promising method to produce inhalable powders. The present study determined the parameters required to spray dry nanoparticles (NPs) that contain the delivery peptide, termed RALA (N-WEARLARALARALARHLARALARALRACEA-C), complexed with plasmid DNA into a dry powder form designed for inhalation.

METHODS

The spray drying process was optimised using full factorial design with 19 randomly ordered experiments based on the combination of four parameters and three centre points per block. Specifically, mannitol concentration, inlet temperature, spray rate, and spray frequency were varied to observe their effects on process yield, moisture content, a median of particle size distribution, Z-average, zeta potential, encapsulation efficiency of DNA NPs, and DNA recovery. The impact of mannitol concentration was also examined on the spray-dried NPs and evaluated via biological functionality in vitro.

RESULTS

The results demonstrated that mannitol concentration was the strongest variable impacting all responses apart from encapsulation efficiency. All measured responses demonstrated a strong dependency on the experimental variables. Furthermore, spray drying with the optimal variables in combination with a low mannitol concentration (1% and 3%, w/v) produced functional RALA/pDNA NPs.

CONCLUSION

The optimal parameters have been determined to spray dry RALA/pDNA NPs into an dry powder with excellent biological functionality, which have the potential to be used for gene therapy applications via pulmonary delivery.

Gut Microbiota as a Source of Uremic Toxins

Uremic retention solutes are the compounds that accumulate in the blood when kidney excretory function is impaired. Some of these compounds are toxic at high concentrations and are usually known as “uremic toxins”. The cumulative detrimental effect of uremic toxins results in numerous health problems and eventually mortality during acute or chronic uremia, especially in end-stage renal disease. More than 100 different solutes increase during uremia; however, the exact origin for most of them is still debatable. There are three main sources for such compounds: exogenous ones are consumed with food, whereas endogenous ones are produced by the host metabolism or by symbiotic microbiota metabolism. In this article, we identify uremic retention solutes presumably of gut microbiota origin. We used database analysis to obtain data on the enzymatic reactions in bacteria and human organisms that potentially yield uremic retention solutes and hence to determine what toxins could be synthesized in bacteria residing in the human gut. We selected biochemical pathways resulting in uremic retention solutes synthesis related to specific bacterial strains and revealed links between toxin concentration in uremia and the proportion of different bacteria species which can synthesize the toxin. The detected bacterial species essential for the synthesis of uremic retention solutes were then verified using the Human Microbiome Project database. Moreover, we defined the relative abundance of human toxin-generating enzymes as well as the possibility of the synthesis of a particular toxin by the human metabolism. Our study presents a novel bioinformatics approach for the elucidation of the origin of both uremic retention solutes and uremic toxins and for searching for the most likely human microbiome producers of toxins that can be targeted and used for the therapy of adverse consequences of uremia.

Hydration with Mannitol and Dextrose May Promote Cisplatin-Induced Nephrotoxicity: Test of Five Protocols of Hydration during Cisplatin Therapy in Rat Models

Backgrounds

Cisplatin (CP) still is a novel choice for solid tumor therapy, but it is accompanied with the side effect of nephrotoxicity. Hydration may reduce the risk of CP-induced nephrotoxicity, while the issue is still challenging. In this study, five types of hydration protocols including saline, mannitol, dextrose saline, saline plus furosemide, and saline plus mannitol were examined in both sexes of rats during CP therapy.

Methods

Seventy-six male and female Wistar rats in 14 groups of experiments were subjected to CP therapy, and five types of hydration protocols were implemented, and the induced nephrotoxicity was evaluated via biochemical markers, kidney function parameters, and pathology investigation.

Results

Male and female rats had different responses to hydration protocol types. The higher mortality rate was seen in female rats that received mannitol or dextrose hydration types. In addition, the serum levels of blood urea nitrogen (BUN) and creatinine (Cr) and sodium excretion fraction (ENa%) increased and the clearance of Cr (ClCr) decreased significantly (P < 0.05) in female rats hydrated with saline plus furosemide or mannitol plus saline-treated groups. The worsened condition in male rats is observed in the mannitol hydration group with a significant decrease of ClCr and significant increase of serum BUN and Cr and ENa% (P < 0.05). The higher kidney tissue damage score (KTDS) in the mentioned groups verified the findings.

Conclusion

Hydration with mannitol or dextrose promotes the risk of nephrotoxicity during CP therapy with more intensity on the female.

Potentially Detrimental Effects of Hyperosmolality in Patients Treated for Traumatic Brain Injury

Hyperosmotic therapy is commonly used to treat intracranial hypertension in traumatic brain injury patients. Unfortunately, hyperosmolality also affects other organs. An increase in plasma osmolality may impair kidney, cardiac, and immune function, and increase blood-brain barrier permeability. These effects are related not only to the type of hyperosmotic agents, but also to the level of hyperosmolality. The commonly recommended osmolality of 320 mOsm/kg H2O seems to be the maximum level, although an increase in plasma osmolality above 310 mOsm/kg H2O may already induce cardiac and immune system disorders. The present review focuses on the adverse effects of hyperosmolality on the function of various organs.

Chemical profiling of Houttuynia cordata Thunb. by UPLC-Q-TOF-MS and analysis of its antioxidant activity in C2C12 cells

Houttuynia cordata Thunb. ("Yu-Xing-Cao"), a traditional Chinese medicinal herb, has long been used to treat various diseases. However, detailed information regarding the chemical constituents of H. cordata aqueous extract is lacking, and the molecular basis of its beneficial effects on muscle is unknown. To investigate these points, in this study, we used ultra-performance liquid chromatography coupled with quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) in positive and negative ion modes to profile and identify the major constituents of H. cordata water extract. A total of 63 peaks were identified based on mass and fragmentation characteristics, including 29 organic acids and their glycosides, 17 flavonoids, 7 volatiles, 4 pyrimidine and purine derivatives, 2 alkaloids, 2 amino acids, 1 isovanillin, and 1 coumarin. The total flavonoid and polyphenol contents of the extract were 4.77 and 139.15 mg/mL, respectively, by ultraviolet spectrophotometry. The cytoprotective activity of H. cordata aqueous extract was evaluated using C2C12 cells treated with tumor necrosis factor (TNF)-α to induce oxidative challenge. The TNF-α induced decrease in cell viability was reversed by treatment for 48 h with the extract; moreover, superoxide dismutase activity was increased while reactive oxygen species level was decreased. These results provide molecular-level evidence for the antioxidant effect of H. cordata extract and highlight its therapeutic potential for the treatment of muscle injury or diseases caused by oxidative stress.

Acute Kidney Injury in Traumatic Brain Injury Patients: Results From the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury Study

OBJECTIVES

Acute kidney injury is frequent in polytrauma patients, and it is associated with increased mortality and extended hospital length of stay. However, the specific prevalence of acute kidney injury after traumatic brain injury is less recognized. The present study aims to describe the occurrence rate, risk factors, timing, and association with outcome of acute kidney injury in a large cohort of traumatic brain injury patients.

DESIGN

The Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury is a multicenter, prospective observational, longitudinal, cohort study.

SETTING

Sixty-five ICUs across Europe.

PATIENTS

For the present study, we selected 4,509 traumatic brain injury patients with an ICU length of stay greater than 72 hours and with at least two serum creatinine values during the first 7 days of ICU stay.

MEASUREMENTS AND MAIN RESULTS

We classified acute kidney injury in three stages according to the Kidney Disease Improving Global Outcome criteria: acute kidney injury stage 1 equals to serum creatinine × 1.5-1.9 times from baseline or an increase greater than or equal to 0.3 mg/dL in 48 hours; acute kidney injury stage 2 equals to serum creatinine × 2-2.9 times baseline; acute kidney injury stage 3 equals to serum creatinine × three times baseline or greater than or equal to 4 mg/dL or need for renal replacement therapy. Standard reporting techniques were used to report incidences. A multivariable Cox regression analysis was performed to model the cause-specific hazard of acute kidney injury and its association with the long-term outcome. We included a total of 1,262 patients. The occurrence rate of acute kidney injury during the first week was as follows: acute kidney injury stage 1 equals to 8% (n = 100), acute kidney injury stage 2 equals to 1% (n = 14), and acute kidney injury stage 3 equals to 3% (n = 36). Acute kidney injury occurred early after ICU admission, with a median of 2 days (interquartile range 1-4 d). Renal history (hazard ratio = 2.48; 95% CI, 1.39-4.43; p = 0.002), insulin-dependent diabetes (hazard ratio = 2.52; 95% CI, 1.22-5.197; p = 0.012), hypernatremia (hazard ratio = 1.88; 95% CI, 1.31-2.71; p = 0.001), and osmotic therapy administration (hazard ratio = 2.08; 95% CI, 1.45-2.99; p < 0.001) were significantly associated with the risk of developing acute kidney injury. Acute kidney injury was also associated with an increased ICU length of stay and with a higher probability of 6 months unfavorable Extended Glasgow Outcome Scale and mortality.

CONCLUSIONS

Acute kidney injury after traumatic brain injury is an early phenomenon, affecting about one in 10 patients. Its occurrence negatively impacts mortality and neurologic outcome at 6 months. Osmotic therapy use during ICU stay could be a modifiable risk factor.

Acute kidney injury in patients with malignant middle cerebral artery infarction undergoing hyperosmolar therapy with mannitol

PURPOSE

To assess the kidney safety profile of mannitol in patients with malignant middle cerebral artery (MCA) infarction.

MATERIAL AND METHODS

We studied consecutive patients with malignant MCA infarction (01/2008-01/2018). Malignant MCA infarction was defined according to DESTINY criteria. We compared clinical endpoints including acute kidney injury (AKI; according to Kidney Disease: Improving Global Outcomes [KDIGO]) and dialysis between patients with and without mannitol. Multivariable model was built to explore predictor variables of AKI and in-hospital death.

RESULTS

Overall, 219 patients with malignant MCA infarction were included. Mannitol was administered in 93/219 (42.5%) patients with an average dosage of 650 g (250-950 g). Patients treated with mannitol more frequently suffered from AKI (39.8% vs. 11.9%; p < 0.001) and required hemodialysis (7.5% vs. 0.8%; p = 0.01) than patients without mannitol. At discharge, more patients in the mannitol group had persistent AKI than control patients (23.7% vs. 6.4%, p < 0.001). In multivariable model, mannitol emerged as independent predictor of AKI (OR 5.02, 95%CI 2.36-10.69; p < 0.001).

CONCLUSIONS

Acute kidney injury appears to be a frequent complication of hyperosmolar therapy with mannitol in patients with malignant MCA infarction. Given the lack of evidence supporting effectiveness of mannitol in these patients, its routine use should be carefully considered.

Examining Mannitol Use in Kidney Cancer Surgery: A Cautionary Tale of Extrapolated Surgical Data

Mannitol for renal protection during partial nephrectomy is common but unsupported by evidence from clinical trials. The impact of mannitol on renal physiology includes both beneficial and harmful effects. Current understanding of renal ischemia reperfusion injury suggests potentially targetable processes that have a lower potential risk.

Hydrogen sulfide inhibits Ca2+-induced mitochondrial permeability transition pore opening in type-1 diabetes

Hydrogen sulfide (H2S) attenuates N-methyl-d-aspartate receptor-R1 (NMDA-R1) and mitigates diabetic renal damage; however, the molecular mechanism is not well known. Whereas NMDA-R1 facilitates Ca2+ permeability, H2S is known to inhibit L-type Ca2+ channel. High Ca2+ activates cyclophilin D (CypD), a gatekeeper protein of mitochondrial permeability transition pore (MPTP), thus facilitating molecular exchange between matrix and cytoplasm causing oxidative outburst and cell death. We tested the hypothesis of whether NMDA-R1 mediates Ca2+ influx causing CypD activation and MPTP opening leading to oxidative stress and renal injury in diabetes. We also tested whether H2S treatment blocks Ca2+ channel and thus inhibits CypD and MPTP opening to prevent renal damage. C57BL/6J and Akita (C57BL/6J-Ins2Akita) mice were treated without or with H2S donor GYY4137 (0.25 mg·kg-1·day-1 ip) for 8 wk. In vitro studies were performed using mouse glomerular endothelial cells. Results indicated that low levels of H2S and increased expression of NMDA-R1 in diabetes induced Ca2+ permeability, which was ameliorated by H2S treatment. We observed cytosolic Ca2+ influx in hyperglycemic (HG) condition along with mitochondrial-CypD activation, increased MPTP opening, and oxidative outburst, which were mitigated with H2S treatment. Renal injury biomarker KIM-1 was upregulated in HG conditions and normalized following H2S treatment. Inhibition of NMDA-R1 by pharmacological blocker MK-801 revealed similar results. We conclude that NMDA-R1-mediated Ca2+ influx in diabetes induces MPTP opening via CypD activation leading to increased oxidative stress and renal injury, and H2S protects diabetic kidney from injury by blocking mitochondrial Ca2+ permeability through NMDA-R1 pathway.