Impact of Steroids on the Inflammatory Response after Ischemic Acute Kidney Injury in Rats

Treating Critically Ill Patients Experiencing SARS-CoV-2 Severe Infection with Ig-M and Ig-A Enriched Ig-G Infusion

SARS-CoV-2 in patients who need intensive care unit (ICU) is associated with a mortality rate ranging from 10 to 40–45%, with an increase in morbidity and mortality in presence of sepsis. We hypothesized that IgM and IgA enriched immunoglobulin G may support the sepsis-related phase improving patient outcome. We conducted a retrospective case–control study on 47 consecutive patients admitted to our ICU. At the time of admission, patients received anticoagulants (heparin sodium) together with the standard supportive treatment. We decided to add IgM and IgA enriched immunoglobulin G to the standard therapy. Patients receiving IgM and IgA enriched immunoglobulin G were compared with patients with similar baseline characteristics and treatment, receiving only standard therapy. The mortality resulted significantly higher in patients treated with standard therapy only (56.5 vs. 37.5%, p < 0.01) and, at day 7, the probability of dying was 3 times higher in this group. Variable life adjustment display (VLAD) was 2.4 and −2.2 (in terms of lives saved in relation with those expected and derived from Simplified Acute Physiology Score II) in the treated and not treated group, respectively. The treatment based on IgM and IgA enriched immunoglobulin G infusion seems to give an advantage on survival in SARS-CoV-2 severe infection.

Phillyrin Relieves Lipopolysaccharide-Induced AKI by Protecting Against Glycocalyx Damage and Inhibiting Inflammatory Responses

Damage to the integrity of heparin sulfate (HS) in the endothelial glycocalyx is an important factor of glomerular filtration barrier dysfunction, which is the basic pathological feature of acute kidney injury (AKI). AKI is a common clinical critical illness with few drugs options offering effective treatment. Phillyrin (Phil), the main pharmacological component of Forsythia suspensa, possesses a wide range of pharmacological activities. However, the effects of Phil on lipopolysaccharide (LPS)-induced AKI have yet to be reported. The aim of the present study is to analyze the effects of Phil on HS damage and inflammatory signaling pathways in LPS-induced AKI. Results revealed that Phil reduces pathological changes and improves renal function in LPS-induced AKI. Further analysis indicated that Phil effectively protects against glycocalyx HS degradation in LPS-stimulated EA.hy926 cells in vitro and LPS-induced AKI mice in vivo. The protective effect of Phil on HS damage may be associated with the isolate's ability to suppress the production of reactive oxygen species, and decrease expression levels of cathepsin L and heparanase in vitro and in vivo. In addition, ELISA and Western blot results revealed that Phil inhibits the activation of the NF-κB and MAPK signaling pathways and decreases the levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α) in LPS-induced ARDS mice. In general, protection against endothelial glycocalyx HS damage and inhibition of inflammatory responses by Phil may be used as treatment targets for LPS-induced AKI.

LncRNA XIST serves as a ceRNA to regulate the expression of ASF1A, BRWD1M, and PFKFB2 in kidney transplant acute kidney injury via sponging hsa-miR-212-3p and hsa-miR-122-5p

We aimed to identify potential mechanism associated with acute kidney injury (AKI) after kidney transplantation. The dataset GSE53771, which contained 18 zero-hour (ZERO group) and 18 selected post-transplant (POST group) biopsy samples from 18 kidney allografts (8 AKI and 10 controls) was downloaded from GEO database. Differentially expressed miRNAs (DEMIs) were screened using limma package, and bidirectional hierarchical clustering of the DEMIs was performed using the pheatmap package. Target genes of DEMIs were predicted by miRWalk 2.0, miRNA-target genes networks were presented using Cytoscape, protein-protein interaction (PPI) networks were constructed by STRING (version:10.0) database, and competing endogenous RNAs (ceRNA) regulating network were constructed using Cytoscape. In ZERO and POST groups, a total of 4 and 24 differentially expressed miRNAs were obtained in AKI samples compared with control, respectively. Specifically, 71 lncRNAs were obtained to interact with five miRNAs (hsa-miR-215-5p, hsa-miR-192-5p, hsa-miR-422a, hsa-miR-212-3p and hsa-miR-122-5p). Histone chaperone ASF1A (ASF1A) and bromodomain and WD repeat-containing protein 1(BRWD1) were targeted by hsa-miR-212-3p in PPI network. In ceRNA network, lncRNA XIST could interact with four miRNAs (hsa-miR-212-3p, hsa-miR-122-5p, hsa-miR-215-5p, and hsa-miR-192-5p). LncRNA XIST might serve as a ceRNA to sponge hsa-miR-212-3p to regulate the development of AKI via altering the expression of ASF1A/BRWD1. Furthermore, lncRNA XIST could also interact with hsa-miR-122-5p to modulate the expression of PFKFB2 in thyroid hormone signaling pathway and AMPK signaling pathway. LncRNA XIST can serve as a ceRNA to sponge hsa-miR-212-3p and hsa-miR-122-5p to regulate AKI progression via modulating the expression of ASF1A, BRWD1, and PFKFB2.[Figure: see text].

Impact of different emulsifiers on biocompatibility and inflammatory potential of Perfluorohexyloctane (F6H8) emulsions for new intravenous drug delivery systems

Background

Emulsions on the basis of Perfluorohexyloctane (F6H8), a semifluorinated alkane (SFA), have shown to dissolve and transport highly lipophilic compounds. It is unknown how F6H8-containing emulsions (F6H8-cEM) interact with compartment blood, the reticuloendothelial system (RES), or influence injured organs in vivo. The current study was conducted to investigate the in vitro biocompatibility of F6H8-cEM and their drug delivery properties. Afterward, an in vivo study was performed as a proof-of-concept study in a rat model of acute kidney injury (AKI), which focused on the potential influence of F6H8-cEM on inflammation in an injured organ.

Methods

Two different F6H8-cEM were stabilized by the emulsifying agents Poloxamer 188 (Pluronic^® F68) or lecithin (S75). The two resulting emulsions F6H8-Pluronic or F6H8-lecithin were tested in vitro for the potential modulation of acute inflammation via whole blood assay, FACS, and ELISA. Antioxidant capacity and drug delivery properties were measured with an oxidation assay. Secondly, AKI was induced in the rats, which were treated with the F6H8-lecithin emulsion. Renal function and inflammation were assessed.

Results

Both F6H8-cEM were phagocytized by monocytes and both dose-dependently affected apoptosis (Annexin V binding) in monocytes. TNF-α expression increased dose-dependency for F6H8-Pluronic emulsion but not for F6H8-lecithin in a whole blood assay. Both F6H8-cEM were able to carry α-tocopherol as a model drug. Animals with AKI treated with the F6H8-lecithin emulsion showed a significantly better renal function and less infiltration of inflammatory cells in renal tissue compared to the control, while inflammatory markers in renal tissue, except HO-1, were not affected by F6H8-lecithin.

Conclusions

Pluronic^® F68 does not seem suitable as a biocompatible surfactant for F6H8-cEM. The injured kidney was not negatively influenced by the F6H8-lecithin emulsion. Lecithin-stabilized F6H8-cEM could be tested for preclinical studies as a carrier system for lipophilic agents.

Connexin32 plays a crucial role in ROS-mediated endoplasmic reticulum stress apoptosis signaling pathway in ischemia reperfusion-induced acute kidney injury

BACKGROUND

Ischemia-reperfusion (I/R)-induced acute kidney injury (AKI) not only prolongs the length of hospital stay, but also seriously affects the patient's survival rate. Although our previous investigation has verified that reactive oxygen species (ROS) transferred through gap junction composed of connexin32 (Cx32) contributed to AKI, its underlying mechanisms were not fully understood and viable preventive or therapeutic regimens were still lacking. Among various mechanisms involved in organs I/R-induced injuries, endoplasmic reticulum stress (ERS)-related apoptosis is currently considered to be an important participant. Thus, in present study, we focused on the underlying mechanisms of I/R-induced AKI, and postulated that Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI.

METHODS

We established renal I/R models with Cx32+/+ and Cx32-/- mice, which underwent double kidneys clamping and recanalization. ROS scavenger (N-acetylcysteine, NAC) and ERS inhibitors (4-phenyl butyric acid, 4-PBA, and tauroursodeoxycholic acid, TUDCA) were used to decrease the content of ROS and attenuate ERS activation, respectively.

RESULTS

Renal damage was progressively exacerbated in a time-dependent manner at the reperfusion stage, that was consistent with the alternation of ERS activation, including glucose regulated protein 78 (BiP/GRP78), X box-binding protein1, and C/EBP homologous protein expression. TUDCA or 4-PBA application attenuated I/R-induced ERS activation and protected against renal tubular epithelial cells apoptosis and renal damage. Cx32 deficiency decreased ROS generation and distribution between the neighboring cells, which attenuated I/R-induced ERS activation, and improved cell apoptosis and renal damage.

CONCLUSION

Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI. Cx32 deficiency, ROS elimination, and ERS inhibition all could protect against I/R-induced AKI.

Pentoxifylline and Methylprednisolone Additively Alleviate Kidney Failure and Prolong Survival of Rats after Renal Warm Ischemia-Reperfusion

Renal ischemia-reperfusion injury (IRI) induces local inflammation leading to kidney damage. Since pentoxifylline (PTX) and steroids have distinct immunomodulatory properties, we aimed to evaluate for the first time their combined use in IRI-induced acute kidney injury (AKI) and chronic kidney disease (CKD) in rats. In two experiments, PTX (100 mg/kg body weight subcutaneously) was administered 90 min prior to renal IRI or/and methylprednisolone (MP; 100 mg/kg body weight intramuscularly) was infused 60 min after reperfusion of a solitary kidney (AKI model: 45 min ischemia, 48 male Sprague-Dawley rats) or one kidney with excision of contralateral kidney 2 weeks later (CKD model: 90 min ischemia, 38 rats). Saline was infused in place of PTX or/and MP depending on the group. Renal function (diuresis, serum creatinine, creatinine clearance, sodium and potassium excretion, and urine protein/creatinine) was assessed at 48 h and 120 h post-IRI (AKI model) or 4, 16 and 24 weeks after IRI, along with survival analysis (CKD model). More evidently at early stages of AKI or CKD, treated animals showed higher glomerular filtration and diminished tubular loss of electrolytes, more so with PTX + MP than PTX or MP (serum creatinine (μmol/L) at 48 h of AKI: 60.9 ± 19.1 vs. 131.1 ± 94.4 vs. 233.4 ± 137.0, respectively, vs. 451.5 ± 114.4 in controls, all p < 0.05; and at 4 weeks of CKD: 89.0 ± 31.9 vs. 118.1 ± 64.5 vs. 156.9 ± 72.6, respectively, vs. 222.9 ± 91.4 in controls, p < 0.05 for PTX or PTX + MP vs. controls and PTX + MP vs. MP). Survival was better by >2-fold with PTX + MP (89%) vs. controls (40%; p < 0.05). PTX + MP largely protect from IRI-induced AKI and CKD and subsequent mortality in rats. This calls for clinical investigations, especially in kidney transplantation.