ARDS and sepsis--definitions and new therapy

COVID-19-Associated Acute Brain Dysfunction Related to Sepsis

In global term, as of November 30, 2020, over 30 million people has been infected by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and more than 10,000,000 of them died of acute organ failure. Our reviews have shown that coronavirus disease 2019 (COVID-19) patients with pneumonia and acute respiratory distress syndrome (ARDS) have life-threatening acute brain dysfunction (ABD), ranging from altered mental status/delirium to stupor/coma. Altered mental status/delirium was the most common manifestation of ABD caused by severe COVID-19. The prevalence of altered mental status and/or delirium was up to 66-79.5%, and prevalence of coma was 10%. The most common clinical type of COVID-19-associated ABD was COVID-19-associated acute stroke including ischemic and hemorrhagic stroke (n > 350 cases), followed by COVID-19-associated encephalopathy (n > 200 cases), and COVID-19-associated central nervous system (CNS) infection (n > 70 cases). According to the Sepsis-3 criteria, we confess that severe COVID-19-associated ABD with ARDS and altered mental status is related to sepsis. Moreover, we also review the diagnosis and treatment of COVID-19-associated ABD with sepsis. In view of the fact that COVID-19 is at the peak of epidemic worldwide, we hope that this review will provide evidence of COVID-19 sepsis threating to the brain dysunction. Thus, recognizing the COVID-19-associated ABD related to sepsis is very important for early empirical combination therapy to survive severe COVID-19.

Characterization, lung targeting profile and therapeutic efficiency of dipyridamole liposomes

The acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury (ALI). Its pathogenesis is closely linked with reactive oxygen species (ROS). Antioxidation has been considered as an efficient treatment. Besides, liposomes are widely investigated as potential drug carriers due to their ability to protect and carry drug molecules to the target organ such as the lung. The present study was undertaken to investigate whether dipyridamole (DIP), delivered as a liposomal preparation, can ameliorate the lipopolysaccharides (LPS)-induced ALI due to the changes of its biodistribution. First, the liposomes entrapping DIP were prepared by film hydration for treating ARDS. Subsequently, the characterizations including entrapment efficiency, size, span and micrograph of DIP liposomes were measured. The concentration change of DIP in tissues and plasma of mice after intravenous administration of DIP injection and DIP liposomes was determined by RP-HPLC and calculated to lung targeting parameters. To prove the therapeutic efficiency, the effects of DIP liposomes on LPS-induced ALI were studied compared with DIP injection. The results showed DIP liposomes have the relative high entrapment efficiency and satisfying particle size. Compared with DIP injection, the liposomes increased the accumulation of DIP in the lung on a vast scale. Furthermore, DIP liposomes alleviated the ALI induced by LPS significantly. All of the results suggested that DIP liposomes have the potential efficacy in treating ALI/ARDS due to their obvious lung targeting.

San-Huang-Xie-Xin-Tang attenuates inflammatory responses in lipopolysaccharide-exposed rat lungs

In this study, the potential anti-inflammatory effect of San-Huang-Xie-Xin-Tang (SHXT) and its main component baicalin on LPS-induced lung injury were investigated and compared to the profile of dexamethasone (DEXA) in a pre-clinical animal model. Post-treatment with SHXT (75 mg/kg), baicalin (1.5 mg/kg) and DEXA (0.5 mg/kg), significantly inhibited LPS-induced hypotension, lung edema and acute survival rates. Western blotting analysis results indicated that all of them significantly inhibited LPS-induced iNOS, TGF-beta, p38MAPK, and ICAM-1 expressions in the lung tissues. Results from ELISA analysis showed that SHXT, baicalin and DEXA all decreased plasma levels of IL-1beta, TNF-alpha, and MCP-1 caused by LPS. Based on these findings, SHXT and baicalin decreased plasma concentrations of IL-1beta, TNF-alpha, MCP-1, and expressions of TGF-beta, ICAM-1, phosphorylated p38 MAPK, and iNOS, which were associated with lung injury and lethality. These evidences indicated that SHXT and baicalin showed strong anti-inflammatory activity, similar to that observed for DEXA, and therefore implicated that herbal SHXT might be therapeutically useful for the treatment of endotoxic lung injury.

Prophylaxis against lipopolysaccharide-induced acute lung injury by alpha-tocopherol liposomes

OBJECTIVE

To investigate whether intravenously administered liposomal alpha-tocopherol can protect the lung from the injurious action of Escherichia coli lipopolysaccharide (LPS).

DESIGN

Prospective, randomized animal study.

SETTING

Government research laboratory.

SUBJECTS

Twenty adult male Sprague-Dawley rats.

INTERVENTIONS

Animals were intravenously pretreated with alpha-tocopherol liposomes (20 mg alpha-tocopherol/kg body weight), plain liposomes, or saline. Twenty-four hours later, pretreated animals were challenged with an intravenous injection of LPS (E. coli 0111:B4, 1 mg/kg body weight), and killed 2 hrs after LPS challenge.

MEASUREMENTS AND MAIN RESULTS

Challenge of saline-pretreated animals with LPS resulted in lung injuries as evidenced by an increase in wet lung weight and a reduction in pulmonary angiotensin converting enzyme (25%) and alkaline phosphatase (28%), injury markers of lung endothelial and epithelial type II cells, respectively. Also, LPS administration resulted in an increase in pulmonary myeloperoxidase and protease activities, indicative of a neutrophilic inflammatory response. Pretreatment of animals with liposomal alpha-tocopherol significantly attenuated the LPS-induced edematous lung weight response, and reduced the extent of injuries to the pulmonary endothelial and epithelial cells, demonstrated by a significantly smaller reduction in the corresponding enzyme marker activities.

CONCLUSION

These results suggest that augmentation of the pulmonary antioxidant status can ameliorate LPS-induced lung injuries mediated by oxidative stress mechanisms.

The pulmonary uptake of intravenously administered liposomal alpha-tocopherol is augmented in acute lung injury

The present study was carried out to investigate whether the intravenous administration of liposomal alpha-tocopherol can result in a significant localization of the antioxidant in the injured lung. Male Sprague-Dawley rats were injected with paraquat dichloride (20 mg/kg, ip.) and 4, 24 or 48 h later, they were given an intravenous injection of a liposomal alpha-tocopherol preparation (20 mg alpha-tocopherol in 128 mumoles liposomal lipid/kg) labelled with [14C]dipalmitoylphosphatidylcholine (DPPC) and [3H]alpha-tocopherol. Animals were killed and their lungs removed for analysis 24 h after liposomal treatment. To demonstrate whether the extent of uptake of radioactive alpha-tocopherol liposomes was directly related to the extent of residual lung injury, additional groups of animals were also injected with higher doses (30 and 40 mg/kg body weight) of paraquat dichloride and 48 h later, were treated with liposomal alpha-tocopherol; animals were then killed 24 h after liposomal alpha-tocopherol treatment. The intraperitoneal injection of paraquat dichloride resulted in time- and dose-dependent decreases in angiotensin converting enzyme and alkaline phosphatase activities suggesting that the toxicant injures both the capillary endothelial cells and alveolar type II epithelial cells, respectively. The recovery of intravenously administered radioactive alpha-tocopherol in the lungs of saline-treated animals was found to be about 2% of the initial dose 24 h post-liposomal treatment. However, in paraquat-treated animals, there was an increased localization of the labelled alpha-tocopherol to the lung, resulting in a difference of pulmonary delivery by as much as 2-3 fold compared to that in a normal lung. The 3H/14C ratio, representing the recovery of [3H]alpha-tocopherol and [14C]liposomes, was practically constant and there was a linear relationship between the measurable lung injury index and the corresponding recovery of radiolabelled alpha-tocopherol in the lung. Our results appear to suggest that the residual pulmonary injury augments the delivery of liposomal alpha-tocopherol to the lung.