Chung-Kan Peng

With-no-lysine Kinase 4 Mediates Alveolar Fluid Regulation in Hyperoxia-induced Lung Injury*

Objectives:To investigate mechanisms involved in the regulation of epithelial ion channels and alveolar fluid clearance in hyperoxia-induced lung injury. Design:Laboratory animal experiments. Setting:Animal care facility procedure room in a medical center. Subjects:Wild-type, STE20/SPS1-related proline/alanine-rich kinase knockout (SPAK–/–), and with-no-lysine kinase 4 knockin (WNK4D561A/+) mice. Interventions:Mice were exposed to room air or 95% hyperoxia for 60 hours. Measurements and Main Results:Exposure to hyperoxia for 60 hours increased the lung expression of with-no-lysine kinase 4 and led to STE20/SPS1-related proline/alanine-rich kinase and sodium-potassium-chloride cotransporter phosphorylation, which resulted in the suppression of alveolar fluid clearance and increase of lung edema. WNK4D561A/+ mice at the baseline presented an abundance of epithelium sodium channel and high levels of STE20/SPS1-related proline/alanine-rich kinase and sodium-potassium-chloride cotransporter phosphorylation. Compared with the wild-type group, hyperoxia caused greater epithelium sodium channel expression in WNK4D561A/+ mice, but no significant difference in STE20/SPS1-related proline/alanine-rich kinase and sodium-potassium-chloride cotransporter phosphorylation. The functional inactivation of sodium-potassium-chloride cotransporter by gene knockout in SPAK–/– mice yielded a lower severity of lung injury and longer animal survival, whereas constitutive expression of with-no-lysine kinase 4 exacerbated the hyperoxia-induced lung injury. Pharmacologic inhibition of sodium-potassium-chloride cotransporter by inhaled furosemide improved animal survival in WNK4D561A/+ mice. By contrast, inhibition of epithelium sodium channel exacerbated the hyperoxia-induced lung injury and animal death. Conclusions:With-no-lysine kinase 4 plays a crucial role in the regulation of epithelial ion channels and alveolar fluid clearance, mainly via phosphorylation and activation of STE20/SPS1-related proline/alanine-rich kinase and sodium-potassium-chloride cotransporter.

Predicting duration of mechanical ventilation in patients with carbon monoxide poisoning: a retrospective study.

PURPOSE Patients with severe carbon monoxide (CO) poisoning may develop acute respiratory failure, which needs endotracheal intubation and mechanical ventilation (MV). The objective of this study was to identify the predictors for duration of MV in patients with severe CO poisoning and acute respiratory failure. MATERIALS AND METHODS This is a retrospective observational study of 796 consecutive patients diagnosed with acute CO poisoning that presented to the emergency department. Patients who received MV were divided into 2 groups: the early extubation (EE) consisting of patients who were on MV for less than 72 hours and the nonearly extubation (NEE) consisting of patients who were on MV for more than 72 hours. Demographic and clinical data of the two groups were extracted for analysis. RESULTS The intubation rate of all CO-poisoned patients was 23.4%. A total of 168 patients were enrolled in this study. The main source of CO exposure was intentional CO poisoning by charcoal burning (137 patients). Positive toxicology screening result was found in 104 patients (61.9%). The EE group had 105 patients (62.5%). On arriving at the emergency department, high incidence of hypotension; high white blood cell count; and elevation of blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, creatine kinase, and troponin-I levels were statistically significant in the NEE group (P < .05). Positive toxicology screening result was statistically significant in the EE group (P < .05). In a multivariate analysis, elevation of troponin-I level was an independent factor for NEE (odds ratio, 1.305; 95% confidence interval, 1.024-1.663; P = .032). Positive toxicology screening result was an independent factor for EE (odds ratio, 0.222; 95% confidence interval, 0.101-0.489; P = .001). CONCLUSIONS A positive toxin screen predicts extubation within the first 72 hours for patients with severe CO poisoning and acute respiratory failure. On the other hand, elevation of initial troponin-I level is a predictor for a longer duration of MV.

Inhibition of Na-K-Cl cotransporter isoform 1 reduces lung injury induced by ischemia–reperfusion

Objectives: Ischemia–reperfusion acute lung injury is characterized by increased vascular permeability, lung edema, and neutrophil sequestration. Ischemia–reperfusion acute lung injury occurs in lung transplantation and other major surgical procedures. Effective regulation of alveolar fluid balance is critical for pulmonary edema. Sodium‐potassium‐chloride co‐transporter regulates alveolar fluid and is associated with inflammation. We hypothesized that sodium‐potassium‐chloride co‐transporter is important in ischemia–reperfusion acute lung injury. Bumetanide, a sodium‐potassium‐chloride co‐transporter inhibitor, is used to treat pulmonary edema clinically. We studied the effect of bumetanide in ischemia–reperfusion acute lung injury. Methods: Isolated perfusion of mouse lungs in situ was performed. The main pulmonary artery and left atrium were catheterized for lung perfusion and effluent collection for recirculation, respectively, with perfusate consisting of 1 mL blood and 9 mL physiologic solution. Ischemia–reperfusion was induced by 120 minutes of ischemia (no ventilation or perfusion) and reperfused for 60 minutes. Wild‐type, SPAK knockout (SPAK−/−), and WNK4 knockin (WNK4D561A/+) mice were divided into control, ischemia–reperfusion, and ischemia–reperfusion + bumetanide groups (n = 6 per group). Bumetanide was administered via perfusate during reperfusion. Measurements were taken of lung wet/dry weight, microvascular permeability, histopathology, cytokine concentrations, and activity of the nuclear factor‐&kgr;B pathway. Results: In wild‐type mice, ischemia–reperfusion caused lung edema (wet/dry weight 6.30 ± 0.36) and hyperpermeability (microvascular permeability, 0.29 ± 0.04), neutrophil sequestration (255.0 ± 55.8 cells/high‐power field), increased proinflammatory cytokines, and nuclear factor‐&kgr;B activation (1.33 ± 0.13). Acute lung injury was more severe in WNK4 mice with more lung edema, permeability, neutrophil sequestration, and nuclear factor‐&kgr;B activation. Severity of acute lung injury was attenuated in SPAK−/−mice. Bumetanide decreased pulmonary edema (wild‐type: wet/dry weight 5.05 ± 0.44, WNK4: wet/dry weight 5.13 ± 0.70), neutrophil sequestration (wild‐type: 151.7 ± 27.8 cells/high‐power field, WNK4: 135.3 ± 19.1 cells/high‐power field), permeability (wild‐type: 0.19 ± 0.01, WNK4: 0.21 ± 0.03), cytokines, and nuclear factor‐&kgr;B activation after ischemia–reperfusion. Conclusions: Functional reduction of sodium‐potassium‐chloride co‐transporter by genetic or pharmacologic treatment to inhibit sodium‐potassium‐chloride co‐transporter resulted in lower severity of acute lung injury induced by ischemia–reperfusion. Sodium‐potassium‐chloride co‐transporter may present a promising target for therapeutic interventions in a clinical setting.

Adjunctive hyperbaric oxygen therapy in severe burns: Experience in Taiwan Formosa Water Park dust explosion disaster

BACKGROUND Despite major advances in therapeutic strategies for the management of patients with severe burns, significant morbidity and mortality is observed. Hyperbaric oxygen therapy (HBOT) increases the supply of oxygen to burn areas. The aim of this study was to determine whether HBOT is effective in the treatment of major thermal burns. METHODS On June 27, 2015 in New Taipei, Taiwan, a mass casualty disaster occurred as fire erupted over a large crowd, injuring 499 people. Fifty-three victims (20 women and 33 men) were admitted to Tri-Service General Hospital. Thirty-eight patients underwent adjunctive HBOT (HBOT group), and 15 patients received routine burn therapy (control group). Serum procalcitonin (PCT) level, a sepsis biomarker, was measured until it reached normal levels (<0.5μg/L). The records of all patients from June 2015 to March 2016 were analyzed retrospectively. Outcome measures that were compared between the groups included the use of tracheostomy and hemodialysis, total body surface area (TBSA) and the number of skin graft operations, length of hospital stay, infection status, and mortality. RESULTS The mean age of the patients was 22.4 years, and the mean TBSA was 43%. All the patients survived and were discharged without requiring limb amputation or being permanently disabled. Patient characteristics did not differ significantly between the groups. PCT levels returned to normal significantly faster (p=0.007) in the HBOT group. CONCLUSION Multidisciplinary burn care combined with adjunctive HBOT improves sepsis control compared with standard treatment without HBOT. Prospective studies are required to define the role of HBOT in extensive burns.

Predicting poor outcome in patients with intentional carbon monoxide poisoning and acute respiratory failure: A retrospective study

Purpose: Intentional carbon monoxide (CO) poisoning has become the commonly used method of suicide in some Asian countries. The objective of this study was to identify the predictors that impact the outcome of intentional CO-poisoned patients with acute respiratory failure. Materials and Methods: This is a retrospective observational study of 796 consecutive patients diagnosed with acute CO poisoning that presented to the emergency department (ED). Patients who were CO poisoned with intentional exposure and acute respiratory failure were enrolled and divided into two groups. The poor outcome group consisted of in-hospital death, the presence of persistent neurological sequelae, and the presence of delayed neurologic sequelae. The good outcome group consisted of other enrolled patients. Demographic and clinical data of the two groups were extracted for analysis. Results: A total of 148 patients were enrolled in this study. Of the eligible subjects, 67.6% (100) were identified with positive toxicology screening results. On arriving ED, parameters associated with patients with a poor outcome included hypotension, myocardial injury, prolonged lag times from the first ED arrival to initiation of hyperbaric oxygen therapy, higher white blood cell count, and higher serum levels of blood urea nitrogen, creatine kinase, and troponin-I (P < 0.05). Positive toxicology screening result did not relate to the outcome. Multivariate analysis showed that the myocardial injury was an independent factor for poor outcome (odds ratio, 2.750; 95% confidence interval, 1.168-6.474; P = 0.021). Conclusions: Myocardial injury is an independent predictor of in-hospital death and neurologic sequelae in patients with intentional CO poisoning and acute respiratory failure.

Activated protein C attenuates ischemia-reperfusion-induced acute lung injury

ABSTRACT Ischemia-reperfusion (IR)-induced acute lung injury (ALI) is implicated in several clinical conditions, such as lung transplantation, acute pulmonary embolism after thrombolytic therapy, re-expansion of collapsed lung from pneumothorax, or pleural effusion, cardiopulmonary bypass, etc. Because mortality remains high despite advanced medical care, prevention and treatment are important clinical issues. Activated protein C (APC) manifests multiple activities with antithrombotic, profibrinolytic, and anti-inflammatory effects. We therefore conducted this study to determine the beneficial effects of APC in IR-induced ALI. IR-induced ALI was conducted in a rat model of isolated-perfused lung in situ. The animals were divided into the control group, IR group, and IR+APC group. There were six adult male Sprague–Dawley rats in each group. The IR caused significant pulmonary microvascular hyperpermeability, pulmonary edema and dysfuction, increased cytokines (tumor necrosis factor (TNF)-α, IL-17, CXCL-1), and neutrophils infiltration in lung tissues. Administration of APC significantly attenuated IR-induced ALI with improving microvascular permeability, pulmonary edema, pulmonary dysfunction, and suppression inflammatory response. The current study demonstrates the beneficial effects of APC in IR-induced ALI. This protective effect is possibly associated with the inhibition of TNF-α, IL-17A, CXCL1, and neutrophils infiltration in lung tissues. However, the current results were obtained in an animal model and it is still necessary to confirm these findings in human subjects. If we can demonstrate the benefits of APC to protect IR lung injury, we can postulate that APC is a potential therapeutic drug for lung preservation.

Surviving Sepsis Campaign guidelines for a diver with DCI: case report

Severe decompression illness (DCI) is an uncommon medical issue affecting divers and results mainly from rapid surfacing using inadequate decompression protocols. Massive gas embolism with central nervous system involvement often leads to a poor prognosis, with permanent residual neurologic defects. Moreover, DCI complicated with multiple organ dysfunction syndrome (MODS) is tremendously rare and difficult to cure, although hyperbaric oxygen (HBO2) therapy following the U.S. Navy Treatment Tables is a consensus. We report a case of severe DCI with profound shock and MODS after an initial treatment with HBO2 therapy using U.S. Navy Treatment Table 6A. Following the Surviving Sepsis Campaign Guidelines, low-dose hydrocortisone was administered. Although this treatment went against recommendation of the U.S. Navy Diving Manual, it resulted in a dramatic clinical improvement. After a second round of HBO2 treatments, the patient was discharged from hospital two weeks after the diving accident.

Inhibition of NKCC1 Modulates Alveolar Fluid Clearance and Inflammation in Ischemia-Reperfusion Lung Injury via TRAF6-Mediated Pathways

Background: The expression of Na-K-2Cl cotransporter 1 (NKCC1) in the alveolar epithelium is responsible for fluid homeostasis in acute lung injury (ALI). Increasing evidence suggests that NKCC1 is associated with inflammation in ALI. We hypothesized that inhibiting NKCC1 would attenuate ALI after ischemia-reperfusion (IR) by modulating pathways that are mediated by tumor necrosis-associated factor 6 (TRAF6). Methods: IR-ALI was induced by producing 30 min of ischemia followed by 90 min of reperfusion in situ in an isolated and perfused rat lung model. The rats were randomly allotted into four groups comprising two control groups and two IR groups with and without bumetanide. Alveolar fluid clearance (AFC) was measured for each group. Mouse alveolar MLE-12 cells were cultured in control and hypoxia-reoxygenation (HR) conditions with or without bumetanide. Flow cytometry and transwell monolayer permeability assay were carried out for each group. Results: Bumetanide attenuated the activation of p-NKCC1 and lung edema after IR. In the HR model, bumetanide decreased the cellular volume and increased the transwell permeability. In contrast, bumetanide increased the expression of epithelial sodium channel (ENaC) via p38 mitogen-activated protein kinase (p38 MAPK), which attenuated the reduction of AFC after IR. Bumetanide also modulated lung inflammation via nuclear factor-κB (NF-κB). TRAF6, which is upstream of p38 MAPK and NF-κB, was attenuated by bumetanide after IR and HR. Conclusions: Inhibition of NKCC1 by bumetanide reciprocally modulated epithelial p38 MAPK and NF-κB via TRAF6 in IR-ALI. This interaction attenuated the reduction of AFC via upregulating ENaC expression and reduced lung inflammation.

Bumetanide attenuates acute lung injury by suppressing macrophage activation

Graphical abstract Figure. No Caption available. Abstract Bumetanide is a potent loop diuretic that acts as an inhibitor of sodium‐potassium‐chloride cotransporter 2 (NKCC2) and its isoform NKCC1. Although the expression of NKCC2 is limited to the kidney, NKCC1 is widely expressed in various cells, where it participates in a variety of physiological functions including ion transport, alveolar fluid secretion, and cell volume regulation. We investigated the role of NKCC1 in modulation of host immunity. Lipopolysaccharide (LPS) stimulated the expression and phosphorylation of NKCC1 in RAW264.7 cells in vitro and activated these cells to produce inflammatory cytokines. Enlarging the cell volume in a low‐osmotic microenvironment amplified the LPS‐induced inflammatory responses and phagocytosis activity of RAW264.7 cells. Pretreatment with the NKCC1 inhibitor bumetanide attenuated LPS‐induced activation of inflammatory cells and cell volume‐related function. Mice treated with an intratracheal bumetanide spray showed greater resistance to LPS‐induced tissue inflammation and acute lung injury in vivo. Our studies suggest that NKCC1 plays a unique role as an amplifier of LPS‐induced macrophage functions and that NKCC1 might be a novel target for treating sepsis‐related acute respiratory distress syndrome.

Dried salted plum consumption ameliorates hyperbaric oxygen therapy-induced otalgia severity at the first chamber session: a prospective randomized controlled study

PURPOSE One of the most common complications of hyperbaric oxygen (HBO₂) therapy is middle ear barotrauma (MEB), occasionally causing otalgia. The objective of this study was to evaluate the effect of dried salted plum consumption on MEB and otalgia associated with HBO₂ therapy. MATERIALS AND METHODS Patients undergoing the first chamber session of HBO₂ therapy were included in the present prospective randomized controlled trial. The Valsalva maneuver was administered to all patients before HBO₂. The patients were randomly divided into two groups: one that ate a dried salted plum during HBO₂ treatment and the other that did not. An otoscopic examination was performed after HBO₂ therapy. The MEB was graded according to Teed scores. The degree of otalgia was recorded using the Visual Analog Scale (VAS). RESULTS Ninety patients were enrolled. The overall incidence of MEB (Teed score grade 1~4) was 39.6% (21 of 53) for patients administered a dried salted plum versus 37.8% (14 of 37) for the control group (P=1.000). The incidence of mild MEB (Teed score grade 1~2) and severe MEB (Teed score Grade 3~4) between the two groups was not significantly different. Otalgia was present in 5.7% (3 of 53) of patients administered a dried salted plum versus 18.9% (7 of 37) for the control group (P=.085). No patients administered a dried salted plum had a VAS score ≥4 for otalgia versus 10.8% (4 of 37) for the control group (P=.026). CONCLUSIONS Dried salted plum consumption does not decrease the incidence of MEB, but may ameliorate the severity of first chamber session HBO₂-induced otalgia.