BackgroundRenal ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury and a frequent occurrence in critically ill patients. Renal IRI releases proinflammatory cytokines within the kidney that induce crosstalk between the kidney and other organ systems. Atrial natriuretic peptide (ANP) has anti-inflammatory as well as natriuretic effects and serves important functions as a regulator of blood pressure, fluid homeostasis, and inflammation. The objective of the present study was to elucidate whether ANP post-treatment attenuates kidney-lung-heart crosstalk in a rat model of renal IRI.MethodsIn experiment I, a rat model of unilateral renal IRI with mechanical ventilation was prepared by clamping the left renal pedicle for 30 min. Five minutes after clamping, saline or ANP (0.2 μg/kg/min) was infused. The hemodynamics, arterial blood gases, and plasma concentrations of lactate and potassium were measured at baseline and at 1, 2, and 3 h after declamping. The mRNA expression and localization of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in the kidney, lung, and heart were examined. In experiment II, a rat model of bilateral renal IRI without mechanical ventilation was prepared by clamping bilateral renal pedicles for 30 min. Thirty minutes after clamping, lactated Ringer's (LR) solution or ANP (0.2 μg/kg/min) was infused. Plasma concentrations of TNF-α, IL-6, and IL-1β were determined at baseline and at 3 h after declamping.ResultsIn unilateral IRI rats with mechanical ventilation, ANP inhibited the following changes induced by IRI: metabolic acidosis; pulmonary edema; increases in lactate, creatinine, and potassium; and increases in the mRNA expression of TNF-α, IL-1β, and IL-6 in the kidney and lung and IL-1β and IL-6 in the heart. It also attenuated the histological localization of TNF-α, IL-6, and nuclear factor (NF)-κB in the kidney and lung. In bilateral IRI rats without mechanical ventilation, ANP attenuated the IRI-induced increases of the plasma concentrations of potassium, IL-1β, and IL-6.ConclusionsRenal IRI induced injury in remote organs including the lung and the contralateral kidney. ANP post-treatment ameliorated injuries in these organs by direct tissue protective effect and anti-inflammatory effects, which potentially inhibited inter-organ crosstalk.

Background. This study aimed to determine the perioperative change in serum double-strand DNA (dsDNA) as a marker potentially reflecting neutrophil extracellular trap concentration in samples from patients undergoing cardiac surgery and to analyze a relationship between serum dsDNA concentrations and perioperative renal dysfunction. Methods. Serum dsDNA concentrations in samples that were collected during a previously conducted, prospective, multicenter, observational study were measured. Eighty patients undergoing elective cardiac surgery were studied. Serum samples were collected at baseline, immediately after surgery, and the day after surgery (POD-1). Results. Serum dsDNA concentration was significantly increased from baseline (median, 398 ng/mL [interquartile range, 372–475 ng/mL]) to immediately after surgery (median, 540 ng/mL [437–682 ng/mL], p < 0.001), and they were reduced by POD-1 (median, 323 ng/mL [256–436 ng/mL]). The difference in serum creatinine concentration between baseline and POD-1 was correlated with dsDNA concentration on POD-1 (r s = 0.61, p < 0.001). Conclusions. In patients undergoing cardiac surgery, serum dsDNA concentration is elevated postoperatively. Prolonged elevation in dsDNA concentration is correlated with perioperative renal dysfunction. Further large-scale studies are needed to determine the relationship between serum concentration of circulating dsDNA and perioperative renal dysfunction.

BackgroundDexmedetomidine (DEX) could have an analgesic effect on pain transmission through the modulation of brain-derived neurotrophic factor (BDNF). In addition, KCC2-induced shift in neuronal Cl− homeostasis is crucial for postsynaptic inhibition mediated by GABAA receptors. Accumulating evidence shows that nerve injury, peripheral inflammation and stress activate the spinal BDNF/TrkB signal, which results in the downregulation of KCC2 transport and expression, eventually leads to GAGAergic disinhibition and hyperalgesia. The aim of this experiment was to explore the interaction between DEX and KCC2 at a molecular level in rats in the persistent postsurgical pain (PPSP).MethodsPPSP in rats was evoked by the skin/muscle incision and retraction (SMIR). Mechanical hypersensitivity was assessed with the Dynamic Plantar Aesthesiometer. Western blot and immunofluorescence assay were used to assess the expressions of related proteins.ResultsIn the first part of our experiment, the results revealed that the BDNF/TrkB-KCC2 signal plays a critical role in the development of SMIR-evoked PPSP; the second part showed that intraperitoneal administrations of 40 µg/kg DEX at 15 min presurgery and 1 to 3 days post-surgery significantly attenuated SMIR-evoked PPSP. Simultaneously, SMIR-induced KCC2 downregulation was partly reversed, which coincided with the inhibition of the BDNF/TrkB signal in the spinal dorsal horn. Moreover, intrathecal administrations of KCC2 inhibitor VU0240551 significantly reduced the analgesic effect of DEX on SMIR-evoked PPSP.ConclusionThe results of our study indicated that DEX attenuated PPSP by restoring KCC2 function through reducing BDNF/TrkB signal in the spinal dorsal horn in rats, which provides a new insight into the treatment of chronic pain in clinical postsurgical pain management.

Review question / Objective: To clarify which one has a different predominance of Th1 and Th2 immune responses in malignant and tuberculous pleural effusions. We did a meta-analysis of the results published previously to assess the levels of Th1/Th2 cytokines in two types of pleural effusion and evaluated its ability to distinguish TPE from MPE. Condition being studied: Malignant and tuberculous pleural effusions are the two most common types of exudative pleural effusions, both of which can be seen with the typical accumulation of lymphocytes. Immune responses mediated by either the Th1 or Th2 subset dominate, depending on different types of pleural effusion. Thus, we performed a meta-analysis of all available studies to quantitatively evaluate the levels of Th1/Th2 cytokine profiles in TPE and MPE, as well as to assess the potential diagnostic value of these cytokines in discriminating TPE from MPE.