Postoperative anion gap associates with short- and long-term mortality after cardiac surgery: A large-scale cohort study.

Objective: To investigate whether postoperative anion gap (AG) is associated with short- and long-term mortality in patients following cardiac surgery. Materials and methods: We conducted a retrospective cohort study of adults who underwent cardiac surgery from the Medical Information Mart for Intensive Care - III database. The generalized additive model (GAM), logistic regression, and Cox regression were performed to assess the correlations between AG levels and in-hospital, 90-day, and 4-year mortality. Linear regression was used to evaluate the associations between AG and length of stay (LOS). Results: Totally, 6,410 subjects were enrolled in this study and classified into tertiles based on the initial AG levels. The GAM indicated a positive association between initial AG and in-hospital mortality after adjusting for potential confounders. Multivariate logistic analysis revealed that the risk of in-hospital mortality was higher among patients in tertile 2 (OR 2.05, 95% CI 1.11-3.76, P = 0.021) and tertile 3 (OR 4.51, 95% CI 2.57-7.91, P < 0.001) compared with those in tertile 1. For 90-day and 4-year mortality, multivariate Cox regression found similar associations between AG tertiles and mortality. The LOS in ICU and hospital also increased as AG tertiles increased. The E-value indicated robustness to unmeasured confounders. Conclusion: This study found a positive association between postoperative AG levels and short- and long-term mortality among patients after cardiac surgery. This relationship warrants further research.

Phosphorylation at Ser 727 Increases STAT3 Interaction with PKCε Regulating Neuron-Glia Crosstalk via IL-6-Mediated Hyperalgesia In Vivo and In Vitro.

METHODS: A rat hyperalgesia model was induced using an intraplantar injection of Freund's complete adjuvant (FCA) or an intrathecal injection of IL-6. Mechanical allodynia was evaluated using von Frey filament tests after intrathecal injections of T-5224 (c-Fos/AP-1 inhibitor), minocycline (Mino, a specific microglia inhibitor), L-2-aminoadipic acid (LAA, an astroglial toxin), PKCε inhibitor peptide, APTSTAT3-9R (STAT3 inhibitor), or anti-IL-6 antibody. The c-Fos, GFAP, Iba-1, PKCε, STAT3, pSTAT3Tyr705 and pSTAT3Ser727, and IL-6 expression at the spinal cord level was assessed by Western blot analysis. The interactive effects of PKCε and STAT3 were determined using immunofluorescence staining and immunoprecipitation in vivo and in vitro. Interleukin-6 promoter activity was examined using luciferase assays. RESULTS: T-5224, Mino, and LAA attenuated FCA- or IL-6-mediated inflammatory pain, with a decrease in c-Fos, GFAP, Iba-1, PKCε, and IL-6 expression. PKCε inhibitor peptide and APTSTAT3-9R reversed FCA-induced nociceptive behavior, while decreasing pSTAT3Ser727, IL-6, c-Fos, GFAP, and Iba-1 expression and PKCε and STAT3 coexpression. Interleukin-6 promoter activity increased in the presence of PKCε and STAT3. The interaction with PKCε increased on phosphorylating STAT3 at Ser727 but not at Tyr705. CONCLUSION: STAT3 phosphorylation at Ser 727 and the interaction with PKCε contribute to hyperalgesia via the IL-6-mediated signaling pathway, thus regulating neuron-glia crosstalk during inflammatory pain.

Allopurinol ameliorates liver injury in type 1 diabetic rats through activating Nrf2.

Hyperglycemia-induced oxidative stress plays important roles in the development of non-alcoholic fatty liver disease (NAFLD), which is a common complication in diabetic patients. The Nrf2-Keap1 pathway is important for cell antioxidant protection, while its role in exogenous antioxidant mediated protection against NAFLD is unclear. We thus, postulated that antioxidant treatment with allopurinol (ALP) may attenuate diabetic liver injury and explored the underlying mechanisms. Control (C) and streptozotocin (STZ)-induced diabetes rats (D) were untreated or treated with ALP for 4 weeks starting at 1 week after diabetes induction. Serum levels of alanine aminotransferase (ALT) and aspartate transaminase (AST), production of lipid peroxidation product malondialdehyde (MDA), and serum superoxide dismutase (SOD) were detected. Liver protein expressions of cleaved-caspase 3, IL-1ß, nuclear factor-erythroid-2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1), P62, Kelch-like ECH-associated protein 1 (Keap1), and LC3 were analyzed. In vitro, cultured rat normal hepatocytes BRL-3A were grouped to normal glucose (5.5 mM, NG) or high glucose (25 mM, HG) and treated with or without allopurinol (100 µM) for 48 h. Rats in the D group demonstrated liver injury evidenced as increased serum levels of ALT and AST. Diabetes increased apoptotic cell death, enhanced liver protein expressions of cleaved-caspase 3 and IL-1ß with concomitantly increased production of MDA while serum SOD content was significantly reduced (all P < 0.05 vs C). In the meantime, protein levels of Nrf2, HO-1, and P62 were reduced while Keap1 and LC3 were increased in the untreated D group as compared to control (P < 0.05 vs C). And all the above alterations were significantly attenuated by ALP. Similar to our findings obtained from in vivo study, we got the same results in in vitro experiments. It is concluded that ALP activates the Nrf2/p62 pathway to ameliorate oxidative stress and liver injury in diabetic rats.

Allopurinol reduces oxidative stress and activates Nrf2/p62 to attenuate diabetic cardiomyopathy in rats.

Allopurinol (ALP) attenuates oxidative stress and diabetic cardiomyopathy (DCM), but the mechanism is unclear. Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) following the disassociation with its repressor Keap1 under oxidative stress can maintain inner redox homeostasis and attenuate DCM with concomitant attenuation of autophagy. We postulated that ALP treatment may activate Nrf2 to mitigate autophagy over-activation and consequently attenuate DCM. Streptozotocin-induced type 1 diabetic rats were untreated or treated with ALP (100 mg/kg/d) for 4 weeks and terminated after heart function measurements by echocardiography and pressure-volume conductance system. Cardiomyocyte H9C2 cells infected with Nrf2 siRNA or not were incubated with high glucose (HG, 25 mmol/L) concomitantly with ALP treatment. Cell viability, lactate dehydrogenase, 15-F2t-Isoprostane and superoxide dismutase (SOD) were measured with colorimetric enzyme-linked immunosorbent assays. ROS, apoptosis, was assessed by dihydroethidium staining and TUNEL, respectively. The Western blot and qRT-PCR were used to assess protein and mRNA variations. Diabetic rats showed significant reductions in heart rate (HR), left ventricular eject fraction (LVEF), stroke work (SW) and cardiac output (CO), left ventricular end-systolic volume (LVVs) as compared to non-diabetic control and ALP improved or normalized HR, LVEF, SW, CO and LVVs in diabetic rats (all P < .05). Hearts of diabetic rats displayed excessive oxidative stress manifested as increased levels of 15-F2t-Isoprostane and superoxide anion production, increased apoptotic cell death and cardiomyocytes autophagy that were concomitant with reduced expressions of Nrf2, heme oxygenase-1 (HO-1) and Keap1. ALP reverted all the above-mentioned diabetes-induced biochemical changes except that it did not affect the levels of Keap1. In vitro, ALP increased Nrf2 and reduced the hyperglycaemia-induced increases of H9C2 cardiomyocyte hypertrophy, oxidative stress, apoptosis and autophagy, and enhanced cellular viability. Nrf2 gene silence cancelled these protective effects of ALP in H9C2 cells. Activation of Nrf2 subsequent to the suppression of Keap1 and the mitigation of autophagy over-activation may represent major mechanisms whereby ALP attenuates DCM.

[Effect of dexmedetomidine on inflammatory factors level and cognitive function after femoral head replacement in elderly patients].

OBJECTIVE: To analyze the effect of dexmedetomidine on the inflammatory factors level and cognitive function after femoral head replacement in elderly patients. METHODS: From January 2016 to December 2017, 60 elderly patients(more than 60 years old, and Grade I to II of ASA) treated with femoral head replacement were divided into three groups, and 20 in each group. All patients received midazolam, fentanyl, etomidate, cisatracurium anesthesia induction and sevoflurane inhalation anesthesia maintenance. The patients in group B and group C were first given 1.0 µg·kg⁻¹ of dexmedetomidine 10 minutes during the operation. The maintenance volume was 0.3 µg·kg⁻¹·h⁻¹ of dexmedetomidine(in group B) and 0.6 µg·kg⁻¹·h⁻¹ of dexmedetomidine(in group C) by pumping. The same amount of saline was given to the patients in group A in the same way. The time of extubation, wakefulness and recovery, the simple intelligent mental state score (MMSE), the incidence of postoperative cognitive dysfunction (POCD) and the levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and S100ß protein expression in the 3 groups were compared. RESULTS: There were significant differences in the time of spontaneous breathing recovery, eye opening tome and the time of extubation, as well as the dosage of propofol among the three groups(P<0.05). On the 1st, 3rd and 7th day after operation, there was a significant difference in MMSE score of group B and group C compared with that of group A(P<0.05), and MMSE score in group C was significantly higher than that of group B(P<0.05). The incidence of POCD was 0.0% (0/20) and the incidence of adverse reactions was 30%(6/20) in group C, but those were 25% (5/20) and 0.0% (0/20) in group A and 5% (1/20) and 10% (2/20) respectively in group B. The difference was statistically significant (P<0.05). Before induction of anesthesia, there was no significant difference in the levels of IL-6, IL-10 and S100ß protein among the three groups(P>0.05); but one hour after the operation, the levels of IL-6 IL-10 and S100ß protein in group B and group C was statistically different from those in group A(P<0.05). The IL-6 and S100ß protein in group C were significantly lower than those in group B (P<0.05), and IL-10 was significantly higher than that in group B (P<0.05). CONCLUSIONS: For elderly patients operated for femoral head replacement, dexmedetomidine can reduce the level of inflammatory factors level and propofol consumption, and the incidence of postoperative POCD is low, indicating a dose dependence of dexmedetomidine. But it is necessary to choose the right dose according to the patient's condition.

Tramadol attenuates the sensitivity of glioblastoma to temozolomide through the suppression of Cx43­mediated gap junction intercellular communication.

Analgesics and antineoplastic drugs are often used concurrently for cancer patients. Our previous study reported that gap junctions composed of connexin32 (Cx32) was implicated in the effect of analgesics on cisplatin cytotoxicity. However, the effect of analgesic on the most widely expressed connexin (Cx), connexin43 (Cx43), and whether such effect mediates the influence on chemotherapeutic efficiency remain unknown. By manipulation of Cx43 expression or gap junction function, we found that there were gap junction-dependent and independent effect of Cx43 on temozolomide (TMZ) sensitivity in U87 glioblastoma cells. Studies on survival and apoptosis showed widely used analgesic tramadol significantly reduced TMZ-induced cytotoxicity in control and negative control cells but not shCx43-transfected cells. Proliferation assay demonstrated tramadol suppressed TMZ-induced cytotoxicity only on high density (with gap junction formation) but not on low density (without gap junction formation). Tramadol inhibited dye-coupling through gap junctions between U87 cells. Tramadol treatment for 72 h did not alter Cx43 expression, but decreased Cx43 phosphorylation accompanied with reduced p-ERK and p-JNK. Our results indicated that long-term treatment with tramadol reduced TMZ cytotoxicity in U87 cells by suppressing Cx43-composed gap junctions, suggesting identification and usage of antinociceptive drugs which do not downregulate connexin activity should have beneficial therapeutic consequences.

Adipose-derived mesenchymal stem cells therapy for acute kidney injury induced by ischemia-reperfusion in a rat model.

Acute kidney injury (AKI) represents a group of complicated syndromes with a high mortality rate. The administration of adipose-derived mesenchymal stem cells (ADMSCs) has been tested as a possible treatment method for AKI. The long-term evaluation of AKI induced by ischemia/reperfusion (IR) and the probable renal protection of ADMSCs are limited. In this study we have established a rat AKI model induced by IR and investigated the possible protective effects of ADMSCs. Adult Sprague-Dawley (SD) rats were divided into three groups (n = 6/each group). The MOCK group was as the normal control. Rats in the IR-AKI and IR-AKI+ADMSCs groups were subjected to IR injury by clamping both renal pedicles for 40 minutes. Rats in the MOCK and IR-AKI groups were injected with PBS via the tail vein as negative treatment controls. Rats in the IR-AKI+ADMSCs group received ADMSCs therapy (2 × 106 cells were injected into the rats via the tail vein). We found that ADMSC transplantation restored the pathologic morphology induced by IR-AKI to normal compared with the MOCK group, suggesting the reparative function of ADMSCs in kidney tissues. Compared with IR-induced AKI alone, ADMSC treatment significantly decreased the number of apoptotic cells, the level of total urinary protein and serum creatinine, the expression of pro-inflammatory cytokines (IL-6, TNF-α, IL-1ß, IFN-γ, TNF-α, IFN-γ, and TGF-ß), and the inflammation-associated proteins (HGF and SDF1), but increased the expression of the anti-inflammatory cytokine, IL-10, and the anti-apoptotic regulator, Bcl-2. Our data have indicated that ADMSC transplantation may protect against IR-induced AKI by anti-apoptotic and anti-inflammatory effects.

Simvastatin protects Sertoli cells against cisplatin cytotoxicity through enhanced gap junction intercellular communication.

Cisplatin, an important chemotherapeutic agent against testicular germ cell cancer, induces testicular toxicity on Leydig and Sertoli cells, leading to serious side-effects such as azoospermia and infertility. In a previous study, it was found that simvastatin enhanced the sensitivity of Leydig tumor cells to chemotherapeutic toxicity through the enhancement of gap junction functions. In the present study, the effect of simvastatin on the sensitivity of normal Sertoli cells to cisplatin and the role of gap junctions in such effects was investigated. The results showed that, simvastatin attenuated cisplatin toxicity only when cells exhibited high-density culture where gap junctional formation was possible. When gap junction function was decreased by the gap junction inhibitor or by siRNA targeting connexin 43, the protective effect of simvastatin to cisplatin toxicity was substantially attenuated. Simvastatin also enhanced gap junction functions between Sertoli cells. This effect was mediated by the reduction of PKC-mediated connexin phosphorylation, thereby increasing connexin 43 membrane localization. Thus, simvastatin-induced enhancement of gap junction­mediated intercellular communication attenuated cisplatin toxicity on Sertoli cells. This result indicated that enhancement of gap junction function by simvastatin may have bilateral beneficial effects on cisplatin­based chemotherapy, enhancing cisplatin killing on cancer while ameliorating the reproduction toxicity.

[Expression of connexin 43 in spinal cord dorsal horn of rats with acute incisional pain].

OBJECTIVE: To examine the effect of acute incisional pain on the expression of connexin 43 in rat spinal cord dorsal horn. METHODS: Eighty rats were assigned into control group without any treatment and incisional pain group with incision surgery. For paw incisions, a 1-cm longitudinal incision was made through the skin and fascia of the plantar aspect of the right hind paw. After surgery, the 50% paw withdrawal threshold (PWT) was assessed in response to a tactile stimulus with calibrated von Frey monofilaments at 1, 2, 4 and 24 h, respectively. The spinal cord dorsal horn of rats was isolated at 1, 2, and 4 h after the surgery to assess the expression of connexin 43 using Western blotting and immunofluorescence assay. RESULTS: The 50% PWT of the rats was significantly decreased after the incision surgery, and this decrement was the most obvious at 2 and 4 h. Western blotting and immunofluorescence assay showed that the expression of connexin 43 in the spinal cord dorsal horn was significantly increased in rats receiving the surgery especially at 2 and 4 h after the surgery. CONCLUSION: Incision surgery induces an significant increase in connexin 43 expression in rat spinal cord dorsal horn, suggestting an potential role of connexin43 in postoperative incisional pain.

In vivo transfection of nuclear factor κB decoy protects pulmonary function against acute lung contusion in rabbits.

BACKGROUND: The transcription factor nuclear factor κB (NF-κB) regulates the expression of numerous proinflammatory factors that may exacerbate the response to acute injury. We investigated the effect of an inhibitory NF-κB decoy oligodeoxynucleotide on proinflammatory factor expression and pulmonary function after acute lung contusion in rabbits. METHODS: Thirty-minutes after acute lung contusion, the NF-κB decoy or a scrambled control oligodeoxynucleotide was injected via the jugular vein. Blood samples were collected for blood gas analysis and plasma tumor necrosis factor α, interleukin 1ß (IL-1ß), IL-13, and IL-10 were measured by enzyme-linked immunosorbent assay at 1, 2, 3, and 4 hours after contusion. In addition, NF-κB protein expression in lung tissue was detected by Western blot analysis. RESULTS: The blood PO2 decreased immediately after lung contusion, whereas PAO2 increased significantly, indicative of disrupted respiratory function. Respiratory function improved after sense NF-κB decoy injection but not after injection of the inactive scrambled form. Injection of NF-κB decoy resulted in significant inhibition of NF-κB protein expression in lung tissue and a reduction in the serum concentrations of proinflammatory cytokines tumor necrosis factor α and IL-1ß compared with those of control rabbits injected with the scrambled decoy. In contrast, serum levels of the anti-inflammatory cytokines IL-10 and IL-13 increased after decoy injection compared with those of control animals and rabbits injected with the scrambled decoy. CONCLUSION: The sense NF-κB decoy protected respiratory function and reduced serum proinflammatory factor secretion after acute lung contusion. Inhibition of NF-κB may allow for preservation of pulmonary function for patients with acute lung injury.