Soluble tumor necrosis factor receptor prevents post-pump syndrome

GV-971 attenuates the progression of neuromyelitis optica in murine models and reverses alterations in gut microbiota and associated peripheral abnormalities

AIMS

Growing evidence suggests that an imbalanced gut microbiota composition plays a crucial role in the development of neuromyelitis optica spectrum disorders (NMOSD), an inflammatory demyelinating disease primarily affecting the optic nerves and central nervous system (CNS). In light of this, we explored the potential therapeutic benefits of GV-971 in NMOSD. GV-971 is a drug used for treating mild-to-moderate Alzheimer's disease, which targets the gut-brain axis and reduces neuroinflammation.

METHODS

To evaluate GV-971's effects, we employed the experimental autoimmune encephalomyelitis (EAE) mouse model to establish NMOSD animal models. This was achieved by injecting NMO-IgG into aged mice (11 months old) or using NMO-IgG along with complement injection and microbubble-enhanced low-frequency ultrasound (MELFUS) techniques in young mice (7 weeks old). We assessed the impact of GV-971 on incidence rate, clinical scores, body weight, and survival, with methylprednisolone serving as a positive control. In NMOSD models of young mice, we analyzed spinal cord samples through H&E staining, immunohistochemistry, and Luxol Fast Blue staining. Fecal samples collected at different time points underwent 16S rRNA gene sequencing, while plasma samples were analyzed using cytokine array and untargeted metabolomics analysis.

RESULTS

Our findings indicated that GV-971 significantly reduced the incidence of NMOSD, alleviated symptoms, and prolonged survival in NMOSD mouse models. The NMOSD model exhibited substantial neuroinflammation and injury, accompanied by imbalances in gut microbiota, peripheral inflammation, and metabolic disorders, suggesting a potentially vicious cycle that accelerates disease pathogenesis. Notably, GV-971 effectively reduces neuroinflammation and injury, and restores gut microbiota composition, as well as ameliorates peripheral inflammation and metabolic disorders.

CONCLUSIONS

GV-971 attenuates the progression of NMOSD in murine models and reduces neuroinflammation and injury, likely through its effects on remodeling gut microbiota and peripheral inflammation and metabolic disorders.

Tryptophan decreases the intensity of lipopolysaccharide-induced acute lung injury in a rat model

Sepsis is a severe clinical condition that is a result of the cellular and biochemical response to infection. The present study evaluated the therapeutic potential of tryptophan against lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. Rats were grouped into sham, control (ALI), and ALI + 1, 25, and 50 mg/kg body weight L-tryptophan. Supplementation with 1, 25, and 50 mg/kg L-tryptophan reduced the total protein content by 4.9%, 33.4%, and 64.5%; the levels of neutrophils (12.5%, 31.8%, and 65.1%), lymphocytes (15.1%, 41.7%, and 63.3%), total cells (12.6%, 42.4%, and 65.7%); lipid peroxidation (9.4%, 28.4%, and 68.7%); myeloperoxidase levels (12.1%, 33.4%, and 68.2%); migration inhibitory factor (12.7%, 39.5%, and 68.2%), interleukin (IL)-8 (5.5%, 46.8%, and 78.5%), tumor necrosis factor (TNF)-α (10.8%, 39.8%, and 72.2%), respectively. Supplementation with 1, 25, and 50 mg/kg L-tryptophan reduced mRNA expression of TNF-α (4.5%, 21.8%, and 41.8%), IL-1β (5.2%, 17.9%, and 46.2%); and the protein expression of TNF-α (2.8%, 15.2%, and 35.7%) and IL-1β (5.2%, 15.6%, and 28.6%), respectively. It also reduced glutathione (to near normal levels), neutrophilic infiltration and edema, and the wet/dry ratio of lung tissue. It significantly increased catalase, superoxide dismutase, glutathione peroxidase levels, as well as the partial pressure of oxygen (PaO₂) by 21.9%, 52.8%, and 87.4%, respectively. Altogether, our results suggest that supplementation with L-tryptophan has a strong protective effect against LPS-induced ALI.

Mechanistic Evaluation of the Protective Effect of Carnosine on Acute Lung Injury in Sepsis Rats

This study analyzes the sepsis healing therapeutic potential of carnosine against experimentally sepsis-induced male albino rats. Carnosine in 2 different doses, 25 mg/kg and 50 mg/kg, were administered for 30 consecutive days. At the end of the treatment, lipid peroxidation, catalase, superoxide dismutase, glutathione peroxidase and myeloperoxidase activities were measured. Lungs weight and total protein content were determined in the bronchoalveolar fluid (BALF). Cytokines such as macrophage inhibitory factor (MIF), interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-α) were determined in the BALF. In addition, the histopathological analysis was also carried out to understand the effect of carnosine in the cellular architecture. Carnosine treatment significantly renormalized the lipid peroxidation and other antioxidant enzymes. IL-β, TNF-α, and MIF were found to be reduced after carnosine treatment. After carnosine treatment, the intensity of sepsis was significantly reduced evidenced by histopathological analysis. In western blot analysis, carnosine treatment causes the upregulation of IκBα together with the downregulation of the expressions of p65 and p-IKKα/β (Ser 180/Ser 181).

Efficacy and Therapeutic Potential of Curcumin Against Sepsis-Induced Chronic Lung Injury in Male Albino Rats

The present study investigates curcumin effect against sepsis-induced chronic lung injury (CLI) of male albino rats. Rats were grouped into four groups such rats undergoing a sham cecal ligature puncture (CLP), rats undergoing CLP, rats undergoing CLP and treated with saline and rats undergoing CLP and treated with curcumin (100 mg/kg bwt). After 45 days of treatment, bronchoalveolar fluid (BALF), blood and lung tissues were collected from the each animal. The total protein content, wet and dry (W/D) weight of lung tissues and some inflammatory cells in the BALF were measured. Histopathological analysis was carried out to investigate the alteration of the cellular architecture of lung tissues. Lipid peroxidation malondialdehyde (MDA), superoxide dismutase (SOD) and myeloperoxidase (MPO) levels were determined. Cytokines such as interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-a) and macrophage inhibitory factor (MIF) were measured in the BALF. Curcumin administration significantly reduced CLP-induced inflammation and pulmonary edema. Curcumin treatment is significantly reduced MPO activity, and inflammatory cell accumulation in the BALF and also protein level, MDA, SOD, and W/D ratio were significantly reduced in the lung tissues. Also, curcumin reduced the expression of IL-A, TNF-a and MIF levels in the lung tissues. Histopathological study revealed the significant reduction of CLP-induced CLI in the curcumin-treated male albino rats. Taking all these data together, it is concluded that curcumin can act as a suitable therapeutic agent against CLP-induced CLI of male albino rats.

Is there a role of TNFR1 in acute lung injury cases associated with extracorporeal circulation?

The signaling pathway for tumor necrosis factor-α (TNF-α) and its receptors is up-regulated during extracorporeal circulation (ECC), and recruits blood neutrophil into the lung tissue, which results in acute lung injury (ALI). In this study, we evaluated the role of tumor necrosis factor receptor 1 (TNFR1) in ECC-induced ALI by blocking TNF-α binding to TNFR1 with CAY10500. Anesthetized Sprague-Dawley (SD) rats were pretreated intravenously with phosphate buffered saline (PBS) or vehicle (0.3 ml ethanol IV) or CAY10500, and then underwent ECC for 2 h. The oxygenation index (OI) and pulmonary inflammation were assessed after ECC. OI was significantly decreased, while TNF-α and neutrophil in bronchoalveolar lavage fluid (BALF) and plasma TNF-α increased after ECC. Pretreatment of CAY10500 decreased plasma TNF-α level, but did not decrease TNF-α levels and neutrophil counts in BALF or improve OI. Lung histopathology showed significant alveolar congestion, infiltration of the leukocytes in the airspace, and increased thickness of the alveolar wall in all ECC-treated groups. CAY10500 pretreatment slightly reduced leukocyte infiltration in lungs, but did not change the wet/dry ratio in the lung tissue. Blocking TNF-α binding to TNFR1 by CAY10500 intravenously slightly mitigates pulmonary inflammation, but cannot improve the pulmonary function, indicating the limited role of TNFR1 pathway in circulating inflammatory cell in ECC-induced ALI.

Curcumin protects against sepsis-induced acute lung injury in rats

The present study aimed to investigate the effect of curcumin on sepsis-induced acute lung injury (ALI) in rats, and explore its possible mechanisms. Male Sprague-Dawley rats were randomly divided into the following five experimental groups (n = 20 per group): animals undergoing a sham cecal ligature puncture (CLP) (sham group); animals undergoing CLP (control group); or animals undergoing CLP and treated with vehicle (vehicle group), curcumin at 50 mg/kg (low-dose curcumin [L-Cur] group), or curcumin at 200 mg/kg (high-dose curcumin [H-Cur] group).At 6, 12, 24 h after CLP, blood, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The lung wet/dry weight (W/D) ratio, protein level, and the number of inflammatory cells in the BALF were determined. Optical microscopy was performed to examine the pathologic changes in lungs. Myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, as well as superoxidase dismutase (SOD) activity were measured in lung tissues. The expression of inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interluekin-8 (IL-8), and macrophage migration inhibitory factor (MIF) were determined in the BALF. Survival rates were recorded at 72 h in the five groups in another experiment. Treatment with curcumin significantly attenuated the CLP-induced pulmonary edema and inflammation, as it significantly decreased lung W/D ratio, protein concentration, and the accumulation of the inflammatory cells in the BALF, as well as pulmonary MPO activity. This was supported by the histopathologic examination, which revealed marked attenuation of CLP-induced ALI in curcumin treated rats. In addition, curcumin significantly increased SOD activity with significant decrease in MDA content in the lung. Also, curcumin caused down-regulation of the inflammatory cytokines TNF-α, IL-8, and MIF levels in the lung. Importantly, curcumin improved the survival rate of rats by 40%-50% with CLP-induced ALI. Taken together, these results demonstrate the protective effects of curcumin against the CLP-induced ALI. This effect can be attributed to curcumin ability to counteract the inflammatory cells infiltration and, hence, ROS generation and regulate cytokine effects.

The preventative role of curcumin on the lung inflammatory response induced by cardiopulmonary bypass in rats

BACKGROUND

Acute lung injury is a frequent complication after cardiopulmonary bypass (CPB). Recent studies have reported that NF-κB plays an important role in the pathogenesis of post-CPB pulmonary dysfunction. Several signaling pathways, including the TLR4 pathway, induce NF-κB leading to an inflammatory response. We designed this study to determine whether or not curcumin inhibits TLR4 and MyD88 protein levels and ameliorates lung inflammatory injury in a rat CPB model.

MATERIALS AND METHODS

Sprague-Dawley rats were randomly divided into the following five groups (n = 12): sham; control (CPB); vehicle; low-dose curcumin (L-Cur); and high-dose curcumin (H-Cur). The percutaneous beating heart CPB model of rat was established. Animals were pretreated with a single intraperitoneal injection of vehicle, L-Cur (50 mg/kg), or H-Cur (200 mg/kg) 2 h prior to CPB. Blood were sampled at various time points, then lung tissues and bronchoalveolar lavage fluid were harvested 24 h after CPB.

RESULTS

CPB induced a marked increase in the concentrations of interleukin-8, tumor necrosis factor-α, and matrix metalloproteinase-9 in plasma, bronchoalveolar lavage fluid, and lung tissues (P < 0.05 versus sham group), whereas curcumin pretreatment reduced these inflammatory markers. Curcumin had effective inhibitory effects on the expression of TLR4, MyD88, and NF-κB in lung tissues 24 h post-CPB (P < 0.05 versus vehicle group). Administration of curcumin remarkably decreased the lung injury score (L-Cur versus vehicle group, P = 0.024; H-Cur versus vehicle group, P = 0.013).

CONCLUSIONS

Curcumin may be an alternative therapy for protecting CPB-induced lung injury by suppressing the expression of inflammatory cytokines. This anti-inflammatory effect of curcumin is partly related to the inhibition of TLR4, MyD88, and NF-κB.

Methylprednisolone Fails to Preserve Pulmonary Surfactant and Blood–Air Barrier Integrity in a Porcine Cardiopulmonary Bypass Model

BACKGROUND

Pulmonary inflammation after cardiac surgery with cardiopulmonary bypass (CPB) has been linked to respiratory dysfunction and ultrastructural injury. Whether pretreatment with methylprednisolone (MP) can preserve pulmonary surfactant and blood-air barrier, thereby improving pulmonary function, was tested in a porcine CPB-model.

MATERIALS AND METHODS

After randomizing pigs to placebo (PLA; n = 5) or MP (30 mg/kg, MP; n = 5), animals were subjected to 3 h of CPB with 1 h of cardioplegic cardiac arrest. Hemodynamic data, plasma tumor necrosis factor-alpha (TNF-alpha, ELISA), and pulmonary function parameters were assessed before, 15 min after CPB, and 8 h after CPB. Lung biopsies were analyzed for TNF-alpha (Western blot) or blood-air barrier and surfactant morphology (electron microscopy, stereology).

RESULTS

Systemic TNF-alpha increased and cardiac index decreased at 8 h after CPB in PLA (P < 0.05 versus pre-CPB), but not in MP (P < 0.05 versus PLA). In both groups, at 8 h after CPB, PaO2 and PaO2/FiO2 were decreased and arterio-alveolar oxygen difference and pulmonary vascular resistance were increased (P < 0.05 versus baseline). Postoperative pulmonary TNF-alpha remained unchanged in both groups, but tended to be higher in PLA (P = 0.06 versus MP). The volume fraction of inactivated intra-alveolar surfactant was increased in PLA (58 +/- 17% versus 83 +/- 6%) and MP (55 +/- 18% versus 80 +/- 17%) after CPB (P < 0.05 versus baseline for both groups). Profound blood-air barrier injury was present in both groups at 8 h as indicated by an increased blood-air barrier integrity score (PLA: 1.28 +/- 0.03 versus 1.70 +/- 0.1; MP: 1.27 +/- 0.08 versus 1.81 +/- 0.1; P < 0.05).

CONCLUSION

Despite reduction of the systemic inflammatory response and pulmonary TNF-alpha generation, methylprednisolone fails to decrease pulmonary TNF-alpha and to preserve pulmonary surfactant morphology, blood-air barrier integrity, and pulmonary function after CPB.

ALTERATIONS IN INFLAMMATORY CAPACITY AND TLR EXPRESSION ON MONOCYTES AND NEUTROPHILS AFTER CARDIOPULMONARY BYPASS

Cardiopulmonary bypass (CPB) is associated with immune paresis, which predisposes to the development of postoperative sepsis. The aims of this study were to characterize the ex vivo cytokine responses to bacterial cell wall components in whole blood from patients undergoing CPB and to determine whether altered leukocyte expression of Toll-like receptors (TLRs) is involved in immune paresis after CPB. We recruited 6 patients undergoing routine cardiac surgery with CPB. Preoperatively, at the end of CPB and 20 h later, blood was obtained, anticoagulated, and leukocyte surface expression of CD14, TLR2, and TLR4 was quantified by flow cytometry. In addition, blood was incubated at 37 degrees C in the presence of peptidoglycan (PepG) and/or lipopolysaccharide (LPS), and plasma cytokines were measured by enzyme immunoassay. At the end of CPB, ex vivo production of tumor necrosis factor alpha, interleukin (IL) 1beta, IL-8, and IL-10 in response to PepG or LPS was virtually abolished (P < 0.05). The following day, there was recovery of all cytokine responses to PepG. Tumor necrosis factor alpha and IL-1beta responses to LPS partially recovered, whereas IL-8 and IL-10 responses recovered. At the end of CPB, there was more than 50% reduction in neutrophil TLR2 and TLR4 expression (P < 0.05), with recovery to baseline the following day. There was a 29% reduction in monocyte TLR4 expression at the end of CPB (P < 0.05) and more than 120% increase in monocyte TLR2 and 4 expression the following day (P < 0.05). In conclusion, reduced ex vivo production of cytokines cannot be fully accounted for by downregulation of TLR expression, although receptor upregulation may contribute to the later recovery of responsiveness.

Protection against lung damage in reduced-size liver transplantation

OBJECTIVE

This study examined the effect of ischemic preconditioning on pulmonary damage associated with reduced-size orthotopic liver transplantation (ROLT) and attempted to identify the underlying protective mechanisms.

DESIGN

Randomized and controlled animals study.

SETTING

Experimental laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

Lung damage was evaluated in ROLT with or without preconditioning. Nitric oxide and interleukin (IL)-1 actions were altered pharmacologically.

MEASUREMENTS AND MAIN RESULTS

IL-1, tumor necrosis factor (TNF)-alpha, soluble TNF receptors (sTNFR), and inflammatory response in lung were measured after ROLT. Our results indicate the involvement of IL-1 in the lung damage following ROLT. Ischemic preconditioning, mediated by nitric oxide, reduced IL-1 release and protected against lung damage. Nitric oxide synthesis inhibition in the preconditioned group led to increased IL-1 levels and increased lung damage following ROLT, whereas the addition of IL-1 receptor antagonist protected against the injurious effects of nitric oxide inhibition. In addition, nitric oxide pretreatment gave similar results in terms of IL-1alpha and lung protection to those found in preconditioning. The benefits to the lung attributable to IL-1 inhibition might be linked to the effect of this cytokine on sTNFR, an endogenous mechanism that modulates systemic TNF actions. In fact, strategies aimed at inhibiting IL-1 action, including IL-1 receptor antagonist, ischemic preconditioning, and nitric oxide donor, increased systemic sTNFR2 and decreased free TNF, following ROLT. Similarly, nitric oxide synthesis inhibition in the preconditioned group, which increased IL-1alpha and lung damage, reduced systemic sTNFR2 and increased free TNF levels. These injurious effects were avoided when IL-1 action was inhibited.

CONCLUSIONS

Ischemic preconditioning and pharmacologic strategies that simulate its benefits protected against lung damage in an experimental model of ROLT. Our results also suggest a potential relationship between nitric oxide, IL-1, and TNF/sTNF in the benefits of preconditioning on the lung damage associated with ROLT.

Myocardial apoptosis after cardioplegic arrest in the neonatal lamb

OBJECTIVE

Myocardial apoptosis is observed after various cardiac injuries and is also a normal part of fetal cardiac development and early postnatal maturation. Cardioplegic arrest and reperfusion result in ischemic injury and oxidative stress, known triggers of apoptosis. Because the neonatal heart is in a proapoptotic state, we hypothesize that apoptosis is triggered after cardioplegic arrest in neonatal myocardium.

METHODS

We started neonatal lambs (6-8 days old, n = 5) on cardiopulmonary bypass and administered cold crystalloid cardioplegia at 20-minute intervals. Total crossclamp time was 70 minutes, and bypass time was 90 minutes. After a six-hour recovery period, the hearts were excised and examined by using TdT-mediated dUTP nick-end labeling; radiolabeled DNA electrophoresis; fluorimetric caspase 3, 8, and 9 activity assay; mRNA microarray; and Western immunoblotting. Control lambs were anesthetized but did not undergo operation (n = 5) or were started on cardiopulmonary bypass for 90 minutes but not arrested (n = 5).

RESULTS

Lambs subjected to cardioplegia had 5-fold more TdT-mediated dUTP nick-end labeling-positive nuclei compared with that seen in unoperated control animals (P =.007) and bypass-only control animals (P =.008). DNA laddering was present in all postcardioplegia hearts but absent among control hearts. Bad and Bcl-X mRNA transcription increased significantly. Caspase 3, 8, and 9 activities were slightly greater than those seen in control animals, but the differences were not significant. No change was detected in Bcl-2, Bax, or Bcl-xL proteins.

CONCLUSIONS

In a clinically relevant model of neonatal cardioplegic arrest, increased apoptotic cell death is present 6 hours after reperfusion, and both proapoptotic and antiapoptotic responses are triggered. The clinical implications of apoptosis after cardioplegic arrest remain undetermined.

Tumor necrosis factor and clinical and metabolic courses after cardiac surgery in children

OBJECTIVE

This study was undertaken to determine the relationship between plasma tumor necrosis factor concentrations and hemodynamic and metabolic parameters during the postoperative clinical course in children undergoing cardiac surgery.

METHODS

Tumor necrosis factor levels of 10 consecutive children undergoing surgery for repair of congenital heart defects were analyzed in blood samples drawn at predetermined time points during surgery and up to 24 hours thereafter. Clinical data were collected at these times for correlation to tumor necrosis factor levels.

RESULTS

All the patients survived. Tumor necrosis factor was detected in all 10 children. Tumor necrosis factor levels declined after induction of general anesthesia (201 +/- 65 pg/mL) steadily decreasing during surgery, reaching 80 +/- 50 pg/mL at 24 hours after the operation. Tumor necrosis factor levels were found to be inversely correlated with mean blood pressure values and indicators of acidosis (bicarbonate levels and base excess, P <.03). They were not correlated with the durations of cardiopulmonary bypass and aortic crossclamping.

CONCLUSIONS

Tumor necrosis factor released into the circulation during and after pediatric cardiac surgery under cardiopulmonary bypass may be related to the hemodynamic and acid-base changes observed after cardiac surgery. Elucidation of the relationship between tumor necrosis factor and patient outcome in high-risk patients awaits further studies.

Soluble cytokine receptors in biological therapy

Due to their fundamental involvement in the pathogenesis of many diseases, cytokines constitute key targets for biotherapeutic approaches. The discovery that soluble forms of cytokine receptors are involved in the endogenous regulation of cytokine activity has prompted substantial interest in their potential application as immunotherapeutic agents. As such, soluble cytokine receptors have many advantages, including specificity, low immunogenicity and high affinity. Potential disadvantages, such as low avidity and short in vivo half-lifes, have been addressed by the use of genetically-designed receptors, hybrid proteins or chemical modifications. The ability of many soluble cytokine receptors to inhibit the binding and biological activity of their ligands makes them very specific cytokine antagonists. Several pharmaceutical companies have generated a number of therapeutic agents based on soluble cytokine receptors and many of them are undergoing clinical trials. The most advanced in terms of clinical development is etanercept (Enbrel, Immunex), a fusion protein between soluble TNF receptor Type II and the Fc region of human IgG1. This TNF-alpha; antagonist was the first soluble cytokine receptor to receive approval for use in humans. In general, most agents based on soluble cytokine receptors have been safe, well-tolerated and have shown only minor side effects in the majority of patients. Soluble cytokine receptors constitute a new generation of therapeutic agents with tremendous potential for applications in a wide variety of human diseases. Two current areas of research are the identification of their most promising applications and characterisation of their long-term effects.

Pulmonary dysfunction after cardiac surgery

Postoperative lung injury is one of the most frequent complications of cardiac surgery that impacts significantly on health-care expenditures and largely has been believed to result from the use of cardiopulmonary bypass (CPB). However, recent comparative studies between conventional and off-pump coronary artery bypass grafting have indicated that CPB itself may not be the major contributor to the development of postoperative pulmonary dysfunction. In our study, we review the associated physiologic, biochemical, and histologic changes, with particular reference to the current understanding of underlying mechanisms. Intraoperative modifications aiming at limiting lung injury are discussed. The potential benefits of maintaining ventilation and pulmonary artery perfusion during CPB warrant further investigation.