Expression of Toll-like receptors 2 and 4 on innate immunity cells modulated by cardiac surgical operation

Decreased toll-like receptor 4 and CD11b/CD18 expression on peripheral monocytes of hypertensive patients correlates with a lesser extent of endothelial damage: a preliminary study

BACKGROUND

Low-grade chronic inflammation is recognized to contribute to the physiopathology of arterial hypertension. Therefore, this study aimed to assess the pro-inflammatory phenotype of peripheral monocytes of hypertensive patients by analyzing Toll-like receptor 4 (TLR4) and CD11b/CD18 surface expression. In the second part, the influence of phenotypic alterations of monocytes on the endothelial status reflected by circulating endothelial cells (CECs) was evaluated.

PATIENTS

The study included 60 patients with arterial hypertension, who were divided into two subgroups based on the disease severity according to the applicable criteria. The mild hypertension and resistant hypertension groups included 30 patients each. The control group consisted of 33 normotensive volunteers matched for age and sex.

RESULTS

Both in the entire group of patients and individual subgroups, reduced surface expression of TLR4 and CD11b/CD18 was found compared to normotensive volunteers. A reduced percentage of monocytes with the CD14 + TLR4 + immunophenotype was correlated with a lower MFI level of CD18 and CD11b in the entire group of patients and after division only in the mild hypertension group. Reduced surface expression of TLR4 in hypertensive patients correlated with a lower number of CECs. This relationship was not observed in the resistant hypertension group; instead, an independent effect of reduced CD11b/CD18 expression on the reduction of CEC number was demonstrated.

CONCLUSION

Our preliminary study showed for the first time that hypertension of varying severity is accompanied by phenotypic changes in monocytes, manifested by reduced surface expression of both TLR4 and CD11b/CD18. These phenotypic changes were associated with a reduced degree of endothelial injury. Our study opens a new, unexplored area of research on the protective features of peripheral monocytes in hypertension.

Lung injury following cardiopulmonary bypass: a clinical update

INTRODUCTION

Cardiopulmonary bypass (CPB) is an integral component of cardiac surgery; however, one of its most critical complications is acute lung injury induced by multiple factors including systemic inflammatory response.

AREAS COVERED

The objective of this review is to investigate the multiple factors that can lead to CPB-induced lung injury. These include contact of blood components with the artificial surface of the CPB circuit, local and systemic inflammatory response syndrome (SIRS), lung ischemia/re-perfusion injury, arrest of ventilation, and circulating endotoxins. We also focus on possible interventions to curtail the negative impact of CPB, such as off-pump surgery, impregnation of the circuit with less biologically active substances, leukocyte depletion filters and ultrafiltration, and pharmacological agents such as steroids and aprotinin.

EXPERT OPINION

Although many aspects of CPB are proposed to contribute to lung injury, its overall role is still not clear. Multiple interventions have been introduced to reduce the risk of pulmonary dysfunction, with many of these interventions having shown promising results, significantly attenuating inflammatory mediators and improving post-operative outcome. However, since lung injury is multifactorial and affected by inextricably linked components, multiple interventions tackling each of them is required.

Expression of Toll-like receptors 2 and 4 on peripheral mononuclear cells (PBMCs) after laparoscopic cholecystectomy

Increasing evidence suggests that the course and intensity of inflammation, as well as repair processes, developed in response to stress, injury, and trauma, depend on the interaction between immediately released endogenous molecules, called alarmins or danger/damage-associated molecular patterns (DAMPs) and cellular pattern recognition receptors (PRR) including Toll-like receptors (TLRs) and activation of inflammatory/immune cells. Therefore, the aim of this study was to examine the expression of TLRs in peripheral blood mononuclear cells (PBMCs), CD3⁺, and CD14⁺ cells in control group and in patients before the laparoscopic cholecystectomy, and three and seven days after surgery. Flow cytometry was used to evaluate expression of TLR2 and TLR4. TLR2 and especially TLR4 expression levels on PBMCs were significantly lower in patients with asymptomatic cholelithiasis than in the control group. Laparoscopic surgery did not induce the significant changes in the expression of TLR2, both on PBMCs and CD3⁺ and CD14⁺ cell subpopulations. On the contrary, TLR4 expression level on PBMCs was significantly lower on the third and seventh postoperative day than before surgery. Collectively, the expression levels of cellular TLRs, and especially TLR2 and TLR4, might strongly influence the responsiveness of cells to DAMP activation, and in this way can regulate the intensity of inflammatory response to surgical injury.

RANK/RANKL Expression Is Induced by Cardiac Surgical Operation

Background: Cardiac surgery provokes a systemic inflammatory response in any patient. This complex body reaction involves also RANK/RANKL molecules which have been recently identified as principal regulators of bone metabolism. Aims: To follow the changes in the expression of RANK/RANKL molecules on innate immune cells of cardiac surgical patients. Patients and Methods: Twenty-six patients undergoing cardiac surgical were assigned to undergo coronary artery bypass grafting using either cardiopulmonary bypass (“on-pump”) or modified “miniinvasive on-pump”. The expression of RANK/RANKL was performed by flow cytometry. Results: Significantly increased expression of RANK on monocytes of “miniinvasive on-pump” patients was found at the 1st, the 3nd, and 7th postoperative days. The similar pattern was found also for monocyte RANKL expression. In addition, RANKL expression was significantly increased at the 3rd postoperative day in “on-pump” patient. No significant differences between “miniinvasive on-pump” and “on-pump” cardiac surgical patients were found. Conclusion: The expression of both RANK and RANKL molecules is significantly enhanced on monocytes of “miniinvasive on-pump” cardiac surgical patients.

TLR2 AND TLR4 EXPRESSION ON BLOOD MONOCYTES AND GRANULOCYTES OF CARDIAC SURGICAL PATIENTS IS NOT AFFECTED BY THE USE OF CARDIOPULMONARY BYPASS

Cardiac surgery is inseparably linked to the activation of innate immunity cells recognizing danger signals of both endogenous and exogenous origin via pattern recognition receptors such as TLR receptors. Therefore, we followed by flow cytometry TLR2 and TLR4 expression on blood monocytes and granulocytes of patients who underwent coronary artery bypass grafting using beating heart surgery (off-pump, n = 34), with use of standard cardiopulmonary bypass (CPB), (on-pump, n = 30), and miniinvasive CPB (mini on-pump, n = 25), respectively, before, during surgery, and up to 7th postoperative day. TLR2 and TLR4 expression both on monocytes and granulocytes was significantly diminished already at the end of CPB being highly significantly decreased at the end of surgery in all patients’ groups. TLR2 and TLR4 expression reached preoperative value at the 1st postoperative day being significantly higher at the 3rd postoperative day. Using intracellular staining we found the peak of TLR2 and TLR4 expression inside of monocytes and granulocytes at the first postoperative day in a subgroup of on-pump patients. In conclusion, TLR2 and TLR4 expression is significantly modulated in patients undergoing coronary artery bypass grafting as a part of adaptive homeostatic mechanisms induced by major surgery. The very surgical trauma is responsible for TLR2 and TLR4 modulation. Surprisingly, cardiopulmonary bypass itself was little contributing to the modulation of TLR2 and TLR4 expression.

Membrane and soluble Toll-like receptor 2 in patients with psoriasis treated by Goeckerman therapy

BACKGROUND

Toll-like receptor (TLR) 2 belongs to the large TLR receptor family comprised of at least 10 members with different roles in innate immunity. Psoriasis is recognized as a T-cell driven immune-mediated systemic inflammatory disease with a skin manifestation. An effective therapeutic approach to treat psoriasis is Goeckerman therapy (GT). The aim of this study was to assess both the kinetics of the expression of TLR2 on blood cells and the concentration of soluble (s)TLR2 in serum of patients with psoriasis and to examine the effect of GT on both TLR2 expression and sTLR2 level.

METHODS

Both membrane and sTLR2 were determined in 20 patients and 20 healthy controls. sTLR2 was evaluated by enzyme-linked immunosorbent assay. Flow cytometry method was used to determine the expression of membrane TLR2 of monocytes and granulocytes.

RESULTS

The serum level of sTLR2 was significantly lower (P < 0.0001) in patients both before and after GT compared to the control group. Compared to the membrane expression of TLR2 on monocytes of healthy blood donors, TLR2 expression was significantly higher in patients both before and after GT (P = 0.0001). Similarly, TLR2 expression on granulocytes was significantly higher in patients both before (P = 0.0061) and after (P < 0.0001) therapy than in control.

CONCLUSIONS

Membrane and soluble TLR2 may be involved in the pathogenesis of psoriasis. Both remained unchanged by GT.

TLR2 in pleural fluid is modulated by talc particles during pleurodesis

The aim of this study was to examine the role of TLR2 molecule in pleural space during thoracoscopic talc pleurodesis period in patients with malignant pleural effusion. We analyzed TLR2 molecule in soluble form as well as on membrane of granulocytes in pleural fluid. Pleural fluid examination was done at three intervals during pleurodesis procedure: 1st—before the thoracoscopic procedure, 2nd—2 hours after the terminating thoracoscopic procedure with talc insufflation, 3rd—24 hours after the thoracoscopic procedure. We reported significant increase of soluble TLR2 molecule in pleural fluid effusion during talc pleurodesis from preoperative value. This increase was approximately 8-fold in the interval of 24 hours. The changes on granulocyte population were quite different. The mean fluorescent intensity of membrane TLR2 molecule examined by flow cytometry on granulocyte population significantly decreased after talc exposure with comparison to prethoracoscopic density. To estimate the prognostic value of TLR2 expression in pleural fluid patients were retrospectively classified into either prognostically favourable or unfavourable groups. Our results proved that patients with favourable prognosis had more than 3-fold higher soluble TLR2 level in pleural fluid early, 2 hours after talc pleurodesis intervention.

The dynamics of selected local inflammatory markers to talc in the treatment of malignant pleural effusions

BACKGROUND

Malignant pleural effusions accumulate in the space between the visceral (inner) layer covering the lungs and the parietal (outer) layer covering the chest wall. Larger effusions compress the pulmonary parenchyma resulting in increasing dyspnoea. Treatment is always local and palliative. Among others, chemical pleurodesis using talc can be performed in selected patients. Talc is hydrated magnesium silicate (chemically H₂Mg₃(SiO₃)₄) and has been used for pleurodesis since 1935. Videothoracoscopic talc powder insufflation (talc poudrage) is the most effective.However, markers of inflammatory reactions to extraneous substances like talc are not fully understood. The aim of this study was to assess the course of local inflammatory changes in the pleural cavity after talc insufflation.

METHODS

The Department of Cardiac Surgery of the Faculty of Medicine and University Hospital in Hradec Kralove, treated 47 patients aged 65 on average; 29 males and 18 females with proven recurrent malignant pleural effusion of various aetiologies from January 2009 to December 2010. They were retrospectively divided into group A (40 patients) without recurring effusion, and group B (7 patients) with recurring effusion and the need for thoracentesis or chest drainage during the 9-month monitoring.

RESULTS

Major findings were made in soluble forms of cell receptors. Group B showed statistically higher levels of the anti-inflammatory form of sCD-163 receptor in pleural fluid before the talc poudrage. This showed limited ability to create an adequate inflammatory response to external stimuli. This group also showed lower levels of the inflammatory form of sTLR-2 receptor immediately after the talc insufflation. This revealed low local reactivity to external stimuli. The effect of the treatment was not influenced by morphologic tumour type. No statistically significant differences in postoperative complications were found. This confirmed the safety of both videothoracoscopy and treatment.

CONCLUSIONS

There was no correlation between the type of malignant affection and the outcome of the chemical pleurodesis. Patients with relapsing effusion have higher values of concentration of anti-inflammatory sCD-163 in pleural fluid even before the application of talc, and lower levels of concentration of inflammatory sTLR-2 immediately after application of talc.

Toll Like Receptors Signaling Pathways as a Target for Therapeutic Interventions

This review summarizes the key role of Toll-Like Receptor (TLRs) molecules for igniting the immune system. Activated by a broad spectrum of pathogens, cytokines or other specific molecules, TLRs trigger innate immune responses. Published data demonstrate that the targeting and suppression of TLRs and TLR-related proteins with particular inhibitors may provide pivotal treatments for patients with cancer, asthma, sepsis, Crohn's disease and thrombosis. Many drugs that target cytokines act in the late phases of the activated pathways, after the final peptides, proteins or glycoproteins are formed in the cell environment. TLR activity occurs in the early activation of cellular pathways; consequently inhibiting them might be most beneficial in the treatment of human diseases.