Mechanisms of lymphocyte accumulation in pulmonary disease

Idiopathic pulmonary fibrosis: Addressing the current and future therapeutic advances along with the role of Sotatercept in the management of pulmonary hypertension

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and debilitating lung disease characterized by irreversible scarring of the lungs. The cause of IPF is unknown, but it is thought to involve a combination of genetic and environmental factors. There is no cure for IPF, and treatment is focused on slowing disease progression and relieving symptoms.

AIMS

We aimed in this review to investigate and provide the latest insights into IPF management modalities, including the potential of Saracatinibas a substitute for current IPF drugs. We also investigated the therapeutic potential of Sotatercept in addressing pulmonary hypertension associated with IPF.

MATERIALS AND METHODS

We conducted a comprehensive literature review of relevant studies on IPF management. We searched electronic databases, including PubMed, Scopus, Embase, and Web of science.

RESULTS

The two Food and Drug Administration-approved drugs for IPF, Pirfenidone, and Nintedanib, have been pivotal in slowing disease progression, yet experimental evidence suggests that Saracatinib surpasses their efficacy. Preclinical trials investigating the potential of Saracatinib, a tyrosine kinase inhibitor, have shown to be more effective than current IPF drugs in slowing disease progression in preclinical studies. Also, Sotatercept,a fusion protein, has been shown to reduce pulmonary vascular resistance and improve exercise tolerance in patients with PH associated with IPF in clinical trials.

CONCLUSIONS

The advancements discussed in this review hold the promise of improving the quality of life for IPF patients and enhancing our understanding of this condition. There remains a need for further research to confirm the efficacy and safety of new IPF treatments and to develop more effective strategies for managing exacerbations.

Hypersensitivity Pneumonitis: Diagnostic and Therapeutic Challenges

Hypersensitivity pneumonitis (HP) is one of the most common interstitial lung diseases (ILD), that presents unique challenges for a confident diagnosis and limited therapeutic options. The disease is triggered by exposure to a wide variety of inciting antigens in susceptible individuals which results in T-cell hyperactivation and bronchioloalveolar inflammation. However, the genetic risk and the pathogenic mechanisms remain incompletely elucidated. Revised diagnostic criteria have recently been proposed, recommending to classify the disease in fibrotic and non-fibrotic HP which has strong therapeutic and outcome consequences. Confident diagnosis depends on the presence of clinical features of ILD, identification of the antigen(s), typical images on high-resolution computed tomography (HRCT), characteristic histopathological features, and lymphocytosis in the bronchoalveolar lavage. However, identifying the source of antigen is usually challenging, and HRCT and histopathology are often heterogeneous and not typical, supporting the notion that diagnosis should include a multidisciplinary assessment. Antigen removal and treating the inflammatory process is crucial in the progression of the disease since chronic persistent inflammation seems to be one of the mechanisms leading to lung fibrotic remodeling. Fibrotic HP has a few therapeutic options but evidence of efficacy is still scanty. Deciphering the molecular pathobiology of HP will contribute to open new therapeutic avenues and will provide vital insights in the search for novel diagnostic and prognostic biomarkers.

Influence of different volume therapies and pentoxifylline infusion on circulating soluble adhesion molecules in critically ill patients

OBJECTIVE

To study the influence of long-term volume therapy with different solutions and continuous administration of pentoxifylline on plasma concentrations of circulating adhesion molecules.

DESIGN

Prospective, randomized study.

SETTING

A surgical intensive care unit (ICU) of a university hospital.

PATIENTS

Forty-two patients with sepsis secondary to major surgery were included.

INTERVENTIONS

The patients were randomly separated into three groups. In group 1 (n=14), volume therapy was exclusively carried out with 10% low-molecular-weight hydroxyethyl starch solution. In group 2 (n=14), patients exclusively received 20% human albumin for volume therapy. In group 3 (n=14), volume therapy was not defined and pentoxifylline was continuously given (1.4 mg/kg/hr iv).

MEASUREMENTS AND MAIN RESULTS

From arterial blood samples, plasma concentrations of soluble adhesion molecules (endothelial leukocyte adhesion molecule-1 [soluble ELAM-1], intercellular adhesion molecule-1 [soluble ICAM-1], vascular cell adhesion molecule-1 [soluble VCAM-1], and soluble granule membrane protein-140) were serially measured on the day of admission to the ICU ("baseline" value) and during the next 5 days at noon. No significant differences between the three groups were found for macrohemodynamics. Soluble ELAM-1, soluble ICAM-1 and soluble VCAM-1 plasma concentrations were markedly higher than normal values at baseline in all groups. In the hydroxyethyl starch group, soluble ELAM-1 plasma concentration decreased to the normal range, whereas it further increased in the human albumin group and was almost unchanged in the pentoxifylline group. During the study period, soluble ICAM-1 and soluble VCAM-1 plasma concentrations remained unchanged in the hydroxyethyl starch group. However, these concentrations increased in the other groups. Soluble granule membrane protein-140 increased significantly only in the human albumin group (483 +/- 103 to 683 +/- 94 ng/mL). In the hydroxyethal starch-treated patients, Acute Physiology and Chronic Health Evaluation II score decreased significantly (from 24.3 +/- 3.4 at baseline to 17.0 +/- 3.3 at the end the study period). Only PaO2/FIO2 was correlated to plasma concentrations of adhesion molecules.

CONCLUSIONS

Sepsis is associated with markedly increased plasma concentrations of adhesion molecules, indicating endothelial activation or damage. By long-term volume therapy with hydroxyethal starch solution, these concentrations remained unchanged or even decreased, whereas in patients in whom human albumin was infused or pentoxifylline was given continuously, plasma concentration of soluble adhesion molecules further increased.

Circulating adhesion molecules in pediatric cardiac surgery

Cardiopulmonary bypass (CPB) may be associated with the risk of a "whole body inflammation." Adhesion molecules, such as endothelial leukocyte adhesion molecule (ELAM-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), seem to play a pivotal role in the inflammatory response. Soluble forms of these adhesion molecules may serve as markers of endothelial activation or damage. To elucidate whether plasma levels of soluble adhesion molecules differ between pediatric and adult cardiac surgery patients, 15 consecutive children younger than 5 yr undergoing CPB were prospectively studied and compared with adults scheduled for elective coronary artery bypass grafting and valve replacement. Plasma levels of circulating (soluble) adhesion molecules (sELAM-1, sICAM-1, sVCAM-1) were measured from arterial blood samples using enzyme-linked immunosorbent assays after induction of anesthesia (= "baseline"), during CPB, at the end of surgery, and on postoperative days 1 and 2. At baseline, plasma levels of all three soluble adhesion molecules were significantly higher in children than in adults. sELAM-1 and sICAM-1 plasma concentrations were even beyond normal in the children (sELAM-1: 88.8 +/- 13.8 ng/mL; sICAM-1: 349 +/- 27 ng/mL). During CPB and until the end of surgery, plasma levels of all adhesion molecules decreased in the children and remained almost unchanged in the adults. In the children, sELAM-1 remained lower than baseline values until the second postoperative day (45.2 +/- 12.2 ng/mL), whereas sICAM-1 increased in the postbypass period without, however, reaching baseline values (254 +/- 40 ng/mL).(ABSTRACT TRUNCATED AT 250 WORDS)

The CD4-associated tyrosine kinase p56lck is required for lymphocyte chemoattractant factor-induced T lymphocyte migration

Lymphocyte chemoattractant factor (LCF) is a polypeptide cytokine which induces both cell motility and activation of T lymphocytes. These LCF-induced events demonstrate an absolute requirement for the cell surface expression of CD4. Because many CD4-mediated T lymphocyte activation events have been demonstrated to require the association of the src-related tyrosine kinase p56lck with the cytoplasmic domain of CD4, we examined the role of p56lck in LCF-induced lymphocyte migration in a murine T cell hybridoma line expressing transfected human CD4. LCF induces the catalytic activity of CD4 associated p56lck at chemoattractant concentrations of cytokine. Hybridoma cells that express CD4 with cytoplasmic point mutations which uncouple the CD4-lck association lack both lck enzymatic activity and chemotactic responses to LCF. The enzymatic activity of lck however does not appear to be required for CD4-mediated migratory signal. First, the protein tyrosine kinase inhibitor herbimycin A blocked LCF-induced p56lck activation but had no effect on the LCF-induced motile response. Second, T cell hybridomas expressing a chimeric receptor combining the extracellular domain of human CD4 and murine p56lck which lacked the kinase domain had a normal LCF-induced motile response. We conclude from these observations that CD4-lck coupling is essential for LCF-induced T lymphocyte migration but the motile response is independent of the enzymatic activity of CD4-associated p56lck.

RETRACTED: Do plasma levels of circulating soluble adhesion molecules differ between surviving and nonsurviving critically ill patients?

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the editor In 2018, CHEST published a notice1 that all articles authored by Joachim Boldt be read with caution due to expressions of concern about falsified data. In 2020, CHEST received additional evidence of research misconduct and breaches of scientific integrity that were discovered following an investigation by the author's former institution, the University of Giessen2. In light of this new evidence, this article has been retracted by CHEST. 1. Irwin, R.S., MD, Master FCCP. Notice From the Editor in Chief. CHEST 153(3), p. 767. 2. Mukherjee, J. Statement on the scientific credibility of articles published by Joachim Boldt, formerly professor at Justus Liebig University (JLU), Giessen, Germany. https://ars.els-cdn.com/content/image/1-s2.0-S000709122030163X-mmc3.pdf.

Cytokine binding to CD4+ inflammatory cells: implications for asthma

While LCF is present in BAL early after antigen challenge, we know little about its other potential effects beyond CD4+ T cell, monocyte, and eosinophil chemotaxis and monocyte and CD4+ T cell activation. The work described here focuses on the hypothesis that the secreted protein products of T cells participate in the airway inflammatory process that underlies human asthma, and in particular that LCF could play an early role because of the unusual responsiveness of LCF-producing T to histamine. To date, most studies have addressed the measurement of cytokines derived from CD4+ T cells (e.g., IL-2, IL-3, IL-4, IL-5, and GM-CSF) in the airways of asthmatics, and attempted to correlate the presence of protein or mRNA with the complexion of the inflammatory infiltrate. These studies have been based upon the reports that there are increased numbers of CD4+ T cells in the airways of asthmatics, and that the presence of eosinophils might correlate with the secretion of TH2-type cytokines like IL-3, -4, and -5. Using this information as a background, our work has approached the problem in an entirely different way. We have focused our attention on the early events in antigen-induced asthma that are responsible for CD4+ cell accumulation in the lung, including CD4+ T cells, eosinophils, and monocytes. We have attempted to identify mechanisms by which mast cell mediators, in particular histamine, might play a role in the secretion of chemotactic lymphokines that are selective for CD4+ cells by using CD4 itself as a chemotactic factor receptor.(ABSTRACT TRUNCATED AT 250 WORDS)