Interleukin-6 delays neutrophil apoptosis

Why Is Iron Deficiency/Anemia Linked to Alzheimer's Disease and Its Comorbidities, and How Is It Prevented?

Impaired iron metabolism has been increasingly observed in many diseases, but a deeper, mechanistic understanding of the cellular impact of altered iron metabolism is still lacking. In addition, deficits in neuronal energy metabolism due to reduced glucose import were described for Alzheimer's disease (AD) and its comorbidities like obesity, depression, cardiovascular disease, and type 2 diabetes mellitus. The aim of this review is to present the molecular link between both observations. Insufficient cellular glucose uptake triggers increased ferritin expression, leading to depletion of the cellular free iron pool and stabilization of the hypoxia-induced factor (HIF) 1α. This transcription factor induces the expression of the glucose transporters (Glut) 1 and 3 and shifts the cellular metabolism towards glycolysis. If this first line of defense is not adequate for sufficient glucose supply, further reduction of the intracellular iron pool affects the enzymes of the mitochondrial electron transport chain and activates the AMP-activated kinase (AMPK). This enzyme triggers the translocation of Glut4 to the plasma membrane as well as the autophagic recycling of cell components in order to mobilize energy resources. Moreover, AMPK activates the autophagic process of ferritinophagy, which provides free iron urgently needed as a cofactor for the synthesis of heme- and iron-sulfur proteins. Excessive activation of this pathway ends in ferroptosis, a special iron-dependent form of cell death, while hampered AMPK activation steadily reduces the iron pools, leading to hypoferremia with iron sequestration in the spleen and liver. Long-lasting iron depletion affects erythropoiesis and results in anemia of chronic disease, a common condition in patients with AD and its comorbidities. Instead of iron supplementation, drugs, diet, or phytochemicals that improve energy supply and cellular glucose uptake should be administered to counteract hypoferremia and anemia of chronic disease.

Porphyromonas gingivalis Peptidyl Arginine Deiminase (PPAD) in the Context of the Feed-Forward Loop of Inflammation in Periodontitis

Periodontitis is a widespread chronic inflammatory disease caused by a changed dysbiotic oral microbiome. Although multiple species and risk factors are associated with periodontitis, Porphyromonas gingivalis has been identified as a keystone pathogen. The immune-modulatory function of P. gingivalis is well characterized, but the mechanism by which this bacterium secretes peptidyl arginine deiminase (PPAD), a protein/peptide citrullinating enzyme, thus contributing to the infinite feed-forward loop of inflammation, is not fully understood. To determine the functional role of citrullination in periodontitis, neutrophils were stimulated by P. gingivalis bearing wild-type PPAD and by a PPAD mutant strain lacking an active enzyme. Flow cytometry showed that PPAD contributed to prolonged neutrophil survival upon bacterial stimulation, accompanied by the secretion of aberrant IL-6 and TNF-α. To further assess the complex mechanism by which citrullination sustains a chronic inflammatory state, the ROS production and phagocytic activity of neutrophils were evaluated. Flow cytometry and colony formation assays showed that PPAD obstructs the resolution of inflammation by promoting neutrophil survival and the release of pro-inflammatory cytokines, while enhancing the resilience of the bacteria to phagocytosis.

Chitosan-Coated Solid Lipid Nano-Encapsulation Improves the Therapeutic Antiairway Inflammation Effect of Berberine against COPD in Cigarette Smoke-Exposed Rats

Berberine (Ber) is an isoquinoline alkaloid that has shown therapeutic potential in mice with chronic obstructive pulmonary disease (COPD). However, the therapeutic efficiency of Ber is restricted by its low aqueous solubility and bioavailability. Chitosan and solid lipid nanoparticles (SLNs) have demonstrated great abilities as delivery systems in enhancing the bioavailability of therapeutic compounds. The present study aimed to get together the biological features of SLNs with the advantages of chitosan to formulate an efficient nano-carrier platform for the oral delivery of Ber and evaluate the therapeutic effect of the prepared Ber-encapsulated nanoparticles on airway inflammation in cigarette smoke (CS)-induced COPD rats. The Ber-encapsulated SLE-chitosan formulation was manufactured using a modified solvent-injection method followed by a homogenization process. Physicochemical properties, encapsulation efficiency, in vitro stability and Ber release, and pharmacokinetics of the manufactured formulation were evaluated. The COPD rat model was developed by exposing animals to CS. To study the therapeutic efficiency of Ber-encapsulated SLE-chitosan nanoparticles and pure berberine, the histopathological changes of the lung tissues, levels of inflammatory cells and cytokines, and activities of myeloperoxidase (MPO) and superoxide dismutase (SOD) enzymes were evaluated in bronchoalveolar lavage fluid (BALF). Ber-encapsulated SLE-chitosan showed the particle size in nano-range with high stability and controlled slow-release profile in vitro in simulated gastric (pH 1.5) and intestinal (pH 6.8) fluids. Administration of Ber-loaded SLE-chitosan nanoparticles could significantly ameliorate inflammation scores in lung tissues and reduce levels of inflammatory cells (neutrophils and macrophages) and inflammatory cytokines (IL-1β, Il-6, Il-17, and TNFα) in BALF when compared with the pure Ber. SLE-chitosan-based nanoparticles can strongly improve the therapeutic anti-inflammatory impact of Ber against CS-induced airway inflammation in COPD rats, suggesting the promising application of Ber-encapsulated SLN-chitosan nanoparticles for treating COPD and other inflammation-mediated diseases.

Protocol for analysis of mouse neutrophil NETosis by flow cytometry

Studies involving neutrophils are steadily increasing, thus creating a need for more optimized and thorough protocols for studying neutrophil function. Here, we present our protocol for extracting mouse bone marrow neutrophils, estimating the purity of isolated neutrophils, and assessing their ability to induce NETosis upon an external cue. We test two isolation protocols that can be used to attain neutrophils to assess NETosis induction. This approach allows for the parallel assessment of NETosis induction in cohorts larger than 10 samples. For complete details on the use and execution of this protocol, please refer to Lu et al., 2021.

Macrophage Regulation of Granulopoiesis and Neutrophil Functions

Significance: Neutrophils are potent effector cells of innate immunity requiring precise regulation of their numbers and functions in blood and tissues. Recent Advances: Macrophages have emerged as modulators of neutrophil properties. In inflammatory conditions, tissue macrophages modulate neutrophil trafficking and activation. Further, macrophages govern granulopoiesis in the bone marrow hematopoietic niche. Interactions of macrophages and neutrophils can be induced by cytokines and damage-associated molecular patterns, and they are also regulated by oxidative signaling. Critical Issues: We review the impact of macrophages on neutrophil development and function, and its consequences in health and disease. Future Directions: Targeting the liaison between macrophages and neutrophils might provide an interesting therapeutic strategy to reduce tissue inflammation and promote immune tolerance. Antioxid. Redox Signal. 35, 182-191.

Identification of key signaling pathways induced by SARS-CoV2 that underlie thrombosis and vascular injury in COVID-19 patients

The SARS-CoV-2 pandemic has led to hundreds of thousands of deaths and billions of dollars in economic damage. The immune response elicited from this virus is poorly understood. An alarming number of cases have arisen where COVID-19 patients develop complications on top of the symptoms already associated with SARS, such as thrombosis, injuries of vascular system, kidney, and liver, as well as Kawasaki disease. In this review, a bioinformatics approach was used to elucidate the immune response triggered by SARS-CoV-2 infection in primary human lung epithelial and transformed human lung alveolar. Additionally, examined the potential mechanism behind several complications that have been associated with COVID-19 and determined that a specific cytokine storm is leading to excessive neutrophil recruitment. These neutrophils are directly leading to thrombosis, organ damage, and complement activation via neutrophil extracellular trap release.

Anti-apoptotic effects of human gingival mesenchymal stromal cells on polymorphonuclear leucocytes

OBJECTIVES

Polymorphonuclear leucocytes (PMNs) constitute the first line of host defence and are crucial in maintaining periodontal health. Their survival and function are modulated by mesenchymal stromal cells (MSCs) from different origin. Gingival MSCs (GMSCs) play an important role in maintaining oral health and in the initial inflammatory response. The present study aimed to investigate the effects of GMSCs on PMNs apoptosis and reactive oxygen species (ROS) production.

METHODS

PMNs were either directly incubated with untreated, interleukin (IL)-1β- or tumour necrosis factor (TNF)-α-treated GMSCs or stimulated with their conditioned media. Resulting ROS production was evaluated by dichlorofluorescin diacetate staining, whereas PMNs apoptosis was assessed by Annexin V staining, followed by flow cytometry analysis.

RESULTS

While conditioned media of untreated and TNF-α-treated GMSCs did not affect apoptosis of PMNs, it was significantly delayed by conditioned media of GMSCs treated with IL-1β. In direct co-culture, GMSCs exerted anti-apoptotic effects on PMNs independently of the previous stimulation. However, the strongest impact was observed by IL-1β-treated GMSCs. ROS production of PMNs was not influenced by GMSCs or their conditioned media.

CONCLUSION

This study demonstrates for the first time the immunomodulatory properties of GMSCs towards PMNs, revealing that IL-1β enhances anti-apoptotic effects of GMSCs.

Lack of Interleukin-6 Affects IFN-γ and TNF-α Production and Early In Vivo Control of Brucella abortus Infection

Interleukin-6 (IL-6) is a pleiotropic cytokine promptly produced in response to infections, which contributes to host defense through the stimulation of acute phase immune responses. Brucella abortus is an intracellular bacterium that causes chronic disease in humans and domestic animals and triggers a robust immune response, characterized by the production of inflammatory cytokines. However, the mechanisms of IL-6-related immune responses in the context of Brucella infections are not completely understood. In this report, we describe an increased susceptibility of IL-6 knockout (KO) mice in the early phase of Brucella infection. Furthermore, we demonstrate that IL-6 is required for interferon (IFN)-γ and tumor necrosis factor (TNF)-α induction by infected splenocytes, indicating a protective role for IL-6 against B. abortus that parallels with Th1 type of immune response. Additionally, IL-6 KO mice exhibited reduced splenomegaly during the early phase of the infection. Corroborating this result, IL-6 KO mice displayed reduced numbers of macrophages, dendritic cells, and neutrophils in the spleen and reduced myeloperoxidase activity in the liver compared to wild-type infected mice. However, we demonstrate that IL-6 is not involved in B. abortus intracellular restriction in mouse macrophages. Taken together, our findings demonstrate that IL-6 contributes to host resistance during the early phase of B. abortus infection in vivo, and suggest that its protective role maybe partially mediated by proinflammatory immune responses and immune cell recruitment.

Sputum and salivary protein biomarkers and point-of-care biosensors for the management of COPD

Chronic obstructive pulmonary disease (COPD) has become one of the most fatal diseases of the century considering mortality and morbidity levels worldwide. This disease is an inflammatory response to environmental stress and tobacco smoking. Although spirometry is the gold-standard diagnostic test administrated in primary and secondary care, it often exhibits low accuracy in cases of predicting disease worsening and possible bias due to the operator, patient, and conditions. Recent developments in proteomics research suggest that the presence of protein biomarkers can aid in the accurate diagnosis and prediction of disease outcomes. This review presents the cutting-edge research progress in the area of protein biomarkers towards the management of COPD. The literature review was confined to protein biomarkers in saliva and sputum because testing these bodily fluids shows great promise for point-of-care (POC) testing due to its practicality, non-invasiveness and inexpensive handling and sampling. Although it is conclusive that more studies on sputum and saliva are needed, this review studies the promising clinical value of interleukin (IL)-6 and IL-8, matrix metalloproteinase (MMP)-8 and MMP-9, C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and neutrophil elastase (NE). Following the critical analysis of salivary and sputum biomarkers, the recent development of POC biosensors for the multiplexed detection of biomarkers is also reported. Overall, the review aims to explore the possibility for the future development of POC sensors for chronic lung disease management utilizing clinically relevant biomarkers in saliva and sputum.

Stabilizing mast cells improves acute lung injury after orthotopic liver transplantation via promotion of apoptosis in polymorphonuclear neutrophils

Postoperative pulmonary complications including acute lung injury (ALI) and acute respiratory distress syndrome have contributed to mortality and morbidity of orthotopic liver transplantation (OLT) with unclear mechanisms. Mast cells (MCs) and polymorphonuclear neutrophils (PMNs) are the main inflammatory cells and participants in the process of ALI. The present study was designed to investigate the role of MCs and PMNs and their potential relation to ALI following OLT. Rat orthotopic autologous liver transplantation (OALT) model was designed to determine lung injury at different time points after liver reperfusion. We also evaluated the function of MCs and the effect of tumor necrosis factor-α (TNF-α) and tryptase on ALI and PMN apoptosis in rats subjected to OALT. Histological scores and inflammatory factor levels as well as PMN apoptosis were measured. Rats suffered from ALI after OALT, which was demonstrated by a collapse of the pulmonary architecture, pulmonary edema, and infiltration of inflammatory cells in alveolar and interstitial spaces, as well as increased levels of proinflammatory cytokines. ALI maximized at 8 h after OALT. However, PMN apoptosis lagged behind the pulmonary injury and maximized at 16 h after OALT, when the acute inflammation resolution initiated. MC stabilization, and tryptase and TNF-α inhibitors could significantly decrease the lung pathophysiologic scores accompanied by an increase in PMN apoptosis. ALI after OALT was associated with MC activation and PMN apoptosis. ALI progression might be affected by delayed PMN apoptosis, which was related to MC activation. Induction of PMN apoptosis might alleviate ALI after OALT.

Isolation and Characterization of a Human Fetal Mesenchymal Stem Cell Population: Exploring the Potential for Cell Banking in Wound Healing Therapies

Various cell-based therapies are in development to address chronic and acute skin wound healing, for example for burns and trauma patients. An off-the-shelf source of allogeneic dermal cells could be beneficial for innovative therapies accelerating the healing in extensive wounds where the availability of a patient’s own cells is limited. Human fetal-derived dermal fibroblasts (hFDFs) show high in vitro division rates, exhibit low immunological rejection properties, and present scarless wound healing in the fetus, and previous studies on human fetal tissue-derived cell therapies have shown promising results on tissue repair. However, little is known about cell lineage stability and cell differentiation during the cell expansion process, required for any potential therapeutic use. We describe an isolation method, characterize a population, and investigate its potential for cell banking and thus suitability as a potential product for cell grafting therapies. Our results show hFDFs and a bone marrow-derived mesenchymal stem cell (BM-MSC) line shared identification markers and in vitro multilineage differentiation potential into osteogenic, chondrogenic, and adipogenic lineages. The hFDF population exhibited similar cell characteristics as BM-MSCs while producing lower pro-inflammatory cytokine IL-6 levels and higher levels of the wound healing factor hepatocyte growth factor. We demonstrate in vitro differentiation of hFDFs, which may be a problem in maintaining long-term lineage stability, potentially limiting their use for cell banking and therapy development.

Immunological and Inflammatory Impact of Non-Intubated Lung Metastasectomy

Background: We hypothesized that video-assisted thoracic surgery (VATS) lung metastasectomy under non-intubated anesthesia may have a lesser immunological and inflammatory impact than the same procedure under general anesthesia. Methods: Between December 2005 and October 2015, 55 patients with pulmonary oligometastases (at the first episode) successfully underwent VATS metastasectomy under non-intubated anesthesia. Lymphocytes subpopulation and interleukins 6 and 10 were measured at different intervals and matched with a control group composed of 13 patients with similar clinical features who refused non-intubated surgery. Results: The non-intubated group demonstrated a lesser reduction of natural killer lymphocytes at 7 days from the procedure (p = 0.04) compared to control. Furthermore, the group revealed a lesser spillage of interleukin 6 after 1 (p = 0.03), 7 (p = 0.04), and 14 (p = 0.05) days. There was no mortality in any groups. Major morbidity rate was significantly higher in the general anesthesia group 3 (5%) vs. 3 (23%) (p = 0.04). The median hospital stay was 3.0 vs. 3.7 (p = 0.033) days, the estimated costs with the non-intubated procedure was significantly lower, even excluding the hospital stay. Conclusions: VATS lung metastasectomy in non-intubated anesthesia had significantly lesser impact on both immunological and inflammatory response compared to traditional procedure in intubated general anesthesia.

The role and regulation of apoptosis in sepsis

Today, sepsis continues to be a growing problem in the critically ill patient population. A number of laboratories have been interested in understanding how changes in immune cell apoptosis during sepsis appear to contribute to septic morbidity. Consistently, it has been found that immune cell apoptosis is altered in a variety of tissue sites and cell populations both in experimental animals and humans. While divergent mediators, such as steroids and TNF, contribute to some of these apoptotic changes, their effects are tissue and cell population selective. Inhibition of FasL—Fas signaling (by either FasL gene deficiency, in vivo gene silencing [siRNA] or with FasL binding protein) protects septic mice from the onset of marked apoptosis and the morbidity/mortality seen in sepsis. Further, this extrinsic apoptosis response appears to utilize aspects of the Bid-induced mitochondrial pathway. This is in keeping with the findings that pan-specific caspase inhibition or the overexpression of Bcl-2 also protect these animals from the sequellae of sepsis.

Neutrophil-Related Inflammatory Mediators in Septic Acute Respiratory Distress Syndrome

To disclose the participation of neutrophils in septic acute respiratory distress syndrome (ARDS), characteristics of various inflammatory mediators were examined in septic patients. Forty-seven gram-negative septic patients were divided into ARDS (n = 23) and non-ARDS (n = 24) groups at the transferred point to the intensive care unit. The mediators were measured simultaneously at the transferred point, and then subsequently on days 1, 3, and 5. At the transferred point, the ARDS group showed significantly higher levels of interleukin-8 (IL-8), macrophage inflammatory peptide-1-alpha (MIP-1-α), soluble intercellular adhesion molecule-1 (sICAM-1), and neutrophil elas-tase despite lower neutrophil counts compared to the non-ARDS group. The ARDS group sustained significantly higher levels of sICAM-1 until day 5 and neutrophil elas-tase until day 1 compare to the non-ARDS group. Furthermore, nonsurviving ARDS patients (n = 8) showed significantly higher levels of tumor necrosis factor-alpha, IL-6, IL-8, and IL-10 compared to surviving ARDS patients (n = 15) at the transferred point. In conclusion, neutrophil-related inflammatory mediators, IL-8, MIP-1-α, sICAM-1, and neutrophil elastase, appear to possibly participate in septic ARDS. Cytokines might also play an important role in the mortality of such cases.

Intestine immune homeostasis after alcohol and burn injury

Traumatic injury remains one of the most prevalent reasons for patients to be hospitalized. Burn injury accounts for 40,000 hospitalizations in the United States annually, resulting in a large burden on both the health and economic system and costing millions of dollars every year. The complications associated with postburn care can quickly cause life-threatening conditions including sepsis and multiple organ dysfunction and failure. In addition, alcohol intoxication at the time of burn injury has been shown to exacerbate these problems. One of the biggest reasons for the onset of these complications is the global suppression of the host immune system and increased susceptibility to infection. It has been hypothesized that infections after burn and other traumatic injury may stem from pathogenic bacteria from within the host's gastrointestinal tract. The intestine is the major reservoir of bacteria within the host, and many studies have demonstrated perturbations of the intestinal barrier after burn injury. This article reviews the findings of these studies as they pertain to changes in the intestinal immune system after alcohol and burn injury.

Environmental immune disruptors, inflammation and cancer risk

An emerging area in environmental toxicology is the role that chemicals and chemical mixtures have on the cells of the human immune system. This is an important area of research that has been most widely pursued in relation to autoimmune diseases and allergy/asthma as opposed to cancer causation. This is despite the well-recognized role that innate and adaptive immunity play as essential factors in tumorigenesis. Here, we review the role that the innate immune cells of inflammatory responses play in tumorigenesis. Focus is placed on the molecules and pathways that have been mechanistically linked with tumor-associated inflammation. Within the context of chemically induced disturbances in immune function as co-factors in carcinogenesis, the evidence linking environmental toxicant exposures with perturbation in the balance between pro- and anti-inflammatory responses is reviewed. Reported effects of bisphenol A, atrazine, phthalates and other common toxicants on molecular and cellular targets involved in tumor-associated inflammation (e.g. cyclooxygenase/prostaglandin E2, nuclear factor kappa B, nitric oxide synthesis, cytokines and chemokines) are presented as example chemically mediated target molecule perturbations relevant to cancer. Commentary on areas of additional research including the need for innovation and integration of systems biology approaches to the study of environmental exposures and cancer causation are presented.

Delayed neutrophil apoptosis mediates intermittent hypoxia-induced progressive heart failure in pressure-overloaded rats

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) and heart failure (HF) are common coexisting diseases. Intermittent hypoxia (IH), caused by repeated apnea/hypopnea events, accompanied by increased systemic inflammation, might contribute to the promotion of HF.

METHODS

To assess the hypothesis, rats were exposed to IH or normal air condition 4 weeks on the basis of normal heart function or pre-existing HF, which was induced by pressure overload caused by abdominal aortic constriction surgery performed 12 weeks earlier. Echocardiography was performed before and after IH exposure to evaluate left ventricular (LV) function. Serum concentrations of pro-inflammatory cytokines TNF-α and IL-6 were detected by enzyme-linked immunosorbent assay. Flow cytometric analysis was used to determine the apoptotic rate of polymorphonuclear neutrophils (PMNs).

RESULTS

The echocardiographic study showed a significant decrease in LV fractional shortening (FS) and ejection fraction (EF) as well as an increase in the LV relative wall thickness (RWT) index in HF rats, which was aggravated by further exposure to IH compared with single-handed HF-only and sham-IH and sham-control groups. A reduced PMN apoptotic rate was observed in HF-IH rats compared with HF-only, sham-IH, and sham-control rats. Serum concentrations of TNF-α and IL-6 were also increased in HF-IH rats, accompanied by delayed PMN apoptosis, indicating significant systemic inflammation induced by IH.

CONCLUSION

The results of this study demonstrated that IH aggravates LV remodeling and heart dysfunction in rats with pre-existing HF. Delayed neutrophil apoptosis, which was revealed in HF rats following exposure to IH, contributed to the exacerbation of myocardial damage and progression of heart dysfunction.

Biological responses of preosteoblasts to particulate and ion forms of Co-Cr alloy

This study compared the particulate and ion forms of a cobalt-chrome (Co-Cr) alloy on the differentiation/activation of preosteoblasts. Mouse preosteoblasts (MC3T3-E1) were cultured in an osteoblast-induction medium in the presence of particulate and ion forms of a Co-Cr alloy, followed by cell proliferation and cytotoxicity evaluations. The maturation and function of osteoblasts were assessed by alkaline phosphatase (ALP) assay and related gene expressions. Both particulate and ion forms of the metals significantly reduced the proliferation of MC3T3-E1 cells in a dose-dependent manner. Similarly, cells challenged with high concentrations of particles and ions exhibited a marked cytotoxic effect and diminished expression of ALP. Real-time (RT) polymerase chain reaction (PCR) data have suggested that cells with Co-Cr particles dramatically promoted over-expression of monocyte chemo-attractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), whereas Co(2+) ions treatment predominately up-regulated expressions of receptor activator of nuclear factor kappa-B ligand (RANKL), nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), and down-regulated expression of osteoprotegerin (OPG) and Osterix (Osx). Overall, this study provides evidence that both Co-Cr alloy particles and metal ions interfered with the MC3T3-E1 cells for their growth, maturation, and functions. Further, Co-Cr particles exhibited stronger effects on inflammatory mediators, while metal ions showed more influence on inhibition of osteoblast differentiation and promotion of osteoclastogenesis.

Epithelial adhesion molecules and the regulation of intestinal homeostasis during neutrophil transepithelial migration

Epithelial adhesion molecules play essential roles in regulating cellular function and maintaining mucosal tissue homeostasis. Some form epithelial junctional complexes to provide structural support for epithelial monolayers and act as a selectively permeable barrier separating luminal contents from the surrounding tissue. Others serve as docking structures for invading viruses and bacteria, while also regulating the immune response. They can either obstruct or serve as footholds for the immune cells recruited to mucosal surfaces. Currently, it is well appreciated that adhesion molecules collectively serve as environmental cue sensors and trigger signaling events to regulate epithelial function through their association with the cell cytoskeleton and various intracellular adapter proteins. Immune cells, particularly neutrophils (PMN) during transepithelial migration (TEM), can modulate adhesion molecule expression, conformation, and distribution, significantly impacting epithelial function and tissue homeostasis. This review discusses the roles of key intestinal epithelial adhesion molecules in regulating PMN trafficking and outlines the potential consequences on epithelial function.

Comparison between cigarette smoke-induced emphysema and cigarette smoke extract-induced emphysema

Background and objective

Emphysema is the main pathological feature of COPD and also is the focus of the related research. Although several emphysema animal models have been established, exact comparison of findings is seldom. The present study aimed to compare cigarette smoke (CS) exposure-induced emphysema model and intraperitoneal injection of cigarette smoke extract (CSE)-induced emphysema model to evaluate the effectiveness of the two different modeling methods.

Methods

Six-week-old male C57BL/6 J mice were used and randomly divided into two groups: CS exposure and intraperitoneal injection of CSE. Each group was subdivided into two subgroups: control and CS or CSE. Lung function, mean linear intercept (MLI), destructive index (DI), apoptotic index (AI), total and differential cells count in broncholavolar lavage fluid (BALF), SOD and IL-6 concentration in serum were measured.

Results

Compared with their respective controls, lung function was significantly decreased in CS and CSE groups (P < 0.01); MLI, DI, and AI of lung tissue were significantly higher in CS and CSE groups (P < 0.01); total number of leukocytes, the number and percentage of neutrophils (NEUs), and the number of macrophages (MAC) in BALF were significantly higher in CS and CSE groups (P < 0.01); SOD concentration in serum was significantly decreased in CS and CSE groups (P < 0.01); IL-6 concentration in serum was significantly increased in in CS and CSE groups (P < 0.01). There was no significant difference between CS group and CSE group in any of the parameters described above.

Conclusions

Both CS exposure and intraperitoneal injection of CSE could induce emphysema and the effectiveness of the two different modeling methods were equal.

Impaired cytokine expression, neutrophil infiltration and bacterial clearance in response to urinary tract infection in diabetic mice

Diabetic patients have increased susceptibility to infections, and urinary tract infections (UTI) are the most common type in women with diabetes mellitus. Knowledge of bacterial clearance effectiveness following UTI in diabetics is sparse. In this study, the effects of diabetes on bacterial clearance efficiency and components of the innate immune system in response to UTI in a murine model were investigated. Streptozotocin-induced diabetic and control female C57BL/6J mice were infected with uropathogenic Escherichia coli, and bacterial load, expression of chemokines, and neutrophil infiltration in the bladder over time were investigated. Expression levels of histone deacetylases were also measured to address a potential mechanism underlying the phenotype. Bacterial clearance during UTI was significantly prolonged in diabetic mice relative to controls. Neutrophil infiltration in bladder tissue and urine, and both mRNA and protein expression of chemokines MIP-2, KC, MCP-1 and IL-6 in bladder tissue were diminished at early time points after infection in diabetic mice relative to controls. In addition, mRNA levels of histone deacetylases 1-5 were increased in diabetic mice. This is the first study to show an association of impaired bacterial clearance in diabetic mice with suppression of UTI-induced chemokine expression and neutrophil infiltration in the bladder.

Expression of CD11b and CD18 on polymorphonuclear neutrophils stimulated with interleukin-2

Background

Interleukin-2 (IL-2) is a lymphocyte-activating and growth-promoting factor, and has been widely studied on T-cells and NK-cells. However, the interaction of polymorphonuclear neutrophils (PMNs) with IL-2 is poorly studied and thus, this study aimed at defining IL-2 participation in the expression of CD11b and CD18 on PMNs.

Material and methods

PMNs were isolated from heparinized whole blood of healthy donors. Purified cells were incubated with IL-2 (10 ng/ml) for 24 hours at 37°C in a humidified incubator with 5% CO₂. After 24 hours’ incubation, surface molecules (CD11b and CD18) were measured by flow cytometry.

Results

Interestingly, the antibodies of IL-2Rβ chain (CD122-FITC) were found in all observed cells. The induction of CD11b mean fluorescence intensity (MFI) in highly purified PMNs stimulated with IL-2 was clearly increased recording 43% in comparison to the freshly isolated PMNs and the un-stimulated PMNs which were found to be 23% and 28% of CD11b, respectively. Furthermore, flow cytometry analysis demonstrated that the highly purified PMNs exposed to IL-2 showed an increase in CD18 MFI, recording 47% with respect to that of the freshly isolated PMNs and PMNs cultured with the medium alone which showed a small amount of 38% and 27%, respectively.

Conclusions

Results demonstrated that CD11b and CD18 had been acquired on the surface of the IL-2-in vitro-activated PMNs. These findings indicated that IL-2 may play a crucial role in PMNs migration.

Use of pre-operative steroids in liver resection: a systematic review and meta-analysis

BACKGROUND

By attenuating the systemic inflammatory response to major surgery, the pre-operative administration of steroids may reduce the incidence of complications.

METHODS

A systematic review was conducted to identify randomized controlled trials (RCT) comparing pre-operative steroid administration with placebo during a liver resection. Meta-analyses were performed.

RESULTS

Five RCTs were identified including a total of 379 patients. Pre-operative steroids were associated with statistically significant reductions in the levels of serum bilirubin and interleukin 6 (IL-6) on post-operative day one. There was a trend towards a lower incidence of post-operative complications and prothrombin time (PT), but this did not reach statistical significance.

CONCLUSION

Pre-operative steroids may be associated with a clinically significant benefit in liver resection.

Serum proinflammatory cytokine levels and white blood cell differential count in patients with different degrees of severity of acute alcoholic pancreatitis

Several studies suggest that cytokines and neutrophils play an important role in the pathogenesis of acute pancreatitis (AP). The AIM OF THE STUDY was to assess the systemic release of proinflammatory cytokines and WBC (white blood cells) count with differential in patients with acute alcoholic pancreatitis (AAP) and to characterize the differences between patients with mild and severe forms of the disease.

MATERIAL AND METHODS

Thirty-five patients with the mild form of acute alcoholic pancreatitis (MAAP) were compared to 11 patients with severe acute alcoholic pancreatitis (SAAP). Serum levels of IL-6, IL-8, IL-12p40 and WBC differential count were measured every second day during the first week after admission.

RESULTS

During the course of the study, the average level of IL-6 was significantly (p<0.05) higher in patients with SAAP than in patients with the mild form of the disease (MAAP). Serum levels of IL-8 and IL-12p40 on admission were higher in patients with SAAP than in patients with MAAP but the difference was not statistically significant. Of all the types of WBCs, neutrophils were significantly (p<0.05) elevated the entire time in SAAP patients when compared to patients with MAAP on 5th and 7th day from admission to hospital.

CONCLUSIONS

Patients with SAAP had significantly higher proinflammatory cytokine IL-6 levels and neutrophil counts than patients with MAAP. The results suggest that proliferation and overstimulation of this subset of leukocytes might contribute to the development of the systemic inflammatory response in patients with SAAP.

Cytokine milieu in renal cavities of immunocompetent mice in response to intravenous challenge of Aspergillus flavus leading to aspergillosis

Investigations in mice have demonstrated that Aspergillus flavus is more virulent than all other Aspergillus species except A. tamari. However, there is a complete lack of information on the immune responses elicited by A. flavus in systemic model. This communication reports the progression of infection and cytokine profile in BALB/c mice in response to intravenous challenge of A. flavus. The pathogenesis of infection was evaluated morphologically and by the analysis of Colony Forming Units (CFUs) in kidney homogenates. The kinetics of regulated cytokines was determined in kidneys by cytokine-specific murine ELISA. During the initial phase of infection the rate of clearance of A. flavus was high, most likely through recruited neutrophils and the resident renal macrophages with concurrent significant release of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-12/IL-23p40, IL-6) indicating antifungal innate immune response to be active at the site. However, at 24h PI there was a significant rise of IL-17 and IL-23 suggesting the activation of IL-17/IL-23 axis of inflammation resulting in rise of CFU. The lack of significant induction in the anti-inflammatory cytokines like IL-4 and IL-10 confirmed the absence of Th2 type of response. In the late phase, after 3days post-infection, there was a rise in the number of pathogen in the kidneys as determined by histopathology and CFU counts. The A. flavus hyphae were evident in the renal pelvis and ureter and we propose the production of blastoconidia by metamorphosed hyphae.

T-cell proliferation by surface molecules expression on polymorphonuclear neutrophils stimulated with IL-4 in superantigen presence

BACKGROUND

Polymorphonuclear neutrophils (PMNs) were originally described as short lived and terminally differentiated phagocytes that contribute only to the innate immune response. Some studies of PMNs cytokine production and expression of numerous cell surface proteins has suggested that PMNs are likely to influence adaptive responses and may satisfy the criteria of antigen presenting cells.

AIM OF THE STUDY

This work aimed to study the effect of IL-4 in the function of PMNs as antigen presenting cells.

METHODS

Flow cytometry was used in the present study for the detection of cell surface human leukocyte antigen (HLA) class II, CD80 and CD86 required for antigen presentation and subsequent T-cell activation in the presence of Staphylococcus aureus enterotoxin (A). Human peripheral blood neutrophils were used for this purpose.

RESULTS

This study has shown that IL-4 stimulated PMNs for 24h expressed HLA class II, CD80 and CD86 that involved in antigen presentation. It also indicated that co-cultivation of IL-4 stimulated PMNs with autologous T-cells and in the presence of S. aureus enterotoxin (A) induced T-cell proliferation.

CONCLUSIONS

In vitro stimulation of PMNs with IL-4 showed expression of surface molecules involved in antigen presentation. In addition, the co-culture of T-Cells and stimulated PMNs showed high T-Cells proliferation in the presence of superantigens.

Hematopoietic stem-progenitor cells restore immunoreactivity and improve survival in late sepsis

Sepsis progresses from an early/acute hyperinflammatory to a late/chronic hypoinflammatory phase with immunosuppression. As a result of this phenotypic switch, mortality in late sepsis from persistent primary infection or opportunistic new infection often exceeds that in acute sepsis. Emerging data support that persistence of the hypoinflammatory (hyporesponsive) effector immune cells during late sepsis might involve alterations in myeloid differentiation/maturation that generate circulating repressor macrophages that do not readily clear active infection. Here, we used a cecal ligation and puncture (CLP) murine model of prolonged sepsis to show that adoptive transfer of CD34(+) hematopoietic stem-progenitor cells after CLP improves long-term survival by 65%. CD34(+) cell transfer corrected the immunosuppression of late sepsis by (i) producing significantly higher levels of proinflammatory mediators upon ex vivo stimulation with the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide, (ii) enhancing phagocytic activity of peritoneal macrophages, and (iii) clearing bacterial peritonitis. Improved immunity by CD34(+) cell transfer decreased inflammatory peritoneal exudate of surviving late-sepsis mice. Cell tracking experiments showed that the transferred CD34(+) cells first appeared in the bone marrow and then homed to the spleen and peritoneum. Because CD34(+) cells did not affect the early-phase hyperinflammatory response, it is likely that the newly incorporated pluripotent CD34(+) cells differentiated into competent immune cells in blood and tissue, thereby reversing or replacing the hyporesponsive endotoxin-tolerant cells that occur and persist after the initiation of early sepsis.

Lung function and inflammation during murine Pseudomonas aeruginosa airway infection

BACKGROUND

Following any acute irritation lung function declines rapidly. Reasons for pulmonary deterioration in humans had been attributed to the action of either interleukin-6 or interleukin-8 in the lungs.

OBJECTIVES

The present study investigates the association between immune response and decline in lung function in a murine bacterial lung infection model.

METHODS

Upon intratracheal inoculation of C57BL/6J mice with a sublethal dose of Pseudomonas aeruginosa lung function, cytokine, chemokine and cytometry in bronchoalveolar lavage fluid, bacterial counts and lung histology was assessed at 2, 4, 6, 8, 10, 12, 18, 24, 48, 72, 96 and 120 h post inoculation.

RESULTS

Lung function measured by non-invasive head-out spirometry decreased most strongly between 6 and 10 h post inoculation and required up to 72 h to recover for selected parameters. CFU counts in the lungs peaked at 4h post inoculation with subsequent decline until at 24-48 h post inoculation background levels were reached. Cytokine and chemokine responses could be separated into an early pro-inflammatory phase (2-8h post inoculation; mainly tumor-necrosis factor α (TNFα) and interleukin-1α driven) and a late anti-inflammatory resolution phase (starting at 24h post inoculation; mainly interleukin-10 and interleukin-4 driven). Interleukin-6 levels correlated with the deterioration of lung function. Lung histology showed maximal changes in terms of inflammation and edema between 24 and 48 h post inoculation.

CONCLUSIONS

In summary, elevated interleukin-6, high local neutrophil counts and lung edema were found to be the most characteristic signs of the transient period of deterioration of lung function.

The biology of aging and frailty

In developing and validating the concept of frailty as a geriatric syndrome, it has been necessary to distinguish the clinical expression of frailty from normal age-related changes and other age-related disease pathologies. A framework for excluding potentially confounding disease and a working clinical tool to diagnose frailty have been provided. The associations between frailty and other pathophysiologies has also been shown. However, investigating the underlying biologic basis for the geriatric syndrome of frailty by studying basic homeostatic pathways and mechanisms has not proceeded at the same rate. The following article provides an overview of the homeostatic pathways emphasized in research on aging and explains how this science may help to stimulate frailty research.

Local inflammation occurs before systemic inflammation in patients with COPD

BACKGROUND AND OBJECTIVE

COPD is associated not only with an abnormal inflammatory response in the lung but also with systemic inflammation, including systemic oxidative stress, activation of circulating inflammatory cells and increased circulating levels of inflammatory cytokines. Understanding the nature and course of systemic inflammation in COPD is important given the potential for anti-inflammatory therapy. This study explored whether local and systemic inflammation occur concurrently in patients with COPD.

METHODS

Forty-four patients with stable COPD, 10 smoking controls and 10 non-smoking controls were enrolled in this observational study. Induced sputum and peripheral blood samples were obtained simultaneously for measurement of inflammatory cell numbers and the concentrations of IL-6 and CRP.

RESULTS

The total number of cells in the sputum total cell number, percentage of neutrophils and the concentration of IL-6 were significantly higher in smoking controls and patients with COPD than in non-smoking controls (P < 0.05 and P < 0.01, respectively). As the disease stage progressed, airway inflammatory cells and IL-6 levels increased. CRP levels in sputum were significantly higher in stage II, III and IV COPD patients than in smoking and non-smoking controls (P < 0.01). However, the peripheral WCC and percentage of neutrophils were similar in patients with COPD, smoking and non-smoking controls. Circulatory concentrations of IL-6 and CRP in stages III and IV COPD patients were significantly higher than in smoking and non-smoking controls (P < 0.05 and P < 0.01, respectively). Additionally, there were positive correlations between sputum and blood IL-6 and CRP levels (r = 0.566, P < 0.01 and r = 0.443, P < 0.01, respectively).

CONCLUSIONS

The increase in the inflammatory cell population and IL-6 and CRP levels in the airway may occur earlier than in the peripheral blood, and reflect the degree of airflow limitation better than do peripheral blood measurements. Systemic inflammation may be present in patients with severe or very severe COPD.

Serum markers of apoptosis decrease with age and cancer stage

The physical manifestations of aging reflect a loss of homeostasis that effects molecular, cellular and organ system functional capacity. As a sentinel homeostatic pathway, changes in apoptosis can have pathophysiological consequences in both aging and disease. To assess baseline global apoptosis balance, sera from 204 clinically normal subjects had levels of sFas (inhibitor of apoptosis), sFasL (stimulator of apoptosis), and total cytochrome c (released from cells during apoptosis) measured. Serum levels of sFas were significantly higher while sFasL and cytochrome c levels were lower in men compared to women. With increasing age there was a decrease in apoptotic markers (cytochrome c) and pro-apoptotic factors (sFasL) and an increase in anti-apoptotic factors (sFas) in circulation. The observed gender differences are consistent with the known differences between genders in mortality and morbidity. In a separate cohort, subjects with either breast (n = 66) or prostate cancer (n = 38) exhibited significantly elevated sFas with reduced sFasL and total cytochrome c regardless of age. These markers correlated with disease severity consistent with tumor subversion of apoptosis. The shift toward less global apoptosis with increasing age in normal subjects is consistent with increased incidence of diseases whose pathophysiology involves apoptosis dysregulation.

Postoperative suppression of inflammatory cytokines after distal gastrectomy in elderly patients

PURPOSE

Surgical procedures are being performed on elderly people with increasing frequency, but accordingly, postoperative complications and mortality rates are higher than for younger patients. We conducted this study to establish if cytokine responses after distal gastrectomy in elderly patients differ from those in younger patients.

METHODS

Twenty-one patients undergoing distal gastrectomy were divided into two groups based on age: the elderly group consisted of 10 patients aged >/=75 years, and the younger group consisted of 11 patients aged <65 years. Blood samples were collected from the patients preoperatively, and then on postoperative days (PODs) 1, 3, and 7, for analysis of interleukin (IL)-6, IL-8, IL-10, soluble tumor necrosis factor receptors (sTNF-R), and IL-1 receptor antagonist (IL-1ra); and also to measure TNF-alpha and IL-1beta after incubation with Escherichia coli lipopolysaccharide.

RESULTS

The IL-6 concentration and TNF-alpha on POD 1 were both significantly lower in the elderly group than in the younger group (P = 0.0058 and P = 0.022, respectively).

CONCLUSION

Cytokine profiles after distal gastrectomy in elderly patients differ from those in younger patients, with lower pro-inflammatory and inflammatory cytokine responses evident in the elderly.

Attenuation of lipopolysaccharide-induced acute lung injury by treatment with IL-10

BACKGROUND AND OBJECTIVE

The aim of this study was to characterize the changes in neutrophils and cytokines in BAL fluid following acute lung injury (ALI), and to determine the protective effect of post-injury treatment with IL-10.

METHODS

A rat model of ALI was established by evenly spraying LPS (16 mg/kg) into the lungs followed by observation for 48 h. Histological changes and the kinetics of neutrophil infiltration were evaluated in the injured lungs. The cytokines (TNF-alpha, IL-6, IL-10 and interferon-gamma) and macrophage-inflammatory protein (MIP-2) were measured in BAL fluid by ELISA. The activation of BAL fluid neutrophils was investigated after treatment with IL-10 in vitro. The protective effect on histology and MIP-2 levels of intra-tracheal instillation of IL-10 12 and 16 h after LPS treatment was studied in vivo.

RESULTS

Intra-tracheal instillation of LPS caused significant lung injury and the activation of neutrophils. The levels of TNF-alpha and IL-6 in BAL fluid peaked at 8 and 16 h after LPS instillation respectively. IL-10 levels reached a maximum at 16-24 h, at the beginning of resolution of tissue injury. IL-10 inhibited the activation of neutrophils in vitro and MIP-2 induction in vivo. IL-10 had a protective effect if it was administered 12 but not 16 h after LPS.

CONCLUSIONS

Neutrophils appeared to play an important role in ALI. Time-dependent treatment with IL-10 after intra-tracheal instillation of LPS was effective in protecting rats from ALI, probably by suppressing pulmonary infiltration with activated neutrophils.

Dysregulated apoptosis and NFkappaB expression in COPD subjects

BACKGROUND

The abnormal regulation of neutrophil apoptosis may contribute to the ineffective resolution of inflammation in chronic lung diseases. Multiple signalling pathways are implicated in regulating granulocyte apoptosis, in particular, NFkappaB (nuclear factor-kappa B) signalling which delays constitutive neutrophil apoptosis. Although some studies have suggested a dysregulation in the apoptosis of airway cells in chronic obstructive pulmonary disease (COPD), no studies to date have directly investigated if NFkappaB is associated with apoptosis of airway neutrophils from COPD patients. The objectives of this study were to examine spontaneous neutrophil apoptosis in stable COPD subjects (n = 13), healthy smoking controls (n = 9) and non-smoking controls (n = 9) and to investigate whether the neutrophil apoptotic process in inflammatory conditions is associated with NFkappaB activation.

METHODS

Analysis of apoptosis in induced sputum was carried out by 3 methods; light microscopy, Annexin V/Propidium iodide and the terminal transferase-mediated dUTP nick end-labeling (TUNEL) method. Activation of NFkappaB was assessed using a flow cytometric method and the phosphorylation state of IkappaBalpha was carried out using the Bio-Rad Bio-Plex phosphoprotein IkappaBalpha assay.

RESULTS

Flow cytometric analysis showed a significant reduction in the percentage of sputum neutrophils undergoing spontaneous apoptosis in healthy smokers and subjects with COPD compared to non-smokers (p < 0.001). Similar findings were demonstrated using the Tunel assay and in the morphological identification of apoptotic neutrophils. A significant increase was observed in the expression of both the p50 (p = 0.006) and p65 (p = 0.006) subunits of NFkappaB in neutrophils from COPD subjects compared to non-smokers.

CONCLUSION

These results demonstrate that apoptosis is reduced in the sputum of COPD subjects and in healthy control smokers and may be regulated by an associated activation of NFkappaB.

Apoptosis induced by lipid-associated membrane proteins from Mycoplasma penetrans is mediated by nuclear factor kappaB activation in mouse macrophage

Mycoplasma penetrans was shown to be involved in alteration of several eukaryotical cells functions and a causative agent in urogenital infectious diseases. Lipid-associated membrane proteins (LAMPs) may be responsible for the pathogenicity of some mycoplamas. In this study, we investigated whether M. penetrans LAMPs have pathogenic potential by inducing apoptosis in mouse macrophages. As analyzed by annexin-V - fluorescein isothiocyanate staining, significant early- and late-stage apoptosis was induced in M. penetrans LAMPs-challenged mouse macrophages. And agarose gel electrophoresis of the DNA of M. penetrans LAMPs-challenged cells revealed a ladder-like pattern of migration of DNA indicative of apoptosis. The possible molecular mechanisms responsible for the induction of apoptosis were also investigated by characterizing the activation of nuclear transcription factor kappaB (NFkappaB). NFkappaB was activated and translocated into the nucleus in mouse macrophages stimulated by M. penetrans LAMPs. The activation of NFkappaB and M. penetrans LAMPs-induced apoptosis in mouse macrophages was partially inhibited by the NFkappaB-specific inhibitor pyrrolidine dithiocarbamate. Thus, this study demonstrates that M. penetrans LAMPs may be an important etiological factor owing to their ability to induce apoptosis in mouse macrophages, which is probably mediated through the activation of NFkappaB.

Mechanism of salutary effects of finasteride on post-traumatic immune/inflammatory response: upregulation of estradiol synthesis

OBJECTIVE

The aim of this study was to evaluate whether pretreatment with finasteride, a 5alpha-reductase inhibitor, improves immune functions after trauma-hemorrhage.

SUMMARY BACKGROUND DATA

A number of studies have provided evidence for a gender dimorphism in host defense after trauma. Under stress conditions, such as trauma-hemorrhage, androgenic hormones have immunosuppressive effects, leading to increased susceptibility to sepsis, morbidity, and mortality. Testosterone is converted by 5alpha-reductase to 5alpha-dihydrotestosterone (DHT), a more potent androgen.

METHODS

Male C3H/HeN mice (8-10 weeks) were randomly assigned to receive finasteride or vehicle for 2 days and were then subjected to trauma-hemorrhage or sham operation. Trauma-hemorrhage was induced by a midline laparotomy and approximately 90 minutes of hemorrhagic shock (blood pressure, 35 mm Hg), followed by fluid resuscitation. Animals were killed 2 hours after resuscitation or sham procedure. Plasma levels and Kupffer cell production of cytokines (TNF-alpha, IL-6, IL-10, MCP-1, KC, and MIP-1alpha), lung neutrophil infiltration, and edema were evaluated.

RESULTS

Finasteride administration prevented the increase in cytokine plasma levels, decreased DHT, and increased 17beta-estradiol plasma concentrations. In addition, neutrophil infiltration and edema formation in the lung were reduced by finasteride. The salutary effects of finasteride were abrogated after coadministration with an estrogen receptor inhibitor (ICI 182,780). Increased Kupffer cell cytokine production normally observed after trauma-hemorrhage was prevented by treatment with finasteride.

CONCLUSION

These results suggest that inhibition of 5alpha-reductase leads to the conversion of testosterone to 17beta-estradiol, which produces salutary effects on the post-traumatic immune response.

Bax gene G(-248)A promoter polymorphism is associated with increased lifespan of the neutrophils of patients with osteomyelitis

BACKGROUND

Patients with osteomyelitis have a decreased rate of spontaneous apoptosis of their peripheral blood neutrophils. The G(-248)A polymorphism in the promoter region of the bax gene is associated with prolonged peripheral blood neutrophil survival in leukemic patients and may play some role in osteomyelitis.

METHODS

Bax G(-248)A promoter polymorphism was detected by DNA amplification using polymerase chain reaction, followed by restriction fragment length polymorphism analysis. Spontaneous apoptosis of peripheral blood neutrophils was measured by propidium iodide, annexin V, and flow cytometry, and Bax was quantified by Western blotting.

RESULTS

The bax promoter polymorphism A allele was significantly more frequent in 80 patients with osteomyelitis than in 220 healthy donors (18.1% vs. 10.6%, chi=4.84, odds ratio=1.81, 95% confidence interval=1.06-3.07, P=.028). Carriers of the A allele had a lower apoptotic rate of their peripheral blood neutrophils compared with noncarriers (33.3+/-16.7 vs. 43.1+/-3.1, P=.036). Patients with the AA genotype showed a lower expression of the Bax protein compared with carriers of other genotypes (P=.038).

CONCLUSIONS

Substitution of a nucleotide G-->A at position -248 in the bax gene was more frequent in patients with osteomyelitis and was associated with a longer lifespan of their peripheral blood neutrophils and lower Bax protein expression. These findings may play a role in the pathogenesis of osteomyelitis.

Adverse effects attributed to long-term radon inhalation in rats

The aim of this study was to investigate the adverse effect of long-term radon exposure on lung and blood cells in rats exposed to different radiation doses. Sprague-Dawley rats were exposed to radon for cumulative doses up to 66, 111, and 174 WLM (work level month). Total number and differential cells counts were determined in the bronchoalveolar lavage fluid (BALF) and the peripheral blood, as well as the activity of lactate dehydrogenase (LDH) and levels of glutathione (GSH) and total protein. DNA damage and interleukin (IL)-6 mRNA expression in BALF cells and peripheral blood mononuclear cells (PBMC) were detected by single cell gel electrophoresis (SCGE) and reverse-transcription polymerase chain reaction (RT-PCR), respectively. The results showed that radon-exposed lymphocytes were significantly lower and granulocytes higher in BALF compared to blood in exposed groups. The distance of DNA migration in the BALF and PBMC increased in a dose-dependent manner. A positive correlation between the PBMC and BALF cells in terms of DNA damage was noted. These findings suggested that PBMC might be used as a surrogate for BALF cells and thus the easier non-invasive ability to obtain PBMC may be useful in detection of lung DNA damage induced by radon.

Apoptosis and necrosis: a review for surgeons

BACKGROUND

Orderly cell death, termed apoptosis, features a morphology that is distinct from necrotic, or accidental, cell death. As the body of literature on apoptotic cell death grows, it is difficult for practicing surgeons to stay current with the involved mechanisms and their biologic significance.

METHODS

A MEDLINE/PubMed literature search was conducted, followed by manual crossreferencing, to identify relevant articles published in the English language between 1972 and 2004.

RESULTS

Apoptosis is now known to be involved in numerous disease states. Ischemia-reperfusion injury and acute pancreatitis are but two surgical entities in which the balance of apoptotic and necrotic cell death has a profound effect on clinical outcome. Similarly, the timing and extent of apoptosis in immune cells are important factors that determine the outcome of septic patients.

CONCLUSIONS

As already demonstrated in animal models, further research in this field will target opportunities for therapeutic intervention, making it increasingly important for clinicians to be familiar with apoptosis and necrosis, and their roles in normal and pathologic states.

Endotoxin inhibits apoptosis but induces primary necrosis in neutrophils

Lipopolysaccharide (LPS) is known to prolong the functional lifespan of neutrophils at a site of infection by preventing apoptosis through inhibitor of apoptosis proteins (IAPs). We hypothesized that the increased neutrophil lifespan ultimately leads to a larger fraction of cells undergoing uncontrolled, primary necrosis. Diluted venous whole blood was incubated with increasing concentrations of LPS for up to 36 hr. The percentages of apoptotic, necrotic and viable neutrophils were assessed using the Annexin V/propidium iodide flow cytometric assay. LPS led to a reduction of neutrophil apoptosis and increased the number of viable cells at 12, 24, and 36 hr of incubation. At the same time intervals, there was a significant increase in the percentage of cells undergoing primary necrosis for all concentrations of LPS (e.g., 10 ng/ml LPS at 24 h produced a mean increase from 9.6% in controls to 30.6%, p < 0.001). This increase in direct neutrophil necrosis following LPS activation may amplify local proinflammatory effects through less well controlled release of neutrophil contents into surrounding tissue.

Immediate-early antigen expression and modulation of apoptosis after in vitro infection of polymorphonuclear leukocytes by human cytomegalovirus

Polymorphonuclear leukocytes (PMNL) are a major carrier of human cytomegalovirus (CMV) in viremic immunodepressed patients. We transmitted infectious virions and viral components to PMNL by coculturing these cells with infected human embryonic lung fibroblasts (HELF) or human umbilical vein endothelial cells (HUVEC). Quantitative time-course analysis of viral DNA and protein expression in PMNL, after functional separation from infected donor cells, indicated the initiation of viral cycling, with immediate-early protein expression. No viral replication or early or late gene expression was observed, but infected PMNL were able to infect naive fibroblasts more than 48 h after the end of co-culture. PMNL apoptosis was significantly delayed during co-culture with infected or uninfected HUVEC, and this phenomenon did not require contact between the two cell populations. The increased production of IL-8 in the same culture conditions that protect PMNL from apoptosis, associated with the reversion of this protection by inhibiting or depleting this factor in the culture media, targets this cytokine as a likely candidate for this protective effect. These data suggest that PMNL play a key role in virus dissemination in vivo, through their interactions with infected endothelial cells.

Pathophysiology of polytrauma

Immediate and early trauma deaths are determined by primary brain injuries, or significant blood loss (haemorrhagic shock), while late mortality is caused by secondary brain injuries and host defence failure. First hits (hypoxia, hypotension, organ and soft tissue injuries, fractures), as well as second hits (e.g. ischaemia/reperfusion injuries, compartment syndromes, operative interventions, infections), induce a host defence response. This is characterized by local and systemic release of pro-inflammatory cytokines, arachidonic acid metabolites, proteins of the contact phase and coagulation systems, complement factors and acute phase proteins, as well as hormonal mediators: it is defined as systemic inflammatory response syndrome (SIRS), according to clinical parameters. However, in parallel, anti-inflammatory mediators are produced (compensatory anti-inflammatory response syndrome (CARS). An imbalance of these dual immune responses seems to be responsible for organ dysfunction and increased susceptibility to infections. Endothelial cell damage, accumulation of leukocytes, disseminated intravascular coagulation (DIC) and microcirculatory disturbances lead finally to apoptosis and necrosis of parenchymal cells, with the development of multiple organ dysfunction syndrome (MODS), or multiple organ failure (MOF). Whereas most clinical trials with anti-inflammatory, anti-coagulant, or antioxidant strategies failed, the implementation of pre- and in-hospital trauma protocols and the principle of damage control procedures have reduced post-traumatic complications. However, the development of immunomonitoring will help in the selection of patients at risk of post-traumatic complications and, thereby, the choice of the most appropriate treatment protocols for severely injured patients.

Off-pump coronary artery bypass grafting attenuates proinflammatory markers

OBJECTIVE

Cardiac surgery with cardiopulmonary bypass (CPB) has been considered the main causative factors of postoperative inflammatory reactions. The aim of this study was to compare surrogate markers of the proinflammatory response in patients who underwent coronary artery bypass grafting (CABG) with or without CPB.

METHODS AND RESULTS

Twenty patients undergoing first-time CABG were enrolled in the study, 10 with and 10 without CPB. Blood samples were drawn at the following times: at the anesthetic induction, the end of surgery, and thereafter at 12 and 24 hours postoperatively. Neutrophil elastase, interleukin (IL)-6 , and serum soluble Fas were chosen to evaluate the extent of the systemic inflammatory response. The groups were similar in terms of age, gender ratio, number of grafts per patient. There were no operative mortality or serious postoperative complications. Two of each group received blood transfusion postoperatively. Neutrophil elastase showed a significantly higher value in the on-pump group compared with the off-pump group at the end of surgery. Soluble Fas level showed a higher value at the end of surgery compared with baseline, while it had no significant changes in the off-pump patients. IL-6 levels in the on-pump group were consistently higher compared to the off-pump group but showed no statistically significant differences between the groups.

CONCLUSION

Compared with off-pump CABG, on pump CABG induced higher serum levels of proinflammatory markers including neutrophil elastase and soluble Fas.