The effect of LPS on neutrophils from patients with high risk of type 1 diabetes mellitus in relation to IL-8, IL-10 and IL-12 production and apoptosis in vitro

Histone H3 posttranslational modified enzymes defined neutrophil plasticity and their vulnerability to IL-10 in the course of the inflammation

BACKGROUND

Neutrophils are a heterogeneous population capable of antimicrobial functions associated with pre-activation/activation and tissue regeneration. The specific polarisation of immune cells is mediated by the modification of 'chromatin landscapes', which enables differentiated access and activity of regulatory elements that guarantee their plasticity during inflammation No specific pattern within histone posttranslational modifications (PTMs) controlling this plasticity has been identified.

METHODS

Using the in vitro model of inflammation, reflecting different states of neutrophils from resting, pre-activated cells to activated and reducing tissue regeneration, we have analysed 11 different histone posttranslational modifications (PTMs), PTM enzymes associated with remodelling neutrophil chromatin, and H3K4me3 ChIP-Seq Gene Ontology analysis focusing on the processes related to histone PTMs. These findings were verified by extrapolation to adequate clinical status, using neutrophils derived from the patients with sepsis (systemic septic inflammation with LPS-stimulated neutrophils), neuromyelitis optical spectrum disorders (aseptic inflammation with pre-activated neutrophils) and periodontitis (local self-limiting septic inflammation with IL-10-positive neutrophils).

RESULTS

Physiological activation of neutrophils comprises a pre-activation characterised by histone H3K27ac and H3K4me1, which position enhancers; direct LPS exposure is induced explicitly by H3K4me3 which marked Transcription Start Site (TSS) regions and low-level of H3K9me3, H3K79me2 and H3K27me3 which, in turn, marked repressed genes. Contrary to antimicrobial action, IL-10 positively induced levels of H3S10p and negatively H3K9me3, which characterised processes related to the activation of genes within heterochromatin mediated by CHD1 and H3K9me3 specific demethylase JMJD2A. IL-10 protects changes within histone PTMs induced by TNF or LPS that affected H3K4me3-specific methyltransferase SETD1A and MLL1. Neutrophils previously exposed to inflammatory factors become unvulnerable to IL-10 because previous LPS stimulation interrupts TSS regions marked by H3K4me3 of CHD1 and JMJD2A genes. Therefore, LPS-activated neutrophils are disabled to induce CHD1/JMJD2A enzymes by IL-10, making this process irreversible. Because transcription of JMJD2A and CHD1 also depends on TSS positioning by H3K4me3, neutrophils before LPS stimulation become insensitive to IL-10.

CONCLUSION

Neutrophils, once pre-activated by TNF or directly stimulated by LPS, become insensitive to the anti-inflammatory effects of IL-10, and vice versa; IL-10 protects neutrophils against these proinflammatory stimuli. This phenomenon is responsible for disturbing the natural process of resolving inflammation and tissue regeneration.

Oxidative Stress and Lipid Peroxidation: Prospective Associations Between Ferroptosis and Delayed Wound Healing in Diabetic Ulcers

Diabetic ulcers are one of the major complications of diabetes, and patients usually suffer from amputation and death due to delayed ulcer wound healing. Persistent inflammation and oxidative stress at the wound site are the main manifestations of delayed wound healing in diabetic ulcers. In addition, chronic hyperglycemia in patients can lead to circulatory accumulation of lipid peroxidation products and impaired iron metabolism pathways leading to the presence of multiple free irons in plasma. Ferroptosis, a newly discovered form of cell death, is characterized by intracellular iron overload and accumulation of iron-dependent lipid peroxides. These indicate that ferroptosis is one of the potential mechanisms of delayed wound healing in diabetic ulcers and will hopefully be a novel therapeutic target for delayed wound healing in diabetic patients. This review explored the pathogenesis of diabetic ulcer wound healing, reveals that oxidative stress and lipid peroxidation are common pathological mechanisms of ferroptosis and delayed wound healing in diabetic ulcers. Based on strong evidence, it is speculated that ferroptosis and diabetic ulcers are closely related, and have value of in-depth research. We attempted to clarify prospective associations between ferroptosis and diabetic ulcers in terms of GPX4, iron overload, ferroptosis inhibitors, AGEs, and HO-1, to provide new ideas for exploring the clinical treatment of diabetic ulcers.

A Bittersweet Response to Infection in Diabetes; Targeting Neutrophils to Modify Inflammation and Improve Host Immunity

Chronic and recurrent infections occur commonly in both type 1 and type 2 diabetes (T1D, T2D) and increase patient morbidity and mortality. Neutrophils are professional phagocytes of the innate immune system that are critical in pathogen handling. Neutrophil responses to infection are dysregulated in diabetes, predominantly mediated by persistent hyperglycaemia; the chief biochemical abnormality in T1D and T2D. Therapeutically enhancing host immunity in diabetes to improve infection resolution is an expanding area of research. Individuals with diabetes are also at an increased risk of severe coronavirus disease 2019 (COVID-19), highlighting the need for re-invigorated and urgent focus on this field. The aim of this review is to explore the breadth of previous literature investigating neutrophil function in both T1D and T2D, in order to understand the complex neutrophil phenotype present in this disease and also to focus on the development of new therapies to improve aberrant neutrophil function in diabetes. Existing literature illustrates a dual neutrophil dysfunction in diabetes. Key pathogen handling mechanisms of neutrophil recruitment, chemotaxis, phagocytosis and intracellular reactive oxygen species (ROS) production are decreased in diabetes, weakening the immune response to infection. However, pro-inflammatory neutrophil pathways, mainly neutrophil extracellular trap (NET) formation, extracellular ROS generation and pro-inflammatory cytokine generation, are significantly upregulated, causing damage to the host and perpetuating inflammation. Reducing these proinflammatory outputs therapeutically is emerging as a credible strategy to improve infection resolution in diabetes, and also more recently COVID-19. Future research needs to drive forward the exploration of novel treatments to improve infection resolution in T1D and T2D to improve patient morbidity and mortality.

Dance Training Improves Cytokine Secretion and Viability of Neutrophils in Diabetic Patients

Background

Evidence suggests that exercise improves neutrophil function. The decreased functional longevity of neutrophils and their increased clearance from infectious sites contribute to the increased susceptibility to infection and severity of infection observed in patients with diabetes.

Objective

Herein, we investigated the effects of a dance program on neutrophil number, function, and death in type 2 diabetes mellitus (T2DM) patients and healthy volunteers.

Methods

Ten patients with T2DM and twelve healthy individuals participated in a moderate-intensity dance training program for 4 months. The plasma levels of leptin, free fatty acids (FFAs), tumour necrosis factor-α (TNF-α), C-reactive protein (CRP), interleukin-1β (IL-1β), and interleukin-1 receptor antagonist (IL-1ra); neutrophil counts; extent of DNA fragmentation; cell membrane integrity; and production of TNF-α, interleukin-8 (IL-8), interleukin-6 (IL-6), and IL-1β in neutrophils were measured before and after training.

Results

Training reduced plasma levels of TNF-α (1.9-fold in controls and 2.2-fold in patients with T2DM) and CRP (1.4-fold in controls and 3.4-fold in patients with T2DM). IL-1ra levels were higher in the control group (2.2-fold) after training. After training, neutrophil DNA fragmentation was decreased in patients with T2DM (90%), while the number of neutrophils increased (70% in controls and 1.1-fold in patients with T2DM).

Conclusion

Dance training is a nonpharmacological strategy to reduce inflammation and improve neutrophil clearance in patients with T2DM.

The molecular biology in wound healing & non-healing wound

The development of molecular biology and other new biotechnologies helps us to recognize the wound healing and non-healing wound of skin in the past 30 years. This review mainly focuses on the molecular biology of many cytokines (including growth factors) and other molecular factors such as extracellular matrix (ECM) on wound healing. The molecular biology in cell movement such as epidermal cells in wound healing was also discussed. Moreover many common chronic wounds such as pressure ulcers, leg ulcers, diabetic foot wounds, venous stasis ulcers, etc. usually deteriorate into non-healing wounds. Therefore the molecular biology such as advanced glycation end products (AGEs) and other molecular factors in diabetes non-healing wounds were also reviewed.

Re-Examining Neutrophil Participation in GN

Significant advances in understanding the pathogenesis of GN have occurred in recent decades. Among those advances is the finding that both innate and adaptive immune cells contribute to the development of GN. Neutrophils were recognized as key contributors in early animal models of GN, at a time when the prevailing view considered neutrophils to function as nonspecific effector cells that die quickly after performing antimicrobial functions. However, advances over the past two decades have shown that neutrophil functions are more complex and sophisticated. Specifically, research has revealed that neutrophil survival is regulated by the inflammatory milieu and that neutrophils demonstrate plasticity, mediate microbial killing through previously unrecognized mechanisms, demonstrate transcriptional activity leading to the release of cytokines and chemokines, interact with and regulate cells of the innate and adaptive immune systems, and contribute to the resolution of inflammation. Therefore, neutrophil participation in glomerular diseases deserves re-evaluation. In this review, we describe advances in understanding classic neutrophil functions, review the expanded roles of neutrophils in innate and adaptive immune responses, and summarize current knowledge of neutrophil contributions to GN.

Periodontitis and type II diabetes: a two-way relationship

For many years an association between diabetes and periodontitis has been suspected. In more recent times this relationship has been suggested to be bidirectional with each condition being able to influence the other. In this review the two-way relationship between diabetes and periodontitis is considered. For this narrative review a very broad search strategy of the literature was developed using both EMBASE and MEDLINE (via PubMed) databases. The reference lists from the selected papers were also scanned, and this provided an additional source of papers for inclusion and further assessment. The data available suggest that diabetes is a risk as well as a modifying factor for periodontitis. Individuals with diabetes are more likely to have periodontitis and with increased severity when diabetes is uncontrolled/poorly controlled. Possible mechanisms of how diabetes affects periodontitis include adipokine-mediated inflammation, neutrophil dysfunction, uncoupling of bone and advanced glycation end-products-receptor for advanced glycation end-products interaction. Evidence is accruing to support how periodontitis can affect diabetes and complications associated with diabetes. There is some evidence demonstrating that periodontal therapy can result in a moderate improvement in glycaemic control. Available evidence indicates that diabetes and peridontitis are intricately interrelated and that each condition has the capacity to influence clinical features of each other.

Reduced neutrophil apoptosis in diabetic mice during staphylococcal infection leads to prolonged Tnfα production and reduced neutrophil clearance

Diabetes is a frequent underlying medical condition among individuals with Staphylococcus aureus infections, and diabetic patients often suffer from chronic inflammation and prolonged infections. Neutrophils are the most abundant inflammatory cells during the early stages of bacterial diseases, and previous studies have reported deficiencies in neutrophil function in diabetic hosts. We challenged age-matched hyperglycemic and normoglycemic NOD mice intraperitoneally with S. aureus and evaluated the fate of neutrophils recruited to the peritoneal cavity. Neutrophils were more abundant in the peritoneal fluids of infected diabetic mice by 48 h after bacterial inoculation, and they showed prolonged viability ex vivo compared to neutrophils from infected nondiabetic mice. These differences correlated with reduced apoptosis of neutrophils from diabetic mice and were dependent upon the presence of S. aureus and a functional neutrophil respiratory burst. Decreased apoptosis correlated with impaired clearance of neutrophils by macrophages both in vitro and in vivo and prolonged production of proinflammatory tumor necrosis factor alpha by neutrophils from diabetic mice. Our results suggest that defects in neutrophil apoptosis may contribute to the chronic inflammation and the inability to clear staphylococcal infections observed in diabetic patients.

Diabetes mellitus and apoptosis: inflammatory cells

Since the early observation that similarities between thyroiditis and insulitis existed, the important role played by inflammation in the development of diabetes has been appreciated. More recently, experiments have shown that inflammation also plays a prominent role in the development of target organ damage arising as complications, with both elements of the innate and the adaptive immune system being involved, and that cytokines contributing to local tissue damage may arise from both infiltrating and resident cells. This review will discuss the experimental evidence that shows that inflammatory cell-mediated apoptosis contributes to target organ damage, from beta cell destruction to both micro- and macro-vascular disease complications, and also how alterations in leukocyte turnover affects immune function.

Reduced cytokine production by glycogen-elicited peritoneal cells from diabetic rats

IL-1beta, TNF-alpha, cytokine-induced neutrophil chemoattractant-2alpha/beta, and IL-10 measurements were performed in elicited peritoneal cells from control, diabetic, and insulin-treated diabetic rats. Production/liberation of these cytokines was decreased in elicited peritoneal cells from diabetic rats. These changes were abolished by insulin treatment of diabetic rats. The alterations observed might be involved in the impaired inflammatory response and high occurrence of apoptosis observed in neutrophils under diabetic states.

Serum TNF-alpha level predicts nonproliferative diabetic retinopathy in children

The aim of this study was identification of the immunologic markers of the damage to the eye apparatus at early stages of diabetes mellitus (DM) type 1 children. One hundred and eleven children with DM type 1 were divided into two groups: those with nonproliferative diabetic retinopathy (NPDR) and without retinopathy. All the children had their daily urine albumin excretion, HbA1c, C-peptide measured, 24-hour blood pressure monitoring, and ophthalmologic examination. Levels of TNF-alpha, IL-6, and IL-12 in serum were measured by ELISA tests (Quantikine High Sensitivity Human by R&D Systems, Minneapolis, Minn, USA). The NPDR children demonstrated a significantly longer duration of the disease in addition to higher HbA1c, albumin excretion rate, C-reactive protein, systolic blood pressure, as well as TNF-alpha and IL-6 levels than those without retinopathy. The logistic regression revealed that the risk of NPDR was strongly dependent on TNF-alpha [(OR 4.01; 95%CI 2.01-7.96)]. TNF-alpha appears to be the most significant predictor among the analyzed parameters of damage to the eye apparatus. The early introduction of the TNF-alpha antagonists to the treatment of young patients with DM type 1 who show high serum activity of the TNF-alpha may prevent them from development of diabetic retinopathy.

Interleukin-12 and tumour necrosis factor-alpha equilibrium is a prerequisite for clinical course free from late complications in children with type 1 diabetes mellitus

The objective of the study was to analyse levels of IL-12 and TNF-alpha and relate the findings to the occurrence of microangiopathy in children with type 1 diabetes mellitus (DM). We examined a group of 123 children with type 1 DM. Serum levels of IL-12 and TNF-alpha were measured by an immunoenzymatic ELISA technique. TNF-alpha and IL-12 tended to be simultaneously present or absent in the sera of 50% of the children who had not developed complications, thus indicating a state of cytokine's equilibrium. Among the patients with an established retinopathy, two IL-12/TNF-alpha combinations were visible. Either a lack of detectable TNF-alpha was accompanied by measurable IL-12 serum concentrations or TNF-alpha incidence was associated with undetectable IL-12 values. Simultaneous lack of TNF-alpha and presence of IL-12 was associated with a better prognosis as these patients had a significantly lower albumin excretion rate. The state of equilibrium between TNF-alpha and IL-12 is beneficial in patients at early stages of the disease, prior to the occurrence of complications. Shifting the equilibrium towards TNF-alpha seems to promote late complications. It may suggest that a disharmony between pro- and anti-angiogenic function of these cytokines underlie the mechanism by which TNF-alpha and IL-12 shape the disease course.

Diabetes-associated macrovasculopathy: pathophysiology and pathogenesis

The complications associated with diabetic vasculopathy are commonly grouped into two categories: microvascular and macrovascular complications. In diabetes, macrovascular disease is the commonest cause of mortality and morbidity and is responsible for high incidence of vascular diseases such as stroke, myocardial infarction and peripheral vascular diseases. Macrovascular diseases are traditionally thought of as due to underlying obstructive atherosclerotic diseases affecting major arteries. Pathological changes of major blood vessels leading to functional and structural abnormalities in diabetic vessels include endothelial dysfunction, reduced vascular compliance and atherosclerosis. Besides, advanced glycation end product formation interacts with specific receptors that lead to overexpression of a range of cytokines. Haemodynamic pathways are activated in diabetes and are possibly amplified by concomitant systemic hypertension. Apart from these, hyperglycaemia, non-enzymatic glycosylation, lipid modulation, alteration of vasculature and growth factors activation contribute to development of diabetic vasculopathy. This review focuses on pathophysiology and pathogenesis of diabetes-associated macrovasculopathy.

Neutrophils and monocytes as potentially important sources of proinflammatory cytokines in diabetes

Neutrophils and monocytes play a central role in host defence. The invading leucocytes are capable of synthesizing and releasing a variety of proinflammatory mediators including cytokines. Given the importance of cytokines in the progression of chronic and acute inflammatory processes, we aimed to ascertain whether the release of interleukin (IL)-8, IL-1beta, tumour necrosis factor (TNF)-alpha and IL-1ra of neutrophils and monocytes was modified in diabetes. To this end, we measured the release of cytokines in suspensions of cell culture in basal and lipopolysaccharide (LPS)-stimulated conditions. In basal conditions, neutrophils of diabetics release 1.6, 3.2, 1.9 and 1.9-fold higher amounts of IL-8, IL-1beta, TNF-alpha and IL-1ra, respectively, than do healthy controls. Under our experimental conditions, this effect was more evident for neutrophils than for monocytes. Incremental cytokine production was also found to occur when neutrophils were stimulated with LPS. IL-8, IL-1beta and TNF-alpha increased, respectively, by 4.0, 1.7 and 2.8-fold. Although the effect was more marked for neutrophils, monocytes showed a tendency for increased cytokine production. The discovery of this increase in cytokines released by the neutrophils of diabetics contributes towards a clearer understanding of other deficiencies described for neutrophils in diabetes, such as the migration of neutrophils to inflammatory sites, phagocytes, release of lytic proteases, production of reactive oxygen species and apoptosis. The excessive production of cytokines may lead to inappropriate activation and tissue injury and even to increased susceptibility to invasive microorganisms. Thus, the increased responsiveness of neutrophils of diabetics demonstrated in this study may be considered part of the scenario of diabetes physiopathology.

IN SILICO MODELS OF ACUTE INFLAMMATION IN ANIMALS

Trauma and hemorrhagic shock elicit an acute inflammatory response, predisposing patients to sepsis, organ dysfunction, and death. Few approved therapies exist for these acute inflammatory states, mainly due to the complex interplay of interacting inflammatory and physiological elements working at multiple levels. Various animal models have been used to simulate these phenomena, but these models often do not replicate the clinical setting of multiple overlapping insults. Mathematical modeling of complex systems is an approach for understanding the interplay among biological interactions. We constructed a mathematical model using ordinary differential equations that encompass the dynamics of cells and cytokines of the acute inflammatory response, as well as global tissue dysfunction. The model was calibrated in C57Bl/6 mice subjected to (1) various doses of lipopolysaccharide (LPS) alone, (2) surgical trauma, and (3) surgery + hemorrhagic shock. We tested the model's predictive ability in scenarios on which it had not been trained, namely, (1) surgery +/- hemorrhagic shock + LPS given at times after the beginning of surgical instrumentation, and (2) surgery + hemorrhagic shock + bilateral femoral fracture. Software was created that facilitated fitting of the mathematical model to experimental data, as well as for simulation of experiments with various inflammatory challenges and associated variations (gene knockouts, inhibition of specific cytokines, etc.). Using this software, the C57Bl/6-specific model was recalibrated for inflammatory analyte data in CD14-/- mice and was used to elucidate altered features of inflammation in these animals. In other experiments, rats were subjected to surgical trauma +/- LPS or to bacterial infection via fibrin clots impregnated with various inocula of Escherichia coli. Mathematical modeling may provide insights into the complex dynamics of acute inflammation in a manner that can be tested in vivo using many fewer animals than has been possible previously.

Identical twins discordant for type 1 diabetes show a different pattern of in vitro CD56+ cell activation

BACKGROUND

Recent studies in animal models indicate a role for natural killer (NK) cells in the protection against type 1 diabetes. In humans, a reduction of NK cell numbers has been reported in identical twins discordant for type 1 diabetes, irrespective of whether they have the disease. Here we have tested whether the activation and expansion of human NK cells with lipopolysaccharide (LPS) reveals differences between these twins.

METHODS

Proportions of CD56(+) NK cells and T-cells and Va24Vb11(+) NK-T cells from diabetic and non-diabetic twins was assessed before and after activation using flow cytometry. NK receptor usage was monitored by PCR and flow cytometry.

RESULTS

The profile of the expressed Killer Cell immunoglobulin-like receptor (KIR) repertoire (using mRNA) in freshly isolated NK cells was identical in pairs of identical twins, despite marked variation among individual twins as well as controls. Basal numbers of CD56(+) and CD94(+) (CD3(-) and CD3(+)) cells and Valpha24(+)Vbeta11(+) NK-T cells were similarly strongly correlated between identical twins (p < 0.006 for all correlations). Following LPS stimulation, the pattern of KIR mRNA expression remained unaltered in twins and the proportion of NK cells and Valpha24(+)Vbeta11(+) NK-T cells remained correlated between pairs of twins. However, there was a significant reduction in the proportion of CD56(+) cells and CD94(+) cells (whether defined as CD3(-) or CD3(+)) responding to LPS in the diabetic compared to the non-diabetic twin (p = 0.031 and 0.025, respectively).

CONCLUSION

This reduction in NK cell expansion in response to LPS in patients with type 1 diabetes is consistent with a non-genetically determined alteration in the innate immune response either predisposing to or resulting from the disease.

MCP-1 and MIP-2 expression and production in BB diabetic rat: effect of chronic hypoxia

Type 1 (insulin-dependent) diabetes mellitus is an autoimmune disease characterized by the failure to synthesize or secrete insulin, and diabetics are likely to suffer complications that include kidney and heart disease, as well as loss of sight, angiopathy, tissue hypoxia, reduction in organ blood flow, impaired wound healing, respiratory infections, arteriosclerosis, etc., thus diabetes very closely resembles a state of chronic hypoxia. It is now well recognized that hypoxia is an important environmental stimulus capable of modulating the expression of many genes involved in energy metabolism. The diabetic metabolic stress resulting from impaired energy metabolism, which produce altered production of inflammatory mediators, may increase the risk of oxidative injury. The aim was to investigate whether production of MIP-2 and MCP-1 are implicated in the pathogenesis of diabetes, and if the regulatory effects of these chemokines are affected by hypoxia. Two groups of rats, diabetic and non-diabetic, were kept in normoxic room air conditions or subjected to chronic hypoxia. Expression and production of chemokines were measured by RT-PCR and ELISA assay. In diabetic rats, we found a marked increase of MCP-1 when compared with non-diabetic rats (783.5+/- 49 versus 461.9 +/- 27), while no significant differences were detected for MIP-2 levels. Hypoxia selectively modulated chemokines production, since MCP-1 expression and production was up-regulated in the diabetic groups (783.5+/- 49 versus 461.9+/- 27), but down-regulated MIP-2 expression and production (87.8+/- 23 versus 522.1+/- 72). Our data point to MCP-1 and MIP-2 as important components in the pathophysiology of diabetes, and hypoxia is an important and potent environmental stimulus capable of modulating the expression and production of these chemokines.

THE ACUTE INFLAMMATORY RESPONSE IN DIVERSE SHOCK STATES

A poorly controlled acute inflammatory response can lead to organ dysfunction and death. Severe systemic inflammation can be induced and perpetuated by diverse insults such as the administration of toxic bacterial products (e.g., endotoxin), traumatic injury, and hemorrhage. Here, we probe whether these varied shock states can be explained by a universal inflammatory system that is initiated through different means and, once initiated, follows a course specified by the cellular and molecular mechanisms of the immune and endocrine systems. To examine this question, we developed a mathematical model incorporating major elements of the acute inflammatory response in C57Bl/6 mice, using input from experimental data. We found that a single model with different initiators including the autonomic system could describe the response to various insults. This model was able to predict a dose range of endotoxin at which mice would die despite having been calibrated only in nonlethal inflammatory paradigms. These results show that the complex biology of inflammation can be modeled and supports the hypothesis that shock states induced by a range of physiologic challenges could arise from a universal response that is differently initiated and modulated.

Responses of Black and White Skin to Solar-Simulating Radiation: Differences in DNA Photodamage, Infiltrating Neutrophils, Proteolytic Enzymes Induced, Keratinocyte Activation, and IL-10 Expression

Black skin is more resistant to the deleterious effects of ultraviolet radiation than white skin. A higher melanin content and a different melanosomal dispersion pattern in the epidermis are thought to be responsible for this. Our purpose was to compare skin responses in black and white skin following exposure to solar-simulating radiation (SSR) to further investigate the photoprotective properties of black skin. Six volunteers of skin phototype I-III (white) were exposed to (doses measured directly with a Waldmann UV detector device) 12,000-18,000 mJ per cm2 (2 MED) of SSR and compared with six volunteers of skin phototype VI (black) exposed to 18,000 mJ per cm2 (<1 MED) of SSR. The presence and distribution of skin pigment, DNA photodamage, infiltrating neutrophils, photoaging associated proteolytic enzymes, keratinocyte activation, and the source of interleukin 10 (IL-10) in skin biopsies taken before and after exposure were studied. In all white skinned subjects, 12,000-18,000 mJ per cm2 of SSR induced DNA damage in epidermal and dermal cells, an influx of neutrophils, active proteolytic enzymes, and diffuse keratinocyte activation. Additionally, in three of the white skinned volunteers IL-10 positive neutrophils were found to infiltrate the epidermis. Except for DNA damage in the supra basal epidermis, none of these changes was found in black skinned subjects. Increased skin pigmentation appears to be primarily responsible for the observed differences in skin responses. Our data could provide an explanation as to why black skin is less susceptible to sunburn, photoaging, and skin carcinogenesis.

The involvement of T lymphocytes in the pathogenesis of endometriotic tissues overgrowth in women with endometriosis

BACKGROUND

Endometriosis, uncontrolled proliferation of ectopic and eutopic endometriotic tissues, is common in women at reproductive age, and may affect fertility. The role of macrophages in the pathogenesis is well proved, but engagement of T cells in the pathogenesis of endometriosis is a matter of controversy.

AIMS

T-cell involvement in the pathogenesis of endometriosis was the objective of our study performed on women aged 24-46 years with diagnosed endometriosis. All the patients that were studied underwent diagnostic laparoscopy.

METHODS

We evaluated the distribution of T-lymphocyte subpopulations in peripheral blood (PB), peritoneal fluid (PF) and in endometriotic tissues (ET), as well as cytokines [interleukin (IL)-2, IL-4, IL-10, IL-12, interferon (IFN)-gamma] production by peripheral blood lymphocytes. IFN-gamma, tumor necrosis factor (TNF)-alpha, IL-4 and IL-6 were investigated for their intracellular presence. The experiments were carried out before and after 6 months treatment with the GnRH-Analogous Goserelin (Zeneca Pharmaceuticals). The number of performed investigations is presented. Statistical analysis was performed using Statistica/Win 5.0 software and Student's t-test, the paired Student t-test and Fisher's exact test when appropriate.

RESULTS

We have compared the lymphocyte subset re-distribution with regard to the American Fertility Society (AFS) stages and scores, but no differences were observed. The significant increase in CD4:CD8 ratio, the decrease in the number of natural killer (NK) cells in PB and the decrease in CD4:CD8 ratio in PF and ET of women with endometriosis was noted. The diminished IFN-gamma secretion by phytohemagglutinim (PHA)-stimulated lymphocytes in vitro derived from women with endometriosis and increased IL-4 production may be responsible for defective immunosurveillance against overgrowth of endometriotic tissues. The diminished NK cells number in PB of women with endometriosis argues for such a hypothesis. The increased deposits of proinflammatory IL-6 and TNF-alpha in the T lymphocytes of women with endometriosis may be related to T-regulatory lymphocyte function and their inability to suppress cell proliferation in endometriosis. GnRH-Analogous Goserelin treatment normalises cytokine production and induces patient recovery.

CONCLUSIONS

The significant functional and phenotypic differences between the lymphocytes from healthy women and women with endometriosis were noted. The diminished IFN-gamma production in relation to decreased NK cells number and the increased IL-4 production before the treatment and normalisation after the treatment suggest the involvement of the deregulated T-cell system in the growth stimulation and recruitment of endometriotic cells. The increased CD4:CD8 ratio, IL-6, TNF-alpha deposits and diminished anti-inflammatory IL-10 production by lymphocytes may participate in the pathogenesis of endometriosis, and may secondarily affect the monocyte/macrophage function.

Redox- and oxidant-mediated regulation of interleukin-10: an anti-inflammatory, antioxidant cytokine?

Reduction-oxidation (redox) state constitutes such a potential signaling mechanism for the regulation of an inflammatory signal associated with oxidative stress. Interleukin (IL)-10 has recently emerged as an anti-inflammatory cytokine with antioxidant properties. Interestingly, redox- and oxidant-mediated pathways positively and/or negatively regulate the expression, distribution, and functional properties of IL-10, thus, allowing the evolution of what is known as an anti-inflammatory redox-oxidant revolving axis. This axis is directly involved in regulating phosphorylation mechanisms, which eventually control gene expression and the biosynthesis of oxidative stress-related cofactors, such as reactive species and inflammatory cytokines. The association between IL-10, an anti-inflammatory antioxidant, with redox- and oxidant-related pathways governing the regulation of inflammatory and closely dependent processes is thereafter discussed.