Expression of the adhesion molecules ICAM-1, VCAM-1, LFA-1 and VLA-4 in the skin is modulated in progressing stages of chronic venous insufficiency

Identifying Key Drivers in the Pathogenesis of Martorell Hypertensive Ischaemic Leg Ulcer: A Comparative Analysis with Chronic Venous Leg Ulcer

Martorell hypertensive ischaemic leg ulcer (Martorell HYTILU) is a rare but significant cause of distal leg ulcers. Although hypertension and diabetes are known factors in its development, the precise pathogenesis of Martorell HYTILU remains elusive. To reach a better understanding of Martorell HYTILU, transcriptomic analysis was conducted through RNA sequencing and immunohistochemical comparison of Martorell HYTILU (n = 17) with chronic venous ulcers (n = 4) and healthy skin (n = 4). Gene expression analysis showed a marked activation of immune-related pathways in both Martorell HYTILU and chronic venous ulcers compared with healthy skin. Notably, neutrophil activity was substantially higher in Martorell HYTILU. While pathway analysis revealed a mild downregulation of several immune pathways in Martorell HYTILU compared with chronic venous ulcers, keratinization, cornification, and epidermis development were significantly upregulated in Martorell HYTILU. Additionally, STAC2, a gene encoding for a protein promoting the expression of the calcium channel Cav1.1, was significantly upregulated in Martorell HYTILU and was detected perivascularly in situ (Martorell HYTILU n = 24; chronic venous ulcers n = 9, healthy skin n = 11). The high expression of STAC2 in Martorell HYTILU suggests that increased calcium influx plays an important role in the pathogenesis of the disease. Consequently, calcium channel antagonists could be a promising treatment avenue for Martorell HYTILU.

Hyperbaric Oxygen Therapy Reduces Oxidative Stress and Inflammation, and Increases Growth Factors Favouring the Healing Process of Diabetic Wounds

Hyperbaric oxygen therapy (HBOT) is the clinical application of oxygen at pressures higher than atmospheric pressure. HBOT has been effectively used to manage diverse clinical pathologies, such as non-healing diabetic ulcers. The aim of the present study was to analyse the effects of HBOT on the plasma oxidative and inflammation biomarkers and growth factors in patients with chronic diabetic wounds. The participants received 20 HBOT sessions (five sessions/week), and blood samples were obtained at sessions 1, 5 and 20, before and 2 h after the HBOT. An additional (control) blood sample was collected 28 days after wound recovery. No significant differences were evident in haematological parameters, whereas the biochemical parameters progressively decreased, which was significant for creatine phosphokinase (CPK) and aspartate aminotransferase (AST). The pro-inflammatory mediators, tumour necrosis factor alpha (TNF-α) and interleukin 1β (IL-1β), progressively decreased throughout the treatments. Biomarkers of oxidative stress--plasma protein levels of catalase, extracellular superoxide dismutase, myeloperoxidase, xanthine oxidase, malondialdehyde (MDA) levels and protein carbonyls--were reduced in accordance with wound healing. Plasma levels of growth factors--platelet-derived growth factor (PDFG), transforming growth factor β (TGF-β) and hypoxia-inducible factor 1-alpha (HIF-1α)-- were increased as a consequence of HBOT and reduced 28 days after complete wound healing, whereas matrix metallopeptidase 9 (MMP9) progressively decreased with the HBOT. In conclusion, HBOT reduced oxidative and pro-inflammatory mediators, and may participate in activating healing, angiogenesis and vascular tone regulation by increasing the release of growth factors.

Narrative Review of the Pathogenesis of Stasis Dermatitis: An Inflammatory Skin Manifestation of Venous Hypertension

INTRODUCTION

Stasis dermatitis (SD), also known as venous dermatitis, is a form of inflammatory dermatitis of the lower extremities that typically occurs in older individuals and represents a cutaneous manifestation of venous hypertension. Venous hypertension (also known as sustained ambulatory venous pressure) is most often due to retrograde blood flow, which occurs due to calf muscle pump failure. This failure is most commonly secondary to incompetent venous valves, valve destruction, or obstruction of the venous system. Many of the common symptoms associated with SD are caused by inflammatory processes.

METHODS

This review summarizes the pathogenesis and key role of inflammation in SD by reviewing inflammatory biomarkers associated with SD. The literature was selected though a high-level PubMed search focusing on keywords relating to inflammation associated with SD.

RESULTS

Venous reflux at the lower extremities causes venous hypertension, which leads to chronic venous insufficiency. High venous pressure due to venous hypertension promotes the local accumulation and extravasation of inflammatory cells across the vascular endothelium. Leukocyte trapping in the microcirculation and perivascular space is associated with trophic skin changes. Cell adhesion molecules are linked with the perpetuated influx of activated leukocytes into inflammatory sites. Here, inflammatory cells may influence the remodeling of the extracellular matrix by inducing the secretion of proteinases such as matrix metalloproteinases (MMPs). The increased expression of MMPs is associated with the formation of venous leg ulcers and lesions. Phosphodiesterase 4 activity has also been shown to be elevated in individuals with inflammatory dermatoses compared to healthy individuals.

DISCUSSION

Because inflammation is a key driver of the signs and symptoms of SD, several of the highlighted biomarkers of inflammation represent potential opportunities to target and interrupt molecular pathways of cutaneous inflammation and, therefore, remediate the signs and symptoms of SD.

CONCLUSION

Understanding the pathogenesis of SD may help clinicians identify drivers of inflammation to use as potential targets for the development of new treatment options.

Association of IL-4 with pachychoroid neovasculopathy

The purpose of this study was to identify the inflammatory cytokines that were associated with pachychoroid neovasculopathy (PNV). Seventy-five eyes of 75 patients with PNV, 145 eyes of 145 patients with neovascular age-related macular degeneration without pachyvessels, and 150 eyes of 150 normal subjects were examined for the levels of intraocular cytokines. In eyes with PNV, the levels of IL-1α, IL-1β, IL-2, IL-4, IL-10, and VEGF were significantly higher than that of the controls. Logistic regression analysis showed that the highest association with the pachyvessels was found for IL-4, IL-2, and IL-1α. In eyes with PNV, the levels of IL-4, IL-2, IL-5, IL-13, IL-1α, and IL-1β were significantly higher in eyes with both increased choroidal thickness and choroidal vessel diameter. The strongest correlation with the choroidal thickness and vessel diameter was observed for IL-4. In PNV eyes with polypoidal lesions, the levels of IL-4, IL-17, and TNFβ were significantly correlated with the number of polypoidal lesions. Of these cytokines, IL-4 was especially associated with the thickness of the choroidal vessels and the formation of polypoidal lesions. We conclude that IL-4 is most likely involved in establishing the clinical characteristics of PNV and polypoidal vascular remodeling.

Stasis Dermatitis: An Overview of Its Clinical Presentation, Pathogenesis, and Management

Stasis dermatitis is a chronic inflammatory skin disease of the lower extremities. It typically occurs in older individuals and is the cutaneous manifestation of venous hypertension caused by venous reflux. Such retrograde venous blood flow is the result of incompetent venous valves, valve destruction, or venous obstruction. Stasis dermatitis is eczematous. The associated impairment of venous valves may cause swelling of the legs, leading to serious conditions including venous ulcerations. Diagnosis can be challenging because of its clinical resemblance to other skin conditions and poor clinical recognition by physicians. The cornerstones of stasis dermatitis treatment are compression therapy to ameliorate pain and swelling, topical treatments to alleviate secondary skin changes, and interventional treatment options to correct the underlying causes of venous reflux. Given the central role of inflammation of the lower extremities in driving the cutaneous changes characteristic of stasis dermatitis, new therapeutic approaches that target the inflammation are under clinical evaluation in patients with stasis dermatitis.

Transcriptomic Profiling of Femoral Veins in Deep Vein Thrombosis in a Porcine Model

Deep vein thrombosis (DVT) is a severe disease affecting the human venous system, accompanied by high morbidity and mortality rates caused by early and late complications. The study aimed at analyzing the changes in the transcriptome of the femoral vein caused by DVT in the porcine model based on the formation of the thrombus in vivo. The study was performed on 11 castrated male pigs: A thrombus was formed in each left femoral vein in six animals; the remaining five served as a control group. Total RNA was isolated from the left femoral veins of the experimental and control animals. High-throughput RNA sequencing was used to analyze the global changes in the transcriptome of veins with induced DVT. Applied multistep bioinformatics revealed 1474 differentially expressed genes (DEGs): 1019 upregulated and 455 downregulated. Functional Gene Ontology annotated 1220 of DEGs into 225 biological processes, 30 molecular functions and 40 cellular components categories. KEGG analysis disclosed TNF, NF-κB and apoptosis pathways’ overexpression in DVT samples. A thorough analysis of the detected DEGs indicated that a dysregulated inflammatory response and disturbed balance between clotting and anti-clotting factors play a crucial role in the process of DVT.

Venous overload choroidopathy: A hypothetical framework for central serous chorioretinopathy and allied disorders

In central serous chorioretinopathy (CSC), the macula is detached because of fluid leakage at the level of the retinal pigment epithelium. The fluid appears to originate from choroidal vascular hyperpermeability, but the etiology for the fluid is controversial. The choroidal vascular findings as elucidated by recent optical coherence tomography (OCT) and wide-field indocyanine green (ICG) angiographic evaluation show eyes with CSC have many of the same venous patterns that are found in eyes following occlusion of the vortex veins or carotid cavernous sinus fistulas (CCSF). The eyes show delayed choroidal filling, dilated veins, intervortex venous anastomoses, and choroidal vascular hyperpermeability. While patients with occlusion of the vortex veins or CCSF have extraocular abnormalities accounting for the venous outflow problems, eyes with CSC appear to have venous outflow abnormalities as an intrinsic phenomenon. Control of venous outflow from the eye involves a Starling resistor effect, which appears to be abnormal in CSC. Similar choroidal vascular abnormalities have been found in peripapillary pachychoroid syndrome. However, peripapillary pachychoroid syndrome has intervortex venous anastomoses located in the peripapillary region while in CSC these are seen to be located in the macular region. Spaceflight associated neuro-ocular syndrome appears to share many of the pathophysiologic problems of abnormal venous outflow from the choroid along with a host of associated abnormalities. These diseases vary according to their underlying etiologies but are linked by the venous decompensation in the choroid that leads to significant vision loss. Choroidal venous overload provides a unifying concept and theory for an improved understanding of the pathophysiology and classification of a group of diseases to a greater extent than previous proposals.

Unlocking mammalian regeneration through hypoxia inducible factor one alpha signaling

Historically, the field of regenerative medicine has aimed to heal damaged tissue through the use of biomaterials scaffolds or delivery of foreign progenitor cells. Despite 30 years of research, however, translation and commercialization of these techniques has been limited. To enable mammalian regeneration, a more practical approach may instead be to develop therapies that evoke endogenous processes reminiscent of those seen in innate regenerators. Recently, investigations into tadpole tail regrowth, zebrafish limb restoration, and the super-healing Murphy Roths Large (MRL) mouse strain, have identified ancient oxygen-sensing pathways as a possible target to achieve this goal. Specifically, upregulation of the transcription factor, hypoxia-inducible factor one alpha (HIF-1α) has been shown to modulate cell metabolism and plasticity, as well as inflammation and tissue remodeling, possibly priming injuries for regeneration. Since HIF-1α signaling is conserved across species, environmental or pharmacological manipulation of oxygen-dependent pathways may elicit a regenerative response in non-healing mammals. In this review, we will explore the emerging role of HIF-1α in mammalian healing and regeneration, as well as attempts to modulate protein stability through hyperbaric oxygen treatment, intermittent hypoxia therapy, and pharmacological targeting. We believe that these therapies could breathe new life into the field of regenerative medicine.

Therapeutic Effects of Hyperbaric Oxygen in the Process of Wound Healing

Chronic and non-healing wounds, especially diabetic foot ulcers and radiation injuries, imply remarkable morbidity with a significant effect on the quality of life and a high sanitary cost. The management of these wounds requires complex actions such as surgical debris, antibiotic treatment, dressings and even revascularization. These wounds are characterized by poor oxygen supply resulting in inadequate oxygenation of the affected tissue. The adjuvant treatment with hyperbaric oxygen therapy (HBOT) may increase tissue oxygenation favoring the healing of wounds which do not respond to the usual clinical care. The increase in the partial pressure of oxygen contributes to cover the energy demands necessary for the healing process and reduces the incidence of infections. Moreover, the increase in oxygen leads to the production of reactive species with hormetic activity, acting on signaling pathways that modulate the synthesis of inflammation mediators, antioxidants and growth factors which can contribute to the healing process. Studies performed with cell cultures and in animal models seem to demonstrate the beneficial effects of HBOT. However, clinical trials do not show such conclusive results; thus, additional randomized placebo-controlled studies are necessary to determine the real efficacy of HBOT and the mechanism of action for various types of wounds.

Reactive Oxygen Species and NOX Enzymes Are Emerging as Key Players in Cutaneous Wound Repair

Our understanding of the role of oxygen in cell physiology has evolved from its long-recognized importance as an essential factor in oxidative metabolism to its recognition as an important player in cell signaling. With regard to the latter, oxygen is needed for the generation of reactive oxygen species (ROS), which regulate a number of different cellular functions including differentiation, proliferation, apoptosis, migration, and contraction. Data specifically concerning the role of ROS-dependent signaling in cutaneous wound repair are very limited, especially regarding wound contraction. In this review we provide an overview of the current literature on the role of molecular and reactive oxygen in the physiology of wound repair as well as in the pathophysiology and therapy of chronic wounds, especially under ischemic and hyperglycemic conditions.

Post-reconstruction dermatitis of the breast

BACKGROUND

Approximately one-third of women diagnosed with breast cancer undergo mastectomy with subsequent implant-based or autogenous tissue-based reconstruction. Potential complications include infection, capsular contracture, and leak or rupture of implants with necessity for explantation. Skin rashes are infrequently described complications of patients who undergo mastectomy with or without reconstruction.

METHODS

A retrospective analysis of breast cancer patients referred to the Dermatology Service for diagnosis and management of a rash post-mastectomy and expander or implant placement or transverse rectus abdominis myocutaneous (TRAM) flap reconstruction was performed. Parameters studied included reconstruction types, time to onset, clinical presentation, associated symptoms, results of microbiologic studies, management, and outcome.

RESULTS

We describe 21 patients who developed a rash on the skin overlying a breast reconstruction. Average time to onset was 25.7 months after expander placement or TRAM flap reconstruction. Clinical presentations included macules and papules or scaly, erythematous patches and plaques. Five patients had cultures of the rash, which were all negative. Skin biopsy was relatively contraindicated in areas of skin tension, and was reserved for non-responding eruptions. Treatments included topical corticosteroids and topical antibiotics, which resulted in complete or partial responses in all patients with documented follow-ups.

CONCLUSION

Our findings suggest that tension and post-surgical factors play a causal role in this hitherto undescribed entity: "post-reconstruction dermatitis of the breast." This is a manageable condition that develops weeks to years following breast reconstruction. Topical corticosteroids and antibiotics result in restoration of skin barrier integrity and decreased secondary infection.

Effects of a novel NADPH oxidase inhibitor (S42909) on wound healing in an experimental ischemic excisional skin model

Chronic wounds are a serious healthcare problem. As non-healing wounds involve continuous pathologic inflammatory stage, research is focused on anti-inflammatory treatments. Our objective was to analyze the effect of S42909, a potent NADPH oxidase inhibitor activity, with vascular anti-inflammatory properties. An ischemic rabbit ear ulcer model (24 New Zealand white rabbits) was used to evaluate the reepithelialization/contraction areas, anti-/pro-inflammatory cytokines mRNA (TGF-β1/IL-10/IFN-γ/VEGF) by qRT-PCR, collagen I/III deposition, and neovascularization (TGF-β1/VEGF) by morphological and immunohistochemical analyses. Three different doses were administered by gavage for 2 weeks: 10 and 30 mg/kg/d in self-microemulsion drug delivery system (SMEDDS) and 100 mg/kg/d in arabic gum. Each vehicle was used as control. No signs of infection or necrosis were found. Reepithelialization was almost complete whatever the groups reaching 95% at the dose of 100 mg/kg. Wound contraction was significantly reduced in all S42909-treated groups. A significant increase in anti-inflammatory cytokines TGF-β1 mRNA and IL-10 mRNA was observed at the dose of 100 and 30 mg/kg/d, respectively. No changes were observed in pro-inflammatory factors INF-γ and VEGF mRNA. Ischemic skin wound areas had scarce expression of collagen I/III and showed rich glycosaminoglycans content. Treatment increased the collagen deposition and TGF-β1 protein expression and decreased glycosaminoglycan content dose dependently; however, no effect in VEGF was appreciated. Therefore, our results indicate that S42909 improved healing process by dampening excessive inflammation and facilitating collagen deposition without wound contraction phenomena. S42909 might be a promising therapy to treat chronic wounds as venous leg ulcers.

Inflammation in Chronic Wounds

Non-healing chronic wounds present a major biological, psychological, social, and financial burden on both individual patients and the broader health system. Pathologically extensive inflammation plays a major role in the disruption of the normal healing cascade. The causes of chronic wounds (venous, arterial, pressure, and diabetic ulcers) can be examined through a juxtaposition of normal healing and the rogue inflammatory response created by the common components within chronic wounds (ageing, hypoxia, ischaemia-reperfusion injury, and bacterial colonisation). Wound bed care through debridement, dressings, and antibiotics currently form the basic mode of treatment. Despite recent setbacks, pharmaceutical adjuncts form an interesting area of research.

Dermal Changes in the Lower Leg Skin of Patients With Venous Hypertension

Patients with chronic venous disease may develop characteristic changes in the skin of the lower limb known as lipodermatosclerosis (LDS). The affected skin becomes indurated and pigmented and often ulcerates. The degree of induration associated with LDS correlates directly with ulcer formation and leads to a subsequent delayed rate of healing. However, there is limited information regarding the cellular and molecular events that lead from venous dysfunction to LDS development. This article reviews the current knowledge of the clinical progression of chronic venous disease, summarizing the histological findings from these authors’ laboratory and other studies on LDS, and offers possible mechanisms to explain the fibrotic changes associated with this condition.

Secretion of wound healing mediators by single and bi-layer skin substitutes

Limitations of current treatments for skin loss caused by major injuries leads to the use of skin substitutes. It is assumed that secretion of wound healing mediators by these skin substitutes plays a role in treating skin loss. In our previous study, single layer keratinocytes (SK), single layer fibroblast (SF) and bilayer (BL; containing keratinocytes and fibroblasts layers) skin substitutes were fabricated using fibrin that had shown potential to heal wounds in preclinical studies. This study aimed to quantify the secretion of wound healing mediators, and compare between single and bi-layer skin substitutes. Skin samples were digested to harvest fibroblasts and keratinocytes, and expanded to obtain sufficient cells for the construction of skin substitutes. Acellular fibrin (AF) construct was used as control. Substitutes i.e. AF, SK, SF and BL were cultured for 2 days, and culture supernatant was collected to analyze secretion of wound healing mediators via multiplex ELISA. Among 19 wound healing mediators tested, BL substitute secreted significantly higher amounts of CXCL1 and GCSF compared to SF and AF substitute but this was not significant with respect to SK substitute. The BL substitute also secreted significantly higher amounts of CXCL5 and IL-6 compared to other substitutes. In contrast, the SK substitute secreted significantly higher amounts of VCAM-1 compared to other substitutes. However, all three skin substitutes also secreted CCL2, CCL5, CCL11, GM-CSF, IL8, IL-1α, TNF-α, ICAM-1, FGF-β, TGF-β, HGF, VEGF-α and PDGF-BB factors, but no significant difference was seen. Secretion of these mediators after transplantation may play a significant role in promoting wound healing process for the treatment of skin loss.

Provisional Matrix Deposition in Hemostasis and Venous Insufficiency: Tissue Preconditioning for Nonhealing Venous Ulcers

Significance: Chronic wounds represent a major burden on global healthcare systems and reduce the quality of life of those affected. Significant advances have been made in our understanding of the biochemistry of wound healing progression. However, knowledge regarding the specific molecular processes influencing chronic wound formation and persistence remains limited. Recent Advances: Generally, healing of acute wounds begins with hemostasis and the deposition of a plasma-derived provisional matrix into the wound. The deposition of plasma matrix proteins is known to occur around the microvasculature of the lower limb as a result of venous insufficiency. This appears to alter limb cutaneous tissue physiology and consequently drives the tissue into a 'preconditioned' state that negatively influences the response to wounding. Critical Issues: Processes, such as oxygen and nutrient suppression, edema, inflammatory cell trapping/extravasation, diffuse inflammation, and tissue necrosis are thought to contribute to the advent of a chronic wound. Healing of the wound then becomes difficult in the context of an internally injured limb. Thus, interventions and therapies for promoting healing of the limb is a growing area of interest. For venous ulcers, treatment using compression bandaging encourages venous return and improves healing processes within the limb, critically however, once treatment concludes ulcers often reoccur. Future Directions: Improved understanding of the composition and role of pericapillary matrix deposits in facilitating internal limb injury and subsequent development of chronic wounds will be critical for informing and enhancing current best practice therapies and preventative action in the wound care field.

Assessment of multifunctional contrast agent probes in neuroimaging: Implications of nanopharmaceutical therapeutic interventions

Recently, a clear association has been found between the progression of motor neurodegenerative disorders (MNDs) and carotid atherosclerosis. Significant vascular abnormalities with arterial hypertension were shown to be in patients with familial antecedents of MNDs. The main scope of this work is to explore the feasibility of recently developed integrated nano-based imaging modalities for the assessment of early diagnosis of the inflammatory processes associated with the neurological disorder syndromes, with the implication of recently developed nanopharmaceutical therapeutic interventions.

Evidence that venous hypertension causes stasis dermatitis

A clinical model to examine the hypothesis that venous hypertension of the lower leg per se can cause lower leg stasis dermatitis is described. To prove this concept, we retrospectively studied a consecutive series of 38 patients with lower leg dermatitis who underwent phlebological examination at our consultation over a period of four years. Among those patients who had an insufficiency of the superficial veins only, without insufficiency of the deep veins, 22 had undergone patch testing to common allergens in phlebology. We found 10 patients with a stasis dermatitis of the lower leg and an incompetent great saphenous vein, six of whom had no detectable contact sensitization at all and another four exclusively to phlebologically irrelevant substances, e.g. nickel, cobalt, chromate or epoxid resin. All these 10 patients showed long saphenous vein incompetence from the groin to the medial aspect of the leg. All were operated by classical flush ligation and saphenectomy. Lower leg dermatitis healed in all 10 patients within 8–12 weeks and no recurrence was observed (1 year follow-up). These results support clinical experience that venous hypertension alone indeed can cause lower leg dermatitis.

Varicose veins show enhanced chemokine expression

OBJECTIVES

Leucocyte infiltration in the wall of varicose veins has been reported previously. This study was designed to investigate the expression of pro-inflammatory cytokines and chemokines in control and in patients with varicose veins and to test the effect of treating varicose vein patients with acetylsalicylic acid (ASA) on cytokine expression prior to removal of varices.

MATERIAL AND METHODS

Sections of vein were removed during operation from both patient groups, and ribonuclease protection assays (RPAs) were performed to assess the expression of chemokines. Group I included non-varicose saphenous veins from healthy patients undergoing amputation for trauma. Varicose veins were obtained from patients with primary varicose undergoing surgical treatment who received no drug (group II) or treatment with 300 mg day(-1) of ASA for 15 days before surgery (group III).

RESULTS

Non-varicose veins constitutively expressed low levels of monocyte-chemoattractant protein (MCP-1) and interleukin (IL)-8 mRNA. Varicose veins had a distinct chemokine expression pattern, since significant up-regulation of MCP-1 and IL-8 and a marked expression of IP-10, RANTES, MIP-1alpha and MIP-1beta mRNA were detected. Removal of the endothelium did not alter this pattern. Varicose veins obtained from patients treated with ASA showed a consistent decrease in chemokine expression, although it did not reach statistical significance.

CONCLUSIONS

Varicose veins showed increased expression of several chemokines compared to control veins. A non-significant reduction of activation was observed following treatment with ASA for 15 days.

Recent insights into the causes of chronic leg ulceration in venous diseases and implications on other types of chronic wounds

Venous ulceration represents the most prevalent form of difficult-to-heal wounds and these problematic wounds require a significant amount of healthcare resources for their treatment. In order to develop effective treatment regimens a clearer understanding of the underlying pathological processes that lead to skin breakdown is required. However, to date, most of these studies have tended to focus on describing the pathology of already-established ulcers. By bringing together relevant aspects of diverse disciplines such as inflammation, cardiovascular, and connective tissue biology, we aim to provide an insight into how circulatory abnormalities that are caused by the underlying disease etiology can induce local tissue inflammation resulting in tissue breakdown. Initially this results in internal tissue damage but if the underlying disease is not treated, the internal tissue damage can worsen and lead to open ulceration. This article discusses the cause-and-effect relationships between chronic venous insufficiency and venous ulceration, focusing particularly on the biological processes that lead from the underlying disease condition to overt ulceration. Available evidence also suggests that formation of pressure, diabetic foot and arterial ulcers, and ulcers as results of blood disorders, is also likely to share some of the same biological processes as venous ulcers.

Oxidative stress in chronic venous leg ulcers

Venous leg ulcers are common and cause considerable morbidity in the population. As healing may be slow or may never be achieved, ulcers create persistent and substantial demands on clinical resources. Great efforts have been made to accelerate tissue repair in chronic venous leg ulcers with limited success. This may at least be partly due to the limited knowledge on the microenvironment of chronic wounds. In fact, the tremendous impact of the microenvironmental conditions on the outcome of wound healing has increasingly become apparent. Oxidative stress as a consequence of an imbalance in the prooxidant-antioxidant homeostasis in chronic wounds is thought to drive a deleterious sequence of events finally resulting in the nonhealing state. The majority of reactive oxygen species are most likely released by neutrophils and macrophages and to an unknown extent from resident fibroblasts and endothelial cells. As the inflammatory phase does not resolve in chronic wounds, the load of reactive oxygen species persists over a long period of time with subsequent continuous damage and perpetuation of the inflammation. In this article, we will critically discuss recent findings that support the role of oxidative stress in the pathophysiology of nonhealing chronic venous leg ulcers.

Chronic venous insufficiency - a potential trigger for localized scleroderma

Localized scleroderma is a cutaneous disease that is characterized by an initial inflammatory response, followed by sclerosis of the skin. The cause of localized scleroderma has not yet been determined. Seifarth et al. reported two cases of localized scleroderma at sites of chronic venous insufficiency. We document here three more patients in whom localized scleroderma was located at insufficient veins. Treatment of underlying chronic venous insufficiency (CVI) leads to a substantial clinical improvement of scleroderma at the site of insufficient veins, but not elsewhere. Experimental data support the concept of chronic venous insufficiency creating a microenvironment, which may lead to localized scleroderma. Local hypoxaemia, which is present in CVI, induces the release of endothelium-derived cytokines, such as IL-1. Subsequently, expression of endothelial adhesion molecules and consequently leucocyte extravasation are induced. Infiltrating leucocytes secrete a number of inflammatory mediators, including transforming growth factor beta, which is a potent stimulus for collagen synthesis. Therefore, it may well be that CVI is a potential trigger factor for localized scleroderma. In addition, localized scleroderma may only develop if a certain amount of trigger factors are present - and resolves if one or more of the contributing factors (i.e. CVI) can be treated.

Microcirculation and Venous Ulcers: A Review

Recent histological and immunocytochemical analyses of venous leg ulcers suggest that lesions observed in the different stages of chronic venous insufficiency (CVI) may be related to an inflammatory process. This inflammatory process leads to fibrosclerotic remodeling of the skin and then to ulceration. The vascular network of the most superficial layers of the skin appears to be the target of the inflammatory reaction. Hemodynamic forces such as venous hypertension, circulatory stasis, and modified conditions of shear stress appear to play an important role in an inflammatory reaction accompanied by leukocyte activation which clinically leads to CVI: venous dermatitis and venous ulceration. The leukocyte activation is accompanied by the expression of integrins and by synthesis and release of many inflammatory molecules, including proteolytic enzymes, leukotrienes, prostaglandin, bradykinin, free oxygen radicals, cytokines, and possibly other classes of inflammatory mediators. The inflammatory reaction perpetuates itself, leading to liposclerotic skin and subcutaneous tissue remodeling. In light of the mechanisms of venous ulcer formation cited above, therapy in the future might be directed against leukocyte activation in order to diminish the magnitude of the inflammatory response. With this in mind, the attention of many investigators has been drawn to two different drugs with an anti-inflammatory effect: pentoxifylline and flavonoids.

Low recruitment of immune cells with increased expression of endothelial adhesion molecules in margins of the chronic diabetic foot ulcers

Diabetic foot skin close to an ulcer shows only a few infiltrating cells compared to nondiabetic inflamed tissues. Diabetes is characterized by thickened basement membrane of the blood arterioles and capillaries. This may affect the transcapillary transport of immune humoral factors and cells to the extravascular space. We analyzed by immunohistochemistry the phenotype and expression pattern of adhesion molecules on leukocyte, dermal fibroblast, and endothelial cells in diabetic foot ulcers. Although there was accumulation of granulocytes on the surface and superficial layers of the granulation tissue, rare perivascular granulocyte infiltrates in the dermis were seen. Moreover, lack of macrophage and CD3+ T cell infiltrates was observed. In contrast, there was increased intensity of CD1a staining of Langerhans cells in the epidermis and papillary dermis (p < 0.05). Fibroblasts revealed increased presence in the ulcer margins compared with normal skin (p < 0.05). Skin endothelial cells expressed stronger von Willebrand factor and E-selectin compared with normal skin (p < 0.05). Our study provides evidence that increased expression of endothelial cell adhesion molecules responsible for immunocyte extravasation is not associated with increased inflammatory cell infiltration of the ulcerated diabetic foot tissue. We suggest that the healing process of diabetic foot ulcers may be hampered by mechanisms decreasing accumulation of leukocytes. This implies that pharmacological or biological stimulation of leukocyte extravasation into the ulcer tissue should be tried.

Changes in Soluble Adhesion Molecules in Gingival Crevicular Fluid Following Periodontal Surgery

BACKGROUND

Inflammation of periodontal tissues during postoperative wound healing is mediated by cell surface adhesion molecules. Soluble forms of these antigens have also been identified and shown to be important in immunoregulatory processes, but have previously not been investigated during periodontal repair and regeneration. The present study has examined the presence and possible changes in soluble intercellular adhesion molecule-1 (sICAM-1; CD54) and lymphocyte function-associated antigen-3 (sLFA-3; CD58) in gingival crevical fluid (GCF) following periodontal surgery.

METHODS

GCF samples were collected from four groups: 1) a guided tissue regeneration (GTR) test; 2) a GTR control, at least one complete tooth unit away from the periodontal defect; 3) a conventional flap (CF) surgery; and 4) a crown lengthening (CL). Sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of sICAM-1 and sLFA-3 in the GCF samples.

RESULTS

A marked increase in GCF volumes was found in all sites after surgery, although a persistent increase was associated only with the period of membrane retention at the GTR test sites. In addition, sICAM-1 and sLFA-3 were found in the GCF of healthy as well as diseased sites prior to treatment and the total amounts of both increased transiently following surgical intervention, especially sLFA-3. However, the concentrations of these GCF components, particularly sICAM-1, tended to decrease.

CONCLUSIONS

The temporal decrease in the concentration of sICAM-1 and sLFA-3 in GCF may serve to enhance inflammatory reactions at surgically-treated periodontal sites, thereby limiting repair and regeneration in the periodontium. These soluble adhesion molecules may thereby be of potential therapeutic value and might also be useful markers for monitoring periodontal wound healing.

Causes of severe chronic venous insufficiency

A large number of adults in this country have some form of chronic venous insufficiency and a significant percentage of these have venous ulcers. The past decade has refined understanding of leukocyte-mediated injury and has elucidated the role of inflammatory processes in the dermal pathology of chronic venous insufficiency. Understanding of these pathologic cellular functions and molecular regulation of these processes is increasing.

Activated, not resting, platelets increase leukocyte rolling in murine skin utilizing a distinct set of adhesion molecules

Selectin-mediated tethering and rolling initiates the multi-step process of leukocyte extravasation which is crucial for the formation of an inflammatory infiltrate. We studied the impact of platelets on this process in the skin. Using intravital microscopy, we analyzed platelet interactions with cutaneous post-capillary venules of mouse ears and observed an increase in platelet rolling if platelets were activated (41.6+/-20.2% vs. 13.1+/-8.5% rolling of resting platelets). Experiments with P-selectin deficient mice and antibodies blocking either P-selectin, GPIIb/IIIa or GPIb showed that rolling depends on platelet PSGL-1 and GPIIb/IIIa on one hand, and endothelial P-selectin on the other. Next, formation of platelet-leukocyte aggregates was demonstrated by simultaneous observation of platelets and leukocytes in vivo utilizing a newly developed two-color technique. Aggregates increased overall leukocyte rolling (leukocytes alone: 27.4+/-11.2%, leukocytes with resting platelets: 25.3+/-10.2%, leukocytes with activated platelets 38.1+/-11.8%). To investigate if activated platelets may contribute to the pathogenesis of chronic cutaneous inflammation, platelet P-selectin expression was studied in 8 patients with psoriasis. A correlation between platelet P-selectin expression and disease severity was established. In summary, we show that activated, not resting, platelets increase leukocyte rolling in murine skin. This increased rolling is due to the aggregate formation of platelets with leukocytes. We also provide evidence for a potential role of this mechanism in the pathogenesis of chronic inflammatory skin diseases.

Pentoxifylline for treatment of venous leg ulcers: a systematic review

INTRODUCTION

Venous ulcers are usually treated with compression therapy, but, because this treatment may not be effective for some people, adjuvant therapy could be beneficial. We did a systematic review of randomised controlled trials that compared pentoxifylline (with and without compression treatment) with placebo, or other treatments, in patients with venous leg ulcers.

METHODS

We identified eight trials (547 adults), five of which compared pentoxifylline and compression with placebo and compression (n=445), and three of which compared pentoxifylline alone with placebo (102). Our main aim was to determine whether pentoxifylline, with or without compression, was effective in treatment of venous leg ulcers. Analysis was by intention to treat.

FINDINGS

Pentoxifylline was more effective than placebo in complete healing or substantial improvement of venous leg ulcers (relative risk 1.49, 95% CI 1.11-2.01). Pentoxifylline with compression was also more effective than placebo and compression in complete healing (1.30, 1.10-1.54). Patients taking pentoxifylline had no more adverse events than those on placebo (1.25, 0.87-1.80). The most frequent adverse event was mild gastrointestinal disturbance (43%).

INTERPRETATION

Our results suggest that pentoxifylline gives additional benefit to compression for venous leg ulcers, and is possibly effective for patients not receiving compression.

New advances in the understanding of the pathophysiology of chronic venous insufficiency

Chronic venous insufficiency (CVI) is inseparably linked to elevated venous pressure and is accompanied by vascular, dermal, and subcutaneous tissue damage and restructuring. Abundant evidence exists both in humans and in experimental models to suggest that the tissue damage may be initiated by generation of an inflammatory reaction. Inflammatory indicators include elevation of endothelial permeability; attachment of circulating leukocytes to the endothelium; infiltration of monocytes, lymphocytes, and mast cells into the connective tissue; and development of fibrotic tissue infiltrates and several molecular markers, such as growth factor or membrane adhesion molecule generation. Indicators of an inflammatory reaction are already detectable at early stages of CVI and may be involved in the development of primary venous valve dysfunction. One of the important questions is to identify trigger mechanisms for the inflammatory reaction in CVI. Current evidence suggests that, among several possible mechanisms (hypoxia, humoral stimulation), a shift in fluid shear stress from normal physiological levels and endothelial distension under the influence of elevated venous pressure may serve as trigger mechanisms for inflammation.