Most wounds heal in an orderly set of stages and in a predictable amount of time; those that do not are called chronic wounds (Moreo, 2005; Thomas et al., 2005). Wounds that do not heal within three months are considered chronic (Mustoe, 2005). Chronic wounds seem to be detained in one or more of the phases of wound healing (Snyder, 2005); for example, chronic wounds often remain in the inflammatory stage for too long (Snyder, 2005; Taylor et al., 2005). In acute wounds, there is a precise balance between production and degradation of molecules such as collagen; in chronic wounds this balance is lost and degradation plays too large a role (Edwards et al., 2004; Schönfelder et al., 2005). Superficial bullet wounds A wound is type of physical trauma wherein the skin is torn, cut or punctured (an open wound), or where blunt force trauma causes a contusion (a closed wound). ... Wound healing, or wound repair, is the bodys natural process of regenerating dermal and epidermal tissue. ... Inflammation is the first response of the immune system to infection or irritation and may be referred to as the innate cascade. ... In chemistry, a molecule is an aggregate of at least two atoms in a definite arrangement held together by special forces. ... Tropocollagen triple helix. ...

Chronic wounds may never heal or may take years to do so (Taylor et al., 2005). These wounds cause patients severe emotional and physical stress as well as creating a significant financial burden on patients and the whole healthcare system (Augustin and Maier, 2003; Crovetti et al., 2004; Halcón and Milkus, 2004) The factual accuracy of this article is disputed. ...

Acute and chronic wounds are at opposite ends of a spectrum of wound healing types that progress toward being healed at different rates (Moreo, 2005).

This patient has had these venous ulcers on both legs for 30 years. ...

Epidemiology

Chronic wounds mostly affect people over the age of 60 (Mustoe, 2004). The incidence is 0.78% of the population and the prevalence ranges from 0.18 to 0.32% (Crovetti et al., 2004). As the population ages, the number of chronic wounds is expected to rise (Crovetti et al., 2004; Moreo, 2005; Snyder, 2005; Supp and Boyce, 2005). The incidence of disease is defined as the number of new cases of disease occurring in a population during a defined time interval. ... The prevalence of a disease in a statistical population is defined as follows: Prevalence is useful because it is a measure of the commonality of disease. ... Old age consists of ages nearing the average life span of human beings, and thus the end of the human life cycle. ...

Types

The vast majority of chronic wounds can be classified into three categories: venous, diabetic, and pressure ulcers (Mustoe, 2004; Moreo, 2005) CW. A small number of wounds that do not fall into these categories may be due to causes such as radiation poisoning or ischemia (Mustoe, 2004). This article is about the disease that features high blood sugar. ... Bedsores, also called pressure sores or decubitus ulcers, are ulcers (sores) caused by prolonged pressure or rubbing on vulnerable areas of the body. ... Radiation poisoning, also called radiation sickness, is a form of damage to organic tissue due to excessive exposure to ionizing radiation. ... In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. ...

Venous ulcers

Venous ulcers, which usually occur in the legs, exist in about 70% to 90% of chronic wounds (Snyder, 2005) and mostly affect the elderly. They are thought to be due to venous hypertension caused by improper function of valves that exist in the veins which exist to prevent backflow of blood. Ischemia results and, combined with reperfusion injury, causes the tissue damage that leads to the wounds. Venous ulcers are wounds that are thought to occur due to improper functioning of valves in the veins usually of the legs. ... Vein - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. ... Reperfusion injury refers to damage to tissue caused when blood supply returns to the tissue after a period of ischemia. ...

Diabetic ulcers

Another major cause of chronic wounds, diabetes, is increasing in prevalence (Velander et al., 2004). Diabetics have a 15% higher risk for amputation than the general population (Snyder, 2005) due to chronic ulcers. Diabetes causes neuropathy, which inhibits the perception of pain (Snyder, 2005). Thus patients may not initially notice small wounds to legs and feet, and thus may fail to prevent infection and repeated injury (Moreo, 2005). Further, diabetes causes immune compromise (Snyder, 2005) and damage to small blood vessels, preventing adequate oxygenation of tissue, which can cause chronic wounds (Moreo, 2005). Pressure also plays a role in the formation of diabetic ulcers (Mustoe, 2004). Amputation is the removal of a body extremity by trauma or surgery. ... Diabetic neuropathies are neuropathic disorders that are associated with diabetes mellitus. ... PSYCHOLOGY In psychology and the cognitive sciences, perception is the process of acquiring, interpreting, selecting, and organizing sensory information. ... Pain is an unpleasant sensation which may be associated with actual or potential tissue damage and which may have physical and emotional components. ... Infection is also the title of an episode of the television series Babylon 5, and the English title of the Japanese film Kansen. ... Injury is damage or harm caused to the structure or function of the body caused by an outside agent or force, which may be physical or chemical. ...

Pressure ulcers

Another leading type of chronic wounds is pressure ulcers (Supp and Boyce, 2005), which usually occur in people with conditions such as paralysis that inhibit movement on areas that press against bones such as the heels, shoulder blades, and sacrum (Thomas et al., 2005; Wilhelmi and Neumeister, 2005). Pressure ulcers are caused by ischemia that occurs when pressure on the tissue is greater than the pressure in capillaries, and thus restricts blood flow into the area (Supp and Boyce, 2005; Wilhelmi and Neumeister, 2005). Muscle tissue, which needs more oxygen and nutrients than skin does, shows the worst effects from prolonged pressure (Wilhelmi and Neumeister, 2005). As in other chronic ulcers, reperfusion injury damages tissue (Mustoe, 2004). Paralysis is the complete loss of muscle function for one or more muscle groups. ... // Nutrients and the body A nutrient is any element or compound necessary for or contributing to an organisms metabolism, growth, or other functioning. ... A section of Human Skin In zootomy and dermatology, skin is an organ of the integumentary system made up of a layer of tissues that guard underlying muscles and organs. ...

Pain and chronic wounds

Chronic wound patients often report pain as dominant in their lives (Krasner, 1998) and the pain related to the wound should be handled as one of the main priorities in chronic wound management together with addressing the cause. Six out of 10 venous leg ulcer patients experience pain with their ulcer (Hofman et al., 1997), and similar trends is observed for other chronic wounds. Pain is an unpleasant sensation which may be associated with actual or potential tissue damage and which may have physical and emotional components. ...

Research, based on patient interviews and through patient diaries (Chase et al., 1997;Hyde et al., 1999;Krasner, 1998;Walshe, 1995), identified persistent pain (at night, at rest, and with activity) as the main problem for a patient with a chronic ulcer. Frustrations regarding ineffective analgesics and plans of care that they were unable to adhere to, were also identified. Identifying themes and concerns for patients with chronic ulcers must be based on patients’ own experiences, a paradigm in line with McCaffrey (McCaffrey, 1968) where she stated that “pain is what the patient says it is”. An analgesic (colloquially known as a painkiller) is any member of the diverse group of drugs used to relieve pain and to achieve analgesia. ... Compliance (or Adherence) in a medical context refers to a patient both agreeing to and then undergoing some part of their treatment program as advised by their doctor or other healthcare worker. ... Since the late 1960s, the word paradigm (IPA: ) has referred to a thought pattern in any scientific discipline or other epistemological context. ...

Contributing factors

In addition to poor circulation, neuropathy, and difficulty moving, factors that contribute to chronic wounds include systemic illnesses, age, and repeated trauma (Yaple, 2005). Comorbid ailments that may contribute to the formation of chronic wounds include vasculitis (an inflammation of blood vessels), immune suppression, pyoderma gangrenosum, and diseases that cause ischemia (Snyder, 2005). Immune suppression can be caused by illnesses or medical drugs used over a long period, for example steroids (Snyder, 2005). Emotional stress can also negatively affect the healing of a wound, possibly by raising blood pressure and levels of cortisol, which lowers immunity (Augustin and Maier, 2003). The circulatory system or cardiovascular system is the organ system which circulates blood around the body of most animals. ... In medicine, vasculitis (plural: vasculitides) is a group of diseases featuring inflammation of the wall of blood vessels. ... Immunosuppression is the medical suppression of the immune system. ... Oral medication A medication is a licenced drug taken to cure or reduce symptoms of an illness or medical condition. ... A steroid is a lipid characterized by a carbon skeleton with four fused rings. ... Stress (roughly the opposite of relaxation) is a medical term for a wide range of strong external stimuli, both physiological and psychological, which can cause a physiological response called the general adaptation syndrome, first described in 1936 by Hans Selye in the journal Nature. ... Blood pressure is the pressure exerted by the blood on the walls of the blood vessels. ... Cortisol is a corticosteroid hormone that is involved in the response to stress; it increases blood pressure and blood sugar levels and suppresses the immune system. ...

What appears to be a chronic wound may also be a malignancy; for example, cancerous tissue can grow until blood cannot reach the cells, and the tissue becomes an ulcer (Trent, 2003). Cancer, especially squamous cell carcinoma, may also form as the result of chronic wounds (Brem et al., 2004), probably due to repetitive tissue damage that stimulates rapid cell proliferation (Trent, 2003). When normal cells are damaged or old they undergo apoptosis; cancer cells, however, avoid apoptosis. ... When normal cells are damaged beyond repair, they are eliminated by apoptosis. ...

Another factor that may contribute to chronic wounds is old age (Mustoe, 2004). The skin of older people is more easily damaged, and older cells do not proliferate as fast and may not have an adequate stress response in terms of gene upregulation of stress-related proteins (Mustoe, 2004). In older cells, stress response genes are overexpressed when the cell is not stressed, but when it is, the expression of these proteins is not upregulated by as much as in younger cells (Mustoe, 2004). The term cell growth is used in two different ways in biology. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...

Comorbid factors that can lead to ischemia are especially likely to contribute to chronic wounds and include chronic fibrosis, atherosclerosis (Mustoe, 2004), edema (Moreo, 2005), sickle cell disease, and arterial insufficiency-related illnesses (Snyder, 2005). Fibrosis is the formation or development of excess fibrous connective tissue in an organ or tissue as a reparative or reactive process, as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue. ... ...

Repeated physical trauma plays a role in chronic wound formation by continually initiating the inflammatory cascade. The trauma may occur by accident, for example when a leg is repeatedly bumped against a wheelchair rest, or it may be due to intentional acts. Heroin users who lose venous access may resort to 'skin popping', or injecting the drug subcutaneously, which is highly damaging to tissue and frequently leads to chronic ulcers (Williams and Southern, 2005). Children who are repeatedly seen for a wound that does not heal are sometimes found to be victims of a parent with Munchausen syndrome by proxy, a disease in which the abuser may repeatedly inflict harm on the child in order to receive attention (Vennemann et al., 2005). In medicine, a trauma patient has suffered serious and life-threatening physical injury resulting in secondary complications such as shock, respiratory failure and death. ... Heroin or diacetylmorphine (INN) is a semi-synthetic opioid. ... The subcutis is the layer of tissue directly underlying the cutis. ... Munchausen syndrome is a form of psychological disorder known as a factitious disorder. ...

Pathophysiology

Chronic wounds may affect only the epidermis and dermis, or they may affect tissues all the way to the fascia (Crovetti et al., 2004). They may be formed originally by the same things that cause acute ones, such as surgery or accidental trauma (Moreo, 2005), or they may form as the result of systemic infection, vascular, immune, or nerve insufficiency, or comorbidities such as neoplasias or metabolic disorders (Crovetti et al., 2004). The reason a wound becomes chronic is that the body’s ability to deal with the damage is overwhelmed by factors such as repeated trauma, continued pressure, ischemia, or illness (Crovetti et al., 2004; Moreo, 2005). Epidermis is the outermost layer of the skin. ... The dermis is the layer of skin beneath the epidermis, that consists of connective tissue and cushions the body from stress and strain. ... Fascia is a specialized connective tissue layer which surrounds muscles, bones, and joints, providing support and protection and giving structure to the body. ... A typical modern surgical operation For other uses, see Surgery (disambiguation). ... Neoplasia (literally: new growth) is abnormal, disorganized growth in a tissue or organ, usually forming a distinct mass. ...

Though much progress has been accomplished in the study of chronic wounds lately, advances in the study of their healing have lagged behind expectations. This is partly due to the fact that animal studies are difficult because animals do not get chronic wounds, since they usually have loose skin that quickly contracts, and they normally do not get old enough or have contributing diseases such as neuropathy or chronic debilitating illnesses (Mustoe, 2004). Nonetheless, current researchers now understand some of the major factors that lead to chronic wounds, among which are ischemia, reperfusion injury, and bacterial colonization (Mustoe, 2004). Filmed by PETA, Covance primate-testing lab, Vienna, Virginia, 2004-5. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are a major group of living organisms. ...

Ischemia

Ischemia is an important factor in the formation and persistence of wounds, especially when it occurs repetitively (as it usually does) or when combined with a patient’s old age (Mustoe, 2004). Ischemia causes tissue to become inflamed and cells to release factors that attract neutrophils such as interleukins (Clark, 2005), chemokines, leukotrienes, and complement factors (Mustoe, 2004). Neutrophil granulocytes (commonly referred to as neutrophils) are a class of white blood cells and are part of the immune system. ... Interleukins are a group of cytokines that were first seen to be expressed by white blood cells (leukocytes, hence the -leukin) as a means of communication (inter-). The name is sort of a relic though; it has since been found that interleukins are produced by a wide variety of bodily... Chemokines are a class of chemotactic cytokines, or small secreted protein signals. ... Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase. ...

While they fight pathogens, neutrophils also release inflammatory cytokines and enzymes that damage cells (Mustoe, 2004; Snyder, 2005). One of their important jobs is to produce ROS to kill bacteria, for which they use an enzyme called myeloperoxidase (Mustoe, 2004). The enzymes and ROS produced by neutrophils and other leukocytes damage cells and prevent cell proliferation and wound closure by damaging DNA, lipids, proteins (Alleva et al., 2005), the ECM, and cytokines that speed healing (Mustoe, 2004). Neutrophils remain in chronic wounds for longer than they do in acute wounds, and contribute to the fact that chronic wounds have higher levels of inflammatory cytokines and ROS (Schönfelder et al., 2005; Taylor et al., 2005). Since wound fluid from chronic wounds has an excess of proteases and ROS, the fluid itself can inhibit healing by inhibiting cell growth and breaking down growth factors and proteins in the ECM (Snyder, 2005). Cytokines are small protein molecules that regulate communication among immune system cells and between immune cells and those of other tissue types. ... Myeloperoxidase (MPO) is a peroxidase enzyme (EC 1. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid —usually in the form of a double helix— that contains the genetic instructions specifying the biological development of all cellular forms of life, and most viruses. ... Figure 1: Structure of a Lipid. ...

Bacterial colonization

Since more oxygen in the wound environment allows white blood cells to produce ROS to kill bacteria, patients with inadequate tissue oxygenation, for example those who suffered hypothermia during surgery, are at higher risk for infection (Mustoe, 2004). The host’s immune response to the presence of bacteria prolongs inflammation, delays healing, and damages tissue (Mustoe, 2004). Infection can lead not only to chronic wounds but also to gangrene, loss of the infected limb, and death of the patient (Dow, 2001). A request has been made on Wikipedia for this article to be deleted in accordance with the deletion policy. ... It has been suggested that gas gangrene be merged into this article or section. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

Like ischemia, bacterial colonization and infection damage tissue by causing a greater number of neutrophils to enter the wound site (Mustoe, 2004; Snyder, 2005). In patients with chronic wounds, bacteria with resistances to antibiotics may have time to develop (Halcón and Milkus, 2004). In addition, patients that carry drug resistant bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA) have more chronic wounds (Halcón and Milkus, 2004). Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. ... Electron micrograph of MRSA Methicillin-resistant Staphylococcus aureus (MRSA) is a specific strain of the Staphylococcus aureus bacterium that has developed antibiotic resistance to all penicillins, including methicillin and other narrow-spectrum β-lactamase-resistant penicillin antibiotics. ...

Growth factors and proteolytic enzymes

Chronic wounds also differ in makeup from acute wounds in that their levels of proteolytic enzymes such as elastase (Edwards et al., 2004; Schönfelder et al., 2005; Snyder, 2005) and matrix metalloproteinases (MMPs) are higher, while their concentrations of growth factors such as PDGF and KGF are lower (Crovetti et al., 2004; Schönfelder et al., 2005; Snyder, 2005). Proteases (proteinases, peptidases or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. ... Protein Crystal Growth Porcine Elastase In molecular biology, elastase is an enzyme from the class of proteases (or better peptidases) that break down proteins. ... Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases, which are capable of collectively degrading all kinds of extracellular matrix proteins, but also can process a number of bioactive molecules. ... Platelet-derived growth factor (PDGF) is one of the numerous proteins that regulate cell growth and division. ... KGF is the short form of Kolar Gold Fields in Karnataka. ...

Since growth factors (GFs) are imperative in timely wound healing, inadequate GF levels may be an important factor in chronic wound formation (Crovetti et al., 2004). In chronic wounds, the formation and release of growth factors may be prevented, the factors may be sequestered and unable to perform their metabolic roles, or degraded in excess by cellular or bacterial proteases (Crovetti et al., 2004).

Chronic wounds such as diabetic and venous ulcers are also caused by a failure of fibroblasts to produce adequate ECM proteins and by keratinocytes to epithelialize the wound (Foy et al., 2004). Fibroblast gene expression is different in chronic wounds than in acute wounds (Foy et al., 2004). A fibroblast is a cell that makes the structural fibers and ground substance of connective tissue. ... The keratinocyte is the major cell type of the epidermis, making up about 90% of epidermal cells. ...

Though all wounds require a certain level of elastase and proteases for proper healing, too high a concentration is damaging (Edwards et al., 2004). Leukocytes in the wound area release elastase (Edwards et al., 2004; Schönfelder et al., 2005), which increases inflammation, destroys tissue, proteoglycans, and collagen (Kanda and Watanabe, 2005), and damages growth factors, fibronectin, and factors that inhibit proteases (Edwards et al., 2004). The activity of elastase is increased by albumin, which is the most abundant protein found in chronic wounds (Edwards et al., 2004). However, chronic wounds with inadequate albumin are especially unlikely to heal, so regulating the wound's levels of that protein may in the future prove helpful in healing chronic wounds (Edwards et al., 2004). Proteoglycans represent a special class of glycoprotein that are heavily glycosylated. ... Tropocollagen triple helix. ... You may be looking for albumen, or egg white. ...

Excess matrix metalloproteinases, which are released by leukocytes, may also cause wounds to become chronic (Stanley et al., 2005). MMPs break down ECM molecules (Stanley et al., 2005), growth factors, and protease inhibitors, and thus increase degradation while reducing construction, throwing the delicate compromise between production and degradation out of balance (Lai et al., 2004; Schönfelder et al., 2005).

Treatment

Though treatment of the different chronic wound types varies slightly (Gottrup, 2004), appropriate treatment seeks to address the problems at the root of chronic wounds, including ischemia, bacterial load, and imbalance of proteases (Mustoe, 2004). Various methods exist to ameliorate these problems, including antibiotic and antibacterial use, debridement, irrigation, vacuum-assisted closure, warming (Mustoe, 2004), oxygenation, moist wound healing, removing mechanical stress (Moreo, 2005), and adding cells or other materials to secrete or enhance levels of healing factors (Velander et al., 2004).

Preventing and treating infection

To lower the bacterial count in wounds, therapists may use topical antibiotics, which kill bacteria and can also help by keeping the wound environment moist (Patel et al., 2000; Brem et al., 2004), which is important for speeding the healing of chronic wounds (Taylor et al., 2005; Thomas et al., 2005). Some researchers have experimented with the use of tea tree oil, an antibacterial agent which also has anti-inflammatory effects (Halcón and Milkus, 2004). Disinfectants are contraindicated because they damage tissues and delay wound contraction (Patel et al., 2000). Further, they are rendered ineffective by organic matter in wounds like blood and exudate and are thus not useful in open wounds (Patel et al., 2000). An antibiotic is a drug that kills or slows the growth of bacteria. ... Tea tree oil Tea tree oil is an yellowish green-tinged essential oil with a fresh camphoraceous odour. ... Disinfection The destruction of pathogenic and other kinds of microorganisms by physical or chemical means Disinfectants are chemical substances used to kill viruses and microbes (germs), such as bacteria and fungi. ... An exudate is any thick fluid that is actively secreted by cells as a result of disease. ...

A greater amount of exudate and necrotic tissue in a wound increases likelihood of infection by serving as a medium for bacterial growth away from the host’s defenses (Mustoe, 2004). Since bacteria thrive on dead tissue, wounds are often surgically debrided to remove the devitalized tissue (Brem et al., 2004; Mustoe, 2004; Snyder, 2005). Debridement and drainage of wound fluid are an especially important part of the treatment for diabetic ulcers, which may create the need for amputation if infection gets out of control (Gottrup, 2004). Mechanical removal of bacteria and devitalized tissue is also the idea behind wound irrigation, which is accomplished using pulsed lavage (Mustoe, 2004). Necrosis (in Greek Νεκρός = Dead) is the name given to unprogrammed death of cells/living tissue (compare with apoptosis - programmed cell death). ... Debridement is a surgical term referring to the surgical removal of infected or otherwise non-viable tissue to improve the healing potential of the remaining healthy tissue. ... In medicine, lavage is a general term refering to cleaning or rinsing. ...

Negative-pressure wound therapy (NPWT) is a treatment that improves ischemic tissues and removes wound fluid used by bacteria (Mustoe, 2004; Moreo, 2005). This therapy, also known as vacuum-assisted closure, reduces swelling in tissues, which brings more blood and nutrients to the area, as does the negative pressure itself (Moreo, 2005; Mustoe, 2004; Snyder, 2005). The treatment also decompresses tissues and alters the shape of cells, causes them to express different mRNAs and to proliferate and produce ECM molecules (Moreo, 2005; Snyder, 2005). The interaction of mRNA in a eukaryote cell. ...

Super-oxidized water, such as the relatively new non-toxic Microcyn Technology, has shown itself to be highly effective in killing infectious bacteria, virus, spores and fungi in a wound site without damaging the healthy tissue surrounding the wound.

Treating ischemia and hypoxia

Blood vessels constrict in tissue that becomes cold and dilate in warm tissue, altering blood flow to the area. Thus keeping the tissues warm is probably necessary to fight both infection and ischemia (Thomas et al., 2005). Some healthcare professionals use ‘radiant bandages’ to keep the area warm, and care must be taken during surgery to prevent hypothermia, which increases rates of post-surgical infection (Mustoe, 2004). Hypothermia is a medical condition in which the victims core body temperature has dropped to significantly below normal and normal metabolism begins to be impaired. ...

Underlying ischemia may also be treated surgically by arterial revascularization, for example in diabetic ulcers, and patients with venous ulcers may undergo surgery to correct vein dysfunction (Gottrup, 2004). Revascularization is the process of restoring the functionality of an affected organ. ...

Diabetics that are not candidates for surgery (and others) may also have their tissue oxygenation increased by Hyperbaric Oxygen Therapy, or HBOT, which can compensate for limitations of blood supply and correct hypoxia (Gottrup, 2004; Alleva et al., 2005; Snyder, 2005). In addition to killing bacteria, higher oxygen content in tissues speeds growth factor production, fibroblast growth, and angiogenesis and (Alleva et al., 2005; Snyder, 2005). Unfortunately, increased oxygen levels also means increased production of ROS (Alleva et al., 2005). Antioxidants, molecules that can lose an electron to free radicals without themselves becoming radicals, can lower levels of oxidants in the body and have been used with some success in wound healing (Schönfelder et al., 2005). Hyperbaric oxygen therapy (HBOT) is the medical use of oxygen at a higher than atmospheric pressure. ... Hypoxia is a pathological condition in which the body as a whole (generalized hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. ... Angiogenesis is the physiological process involving the growth of new blood vessels from pre-existing vessels. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

Growth factors and hormones

Since chronic wounds underexpress growth factors necessary for healing tissue, chronic wound healing may be speeded by replacing or stimulating those factors (Crovetti et al., 2004) and by preventing the excessive formation of proteases like elastase that break them down (Edwards et al., 2004; Schönfelder et al., 2005).

One way to increase growth factor concentrations in wounds is to apply the growth factors directly, though this takes many repetitions and requires large amounts of the factors (Schönfelder et al., 2005). Another way is to spread onto the wound a gel of the patient’s own blood platelets, which then secrete growth factors such as vascular endothelial growth factor (VEGF), insulin-like growth factor 1–2 (IGF), PDGF, transforming growth factor-β (TGF-β), and epidermal growth factor (EGF) (Crovetti et al., 2004; Yaple, 2005). Other treatments include implanting cultured keratinocytes into the wound to reepithelialize it (Brem et al., 2004; Velander et al., 2004) and culturing and implanting fibroblasts into wounds (Brem et al., 2004). Some patients are treated with artificial skin substitutes (Brem et al., 2004; Supp and Boyce, 2005) that have fibroblasts and keratinocytes in a matrix of collagen to replicate skin and release growth factors (Ehrlich, 2004). A 250 ml bag of newly collected platelets. ... Vascular endothelial growth factor or VEGF is an important signal protein involved in angiogenesis. ... The insulin-like growth factors (IGFs) are polypeptides with high sequence similarity to insulin. ... Transforming growth factor (TGF) is one of many characterized growth factors that exist in nature. ... Epidermal Growth Factor or EGF is a 6045 Da protein with 53 amino acid residues and three intramolecular disulfide bonds. ...

In other cases, skin from cadavers is grafted onto wounds (Supp and Boyce, 2005), providing a cover to keep out bacteria and preventing the buildup of too much granulation tissue, which can lead to excessive scarring (Ehrlich, 2004). Though the allograft (skin transplanted from a member of the same species) is replaced by granulation tissue and is not actually incorporated into the healing wound, it encourages cellular proliferation and provides a structure for epithelial cells to crawl across (Snyder, 2005). On the most difficult chronic wounds, allografts may not work, requiring skin grafts from elsewhere on the patient, which can cause pain and further stress on the patient’s system (Taylor et al., 2005). Cadaver is a euphemism for a corpse or body. ... Skin Graft is an influential contemporary no wave, noise rock, art punk, rock label based in Chicago. ... Granulation tissue is the tissue that replaces a fibrin clot in healing tissue. ... This article or section is in need of attention from an expert on the subject. ... An allograft is a transplanted organ or tissue from a genetically non-identical member of the same species. ... In biology, a species is the basic unit of biodiversity. ... In zootomy, epithelium is a tissue composed of a layer of cells. ...

Collagen dressings are another way to provide the matrix for cellular proliferation and migration, while also keeping the wound moist and absorbing exudate (Schönfelder et al., 2005).

Since levels of protease inhibitors are lowered in chronic wounds, some researchers are seeking ways to heal tissues by replacing these inhibitors in them (Lai et al., 2004). Secretory leukocyte protease inhibitor (SLPI), which inhibits not only proteases but also inflammation and microorganisms like viruses, bacteria, and fungi, may prove to be an effective treatment (Lai et al., 2004). Protease inhibitor can refer to: Protease inhibitor (pharmacology): a class of medication that inhibits viral protease Protease inhibitor (biology): a group of proteins that inhibit proteases. ... The human immunodeficiency virus (HIV) A bacteriophage virus A virus is a submicroscopic parasitic particle that infects cells in biological organisms. ... Divisions Chytridiomycota Deuteromycota Zygomycota Glomeromycota Ascomycota Basidiomycota Fungus growing on a tree in Borneo A fungus (plural fungi) is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells. ...

Research into hormones and wound healing has shown estrogen to speed wound healing in elderly humans and in animals that have had their ovaries removed, possibly by preventing excess neutrophils from entering the wound and releasing elastase (Kanda and Watanabe, 2005). Thus the use of estrogen is a future possibility for treating chronic wounds. A hormone (from Greek horman - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... Estrogens (also oestrogens) are a group of steroid compounds, named for their importance in the oestrus cycle, functioning as the primary female sex hormone. ... Human female internal reproductive anatomy Ovaries are egg-producing reproductive organs found in female organisms. ...

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