Question

Describe the local and systemic factors that influence wound healing, stating whether each of these influences, accelerates or retard the rate of healing.  

Answer 1

Wound healing

phases:

.hemostasis

.inflammation

.proliferation and

.remodeling

Factors affecting wound healing

. Local factors

. Systemic factors

1) Local Factors

.Oxygenation (accelerates wound healing)

It prevents wounds from infection, induces angiogenesis, increases keratinocyte differentiation, migration, and re-epithelialization, enhances fibroblast proliferation and collagen synthesis, and promotes wound contraction.

Oxygen is important for cell metabolism, especially energy production by means of ATP, and is critical for nearly all wound-healing processes.

.Infections

Inflammation is a normal part of the wound-healing process, and is important to the removal of contaminating micro-organisms.

2) Systemic Factors :

.Age

increased age is a major risk factor for impaired wound healing.

Delayed wound healing in the aged is associated with an altered inflammatory response, such as delayed T-cell infiltration into the wound area with alterations in chemokine production and reduced macrophage phagocytic capacity .

.Medications

Many medications, such as those which interfere with clot formation or platelet function, or inflammatory responses and cell proliferation have the capacity to affect wound healing.

Medications such as;

glucocorticoid steroids

non-steroidal anti-inflammatory drugs and

chemotherapeutic drugs

.Obesity

Obese individuals frequently face wound complications, including skin wound infection, dehiscence, hematoma and seroma formation, pressure ulcers, and venous ulcers.

.Nutrition

Most obvious is that malnutrition or specific nutrient deficiencies can have a profound impact on wound healing after trauma and surgery.

.Carbohydrates, Protein, and Amino Acids

Glucose is the major source of fuel used to create the cellular ATP that provides energy for angiogenesis and deposition of the new tissues

Protein is one of the most important nutrient factors affecting wound healing.

A deficiency of protein can impair capillary formation, fibroblast proliferation, proteoglycan synthesis, collagen synthesis, and wound remodeling.

sufficient arginine(amino Acid) levels are needed to support collagen deposition, angiogenesis, and wound contraction.

.Vitamins, Micronutrients, and Trace Elements  

These are essential factors of wound healing.

.Fatty Acids

Lipids are used as nutritional support for surgical or critically ill patients to help meet energy demands and provide essential building blocks for wound healing and tissue repair.

.Alcohol Consumption

Clinical evidence and animal experiments have shown that exposure to alcohol impairs wound healing and increases the incidence of infection

.Smoking

patients who smoke show a delay in wound healing and an increase in a variety of complications

.Diabetes

the impaired healing that occurs in individuals with diabetes involves hypoxia, dysfunction in fibroblasts and epidermal cells, impaired angiogenesis and neovascularization, high levels of metalloproteases, damage from ROS and AGEs, decreased host immune resistance, and neuropathy.

.Stress

Studies in both humans and animals have demonstrated that psychological stress causes a substantial delay in wound healing.

Stress up-regulates glucocorticoids (GCs) and reduces the levels of the pro-inflammatory cytokines IL-1β, IL-6, and TNF-α at the wound site. Stress also reduces the expression of IL-1α and IL-8 at wound sites—both chemoattractants that are necessary for the initial inflammatory phase of wound healing.

.Sex Hormones in Aged Individuals

Sex hormones play a role in age-related wound-healing deficits. Compared with aged females, aged males have been shown to have delayed healing of acute wounds. A partial explanation for this is that the female estrogens (estrone and 17β-estradiol), male androgens (testosterone and 5α-dihydrotestosterone, DHT), and their steroid precursor dehydroepiandrosterone (DHEA) appear to have significant effects on the wound-healing process