Short NotesInflammation What is it? Inflammation is a non-specific and immediate protective process that the body undergoes in response to various injurious or noxious stimuli. Such stimuli may include the introduction of a foreign body, such as a micro-organism, or it may result from physical trauma. The Signs calor (heat), rubor (redness), tumor (swelling), dolor (pain), functio laesa (loss of function) These signs may manifest when inflammation exists in or just under the skin. Classification Inflammation may be classified by duration. Inflammation can be Acute, Subacute or Chronic. Acute Inflammation = minutes to days Subacute Inflammation = 2 to 6 weeks Chronic Inflammation = months to years The Acute Inflammatory Response is an important part of Wound Healing. Wound Healing Wound healing involves the inflammatory process such that normal tissue can be restored following injurious or noxious stimuli. The process of wound healing may include 3 parts: -Inflammatory Phase -End of Inflammation -Tissue Formation Inflammatory Phase: Vascular response Cell-signalling Release + Activation of Mediators Vascular response Vasodilation: incr. vascular permeability + recruitment of blood cells to site Clotting: Thrombin acts on fibrinogen à fibrin à fibrin clots Platelet activation: Coagulation Factor V111 necessary for platelet Adhesion + plug formation Platelets adhere via integrins to injured site Thrombin promotes: platelet aggregation + granule release --> generates inflammatory response Cell signalling -Damaged endothelial cells release chemical signals to immune cells -Immune cells (e.g. Neutrophil + macrophage +T-cells) recruited to attach to damaged endothelium -Neutrophils +macrophage accumulate to clear inflamed tissue Release + Activation of Mediators Plasma or cell-derived Mediator groups: Toll-like Receptors (TLRs) [CD 14] Arachidonic Acid (AA) mediators [ PGD2 | thromboxane | PGE2 | prostacyclin |LTs] Mast cells [ Histamine | TNF | kinin | LTs] Complements [C3a | C5A] Hageman factor [kinin: bradykinin] Other Mediators Cytokines [IL6 | TNF-alpha] Chemokines Acute Phase Reactive Proteins [protease inhibitors | coagulation proteins |complement proteins | transport proteins |C-reactive protein] End of Inflammation Specific signals sent to site to prevent further entry of neutrophil + T-cells. Lipoxins: -Generated by neutrophil + macrophage -Metabolite of arachidonic acid pathway -Arachidonic Acid = omega 6 PUFA -Arachidonic Acid: generates both pro-inflammatory and pro- resolving lipid mediators Resolvins + Protectins: - EPA/DHA = omega 3 PUFA -EPA/DHA: anti-inflammatory, pro-resolving and cytoprotective lipid mediators Note: omega 3 + 6 PUFA are important in this response. Tissue Formation -Keratinocytes: goes to wound to form protective cover -Fibrocytes: fill in underlying dermis between strands of newly formed supporting collagen -Capillary Vessels: supply regenerating tissue with oxygen + nutrients Injured site may gain 20% of ultimate strength by 3 weeks. A maximum of 70% of ultimate strength can be regained thereafter. Nutritional support involved in Acute Inflammation and Wound Healing We can recapitulate here what we potentially need in order for the body to work through the phases of wound healing. We can do this in a step-wise fashion. Let us go over the main steps of wound healing: -Inflammatory Phase -End of Inflammation -Tissue Formation In the inflammatory step, we have come across the need for clotting, as we have seen fibrin clots being formed at this stage and that platelets work to adhere to the damaged endothelium or lining. From this perspective, we can see that clotting is necessary in order to diminish further blood losses from the body. Not only does this action limit further blood loss, but it allows the necessary cells needed to clear the inflammation to arrive and accumulate in a timely fashion. From a nutritional perspective, Vitamin K is a vital component that helps support the processes needed for clotting to take place in the body. In fact, Vitamin K is essential for the production of four distinct clotting factors: prothrombin, factors VII, IX and X. Additionally, Vitamin D works in this step as it exerts immunomodulatory effects on both the innate and adaptive immune system, more so as it relates to an infective process that may be occurring in the body. Vitamin A is also a very crucial vitamin working in this step as it plays regulatory roles in cellular immune responses and humoral immune processes. At the end of inflammation, we have met the need for the Poly Unsaturated Fatty Acids omega 3 and omega 6. They were both necessary for the appropriate cell-signalling that would prevent further inflammatory cells to enter site and thereby helps to break or bring to a close the acute inflammatory phase so that tissue regeneration can commence. When we look at the final part, we have now tissue rebuilding. In order for tissues to be properly rebuilt with strong integrity, we need Vitamin C and E, which are powerful anti-oxidants, that support collagen formation and prevent excess scar tissue formation. So, these vitamins help with restoring the lining of damaged site and prevent further insults or injuries by blocking or buffering any potential for free radicals to damage site. Vitamin A is also necessary in this part as it is heavily involved in repair of DNA and tissue. Vitamin B1 also has a function in increasing strength of tissue as it reforms. Zinc also as role in immune function, collagen synthesis and fibrocyte migration. What is also important to note is the protein that is required for the manufacture of all the cells and cell fragments necessary that participate in these processes. Further, adequate energy (in the form of fat) and oxygen are needed to provide that supportive environment to allow these processes to exist. These are just a few of the nutrients identified that may help in the stage of acute inflammation. But it does help to raise greater awareness to help us identify sources of food that can help in the process of wound healing. For now, we can review rich sources of the Vitamins, Minerals and Fatty Acids: Vitamin A Liver and liver products (avoid in pregnancy) Fish oils Eggs Sources of beta carotene: carrots | red peppers | spinach | broccoli | tomatoes Vitamin D Oily fish (salmon, mackerel etc.) |milk | margarine | breakfast cereals | eggs | liver Vitamin E Almonds | sunflower seeds and oil | hazelnuts | peanuts and peanut butter Vitamin K Green leafy vegetables (spinach, broccoli, cabbage, kale etc.) | soya bean oil | eggs | meat | dairy products Vitamin C Citrus fruits (oranges, lemons, cherries etc.) | guava | mango | papaya |pepper | brussel sprouts | broccoli | sweet potato Vitamin B1 (thiamine) Salmon | flax seeds | sunflower seeds | black-eyed peas | lentils | green peas | oatmeal | quinoa Omega 3 Olive oil |Salmon | tuna | sardines | mackerel | whitefish | herring Omega 6 Walnuts | pecans | pistachios | sunflower seeds | soy bean oil | corn oil | peanut butter Zinc Lamb | leafy and root vegetables | crabs and shellfish | beef | whole grains | eggs | nuts A Note on The Food Matrix The food matrix defines the natural structure and order of the component parts that make up the whole food. Having an understanding of how things are arranged and organized within the substance of the food itself can we really appreciate how functional the process by which we consume our food. When we respect the whole food, we also respect that interaction and interface between the food and the body. The body understands the food, as we eat or drink. So, the body will also understand how to break down what, what to take in through absorption and what to leave out as refuse. We therefore can trust that when we eat food as part of a meal, in its more natural state, we are actually receiving the vitamins, minerals and other nutrients that we need in adequate amounts, provided that our bodies are physiologically optimal to achieve such states. Essentially, consuming whole foods may help in the process through which we adequately receive those nutrients that are essential for wound healing. References
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