Hyaluronic Acid

Abstract

Hyaluronic acid (HA) is a non-sulphated glycosaminoglycan. It is a natural polymer characterised by a coiled linear chain in particularly well-hydrated configuration composed of repeating disaccaride units. In mammals, its molecular weight can be extremely wide, ranging from 20 to 4,000 kDa. High molecular mass forms are provided with anti-inflammatory properties. A unique characteristic of HA is hydration (up to 6,000 molecules water/molecule of HA) with a major role in the regulation of fluid balance in the interstitium, a fundamental activity on the amorphous colloidal matrix gluing connective cell and fibers, and many other biological functions including lubrication, solute transport and microcirculatory exchange. HA has been widely used in the treatment of eye, ear, joint and skin disorders; in the last 15 years HA has been also proposed successfully in the treatment of a number of lung diseases in vitro, experimental animals and humans. In particular, inhaled HA at relatively high molecular weight has been proven to prevent bronchoconstiction induced in asthmatics by direct and indirect challenges such as inhalation of methacholine, inhalation of ultrasonically nebulised distilled water, muscular exercise. More recently, in patients affected by chronic obstructive pulmonary diseases, we have demonstrated that repeated administrations of inhaled HA (daily, for 8 weeks) induce significant increase in bronchial patency as well as progressive lung deflation with decrease of residual volume. In conclusion there are elements that can let us state that is perhaps time to change the focus to connective tissue and extracellular matrix substances such as HA, in order to prevent and treat chronic lung diseases.

High molecular weight hyaluronan ameliorates allergic inflammation and airway hyperresponsiveness in the mouse

“…HA is normally a large [molecular weight (MW) Ͼ 10 6 ] polysaccharide, comprised of N-acetyl-glucosamine-glucuronic acid disaccharides repeated up to 10,000 times (69). HA is the most abundant ECM glycosaminoglycan in the human body and is usually found in the peribronchial and perivascular space in the lungs (5). During lung injury, shorter fragments of HA (sHA) (MW, 100,000 -400,000) are either produced de novo or released via enzymatic and nonenzymatic degradation of structural HA (6,23,43,48,61,64,69) and promote inflammation and airway hyperresponsiveness (AHR) (23).…”

Hyaluronic Acid: Perspectives in Upper Aero-Digestive Tract. A Systematic Review

“…), it is also employed for the treatment of arthritis [ 7 ] and a lot of studies on the effect of SH in the lung disease are available in literature, as well [ 10 ]. Formulations of SH have been developed for topical administration as coadjutant treatment in clinical cases of acute and chronic pathologies in the upper aero digestive tract (UADT) and in the tissue healing after UADT surgery, based on the large evidence of data available on SH role in UADT, in animals models [ 11 , 12 ]…”

Effect of Hyaluronic Acid on the Differentiation of Mesenchymal Stem Cells into Mature Type II Pneumocytes

“…hUCMSCs cells were used at early passages (1)(2)(3)(4)(5)(6). The cells were grown in a T-75 cell culture flask (Falcon, Italy), in complete culture medium DMEM, supplemented with 10% FBS and antibiotics (penicillin G sodium 100 U/mL, streptomycin 100 U/mL), in a humidified and controlled atmosphere at 37 • C and 5% CO 2 .…”

“…It was determined that the exogenous HA administered by aerosol or tracheal instillation acts against inflammation, protecting the airways against the hyper-reactivity and remodelling of the bronchial and lung parenchyma [ 4 ]. For example, in patients affected by chronic lung disorders, repeated administrations of inhaled HA, daily, for eight weeks, induced significant increase in bronchial patency as well as progressive lung deflation with decrease of residual volume [ 5 ]. From this perspective, the HA molecule was considered worthy of further exploration for its possible therapeutic role in a variety of respiratory diseases [ 6 ].…”