BB&T Contributing Writer
TAMPA — More than 2,000 attendees at the joint annual meeting of the Symposium on Advanced Wound Care (SAWC) and the Wound Healing Society (WHS; Maitland, Florida) were shown a proliferation of dressings and device used to treat a wide spectrum of wounds. These technologies ad-dress not on the variety of wounds but the increasing, and unfortunate, opportunities: aging demographics worldwide, increasing numbers
Inhibitors of matrix metalloproteinase
A key problem in wound healing is to limit matrix metalloproteinase (MMP) production which causes a chemical reaction that prouces inflammation and accelerates collagen degradation.
Dermagenics, a subsidiary of Greystone Medical (Fort Meyers, Florida), featured EpiMax, an active wound dressing impregnated with polyhydrated ionogen (PHI) ointment that inhibits MMPs. EpiMax normalizes the wound micro-environment by reducing excessive inflammation and thereby facilitating re-epithelialization of the wound. 3M Health Care (Longborough, UK) will sell it in the UK brand-named Tegaderm Matrix. PHI, Dermagenics core technology, contains a blend of trace metal ions that also occur in serum and wound exudates.
An investigation of the effect of PHI on patterns of gene expression in cultures of normal and diabetic human dermal fibroblasts and its impact on recalcitrant diabetic and neuropathic ulcers was reviewed in a poster presented by Gregory Schultz, PhD, a leading researcher on MMPs at the University of Florida (Gainesville, Florida).
Quick-Med Technologies (Gainesville, Florida) is developing the Nimbus family of advanced antimicrobial quaternary ammonium-based polymers that destroy bacteria at the cellular level, thereby eliminating the risk of developing drug resistance. The Nimbus technology works by creating a permanent bond with a multitude of substrates and is an effective alternative to silver-based antimicrobial dressings as a fraction of the cost. A poster was presented on the results of in vitro testing which demonstrated highly effective microbicidal activity against pathogenic bacteria, viruses and fungi, and the suppression of odor from bacterial metabolism in dressings.
Another of the company’s posters provided data on Nimbuderm, a skin sanitizer with sustained microbicidal activity that persists for six hours in laboratory testing, even after repeated rinsing with water.
Quick-Med is conducting research on MultiStat technology for inhibiting MMP production. It has a government grant to investigate the use of Ilomastat, an MMP inhibitor, for the development of a specialized dressing to be used on wounds caused by exposure to mustard gas, a blistering agent that has been characterized as a primary threat by defense analysts.
Quick-Med has licensed its Nimbus antimicrobial technology to Derma Sciences (Princeton) for use in specific wound care products, including gauze sponges, bandage rolls, packing strips, and in Unna Boot compression dressings. Studies have shown that it maintains its properties even in the presence of blood.
Rimon Therapeutics (Toronto) is researching applications for Theramers, a family of medical polymers that have biological activity and can potentially be used in scaffolds, beads and coatings. Theramers work on contact by disrupting the bacterial cell membrane and inhibiting the activity of MMPs.
The company gave an oral presentation of a 32-subject clinical trial on MI-Sorb, a Theramer-based dressing, used on ulcerated wounds which validated its efficacy.
Other applications of its core technology are Angiogenic Theramer for inducing the growth of new blood vessels in wounds or other ischemic tissue; AM Theramer, a thermoplastic material that kills gram positive and gram negative bacteria without harming mammalian cells; and ThermaGel, a polymer that changes from a liquid to a strong gel at body temperature.
Preparing the wound environment
Optimal preparation and cleaning of the wound environment is critical for the best chance of healing.
Soluble Systems (Hampton, Virginia) later this year plans to launch Theragauze, a non-stick, moist wound dressing comprising a polyester non-woven fabric imbedded with a cross-linked matrix of microscopic polymeric vacuoles that exhibit oppositional tension for balanced moisture control. It has been described in a report by Dr. Adam Landsman, assistant professor of surgery at Harvard Medical School (Cambridge, Massachusetts) as a “smart” wound dressing able to either dispense or extract moisture from a wound and simultaneously control moisture differentially at adjacent sites, even within the same wound bed.
Hollister (Libertyville, Illinois) introduced its Triact wound care technology that utilizes a patented composition of hydrocolloid particles impregnated with a petrolatum-based formulation on a non-occlusive fine polyester mesh facing, through which the wound exudate passes to form a optimal wound healing environment.
The company also introduced an indwelling bowel catheter for medication delivery and control of fecal drainage.
3M Health Care (St. Paul, Minnesota) introduced its Tegaderm absorbent clear acrylic dressing, claiming that it can absorb as much as hydrocolloid dressings and can stay on the wound site for seven to 10 days. Its transparency allows for monitoring a wound without having to make a dressing change. It is intended for use on pressure ulcers, donor sites, abrasions and skin tears.
Smith & Nephew Wound Management (Largo, Florida), a subsidiary of Smith & Nephew (S&N; Hull, UK), was promoting its Allevyn multi-layer dressings for their breathability and fluid-handling capacity. A porous facing is backed with an absorbent foam and a top film that becomes more breathable by adjusting the vapor transmission rate as exudate levels increase, thereby maintaining an optimal moisture balance. Allevyn dressings are sold in various shapes and sizes for use on common wound types, high-exudate wounds, wounds in the sacral area and for use around tracheostomy and other tubes. The company also featured its antimicrobial Iodosorb gel and Iodoflex pad for use on ulcerated wounds.
S&N recently reacquired marketing rights to these products from Healthpoint (Fort Worth, Texas). They contain 0.9% Cadexomer and release iodine for up to 72 hours.
S&N also recently reported a worldwide sales and distribution agreement with Covalon Technologies (Mississauga, Canada) for its ColActive advanced dressings for wounds and surgical applications. Included in the agreement is Covalon’s surface coating technology for use in time-release drug delivery on medical devices for treating problems of infection, poor biocompatibility and microbial attachment.
ColActive dressings can be used to treat a range of wound types, including pressure ulcers, diabetic foot ulcers and venous leg ulcers.
The products contain collagen and sodium alginate which create a moist wound environment, allowing for more efficient functioning of fibroblasts and macrophages. A poster was presented on ColActive Ag, an absorbent collagen dressing with silver that exhibited broad spectrum microbial growth inhibition.
Ferris Manufacturing (Burr Ridge, Illinois) featured its Shapes by PolyMem, pre-cut dressings made from QuadraFoam, a material that contains a cleansing agent activated by moisture, then gradually released into the wound bed. PolyMem dressings can cleanse, fill, absorb and moisten wounds throughout the healing process.
Creams, gels, powders
Wound dressings are augmented by a variety of modalities, such as creams, gels and powders.
Bioderm Sciences (Oxford, Mississippi) has licensed marketing rights from Nawa Heilmittel (Nuremburg, Germany) for formulated wound care products including an acidic cream and solution that contain zinc and iron providing an aseptic moist wound environment conducive to the body’s natural healing. It also markets a multi-layered, absorbent wound dressing that has a reservoir for its wound solution and can be left on the post-surgical wound site four to five days.
Swiss-American Products (Carrollton, Texas), a contract manufacturer of skin care products, is seeking FDA 510(k) clearance for its Elta Silver-Gel, a broad spectrum ionic-silver gel which it plans to launch this year.
The gel makes full contact with the wound bed so as to have greater antimicrobial effectiveness than the many silver-containing antimicrobial dressings widely displayed by exhibitors.
It will compete against the SilvaSorb gel from Medline Industries (Mundelein, Illinois) and Silver Shield skin and wound gel introduced six months ago by Anacapa Technologies (San Dimas, California).
Swiss-American supplies a wound cleanser for use prior to application of the gel which is then covered with a dressing to keep the wound moist. It also sells the Elta Hydrovase, an enzyme-containing hydrogel and THINSite, a conformable, multi-layered wound dressing.
Biosyntech (Laval, Quebec, Canada) is developing BST-DermOn, a topical gel therapy for treating pressure, diabetic and venous ulcers. It is based on chitosan which possesses hemostatic and bacteriostatic properties, conforms to a wound and stimulates the natural healing process. It maintains a wound’s moist environment while allowing gas exchange. BST-DermOn is in a pivotal trial in Canada. The company is targeting for market approval in Canada and Europe in 2009, to be followed soon thereafter in the U.S.
Biolife (Sarasota, Florida) featured its patented Pro QR Quick Relief, a hydrophilic powder (polystyrene divinyl benzene) that contains a potassium/iron oxyacid salt that forms a protective matrix upon contact with blood but does not enter the bloodstream. It is used professionally on peristomal ulcers, for bleeding around catheter lines and on skin tears. It is also sold at retail for stopping nosebleeds and to stop bleeding from minor wounds.
Biological dressings and scaffolds
Promethean LifeSciences (Pittsburgh) featured its product GammaGraft, an irradiated human skin allograft that can be stored for two years at room temperature for use as a temporary cover of partial thickness wounds, including chronic wounds, burns and traumatic injuries. GammaGraft does not adhere to necrotic tissue or to an infected wound site.
Integra LifeSciences (Plainsboro, New Jersey) markets its Matrix Wound Dressing, a porous and biodegradable matrix of cross-linked bovine tendon collagen and glycosaminoglycan. It provides a scaffold for cellular invasion and capillary growth. Applications include pressure, venous and diabetic ulcers, full thickness wounds, second degree burns, trauma and surgical wounds (i.e., donor sites/grafts, podiatric and post-laser surgery).
Similar products include the Promogran Matrix wound dressing from Johnson & Johnson Wound Management, a unit of Ethicon (Somerville, New Jersey), that combines collagen with oxidized regenerated cellulose; Puracol Plus, a collagen microscaffold wound dressing from Medline Industries (Mundelein, Illinois); and Graftjacket Matrix, a processed human dermal membrane for ulcer repair which includes multiple collagen types, elastin and proteoglycans from Wright Medical Technology (Arlington, Tennessee)
Cell-based bioengineered wound dressings for diabetic and venous leg ulcers are Dermagraft from Advanced BioHealing (La Jolla, California) and Apligraf from Organogenesis (Canton, Massachusetts).
Pegasus Biologics (Irvine, California) produces bioimplants for use in soft tissue reinforcement in orthopedics, sports medicine, neurosurgical and spine applications.
It also was exhibiting Unite Biomatrix, an enzyme-resistant, fenestrated Type 1 collagen scaffold that conforms to the wound bed and allows for suture retention.
Unite Biomatrix is stabilized by a proprietary process that makes it resistant to premature enzyme degradation. It is covered with a secondary non-adhesive dressing used on diabetic foot ulcers. Unite Biomatrix is prepared from equine pericardium that is decellularized and crosslinked. The company also markets OrthADAPT, a tissue scaffold that can be used to repair and reinforce soft tissues such as tendons and ligaments.
Argentum Medical (Willowbrook, Illinois) markets Biopad, a primary wound dressing that is also composed of equine Type 1 collagen. The product has been marketed in Europe for many years and was introduced into the U.S. about one year ago. It is used to control minor bleeding and for the management of ulcerated wounds.
Devices used in wound care
Wound Care Technologies (Eden Prairie, Minnesota) displayed its DermaClose RC, continuous external tissue expander for the closure of moderate to large wounds. DermaClose allows for the tension to be set without further adjustment. Skin anchors are placed about 1.5 cm from the edge of the wound and stapled in place. The tension line is attached around each skin anchor and tightened under an audible signal is received indicating full tension. Because transparent, the device permits viewing of the wound bed.
Medela (Baar, Switzerland/McHenry, Illinois), the leading producer of breast pumps, is a new entrant in the negative pressure wound therapy market, following the commercial success of Kinetic Concept’s (KCI; San Antonio) V.A.C. devices and the entry of BlueSky Medical Group (Carlsbad, California). Medela used its suctioning technology to develop its recently launched Invia negative pressure wound therapy system.
It comprises the Vario aspirator pump which applies a gentle negative pressure to the wound and a dressing kit that controls infection and promotes healing. It is designed to maintain the integrity of the wound environment and aid in the healing of chronic and acute wounds, diabetic and neuropathic ulcers, pressure ulcers, partial thickness burns and dehisced wounds. The Invia Healing System will first be available for the acute care market, followed by extended care, long term care and home care.
There has been ongoing litigation among the suppliers of negative pressure wound therapy products. Appeals were recently filed by KCI and Medela with the U.S. District Court for the Western District of Texas in patent infringement litigation that KCI brought against Medela and BlueSky Medical Group. The patents at issue were licensed by KCI from Wake Forest University (Winston-Salem, North Carolina) relating to the V.A.C. technology used to treat serious, complex wounds.
On the closing day of the symposium, KCI reported on the acute phase results of a randomized and controlled clinical trial on the use of its V.A.C. therapy in the treatment of complex diabetic foot ulcers. V.A.C. therapy resulted in a significant increase in the number of wounds that were completely closed and a significant improvements in the formation of granulation tissue and the time to achieve wound closure.
AION Diagnostics reports preliminary study results
In more news involving Western Australia, nano-diagnostics company AION Diagnostics (Perth), a developer of imaging agents, reported positive preliminary results of a pilot study showing the high intravascular contrast enhancement of modified porous silicon (mpSi) in reduced dose amounts.
In the in vivo study, a bolus injection of mpSi in saline suspension was administered intravenously. Ultrasonographic imaging of the vasculature and heart indicated that the mpSi showed high echogenicity and produced strong contrast enhancement with no change in vital signs or evidence of acute cardiovascular or respiratory adverse effects. Silicic acid is a natural byproduct of silicon and mpSi metabolism.
The trialed intravascular contrast agent is based on the same formulation as AION’s Marking Agent, a medical device to be registered under the CE mark and the FDA 510(K) route.
The interim results provide “an excellent advancement to consolidate AION’s position in the ultrasound imaging sector,” the company said, calling ultrasound “a powerful imaging technique that can be used in a wide variety of settings, including surgical, outpatient, emergency room and community healthcare environments.”
mpSi also is visible under other key imaging modalities, including MRI, CT, X-ray and optical imaging.
The European contrast media market, inclusive of all imaging modalities, generated revenues of EUR 1.02 billion in 2006 with an expected CAGR of 7.2% for 2006-2013.
AION said current ultrasound contrast agents have a short imaging life due to their inherent fragility and rapid removal from the bloodstream. The physical stability of mpSi particles overcomes this issue, it said, offering advantages with increased length of time available to clinicians in performing examinations.
“The stability of mpSi particles also will allow clinicians to use higher resolution imaging than is possible with conventional contrast media because of their fragility, which translates to better contrast and improved visualization of anatomical detail,” the company said. It noted that the high visibility of mpSi at low dose is of “vital importance in molecular imaging applications due to the necessity to image minute clusters of diseased cells.”