A novel treatment for venous leg ulcers

Skin perfusion responses under normal and combined loadings: Comparisons between legs with venous stasis ulcers and healthy legs

BACKGROUND

Venous ulcers, also known as stasis ulcers, are skin wounds often found at the medial surface of the lower leg. These wounds are related to chronic venous insufficiencies and affect almost 2.5 million patients every year in the United States.

METHOD

Eighteen participants with venous stasis ulcers on at least one leg and twenty healthy participants were tested. Normal and combined normal and shear loadings were applied to each lower leg and local blood perfusion was monitored. Basal perfusion, post-occlusive reactive hyperemia as well as changes in perfusion due to different loadings were compared.

FINDINGS

Legs with existing venous stasis ulcers ("wounded legs") had the highest reactive hyperemia and basal perfusion values. Legs without ulcers but from participants with venous stasis ulcers ("non-wounded legs") had intermediate reactive hyperemia, and healthy legs exhibited the lowest values. Wounded legs also exhibited the largest decrease in blood perfusion under both normal and combined loadings. Non-wounded legs decreased perfusion similarly to healthy legs under normal loadings; however, non-wounded legs exhibited larger decreases in blood flow than healthy legs in response to shear and normal loading together.

INTERPRETATION

These results suggest that patients with venous stasis disease have abnormal responses to tissue loading and raise the possibility that this technique may have the potential to identify patients at risk for developing a venous stasis ulcer. Moreover, they emphasize the importance of studying shear loading in addition to normal loading in attempting to understand the pathophysiology of this disease.

Regulation of cell-based therapeutic products intended for human applications in the EU

AIMS

Recent developments in the field of cell-based therapeutic products (CBTPs) have forced the EU to revise its legislation on therapeutic products by enacting several new legal instruments. In this study, we investigate how CBTPs are regulated and what determines their regulatory classification. Furthermore, we compare the regulatory burden between CBTPs in different product categories.

MATERIALS & METHODS

Product categories covering CBTPs were identified and characteristics critical for the regulatory classification of a CBTP were determined in each category. The effect of the critical characteristics on the classification was evaluated by constructing a decision tree that covers all possible combinations of the critical characteristics. Differences in the regulatory burden between CBTPs were evaluated by comparing regulations crucial for placing a therapeutic product on the EU market between the product categories.

RESULTS

Regulation of CBTPs has been divided between the main product categories of the EU legal framework for therapeutic products on the basis of the characteristics of the cells that the CBTPs contain. The regulatory burden is lowest for CBTPs regulated as blood, cells or tissues, and highest for CBTPs regulated as medicinal products.

CONCLUSION

CBTPs exist in all product categories of the EU legal framework for therapeutic products. However, the current framework does not cover all possible CBTPs. Furthermore, our results indicate that the regulatory burden of a CBTP is related to the risk it may pose to the health and safety of recipients.

Integration and persistence of an investigational human living skin equivalent (ICX-SKN) in human surgical wounds

AIM

To present the first human clinical data on an investigational living skin graft replacement that is being designed for application where tissue has been lost through surgery, disease or trauma.

MATERIALS & METHODS

The ICX-SKN skin graft replacement is composed of an autosynthesized human collagen-based extracellular matrix and human dermal fibroblasts. In a first study to examine integration and persistence, full-thickness excisional wounds were made in six healthy human female volunteers and the ICX-SKN skin graft replacement applied and dressed. The surgical wounds were examined for up to 28 days post-application and the graft excised from each volunteer.

RESULTS

Pre-excision gross examination revealed that the ICX-SKN skin graft replacement had integrated well in each of the six wounds and that re-epithelialization had occurred in each case. Histological analysis revealed that the ICX-SKN skin graft replacement remained in place and had become vascularized and provided a continuous wound closure. No serious adverse events were reported and no gross scarring or wound contracture was evident in the healed wounds.

CONCLUSION

This is the first report of preliminary evidence indicating the persistence of an autosynthesized, tissue-engineered, living human skin substitute in healed acute wounds in humans.

Evaluation of dermagraft as an alternative to grafting for open fasciotomy wounds

Wounds produced following open fasciotomy can be healed by grafting but this requires a second operation. Is Dermagraft, a tissue-engineered human fibroblast-derived dermis that can be applied on an outpatient basis, a viable alternative?

Management of leg ulcers

Leg ulcer is a leading cause of morbidity among older subjects, especially women in the Western world. About 400 years BC, Hippocrates wrote, "In case of an ulcer, it is not expedient to stand, especially if the ulcer be situated on the leg". Hippocrates himself had a leg ulcer. The best treatment of any leg ulcer depends upon the accurate diagnosis and the underlying aetiology. The majority of leg ulcers are due to venous disease and/or arterial disease, but the treatment of the underlying cause is far more important than the choice of dressing. The aetiology, pathogenesis, treatment, and the future trends in the management of the leg ulcers are discussed in this review.

Graftskin heals an ulcer on an amputation stump

BACKGROUND

A 51-year-old man presented with a chronic ulcer of 28 years' duration on the amputation stump of his right foot. The prosthesis was aggravating the ulcer, despite multiple therapies.

OBJECTIVE

To heal the ulcer and avoid a below-the-knee amputation. Graftskin, a bilayered living skin construct, was applied.

METHODS

Graftskin was sutured in place following gentle debridement. Pentoxifylline was given to improve circulation. The dressing was changed 5 days after Graftskin application, then weekly for 7 weeks.

RESULTS

Crusting was evident at 3 weeks, with an underlying white coating at 4 weeks. By 7 weeks, full reepithelialization was present under the crust and no ulceration remained. Over succeeding weeks the ulcer bed became flush with the surrounding skin. The patient's pain ceased, and some sensation and warmth returned to the stump.

CONCLUSION

Graftskin treatment successfully healed a chronic ulcer, possibly preventing a more extensive amputation.