Bone marrow transplantation in epidermolysis bullosa

Needle-free cutaneous delivery of living human cells by Er:YAG fractional laser ablation

BACKGROUND

Dermatological diseases, including most skin cancers and rare genetic conditions frequently originate in the epidermis. Targeted, topical cell-based therapy is a promising therapeutic strategy. Here, we present the first report demonstrating that fractional laser ablation enables local 'needle-free' intraepidermal delivery of living human cells.

METHODS

The cells penetrated porcine ear skin via microchannels created by Er:YAG fractional laser ablation; cell delivery was quantified using a haemocytometer. Cutaneous distribution was confirmed visually by laser scanning confocal microscopy and histological analysis.

RESULTS

Total cell delivery (sum of amounts permeated and deposited) after 24 h increased from 5.7 ± 0.1 x10⁵ to 9.6 ± 1.6 x10⁵ cells/cm² when increasing pore density from 300 to 600 pores/cm², - corresponding to 19- and 32-fold increases over the control. At 600 pores/cm², cell deposition was 136-fold greater than cell permeation - the latter most likely due to transport from micropores into appendageal pathways. Production of GFP post-delivery confirmed cell remained viability.

CONCLUSION

The results demonstrate the feasibility of using controlled laser microporation to achieve local 'needle-free' cutaneous delivery of living human cells to the epidermis and dermis. This raises the possibility of using this technique for targeted new approaches for dermatological therapy in these regions.

Modulating the stem cell niche for tissue regeneration

The field of regenerative medicine holds considerable promise for treating diseases that are currently intractable. Although many researchers are adopting the strategy of cell transplantation for tissue repair, an alternative approach to therapy is to manipulate the stem cell microenvironment, or niche, to facilitate repair by endogenous stem cells. The niche is highly dynamic, with multiple opportunities for intervention. These include administration of small molecules, biologics or biomaterials that target specific aspects of the niche, such as cell-cell and cell-extracellular matrix interactions, to stimulate expansion or differentiation of stem cells, or to cause reversion of differentiated cells to stem cells. Nevertheless, there are several challenges in targeting the niche therapeutically, not least that of achieving specificity of delivery and responses. We envisage that successful treatments in regenerative medicine will involve different combinations of factors to target stem cells and niche cells, applied at different times to effect recovery according to the dynamics of stem cell-niche interactions.

Allogeneic blood and bone marrow cells for the treatment of severe epidermolysis bullosa: repair of the extracellular matrix

Contrary to the prevailing professional opinion of the past few decades, recent experimental and clinical data support the fact that protein replacement therapy by allogeneic blood and marrow transplantation is not limited to freely diffusible molecules such as enzymes, but also large structural proteins such as collagens. A prime example is the cross-correction of type VII collagen deficiency in generalised severe recessive dystrophic epidermolysis bullosa, in which blood and marrow transplantation can attenuate the mucocutaneous manifestations of the disease and improve patients' quality of life. Although allogeneic blood and marrow transplantation can improve the integrity of the skin and mucous membranes, today's accomplishments are only the first steps on the long pathway to cure. Future strategies will be built on the lessons learned from these first transplant studies.