Dilip Shah

Facilitation of transcutaneous drug delivery and vaccine immunization by a safe laser technology

Full-surface laser ablation has been shown to efficiently disrupt stratum corneum and facilitate transcutaneous drug delivery, but it is frequently associated with skin damage that hampers its clinic use. We show here that a safer ablative fractional laser (AFL) can sufficiently facilitate delivery of not only patch-coated hydrophilic drugs but also protein vaccines. AFL treatment generated an array of self renewable microchannels (MCs) in the skin, providing free paths for drug and vaccine delivery into the dermis while maintaining integrity of the skin by quick healing of the MCs. AFL was superior to tape stripping in transcutaneous drug and vaccine delivery as a much higher amount of sulforhodamine B (SRB), methylene blue (MB) or a model vaccine ovalbumin (OVA) was recovered from AFL-treated skin than tape-stripped skin or control skin after patch application. Following entry into the MCs, the drugs or OVA diffused quickly to the entire dermal tissue via the lateral surface of conical-shaped MCs. In contrast, a majority of the drugs and OVA remained on the skin surface, unable to penetrate into the dermal tissue in untreated control skin or tape stripping-treated skin. Strikingly, OVA delivered through the MCs was efficiently taken up by epidermal Langerhans cells and dermal dendritic cells in the vicinity of the MCs or transported to the draining lymph nodes, leading to a robust immune response, in sharp contrast to a weak, though significant, immune response elicited in tape stripping group or a basal immune response in control groups. These data support strongly that AFL is safe and sufficient for transcutaneous delivery of drugs and vaccines.

A micro-sterile inflammation array as an adjuvant for influenza vaccines

There is an urgent need of adjuvants for cutaneous vaccination. Here we report that micro-sterile inflammation induced at inoculation sites can augment immune responses to influenza vaccines in animal models. The inoculation site is briefly illuminated with a handheld, non-ablative fractional laser before the vaccine is intradermally administered, which creates an array of self-healing microthermal zones (MTZs) in the skin. The dying cells in the MTZs send “danger” signals that attract a large number of antigen-presenting cells, in particular, plasmacytoid dendritic cells (pDCs) around each MTZ forming a micro-sterile inflammation array. A pivotal role for pDCs in the adjuvanticity is ascertained by significant abrogation of the immunity after systemic depletion of pDCs, local application of a TNF-α inhibitor, or null mutation of IFN regulatory factor7 (IRF7). In contrast to conventional adjuvants that cause persistent inflammation and skin lesions, micro-sterile inflammation enhances efficacy of influenza vaccines, yet with diminished adverse effects.

Altered redox state and apoptosis in the pathogenesis of systemic lupus erythematosus

An altered redox status and increased lymphocyte apoptosis have been implicated in the development of systemic lupus erythematosus (SLE). In this study, we evaluated the relationship between glutathione (GSH) depletion, reactive oxygen species (ROS) and, the progression of apoptosis and their association with SLE severity. Significant low levels of intracellular glutathione, total thiol and altered redox state (GSH/GSSG) were found in SLE patients, in which lymphocyte apoptosis and activated caspase-3 expression in the lymphocytes were remarkably increased. The severity of disease was positively allied with the increased levels of lymphocyte apoptosis and caspase-3, but negatively with the decreased levels of total thiol, depleted intracellular glutathione and altered redox state (GSH/GSSG). The lymphocyte apoptosis and activated caspase-3 expression were negatively associated with intracellular levels of GSH and redox state and positively associated with the elevated levels of multiple oxidative stress markers; ROS and lipid peroxidation measured as malondialdehyde (MDA). These results suggest that GSH depletion and elevated oxidative stress trigger apoptosis and may be coupled with the severity of the disease.

An update on the use of laser technology in skin vaccination.

Vaccination via skin often induces stronger immune responses than via muscle. This, in line with potential needle-free, painless delivery, makes skin a very attractive site for immunization. Yet, despite decades of effort, effective skin delivery is still in its infant stage and safe and potent adjuvants for skin vaccination remain largely undefined. We have shown that laser technologies including both fractional and non-fractional lasers can greatly augment vaccine-induced immune response without incurring any significant local and systemic side effects. Laser illumination at specific settings can accelerate the motility of antigen-presenting cells or trigger release of ‘danger’ signals stimulating the immune system. Moreover, several other groups including the authors explore laser technologies for needle-free transcutaneous vaccine delivery. As these laser-mediated resurfacing technologies are convenient, safe and cost-effective, their new applications in vaccination warrant clinical studies in the very near future.