Effect of pulsed dye laser on intercellular adhesion molecule-1 (ICAM-1) expression after treatment of psoriasis

Modeling pulsed dye laser treatment of psoriatic plaques by combining numerical methods and image-derived lesion morphologies

OBJECTIVES

Knowledge of the physical effects of pulsed dye laser (PDL) treatment of psoriatic lesions is essential in unraveling the remedial mechanisms of this treatment and hence also in maximizing in its disease-modifying potential. Therefore, the main objective of this study was to provide estimates of these physical effects (for laser wavelengths of 585 and 595 nm), with the aim of identifying pathogenic processes that may be affected by these conditions.

METHODS

We modeled the laser light propagation and subsequent photothermal heating by numerically solving the transient diffusion and heat equations simultaneously. To this end, we used the finite element method in conjunction with an image-derived psoriatic lesion morphology (which was defined by segmenting blood vessels from a confocal microscopy image of a fluorescently labeled section of a 3 mm punch biopsy of a psoriatic lesion). The resulting predictions of the generated temperature field within the lesion were then used to assess the possibility of stalling or arresting some suspected pathogenic processes.

RESULTS

According to our results, it is conceivable that perivascular nerves are thermally denatured, as almost all locations that reach 60°C were found to be within 18 µm (at 585 nm) and 11 µm (at 595 nm) of a blood vessel wall. Furthermore, activation of TRPV1 and TRPV2 channels in perivascular neuronal and immune cells is highly likely, since a critical temperature of 43°C is generated at locations within up to 350 µm of a vessel wall (at both wavelengths) and sustained for up to 700 ms (at 585 nm) and 40 ms (at 595 nm), while a critical temperature of 52°C is reached by locations within 80 µm (at 585 nm) and 30 µm (at 595 nm) of a vessel wall and sustained for up to 100  ms (at 585 nm) and 30 ms (at 595 nm). Finally, we found that the blood vessel coagulation-inducing temperature of 70°C is sustained in the vascular epithelium for up to 19 and 5 ms at 585 and 595 nm, respectively, rendering partial or total loss of vascular functionality a distinct possibility.

CONCLUSIONS

The presented approach constitutes a useful tool to provide realistic estimates of the photothermal effects of PDL treatment of psoriatic plaques (as well as other selective photothermolysis-based treatments), yielding information that is essential in guiding future experimental studies toward unraveling the remedial mechanisms of these treatments.

Effects of pulsed dye laser treatment in psoriasis: A nerve-wrecking process?

Pulsed dye laser (PDL) therapy can be effective in treating psoriasis, with a long duration of remission. Although PDL therapy, albeit on a modest scale, is being used for decades now, the underlying mechanisms responsible for the long-term remission of psoriasis remain poorly understood. The selective and rapid absorption of energy by the blood causes heating of the vascular wall and surrounding structures, like perivascular nerves. Several studies indicate the importance of nerves in psoriatic inflammation. Interestingly, denervation leads to a spontaneous remission of the psoriatic lesion. Among all dermal nerves, the perivascular nerves are the most likely to be affected during PDL treatment, possibly impairing the neuro-inflammatory processes that promote T-cell activation, expression of adhesion molecules, leukocyte infiltration and cytokine production. Repeated PDL therapy could cause a prolonged loss of innervation through nerve damage, or result in a 'reset' of neurogenic inflammation after temporary denervation. The current hypothesis provides strong arguments that PDL treatment affects nerve fibres in the skin and thereby abrogates the persistent and exaggerated inflammatory process underlying psoriasis, causing a long-term remission of psoriasis.

Evaluation of the effect of pulsed dye laser on chronic psoriatic plaque

BACKGROUND

Psoriasis is one of the most prevalent immune mediated skin diseases. Selective vascular destruction by pulsed dye laser is considered one of effective laser treatments.

OBJECTIVE

Evaluation of the therapeutic effect of pulsed dye laser in treatment of chronic psoriatic plaque lesions and changes in human beta defensin-2(HBD-2) expression in the psoriatic patients before and after treatment, with correlation to the clinical improvement.

METHODS

Twenty patients with psoriatic plaque on right side treated by laser and another plaque on left side similar in size and its severity score served as control receiving no treatment. Each patient received 3-4 sessions of pulsed dye laser 595 nm. Follow up was done for three months.

RESULTS

There was statistically significant difference between the two psoriatic plaques (untreated and treated; A and B; p = .004). There was significant decrease in HBD-2 expression after treatment. No recurrence was observed during follow up period.

CONCLUSION

The pulsed dye laser is safe, effective, and tolerable treatment for resistant stable localized plaque psoriasis with minimal side effects and prolonged recurrence period.

Diabetes Mellitus and Bone Regeneration: A Systematic Review and Meta-Analysis of Animal Studies

BACKGROUND

The regeneration of bone defects resulting from trauma, resection of tumors, infection, or congenital disease is a challenge, and bone grafts are utilized in a wide array of clinical settings to augment bone repair and regeneration. Diabetes mellitus (DM) is a chronic metabolic disease, which affects 8.3% of the world population, summing ∼387 million individuals. The consequences of the disease, for example, hyperglycemia, have been associated to a reduced capacity to form bone and poor bone quality, influencing bone healing. Our aim was to systematically review the literature to the effect of diabetic condition on bone regeneration in animal models, when using bone substitute materials from different origins, and perform a meta-analysis to quantitatively study the effect of DM on bone regeneration.

METHODS

An extensive search strategy was carried out through PubMed and EMBASE to identify the potential relevant studies published from database inception until July 1, 2015. Initially, the title and abstract of 1409 studies were screened, after which inclusion criteria sorted 29 studies for full-text evaluation. After using exclusion criteria, a final number of seven studies could be included in the review.

RESULTS

The seven included studies that passed our inclusion/exclusion criteria were all type 1 diabetes, comprising a total of 189 animals and 14 intrastudy comparisons. These studies presented a consistent and reduced risk of bias and showed a significant average effect size of -6.87% of bone formation for diabetes type 1 versus healthy condition [95% confidence interval: -10.55 to -3.18; I² = 87.4%; p = 0.0003].

INTERPRETATION

These findings prove that DM type 1 negatively influences bone formation compared with a healthy condition, irrespective of the bone substitute material used.