Histological and transcriptional study of angiogenesis and lymphangiogenesis in uninvolved skin, acute pinpoint lesions and established psoriasis plaques: an approach of vascular development chronology in psoriasis

BACKGROUND

Dysregulation of angiogenesis and lymphangiogenesis could participate in psoriasis pathogenesis. Analysis of nascent psoriasis lesions should help at identifying early vascular anomalies.

OBJECTIVE

To analyse vascular development, angiogenesis and lymphangiogenesis markers expression in uninvolved skin in psoriatic patients (N), early psoriasis lesions or pinpoints (PP) and psoriasis plaques (PSO).

METHODS

Skin biopsies were taken in 17 patients in N and in PSO and/or PP. The mRNA steady-state level of angiogenesis and lymphangiogenesis markers was measured by RT-PCR. Immunohistochemistry was performed for von Willebrand factor, podoplanin, Ki-67 and VEGFR3. Blood (BV) and lymphatic (LV) vessels expansion was measured by computer-assisted morphometry.

RESULTS

Clinical and epidermal aspects indicated that PP are intermediate between N and PSO. While total BV area was already increased in PP similarly to PSO as compared to N, LV area in PP was intermediate between N and PSO. Mean LV size was identical in N and PP and increased in PSO, mean BV size in PP being intermediate between N and PSO. VEGF-A 189 variant was increased in PP as compared to N and PSO. As compared to N, angiogenesis markers (VEGF-A isoforms, PlGF, VEGFR2, NRP-1), VEGF-C and NRP-2 were similarly increased in PP and PSO. Keratin 16 and the lymphangiogenesis markers (VEGFR3, prox-1) were intermediate in PP.

CONCLUSION

These data suggest that the expansion of lymphatic vessels occurs after blood vascular development in psoriasis. Expansion of BV in PP could be followed by vessel enlargement during progression to PSO, in parallel with a decreased VEGF-A 189/VEGF-A 121 balance in plaques.

[Biological therapy of inflammatory diseases]

The pathophysiology and the treatment of diseases with clinical presentation so different as rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and psoriasis vulgaris have been revolutionized by the discovery of common pro-inflammatory effector mechanisms involving TNF-alpha and by the use of targeted therapies, the anti-TNF-alpha antibodies. In the past 10 years, our experience has helped several hundreds of patients who were treated with novel drugs, years before they became routinely available. In parallel tools of metrology were developped that can now be applied to the routine patient. Lastly, clinical research on these new drugs has also generated derived research works allowing the university hospital to satisfactorilly fullfil its specific missions.

[Psoriasis and psoriatic arthritis]

Psoriasis is a frequent multifactorial chronic skin disease that can lead to a decreased quality of life. Some patients also present arthritis. Those two complex inflammatory diseases share some of their characteristics, but several clinical manifestations can be distinguished in each of them. In addition to classical medications (constituted of topical treatments, methotrexate, ciclosporin and retinoids for cutaneous psoriasis and non steroidal anti-inflammatory drugs or methotrexate for psoriatic arthritis), they are the target of a new generation of therapies: the biologics.

[Place of ivermectin in the treatment of scabies]

Ivermectin is the first oral treatment available for scabies. It is however not licensed for use in Belgium. In this article, we review its mechanism of action, its preferential indications among which crusted scabies and institutional outbreaks, its contra-indications and its advantages in comparison with topical treatments.

[Non bullous impetigo: streptococcal or staphylococcal?]

Non bullous impetigo is very common among the pediatric population. It is caused by bacteria. For twenty years, Staphylococcus aureus has been the most frequently isolated organism (present in 80 % of non bullous impetigo lesions, it is the only pathogen cultured in 50 % of patients). The group A beta-haemolytic streptococcus is at the moment isolated alone in 3% of lesions and in association with S. Aureus in 30 % of patients. An epidemiologic change seems to have occurred. Until the early 1980s, group A beta-haemolytic streptococcus was indeed the most predominant etiologic agent causing non bullous impetigo. Unfortunately, the rate of resistance among staphylococci responsible of non bullous impetigo is increasing. As serious complications can follow this skin infection, an appropriate treatment is necessary combining local care, topical antibiotics and sometimes adjunction of systemic antibiotics.

[Medication of the month. Tazarotene 0.05%-0.1% (Zorac)]

Since April 28th, a new topical retinoid is available in Belgium: tazarotene (Zorac) gel (Pierre Fabre). It exists at two concentrations: 0.05% or 0.1%. It is the first receptor-selective topical retinoid. It is indicated in the treatment of plaque-type psoriasis. In the USA, tazarotene is also licensed for use in the treatment of acne and several studies show its efficacy for the treatment of other skin diseases like photodamage and ichthyoses.

S-acetyl-glutathione selectively induces apoptosis in human lymphoma cells through a GSH-independent mechanism

Reduced apoptosis is associated to cancer development. Agents able to restore the programmed cell death responsiveness of cancer cells are foreseen as potential effective cancer therapies. In this study, we report that a glutathione-S-derivative, S-acetyl-glutathione (Sag), induces significant apoptosis in three human lymphoma cell lines, including Daudi, Raji and Jurkat cells while it had no or little effect on either Hut-78 lymphoma cells or the normal BT lymphocytes. We used Annexin-V FACS analysis and DNA laddering to demonstrate that Sag activated apoptosis in the three sensitive cell lines in a dose- and time-dependent-fashion. Using mercury orange staining and FACS analysis, we showed that Sag generated an intracellular GSH depletion in Daudi, Raji and Jurkat cells but not in Hut-78 or the normal BT cells. These data provide direct evidence that Sag specifically activates programmed cell death in lymphoma cells through, at least in part, a depletion of intracellular GSH rather than an increase, as previously suggested. Because of its selective effect on cancer cells, Sag appears as a promising new lymphoma cell apoptosis inducer with potential clinical value for lymphoma patients.