Denis Salomon

Heterogeneity and contact-dependent regulation of hormone secretion by individual B cells☆

A reverse hemolytic plaque assay was developed to visualize insulin release from individual adult pancreatic B cells. Cells obtained by mechanical dispersion of isolated rat islets of Langerhans were mixed with protein A-coated sheep red blood cells and incubated in the presence of an anti-insulin serum, under conditions known to affect insulin release. The cell mixture was further incubated with complement and finally fixed. Insulin release was revealed by the presence of hemolytic plaques which resulted from the complement-mediated lysis of red blood cells bearing insulin-anti-insulin complexes bound to protein A. Quantitation of hemolytic plaques around trypan blue-unstained and immunohistochemically identified B cells showed that stimulation of insulin release results in the recruitment of increasing numbers of secreting B cells as well as in the enhanced response of individual B cells. Reverse changes occur upon inhibition of insulin release. Comparison of freshly dispersed and one-day-cultured preparations did not reveal significant differences in the secretory response of undamaged B cells. In both preparations, single B cells responded to secretagogues in smaller proportions and to a lesser extent than clusters in which B cells had either maintained or restored contacts and junctional communication with their neighbours. However, the overall preponderant response of clusters was less than expected from the number of individually secreting B cells they contained. The data show that B cells are heterogeneous in terms of their ability to release insulin and provide evidence that cell-to-cell adhesion and/or junctional communication regulate hormone secretion from individual B cells.

An autologous epidermal equivalent tissue-engineered from follicular outer root sheath keratinocytes is as effective as split-thickness skin autograft in recalcitrant vascular leg ulcers

The outer root sheath of hair follicles plays an important role in epidermal regeneration in vivo. Keratinocytes isolated by explantation of outer root sheath tissue have extensive proliferative capacity irrespective of donor age, which probably depends on pluripotent epithelial stem cells residing in the outer root sheath. These keratinocytes can be organotypically grown to epidermal equivalents in vitro. We report here that in a multicenter, randomized phase II study, EpiDex™, a tissue‐engineered, fully differentiated autologous epidermal equivalent derived from keratinocytes of the outer root sheath of plucked anagen hair follicles, is as effective as split‐thickness skin autografting in the promotion of healing and complete closure of recalcitrant vascular leg ulcers. (WOUND REP REG 2003;11:248–252)

The Association of the Two Antimalarials Chloroquine and Quinacrine for Treatment-Resistant Chronic and Subacute Cutaneous Lupus erythematosus

Antimalarials are the first line in the treatment of chronic and subacute cutaneous lupus erythematosus (LE). However, some patients show either no or only minor improvement on antimalarial monotherapy. We treated 14 patients (9 with chronic LE and 5 with subacute cutaneous LE) who had poorly responded to chloroquine or hydroxychloroquine with an association of chloroquine and quinacrine. The initial dose was: chloroquine 100 mg 3x/day and quinacrine 65 mg 3x/day. The skin lesions improved significantly or cleared totally in 5 of the 9 patients with chronic LE and in all the 5 patients with subacute cutaneous LE. These findings suggest that a chloroquine-quinacrine combination may sometimes be superior to the usual antimalarial monotherapy, especially for subacute LE. If chloroquine or hydroxychloroquine fails to control chronic or subacute cutaneous LE, chloroquine-quinacrine is worthy to be tried.

Full-Field Optical Coherence Tomography: A New Technology for 3D High-Resolution Skin Imaging

Background/Aims: Full-field optical coherence tomography (FFOCT) is a new imaging technology that can provide 3D micron-level resolution and is suited for high-resolution imaging of biological tissue. The aim of this study was to evaluate its capacity and potential for imaging human epidermis and dermis and various skin pathologies in ex vivo and in vivo conditions. Methods: Non-fixed and fixed samples of normal and pathological skin and normal in vivo skin were imaged with a FFOCT system and compared to histological slides. Results: The epidermis and adnexae, the collagen bundles of the dermis and the hypodermis could be identified through architectural and cellular details. The pathological structures were distinguished from the normal structures and corresponded to their histopathological organization. Conclusion: FFOCT is a novel technology in the field of skin imaging that has the potential to be a relevant complement to existing non-invasive imaging modalities for clinical and cosmetic applications.

Enhanced Delivery of 5-Aminolevulinic Acid Esters by Iontophoresis In Vitro¶

Abstract The goals of this study were to quantitatively evaluate the iontophoretic delivery of a homologous series of cationic aminolevulinic acid (ALA) esters and to determine the contributions of electromigration and electroosmosis to their overall electrotransport in vitro. Anodal iontophoretic transport of ALA esters through porcine skin in vitro was followed for 2 h at a constant current of 0.5 mA/cm2. To deduce the mechanism, the concomitant transport of an electroosmotic marker, mannitol, was also assessed. Positively charged ALA esters of moderate lipophilicity showed increased iontophoretic flux through the skin. A more than 50-fold enhancement as compared with the zwitterionic parent ALA was observed for the methyl ester. As the size and lipophilicity of the ester increased, the efficiency of electrotransport decreased. The most lipophilic esters reduced the electroosmotic flow presumably because of the association of these cations with negative charges in the skin. Iontophoresis of methyl-ALA and hexyl-ALA also increased the amount of prodrug delivered into the skin. In summary, significant topical delivery of ALA esters can be achieved by iontophoresis, and transport into and across the skin was greatly enhanced compared with that of ALA itself. It remains to be seen whether this enhanced local bioavailability of the protoporphyrin prodrug can allow improved photodynamic therapy for the treatment of skin cancer.

Pulse of methylprednisolone in alopecia areata.

In an attempt to stop the evolution of recent-onset severe alopecia areata (AA), we tested pulse corticotherapy on 9 patients. Acceptance into the study was based on the following criteria: recent-onset AA (< 1 year), AA in an active state, bald surface > 30% of the scalp, no contraindication to pulse corticotherapy. Each patient was given 250 mg i.v. of methylprednisolone twice a day on 3 successive days. In 8 patients the course of the ongoing episode of AA was stopped. At the 6-month follow-up, a regrowth on 80-100% of the bald surface was observed in 6 patients. One patient did not respond to treatment, and 2 had less than 50% of regrowth. This open study suggests that pulse corticotherapy: (1) can stop the course of severe AA in an active state, (2) is well tolerated without major side effects and (3) does not permit a stable control of AA of more than 1 year duration. This treatment seems to be indicated for severe AA of recent onset.

In vivo Bio-Integration of Three Hyaluronic Acid Fillers in Human Skin: A Histological Study

Background: Hyaluronic acid (HA) formulations are used for aesthetic applications. Different cross-linking technologies result in HA dermal fillers with specific characteristic visco-elastic properties. Objective: Bio-integration of three CE-marked HA dermal fillers, a cohesive (monophasic) polydensified, a cohesive (monophasic) monodensified and a non-cohesive (biphasic) filler, was analysed with a follow-up of 114 days after injection. Our aim was to study the tolerability and inflammatory response of these fillers, their patterns of distribution in the dermis, and influence on tissue integrity. Methods: Three HA formulations were injected intradermally into the iliac crest region in 15 subjects. Tissue samples were analysed after 8 and 114 days by histology and immunohistochemistry, and visualized using optical and transmission electron microscopy. Results: Histological results demonstrated that the tested HA fillers showed specific characteristic bio-integration patterns in the reticular dermis. Observations under the optical and electron microscopes revealed morphological conservation of cutaneous structures. Immunohistochemical results confirmed absence of inflammation, immune response and granuloma. Conclusion: The three tested dermal fillers show an excellent tolerability and preservation of the dermal cells and matrix components. Their tissue integration was dependent on their visco-elastic properties. The cohesive polydensified filler showed the most homogeneous integration with an optimal spreading within the reticular dermis, which is achieved by filling even the smallest spaces between collagen bundles and elastin fibrils, while preserving the structural integrity of the latter. Absence of adverse reactions confirms safety of the tested HA dermal fillers.

Orbital and palpebral paraffinoma

Paraffinoma is a well-recognized complication of paraffin injection. We describe a 44-year-old man who had an ethmoidectomy for chronic sinusitis. A communicating fracture of the ethmoid bone into the orbit occurred intraoperatively. The nasal cavity was subsequently packed with gauze containing a petrolatum-based antibiotic ointment. Bilateral, periocular swelling developed 1 week later. Optical and electron microscopic studies revealed a paraffinoma.

Comparison of ALA- and ALA hexyl-ester-induced PpIX depth distribution in human skin carcinoma.

Photodynamic therapy (PDT) based on the use of photoactivable porphyrins, such as protoporphyrin IX (PpIX), induced by the topical application of amino-levulinic acid (ALA) or its derivatives, ALA methyl-ester (m-ALA), is a treatment for superficial basal cell carcinoma (BCC), with complete response rates of over 80%. However, in the case of deep, nodular-ulcerative lesions, the complete response rates are lower, possibly related to a lower bioavailability of PpIX. Previous in vitro skin permeation studies demonstrated an increased penetration of amino-levulinic acid hexyl-ester (h-ALA) over ALA. In this study, we tested the validity of this approach in vivo on human BCCs. An emulsion containing 20% ALA (w/w) and preparations of h-ALA at different concentrations were applied topically to the normal skin of Caucasian volunteers to compare the PpIX fluorescence intensities with an optical fiber-based spectrofluorometer. In addition, the PpIX depth distribution and fluorescence intensity in 26 BCCs were investigated by fluorescence microscopy following topical application of 20% ALA and 1% h-ALA. We found that, for application times up to 24h, h-ALA is identical to ALA as a PpIX precursor with respect to PpIX fluorescence intensity, depth of penetration, and distribution in basal cell carcinoma, but has the added advantage that much smaller h-ALA concentrations can be used (up to a factor 13). We observed a non-homogenous distribution in BCCs with both precursors, independent of the histological type and depth of invasion in the dermis.

Oral gold therapy (Auranofin) in pemphigus vulgaris.

Auranofin (AF), an oral gold salt, was given for 9-18 months to 3 patients with pemphigus vulgaris. There was a slight improvement with significant oral pain relief in 2, and a complete remission in 1. Two patients including the one with the remission, subsequently flared up under AF therapy. Although AF is said to be better tolerated than parenteral gold this limited series suggests that it does not seem to have a superior therapeutic effect in PV.