Adventures in research of a community-based dermatologist: Severity in acne – measurement and meaning.
The severity of acne, as for many other skin diseases, is multidimensional - comprising primary signs of active disease, its secondary effects, impact on quality of life, and treatment recalcitrance. The patient reported perspective of illness is a critical but previously neglected component of this paradigm. The quality of life impact of acne cannot be predicted from clinical severity as those most severely impacted differ from those most severely affected. Furthermore, adherence to topical acne treatment increases for those with increasing quality of life impact, while it diminishes for those with increasing clinical severity.
While clinicians are expert in assessing the clinical features of skin disease including primary and secondary changes in the skin, the current challenge is to incorporate these disparate elements with relevant and validated measures that are practical for use in routine clinical practice. In acne evaluations, the comprehensive acne severity scale (CASS) for primary lesions and activity of acne at face and trunk is a validated and practical instrument for clinicians that provides a measure of clinical severity beyond facial grading. A scale for acne scarring has been also developed using a similar scale. While many acne quality of life instruments are available, the vast majority are lengthy and few are validated. The validated Acne Q4, however, comprising only 4 items, is brief and practical.
The perspective of the physician and the patient of the impact of acne are complementary but potentially disparate. Measuring these dimensions of dermatological disease with validated instruments provides a means by which further research on patient centred care may be facilitated.
Neighbourly Communications Between Keratinocytes: Relevance of Cross Talk Between Proteins and Lipids to Malignancy
Gilles J. Lauzon MD FRCPC, Division of Dermatology, University of Alberta, Edmonton, AB, Canada
CDF Lecture 2006
CDA 81st Annual Conference
The Fort Garry Hotel, Winnipeg, Manitoba, Canada
The classical cadherins, cell-cell adhesion molecules that comprise adherens junctions, are strategically involved in cellular morphology, proliferation, differentiation and apoptosis. In the epidermis, supra-basal keratinocytes and melanocytes express E-cadherin, a protein essential for the maintenance of epidermal architecture and an important determinant of cellular behavior. The loss of expression of E-cadherin (epithelial cadherin) and the surrogate expression of N-cadherin (neuronal cadherin) often accompany the malignant degeneration of keratinocytes and melanocytes, resulting in phenotyic epithelioid-to-mesenchymal transition (EMT). The dominance of N-cadherin and resulting EMT bestow on malignant keratinocytes and melanocytes the ability to sever their neighbourly interactions with surrounding normal cells, thus disturbing tissue architecture and permitting metastasis.
We have shown that a clone of SCC9 squamous carcinoma cells (termed SCC9-AS) derived from a primary tongue carcinoma is devoid of E-cadherin, expresses N-cadherin and displays a mesenchymal (fibroblastoid) phenotype. The forced expression of E-cadherin in SCC9-A5 cells using genetic constructs profoundly alters their phenotype and biology, resulting in the loss of expression of N-cadherin, adoption of an epithelioid (cobblestone) phenotype, contact inhibition of growth, enhanced susceptibility to staurosporine-induced apoptosis and decreased susceptibility to TRAIL-induced apoptosis, a composite of the features of "normal" epithelial cells. Forced expression of a construct lacking the C-terminus of E-cadherin showed this domain to be essential for the down-regulation of N-cadherin.
Sphingolipids also affect cellular proliferation, differentiation, morphology and apoptosis; the inter-convened sphingolipids ceramide and sphingosine-1-phosphate (S-l-P) mediate opposing effects on these processes:
Our research has demonstrated a link between effects mediated by classical cadherins and sphingolipids at the level of sphingosine kinase-1 (SphK-1), an enzyme that mediates S-l-P synthesis from sphingosine. We have shown 1) the protein kinase C (PKC)-dependent formation of complexes comprised of E-cadherin, PKC, SphK-l and actin; 2) the PKC-dependent phosphorylation of SphK-l; and 3) the mediation of some effects of E-cadherin on cell morphology and proliferation via pathways involving SphK-1 through the use of SphK inhibitors and a dominant negative, enzymatically-inactive genetic construct of SphK-1.
N-cadherin expression and EMT, conjugates of epithelial malignancy, tissue disruption, enhanced growth and metastatic potential, thus involve sphingolipid inter-conversions that offer potential therapeutic targets for the chemotherapy of malignancies of keratinocytes and melanocytes. Of relevance, the pharmacological interruption of N-cadherin signaling has been suggested as a therapeutic strategy for the treatment of melanoma.
Our group has studied the ability of photodynamic therapy (PDT) to prevent skin cancer using murine models. In these experiments groups of hairless mice are exposed to UV radiation on a daily basis and concomitantly treated weekly with large surface topical PDT. Using this experimental design we have shown that weekly large surface PDT performed with aminolevulinic acid (ALA) can delay the appearance of actinic keratoses as well as squamous cell carcinoma.
We recently conducted experiments where mice were first exposed to UV radiation for 8 weeks followed by weekly ALA-PDT performed with a Blu-U (unit used in the clinic to treat patients with actinic keratoses). Using this sequential approach we were able again to delay the appearance of actinic keratoses and squamous cell carcinoma. Although the hairless mouse is an excellent model for squamous cell carcinoma, basal cell carcinoma are not observed despite long term UV radiation exposure. The heterozygous PTCH mouse is a murine model that can develop basal cell carcinoma following chronic UV exposure. Using this mouse model and the topical photosensitizer methylaminolevulinate we have shown that weekly PDT can also delay the appearance of basal cell carcinoma.
The mechanism of action of this delay probably involves a local phenomenon as it is only observed on areas where the topical photosensitizer is applied. In experiments where mice were exposed chronically UV radiation and treated once with ALA-PDT we have observed that ALA-PDT does not seem to induce a delay in skin cancer appearance by direct phototoxicity on clusters of mutated p53 cells which are believed to represent microscopic precursors of actinic keratoses. Clinicians have recently started to use broad area ALA-PDT for the treatment of actinic keratoses as well as photoaging. Our animal data suggests that this approach may also have the added benefit of skin cancer prevention.
Old Wine In New Bottles: Reviving Old Therapies for Alopecia Areata
Jerry Shapiro, MD FRCPC et al
University of British Columbia Hair Research and Treatment Centre, Vancouver General
Hospital, Vancouver, BC, Canada
Introduction: Alopecia areata (AA) is regarded as a tissue restricted autoimmune disease of hair follicles in which follicular activity is arrested due to the continued activity of a lymphocytic cellular infiltrate.
The use of valid animal models provide a tool to dissect out molecular mechanisms of therapeutic effects. Time-honored dermatologic treatments such as anthralin and mechlorethamine have been used in the treatment of AA, but efficacy and mechanism of action has not been studied in any great detail.
Methods: Mice and rats with alopecia areata were treated topically with anthralin and mechlorethamine on one side of the dorsal surface. RNAase protection assay, RT-PCR, genomic and proteomic analysis were performed on both treated and non-treated sides. Humans were also treated in a unilateral manner with both agents.
Results and Condusions: All rats and mice responded to topical treatment. Twenty to twenty five percent of humans responded to the above treatments. In the animal models, certain cytokines were consistently upregulated (IL-1 a/b, IL-10) or down-regulated (IFN-g and TNF-a).
Genomic profiling also showed modifications of expression of certain genes. Immuno-histochemistry showed migration or total depletion of folliculocentric CD8 and CD4 populations. CD54 or ICAM-1 showed similar changes. Proteomics showed certain proteins related to cellular proliferation or apoptosis were altered. Studying the molecular mechanisms regulating follicular activity in animal models using some of these time-honored dermatologic treatments can potentially give us insight with respect to mechanism of action.
Targeting specific cytokines such as IFN-g and TNF-a using the new biologics may have great potential in the treatment of AA. These visible, accessible, and unilaterally treated animal model systems are ideal to study novel AA therapies as well as the in vivo molecular mechanisms of therapeutic actions.
In Vivo Confocal Scanning Laser Microscopy of Benign and Malignant Pigmented Lesions
Dr Richard D. B. Langley, FRCP, Dalhousie University, Halifax, NS Recipient of the CDF-Galderma Canada Research Grant 2002
Skin cancer is the most common cancer in Canada and the United States. Melanoma is one of the most lethal types of skin cancer, and is a malignancy that is characterized by the uncontrolled growth of pigment-producing cells called melanocytes.
The Canadian Cancer Society estimates 70,000 individuals will develop non-melanoma skin cancer and 3,800 will develop cutaneous melanoma in Canada in the year 2001. The incidence of melanoma is increasing faster than any other malignancy in persons with light colored skin in all parts of the world.
Nova Scotia has the highest incidence of melanoma in Canada. The Canadian Cancer Society has estimated the age-standardized incidence rate for melanoma will be 22/100,000 for males (Canadian total is 12/100,000) and 17/100,000 for females (Canadian total is 10/100,000) in 2001.
When detected early, surgical removal of thin melanomas can cure the disease in most cases. Early detection is essential; there is a direct correlation between the thickness of the melanoma and survival rate. If melanoma is detected when it is completely flat (melanoma in situ) it is almost always curable.
If it is detected and removed when it is the thickness of a dime (~1.0 mm) the cure rate is approximately 90%. If however it becomes as thick as four dimes (~4.0 mm) the cure rate is in the order of 50%.
Despite the importance of early recognition, physicians' ability to recognize these lesions is less than perfect. Currently, the only way to diagnose skin cancer is to surgically remove a portion of the lesion or the entire lesion. This may lead to removal of unnecessary lesions or failure to remove a lesion that is cancerous. This has prompted the development of non-invasive techniques to improve the early diagnosis. A new instrument, a laser confocal microscope, is capable of imaging living tissue at the cellular level.
Similar to how an MRI or CT scan can image gross anatomical structures of the body, the confocal microscope provides rapid, non-invasive in vivo images of human skin showing cellular and nuclear detail and morphology. Such techniques may provide a "window" into living tissue and a non-invasive pathological examination of tissue. By using lasers, it may be possible to detect cancer without having to take biopsies.
We are investigating the clinical use of the laser microscope to determine if it is possible to distinguish between benign and malignant skin lesions Our initial research indicates that it may be possible to detect cancer at an earlier stage when treatment is more likely to be successful. We hypothesize that the early diagnosis of melanoma will be improved by the introduction of new diagnostic methods involving the confocal microscope. These methods will simplify diagnosis, improve diagnostic accuracy, and reduce unnecessary biopsies.
Patients scheduled for biopsy of suspicious lesions will be recruited from dermatology clinics. They will undergo a clinical history, followed by clinical and dermoscopic examinations. Clinical and dermoscopic photographs of the lesions will be obtained. The lesions will then be imaged with the confocal microscope. Following the study, patients will undergo their previously scheduled biopsy. The lesions will be surgically removed and will be subjected to histopathological examination.
The results and measurements from the study examination will be compared to the results of the histological examination. If the confocal microscope is found to be as accurate as the histology, then the microscope may be considered an accurate diagnostic tool.
Because the CSLM is a non-invasive tool, there is little or no risk associated with a CSLM examination. Patients may suffer slight discomfort or anxiety. These risks are small in sight of the problems associated with biopsy, which include infection and scarring. A small investment of patients' time may result in the adoption of a faster, safer, non-invasive method of diagnosis.
CDF support for our research has been crucial to my development as an independent investigator. Grants received have provided infrastructure and enabled pilot research, which has led to successful external research funding. I am grateful for the private and industry support of the CDF.