Robert G. Phelps

A Phase 1/2 Clinical Trial of Enzyme Replacement in Fabry Disease: Pharmacokinetic, Substrate Clearance, and Safety Studies

Fabry disease results from deficient alpha-galactosidase A (alpha-Gal A) activity and the pathologic accumulation of the globotriaosylceramide (GL-3) and related glycosphingolipids, primarily in vascular endothelial lysosomes. Treatment is currently palliative, and affected patients generally die in their 40s or 50s. Preclinical studies of recombinant human alpha-Gal A (r-halphaGalA) infusions in knockout mice demonstrated reduction of GL-3 in tissues and plasma, providing rationale for a phase 1/2 clinical trial. Here, we report a single-center, open-label, dose-ranging study of r-halphaGalA treatment in 15 patients, each of whom received five infusions at one of five dose regimens. Intravenously administered r-halphaGalA was cleared from the circulation in a dose-dependent manner, via both saturable and non-saturable pathways. Rapid and marked reductions in plasma and tissue GL-3 were observed biochemically, histologically, and/or ultrastructurally. Clearance of plasma GL-3 was dose-dependent. In patients with pre- and posttreatment biopsies, mean GL-3 content decreased 84% in liver (n=13), was markedly reduced in kidney in four of five patients, and after five doses was modestly lowered in the endomyocardium of four of seven patients. GL-3 deposits were cleared to near normal or were markedly reduced in the vascular endothelium of liver, skin, heart, and kidney, on the basis of light- and electron-microscopic evaluation. In addition, patients reported less pain, increased ability to sweat, and improved quality-of-life measures. Infusions were well tolerated; four patients experienced mild-to-moderate reactions, suggestive of hypersensitivity, that were managed conservatively. Of 15 patients, 8 (53%) developed IgG antibodies to r-halphaGalA; however, the antibodies were not neutralizing, as indicated by unchanged pharmacokinetic values for infusions 1 and 5. This study provides the basis for a phase 3 trial of enzyme-replacement therapy for Fabry disease.

Isoflavone Genistein: Photoprotection and Clinical Implications in Dermatology

Genistein is a soybean isoflavone with diverse biological activities. It is a potent antioxidant, a specific inhibitor of protein tyrosine kinase, and a phytoestrogen. In recent years, increasing evidence has accumulated that this natural ingredient shows preventative and therapeutic effects for breast and prostate cancers, postmenopausal syndrome, osteoporosis, and cardiovascular diseases in animals and humans. In the past decade we have conducted a series of studies and demonstrated that genistein has significant antiphotocarcinogenic and antiphotoaging effects. Genistein substantially inhibits skin carcinogenesis and cutaneous aging induced by ultraviolet (UV) light in mice, and photodamage in humans. The mechanisms of action involve protection of oxidative and photodynamically damaged DNA, downregulation of UVB-activated signal transduction cascades, and antioxidant activities. In this article, we review the biological activities of genistein, as well as published and unpublished research from our laboratory. In addition, we discuss the potential application of genistein to clinical dermatology.

Clinical, histologic and electron microscopic findings after injection of a calcium hydroxylapatite filler

BACKGROUND: Calcium hydroxylapatite (CaHa) is one of many newly available soft tissue fillers. OBJECTIVE: We have, in this pilot study, evaluated the clinical, histologic and electron microscopic ultrastructural changes seen with CaHa at 1 and 6 months after skin injection. METHODS: Each of the three subjects was injected in the postauricular area with 0.1 cc of CaHa gel. A 3‐mm punch tissue biopsy was taken at 1 and 6 months post‐injection. Biopsies were analyzed by histopathology and electron microscopy. Clinical results after injection of the nasolabial folds were also evaluated. RESULTS: CaHa particles were found to persist at 6 months with evidence of new collagen formation being seen. Patients still showed clinical improvement at this time. CONCLUSION: This study is the first in vivo ultrastructural analysis of the biologic response to CaHa in human skin. CaHa shows clinical, histologic and electron microscopic evidence of persistence at 6 months.

Disrupting the IL-4 gene rescues mice homozygous for the tight-skin mutation from embryonic death and diminishes TGF-β production by fibroblasts

The TSK/TSK mutation is embryonic lethal; embryos have been reported to die at 7–8 days of gestational age. Crossing TSK/+, IL-4+/− mice revealed that disrupting one or both IL-4 alleles allowed survival of 29 and 47%, respectively, of TSK/TSK mice. These mice failed to develop cutaneous hyperplasia but did exhibit the emphysema that is found in TSK/+ mice. We showed that IL-4 stimulation of fibroblasts increased the level of transforming growth factor-β (TGF-β) mRNA and that lungs of TSK/+, IL-4−/− mice had substantially less TGF-β mRNA than lungs of TSK/+, IL-4+/+ mice. Thus IL-4 seems to regulate the expression of TGF-β in fibroblasts, providing an explanation for the absence of cutaneous hyperplasia in TSK/+, IL-4Rα−/− and TSK/+, TGF-β+/− mice.

Histologic and ultrastructural analysis of melasma after fractional resurfacing.

Fractional photothermolysis is a popular treatment option for photodamaged skin and other cutaneous conditions. Recently, successful improvement in melasma has been achieved with this laser system. We undertook this study to evaluate the ultrastructural changes associated with fractional laser treatment of melasma.

Hypopigmented variant of mycosis fungoides: Demography, histopathology, and treatment of seven cases

BACKGROUND Hypopigmented macules have been described infrequently as a presenting form of mycosis fungoides (MF). OBJECTIVE This study was designed to clarify general characteristics of a hypopigmented MF variant. METHODS Seven new cases were investigated with the use of descriptive epidemiology techniques. Demographic parameters, histopathology, and treatment outcomes were analyzed. These data were combined with those from prior reports to develop a broad composite view of this disease process. RESULTS The median ages in our series were 36 years for disease onset and 39 years at biopsy diagnosis. All patients had brown or black skin. Histologic findings consistently showed a lack of epidermal atrophy and moderate to profound exocytosis. Treatment with PUVA induced rapid and complete repigmentation in six of seven patients. CONCLUSION On the basis of our experience and a literature review, the hypopigmented variant of MF occurs in a younger population than typical forms of the disease and affects persons with dark skin almost exclusively. Microscopic features include lack of epidermal atrophy and moderate to extreme epidermotropism of infiltrating mononuclear cells. The treatment of choice appears to be PUVA.

A Prospective Study of Fractional Scanned Nonsequential Carbon Dioxide Laser Resurfacing: A Clinical and Histopathologic Evaluation

BACKGROUND Although unparalleled in its efficacy, carbon dioxide (CO2) laser resurfacing has a high risk:benefit ratio. A modified device uses a novel handpiece and software to deliver nonsequential fractional ablative CO2 laser exposures. OBJECTIVE To evaluate the safety and efficacy of this fractional ablative, scanned, nonsequential CO2 laser in the treatment of photo‐damaged skin and to evaluate histologic and ultrastructural changes after the treatment. MATERIALS AND METHODS Ten subjects with Fitzpatrick skin types I to III with photo‐damaged facial skin underwent a single CO2 ablative laser treatment using a scanning handpiece in a nonsequential fractional mode. Clinical improvement and histologic and ultrastructrural changes were assessed. RESULTS All subjects completed the study with no serious or long‐term complications. Blinded evaluator and subject assessment documented improvement in cutaneous photoaging. Light microscopy revealed changes consistent with a wound repair mechanism, and electron microscopy confirmed evidence of new collagen deposition. CONCLUSION Nonsequential scanned fractional CO2 laser resurfacing can lead to improvement in photo‐damaged skin, accompanied by histologic and ultrastructural evidence of wound repair and subsequent new collagen formation. The study was supported in part by a grant from Lumenis Inc.

Ultrastructural changes seen after ALA‐IPL photorejuvenation: A pilot study

Background. Intense pulse light (IPL) treatment currently represents one of the most popular non‐ablative photodamage skin treatments. Recent anecdotal evidence suggests that aminolevulonic acid (ALA) photodynamic therapy using IPL as a light source is superior to IPL alone for photorejuvenation. Methods. Seven adult subjects (six women, one man) with minimal photodamage were treated with full face IPL treatment. Half of the face was pre‐treated with topical ALA. Pre‐and post‐treatment biopsies were analyzed for changes in collagen by electron microscopic ultrastructural analysis. Results. An increase in type I collagen fibers was seen after treatment in all subjects. There was a greater increase in type I collagen formation in those subjects who were pre‐treated with topical ALA. Conclusion. This small pilot study is the first to focus on the ultrastructural changes seen after ALA‐IPL photorejuvenation. We found a greater shift toward type I collagen synthesis in the ALA‐IPL group compared to the IPL group. The addition of ALA to IPL treatment for photorejuvenation may be superior to IPL alone.

Diagnosis of Pseudoxanthoma Elasticum by Scar Biopsy in Patients without Characteristic Skin Lesions

Pseudoxanthoma elasticum is a disorder of connective tissue that is associated with numerous systemic complications, including accelerated atherosclerosis, gastrointestinal bleeding, angioid streaks in the ocular fundus, and blindness. Diagnosis of the disease is important because many of its complications can be prevented and genetic counseling can be offered to family members of affected patients. The purpose of this study was to examine the usefulness of scar biopsy in establishing a diagnosis of pseudoxanthoma elasticum in patients with angioid streaks but without characteristic skin lesions. Ten patients with angioid streaks but without cutaneous findings indicative of pseudoxanthoma elasticum were evaluated by biopsy of scars and flexural skin. The biopsy specimens were compared with those from unaffected controls. In 6 of the 10 patients, scar biopsies showed fragmentation and clumping of elastic tissue in the deep dermis. Three patients also had these histologic features of pseudoxanthoma elasticum in biopsy specimens of flexural skin that appeared to be normal. We conclude that biopsies of scars in randomly chosen sites may be useful when pseudoxanthoma elasticum is suspected despite the absence of typical skin lesions.

Multiple hamartoma syndrome

Multiple hamartoma syndrome, also known as Cowdens disease, is a rare genodermatosis with multiple organ system involvement affecting tissues derived from ectodermal, endodermal, and mesodermal tissue layers. We describe two previously unreported cases of multiple hamartoma syndrome in a father and daughter. Both show classic features of multiple hamartoma syndrome, as well as other mucocutaneous findings. The father has been shown to have substantial cutaneous deposits of amyloid in the absence of underlying plasma cell dyscrasia or malignancy. Both individuals have undergone excision of a unique fibroma that has features that have been reported only in multiple hamartoma syndrome and should be added to the criteria used to define the entity.