Oral supplementation of inorganic pyrophosphate in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE; OMIM 264800) is a rare heritable multisystem disorder, characterized by ectopic mineralization affecting elastic fibres in the skin, eyes and the cardiovascular system. Skin findings often lead to early diagnosis of PXE, but currently, no specific treatment exists to counteract the progression of symptoms. PXE belongs to a group of Mendelian calcification disorders linked to pyrophosphate metabolism, which also includes generalized arterial calcification of infancy (GACI) and arterial calcification due to CD73 deficiency (ACDC). Inactivating mutations in ABCC6, ENPP1 and NT5E are the genetic cause of these diseases, respectively, and all of them result in reduced inorganic pyrophosphate (PPi ) concentration in the circulation. Although PPi is a strong inhibitor of ectopic calcification, oral supplementation therapy was initially not considered because of its low bioavailability. Our earlier work however demonstrated that orally administered pyrophosphate inhibits ectopic calcification in the animal models of PXE and GACI, and that orally given Na4 P2 O7 is absorbed in humans. Here, we report that gelatin-encapsulated Na2 H2 P2 O7  has similar absorption properties in healthy volunteers and people affected by PXE. The sodium-free K2 H2 P2 O7 form resulted in similar uptake in healthy volunteers and inhibited calcification in Abcc6-/- mice as effectively as its sodium counterpart. Novel pyrophosphate compounds showing higher bioavailability in mice were also identified. Our results provide an important step towards testing oral PPi in clinical trials in PXE, or potentially any condition accompanied by ectopic calcification including diabetes, chronic kidney disease or ageing.

Development of the BioHybrid Assay: Combining Primary Human Vascular Smooth Muscle Cells and Blood to Measure Vascular Calcification Propensity.

BACKGROUND: Vascular calcification is an active process that increases cardiovascular disease (CVD) risk. There is still no consensus on an appropriate biomarker for vascular calcification. We reasoned that the biomarker for vascular calcification is the collection of all blood components that can be sensed and integrated into a calcification response by human vascular smooth muscle cells (hVSMCs). METHODS: We developed a new cell-based high-content assay, the BioHybrid assay, to measure in vitro calcification. The BioHybrid assay was compared with the o-Cresolphthalein assay and the T50 assay. Serum and plasma were derived from different cohort studies including chronic kidney disease (CKD) stages III, IV, V and VD (on dialysis), pseudoxanthoma elasticum (PXE) and other cardiovascular diseases including serum from participants with mild and extensive coronary artery calcification (CAC). hVSMCs were exposed to serum and plasma samples, and in vitro calcification was measured using AlexaFluor®-546 tagged fetuin-A as calcification sensor. RESULTS: The BioHybrid assay measured the kinetics of calcification in contrast to the endpoint o-Cresolphthalein assay. The BioHybrid assay was more sensitive to pick up differences in calcification propensity than the T50 assay as determined by measuring control as well as pre- and post-dialysis serum samples of CKD patients. The BioHybrid response increased with CKD severity. Further, the BioHybrid assay discriminated between calcification propensity of individuals with a high CAC index and individuals with a low CAC index. Patients with PXE had an increased calcification response in the BioHybrid assay as compared to both spouse and control plasma samples. Finally, vitamin K1 supplementation showed lower in vitro calcification, reflecting changes in delta Agatston scores. Lower progression within the BioHybrid and on Agatston scores was accompanied by lower dephosphorylated-uncarboxylated matrix Gla protein levels. CONCLUSION: The BioHybrid assay is a novel approach to determine the vascular calcification propensity of an individual and thus may add to personalised risk assessment for CVD.

Genomics-based treatment in a patient with two overlapping heritable skin disorders: Epidermolysis bullosa and acrodermatitis enteropathica.

Next-generation sequencing (NGS) is helpful in diagnosing complex genetic disorders and phenotypes, particularly when more than one overlapping condition is present. From a large cohort of 362 families with clinical manifestations of skin and mucosal fragility, referred by several major medical centers, one patient was found by NGS to have two overlapping heritable skin diseases, recessive dystrophic epidermolysis bullosa (RDEB; COL7A1 mutations) and acrodermatitis enteropathica (AE; SLC39A4 mutations). The pathogenicity of the variants was studied at gene expression as well as ultrastructural and tissue levels. Although there is no specific treatment for RDEB except avoiding trauma, supplementation with oral zinc (3 mg·kg-1 ·day-1 ) for the AE resulted in rapid amelioration of the skin findings. This case demonstrates the power of NGS in identifying two genetically unlinked diseases that led to effective treatment with major clinical benefits as an example of genomics-guided treatment.

Pseudoxanthoma Elasticum as a Paradigm of Heritable Ectopic Mineralization Disorders: Pathomechanisms and Treatment Development.

Ectopic mineralization is a global problem and leading cause of morbidity and mortality. The pathomechanisms of ectopic mineralization are poorly understood. Recent studies on heritable ectopic mineralization disorders with defined gene defects have been helpful in elucidation of the mechanisms of ectopic mineralization in general. The prototype of such disorders is pseudoxanthoma elasticum (PXE), a late-onset, slowly progressing disorder with multisystem clinical manifestations. Other conditions include generalized arterial calcification of infancy (GACI), characterized by severe, early-onset mineralization of the cardiovascular system, often with early postnatal demise. In addition, arterial calcification due to CD73 deficiency (ACDC) occurs late in life, mostly affecting arteries in the lower extremities in elderly individuals. These three conditions, PXE, GACI, and ACDC, caused by mutations in ABCC6, ENPP1, and NT5E, respectively, are characterized by reduced levels of inorganic pyrophosphate (PPi) in plasma. Because PPi is a powerful antimineralization factor, it has been postulated that reduced PPi is a major determinant for ectopic mineralization in these conditions. These and related observations on complementary mechanisms of ectopic mineralization have resulted in development of potential treatment modalities for PXE, including administration of bisphosphonates, stable PPi analogs with antimineralization activity. It is conceivable that efficient treatments may soon become available for heritable ectopic mineralization disorders with application to common calcification disorders.

Inhibition of Tissue-Nonspecific Alkaline Phosphatase Attenuates Ectopic Mineralization in the Abcc6-/- Mouse Model of PXE but Not in the Enpp1 Mutant Mouse Models of GACI.

Pseudoxanthoma elasticum (PXE), a prototype of heritable ectopic mineralization disorders, is caused by mutations in the ABCC6 gene encoding a putative efflux transporter ABCC6. It was recently shown that the absence of ABCC6-mediated adenosine triphosphate release from the liver and, consequently, reduced inorganic pyrophosphate levels underlie the pathogenesis of PXE. Given that tissue-nonspecific alkaline phosphatase (TNAP), encoded by ALPL, is the enzyme responsible for degrading inorganic pyrophosphate, we hypothesized that reducing TNAP levels either by genetic or pharmacological means would lead to amelioration of the ectopic mineralization phenotype in the Abcc6-/- mouse model of PXE. Thus, we bred Abcc6-/- mice to heterozygous Alpl+/- mice that display approximately 50% plasma TNAP activity. The Abcc6-/-Alpl+/- double-mutant mice showed 52% reduction of mineralization in the muzzle skin compared with the Abcc6-/-Alpl+/+ mice. Subsequently, oral administration of SBI-425, a small molecule inhibitor of TNAP, resulted in 61% reduction of plasma TNAP activity and 58% reduction of mineralization in the muzzle skin of Abcc6-/- mice. By contrast, SBI-425 treatment of Enpp1 mutant mice, another model of ectopic mineralization associated with reduced inorganic pyrophosphate, failed to reduce muzzle skin mineralization. These results suggest that inhibition of TNAP might provide a promising treatment strategy for PXE, a currently intractable disease.

Precision Medicine for Heritable Skin Diseases-The Paradigm of Epidermolysis Bullosa.

The 2016 JID Beijing Workshop, held in the context of the 5th National Congress of Investigative Dermatology of the Chinese Society of Dermatology, had the thematic focus on "Precision Medicine in Dermatology." This theme was extremely timely, yet forward-looking, due to the fact that precision medicine is one of the fastest growing paradigms of contemporary medicine (Box 1).

Elevated dietary magnesium during pregnancy and postnatal life prevents ectopic mineralization in Enpp1asj mice, a model for generalized arterial calcification of infancy.

Generalized arterial calcification of infancy (GACI) is an autosomal recessive disorder caused by mutations in the ENPP1 gene. It is characterized by mineralization of the arterial blood vessels, often diagnosed prenatally, and associated with death in early childhood. There is no effective treatment for this devastating disorder. We previously characterized the Enpp1asjmutant mouse as a model of GACI, and we have now explored the effect of elevated dietary magnesium (five-fold) in pregnant mothers and continuing for the first 14 weeks of postnatal life. The mothers were kept on either control diet or experimental diet supplemented with magnesium. Upon weaning at 4 weeks of age the pups were placed either on control diet or high magnesium diet. The degree of mineralization was assessed at 14 weeks of age by histopathology and a chemical calcium assay in muzzle skin, kidney and aorta. Mice placed on high magnesium diet showed little, if any, evidence of mineralization when their corresponding mothers were also placed on diet enriched with magnesium during pregnancy and nursing. The reduced ectopic mineralization in these mice was accompanied by increased calcium and magnesium content in the urine, suggesting that magnesium competes calcium-phosphate binding thereby preventing the mineral deposition. These results have implications for dietary management of pregnancies in which the fetus is suspected of having GACI. Moreover, augmenting a diet with high magnesium may be beneficial for other ectopic mineralization diseases, including nephrocalcinosis.

Molecular pathology of the basement membrane zone in heritable blistering diseases:: The paradigm of epidermolysis bullosa.

Epidermolysis bullosa (EB), a phenotypically heterogeneous group of skin fragility disorders, is characterized by blistering and erosions with considerable morbidity and mortality. Mutations in as many as 18 distinct genes expressed at the cutaneous basement membrane zone have been shown to be associated with the blistering phenotype, attesting to the role of the corresponding proteins in providing stable association of the epidermis to the dermis through adhesion at the dermo-epidermal basement membrane zone. Thus, different forms of EB have been highly instructive in providing information on the physiological functions of these proteins as integral components of the supramolecular adhesion complexes. In addition, precise information of the underlying genes and distinct mutations in families with EB has been helpful in subclassification of the disease with prognostic implications, as well as for prenatal testing and preimplantation genetic diagnosis. Furthermore, knowledge of the types of mutations is a prerequisite for application of allele-specific treatment approaches that have been recently developed, including read-through of premature termination codon mutations and chaperone-facilitated intracellular transport of conformationally altered proteins to proper physiologic subcellular location. Collectively, EB serves as a paradigm of heritable skin diseases in which significant progress has been made in identifying the underlying genetic bases and associated aberrant pathways leading from mutations to the phenotype, thus allowing application of precision medicine for this, currently intractable group of diseases.

Next-generation sequencing for mutation detection in heritable skin diseases: the paradigm of pseudoxanthoma elasticum.

Next-generation sequencing applied either to the entire genome or to a subset, such as a whole exome, has revolutionized the search for pathogenic mutations in heritable diseases, including genodermatoses. In this issue, Hosen et al. applied whole-exome sequencing to identify potential pathogenic mutations in four candidate genes associated with pseudoxanthoma elasticum, the prototype of ectopic mineralization disorders. The study highlights the advantages of this approach over traditional Sanger sequencing, including expedience and cost, but it also illustrates some of the challenges encountered in implementing this rapidly evolving technology.

The effects of bisphosphonates on ectopic soft tissue mineralization caused by mutations in the ABCC6 gene.

Pseudoxanthoma elasticum (PXE) and generalized arterial calcification of infancy (GACI) are heritable ectopic mineralization disorders. Most cases of PXE and many cases of GACI harbor mutations in the ABCC6 gene. There is no effective treatment for these disorders. We explored the potential efficacy of bisphosphonates to prevent ectopic calcification caused by ABCC6 mutations by feeding Abcc6(-/-) mice with diet containing etidronate disodium (ETD) or alendronate sodium trihydrate (AST) in quantities corresponding to 1x, 5x, or 12x of the doses used to treat osteoporosis in humans. The mice were placed on diet at 4 weeks of age, and the degree of mineralization was assessed at 12 weeks by quantitation of the calcium deposits in the dermal sheath of vibrissae, a progressive biomarker of the mineralization, by computerized morphometry of histopathologic sections and by direct chemical assay of calcium. We found that ETD, but not AST, at the 12x dosage, significantly reduced mineralization, suggesting that selected bisphosphonates may be helpful for prevention of mineral deposits in PXE and GACI caused by mutations in the ABCC6 gene, when combined with careful monitoring of efficacy and potential side-effects.

Expression of transforming growth factor-ß after different non-invasive facial rejuvenation modalities.

BACKGROUND: Transforming growth factor-ß (TGF-ß) is a major regulator of the synthesis of extracellular matrix (ECM) proteins in human skin as it stimulates fibroblast proliferation and collagen production. Perturbed TGF-ß expression may play a key role in the pathogenesis of skin aging. OBJECTIVES: This study was conducted to objectively evaluate the effects of different modalities of non-invasive facial rejuvenation on TGF-ß expression and to correlate its level with that of newly synthesized collagen. METHODS: A total of 36 patients with Fitzpatrick skin types III and IV were divided into six groups. Each group of six patients was subjected to a different non-invasive modality for the treatment of skin aging, including radiofrequency (RF), Nd:YAG 1320-nm laser and Er:YAG 2940-nm laser mini-peels, intense pulsed light (IPL), mesotherapy injection, and electro-optical synergy (ELOS). Skin biopsies were obtained before treatment, at the end of treatment, and at three months post-treatment. In addition, biopsies were obtained from 30 control subjects. Levels of TGF-ß were quantitatively evaluated using computerized image analysis of immunostained sections. RESULTS: The expression of TGF-ß was statistically significantly increased (P < 0.05) at the end of Nd:YAG 1320-nm and Er:YAG 2940-nm mini-peel treatments compared with baseline levels, and at three months post-treatment with RF and ELOS compared with pretreatment and end-of-treatment levels. However, no significant differences (P > 0.05) were observed in TGF-ß level in response to IPL or mesotherapy treatments in comparison with baseline. The level of TGF-ß was positively correlated (P < 0.05) to that of newly synthesized collagen at the end of Nd:YAG 1320-nm laser and Er:YAG 2940-nm laser mini-peels, as well as at three months after RF and ELOS treatments. CONCLUSIONS: Radiofrequency, ELOS, and Nd:YAG 1320-nm laser and Er:YAG 2940-nm laser mini-peels resulted in an increase in TGF-ß expression, which may mediate the effects of these modalities in enhancing dermal collagen expression through the activation of fibroblasts and thereby reverse the photoaging of skin.

Genetic modulation of nephrocalcinosis in mouse models of ectopic mineralization: the Abcc6(tm1Jfk) and Enpp1(asj) mutant mice.

Ectopic mineralization of renal tissues in nephrocalcinosis is a complex, multifactorial process. The purpose of this study was to examine the role of genetic modulation and the role of diet in nephrocalcinosis using two established mouse models of ectopic mineralization, Abcc6(tm1Jfk) and Enpp1(asj) mice, which serve as models for pseudoxanthoma elasticum and generalized arterial calcification of infancy, two heritable disorders, respectively. These mutant mice, when on standard rodent diet, develop nephrocalcinosis only at a very late age. In contrast, when placed on an 'acceleration diet' composed of increased phosphate and reduced magnesium content, they showed extensive mineralization of the kidneys affecting primarily the medullary tubules as well as arcuate and renal arteries, as examined by histopathology and quantitated by chemical assay for calcium. Mineralization could also be detected noninvasively by micro computed tomography. Whereas the heterozygous mice did not develop nephrocalcinosis, compound heterozygous mice carrying both mutant alleles, Abcc6(tm1Jfk/+) and Enpp1(+/asj), developed ectopic mineralization similar to that noted in homozygous mice for either gene, indicating that deletion of one Abcc6 allele along with Enpp1 haploinsufficiency resulted in renal mineralization. Thus, synergistic genetic defects in the complex mineralization/antimineralization network can profoundly modulate the degree of ectopic mineralization in nephrocalcinosis.

Rate of change of carotid intima-media thickness with magnesium administration in Abcc6⁻/⁻ mice.

Pseudoxanthoma elasticum (PXE), caused by mutations in the ABCC6 gene, demonstrates progressive build-up of calcium phosphate and proteoglycans in the skin, eye, and arteries, and is associated to myocardial infarctions, stroke, blindness, and elevated carotid intima-media thickness (CIMT). Although CIMT reduction with magnesium (Mg) has been documented in a mouse model for PXE (Abcc6(-/-) ), it is not clear if Mg is effective in humans with PXE to reduce CIMT. To examine this, we calculated the rate of change of CIMT (washout) in 15- and 12-month-old Abcc6(-/-) mice fed standard rodent diet with or without Mg supplementation for 2 months. Using means in untreated 15- and 12-month-old Abcc6(-/-) mice (145 and 120 µm, respectively), the rate of change was 8.3 µm/month. Using means in treated 15- and 12-month-old Abcc6(-/-) mice (118 and 104.6 µm, respectively), the rate of change was 4.5 µm. Compared to normal progression of CIMT in humans without PXE, PXE has advanced atherosclerosis and possibly a higher CIMT rate of change. This experiment may portend, at least in PXE, the rationale for a 1-year oral Mg CIMT clinical trial and may be useful for application in other progressive mineralizing disorders like atherosclerosis.

Mutant Enpp1asj mice as a model for generalized arterial calcification of infancy.

Generalized arterial calcification of infancy (GACI), an autosomal recessive disorder, is characterized by early mineralization of blood vessels, often diagnosed by prenatal ultrasound and usually resulting in demise during the first year of life. It is caused in most cases by mutations in the ENPP1 gene, encoding an enzyme that hydrolyzes ATP to AMP and inorganic pyrophosphate, the latter being a powerful anti-mineralization factor. Recently, a novel mouse phenotype was recognized as a result of ENU mutagenesis - those mice developed stiffening of the joints, hence the mutant mouse was named 'ages with stiffened joints' (asj). These mice harbor a missense mutation, p.V246D, in the Enpp1 gene. Here we demonstrate that the mutant ENPP1 protein is largely absent in the liver of asj mice, and the lack of enzymatic activity results in reduced inorganic pyrophosphate (PPi) levels in the plasma, accompanied by extensive mineralization of a number of tissues, including arterial blood vessels. The progress of mineralization is highly dependent on the mineral composition of the diet, with significant shortening of the lifespan on a diet enriched in phosphorus and low in magnesium. These results suggest that the asj mouse can serve as an animal model for GACI.

Premature termination codon read-through in the ABCC6 gene: potential treatment for pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is an autosomal recessive disorder manifesting with ectopic connective tissue mineralization, caused by mutations in the ABCC6 gene, with ~35% of all mutations being premature termination mutations. In this study, we investigated the therapeutic potential of the nonsense codon read-through-inducing drug, PTC124, in treating PXE. The ability of this drug to facilitate read-through of nonsense mutations was examined in HEK293 cells transfected with human ABCC6 expression constructs harboring seven different PXE-associated nonsense mutations, and was evaluated by immunofluorescence and In-Cell ELISA. Our data demonstrated that PTC124 did not exhibit cytotoxicity in concentrations up to 20 µg ml(-1), and the facilitated read-through varied not only with dose but also with sequence context. Considering the redundancy of the genetic code, it was postulated that in case of the most common recurrent nonsense mutation, p.R1141X, the read-through may result in substitution of the arginine 1,141 by glycine, tryptophan, or cysteine. Their potential pathogenicity was tested in a recently developed zebrafish messenger RNA (mRNA) rescue assay, and demonstrated that all three mRNA transcripts were able to rescue abcc6a morpholino-induced phenotype of zebrafish. Thus, our results suggest that read-through of nonsense mutations in ABCC6 by PTC124 may have potential for pharmacologic treatment of PXE.

Warfarin accelerates ectopic mineralization in Abcc6(-/-) mice: clinical relevance to pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a multisystem ectopic mineralization disorder caused by mutations in the ABCC6 gene. Warfarin, a commonly used anticoagulant, is associated with increased mineralization of the arterial blood vessels and cardiac valves. We hypothesized that warfarin may accelerate ectopic tissue mineralization in PXE, with clinical consequences. To test this hypothesis, we developed a model in which Abcc6(-/-) mice, which recapitulate features of PXE, were fed a diet supplemented with warfarin and vitamin K1. Warfarin action was confirmed by significantly increased serum levels of oxidized vitamin K. For mice placed on a warfarin-containing diet, quantitative chemical and morphometric analyses revealed massive accumulation of mineral deposits in a number of tissues. Mice fed a warfarin-containing diet were also shown to have abundant uncarboxylated form of matrix Gla protein, which allowed progressive tissue mineralization to ensue. To explore the clinical relevance of these findings, 1747 patients with PXE from the approximately 4000 patients in the PXE International database were surveyed about the use of warfarin. Of the 539 respondents, 2.6% reported past or present use of warfarin. Based on the prevalence of PXE (approximately 1:50,000), thousands of patients with PXE worldwide may be at risk for worsening of PXE as a result of warfarin therapy.

Efficacy of mesotherapy in facial rejuvenation: a histological and immunohistochemical evaluation.

BACKGROUND: Mesotherapy, commonly known as "biorejuvenation" or "biorevitalization", is a technique used to rejuvenate the skin by means of a transdermal injection of a multivitamin solution and natural plant extracts that are thought to improve the signs of skin aging. OBJECTIVES: This prospective study aimed to evaluate the clinical effect of mesotherapy applied to periorbital wrinkles and to quantitatively evaluate histological changes in the skin occurring in response to the same treatment. METHODS: Six volunteers with Fitzpatrick skin types III or IV and Glogau class I-III wrinkles were subjected to a three-month course of mesotherapy injections in the periocular area (six sessions administered at two-week intervals). Standard photographs and skin biopsies were obtained from the treatment area at baseline, at the end of treatment, and at three months post-treatment. Quantitative evaluation of collagen types I, III, and VII, newly synthesized collagen, total elastin, and tropoelastin was performed using a computerized morphometric analysis. RESULTS: The clinical evaluation of volunteers at baseline, end of treatment, and three months post-treatment revealed no significant differences. Histological and immunostaining analysis of collagen types I, III, and VII, newly synthesized collagen, total elastin, and tropoelastin showed no statistically significant changes (P > 0.05) after mesotherapy injection. CONCLUSIONS: The present study indicates that mesotherapy for skin rejuvenation does not result in statistically significant histological changes or clinical improvement.

Magnesium reduces carotid intima-media thickness in a mouse model of pseudoxanthoma elasticum: a novel treatment biomarker.

Pseudoxanthoma elasticum (PXE), which demonstrates progressive build-up of calcium phosphate and proteoglycan deposits in skin, eye, and arteries, has been associated with myocardial infarctions, stroke, and blindness. In a mouse model of PXE, a magnesium-enriched diet prevents mineralization of the vibrissae capsule, an early biomarker for PXE. However, biomarkers for therapeutic responses in PXE have not been identified in humans. Because PXE patients have an increased carotid intima-media thickness (CIMT), a risk factor for cardiovascular disease and stroke, we analyzed the feasibility of CIMT as a treatment endpoint before and after magnesium supplementation in a mouse model of PXE (Abcc6(-/-) ). CIMT was measured in 1-year-old Abcc6(-/-) and Abcc6(+/+) mice fed either standard rodent diet with or without magnesium oxide supplementation for 2 months. Baseline CIMT in Abcc6(-/-) versus Abcc6(+/+) mice was increased (p value = 0.009), whereas CIMT in magnesium-treated versus untreated Abcc6(-/-) mice was reduced (p value = 0.024). CIMT is a novel treatment endpoint in this mouse model and may serve as a predictive biomarker of therapeutic response in PXE patients. In that context, magnesium oxide significantly reduced CIMT in PXE mice, and may be useful for disease prevention in PXE patients.

Intense pulsed light photorejuvenation: a histological and immunohistochemical evaluation.

BACKGROUND: The use of intense pulsed light (IPL) for facial rejuvenation had been the topic of many studies. However, few of them discussed quantitative changes in extracellular matrix proteins after IPL therapy. OBJECTIVE: To objectively quantify the histological changes in extracellular matrix proteins after IPL treatment for facial wrinkles. METHODS: Biopsy specimens were obtained from the periocular area of six volunteers of Fitzpatrick skin type III-IV and Glogau's class I-III wrinkles. They were subjected to three months of IPL treatment (six sessions at two-week intervals). Using histological and immunostaining analysis coupled with computerized morphometric analysis, quantitative evaluation of collagen types I, III and VII, newly synthesized collagen, total elastin and tropoelastin was performed for skin biopsies at baseline, end of treatment, and three months post-treatment. RESULTS: Clinical assessment of volunteers did not show clinically noticeable improvement in facial wrinkles after IPL treatment. Furthermore, quantitative evaluation of extracellular matrix proteins showed no statistically significant changes (P>0.05) in response to IPL treatment CONCLUSION: Although 50 percent of volunteers showed mild improvement in skin texture at the end of IPL treatment, none of them reported improvement in skin tightening or wrinkles. No statistically significant histological changes were observed three months post IPL treatment.

Effects of the Nd:YAG 1320-nm laser on skin rejuvenation: clinical and histological correlations.

The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser is a popular non-ablative treatment used for skin rejuvenation. The purpose of this prospective study was to evaluate the clinical effects, coupled with a quantitative assessment, of the histological changes in response to Nd:YAG 1320-nm laser treatment of periocular wrinkles. Six volunteers with Fitzpatrick skin types III and IV and Glogau class I-II wrinkles were subjected to 3 months of Nd:YAG 1320-nm treatment in the periocular area (six sessions at 2-week intervals). Volunteers were photographed, and skin biopsies were obtained at baseline as well as 3 and 6 months after the start of treatments. Quantitative evaluation of total elastin, newly synthesized tropoelastin, collagen types I, III and VII, and newly synthesized collagen was performed using a computerized morphometric analysis. A noticeable clinical and histological improvement was observed after Nd:YAG 1320-nm treatment. Collagen types I, III and VII, as well as newly synthesized collagen, together with tropoelastin showed a statistically significant increase in response to treatment, while the mean level of total elastin was significantly decreased after treatment. Our data suggest that Nd:YAG 1320 nm is an effective treatment for skin rejuvenation as it stimulates the repair processes, and reverses the clinical, as well as the histopathological, signs of skin aging.