Paraoxonase-2 shRNA-mediated gene silencing suppresses proliferation and migration, while promotes chemosensitivity in clear cell renal cell carcinoma cell lines.

Clear cell renal cell carcinoma (ccRCC) represents the most common subtype of renal tumor. Despite recent advances in identifying novel target molecules, the prognosis of patients with ccRCC continues to be poor, mainly due to the lack of sensitivity to chemo- and radiotherapy and because of one-third of renal cell carcinoma patients displays metastatic disease at diagnosis. Thus, identifying new molecules for early detection and for developing effective targeted therapies is mandatory. In this work, we focused on paraoxonase-2 (PON2), an intracellular membrane-bound enzyme ubiquitously expressed in human tissues, whose upregulation has been reported in a variety of malignancies, thus suggesting its possible role in cancer cell survival and proliferation. To investigate PON2 involvement in tumor cell metabolism, human ccRCC cell lines were transfected with plasmid vectors coding short harpin RNAs targeting PON2 transcript and the impact of PON2 silencing on cell viability, migration, and response to chemotherapeutic treatment was then explored. Our results showed that PON2 downregulation was able to trigger a decrease in proliferation and migration of ccRCC cells, as well as an enhancement of cell sensitivity to chemotherapy. Thus, taken together, data reported in this study suggest that the enzyme may represent an interesting therapeutic target for ccRCC.

Role Played by Paraoxonase-2 Enzyme in Cell Viability, Proliferation and Sensitivity to Chemotherapy of Oral Squamous Cell Carcinoma Cell Lines.

Oral squamous cell carcinoma represents the most aggressive and frequent form of head and neck cancer. Due to drug resistance, the 5-year survival rate of patients with advanced disease is less than 50%. In order to identify molecular targets for effective oral cancer treatment, we focused on paraoxonase-2 enzyme. Indeed, based on data previously obtained from preliminary immunohistochemistry and Western blot analyses performed on tissue specimens, the enzyme was found to be upregulated in tumor compared with normal oral mucosa. Therefore, paraoxonase-2 gene silencing was achieved in HSC-3 and HOC621 oral cancer cell lines, and the effect on cell proliferation, viability, apoptosis induction and sensitivity to cisplatin and 5-fluorouracil treatment was evaluated. Fourier Transform InfraRed Microspectroscopy analyzed alterations of cellular macromolecules upon treatment. Enzyme level and cell proliferation were also determined in cisplatin-resistant clones obtained from HOC621 cell line, as well as in parental cells. Reported data showed that paraoxonase-2 knockdown led to a reduction of cell proliferation and viability, as well as to an enhancement of sensitivity to cisplatin, together with the activation of apoptosis pathway. Spectroscopical data demonstrated that, under treatment with cisplatin, oxidative damage exerted on lipids and proteins was markedly more evident in cells down-regulating paraoxonase-2 compared to controls. Interestingly, enzyme expression, as well as cell proliferation were significantly higher in cisplatin-resistant compared with control HOC621 cells. Taken together these results seem to candidate the enzyme as a promising target for molecular treatment of this neoplasm.

Paraoxonase-2: A potential biomarker for skin cancer aggressiveness.

BACKGROUND: Cutaneous neoplasms include melanoma and non-melanoma skin cancers (NMSCs). Among NMSCs, basal cell carcinoma (BCC) represents the most common lesion. On the contrary, although accounting for less than 5% of all skin cancers, melanoma is responsible for most of cutaneous malignancy-related deaths. Paraoxonase-2 (PON2) is an intracellular enzyme exerting a protective role against production of reactive oxygen species within mitochondrial respiratory chain. Recently, a growing attention has been focused on exploring the role of PON2 in cancer. The aim of this study was to investigate the diagnostic and prognostic role of PON2 in skin neoplasms. MATERIALS AND METHODS: 36 cases of BCC, distinguished between nodular and infiltrative lesions, as well as 29 melanoma samples were analysed by immunohistochemistry to evaluate PON2 protein expression. Subsequent statistical analyses were carried out to explore the existence of correlations between intratumour enzyme levels and clinicopathological features. RESULTS: Results obtained showed PON2 overexpression in BCCs compared with controls. In particular, distinguishing between less and more aggressive tumour forms, we found no significant differences in enzyme levels between nodular BCCs and controls. Conversely, PON2 expression was significantly higher in infiltrative BCCs compared with controls. Moreover, the enzyme was strongly upregulated in melanoma samples with respect to controls. Interestingly, PON2 levels were positively correlated with Breslow thickness, Clark level, regression, mitoses, lymph node metastases, primary tumour (pT) parameter and pathological stage. CONCLUSIONS: Reported findings seem to suggest that PON2 expression levels could be positively related with tumour aggressiveness of both BCC and melanoma.

Cancer stem cell enrichment is associated with enhancement of nicotinamide N-methyltransferase expression.

The cancer stem cell theory states that a subset of tumor cells, termed cancer stem cells (CSCs), has the ability to self-renew and differentiate within the tumors. According to this theory, CSCs would be mainly responsible for tumor initiation, progression, resistance to therapy, recurrence, and metastasis. In this study, a culture system was setup to enrich CSCs from bladder cancer (T24), lung cancer (A549), colorectal cancer (CaCo-2), and osteosarcoma (MG63) cell lines, through sphere formation. Magnetic-activated cell sorting was also used to further increase CSC enrichment. Subsequently, molecular characterization of CSC-enriched cell populations and parental cells was carried out, by exploring the expression levels of stem markers and the enzyme nicotinamide N-methyltransferase (NNMT). Results obtained showed a significant upregulation of stem cell markers in CSC-enriched populations, obtained upon sphere formation, compared with parental counterparts. Moreover, NNMT expression levels were markedly increased in samples enriched with CSCs with respect to control cells. Considering the fundamental role played by CSCs in carcinogenesis, reported data strengthen the hypothesis that sustains a pivotal role of NNMT in cancer growth and metastasis. In addition, these findings could represent an important achievement for the development of new and effective anticancer therapies, based on CSC-associated targets.

Nitric oxide synthase and VEGF expression in full-term placentas of obese women.

An adequate placental vascularization allows the proper development of the fetus and it is crucial for the gestational success. A number of factors regulate angiogenesis, including vascular endothelial growth factor (VEGF), which induces the synthesis of nitric oxide (NO), a potent vasodilator produced by three different nitric oxide synthase (NOS) isoforms. NO is essential to maintain a low vascular resistance in the fetoplacental circulation, although at high concentrations, it may combine with excess superoxide to produce peroxynitrite, which reacts with proteins giving rise to nitrotyrosine. Since obesity, whose incidence is increasing worldwide, is characterized by a low-grade inflammatory state and increased levels of oxidative and nitrative stress, both affecting placental function, our aim was to evaluate the expression of VEGF, eNOS, and iNOS in full-term placentas obtained from normal weight and pre-pregnancy obese women by means of immunohistochemistry and real-time PCR. Moreover, we assessed the NO levels and the nitrotyrosine immunoexpression in the same sample groups. Our results show a significantly higher immunohistochemical expression of VEGF and eNOS in the endothelium of placentas from obese women than in controls, whereas the immunoexpression of iNOS was comparable in the two groups. These data agree with those of the gene expression analysis, thus suggesting the possible existence of a compensatory mechanism for changes in placental blood flow associated with obesity. As concerns nitrotyrosine and NO levels, we observed a significant increase in placental tissue from obese women which may contribute to the development of metabolic and cardiovascular diseases both in the mother and the offspring.

Nicotinamide N-methyltransferase in nonmelanoma skin cancers.

BACKGROUND: Squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) represent the most common forms of nonmelanoma skin cancers (NMSCs). Although successful treatment of these neoplasms is based on surgical excision, an increasing number of BCCs relapses and many SCCs display high rates of recurrence and metastasis. Nicotinamide N-methyltransferase (NNMT) is a cytosolic enzyme, which was found to be upregulated in different solid tumours. However, there are no data regarding enzyme expression in NMSCs. The aim of this study was therefore to evaluate the potential involvement of NNMT in BCCs and SCCs. MATERIALS AND METHODS: Immunohistochemical analyses were carried out on 40 BCC cases and 39 SCC cases, to evaluate enzyme expression in tumour and surrounding healthy margins. Moreover, the relationship between NNMT intratumour levels and clinico-pathological parameters were explored. RESULTS: Nicotinamide N-methyltransferase was found to be overexpressed in BCCs compared with control tissues, while a significant enzyme downregulation was detected in SCCs with respect to corresponding healthy margins. In addition, NNMT levels were negatively related to aggressiveness of both BCCs (distinguishing between infiltrative and nodular tumours) and SCCs (considering head and neck forms and tumours of the extremities and trunk). CONCLUSIONS: These evidences seem to demonstrate that the different NNMT dysregulation detected in BCC and SCC may be the result of important biological traits distinctively characterizing these two forms within NMSCs. In addition, enzyme levels seem to be inversely correlated with tumour aggressiveness, thus suggesting the potential suitability of the enzyme as a prognostic biomarker for both neoplasms.

Interleukin-1ß, cyclooxygenase-2, and hypoxia-inducible factor-1α in asthenozoospermia.

Impaired male fertility may have a variety of causes, among which asthenozoospermia. In its etiology, several bioactive substances, such as cytokines may be involved. In this context, our aim was to evaluate the expression of interleukin-1ß, cyclooxygenase-2, and hypoxia-inducible factor-1α, in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients. We evaluated twenty-eight infertile patients affected by idiopathic asthenozoospermia and twenty-three normospermic fertile donors, age-matched. Sperm parameters were evaluated; immunohistochemical analysis and enzyme-linked immunosorbent assay were then performed in isolated spermatozoa. Spermatozoa from the asthenozoospermic group presented an increased expression of IL-1ß, COX-2, and HIF-1α compared with the normospermic fertile subjects. Our results can lead us to speculate that the increased expression of these substances may influence sperm motility. Nevertheless, further studies are needed in order to assess whether these bioactive mediators have a potential relevance as targets in future therapeutic strategies for the treatment of male infertility.

Curcumin and its Analogues in Oral Squamous Cell Carcinoma: State-of-the-art and Therapeutic Potential.

Oral Squamous Cell Carcinoma (OSCC) is the most common cancer arising from squamous epithelium in the oral cavity and is characterized by high aggressiveness and metastatic potential, which together with a late diagnosis results in a 5-year survival rate of only 50% of patients. The therapeutic options for OSCC management are limited and largely influenced by the cancer stage. While radical surgery can be curative in early stage of disease, most cases require adjuvant therapies, including chemotherapy and radiotherapy which, however, often achieve poor curative rates and are associated with important negative effects. Therefore, there is an urgent need to discover new alternative treatment strategies to improve patients' outcomes. Several medicinal herbs are being studied for their preventive or therapeutic effect in several diseases, including cancer. In particular, the Indian spice curcumin, largely used in oriental countries, has been studied as a chemopreventive or adjuvant agent for different malignancies. Indeed, curcumin is characterized by important biological properties, including antioxidant, anti-inflammatory, and anticancer effects, which could also be exploited in OSCC. However, due to its limited bioavailability and poor aqueous solubility, this review is focused on studies designing new synthetic analogues and developing novel types of curcumin delivery systems to improve its pharmacokinetic and biological properties. Thus, this review analyses the potential therapeutic role of curcumin in OSCC by providing an overview of current in vitro and in vivo studies demonstrating the beneficial effects of curcumin and its analogues in OSCC.

Contribution of the Paraoxonase-2 Enzyme to Cancer Cell Metabolism and Phenotypes.

Paraoxonase-2 (PON2) is a ubiquitously expressed intracellular protein that is localized in the perinuclear region, the endoplasmic reticulum (ER), and mitochondria, and is also associated with the plasma membrane. PON2 functions as an antioxidant enzyme by reducing the levels of reactive oxygen species (ROS) in the mitochondria and ER through different mechanisms, thus having an anti-apoptotic effect and preventing the formation of atherosclerotic lesions. While the antiatherogenic role played by this enzyme has been extensively explored within endothelial cells in association with vascular disorders, in the last decade, great efforts have been made to clarify its potential involvement in both blood and solid tumors, where PON2 was reported to be overexpressed. This review aims to deeply and carefully examine the contribution of this enzyme to different aspects of tumor cells by promoting the initiation, progression, and spread of neoplasms.

In Vitro Study of the Proliferation of MG63 Cells Cultured on Five Different Titanium Surfaces.

The use of dental implants for prosthetic rehabilitation in dentistry is based on the concept of osteointegration. This concept enables the clinical stability of the implants and a total absence of inflammatory tissue between the implant surface and the bone tissue. For this reason, it is essential to understand the role of the titanium surface in promoting and maintaining or not maintaining contact between the bone matrix and the surface of the titanium implant. MATERIALS AND METHODS: Five types of titanium discs placed in contact with osteoblast cultures of osteosarcomas were studied. The materials had different roughness. Scanning electron microscopy (SEM) photos were taken before the in vitro culture to analyze the surfaces, and at the end of the culturing time, the different gene expressions of a broad pattern of proteins were evaluated to analyze the osteoblast response, as indicated in the scientific literature. RESULTS: It was demonstrated that the responses of the osteoblasts were different in the five cultures in contact with the five titanium discs with different surfaces; in particular, the response in the production of some proteins was statistically significant. DISCUSSION: The key role of titanium surfaces underlines how it is still possible to carry out increasingly accurate and targeted studies in the search for new surfaces capable of stimulating a better osteoblastic response and the long-term maintenance of osteointegration.

Pro-inflammatory cytokine alterations in recent onset anorexia nervosa adolescent female patients before and after 6 months of integrated therapy: A case-control study.

Anorexia nervosa (AN) is a complex disorder affecting mainly, but not only, teenagers. Researchers agree that AN is deeply associated with a pro-inflammatory state following an impaired immune system, resulting from altered levels of cytokines such as IL-1ß and TNF-α, also impacted by the frequent depressive states. Thus, this case-control study aimed to evaluate the relationship between patients suffering from AN undergoing specialized eating disorder treatment for AN and pro-inflammatory cytokines. To reach our purpose, we assessed eating-related psychopathology and depressive symptoms and measured serum concentration of pro-inflammatory cytokines IL-1ß, IL-6, IL-8, and TNF-α before and after 6 months of integrated therapy (which included psychopharmacotherapy, psychotherapy, and nutritional treatment), to define whether selected pro-inflammatory cytokines could be considered a pathophysiological marker of the disorder. A sample of 16 young female patients with early diagnosis of AN, and without any previous treatment, and 22 healthy controls matched by age, sex, and socioeconomic status were enrolled. After 6 months of integrated therapy, a significant decrease of all selected pro-inflammatory cytokines was detected. In addition, an improvement in the anxiety-depressant aspects was also noted. In conclusion, the results obtained suggest that pro-inflammatory cytokines are indeed related to the pathophysiology of AN. However, further investigations, involving larger samples of patients with distinct subtypes of AN, are essential to confirm the current findings.

Knockdown of nicotinamide N-methyltransferase suppresses proliferation, migration, and chemoresistance of Merkel cell carcinoma cells in vitro.

Merkel cell carcinoma (MCC) is an aggressive skin cancer, with a propensity for early metastasis. Therefore, early diagnosis and the identification of novel targets become fundamental. The enzyme nicotinamide N-methyltransferase (NNMT) catalyzes the reaction of N-methylation of nicotinamide and other analogous compounds. Although NNMT overexpression was reported in many malignancies, the significance of its dysregulation in cancer cell phenotype was partly clarified. Several works demonstrated that NNMT promotes cancer cell proliferation, migration, and chemoresistance. In this study, we investigated the possible involvement of this enzyme in MCC. Preliminary immunohistochemical analyses were performed to evaluate NNMT expression in MCC tissue specimens. To explore the enzyme function in tumor cell metabolism, MCC cell lines have been transfected with plasmids encoding for short hairpin RNAs (shRNAs) targeting NNMT mRNA. Preliminary immunohistochemical analyses showed elevated NNMT expression in MCC tissue specimens. The effect of enzyme downregulation on cell proliferation, migration, and chemosensitivity was then evaluated through MTT, trypan blue, and wound healing assays. Data obtained clearly demonstrated that NNMT knockdown is associated with a decrease of cell proliferation, viability, and migration, as well as with enhanced sensitivity to treatment with chemotherapeutic drugs. Taken together, these results suggest that NNMT could represent an interesting MCC biomarker and a promising target for targeted anti-cancer therapy.

Recent Advances in the Management of Clear Cell Renal Cell Carcinoma: Novel Biomarkers and Targeted Therapies.

Renal cell carcinoma (RCC) belongs to a heterogenous cancer group arising from renal tubular epithelial cells. Among RCC subtypes, clear cell renal cell carcinoma (ccRCC) is the most common variant, characterized by high aggressiveness, invasiveness and metastatic potential, features that lead to poor prognosis and high mortality rate. In addition, diagnosis of kidney cancer is incidental in the majority of cases, and this results in a late diagnosis, when the stage of the disease is advanced and the tumor has already metastasized. Furthermore, ccRCC treatment is complicated by its strong resistance to chemo- and radiotherapy. Therefore, there is active ongoing research focused on identifying novel biomarkers which could be useful for assessing a better prognosis, as well as new molecules which could be used for targeted therapy. In this light, several novel targeted therapies have been shown to be effective in prolonging the overall survival of ccRCC patients. Thus, the aim of this review is to analyze the actual state-of-the-art on ccRCC diagnosis, prognosis and therapeutic options, while also reporting the recent advances in novel biomarker discoveries, which could be exploited for a better prognosis or for targeted therapy.

The Double-Edged Sword of Oxidative Stress in Skin Damage and Melanoma: From Physiopathology to Therapeutical Approaches.

The skin is constantly exposed to exogenous and endogenous sources of reactive oxygen species (ROS). An adequate balance between ROS levels and antioxidant defenses is necessary for the optimal cell and tissue functions, especially for the skin, since it must face additional ROS sources that do not affect other tissues, including UV radiation. Melanocytes are more exposed to oxidative stress than other cells, also due to the melanin production process, which itself contributes to generating ROS. There is an increasing amount of evidence that oxidative stress may play a role in many skin diseases, including melanoma, being the primary cause or being a cofactor that aggravates the primary condition. Indeed, oxidative stress is emerging as another major force involved in all the phases of melanoma development, not only in the arising of the malignancy but also in the progression toward the metastatic phenotype. Furthermore, oxidative stress seems to play a role also in chemoresistance and thus has become a target for therapy. In this review, we discuss the existing knowledge on oxidative stress in the skin, examining sources and defenses, giving particular consideration to melanocytes. Therefore, we focus on the significance of oxidative stress in melanoma, thus analyzing the possibility to exploit the induction of oxidative stress as a therapeutic strategy to improve the effectiveness of therapeutic management of melanoma.

VEGF and nitric oxide synthase immunoexpression in Down's syndrome amniotic fluid stem cells.

BACKGROUND: It has been previously observed that the amniotic fluid obtained from Down's syndrome (DS) pregnancies showed lower levels of vascular endothelial growth factor (VEGF) and higher levels of nitric oxide (NO) with respect to the controls, suggesting the presence of an imbalance between placental vascularization and altered endothelial function. The aim of our study was to evaluate the immunohistochemical expression and localization of VEGF and nitric oxide synthase (NOS) isoforms in cultured amniotic fluid mesenchymal stem cells (AF-MSCs) isolated from normal euploid pregnancies and pregnancies complicated by trisomy 21. In addition, we measured the VEGF and NO content in cell culture supernatants to analyse their production by AF-MSCs. MATERIALS AND METHODS: AF-MSCs were obtained from women with foetal DS and controls matched for age and gestation, and expanded in culture. The cells were then evaluated for the immunohistochemical expression of VEGF and NOS isoforms, as well as for the release of VEGF and NO. RESULTS: Our analyses showed that both the VEGF expression and production were significantly lower in DS-AF-MSCs with respect to the controls. As regards NOS, immunohistochemical expression of eNOS was significantly reduced in DS-AF-MSCs, whereas the nNOS and iNOS were similarly immunoexpressed in both groups of cells. Moreover, we observed that the NO content was significantly higher in medium derived by DS-AF-MSCs. CONCLUSIONS: Our study shows, for the first time, the differences between AF-MSCs isolated from control and trisomy 21 pregnancies and suggest an involvement of NO and VEGF in the physiopathological mechanisms associated with DS pregnancy.

Beyond Nicotinamide Metabolism: Potential Role of Nicotinamide N-Methyltransferase as a Biomarker in Skin Cancers.

Skin cancers (SC) collectively represent the most common type of malignancy in white populations. SC includes two main forms: malignant melanoma and non-melanoma skin cancer (NMSC). NMSC includes different subtypes, namely, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Merkel cell carcinoma (MCC), and keratoacanthoma (KA), together with the two pre-neoplastic conditions Bowen disease (BD) and actinic keratosis (AK). Both malignant melanoma and NMSC are showing an increasing incidence rate worldwide, thus representing an important challenge for health care systems, also because, with some exceptions, SC are generally characterized by an aggressive behavior and are often diagnosed late. Thus, identifying new biomarkers suitable for diagnosis, as well as for prognosis and targeted therapy is mandatory. Nicotinamide N-methyltransferase (NNMT) is an enzyme that is emerging as a crucial player in the progression of several malignancies, while its substrate, nicotinamide, is known to exert chemopreventive effects. Since there is increasing evidence regarding the involvement of this enzyme in the malignant behavior of SC, the current review aims to summarize the state of the art as concerns NNMT role in SC and to support future studies focused on exploring the diagnostic and prognostic potential of NNMT in skin malignancies and its suitability for targeted therapy.

Nicotinamide N-Methyltransferase in Head and Neck Tumors: A Comprehensive Review.

The head and neck tumors (HNT) are a heterogeneous group of diseases ranging from benign to malignant lesions, with distinctive molecular and clinical behaviors. Several studies have highlighted the presence of an altered metabolic phenotype in HNT, such as the upregulation of nicotinamide N-methyltransferase (NNMT). However, its biological effects have not been completely disclosed and the role of NNMT in cancer cell metabolism remains unclear. Therefore, this comprehensive review aims to evaluate the available literature regarding the biological, diagnostic, and prognostic role of NNMT in HNT. NNMT was shown to be significantly overexpressed in all of the evaluated HNT types. Moreover, its upregulation has been correlated with cancer cell migration and adverse clinical outcomes, such as high-pathological stage, lymph node metastasis, and locoregional recurrences. However, in oral squamous cell carcinoma (OSCC) these associations are still debated, and several studies have failed to demonstrate the prognostic significance of NNMT. The shRNA-mediated gene silencing efficiently suppressed the NNMT gene expression and exhibited a clear inhibitory effect on cell proliferation, promoting the expression of apoptosis-related proteins and modulating the cell cycle. NNMT could represent a new molecular biomarker and a new target of molecular-based therapy, although further studies on larger patient cohorts are needed to explore its biological role in HNT.

Nicotinamide N-methyltransferase gene silencing enhances chemosensitivity of melanoma cell lines.

Melanoma accounts for less than 5% of all cutaneous neoplasms but is responsible for the greater part of skin cancer-related deaths. Therefore, the identification of molecules that could serve as the therapeutic target is urgent. This study focused on the enzyme nicotinamide N-methyltransferase (NNMT). The effect of NNMT knockdown on cell proliferation and migration of A375 melanoma cells was evaluated by MTT and wound healing assays, respectively. Viability of A375 cells downregulating NNMT was also explored under treatment with dacarbazine, a chemotherapeutic drug approved for advanced melanoma treatment. The impact of enzyme knockdown on cell proliferation and chemosensitivity was also investigated in WM-115 melanoma cells. Results obtained demonstrated that NNMT silencing led to a significant reduction of cell proliferation and migration of A375 cells. Moreover, enzyme downregulation was associated with an increase of melanoma cells sensitivity to treatment with dacarbazine. Analogous effects induced by enzyme knockdown on cell proliferation and chemosensitivity were also found in the WM-115 cell line. Our data seem to demonstrate that NNMT could represent a promising molecular target for the effective treatment of this form of skin cancer.

Skin-derived mesenchymal stem cells (S-MSCs) induce endothelial cell activation by paracrine mechanisms.

The mesenchymal stem cells (MSCs) are able to accumulate at the site of tissue damage. For this reason, they must transmigrate across the endothelium. In this study, we focused on skin-derived MSCs (S-MSCs), because the skin represents a useful stem cell source, and we analysed the VEGF released by S-MSCs, because it is known to promote endothelial cell proliferation and vascular permeability. Moreover, we evaluated the influence of S-MSC-conditioned medium on human aortic endothelial cell intracellular calcium concentration ([Ca(2+)](i)) and nitric oxide (NO) production, given their important role in endothelial permeability modulation. Our results suggest that human S-MSCs may interact with the endothelium via paracrine mechanisms, probably leading to an alteration of the endothelial barrier. Consequently, we could hypothesize that a therapeutic approach based on human skin-derived MSCs may have a positive effect on tissue repair.

Anorexia nervosa: a role for L-arginine supplementation in cardiovascular risk factors?

OBJECTIVE: The aim of the present study was to evaluate the effects of a short-term oral L-arginine treatment on platelet NO production, intracellular calcium concentration, iNOS and eNOS expression, in AN patients. METHOD: Forty outpatients belonging to restricting subtype and 40 normal participants age and sex matched were enrolled in the study. RESULTS: NO production was significantly elevated in the platelets from AN patients compared with controls while [Ca(2+)](i) was significantly decreased in patients with respect to controls. Western blot analysis demonstrated that iNOS isoform was more pronounced in the cell lysates from AN patients than controls. After supplementation with L-arginine, both NO production and [Ca(2+)](i) seem to return to control levels, suggesting a probable recovery of their metabolisms. The same was found after western blot analysis of NOS expression. DISCUSSION: The results here proposed can be considered highly indicative of a positive effect of L-arginine supplementation on platelet NO production in AN patients.