17-β-estradiol potentiates the neurotrophic and neuroprotective effects mediated by the dopamine D3/acetylcholine nicotinic receptor heteromer in dopaminergic neurons

Dopaminergic neurons express a heteromer composed of the dopamine D3 receptor and the α4β2 nicotinic acetylcholine receptor, the D3R-nAChR heteromer, activated by both nicotine and dopamine D2 and D3 receptors agonists, such as quinpirole, and crucial for dopaminergic neuron homeostasis. We now report that D3R-nAChR heteromer activity is potentiated by 17-β-estradiol which acts as a positive allosteric modulator by binding a specific domain on the α4 subunit of the nicotinic receptor protomer. In mouse dopaminergic neurons, in fact, 17-β-estradiol significantly increased the ability of nicotine and quinpirole in promoting neuron dendritic remodeling and in protecting neurons against the accumulation of α-synuclein induced by deprivation of glucose, with a mechanism that does not involve the classical estrogen receptors. The potentiation induced by 17-β-estradiol required the D3R-nAChR heteromer since either nicotinic receptor or dopamine D3 receptor antagonists and interfering TAT-peptides, but not the estrogen receptor antagonist fulvestrant, specifically prevented 17-β-estradiol effects. Evidence of estrogens neuroprotection, mainly mediated by genomic mechanisms, have been provided, which is in line with epidemiological data reporting that females are less likely to develop Parkinson's Disease than males. Therefore, potentiation of D3R-nAChR heteromer activity may represent a further mechanism by which 17-β-estradiol reduces dopaminergic neuron vulnerability.

In-vitro Approaches to Investigate the Detrimental Effect of Light on Dopaminergic Neurons

Our recent study revealed that fluorescent lamp light can penetrate deep into the brain of mice and rats leading to the development of typical histological characteristics associated with Parkinson's disease such as the loss of dopamine neurons in the substantia nigra. Monochromatic LED lights were thus used in this work to deepen our knowledge on the effects of the major wavelength peaks of fluorescent light on mouse and human dopaminergic cells. In particular, we exposed immortalized dopaminergic MN9D neuronal cells, primary cultures of mouse mesencephalic dopaminergic cells and human dopaminergic neurons differentiated from induced pluripotent stem cells (hiPSC) to different LED light wavelengths. We found that chronic exposure to LED light reduced overall undifferentiated MN9D cell number, with the most significant effects observed at wavelengths of 485 nm and 610 nm. Moreover, LED light especially at 610 nm was able to negatively impact on the survival of mouse mesencephalic dopaminergic cells and of human dopaminergic neurons derived from hiPSC. Notably, differentiated MN9D dopaminergic cells, which closely resemble mature dopamine neuronal phenotype, acutely exposed for 3 h at 610 nm, showed a clear increase in ROS production and cytotoxicity compared to controls undifferentiated MN9D cells. These increases were even more pronounced by the co-treatment with the oxidative agent H2O2. Collectively, these findings suggest that specific wavelengths, particularly those capable of penetrating deep into the brain, could potentially pose an environmental hazard in relation to Parkinson's disease.

Delay in Cutaneous Squamous Cell Carcinoma Diagnosis Due to Interrupted Services Is Associated with Worse Prognoses and Modified Surgical Approaches

BACKGROUND

The delayed diagnosis of skin tumors is associated with a worsened prognosis. The impact of the interruption of clinical and surgical health services during the COVID-19 pandemic lockdowns has been documented among many pathologies. The impact of delayed diagnoses on patients with cutaneous squamous cell carcinomas (cSCCs) is poorly defined.

OBJECTIVE

To compare patient and lesion characteristics and the surgical management of excised cSCCs prior to the pandemic shutdown of services (2018-2019) with the phase following the pandemic's second wave (2021-2022).

METHODS

An observational, single-center, cross-sectional study of 416 surgically excised cSCCs over the course of two years was performed. Only patients with histologically confirmed cSCC were enrolled. Data collection included patient demographics and lesion characteristics, time to surgery, surgical approach, and histological data.

RESULTS

More cSCC lesions were excised prior to the interruption of services (n = 312 vs. n = 186). Lesions were significantly larger (1.7 ± 1.2 vs. 2.1 ± 1.5 cm; p = 0.006) and more invasive (52% vs. 89%; p < 0.001), in the period 2021-2022. Surgical reconstructive techniques were significantly different (p = 0.001). Metastatic involvement was confirmed in three subjects (one in 2018-2019 and two in 2021-2022). There were no significant differences in the time to surgery or patient characteristics. Multivariable regression analysis identified a 4.7-times higher risk of tumor invasion (OR 4.69, 95%CI 2.55-8.16, p < 0.001), a two-times higher chance of dermo-epidermal grafts (OR 2.06, 95%CI 1.09-3.88, p = 0.025), and a 3.2-times higher risk of positive surgical margins (OR 3.21, 95%CI 1.44-7.17, p = 0.004).

CONCLUSIONS

Diagnostic delays of cutaneous SCCs associated with reduced patient access to clinical and diagnostic services are associated with a 4.7-times increased risk of more severe invasion, a three-times increased risk of positive surgical margins, and a significant impact on surgical management, compared to the pre-pandemic period. Comparable patient cohort characteristics and time to surgery remained unchanged.

Allele-specific CRISPR-Cas9 editing of dominant epidermolysis bullosa simplex in human epidermal stem cells

Epidermolysis bullosa simplex (EBS) is a rare skin disease inherited mostly in an autosomal dominant manner. Patients display a skin fragility that leads to blisters and erosions caused by minor mechanical trauma. EBS phenotypic and genotypic variants are caused by genetic defects in intracellular proteins whose function is to provide the attachment of basal keratinocytes to the basement membrane zone and most EBS cases display mutations in keratin 5 (KRT5) and keratin 14 (KRT14) genes. Besides palliative treatments, there is still no long-lasting effective cure to correct the mutant gene and abolish the dominant negative effect of the pathogenic protein over its wild-type counterpart. Here, we propose a molecular strategy for EBS01 patient's keratinocytes carrying a monoallelic c.475/495del21 mutation in KRT14 exon 1. Through the CRISPR-Cas9 system, we perform a specific cleavage only on the mutant allele and restore a normal cellular phenotype and a correct intermediate filament network, without affecting the epidermal stem cell, referred to as holoclones, which play a crucial role in epidermal regeneration.

Generation of human induced pluripotent stem cell lines derived from three Noonan syndrome patients from a single family carrying the heterozygous PTPN11 c.188 A > G (p.Y63C) mutation

We have established Noonan syndrome (NS)-derived induced pluripotent stem cell (iPSC) lines derived from peripheral blood mononuclear cells (PBMCs) of a family cohort carrying the heterozygous PTPN11 c.188 A > G (p.Y63C) mutation. The new iPSC lines were validated by confirming the normal karyotype and targeted mutation, the pluripotent gene expression, and the differentiation capacity into three germ layers.

Researching the level of agreement among experts on terms used to describe wounds: An international study

Establishing a common language that allows univocal and objective communication in describing wounds and their healing is of utmost importance in defining the diagnostic hypothesis and proper wound management. To measure the level of agreement on the description of wounds, an international study was performed among experts of different professional backgrounds on several common terms used to describe ulcerative lesions. A panel of 27 wound care experts anonymously completed a multiple-choice questionnaire on 100 images of 50 ulcerative lesions. The participants were asked to describe each image using a set of pre-defined terms. An expert data analyst interpreted the questionnaires to map the level of agreement on the used terminology. Our findings show a very low level of agreement among experts in using the proposed terminology to describe the wound bed, the wound edge, and the surrounding skin conditions. Efforts should be planned to find a consensus on the correct use of terminology for wound description. To this aim, partnership, consensus, and agreement with educators in medicine and nursing are necessary.

G Protein-Dependent Activation of the PKA-Erk1/2 Pathway by the Striatal Dopamine D1/D3 Receptor Heteromer Involves Beta-Arrestin and the Tyrosine Phosphatase Shp-2

The heteromer composed of dopamine D1 and D3 receptors (D1R-D3R) has been defined as a structure able to trigger Erk1/2 and Akt signaling in a G protein-independent, beta-arrestin 1-dependent way that is physiologically expressed in the ventral striatum and is likely involved in the control of locomotor activity. Indeed, abnormal levels of D1R-D3R heteromer in the dorsal striatum have been correlated with the development of L-DOPA-induced dyskinesia (LID) in Parkinson's disease patients, a motor complication associated with striatal D1R signaling, thus requiring Gs protein and PKA activity to activate Erk1/2. Therefore, to clarify the role of the D1R/D3R heteromer in LID, we investigated the signaling pathway induced by the heteromer using transfected cells and primary mouse striatal neurons. Collectively, we found that in both the cell models, D1R/D3R heteromer-induced activation of Erk1/2 exclusively required the D1R molecular effectors, such as Gs protein and PKA, with the contribution of the phosphatase Shp-2 and beta-arrestins, indicating that heterodimerization with the D3R abolishes the specific D3R-mediated signaling but strongly allows D1R signals. Therefore, while in physiological conditions the D1R/D3R heteromer could represent a mechanism that strengthens the D1R activity, its pathological expression may contribute to the abnormal PKA-Shp-2-Erk1/2 pathway connected with LID.

Central nervous system interaction and crosstalk between nAChRs and other ionotropic and metabotropic neurotransmitter receptors

Neuronal nicotinic acetylcholine receptors (nAChRs) are widely distributed in both the peripheral and the central nervous systems. nAChRs exert a crucial modulatory influence on several brain biological processes; they are involved in a variety of neuronal diseases including Parkinson's disease, Alzheimer's disease, epilepsy, and nicotine addiction. The influence of nAChRs on brain function depends on the activity of other neurotransmitter receptors that co-exist with nAChRs on neurons. In fact, the crosstalk between receptors is an important mechanism of neurotransmission modulation and plasticity. This may be due to converging intracellular pathways but also occurs at the membrane level, because of direct physical interactions between receptors. In this line, this review is dedicated to summarizing how nAChRs and other ionotropic and metabotropic receptors interact and the relevance of nAChRs cross-talks in modulating various neuronal processes ranging from the classical modulation of neurotransmitter release to neuron plasticity and neuroprotection.

Are Parapoxvirus zoonotic diseases doomed to remain neglected?

Parapoxvirus (PPV) infections are considered neglected zoonoses because their incidence is often unknown or greatly underestimated despite being endemic globally. Here, we report the comprehensive diagnostic workflow that led to the identification of two cases of persistent PPV infections. The results obtained underline the importance of adopting a "One Health" approach and cross-sectoral collaboration between human and veterinary medicine for precise aetiological diagnosis and correct management of patients affected by zoonotic diseases.

Surgical management and oncological follow-up of cutaneous squamous cell carcinomas arising in epidermolysis bullosa patients

Background

Hereditary epidermolysis bullosa (EB) is a rare genodermatosis characterized by skin fragility and blistering of the skin and mucous membranes in reaction to minimal traumas. The development of cutaneous squamous cell carcinomas (cSCCs) is one of the most common medical complications in junctional and dystrophic forms of the disease. Complete surgical excision of cutaneous tumors represents the gold standard of treatment. However, not only recognition of cSCCs can be challenging in the affected skin but also wound closure after surgical excision poses a great therapeutic challenge in EB patients. The aim of our study was to analyze the postoperative outcomes of such patients in order to have a better knowledge of the main critical issues in their surgical management and oncological follow‐up.

Methods

We retrospectively identified a cohort of five EB patients treated at Modena University Hospital. Collected data included patient age and sex, date of cSCC diagnosis, relapses/recurrences, site of the neoplasm, number of surgical interventions, use of dermal substitutes, and postoperative infections.

Results

A total of 26 cSCCs were detected in our cohort. Forty‐one surgical interventions were necessary to achieve excision of cSCCs with clear margins, varying from 1 to 4 surgical sessions per cSCC. Dermal substitutes were used in most cases but carried a higher infectious risk.

Conclusions

EB patients tend to develop numerous cSCCs that often relapse even after complete excision with clear margins. These results stress the importance of early cSCC diagnosis and strict postsurgical follow‐up.

Ribociclib Cytotoxicity Alone or Combined With Progesterone and/or Mitotane in in Vitro Adrenocortical Carcinoma Cells

Mitotane is the only approved drug for treating adrenocortical carcinoma (ACC). The regimen added to mitotane is chemotherapy with etoposide, doxorubicin, and cisplatin. This pharmacological approach, however, has a limited efficacy and significant toxicity. Target-therapy agents represent a new promising approach to cancer therapy. Among these, a preeminent role is played by agents that interfere with cell-cycle progression, such as CDK4/6-inhibitors. Here, we investigate whether ribociclib could induce a cytotoxic effect both in ACC cell line and patient-derived primary cell cultures, alone or in combined settings. Cell viability was determined by 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide assay, whereas cell proliferation was evaluated by direct count. Binary combination experiments were performed using Chou and Talalay method. Gene expression was analyzed by quantitative RT-PCR, whereas protein expression was evaluated by immunofluorescence. A double staining assay revealed that ribociclib induced a prevalent apoptotic cell death. Cell-cycle analysis was performed to evaluate the effect of ribociclib treatment on cell-cycle progression in ACC cell models. Our results indicate that ribociclib was cytotoxic and reduced the cell proliferation rate. The effect on cell viability was enhanced when ribociclib was combined with progesterone and/or mitotane. The effect of ribociclib on cell-cycle progression revealed a drug-induced cell accumulation in G2 phase. The positive relationship underlined by our results between ribociclib, progesterone, and mitotane strengthen the clinical potential of this combination.

Structural Plasticity of Dopaminergic Neurons Requires the Activation of the D3R-nAChR Heteromer and the PI3K-ERK1/2/Akt-Induced Expression of c-Fos and p70S6K Signaling Pathway

We have previously shown that the heteromer composed by the dopamine D3 receptor (D3R) and the nicotinic acetylcholine receptor (nAChR) (D3R-nAChR heteromer) is expressed in dopaminergic neurons, activated by nicotine and represents the molecular unit that, in these neurons, contributes to the modulation of critical events such as structural plasticity and neuroprotection. We now extended this study by investigating the D3R-nAChR heteromer properties using various cell models such as transfected HEK293 cells, primary cultures of mouse dopaminergic neurons and human dopaminergic neurons derived from induced pluripotent stem cells.

We found that the D3R-nAChR heteromer is the molecular effector that transduces the remodeling properties not only associated with nicotine but also with D3R agonist stimulation: neither nAChR nor D3R, in fact, when express as monomers, are able to elicit these effects. Moreover, strong and sustained activation of the PI3K-ERK1/2/Akt pathways is coupled with D3R-nAChR heteromer stimulation, leading to the expression of the immediate-early gene c-Fos and to sustained phosphorylation of cytosolic p70 ribosomal S6 kinase (p70S6K), critical for dendritic remodeling. By contrast, while D3R stimulation results in rapid and transient activation of both Erk1/2 and Akt, that is PI3K-dependent, stimulation of nAChR is associated with persistent activation of Erk1/2 and Akt, in a PI3K-independent way. Thus, the D3R-nAChR heteromer and its ability to trigger the PI3K-ERK1/2/Akt signaling pathways may represent a novel target for preserving dopaminergic neurons healthy and for conferring neuronal protection against injuries.

Recent Advances in Dopamine D3 Receptor Heterodimers: Focus on Dopamine D3 and D1 Receptor-Receptor Interaction and Striatal Function

G protein-coupled receptors (GPCR) heterodimers represent new entities with unique pharmacological, signalling, and trafficking properties, with specific distribution restricted to those cells where the two interacting receptors are co-expressed. Like other GPCR, dopamine D3 receptors (D3R) directly interact with various receptors to form heterodimers: data showing the D3R physical interaction with both GPCR and non-GPCR receptors have been provided including D3R interaction with other dopamine receptors. The aim of this chapter is to summarize current knowledge of the distinct roles of heterodimers involving D3R, focusing on the D3R interaction with the dopamine D1 receptor (D1R): the D1R-D3R heteromer, in fact, has been postulated in both ventral and motor striatum. Interestingly, since both D1R and D3R have been implicated in several pathological conditions, including schizophrenia, motor dysfunctions, and substance use disorders, the D1R-D3R heteromer may represent a potential drug target for the treatment of these diseases.

The Potential Role of miRNAs in Cognitive Frailty

Frailty is an aging related condition, which has been defined as a state of enhanced vulnerability to stressors, leading to a limited capacity to meet homeostatic demands. Cognitive impairment is also frequent in older people, often accompanying frailty. Age is the main independent risk factor for both frailty and cognitive impairment, and compelling evidence suggests that similar age-associated mechanisms could underlie both clinical conditions. Accordingly, it has been suggested that frailty and cognitive impairment share common pathways, and some authors proposed "cognitive frailty" as a single complex phenotype. Nevertheless, so far, no clear common underlying pathways have been discovered for both conditions. microRNAs (miRNAs) have emerged as key fine-tuning regulators in most physiological processes, as well as pathological conditions. Importantly, miRNAs have been proposed as both peripheral biomarkers and potential molecular factors involved in physiological and pathological aging. In this review, we discuss the evidence linking changes of selected miRNAs expression with frailty and cognitive impairment. Overall, miR-92a-5p and miR-532-5p, as well as other miRNAs implicated in pathological aging, should be investigated as potential biomarkers (and putative molecular effectors) of cognitive frailty.

Prospective associations between childhood social communication processes and adolescent eating disorder symptoms in an epidemiological sample

Deficits in social cognition and communication, the processes associated with human social behavior and interaction, have been described in individuals with eating disorder psychopathology. The current study examined whether social communication characteristics present in middle childhood (ages 8-14) were associated with eating disorder behaviors, cognitions, and diagnoses across adolescence (ages 14-18) in a large, population-based sample. Participants (N = 4864) were children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC), a population-based, prospective study of women and their children. Regression methods tested prospective associations between social functioning using a facial emotion recognition task and parentally reported social communication symptoms (or difficulties), measured by the Social Communication Disorder Checklist (SCDC), with eating disorder symptoms and diagnoses. Misattribution of faces as sad or angry at age 8.5 was associated with purging and anorexia nervosa diagnosis at age 14, respectively, among girls. Furthermore, autistic-like social communication difficulties during middle childhood were associated with bulimia nervosa symptoms during adolescence among both girls and boys. Results did not support global associations between measured social communication deficits and eating disorder risk in this sample, but specific difficulties with facial emotion recognition and social communication may enhance the risk for disordered eating behaviors.

Extracellular clusterin limits the uptake of α-synuclein fibrils by murine and human astrocytes

The progressive neuropathological damage seen in Parkinson's disease (PD) is thought to be related to the spreading of aggregated forms of α-synuclein. Clearance of extracellular α-synuclein released by degenerating neurons may be therefore a key mechanism to control the concentration of α-synuclein in the extracellular space. Several molecular chaperones control misfolded protein accumulation in the extracellular compartment. Among these, clusterin, a glycoprotein associated with Alzheimer's disease, binds α-synuclein aggregated species and is present in Lewy bodies, intraneuronal aggregates mainly composed by fibrillary α-synuclein. In this study, using murine primary astrocytes with clusterin genetic deletion, human-induced pluripotent stem cell (iPSC)-derived astrocytes with clusterin silencing and two animal models relevant for PD we explore how clusterin affects the clearance of α-synuclein aggregates by astrocytes. Our findings showed that astrocytes take up α-synuclein preformed fibrils (pffs) through dynamin-dependent endocytosis and that clusterin levels are modulated in the culture media of cells upon α-synuclein pffs exposure. Specifically, we found that clusterin interacts with α-synuclein pffs in the extracellular compartment and the clusterin/α-synuclein complex can be internalized by astrocytes. Mechanistically, using clusterin knock-out primary astrocytes and clusterin knock-down hiPSC-derived astrocytes we observed that clusterin limits the uptake of α-synuclein pffs by cells. Interestingly, we detected increased levels of clusterin in the adeno-associated virus- and the α-synuclein pffs- injected mouse model, suggesting a crucial role of this chaperone in the pathogenesis of PD. Overall, our observations indicate that clusterin can limit the uptake of extracellular α-synuclein aggregates by astrocytes and, hence, contribute to the spreading of Parkinson pathology.

Modulation by chronic stress and ketamine of ionotropic AMPA/NMDA and metabotropic glutamate receptors in the rat hippocampus

Converging clinical and preclinical evidence has shown that dysfunction of the glutamate system is a core feature of major depressive disorder. In this context, the N-methyl-d-aspartate (NMDA) receptor antagonist ketamine has raised growing interest as fast acting antidepressant. Using the chronic mild stress (CMS) rat model of depression, performed in male rats, we aimed at analyzing whether hippocampal specific changes in subunit expression and regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) or NMDA ionotropic receptors and in metabotropic glutamate receptors could be associated with behavioral vulnerability/resilience to CMS. We also assessed whether acute ketamine (10 mg/kg) was able to dampen the alterations in CMS vulnerable animals. Although chronic stress and ketamine had no effect on ionotropic glutamate receptors mRNAs (expression, RNA editing and splicing), we found selective modulations in their protein expression, phosphorylation and localization at synaptic membranes. AMPA GluA2 expression at synaptic membranes was significantly increased only in CMS resilient rats (although a trend was found also in vulnerable animals), while its phosphorylation at Ser⁸⁸⁰ was higher in both CMS resilient and vulnerable rats, a change partially dampened by ketamine. In the hippocampus from all stressed groups, despite NMDA receptor expression levels were reduced in total extract, the levels of GluN2B-containing NMDA receptors were remarkably increased in synaptic membranes. Finally, mGlu2 underwent a selective downregulation in stress vulnerable animals, which was completely restored by acute ketamine. Overall, these results are in line with a hypofunction of activity-dependent glutamatergic synaptic transmission induced by chronic stress exposure in all the animals, as suggested by the alterations of ionotropic glutamate receptors expression and localization at synaptic level. At the same time, the selective modulation of mGlu2 receptor, confirms its previously hypothesized functional role in regulating stress vulnerability and, for the first time here, suggests a mGlu2 involvement in the fast antidepressant effect of ketamine.

Impaired dopamine D3 and nicotinic acetylcholine receptor membrane localization in iPSCs-derived dopaminergic neurons from two Parkinson's disease patients carrying the LRRK2 G2019S mutation

Mutations in the leucine-rich repeat kinase 2 (LRRK2) are the most common genetic determinants of Parkinson's disease (PD), with the G2019S accounting for about 3% of PD cases. LRRK2 regulates various cellular processes, including vesicle trafficking that is crucial for receptor localization at the plasma membrane. In this study, induced pluripotent stem cells derived from 2 PD patients bearing the G2019S LRRK2 kinase activating mutation were used to generate neuronal cultures enriched in dopaminergic neurons. The results show that mutant LRRK2 prevents the membrane localization of both the dopamine D3 receptors (D3R) and the nicotinic acetylcholine receptors (nAChR) and the formation of the D3R-nAChR heteromer, a molecular unit crucial for promoting neuronal homeostasis and preserving dopaminergic neuron health. Interestingly, D3R and nAChR as well as the corresponding heteromer membrane localization were rescued by inhibiting the abnormally increased kinase activity. Thus, the altered membrane localization of the D3R-nAChR heteromer associated with mutation in LRRK2 might represent a pre-degenerative feature of dopaminergic neurons contributing to the special vulnerability of this neuronal population.

Comparison of two perioperative antibiotic schedules in patients undergoing surgical reconstruction with dermal matrix after excision of skin cancer

Perioperative antibiotic treatment duration in skin reconstruction with dermal substitutes is not well established. This study compares the incidence of infective complications after two different durations of perioperative antibiotic treatment in patients undergoing surgical reconstruction with skin dermal substitutes (SDS) after excision of skin cancer. Infective complications at the site of SDS were compared in subjects undergoing surgical reconstruction who received either a > 24-hour (extended protocol) or a ≤ 24-hour (short protocol) perioperative antibiotic treatment. Of 116 patients undergoing SDS surgical reconstruction, 62 (53.4%) received an extended schedule, and 54 (46.6%) received a short schedule. The two groups were similar for gender, age, comorbidities, American Society of Anesthesiologists score, and type of skin cancer. Overall incidence rate of infection was 20.7% (24/116). No differences in terms of risk of infection were observed between the two groups (OR: 1.04, 95% CI: 0.42-2.55; P = .937). Patients undergoing SDS reconstruction in the limb/foot had a higher risk of infection in comparison with those undergoing SDS reconstruction in the chest/head (OR: 2.69, 95% CI: 1.06-6.86; P = .038). The short protocol was demonstrated to be beneficial to patients undergoing surgical reconstruction with SDS. A ≤ 24-hour perioperative antibiotic schedule did not increase the infection rate, potentially allowing a reduction of antibiotic exposure.

Dopamine D3 Receptor Heteromerization: Implications for Neuroplasticity and Neuroprotection

The dopamine (DA) D3 receptor (D3R) plays a pivotal role in the control of several functions, including motor activity, rewarding and motivating behavior and several aspects of cognitive functions. Recently, it has been reported that the D3R is also involved in the regulation of neuronal development, in promoting structural plasticity and in triggering key intracellular events with neuroprotective potential. A new role for D3R-dependent neurotransmission has thus been proposed both in preserving DA neuron homeostasis in physiological conditions and in preventing pathological alterations that may lead to neurodegeneration. Interestingly, there is evidence that nicotinic acetylcholine receptors (nAChR) located on DA neurons also provide neurotrophic support to DA neurons, an effect requiring functional D3R and suggesting the existence of a positive cross-talk between these receptor systems. Increasing evidence suggests that, as with the majority of G protein-coupled receptors (GPCR), the D3R directly interacts with other receptors to form new receptor heteromers with unique functional and pharmacological properties. Among them, we recently identified a receptor heteromer containing the nAChR and the D3R as the molecular effector of nicotine-mediated neurotrophic effects. This review summarizes the functional and pharmacological characteristics of D3R, including the capability to form active heteromers as pharmacological targets for specific neurodegenerative disorders. In particular, the molecular and functional features of the D3R-nAChR heteromer will be especially discussed since it may represent a possible key etiologic effector for DA-related pathologies, such as Parkinson’s disease (PD), and a target for drug design.

P1110Role of an extensive diagnostic work-up in the detection of concealed cardiomyopathies in athletes with complex ventricular arrhythmias and implications for sports" eligibility assessment

Background

ventricular Arrhythmias (VAs) are a common clinical problem and a critical issue with regards to sports" eligibility in athletes. Although VAs can be considered a benign feature of the athlete’s heart adaptive phenotype, they may also be the only clinical manifestation of a concealed cardiomyopathy, potentially heralding sudden cardiac death (SCD) during sports activity.

Purpose

to evaluate the diagnostic contribution and the implications for sports eligibility assessment of a thorough non-invasive and invasive work-up including electrophysiology study (EPS), electroanatomical mapping (EAM) and endomyocardial biopsy (EMB) in athletes with complex VAs and to derive a multiparametric risk score in order to easily predict structural heart diseases’ diagnosis.

Methods

we conducted a prospective, single-arm, open-label single center, observational study. All consecutive athletes presenting for evaluation at our institution after being disqualified from participating in sports due to complex VAs were enrolled. The athletes underwent a baseline non-invasive diagnostic protocol with transthoracic echocardiogram and gadolinium enhanced cardiac magnetic resonance imaging (cMRI). Subsequently EPS, EAM and EAM-guided EMB were performed if deemed necessary. Sports eligibility status was re-assessed at 6 months’ follow-up. A multivariable logistic regression model was built, considering cMRI as the gold standard exam.

Results

after diagnostic evaluation, 55 subjects (26.4%) had a diagnosis of heart disease, most commonly myocarditis (n = 27) and arrhythmogenic right ventricular cardiomyopathy (ARVC, n = 16). After 6 months, 100 athletes (48.1%) were judged eligible to participate in competitive sports and 46 subjects (22.1%) were deemed eligible to participate in non-competitive sports. On multivariable logistic-regression analysis, abnormalities on ECG (OR 5.3) or on echocardiogram (OR 3.7), sustained VA inducibility on EPS (OR 17.7) and low-voltage areas on EAM (OR 7.7) proved all predictive of concealed structural heart diseases’ diagnosis. We derived two simple risk scores: a 40-points risk score and an 8-points risk score (obtained by weighing each variable according to the regression model’s ORs). Both these risk scores’ performance proved very good (AUC = 0.856 for the 40-points score and AUC = 0.852 for the 8-points score, figure 1).

Conclusions

approximately 1/4 of athletes presenting with complex VAs have a concealed heart disease, most commonly myocarditis or ARVC. ECG, echocardiogram and EAM abnormalities and sustained VAs inducibility on EPS are predictive of structural heart diseases’ detection. Therefore, these diagnostic tests should be routinely included in the evaluation of athletes with complex VAs. A risk score including the results of these tests can greatly help in the prediction of concealed structural heart diseases’ diagnosis. More than 2/3 of subjects were judged eligible to participate in sports at 6 months’ follow-up.

Abstract Figure 1. ROC curves for diagnosis