Vitamin D receptor exhibits different pharmacodynamic features in tumoral and normal microenvironments: A molecular modeling study

The vitamin D receptor (VDR) constitutes a promising therapeutic target for the treatment of cancer. Unfortunately, its natural agonist calcitriol does not have clinical utility due to its potential to induce hypercalcemic effects at the concentrations required to display antitumoral activity. For this reason, the search for new calcitriol analogues with adequate therapeutic profiles has been actively pursued by the scientific community. We have previously reported the obtaining and the biological activity evaluation of new calcitriol analogues by modification of its sidechain, which exhibited relevant antiproliferative and selectivity profiles against tumoral and normal cells. In this work we conducted molecular modeling studies (i.e. molecular docking, molecular dynamics, constant pH molecular dynamics (CpHMD) and free energy of binding analysis) to elucidate at an atomistic level the molecular basis related to the potential of the new calcitriol analogues to achieve selectivity between tumoral and normal cells. Two histidine residues (His305 and His397) were found to exhibit a particular tautomeric configuration that produces the observed bioactivity. Also, different acid-based properties were observed for His305 and His307 with His305 showing an increased acidity (pKa 5.2) compared to His397 (pKa 6.8) and to the typical histidine residue. This behavior favored the pharmacodynamic interaction of the calcitriol analogues exhibiting selectivity for tumoral cells when VDR was modeled at the more acidic tumoral environment (pH ≅ 6) compared to the case when VDR was modeled at pH 7.4 (normal cell environment). On the other hand, non-selective compounds, including calcitriol, exhibited a similar interaction pattern with VDR when the receptor was modeled at both pH conditions. The results presented constitute the first evidence on the properties of the VDR receptor in different physicochemical environments and thus represent a significant contribution to the in silico screening and design of new calcitriol analogues.

Antitumoral effects of the alkynylphosphonate analogue of calcitriol EM1 on glioblastoma multiforme cells

Glioblastoma multiforme (GBM) is the worst and most common brain tumor, characterized by high proliferation and invasion rates. The current standard treatment is mainly based on chemoradiotherapy and this approach has slightly improved patient survival. Thus, novel strategies aimed at prolonging the survival and ensuring a better quality of life are necessary. In the present work, we investigated the antitumoral effect of the novel analogue of calcitriol EM1 on GBM cells employing in vitro, in silico, and in vivo assays. In vitro, we demonstrated that EM1 treatment selectively decreases the viability of murine and human tumor cells without affecting that of normal human astrocytes. The analysis of the mechanisms showed that EM1 produces cell cycle arrest in the T98G cell line, which is accompanied by an increase in p21, p27, p57 protein levels and a decrease in cyclin D1, p-Akt-S473, p-ERK1/2 and c-Jun expression. Moreover, EM1 treatment also exerts in GBM cells anti-migratory effects and decreases their invasive capacity by a reduction in MMP-9 proteolytic activity. In silico, we demonstrated that EM1 is able to bind to the vitamin D receptor with greater affinity than calcitriol. Finally, we showed that EM1 treatment of nude mice administered at 50ug/kg body weight during 21days neither induces hypercalcemia nor toxicity effects. In conclusion, all the results indicate the potential of EM1 analogue as a promising therapeutic alternative for GBM treatment.

A Straightforward Methodology for the Synthesis of α,ω-Telechelic Poly(dimethylsiloxane)s

In this work we report the synthesis of α,ω-telechelic poly(dimethylsiloxane)s (α,ω-PDMS) by employing a novel bifunctional initiator obtained from a commercially available siloxane precursor, diglycidylether-terminated poly(dimethylsiloxane) (PDMS-DGE). The synthetic strategy was easily followed by different colour changes, and involved the high-vacuum reaction of sec-Bu−Li+ with 1,1′-diphenylethylene (DPE) to afford the addition adduct (bright red) that was subsequently reacted with PDMS-DGE, promoting the nuclephilic ring-opening from epoxide-end chains. The resulting bifunctional initiator (light green) was then employed to polymerize hexamethyl(cyclotrisiloxane) monomer (D3) by using conventional anionic polymerization (from light green to pale yellow). From suitable terminating agents, silane (–SiH), vinyl (–CH=CH2), hydroxy (–OH), and even methacryloyl α,ω-PDMS were obtained. 1H NMR and FT-IR analyses confirmed the presence of the targeted functional groups in the resulting polymers. However, a careful siliconization procedure should be performed over glass surfaces during the fractionation of chlorosilane ampoules in order to avoid the presence of silanol moieties that decrease end-capping efficiency. This fact was observed not only from NMR but also from size exclusion chromatography (SEC) analyses, since narrow molar masses distributions (1.15 ≤ Mw/Mn ≤ 1.3) and a good control over the resulting molar masses were observed.

Antidepressants and the risk of arrhythmia in elderly affected by a previous cardiovascular disease: a real-life investigation from Italy

PURPOSE

The study aimed to fill existing knowledge gaps on the safety of antidepressant drugs (ADs) by estimating the risk of hospitalization for arrhythmia associated with use of selective serotonin reuptake inhibitors (SSRIs) and newer atypical ADs (NAAs) among elderly with previous cardiovascular (CV) events.

METHODS

The cohort was composed by 199,569 individuals aged ≥ 65 years from five Italian healthcare territorial units who were discharged for cardiovascular outcomes in the years 2008-2010. The 17,277 patients who experienced hospital admission for arrhythmia during follow-up were included as cases. Odds of current ADs use among cases (i.e., 14 days before hospital admission) was compared with (i) odds of current use of 1:5 matched controls (between-patients case-control) and with (ii) odds of previous use during 1:5 matched control periods (within-patient case-crossover). The risk of arrhythmia associated with ADs current use was modelled fitting a conditional logistic regression. A set of sensitivity analyses was performed to account for sources of systematic uncertainty.

RESULTS

Current users of SSRIs and NAAs were at increased risk of arrhythmia with case-control odds ratios (OR) of 1.37 (95% confidence interval, CI 1.18 to 1.58) and 1.41 (1.16 to 1.71) and case-crossover OR of 1.48 (1.20 to 1.81) and 1.72 (1.31 to 2.27). An increased risk of arrhythmia was associated with current use of trazodone (NAA) consistently in case-control and case-crossover designs.

CONCLUSIONS

Evidence that current use of SSRIs and NAAs is associated to an increased risk of arrhythmia among elderly with CV disease was consistently supplied by two observational approaches.

Thunderstorm-related asthma: what happens and why

The fifth report issued by the Intergovernmental Panel on Climate Change forecasts that greenhouse gases will increase the global temperature as well as the frequency of extreme weather phenomena. An increasing body of evidence shows the occurrence of severe asthma epidemics during thunderstorms in the pollen season, in various geographical zones. The main hypotheses explaining association between thunderstorms and asthma claim that thunderstorms can concentrate pollen grains at ground level which may then release allergenic particles of respirable size in the atmosphere after their rupture by osmotic shock. During the first 20-30 min of a thunderstorm, patients suffering from pollen allergies may inhale a high concentration of the allergenic material that is dispersed into the atmosphere, which in turn can induce asthmatic reactions, often severe. Subjects without asthma symptoms, but affected by seasonal rhinitis can also experience an asthma attack. All subjects affected by pollen allergy should be alerted to the danger of being outdoors during a thunderstorm in the pollen season, as such events may be an important cause of severe exacerbations. In light of these observations, it is useful to predict thunderstorms and thus minimize thunderstorm-related events.

New and old roles of the peripheral and brain renin-angiotensin-aldosterone system (RAAS): Focus on cardiovascular and neurological diseases

It is commonly accepted that the renin-angiotensin-aldosterone system (RAAS) is a cardiovascular circulating hormonal system that plays also an important role in the modulation of several patterns in the brain. The pathway of the RAAS can be divided into two classes: the traditional pathway of RAAS, also named classic RAAS, and the non-classic RAAS. Both pathways play a role in both cardiovascular and neurological diseases through a peripheral or central control. In this regard, renewed interest is growing in the last years for the consideration that the brain RAAS could represent a new important therapeutic target to regulate not only the blood pressure via central nervous control, but also neurological diseases. However, the development of compounds able to cross the blood-brain barrier and to act on the brain RAAS is challenging, especially if the metabolic stability and the half-life are taken into consideration. To date, two drug classes (aminopeptidase type A inhibitors and angiotensin IV analogues) acting on the brain RAAS are in development in pre-clinical or clinical stages. In this article, we will present an overview of the biological functions played by peripheral and brain classic and non-classic pathways of the RAAS in several clinical conditions, focusing on the brain RAAS and on the new pharmacological targets of the RAAS.

Near fatal asthma: treatment and prevention

Near-fatal asthma (NFA) is described as acute asthma associated with a respiratory arrest or arterial carbon dioxide tension greater than 50 mmHg, with or without altered consciousness, requiring mechanical ventilation. Risk factors for near fatal asthma have not been fully elucidated. In 80-85% of all fatal events, a phenotype, characterized by eosinophilic inflammation associated with gradual deterioration occurring in patients with severe and poorly controlled asthma, has been identified. Regarding to the management, acute severe asthma remains a significant clinical problem, which needs to be identified to facilitate early and appropriate therapeutic interventions. The assessment relies on clinical signs, but additional information might be obtained from chest radiography or blood gas analysis. No investigation should delay the initiation of appropriate therapy. The goals of therapy are the maintenance of oxygenation, relief of airflow obstruction, reduction of airways edema and mucus plugging (with Increased use of medications such as beta-agonists via metered dose inhalers and nebulizers, oral and/or intravenous (other than by inhalation) corticosteroids and oral or intravenous theophylline) whereas supporting ventilation as clinically indicated. Of course, the emergency physician needs to consider the wide range of potential complications, as attention to these problems when managing severe acute asthma might significantly improve outcome. An understanding of the available agents and potential pitfalls in the management of NFA is mandatory for the emergency physician.

Incidence and prognostic impact of other cancers in a population of long-term survivors of chronic lymphocytic leukemia

BACKGROUND

Information on the impact of other cancers (OCs) in long-term survivors (LTSs) of chronic lymphocytic leukemia (CLL) is limited.

PATIENTS AND METHODS

Patients with CLL who survived >10 years were defined as LTSs of CLL. We calculated standardized incidence ratios (SIRs) to compare the incidence of OC in LTS of CLL versus the general population. A multivariable model was used to identify independent predictors of OC. Overall survival was analyzed as a function of the presence of OC.

RESULTS

Among 797 LTSs of CLL, the cumulative frequency of OC was 36%, similar between 570 patients (72%) who required treatment for CLL (TRT) and 227 (28%) who remained untreated (UT). The most common OC in both groups was non-melanoma skin cancer, followed by prostate cancer, breast cancer, melanoma, lung cancer, and leukemia in TRT patients, and by prostate cancer, breast cancer, melanoma, lung cancer, and gastrointestinal tumors in the UT group. The SIR for all OC was 1.2 (P = 0.034). It was higher in males (SIR 1.31; P = 0.013) and patients <60 years (SIR 1.27; P = 0.027). A higher SIR was shown for secondary leukemia, melanoma, and head-and-neck cancers, whereas a lower SIR was found for gastrointestinal and bladder cancers. Independent predictors of OC development were advanced age, male gender, and lower platelets. The survival of patients with OC was 16.2 months and that of patients without OC 22.9 years.

CONCLUSIONS

LTSs of CLL have an increased incidence of OC compared with the general population. CLL therapy is not a risk factor for OC in LTSs of CLL. The presence of an OC in these patients may be associated with shorter survival.

The alkynylphosphonate analogue of calcitriol EM1 has potent anti-metastatic effects in breast cancer

The active form of vitamin D3, calcitriol, plays a major role in maintaining calcium/phosphate homeostasis. In addition, it is a potent antiproliferative and prodifferentiating agent. However, when effective antitumor doses of calcitriol are employed, hypercalcemic effects are observed, thus precluding its therapeutic application. To overcome this problem, structural analogues have been designed with the aim at retaining or even increasing the antitumor effects while decreasing its calcemic activity. This report shows the biological evaluation of an alkynylphosphonate vitamin D less-calcemic analogue in a murine model of breast cancer. We demonstrate that this compound has potent anti-metastatic effects through its action over cellular migration and invasion likely mediated through the up-regulation of E-cadherin expression. Based on the current in vitro and in vivo results, EM1 is a promising candidate as a therapeutic agent in breast cancer.

Hunting for origins of migraine pain: cluster analysis of spontaneous and capsaicin-induced firing in meningeal trigeminal nerve fibers

Trigeminal nerves in meninges are implicated in generation of nociceptive firing underlying migraine pain. However, the neurochemical mechanisms of nociceptive firing in meningeal trigeminal nerves are little understood. In this study, using suction electrode recordings from peripheral branches of the trigeminal nerve in isolated rat meninges, we analyzed spontaneous and capsaicin-induced orthodromic spiking activity. In control, biphasic single spikes with variable amplitude and shapes were observed. Application of the transient receptor potential vanilloid 1 (TRPV1) agonist capsaicin to meninges dramatically increased firing whereas the amplitudes and shapes of spikes remained essentially unchanged. This effect was antagonized by the specific TRPV1 antagonist capsazepine. Using the clustering approach, several groups of uniform spikes (clusters) were identified. The clustering approach combined with capsaicin application allowed us to detect and to distinguish "responder" (65%) from "non-responder" clusters (35%). Notably, responders fired spikes at frequencies exceeding 10 Hz, high enough to provide postsynaptic temporal summation of excitation at brainstem and spinal cord level. Almost all spikes were suppressed by tetrodotoxin (TTX) suggesting an involvement of the TTX-sensitive sodium channels in nociceptive signaling at the peripheral branches of trigeminal neurons. Our analysis also identified transient (desensitizing) and long-lasting (slowly desensitizing) responses to the continuous application of capsaicin. Thus, the persistent activation of nociceptors in capsaicin-sensitive nerve fibers shown here may be involved in trigeminal pain signaling and plasticity along with the release of migraine-related neuropeptides from TRPV1 positive neurons. Furthermore, cluster analysis could be widely used to characterize the temporal and neurochemical profiles of other pain transducers likely implicated in migraine.

Cognitive performances and DAT imaging in early Parkinson's disease with mild cognitive impairment: a preliminary study

OBJECTIVES

Mild cognitive impairment (MCI) is a common feature in Parkinson's disease (PD). We performed an exploratory study to investigate dopaminergic nigrostriatal innervation and its cognitive correlates in early untreated PD patients with MCI as compared to cognitively intact patients.

PATIENTS AND METHODS

A consecutive series of 34-de-novo, drug-naïve patients with PD were enrolled. They underwent [123-I] FP-CIT SPECT and comprehensive neuropsychological battery. MCI was identified in 15 of 34 patients with PD.

RESULTS

The two groups did not show any statistically significant difference in age, sex, disease duration, education, lateralization, and H&Y and Hospital Anxiety and Depression Scale scores. Logistic regression analysis showed that UPDRS-III was weakly associated with MCI (P = 0.034). Partial correlation analysis controlling for UPDRS-III and age suggested that in PD patients with MCI reduced V3″ values in the more affected caudate were correlated with reduced performances in frontal assessment battery, Trail Making Test: part B minus Part A and copy task of the Rey-Osterrieth complex figure test. Reduced V3″ values in the more and less affected putamen were significantly related with reduced performance in frontal assessment battery and in copy task of Rey-Osterrieth complex figure test, respectively. No correlation was found between neuropsychological scores and DAT availability in PD patients without MCI.

CONCLUSIONS

Although preliminary, our results suggest that striatal dopamine depletion may contribute to some cognitive deficit in early never treated PD patients with MCI.

Increased bilirubin levels in de novo Parkinson's disease

BACKGROUND AND PURPOSE

Oxidative stress is a central pathogenic mechanism of Parkinson's disease (PD), and the heme oxygenase (HO) bilirubin pathway is one of the main mammalian antioxidative defences. Indeed, there is growing evidence of HO-bilirubin upregulation from early phases of PD. Our aim was to investigate bilirubin as a possible biomarker of PD diagnosis and progression.

METHODS

A cross-sectional case-control study was performed to evaluate differences in bilirubin levels between newly diagnosed, drug-naïve PD subjects and controls. Afterwards, PD subjects were included in a 2-year longitudinal study to evaluate disease progression in relation to baseline bilirubin levels.

RESULTS

Seventy-five de novo PD subjects were selected and matched with 75 controls by propensity score. Analysis of variance showed higher bilirubin levels in PD patients compared with controls (P < 0.001). Linear regression analysis failed to show a relationship between bilirubin and Unified Parkinson's Disease Rating Scale (UPDRS) part III (P = 0.283) at baseline evaluation. At 2-year follow-up, indirect relationships between bilirubin levels and UPDRS part III (P = 0.028) and between bilirubin levels and levodopa-equivalent daily dosage (P = 0.012) were found.

CONCLUSIONS

Parkinson's disease subjects showed higher levels of bilirubin compared with controls. Bilirubin increase might be due to HO overexpression as a compensatory response to oxidative stress occurring from early stages of PD.

Uric acid relates to dopamine transporter availability in Parkinson's disease

BACKGROUND

Diagnosing Parkinson's disease (PD) and tracking its progression may require the combination of reliable biomarkers. Among them, both serum uric acid (UA) and dopamine transporter (DaT) binding deserve more investigations.

AIMS OF THE STUDY

We aimed to investigate the relationship between serum UA levels and DaT availability in newly diagnosed, drug-naïve PD patients, by means of semiquantitative [(123) I]FP-CIT-SPECT.

METHODS

We recruited 52 newly diagnosed, drug-naïve PD patients, and performed serum UA dosage and [(123) I]FP-CIT-SPECT.

RESULTS

Pearson's correlation analysis showed that UA levels were significantly higher in patients with higher averaged, ipsilateral and contralateral DaT binding in caudate, putamen, and striatum.

CONCLUSIONS

We showed, for the first time, by regional semiquantitative analysis of DaT binding in PD patients that UA levels significantly correlates with the severity of dopaminergic impairment in caudate, putamen, and striatum. This study broadens our knowledge on the importance of UA as a biomarker of PD.

Cervico-Oculo-Acoustic Syndrome in a Male with Consanguineous Parents

Background:

The cervico-oculo-acoustic syndrome comprises Klippel-Feil anomaly, sensorineural deafness and Duane's retraction syndrome. Polygenic, autosomal dominant, and X-linked inheritance have been hypothesized. The disorder has rarely been reported in males.

Case Report:

A 42-year-old male, born of consanguineous parents, presented with Duane's syndrome, mixed hearing loss, C2-C3 fusion, neck stiffness, and right facial palsy. A variety of cardiac, neurological and urogenital anomalies occurred in his relatives. The electro-oculographic studies showed impaired abduction and adduction of the right eye and impaired abduction of the left eye. Vergence, vertical eye movements and peripheral vestibular responses were normal. Somatosensory evoked potentials showed absence of the N13 peak and brainstem auditory evoked potentials bilateral delay of the I-III interpeak latencies.

Conclusions:

Consanguinity of the patient's parents, not previously reported, suggests autosomal recessive inheritance, but autosomal dominant inheritance is indicated by the family history. The pattern of the oculomotor deficit is consistent with bilateral dysplasia of the abducens nuclei with preserved internuclear neurons in the right abducens nucleus. Neurophysiological investigations revealed lower brainstem and cervical cord involvement.

A (single case) rehabilitation program based on cueing for freezing of speech

BACKGROUND

Freezing of speech (FoS) and other repetitive speech behaviours can frequently occur in parkinsonian syndromes, worsening the efficacy of language functioning, hampering social interactions, and thus reducing quality of life. Pharmacological treatment are ineffective and other interventions have not specifically developed so far.

AIM

The aim of this paper was to test the efficacy on a pilot rehabilitation program for freezing of speech based on cueing.

SETTING

Outpatient clinic.

POPULATION

Single-case.

METHODS

We developed a pilot rehabilitation program based on visual, auditory and sensory cueing. The patient underwent the protocol for a 6-month period (1-hour sessions, 3 times weekly). Perceptual analyses of his speech were performed before and after the rehabilitation program by to different blinded reviewers.

RESULTS

There has been a reduction of FoS and other iterative speech episodes. Intelligibility also improved according to both the patient and his relatives.

CONCLUSION

Our preliminary results show that visual, auditory and sensory cueing can be effective to prevent and overcome FoS episodes. Possible underlying mechanisms of the improvement are discussed.

CLINICAL REHABILITATION IMPACT

Rehabilitation programs based on cueing should be considered and offered in Parkinsonian patients exhibiting FoS or other iterative speech phenomena.