Farmacogenetica delle malattie infiammatorie croniche intestinali pediatriche

2010/2011Le malattie infiammatorie croniche intestinali (MICI) comprendono due patologie distinte, la malattia di Crohn (MC) e la rettocolite ulcerosa (RCU), che pur essendo diverse dal punto di vista patogenetico, presentano aspetti clinici comuni quali la presenza di infiammazione cronica a diversi livelli del tratto gastrointestinale e l'alternanza tra fasi attive ed inattive della malattia. Queste patologie hanno un picco di incidenza nell’adulto, tuttavia piu' di un terzo dei casi insorge prima dei sedici anni. L'approccio terapeutico e' principalmente diretto al trattamento e controllo dell'infiammazione, attraverso farmaci capaci di indurre e mantenere la remissione della malattia, che tuttavia inducono effetti avversi importanti, particolarmente rilevanti nella popolazione pediatrica. Nonostante l'introduzione in clinica di farmaci biologici altamente efficaci, i glucocorticoidi (GC) continuano a rappresentare la terapia di prima linea per indurre la remissione nel MC e nella RCU in fase di attività moderata o severa. La risposta clinica a questi farmaci è tuttavia estremamente variabile, e al momento non ci sono validi marcatori che permettano di predire quali saranno i pazienti che risponderanno in maniera adeguata e quali al contrario non risponderanno o andranno incontro a effetti collaterali. Dopo un ciclo iniziale con i GC, la terapia viene continuata con altri immunosoppressori, che negli ultimi anni vengono utilizzati sempre più precocemente, proprio per cercare di aumentare l’efficacia e di limitare le complicanze da steroidi. Tra gli immunosoppressori più utilizzati vi sono le tiopurine 6-MP e AZA: quest’ultima è la tiopurina più utilizzata nelle MICI pediatriche. Una prima parte della ricerca si è occupata di studiare retrospettivamente su pazienti pediatrici con MICI la farmacogenetica degli steroidi, con l’obiettivo di identificare marcatori che possano essere utili a predire la risposta clinica a questi farmaci. In parallelo, è stata analizzata la farmacogenetica e farmacocinetica dell’AZA, con lo scopo di ottimizzare il trattamento con questo farmaco in pazienti pediatrici con MICI, permettendo di aggiustare i dosaggi e di evitare trattamenti destinati all’insuccesso. La farmacogenetica degli steroidi è stata studiata su 154 pazienti con MICI che sono stati suddivisi in base alla risposta clinica in responders (84), dipendenti (55) e resistenti (15): è stato dimostrato un effetto significativo del polimorfismo BclI del gene NR3C1 che codifica per il recettore dei GC, e del polimorfismo Leu155His del gene NALP1, proteina coinvolta nell’attivazione della pro-IL-1 a IL-1, sulla risposta ai GC. Questa associazione è stata dimostrata mediante analisi univariate (responders vs non responders p=0.02) e multivariate (responders vs non responders p=0.03) e confermata anche esaminando il modello con l’analisi CART. Quest’analisi conferma il significativo effetto dei polimorfismi BclI e Leu155His sulla risposta ai GC con modalità indipendente, ed indica come altre importanti variabili il sesso e l’età all’esordio della malattia. In conclusione, i risultati ottenuti indicano che fattori genetici (polimorfismi BclI del gene NR3C1 e Leu155His del gene NALP1) e variabili cliniche (età all’esordio e sesso) potrebbero rappresentare degli importanti marker di risposta ai GC in pazienti pediatrici con MICI. Le correlazioni tra farmacocinetica e farmacogenetica dell’AZA sono state studiate in 77 pazienti pediatrici affetti da MICI, in trattamento con farmaci tiopurinici da almeno 3 mesi. I risultati ottenuti confermano un effetto del polimorfismo dell’enzima TPMT sui metaboliti attivi delle tiopurine in accordo con quanto riportato precedentemente in letteratura, confermando l’importante ruolo di questo enzima sul metabolismo dell’AZA. E’ stato inoltre dimostrato un effetto significativo dell’isoforma M dell’enzima GST sui metaboliti dell’AZA: soggetti con delezione del gene presentano una concentrazione più bassa dei metaboliti attivi 6-TGN (p=0.010) ed un rapporto TGN/dose più basso (p=0.0002): l’isoforma M dell’enzima GST è coinvolta nella conversione dell’AZA in 6-MP; nei soggetti deleti meno AZA verrebbe convertita in 6-MP a sua volta pro farmaco del metabolita attivo 6-TGN. Inoltre, le concentrazioni dei metaboliti metilati sono significativamente più alte nei pazienti con un genotipo variante per il polimorfismo C94A del gene ITPA rispetto ai pazienti con genotipo wild type (p=0.046), mentre non è evidente una correlazione con i metaboliti 6-TGN. Studi prospettici dovranno essere realizzati in futuro, per valutare l’efficacia di strategie di dosaggio dell’AZA basate sulla quantificazione dei metaboliti e sull’analisi dei polimorfismi degli enzimi TPMT, GST-M e ITPA per migliorare la risposta al farmaco e ridurre gli effetti avversi. E’ stato inoltre messo a punto un modello sperimentale in vitro su colture primarie di cellule mononucleate, su cui testare l’inibizione della proliferazione indotta da mitogeno sia dei GC che dell’AZA, attraverso il saggio d’incorporazione della timidina triziata. I dati ottenuti con il test in vitro sono stati poi correlati con la presenza di polimorfismi genetici degli enzimi coinvolti nella farmacogenetica di questi farmaci, con l’obiettivo di standardizzare una metodica che dovrebbe permettere di predire la risposta alla terapia prima di iniziare il trattamento. E’ stata osservata una maggiore sensibilità in vitro ai GC nei soggetti mutati per il polimorfismo BclI: questo SNP è risultato infatti essere associato ad una IC50 (concentrazione di farmaco che inibisce il 50% della proliferazione cellulare) più bassa, in confronto ai soggetti non mutati (p=0.0058). Questo risultato è confermato anche considerando l’Imax (l’inibizione della proliferazione cellulare alla concentrazione di farmaco più alta): soggetti con genotipo mutato per BclI presentano un’Imax più alta rispetto ai non mutati (p=0.0078). Sulla base di questi risultati, si conferma il ruolo importante del polimorfismo BclI nella risposta ai GC, già dimostrata nello studio retrospettivo, come marker genetico di risposta ai GC. Lo studio sulla sensibilità dell’AZA sui linfociti di volontari sani, non ha evidenziato correlazioni statististicamente significative tra i polimorfismi degli enzimi coinvolti nel metabolismo dell’AZA, e la sensibilità individuale a questo farmaco in vitro. Questa mancata correlazione, può derivare dal fatto che il metabolismo dell’AZA è principalmente di tipo epatico, e i linfociti probabilmente non rappresentano un buon modello per questo studio: esperimenti futuri riguarderanno l’utilizzo di linee cellulari epatiche, su cui verrà testata l’alterata sensibilità all’AZA e 6-MP, in condizioni di ipersespressione o silenziamento dei geni di nostro interesse, tra cui GST. Nel complesso, questa tesi ha sviluppato un set di valutazioni farmacologiche, integranti dati di farmacocinetica, farmacodinamica e farmacogenomica, da applicare all'ottimizzazione della terapia delle MICI pediatriche con steroidi ed AZA, in modo da aumentarne l'efficacia e ridurrne gli effetti avversi. I markers che sono risultati essere correlati ad un’alterata risposta a questi farmaci potrebbero essere utilizzati dal clinico per selezionare i pazienti responders dai non responders, e per trattare questi ultimi con associazioni di altri immunosoppressori in maniera precoce.XXIV Ciclo197

Environmental awareness and firm creation

Purpose This study tests whether environmental awareness affects firm creation by using Google Trends data and a novel region-level data set from Italy. Design/methodology/approach Forward-looking entrepreneurs drive firm creation. The authors hypothesize that more environmentally conscious entrepreneurs will emerge as environmental awareness rises, increasing the number of green and energy firms. The authors test the prediction using Google Trends data and a novel region-level data set from Italy. Findings The authors find that not only the number of green and energy-innovative firms but also that of all innovative start-ups increases with rising environmental consciousness. The results imply some “innovation spillover” effects from green sectors to other industries with rising environmental awareness. Originality/value The paper hypothesizes that as environmental awareness rises, more environmental-conscious entrepreneurs will emerge, which would increase the number of green and energy firms. Robustness and falsification tests are also offered

Role of the Long Non-Coding RNA Growth Arrest-Specific 5 in Glucocorticoid Response in Children with Inflammatory Bowel Disease

Glucocorticoids (GCs) are widely employed in inflammatory, autoimmune and neoplastic diseases, and, despite the introduction of novel therapies, remain the first-line treatment for inducing remission in inflammatory bowel disease (IBD). Given the high incidence of suboptimal response, associated with a significant number of side-effects, that are particularly severe in paediatric patients, the identification of subjects that are most likely to respond poorly to GCs is extremely important. Recent evidence suggests that the long non-coding RNA (lncRNA) GAS5 could be a potential marker of GC resistance. To address this issue, we evaluated the association between the lncRNA GAS5 and the efficacy of steroids, in terms of inhibition of proliferation, in two cell lines derived from colon and ovarian cancers, to confirm the sensitivity and specificity of these lncRNAs. These cells showed a different sensitivity to GCs and revealed differential expression of GAS5 after treatment. GAS5 was up-regulated in GC-resistant cells and accumulated more in the cytoplasm compared to the nucleus in response to the drug. The functions of GAS5 were assessed by silencing, and we found that GAS5 knock-down reduced the proliferation during GC treatment. Furthermore, for the first time, we measured GAS5 levels in 19 paediatric IBD patients at diagnosis and after the first cycle of GCs, and we demonstrated an up-regulation of the lncRNA in patients with unfavourable steroid response. Our preliminary results indicate that GAS5 could be considered a novel pharmacogenomic marker useful for the personalization of GC therapy

Role of Oxidative Stress Mediated by Glutathione-S-transferase in Thiopurines' Toxic Effects

Azathioprine (AZA), 6-mercaptopurine (6-MP), and 6-thioguanine (6-TG) are antimetabolite drugs, widely used as immunosuppressants and anticancer agents. Despite their proven efficacy, a high incidence of toxic effects in patients during standard-dose therapy is recorded. The aim of this study is to explain, from a mechanistic point of view, the clinical evidence showing a significant role of glutathione-S-transferase (GST)-M1 genotype on AZA toxicity in inflammatory bowel disease patients. To this aim, the human nontumor IHH and HCEC cell lines were chosen as predictive models of the hepatic and intestinal tissues, respectively. AZA, but not 6-MP and 6-TG, induced a concentration-dependent superoxide anion production that seemed dependent on GSH depletion. N-Acetylcysteine reduced the AZA antiproliferative effect in both cell lines, and GST-M1 overexpression increased both superoxide anion production and cytotoxicity, especially in transfected HCEC cells. In this study, an in vitro model to study thiopurines' metabolism has been set up and helped us to demonstrate, for the first time, a clear role of GST-M1 in modulating AZA cytotoxicity, with a close dependency on superoxide anion production. These results provide the molecular basis to shed light on the clinical evidence suggesting a role of GST-M1 genotype in influencing the toxic effects of AZA treatment

Thiopurine metabolites variations during co-treatment with aminosalicylates for inflammatory bowel disease: effect of N-acetyl transferase polymorphisms

AIM: To evaluate variation of the concentration of thiopurine metabolites after 5-aminosalicylate (5-ASA) interruption and the role of genetic polymorphisms of N-acetyl transferase (NAT) 1 and 2. METHODS: Concentrations of thioguanine nucleotides (TGN) and methymercaptopurine nucleotides (MMPN), metabolites of thiopurines, were measured by high performance liquid chromatography in 12 young patients (3 females and 9 males, median age 16 years) with inflammatory bowel disease (6 Crohn's disease and 6 ulcerative colitis) treated with thiopurines (7 mercaptopurine and 5 azathioprine) and 5-ASA. Blood samples were collected one month before and one month after the interruption of 5-ASA. DNA was extracted and genotyping of NAT1, NAT2, inosine triphosphate pyrophosphatase (ITPA) and thiopurine methyl transferase (TPMT) genes was performed using PCR assays. RESULTS: Median TGN concentration before 5-ASA interruption was 270 pmol/8 x 108 erythrocytes (range: 145-750); after the interruption of the aminosalicylate, a 35% reduction in TGN mean concentrations (absolute mean reduction 109 pmol/8 7 108 erythrocytes) was observed (median 221 pmol/8 7 108 erythrocytes, range: 96-427, P value linear mixed effects model 0.0011). Demographic and clinical covariates were not related to thiopurine metabolites concentrations. All patients were wild-type for the most relevant ITPA and TPMT variants. For NAT1 genotyping, 7 subjects presented an allele combination corresponding to fast enzymatic activity and 5 to slow activity. NAT1 genotypes corresponding to fast enzymatic activity were associated with reduced TGN concentration (P value linear mixed effects model 0.033), putatively because of increased 5-ASA inactivation and consequent reduced inhibition of thiopurine metabolism. The effect of NAT1 status on TGN seems to be persistent even after one month since the interruption of the aminosalicylate. No effect of NAT1 genotypes was shown on MMPN concentrations. NAT2 genotyping revealed that 6 patients presented a genotype corresponding to fast enzymatic activity and 6 to slow activity; NAT2 genotypes were not related to thiopurine metabolites concentration in this study. CONCLUSION: NAT1 genotype affects TGN levels in patients treated with thiopurines and aminosalicylates and could therefore influence the toxicity and efficacy of these drugs; however the number of patients evaluated is limited and this has to be considered a pilot study

Long Noncoding RNA GAS5: A Novel Marker Involved in Glucocorticoid Response

Glucocorticoids (GCs) exert their effects through regulation of gene expression after activation in the cytoplasm of the glucocorticoid receptor (GR) encoded by NR3C1 gene. A negative feedback mechanism resulting in GR autoregulation has been demonstrated through the binding of the activated receptor to intragenic sequences called GRE-like elements, contained in GR gene. The long noncoding RNA growth arrest-specific transcript 5 (GAS5) interacts with the activated GR suppressing its transcriptional activity. The aim of this study was to evaluate the possible role of GAS5 and NR3C1 gene expression in the antiproliferative effect of methylprednisolone in peripheral blood mononuclear cells and to correlate the expression with individual sensitivity to GCs. Subjects being poor responders to GCs presented higher levels of GAS5 and NR3C1 in comparison with good responders. We suggest that abnormal levels of GAS5 may alter GC effectiveness, probably interfering with the mechanism of GR autoregulation

Prevalence of chronic pain syndrome in patients who have undergone hallux valgus percutaneous surgery: a comparison of sciatic-femoral and ankle regional ultrasound-guided nerve blocks

Background: Chronic pain syndrome (CPS) is a common complication after operative procedures, and only a few studies have focused on the evaluation of CPS in foot-forefoot surgery and specifcally on HV percutaneous correc‑ tion. The objective of this study was to compare postoperative pain levels and incidence of CPS in two groups of patients having undergone femoral-sciatic nerve block or ankle block regional anaesthesia before hallux valgus (HV) percutaneous surgery and the association between postoperative pain levels and risk factors between these patient groups. Methods: A consecutive patient series was enrolled and evaluated prospectively at 7 days, 1, 3 and 6 months after surgery. The participants were divided into two groups according to the regional anaesthesia received, femoral-sciatic nerve block or ankle block, and their outcomes were compared. The parameters assessed were postoperative pain at rest and during movement by the numerical rating scale (NRS), patient satisfaction using the Visual Analogue Scale (VAS), quality of life and return to daily activities. Statistical analysis was performed. Results: One hundred fifty-five patients were assessed, 127 females and 28 males. Pain at rest (p 0.05), quality of life significantly increased and patients returned to daily activities and work (p < 0.0001). No significant impact of type of anaesthesia could be detected. ASA 3 (p = 0.043) was associated to higher pain during movement; BMI (p = 0.005) and lumbago (p = 0.004) to lower satisfaction. No operative-anaesthetic complications were recorded. Postoperative pain at rest and during movement improved over time independently of the regional block used, with low incidence of CPS at last follow-up. Among risk factors, only a higher ASA was associated to higher pain during movement, while higher BMI and lumbago to lower satisfaction. Conclusions: Both ultrasound-guided sciatic-femoral and ankle blocks were safe and effective in reducing postoperative pain with low incidence of CPS at last follow-up

Long non-coding RNA gas5 and intestinal mmp2 and mmp9 expression: A translational study in pediatric patients with IBD

Background: The long non-coding RNA (lncRNA) growth arrest–specific transcript 5 (GAS5) seems to be involved in the regulation of mediators of tissue injury, in particular matrix metalloproteinases (MMPs), implicated in the pathogenesis of inflammatory bowel disease (IBD). We investigated the role of GAS5 in regulating MMP2 and MMP9 expression in pediatric patients with IBD and in vitro. Methods: In total, 25 IBD patients were enrolled: For each patient paired inflamed and non-inflamed biopsies were collected. RNA was extracted and GAS5, MMP2, and MMP9 were quantified by TaqMan assay. The expression of GAS5 and MMPs was also determined in the human monocytic THP1 cells differentiated into macrophages and stimulated with lipopolysaccharide (LPS). The function of GAS5 was assessed by overexpressing the lncRNA and evaluating the MMPs levels. Results: Real-time PCR results demonstrated a downregulation of GAS5 and an upregulation of both MMPs in inflamed tissues. In vitro data confirmed the trend observed in patients for the three genes: The stimulation with LPS promoted a downregulation of GAS5 while an increase of MMPs was observed. Overexpression experiments showed that higher levels of GAS5 lead to a decrease of both enzymes. Conclusion: These results provide new information about the role of GAS5 in IBD: The lncRNA could mediate tissue damage by modulating the expression of MMPs