1,720,968 research outputs found
Microbiota e difetto immune nella patogenesi della malattia di Crohn: sviluppo di modelli per lo studio di possibili approcci correttivi non immuno-soppressivi
No full textLa malattia di Crohn(MC)è una malattia infiammatoria cronica dell’intestino che può colpire qualsiasi tratto del tubo digerente. Nonostante siano stati effettuati numerosi studi, la patogenesi della MC non è ancora chiara e non si dispone di trattamenti in grado di guarire stabilmente la malattia. Il sistema immunitario innato sembra giocare un ruolo fondamentale nella patogenesi: è stato osservato infatti un coinvolgimento di alcuni geni dell’immunità innata ed uno squilibrato rapporto tra sistema immune mucosale e microbiota intestinale. Dati clinici e genetici portano a pensare che alla base della patogenesi stiano un difettoso funzionamento dell’immunità innata mucosale e una risposta infiammatoria adattativa compensatoria. Lo sviluppo di modelli adeguati a studiare la complessità di questa malattia risulta difficile per la molteplicità di fattori coinvolti, genetici e ambientali.
L’obiettivo di questa tesi è stato quello di sviluppare dei modelli che tenessero conto della complessità della patologia e che permettessero di evidenziare dei profili tipici di risposta a componenti batteriche.
Il primo approccio ex vivo sviluppato ha analizzato le diverse pathway di attivazione in monociti circolanti, per evidenziare l’eventuale presenza di un difetto di riposta dell’immunità innata. Da questo test è emerso che i pazienti affetti da MC non sembrano presentare un difetto di risposta, bensì un’iperattivazione delle pathways innate, testimoniata da un’aumentata produzione monocitaria di TNFα. Questo stato infiammatorio, riscontrabile sia in condizione basale sia in seguito a stimolazione di alcuni recettori innati, non è riconducibile né al genotipo di NOD2 (analizzate le principali mutazioni associate a malattia) né all’attività di malattia dei pazienti presi in analisi, né alla presenza in circolo di componenti batteriche (segno di traslocazione batterica intestinale).
Il secondo modello sviluppato ha analizzato direttamente la risposta immunologica mucosale nel tessuto intestinale, più pertinente alla patogenesi della malattia rispetto alle cellule presenti nel circolo periferico. Attraverso una cultura ex vivo di biopsie coliche in presenza o assenza di antibiotici, si è voluto valutare l’influenza del microbiota sulla secrezione citochinica. Con un’analisi logistica multivariata, è stato possibile dimostrare l’esistenza di un profilo citochinico (G-CSF, TNFα, IL4 e IL17) in grado di discriminare la MC dalla rettocolite ulcerosa. E’ stato quindi dimostrato che la MC e la rettocolite ulcerosa presentano differenti profili di risposta citochinica e che la flora batterica associata a mucosa è in grado di modulare la risposta mucosale.
Con il terzo approccio è stata valutata la risposta cellulare di una linea epiteliale intestinale a diversi composti di origine microbica, utilizzando un sistema automatizzato che fornisce in tempo reale informazioni sulla crescita, adesione, morfologia e vitalità cellulare. Da questa analisi è emerso che solo il composto purificato di derivazione micobatterica è in grado di indurre un’alterazione temporanea della cinetica cellulare; questa variazione non è dovuta alla morte cellulare, ma probabilmente ad una variazione della permeabilità del simil-epitelio ricreato in vitro. Ulteriori test sono necessari per far chiarezza sull’effetto dato da questo composto sulla mucosa intestinale, visto il ruolo controverso del Mycobacterium Avium paratubercolis nella patogenesi della MC.
In conclusione, in questi tre anni è stato possibile sviluppare diversi modelli per evidenziare specifici profili di risposta mucosale tipici della MC, su cui studiare l’effetto di nuove strategie terapeutiche correttive, basate sulla modulazione dell’interazione tra immunità mucosale e microbiota intestinale. I risultati ottenuti sono stati oggetto di due pubblicazioni sulla rivista internazionale “World Journal of Gastroenterology”
Repositioning Of Tak-475 In Mevalonate Kinase Disease: Translating Theory Into Practice
Full text linkMevalonate Kinase Deficiency (MKD, OMIM #610377) is a rare autosomal recessive metabolic and inflammatory disease. In MKD, defective function of the enzyme mevalonate kinase (MK), due to a mutation in the MVK gene, leads to the shortage of mevalonate-derived intermediates, which results in unbalanced prenylation of proteins and altered metabolism of sterols. These defects lead to a complex multisystem inflammatory and metabolic syndrome. Although biologic therapies aimed at blocking the inflammatory cytokine interleukin-1 (IL-1) can significantly reduce inflammation, they cannot completely control the clinical symptoms that affects the nervous system. For this reason, MKD can still be considered an orphan drug disease. Cellular models for MKD can be obtained by biochemical inhibition of mevalonate-derived isoprenoids. Of note, these cells present an exaggerated response to inflammatory stimuli that can be reduced by treatment with zaragozic acid, an inhibitor of squalene synthase (SQS) able to increase the availability of isoprenoids intermediates upstream the enzymatic block. A similar action might be obtained by lapaquistat acetate (TAK-475, Takeda), a drug that underwent extensive clinical trials as a cholesterol lowering agent 10 years ago, with a good safety profile. Here we describe the preclinical evidence supporting the possible repositioning of TAK-475 from its originally intended use to the treatment of MKD and discuss its potential to modulate the mevalonate pathway in inflammatory diseases
Types of Food and Nutrient Intake in India: A Literature Review.
No full textNowadays India is undergoing an impressive economic growth accompanied by a very slow decline, almost stagnation, in malnutrition levels. In developing countries, studies on dietary patterns and their relationship with nutritional status are scarce. Over the years some nutritional studies have been performed to explore different types of food consumed in various Indian regions, among different social samples. The aim of the present paper is to review and describe trends in food and nutrition intake patterns in the different states of India. The review was carried out in PubMed, using the advanced research criteria: [food* OR ("meal pattern*") OR ("eating pattern*")] AND ("nutrient intake") AND India*. PubMed research gave back 84 results and out of these, 7 papers due to their focus on food intake and consumption levels in India have been included in this study. Food intake patterns showed that most of the Indians are vegetarians and that food items rich in micronutrients (pulses, other vegetables, fruits, nuts, oilseeds and animal foods) are generally consumed less frequently. Poor and monotonous cereals-based diet may promote inadequate nutrition intakes according to Recommended Daily Allowance (RDA) standards
Inhibition of mesenchymal stromal cells by pre-activated lymphocytes and their culture media.
No full textIntroduction:
Despite having a proven immunosuppressive potential in vitro, human mesenchymal stromal cells (MSCs) are reported to display variable efficacy in vivo and, in fact, their proven benefit in the clinical practice is still limited and controversial.
Methods:
The interplay between clinical grade MSCs and pre-activated donor lymphocytes or selected lymphocyte subsets was studied in vitro. The kinetics of MSC growth and viability was evaluated by adhesion-dependent changes of culture plate impedance and biochemically by a colorimetric assay. Activation of natural killer (NK) cells was assessed as well, using a flow cytometry assay.
Results:
A strong inhibition of MSC growth was rapidly induced by the addition of pre-activated lymphocytes but not of resting lymphocytes. Inhibition seems not to be attributable to a single cell population, as similar results can be obtained by depleting NK cells or by using either selected CD4+ or CD8+ lymphocytes. In addition, conditioned medium (CM) from activated lymphocytes was able to inhibit MSC growth in a dose-dependent manner. Furthermore, licensing with IFN-γ partially protected MSCs from pre-activated lymphocytes but not from their CM. These results suggest an inhibitory role of lymphocyte-activation-derived substances. However, the identification of a single molecule responsible for MSC inhibition remained elusive, even if preliminary experiments showed that ATP and, to a lesser extent, TNF-α might play a role.
Conclusions:
These results suggest that survival of MSCs can be affected by soluble mediators released by activated lymphocytes. Thus it can be hypothesized that MSC immunosuppressive action in vivo could be impaired by ongoing immune activation through the release of inflammatory mediators
Action of methotrexate and tofacitinib on directly stimulated and bystander-activated lymphocytes
No full textChronic inflammation associated with autoim- mune activation is characteristic of rheumatic diseases from childhood to adulthood. In recent decades, signi cant improvements in the treatment of these types of disease have been achieved using disease modifying anti-rheumatic drugs (DMARDs), such as methotrexate (MTX) and, more recently, using biologic inhibitors. The recent introduction of kinase inhibitors (for example, tofacitinib; Tofa) further increases the available ARDs. However, there are patients that do not respond to any treatment strategies, for whom combination therapies are proposed. The data regarding the combined action of different drugs is lacking and the knowledge of the mechanisms of ARDs and their actions upon pathogenic lymphocytes, which are hypothesized to sustain disease, is poor. An in vitro model of in ammation was developed in the current study, in which stimulated and unstimulated lymphocytes were cultured together, but tracked separately, to investigate the action of MTX and Tofa on the two populations. By analysing lymphocyte proliferation and activation, and cytokine secretion in the culture supernatants, it was estab- lished that, due to the presence of activated cells, unstimulated cells underwent a bystander activation that was modulated by the ARDs. Additionally, varying administration schedules were demonstrated to affect lymphocytes differently in vitro, either directly or via bystander activation. Furthermore, MTX and Tofa exerted different effects; while MTX showed an antiproliferative effect, Tofa marginally effected activation, although only a slight antiproliferative action, which could be potentiated by sequential treatment with MTX. Thus, it was hypothesized that these differences may be exploited in sequential therapeutic strategies, to maximize the anti-rheu- matic effect. These ndings are notable and must be accounted for, as bystander-activated cells in vivo could contribute to the spread of autoimmune activation and disease progression
The diagnostic challenge of very early-onset enterocolitis in an infant with XIAP deficiency
Full text linkBackground: Aggressive course and resistance to treatments usually characterize very early onset inflammatory bowel disease (VEO-IBD). Some VEO-IBD cases are due to monogenic immune defects and can benefit from hematopoietic stem cell transplantation (HSCT). Case presentation: We describe a Caucasian male baby who presented in the first months of life macrophage activation syndrome, followed by intractable colitis, recurrent episodes of fever and mild splenomegaly. After several immunological, genetic and clinical investigations, subsequently a therapeutic attempt with colectomy, analysis of VEO-IBD-associated genes, revealed a causative mutation in XIAP. The genetic diagnosis of a primary immune deficiency allowed curing the boy with hematopoietic stem cell transplantation. Conclusion: Our report, together with novel findings from recent literature, should contribute to increase awareness of monogenic immune defects as a cause of VEO-IBD. Comprehensive genetic analysis can allow a prompt diagnosis, resulting in the choice of effective treatments and sparing useless and damaging procedures
Altered pattern of tumor necrosis factor-Alpha production in peripheral blood monocytes from Crohn's disease basic study
No full textAIM:
To evaluate the inflammatory state in Crohn's disease (CD) patients and correlate it with genetic background and microbial spreading.
METHODS:
By means of flow cytometry, production of tumor necrosis factor-alpha (TNF-α) was measured in peripheral blood monocytes from patients suffering from CD, ulcerative colitis (UC) and in healthy subjects after stimulation of the NOD2 and TLR pathways. CD patients were genotyped for the three most common NOD2 variants (R702W, G908R and L1007Pfs*2) and basal production of TNF-α was correlated to NOD2 genotype. Also, production of TNF-α was correlated to plasmatic levels of LPS Binding Protein (LBP), soluble (s) CD14 and to the activity state of the disease.
RESULTS:
The patients with CD were characterized by a significantly higher monocyte basal expression of TNF-α compared with healthy subjects and UC patients, and after stimulation with Pam3CSK4 (ligand of TLR2/1) and MDP-L18 (ligand of NOD2) this difference was maintained, while other microbial stimuli (LPS, ligand of TLR4 and PolyI:C, ligand of TLR3) induced massive activation in CD monocytes as well as in UC and in healthy control cells. There was no significant difference in the production of TNF-α between patients who carried CD-associated heterozygous or homozygous variants in NOD2 and patients with wild type NOD2 genotype. Although serum LBP levels have been shown to correlate positively with the state of activity of the disease, TNF-α production did not show a clear correlation with either LBP or sCD14 levels in plasma. Moreover, no clear correlation was seen between TNF-α production and activity indices in either CD or UC.
CONCLUSION:
Peripheral monocytes from CD express higher basal and stimulated TNF-α than controls, regardless of NOD2 genotype and without a clear correlation with disease activity
Innovative Target Therapies Are Able to Block the Inflammation Associated with Dysfunction of the Cholesterol Biosynthesis Pathway.
Full text linkThe cholesterol pathway is an essential biochemical process aimed at the synthesis of bioactive molecules involved in multiple crucial cellular functions. The end products of this pathway are sterols, such as cholesterol, which are essential components of cell membranes, precursors of steroid hormones, bile acids and other molecules such as ubiquinone. Several diseases are caused by defects in this metabolic pathway: the most severe forms of which cause neurological involvement (psychomotor retardation and cerebellar ataxia) as a result of a variety of cellular impairments, including mitochondrial dysfunction. These pathologies are induced by convergent mechanisms in which the mitochondrial unit plays a pivotal role contributing to defective apoptosis, autophagy and mitophagy processes. Unraveling these mechanisms would contribute to the development of effective drug treatments for these disorders. In addition, the development of biochemical models could have a substantial impact on the understanding of the mechanism of action of drugs that act on this pathway in multifactor disorders. In this review we will focus in particular on inhibitors of cholesterol synthesis, mitochondria-targeted drugs and inhibitors of the inflammasom
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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