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Alessio Fasano

Publications and source records attributed to Alessio Fasano.

At least 19 recordsLinked to original sources
PubMed2025

Targeting the SARS-CoV-2 reservoir in long COVID.

There are no approved treatments for post-COVID-19 condition (also known as long COVID), a debilitating disease state following SARS-CoV-2 infection that is estimated to affect tens of millions of people. A growing body of evidence shows that SARS-CoV-2 can persist for months or years following COVID-19 in a subset of individuals, with this reservoir potentially driving long-COVID symptoms or sequelae. There is, therefore, an urgent need for clinical trials targeting persistent SARS-CoV-2, and several trials of antivirals or monoclonal antibodies for long COVID are underway. However, because mechanisms of SARS-CoV-2 persistence are not yet fully understood, such studies require important considerations related to the mechanism of action of candidate therapeutics, participant selection, duration of treatment, standardisation of reservoir-associated biomarkers and measurables, optimal outcome assessments, and potential combination approaches. In addition, patient subgroups might respond to some interventions or combinations of interventions, making post-hoc analyses crucial. Here, we outline these and other key considerations, with the goal of informing the design, implementation, and interpretation of trials in this rapidly growing field. Our recommendations are informed by knowledge gained from trials targeting the HIV reservoir, hepatitis C, and other RNA viruses, as well as precision oncology, which share many of the same hurdles facing long-COVID trials.

Humans↗
PubMed2007

A prospective, double-blind, placebo-controlled trial to establish a safe gluten threshold for patients with celiac disease.

BACKGROUND: Treatment of celiac disease (CD) is based on the avoidance of gluten-containing food. However, it is not known whether trace amounts of gluten are harmful to treated patients. OBJECTIVE: The objective was to establish the safety threshold of prolonged exposure to trace amounts of gluten (ie, contaminating gluten). DESIGN: This was a multicenter, double-blind, placebo-controlled, randomized trial in 49 adults with biopsy-proven CD who were being treated with a gluten-free diet (GFD) for > or =2 y. The background daily gluten intake was maintained at < 5 mg. After a baseline evaluation (t0), patients were assigned to ingest daily for 90 d a capsule containing 0, 10, or 50 mg gluten. Clinical, serologic, and histologic evaluations of the small intestine were performed at t0 and after the gluten microchallenge (t1). RESULTS: At t0, the median villous height/crypt depth (Vh/Cd) in the small-intestinal mucosa was significantly lower and the intraepithelial lymphocyte (IEL) count (x 100 enterocytes) significantly higher in the CD patients (Vh/Cd: 2.20; 95% CI: 2.11, 2.89; IEL: 27; 95% CI: 23, 34) than in 20 non-CD control subjects (Vh/Cd: 2.87; 95% CI: 2.50, 3.09; IEL: 22; 95% CI: 18, 24). One patient (challenged with 10 mg gluten) developed a clinical relapse. At t(1), the percentage change in Vh/Cd was 9% (95% CI: 3%, 15%) in the placebo group (n = 13), -1% (-18%, 68%) in the 10-mg group (n = 13), and -20% (-22%, -13%) in the 50-mg group (n = 13). No significant differences in the IEL count were found between the 3 groups. CONCLUSIONS: The ingestion of contaminating gluten should be kept lower than 50 mg/d in the treatment of CD.

Adult↗
PubMed2006

Tight junction modulation and its relationship to drug delivery.

In order for therapeutic agents to exert their pharmacological effects, they have to cross the biological membranes into the systemic circulation and reach the site of action. Drugs cross the membranes by one of two pathways; paracellular or transcellular. Most drugs are transported transcellularly depending on their physiocochemical properties, however the paracellular route is usually the main route of absorption for hydrophilic drugs (proteins, peptides, etc.). The paracellular pathway is governed by the tight junctions (TJs). The modulation of the TJs by absorption enhancers for paracellular drug transport enhancement and hence drug delivery improvement has been hampered for so many years by lack of comprehensive understanding of the structure and function of the TJs. The TJs are a multiple unit structure composed of multiprotein complex that affiliates with the underlying apical actomyosin ring. TJ proteins identified include transmembrane proteins; occludin and claudin, and cytoplasmic plaque proteins; ZO-1, ZO-2, ZO-3, cingulin, and 7H6. Among the new absorption enhancers that evolved in the past few years is Zonula Occludens toxin, Zot. In vivo and in vitro studies have shown that Zot and its biologically active fragment DeltaG could be effectively used to increase the transport/absorption of paracellular markers and low bioavailable drugs across the intestinal epithelium. Above all, the transient opening of the TJs by Zot suggests that it could be used as a novel approach for the safe drug delivery of therapeutic agents.

Animals↗
PubMed2006

Gliadin stimulation of murine macrophage inflammatory gene expression and intestinal permeability are MyD88-dependent: role of the innate immune response in Celiac disease.

Recent studies have demonstrated the importance of TLR signaling in intestinal homeostasis. Celiac disease (CD) is an autoimmune enteropathy triggered in susceptible individuals by the ingestion of gliadin-containing grains. In this study, we sought to test the hypothesis that gliadin initiates this response by stimulating the innate immune response to increase intestinal permeability and by up-regulating macrophage proinflammatory gene expression and cytokine production. To this end, intestinal permeability and the release of zonulin (an endogenous mediator of gut permeability) in vitro, as well as proinflammatory gene expression and cytokine release by primary murine macrophage cultures, were measured. Gliadin and its peptide derivatives, 33-mer and p31-43, were found to be potent inducers of both a zonulin-dependent increase in intestinal permeability and macrophage proinflammatory gene expression and cytokine secretion. Gliadin-induced zonulin release, increased intestinal permeability, and cytokine production were dependent on myeloid differentiation factor 88 (MyD88), a key adapter molecule in the TLR/IL-1R signaling pathways, but were neither TLR2- nor TLR4-dependent. Our data support the following model for the innate immune response to gliadin in the initiation of CD. Gliadin interaction with the intestinal epithelium increases intestinal permeability through the MyD88-dependent release of zonulin that, in turn, enables paracellular translocation of gliadin and its subsequent interaction with macrophages within the intestinal submucosa. There, the interaction of gliadin with macrophages elicits a MyD88-dependent proinflammatory cytokine milieu that facilitates the interaction of T cells with APCs, leading ultimately to the Ag-specific adaptive immune response seen in patients with CD.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines.

OBJECTIVE: Little is known about the interaction of gliadin with intestinal epithelial cells and the mechanism(s) through which gliadin crosses the intestinal epithelial barrier. We investigated whether gliadin has any immediate effect on zonulin release and signaling. MATERIAL AND METHODS: Both ex vivo human small intestines and intestinal cell monolayers were exposed to gliadin, and zonulin release and changes in paracellular permeability were monitored in the presence and absence of zonulin antagonism. Zonulin binding, cytoskeletal rearrangement, and zonula occludens-1 (ZO-1) redistribution were evaluated by immunofluorescence microscopy. Tight junction occludin and ZO-1 gene expression was evaluated by real-time polymerase chain reaction (PCR). RESULTS: When exposed to gliadin, zonulin receptor-positive IEC6 and Caco2 cells released zonulin in the cell medium with subsequent zonulin binding to the cell surface, rearrangement of the cell cytoskeleton, loss of occludin-ZO1 protein-protein interaction, and increased monolayer permeability. Pretreatment with the zonulin antagonist FZI/0 blocked these changes without affecting zonulin release. When exposed to luminal gliadin, intestinal biopsies from celiac patients in remission expressed a sustained luminal zonulin release and increase in intestinal permeability that was blocked by FZI/0 pretreatment. Conversely, biopsies from non-celiac patients demonstrated a limited, transient zonulin release which was paralleled by an increase in intestinal permeability that never reached the level of permeability seen in celiac disease (CD) tissues. Chronic gliadin exposure caused down-regulation of both ZO-1 and occludin gene expression. CONCLUSIONS: Based on our results, we concluded that gliadin activates zonulin signaling irrespective of the genetic expression of autoimmunity, leading to increased intestinal permeability to macromolecules.

Animals↗
PubMed2006

Zonula occludens toxin synthetic peptide derivative AT1002 enhances in vitro and in vivo intestinal absorption of low molecular weight heparin.

Zonula occludens toxin (Zot) is an enterotoxin obtained from the bacterium vibrio cholerae that has been shown to reversibly and safely open the tight junctions and enhance paracellular transport. AT1002 is a novel synthetic hexapeptide derived from Zot. The hypothesis to be tested in this study is that AT1002 enhances the oral absorption of ardeparin, a low molecular weight heparin (LMWH). To test this hypothesis, drug transport through Caco-2 cell monolayers was monitored in the presence and absence of AT1002. Regional permeability studies using rat intestine were performed. Cell viability in the presence of various concentrations of enhancer was determined. The absorption of ardeparin after oral administration in rats was measured by anti-factor Xa assay. Furthermore, the eventual mucosal and epithelial damage was histologically evaluated. Higher ardeparin permeability (approximately 2-fold) compared to control was observed in the presence of 0.025% of AT1002. Regional permeability studies revealed that the permeability of ardeparin across the duodenal membrane was improved by the AT1002. Cell viability studies showed no significant cytotoxicity below 0.0028% of AT1002. In the presence of 100 microg/kg of AT1002, ardeparin oral bioavailability was significantly increased (F(relative/s.c) approximately 20.5%). Furthermore, AT1002 at a dose of 100 microg/kg did not induce any observable morphological damage on gastrointestinal (GI) tissues in vivo. These in vivo and in vitro results suggest that the co-administration of LMWH with AT1002 may be a useful delivery strategy to increase its permeability and hence oral absorption.

Administration, Oral↗
PubMed2006

Systemic autoimmune disorders in celiac disease.

PURPOSE OF REVIEW: Celiac disease is an immune-mediated disorder clinically characterized by a multitude of symptoms and complications. The comorbidity between celiac disease and other autoimmune disorders has been clearly established. RECENT FINDINGS: Two main theories have been postulated to explain this comorbidity: (1) linkage disequilibrium between the genes responsible for celiac disease and those responsible for the coexpressed autoimmune diseases or (2) untreated celiac disease leading to the onset of other autoimmune diseases. This article reviews the current literature supporting either theory and places the current knowledge in the field within the context of the most recent data on the pathogenesis of celiac disease. SUMMARY: The current literature did not clearly establish which of the two theories explain the comorbidity between celiac disease and other autoimmune disorders. There is, however, growing evidence that the loss of the intestinal barrier function typical of celiac disease could be responsible of the onset of other autoimmune disease. This concept implies that the autoimmune response can be theoretically stopped and perhaps reversed if the interplay between autoimmune predisposing genes and trigger(s) is prevented or eliminated by a prompt diagnosis and treatment.

Animals↗
PubMed2006

Zonulin upregulation is associated with increased gut permeability in subjects with type 1 diabetes and their relatives.

Zonulin, a protein that modulates intestinal permeability, is upregulated in several autoimmune diseases and is involved in the pathogenesis of autoimmune diabetes in the BB/Wor animal model of the disease. To verify the association between serum zonulin levels and in vivo intestinal permeability in patients with type 1 diabetes, both parameters were investigated in different stages of the autoimmune process. Forty-two percent (141 of 339) of the patients had abnormal serum zonulin levels, as compared with age-matched control subjects. The increased zonulin levels correlated with increased intestinal permeability in vivo and changes in claudin-1, claudin-2, and myosin IXB genes expression, while no changes were detected in ZO1 and occludin genes expression. When tested in serum samples collected during the pre-type 1 diabetes phase, elevated serum zonulin was detected in 70% of subjects and preceded by 3.5 +/- 0.9 years the onset of the disease in those patients who went on to develop type 1 diabetes. Combined, these results suggest that zonulin upregulation is associated with increased intestinal permeability in a subgroup of type 1 diabetic patients. Zonulin upregulation seems to precede the onset of the disease, providing a possible link between increased intestinal permeability, environmental exposure to non-self antigens, and the development of autoimmunity in genetically susceptible individuals.

Autoimmune Diseases↗
PubMed2005

Enhancement of brain distribution of anticancer agents using DeltaG, the 12 kDa active fragment of ZOT.

OBJECTIVE: The objective of this study was to evaluate the ability of DeltaG, the 12 kDa active fragment of ZOT, to increase the brain distribution of MTX and paclitaxel, two commonly used anticancer agents with poor distribution into the brain. METHODS: As part of dose estimation of DeltaG, [14C]-sucrose (40 microCi/kg), a hydrophilic paracellular marker, was co-administered with DeltaG (0, 400 and 800 microg/kg) with and without protease inhibitors to male Sprague-Dawley rats (n=3 per group) via an intracarotid cannula. MTX (50 mg/kg) and [3H]-paclitaxel (120 microCi/kg) were co-administered with the effective doses of DeltaG determined from the above study via the intracarotid cannula. Animals were euthanized by carbon dioxide asphyxiation at the specified time periods and brain and plasma samples were analyzed for the respective drug. RESULTS: The brain distribution of [14C]-sucrose was significantly enhanced at both doses of DeltaG. A fold enhancement in the B/P ratios of 1.88 and 2.68 was observed at the 400 and 800 microg/kg doses respectively, when the protein was protected from metabolic degradation with PIs. DeltaG significantly increased the brain distribution of MTX at each of the doses administered, with over a seven-fold increase at the 600 microg/kg dose. [3H]-paclitaxel brain AUC(0-60 min) was significantly higher in the presence of DeltaG (800 microg/kg with PIs) with a 2.5-fold enhancement in brain exposure. CONCLUSIONS: DeltaG significantly enhances the brain distribution of MTX (hydrophilic) and paclitaxel (lipophilic) and has the potential to be further developed as adjunct therapy to increase delivery of poorly permeable chemotherapeutic and other CNS targeted compounds.

Animals↗
PubMed2005

VSL#3 probiotic preparation has the capacity to hydrolyze gliadin polypeptides responsible for Celiac Sprue.

The native structure and distribution of gliadin epitopes responsible for Celiac Sprue (CS) may be influenced by cereal food processing. This work was aimed at showing the capacity of probiotic VSL#3 to decrease the toxicity of wheat flour during long-time fermentation. VSL#3 (10(9) cfu/ml) hydrolyzed completely the alpha2-gliadin-derived epitopes 62-75 and 33-mer (750 ppm). Two-dimensional electrophoresis, immunological (R5 antibody) and mass spectrometry analyses showed an almost complete degradation of gliadins during long-time fermentation of wheat flour by VSL#3. Gliadins non-hydrolyzed during fermentation by VSL#3 were subjected to peptic-tryptic (PT) digestion and analyzed by CapLC-ESI-Q-ToF-MS (Capillary Liquid Chromatography-Electrospray Ionization-Quadrupole-Time of Flight-Mass Spectrometry). Search for several epitopes showed the only presence of alpha2-gliadin-fragment 62-75 at a very low concentration (sub-ppm range). Compared to IEC-6 cells exposed to intact gliadins extracted from the chemically acidified dough (control), VSL#3 pre-digested gliadins caused a less pronounced reorganization of the intracellular F-actin which was mirrored by an attenuated effect on intestinal mucosa permeability. The release of zonulin from intestinal epithelial cells treated with gliadins was considerably lower when digested with VSL#3. Agglutination test on K 562 (S) cells showed that the PT-digest of wheat flour treated with VSL#3 increased the Minimal Agglutinating Activity of ca. 100 times. Wheat proteins were extracted from doughs and subjected to PT digestion. Compared to PT-digest from chemically acidified dough, celiac jejunal biopsies exposed to the PT-digest from the dough fermented by VSL#3 did not show an increase of the infiltration of CD3(+) intraepithelial lymphocytes. Proteolytic activity by probiotic VSL#3 may have an importance during food processing to produce pre-digested and tolerated gliadins for increasing the palatability of gluten-free products.

Actins↗
PubMed2005

Current concepts in the evaluation, diagnosis and management of acute infectious diarrhea.

Despite recent advances in our understanding of the pathogenesis of enteric diseases, acute infectious diarrhea remains a major cause of morbidity and mortality worldwide. Infection is the most common cause of acute diarrhea. Some causes of infectious diarrhea also result in serious long-term sequelae such as hemolytic uremic syndrome, Guillain-Barré syndrome and malnutrition. A better understanding of bacterial pathogenesis has grown increasingly important because of the emergence of new pathogens and the growing problems of resistance among enteric pathogens and other enteric flora. Non-antimicrobial approaches to therapy have become increasingly important with the emergence of serious antimicrobial resistance, such as vancomycin-resistant enterococcal colonization of the gastrointestinal tract. Finally, new understanding of how intestinal bacteria cause disease is revealing that enteric infections might trigger damage to epithelial cells or the intestinal barrier, or disrupt intestinal barrier and absorptive function (without necessarily causing overt diarrhea); thus, enteric infections might be far more important as emerging causes of malnutrition than has been previously appreciated. Therefore, diarrhea is both a cause and an effect of malnutrition. Treatment in most cases of bacterial and viral diseases consists of correcting fluid loss and electrolyte imbalance by oral or parenteral rehydration. Prevention of enteric illness by virtue of improved hygiene and provision of sanitation and water treatment is impractical in most developing countries, where morbidity and mortality rates are highest. For this reason, development of vaccines against the most important gastrointestinal infections remains a high priority.

Acute Disease↗
PubMed2005

Secreted autotransporter toxin produced by a diffusely adhering Escherichia coli strain causes intestinal damage in animal model assays.

Bacterial diarrheal diseases remain a major cause of morbidity and mortality in developing countries. Diffusely adhering Escherichia coli (DAEC) is a newly proposed category of diarrheagenic E. coli based on epidemiological studies. Sat, a new virulence factor of some uropathogeic Escherichia coli, was described with a vacuolating cytotoxic action in bladder and kidney tissues. In the present study, we analyzed the Sat effects, produced by a DAEC strain in rabbit ileal intestinal tissue and cultured epithelial cells. We observed enterotoxic activity in rabbit ileum tissues by Ussing chamber assays, a pronounced fluid accumulation in rabbit ileum loops with villous necrosis observed in the histopathologic examination, and morphological changes in monolayer cultures of Y1 adrenal cells. Our results suggest that DAEC strains may be involved in diarrhea.

Animals↗
PubMed2005

Role of the intestinal tight junction modulator zonulin in the pathogenesis of type I diabetes in BB diabetic-prone rats.

Increased intestinal permeability has been observed in numerous human autoimmune diseases, including type-1 diabetes (T1D) and its' animal model, the BB-wor diabetic prone rat. We have recently described zonulin, a protein that regulates intercellular tight junctions. The objective of this study was to establish whether zonulin-dependent increased intestinal permeability plays a role in the pathogenesis of T1D. In the BB diabetic-prone rat model of T1D, intestinal intraluminal zonulin levels were elevated 35-fold compared to control BB diabetic-resistant rats. Zonulin up-regulation was coincident with decreased small intestinal transepithelial electrical resistance, and was followed by the production of autoantibodies against pancreatic beta cells, which preceded the onset of clinically evident T1D by approximately 25 days. In those diabetic prone rats that did not progress to diabetes, both intraluminal zonulin and transepithelial electrical resistance were similar to those detected in diabetic-resistant animal controls. Blockade of the zonulin receptor reduced the cumulative incidence of T1D by 70%, despite the persistence of intraluminal zonulin up-regulation. Moreover, treatment responders did not seroconvert to islet cell antibodies. Combined together, these findings suggest that the zonulin-induced loss in small intestinal barrier function is involved in the pathogenesis of T1D in the BB diabetic-prone animal model.

Animals↗
PubMed2005

Celiac disease: is the atypical really typical? Summary of the recent National Institutes of Health Consensus Conference and latest advances.

Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten in genetically susceptible individuals. Gluten is a protein component in wheat and other cereals, such as rye and barley. At present, the only available treatment is a strict gluten-free diet. Recent advances have increased our understanding of the molecular basis for this disorder. The past decade has seen new scientific developments in this disease and led to the formulation of new concepts of pathophysiology and clinical manifestations. There are several targets for new treatments. This article briefly summarizes the National Institutes of Health Consensus Statement and gives an overview of new findings in recent years and of future therapeutic options for CD.

Celiac Disease↗
PubMed2005

Coeliac disease in children.

Although coeliac disease (CD) can present at any age, including the elderly, typical cases often manifest in early childhood. The clinical spectrum in children is wide and includes: (1) typical cases presenting early in life with signs of intestinal malabsorption (chronic diarrhea, weight loss, abdominal distention, etc); (2) atypical cases showing milder, often extra-intestinal, symptoms; (3) silent cases that are occasionally discovered because of serological screening; (4) potential/latent cases showing isolated positivity of coeliac serology at first testing and eventually the typical intestinal damage later in life. Many CD-associated problems, which were originally described mostly in adults, can indeed be observed in children or adolescents, e.g. reduced bone mineral density, neurological problems and associated autoimmune disorders. It is instrumental that both primary pediatricians and pediatric subspecialists have a high degree of awareness and embrace a 'liberal' use of serological CD tests in order to identify these cases in a timely fashion to prevent serious complications secondary to untreated CD.

Celiac Disease↗
PubMed2005

Dual sugar gut-permeability testing on blood drop in animal models.

BACKGROUND: Intestinal permeability is determined by measuring nonmetabolized sugars. In animals, intestinal permeability is determined in urine, using cumbersome and expensive metabolic cages. We developed an HPLC method for determining concentrations of lactulose (L) and L-rhamnose (R) in blood-drop of rabbits and mice, and we compared these results with the procedure based on sugars excreted in urine. We measured the intestinal permeability induced by a fragment (DeltaG) of the zonula occludens toxin which opens the paracellular pathway. METHODS: The animals received sugar solution and later received the same solution+DeltaG. Five-hour urine collection and timed blood tests were performed after ingestion of sugars. Sugars were measured with HPLC, and the percentage of recovered sugars was expressed as L/R ratio. RESULTS: At 60 min after administration of sugars, the mean L/R ratio for rabbits and mice was 0.026 and 0.052, respectively. At 60 min after administration of sugars+DeltaG, the mean L/R ratio for rabbits and mice was 0.22 and 0.53. The mean L/R ratio in the urine was 0.023 at basal condition and 0.25 after DeltaG ingestion. CONCLUSIONS: Testing small serum samples for sugar permeability is effective for monitoring changes in permeability of the gut in animals. This cheap simple method allows us to measure in vivo the biological activity of other molecules which modulate the paracellular pathway.

Animals↗