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"Siakavellas, Spyros I."
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Systematic Review with Network Meta-Analysis: Efficacy of Induction Therapy with a Second Biological Agent in Anti-TNF-Experienced Crohn’s Disease Patients
by
Siakavellas, Spyros I.
,
Pagnini, Cristiano
,
Bamias, Giorgos
in
Analysis
,
Biological products
,
Clinical trials
2018
Background and Aim. Crohn’s disease (CD) is a chronic inflammatory condition of the gastrointestinal tract with the potential to progress to a severe debilitating state. Treatment with biological agents is highly efficient, improving both short-term outcomes and long-term prognosis. Nonetheless, up to 60% of patients receiving biological therapy will exhibit nonresponse at some point. The optimal management of such patients is not clearly defined. Besides traditional anti-TNF agents (infliximab, adalimumab, and certolizumab), alternative biological therapies (natalizumab, vedolizumab, and ustekinumab) are currently available for the treatment of CD. Our aim was to analyze all available evidence regarding efficacy of a second biological in “biological-treatment-experienced” patients. Methods. A systematic review of the literature was conducted using specific criteria for selecting relevant randomized clinical trials evaluating response to administration of secondary biological therapy in “anti-TNF-experienced” CD patients. Data from these studies was used to perform (a) traditional meta-analysis to ascertain the effect of secondary treatment versus placebo and (b) network meta-analysis to compare indirectly the efficacy of available biological agents. Results. Out of initially 977 studies, only eight were included for analysis, providing a total of 1281 treated and 733 placebo-receiving CD patients. Treatment with a second biological was found to be superior to placebo for both induction of remission (OR 2.2, 95% CI 1.7 to 3) and response (OR 1.9, 95% CI 1.5 to 2.5), with global rates of 24% and 42%, respectively (placebo rate: 11% and 27%, p<0.0001 for both). Indirect comparisons performed with network meta-analysis suggest no specific agent is clearly superior to others, with relatively better results observed for adalimumab in inducing disease remission. Conclusion. In anti-TNF-experienced CD patients, secondary biological administration may be efficient, while no specific agent seems to outperform the others. Further research is needed to identify optimal management strategies for this challenging subset of patients.
Journal Article
Tumor Necrosis Factor–like Cytokine TL1A and Its Receptors DR3 and DcR3
by
Siakavellas, Spyros I.
,
Bamias, Giorgos
in
Animals
,
CD4-Positive T-Lymphocytes - metabolism
,
Cytokines
2015
Tumor necrosis factor (TNF)-like cytokine 1A (TL1A) is a member of the TNF superfamily of proteins (TNFSF15), which signals through association with death domain receptor 3 (DR3). Decoy receptor 3 (DcR3) competes with DR3 for TL1A binding and inhibits functional signaling. These proteins are significantly upregulated in inflamed intestinal tissues, and their pathogenetic importance for inflammatory bowel disease (IBD) is suggested by accumulating evidence. TL1A/DR3 induce costimulatory signals to activated lymphocytes, including the gut-specific populations of CD4+CD161+ and CD4+CCR9+ cells, affecting all major effector pathways and inducing the mucosal upregulation of Th1, Th2, and Th17 factors. They may also participate in mucosal homeostasis and defense against pathogens through their effects on the development and function of the recently described innate lymphoid cells. T-regulatory lymphocytes highly express DR3, and they respond to TL1A stimulation also. Mechanistic studies by transgenic expression of TL1A, deletion of TL1A or DR3, and therapeutic blockade by anti-TL1A antibodies all support the critical involvement of the corresponding pathways in the pathogenesis of chronic mucosal inflammation. Wide genome association studies have identified IBD-specific polymorphisms in TNFSF15 gene, which have functional implications and serve as poor prognostic factors. Recently, TL1A blockade in mice was presented as a unique pharmacological treatment for the reversal of established intestinal fibrosis. Finally, TL1A/DR3 signaling seems to critically participate in extraintestinal inflammatory conditions that are frequently associated with IBD as part of the gut-joint-skin-eye axis. These converging lines of evidence make TL1A/DR3 a suitable model for personalized approaches to IBD therapy.
Journal Article
Inflammatory Bowel Disease (IBD)-Associated Colorectal Cancer (CRC): Is cGAS-STING Pathway Targeting the Key to Chemoprevention?
by
Michailidou, Elisavet
,
Siakavellas, Spyros I.
,
Papadakos, Stavros P.
in
Animals
,
Cancer
,
Cancer therapies
2025
Inflammatory bowel disease (IBD)-associated colorectal cancer (CRC) remains a significant clinical challenge due to its link with chronic inflammation and the inherent limitations of current prevention and surveillance strategies. The cGAS-STING pathway has emerged as a key player in the immune regulation of inflammation-driven carcinogenesis, demonstrating both protective and pathogenic roles. This review examines the contrasting roles of the cGAS-STING signaling pathway in intestinal inflammation and colitis-associated cancer (CAC), emphasizing its promise as a target for cancer prevention strategies. Evidence suggests that modulating this pathway could preserve epithelial integrity, limit chronic inflammation, and bolster anti-tumor immunity. Despite advancements in therapies like mesalazine and surveillance colonoscopy programs, gaps in efficacy remain, particularly for Crohn’s disease and high-risk populations. Future research should focus on integrating cGAS-STING-targeted approaches with existing modalities to provide personalized and less invasive strategies for CAC prevention. By harnessing this pathway’s therapeutic potential, a paradigm shift in managing IBD-associated CRC may be achieved, addressing the challenges of long-term disease surveillance and prevention.
Journal Article
Exploring the Role of GITR/GITRL Signaling: From Liver Disease to Hepatocellular Carcinoma
by
Koufakis, Theocharis
,
Reppas, Lampros
,
Siakavellas, Spyros I.
in
Amino acids
,
Antigens
,
Apoptosis
2024
Hepatocellular carcinoma (HCC) is the most common primary liver cancer and presents a continuously growing incidence and high mortality rates worldwide. Besides advances in diagnosis and promising results of pre-clinical studies, established curative therapeutic options for HCC are not currently available. Recent progress in understanding the tumor microenvironment (TME) interactions has turned the scientific interest to immunotherapy, revolutionizing the treatment of patients with advanced HCC. However, the limited number of HCC patients who benefit from current immunotherapeutic options creates the need to explore novel targets associated with improved patient response rates and potentially establish them as a part of novel combinatorial treatment options. Glucocorticoid-induced TNFR-related protein (GITR) belongs to the TNFR superfamily (TNFRSF) and promotes CD8+ and CD4+ effector T-cell function with simultaneous inhibition of Tregs function, when activated by its ligand, GITRL. GITR is currently considered a potential immunotherapy target in various kinds of neoplasms, especially with the concomitant use of programmed cell-death protein-1 (PD-1) blockade. Regarding liver disease, a high GITR expression in liver progenitor cells has been observed, associated with impaired hepatocyte differentiation, and decreased progenitor cell-mediated liver regeneration. Considering real-world data proving its anti-tumor effect and recently published evidence in pre-clinical models proving its involvement in pre-cancerous liver disease, the idea of its inclusion in HCC therapeutic options theoretically arises. In this review, we aim to summarize the current evidence supporting targeting GITR/GITRL signaling as a potential treatment strategy for advanced HCC.
Journal Article
Predictors of Response to Vedolizumab in Patients with Ulcerative Colitis: Results from the Greek VEDO-IBD Cohort
2022
BackgroundOptimization of treatment with biologics is currently an unmet need for patients with ulcerative colitis (UC). Real-world studies provide neutral estimates of drug efficacy and safety within unselected patient populations and allow for the recognition of specific characteristics that affect response to therapy.AimsWe aimed to depict the efficacy of vedolizumab in patients with UC in a real-world setting and identify prognosticators of improved outcomes.MethodsPatients with active UC who commenced treatment with vedolizumab were prospectively followed up. Patient-reported outcomes (PROs) and clinical/endoscopic-reported outcomes were recorded at baseline and at weeks 14 and 54. Predefined endpoints of early and persistent efficacy were analyzed against clinical characteristics to identify prognostic factors for response.ResultsWe included 96 patients (anti-TNF-exposed = 38.5%). At week 14, 73 patients (76%) had clinical response and 54 (56.3%) clinical remission. At week 54, the primary endpoint of vedolizumab persistence was met by 72 patients (75%), whereas steroid-free clinical remission by 59.4%. Among patients who had endoscopy, rates for mucosal healing (Mayo endoscopic score of 0) were 29.8% at week 14 and 44.6% at week 54, respectively. Vedolizumab treatment led to significant improvements in quality of life. Corticosteroid-refractory or anti-TNF-refractory disease, articular manifestations, and high baseline UC-PRO2 were associated with decreased efficacy of vedolizumab in the primary and secondary outcomes.ConclusionsVedolizumab is characterized by high efficacy and long-term treatment persistence in UC. More aggressive disease, as indicated by refractoriness to steroids or anti-TNFs and elevated baseline PROs, may predict suboptimal response and help pre-treatment prognostic stratification of patients.
Journal Article
Elevated Serum Levels of the Antiapoptotic Protein Decoy-Receptor 3 Are Associated with Advanced Liver Disease
by
Siakavellas, Spyros I.
,
Ladas, Spiros D.
,
Koutsounas, Ioannis
in
Biopsy
,
Hepatitis
,
Hospitals
2016
Background. Decoy-receptor 3 (DcR3) exerts antiapoptotic and immunomodulatory function and is overexpressed in neoplastic and inflammatory conditions. Serum DcR3 (sDcR3) levels during the chronic hepatitis/cirrhosis/hepatocellular carcinoma (HCC) sequence have not been explored. Objective. To assess the levels and significance of sDcR3 protein in various stages of chronic liver disease. Methods. We compared sDcR3 levels between healthy controls and patients with chronic viral hepatitis (CVH), decompensated cirrhosis (DC), and HCC. Correlations between sDcR3 levels and various patient- and disease-related factors were analyzed. Results. sDcR3 levels were significantly higher in patients with CVH than in controls (P<0.01). sDcR3 levels were elevated in DC and HCC, being significantly higher compared not only to controls (P<0.001 for both) but to CVH patients as well (P<0.001 for both). In addition, DcR3 protein was detected in large quantities in the ascitic fluid of cirrhotics. In patients with CVH, sDcR3 significantly correlated to fibrosis severity, as estimated by Ishak score (P=0.019) or by liver stiffness measured with elastography (Spearman r=0.698, P<0.001). In cirrhotic patients, significant positive correlations were observed between sDcR3 levels and markers of severity of hepatic impairment, including MELD score (r=0.653, P<0.001). Conclusions. Circulating levels of DcR3 are elevated during chronic liver disease and correlate with severity of liver damage. sDcR3 may serve as marker for liver fibrosis severity and progression to end-stage liver disease.
Journal Article
Recent advances in the diagnosis and management of amoebiasis
2025
With increasing international travel and migration, tropical and infectious diseases once largely confined to specialist institutes now present more widely. Amoebiasis is a potentially dangerous example since it may closely mimic the presentation of inflammatory bowel disease. Misdiagnosis and treatment with immunosuppressants can result in fulminant amoebiasis and death. This review considers the epidemiology, pathogenesis, clinical features, diagnosis and treatment of intestinal and extraintestinal amoebiasis. It is written primarily for gastroenterologists, surgeons and acute physicians.
Journal Article
Tumor Necrosis Factor–like Cytokine TL1A and Its Receptors DR3 and DcR3
2015
Tumor necrosis factor (TNF)-like cytokine 1A (TL1A) is a member of the TNF superfamily of proteins (TNFSF15), which signals through association with death domain receptor 3 (DR3). Decoy receptor 3 (DcR3) competes with DR3 for TL1A binding and inhibits functional signaling. These proteins are significantly upregulated in inflamed intestinal tissues, and their pathogenetic importance for inflammatory bowel disease (IBD) is suggested by accumulating evidence. TL1A/DR3 induce costimulatory signals to activated lymphocytes, including the gut-specific populations of CD4+CD161+ and CD4+CCR9+ cells, affecting all major effector pathways and inducing the mucosal upregulation of Th1, Th2, and Th17 factors. They may also participate in mucosal homeostasis and defense against pathogens through their effects on the development and function of the recently described innate lymphoid cells. T-regulatory lymphocytes highly express DR3, and they respond to TL1A stimulation also. Mechanistic studies by transgenic expression of TL1A, deletion of TL1A or DR3, and therapeutic blockade by anti-TL1A antibodies all support the critical involvement of the corresponding pathways in the pathogenesis of chronic mucosal inflammation. Wide genome association studies have identified IBD-specific polymorphisms in TNFSF15 gene, which have functional implications and serve as poor prognostic factors. Recently, TL1A blockade in mice was presented as a unique pharmacological treatment for the reversal of established intestinal fibrosis. Finally, TL1A/DR3 signaling seems to critically participate in extraintestinal inflammatory conditions that are frequently associated with IBD as part of the gut–joint–skin–eye axis. These converging lines of evidence make TL1A/DR3 a suitable model for personalized approaches to IBD therapy.
Journal Article
Comparative Study of Candidate Housekeeping Genes for Quantification of Target Gene Messenger RNA Expression by Real-Time PCR in Patients with Inflammatory Bowel Disease
by
Siakavellas, Spyros I.
,
Ladas, Spiros D.
,
Balla, Iliana G.
in
Case-Control Studies
,
Gene expression
,
Genes, Essential - genetics
2013
Mucosal expression of immunological mediators is modified in inflammatory bowel disease (IBD). Quantification of target gene messenger RNA (mRNA) transcripts depends on the normalization to a housekeeping or reference gene. Stability of housekeeping gene expression is critical for the accurate measurement of transcripts of the target gene. No studies have addressed the optimization of reference gene performance for mRNA studies in healthy intestinal mucosa and during mucosal inflammation.MethodsRNA was extracted from endoscopically obtained intestinal biopsies from healthy control subjects and patients with active IBD or non-IBD inflammatory diseases. Comparative analysis of 10 candidate housekeeping genes for quantitative real-time PCR was carried out according to predefined criteria, including use of the Web-based RefFinder platform.ResultsWe demonstrate that intestinal inflammation may significantly affect the stability of mucosal expression of housekeeping genes. Commonly used controls, such as glyceraldehyde-3-phosphate dehydrogenase, β-actin, or β2-microglobulin displayed high variability within the control group and/or between the healthy and inflamed mucosae. In contrast, we have identified novel genes with optimal stability, which may be used as appropriate housekeeping controls. The ribosomal proteins encoding genes (RPLPO and RPS9) were the most stable because their expression was not affected by interindividual differences, the presence of inflammation, or intestinal location. Normalization ofthe mRNA expression of mucosal tumor necrosis factor-α was highly dependent on the specific reference gene and varied significantly when normalized to genes with high or low stability.ConclusionsValidation for optimal performance of the housekeeping gene is required for target mRNA quantification in healthy intestine and IBD-associated lesions. Suboptimal reference gene expression may explain conflicting results from published studies on IBD gene expression.
Journal Article
Changing Pattern in the Clinical Presentation of Pediatric Celiac Disease: A 30-Year Study
by
Panayiotou, Joanna
,
Krini, Maro
,
Roma, Eleftheria
in
Adolescent
,
Celiac disease
,
Celiac Disease - complications
2009
Background/Aims: The incidence of celiac disease (CD) has increased in recent years due to the recognition of atypical forms and the identification of silent cases through serological screening. Our aim was to detect temporal trends in the presentation of pediatric CD in Greece. Methods: We reviewed the medical files of all children diagnosed with CD between 1978 and 2007 at a single academic pediatric center. Cases were classified according to the year of diagnosis. We examined demographic data, presenting symptoms, delay to diagnosis, and the prevalence of associated conditions. Results: During the study period, 284 new cases of CD were diagnosed. The incidence of CD was significantly increased in recent years (p < 0.05). We observed significant trends towards older age at diagnosis (p < 0.001), longer delay to diagnosis (p < 0.05) and decreased frequency of the classical and/or gastrointestinal predominant mode of presentation (p < 0.001). In recent years, diagnosis of CD was significantly more frequent due to testing of asymptomatic children with a positive family history for CD or personal history of associated conditions (p < 0.001). Conclusion: We report a changing pattern in the presentation of pediatric CD in Greece. CD is diagnosed more frequently in older children, oftentimes presents with atypical symptoms, and is increasingly detected through serological screening. CD should be considered in the presence of atypical presentations.
Journal Article