Tomas Koller

Prof. Tomas Koller

Comenius University in Bratislava Faculty of Medicine, Slovakia
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orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 August 2011 in European Journal of Gastroenterology & Hepatology
Verified
Journal Article
Closed access
THTibor Hlavaty
Tibor Hlavaty
MHMartin Huorka
Martin Huorka
TKTomas Koller
Tomas Koller
PZPeter Zita
Peter Zita
EKEma Kresanova
Ema Kresanova
JTJozef Toth
Jozef Toth
Patients with ulcerative colitis and Crohn's colitis have increased risk of colorectal cancer. Current screening endoscopy protocols based on white light endoscopy (WLE) and random biopsies are laborious and of uncertain sensitivity. Novel endoscopic techniques include chromoendoscopy (CE) and confocal laser endomicroscopy (CLE). The aim was to compare WLE and CE for the detection of intraepithelial neoplasia (IEN). Furthermore, we analysed the sensitivity and specificity of CE and CLE for the diagnosis of IEN. The cohort consisted of 30 patients examined by WLE, CE with 0.4% indigocarmine, and by a CLE system Pentax EC-3870CIFK during one examination. Additional 15 patients were examined by conventional protocol only. Random biopsies and biopsies from all suspicious lesions were taken. We compared the number of IENs detected by WLE and CE and analysed the predictive values of CE and CLE for the histology diagnosis. There were 1584 random biopsies (35.2 per patient) taken. There were 78 targeted biopsies (1.7 per patient) taken in 24 of 45 patients examined by WLE and an additional 36 biopsies in 16 of 30 patients examined by CE (1.17 additional per patient). There were no IENs found on random biopsies versus six low-grade or high-grade IENs in four patients (two detected by WLE, four additional by CE) from targeted biopsies, P=0.02. A total of 100 suspicious lesions were detected and analysed by CE and histology. CLE could not examine 32 of 100 lesions (two of 30 flat vs. 30 of 70 pedunculated lesions, P=0.0002, odds ratio 10.5). The sensitivity of CE/CLE for low-grade or high-grade IEN was 100/100%, the specificity 96.8/98.4%, positive predictive value was 62.5/66.7% and negative predictive value was 100/100%. Targeted biopsies are superior to random biopsies in the screening of IEN in patients with inflammatory bowel disease. CE increases the diagnostic yield of WLE. In our study CLE did not provide additional clinical benefits.

19 December 2011 in Scandinavian Journal of Gastroenterology
Verified
Journal Article
Closed access
TKTomas Koller
Tomas Koller
JKJana Kollerova
Jana Kollerova
THTibor Hlavaty
Tibor Hlavaty
MHMartin Huorka
Martin Huorka
JPJuraj Payer
Juraj Payer
Cholelithiasis and nonalcoholic fatty liver disease (NAFLD) share the same risk factors. The aim of our study was to explore the relationship between these two conditions and to indentify independent predictors of both diseases in a cohort of patients with metabolic risk factors. Consecutive patients with metabolic risk factors referred to the outpatient clinic during a one-year period were included. Cholelithiasis was defined by the presence of gallstones on abdominal ultrasound examination at inclusion or previously performed cholecystectomy. NAFLD was defined by the presence of at least one surrogate marker such as elevated alanine aminotransferase and/or gamma-glutamyl transpeptidase and/or ultrasound signs of fatty liver. Other common liver diseases were thoroughly excluded. The prevalence of cholelithiasis among patients with and without NAFLD was determined and clinical and laboratory parameters were identified as predictors of NAFLD by multivariate logistic regression. In total, 482 consecutive patients were included: mean age 61 years; 61% were women; 52% of patients had more than 2 metabolic risk factors (obesity, type 2 diabetes, hypertension, hypertriglyceridemia, or low HDL cholesterol). NAFLD and cholelithiasis were present in 41% and 34% of all patients, respectively. Significantly higher prevalence of cholelithiasis was found among patients with NAFLD compared with patients without NAFLD (47% vs. 26%, respectively; p < 0.0001). In multivariate logistic regression model, type 2 diabetes (odds ratio (OR) = 1.99), BMI above 25 kg/m2 (OR = 1.78), and cholelithiasis (OR = 1.77) were identified as independent predictors of NAFLD. Fifty six percent of patients with cholelithiasis had NAFLD compared with 33% of patients without cholelithiasis (p < 0.0001). Multivariate logistic regression identified age above 50 years (OR = 3.46), NAFLD (OR = 1.92), triglycerides above 1.7 mmol/l (OR = 1.91), BMI above 25 kg/m2 (OR = 1.84), and total cholesterol concentration (OR = 0.711) as independent predictors of cholelithiasis. In conclusion, patients with metabolic risk factors and cholelithiasis suffer significantly more often from NAFLD compared with the reference group. Cholelithiasis represents an independent risk factor of NAFLD in addition to metabolic risk factors and could be regarded as an additional risk factor of liver damage in patients with NAFLD. Furthermore, NAFLD is an independent risk factor for cholelithiasis and might represent a pathogenetic link between the metabolic syndrome and cholelithiasis.

1 April 2013 in United European Gastroenterology Journal
Verified
Journal Article
Open access
THTibor Hlavaty
Tibor Hlavaty
JTJozef Toth
Jozef Toth
TKTomas Koller
Tomas Koller
AKAnna Krajcovicova
Anna Krajcovicova
SOStanislava Oravcova
Stanislava Oravcova
MHMartin Huorka
Martin Huorka
Background: The aetiology of inflammatory bowel disease (IBD) is not known but is likely to involve a combination of genetic predisposition and environmental risk factors. Smoking has been associated consistently with a higher risk of Crohn’s disease (CD), while appendectomy and smoking appear to diminish the risk of ulcerative colitis (UC). The roles of other environmental factors are unclear. The aim of the present study was to evaluate the association of CD and UC with several environmental risk factors.Methods: This case–control study included 338 patients (190 CD, 148 UC) and 355 controls. All subjects completed a detailed questionnaire regarding breastfeeding duration, history of helminthic infections, allergic diseases, appendectomy, household size, housing type, contact with specific domestic animals, physical activity, and smoking. Associations between risk factors and CD and UC were investigated by univariate and multivariate analysis.Results: On multivariate analysis, CD associated with smoking at diagnosis (odds ratio, OR, 3.7, 95% CI 2.2–6.2; p < 0.001), being breastfed for <6 months (OR 2.7, 95% CI 1.7–4.4; p < 0.001), and less than two childhood sporting activities weekly (OR 2.7, 95% CI 1.5–5.0; p < 0.001) and inversely associated with frequent contact with cats in childhood (OR 0.6, 95% CI 0.4–0.9; p < 0.03). UC associated with less than two sporting weekly activities in childhood (OR 2.0, 95% CI 1.1–3.5, p = 0.02), fewer household members in childhood (OR 0.8, 95% CI 0.7–0.98, p = 0.03), and being breastfed for <6 months (OR 1.7, 95% CI 1.02–2.8, p = 0.04). A composite environmental risk index for CD revealed that 47 and 14% of the controls and patients with CD had no risk factors, respectively, and that 14 and 38% of the controls and patients with CD had at least two risk factors, respectively.Conclusion: CD and UC associated with infrequent childhood sports activities and short breastfeeding. Furthermore, CD associated with smoking and infrequent contact with animals in childhood. UC associated with a smaller family size in childhood.

1 January 2014 in World Journal of Gastroenterology
Verified
Journal Article
Open access
THTibor Hlavaty
Tibor Hlavaty
AKAnna Krajcovicova
Anna Krajcovicova
TKTomas Koller
Tomas Koller
JTJozef Toth
Jozef Toth
MNMonika Nevidanska
Monika Nevidanska
JPJuraj Payer
Juraj Payer
AIM: To investigate the effect of vitamin D (VD) concentrations and VD supplementation on health related quality of life in inflammatory bowel disease (IBD) patients. METHODS: A cohort of 220 IBD patients including 141 Crohn’s disease (CD) and 79 ulcerative colitis (UC) patients was followed-up at a tertiary IBD center. A subgroup of the cohort (n = 26) took VD supplements for > 3 mo. Health related quality of life was assessed using the short IBD questionnaire (sIBDQ). VD serum concentration and sIBDQ score were assessed between August and October 2012 (summer/autumn period) and between February and April 2013 (winter/spring period). The mean VD serum concentration and its correlation with disease activity of CD were determined for each season separately. In a subgroup of patients, the effects of VD supplementation on winter VD serum concentration, change in VD serum concentration from summer to winter, and winter sIBDQ score were analyzed. RESULTS: During the summer/autumn and the winter/spring period, 28% and 42% of IBD patients were VD-deficient (< 20 ng/mL), respectively. In the winter/spring period, there was a significant correlation between sIBDQ score and VD serum concentration in UC patients (r = 0.35, P = 0.02), with a trend towards significance in CD patients (r = 0.17, P = 0.06). In the winter/spring period, VD-insufficient patients (< 30 ng/mL) had a significantly lower mean sIBDQ score than VD-sufficient patients; this was true of both UC (48.3 ± 2.3 vs 56.7 ± 3.4, P = 0.04) and CD (55.7 ± 1.25 vs 60.8 ± 2.14, P = 0.04) patients. In all analyzed scenarios (UC/CD, the summer/autumn period and the winter/spring period), health related quality of life was the highest in patients with VD serum concentrations of 50-59 ng/mL. Supplementation with a median of 800 IU/d VD day did not influence VD serum concentration or the sIBDQ score. CONCLUSION: VD serum concentration correlated with health related quality of life in UC and CD patients during the winter/spring period.

1 April 2014 in European Journal of Internal Medicine
Verified
Journal Article
Closed access
ISIgor Sturdik
Igor Sturdik
MAMonika Adamcova
Monika Adamcova
JKJana Kollerova
Jana Kollerova
TKTomas Koller
Tomas Koller
ZZZuzana Zelinkova
Zuzana Zelinkova
JPJuraj Payer
Juraj Payer

6 June 2021 in World Journal of Clinical Cases
Verified
Journal Article
Open access
TKTomas Koller
Tomas Koller
PVPetra Vrbova
Petra Vrbova
IMIveta Meciarova
Iveta Meciarova
PMPavol Molcan
Pavol Molcan
MSMichal Smitka
Michal Smitka
LSLubomir Skladany
Lubomir Skladany
Muscle growth promoters are being developed for the treatment of disease-induced loss of muscle mass. Ligandrol and ostarine are selective androgen receptor modulators (SARMs) with a non-steroidal structure and a presumably more favorable side effect profile. In recent years, these substances with or without “post-cycle therapy” (PCT) are often misused by amateur athletes aiming to promote muscle growth. At the same time, reports on their toxic effects on organ systems are emerging. We report two cases of liver injury in young men who used ligandrol and/or ostarine for a few weeks followed by the use of substances for PCT. Acute liver injury occurred in both cases after stopping SARMs while on PCT. The clinical picture was dominated by jaundice and fatigue. The biochemical pattern showed a mixed type of injury with normal alkaline phosphatase and high concentrations of bilirubin and serum bile acids. Histological evidence showed predominantly cholestatic injury with canalicular bile plugs, ductopenia, and mild hepatocellular damage without significant fibrosis. The patients recovered from the condition after 3 mo. The off target effects of SARMs were likely idiosyncratic, but our report highlights the yet unrecognized effects of other toxic substances used for PCT, supra-therapeutic doses, and the complete absence of monitoring for adverse effects. Among muscle-building amateur athletes, SARMs (ligandrol or ostarine) and/or substances in PCT may cause cholestatic liver injury with prolonged recovery.