Amir Tirosh

Dr. Amir Tirosh

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Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

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

Representative Publications

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7 April 2011 in New England Journal of Medicine
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ATAmir Tirosh
Amir Tirosh
ISIris Shai
Iris Shai
AAArnon Afek
Arnon Afek
GDGal Dubnov-Raz
Gal Dubnov-Raz
NANir Ayalon
Nir Ayalon
ARAssaf Rudich
Assaf Rudich
The association of body-mass index (BMI) from adolescence to adulthood with obesity-related diseases in young adults has not been completely delineated. We conducted a prospective study in which we followed 37,674 apparently healthy young men for incident angiography-proven coronary heart disease and diabetes through the Staff Periodic Examination Center of the Israeli Army Medical Corps. The height and weight of participants were measured at regular intervals, with the first measurements taken when they were 17 years of age. During approximately 650,000 person-years of follow-up (mean follow-up, 17.4 years), we documented 1173 incident cases of type 2 diabetes and 327 of coronary heart disease. In multivariate models adjusted for age, family history, blood pressure, lifestyle factors, and biomarkers in blood, elevated adolescent BMI (the weight in kilograms divided by the square of the height in meters; mean range for the first through last deciles, 17.3 to 27.6) was a significant predictor of both diabetes (hazard ratio for the highest vs. the lowest decile, 2.76; 95% confidence interval [CI], 2.11 to 3.58) and angiography-proven coronary heart disease (hazard ratio, 5.43; 95% CI, 2.77 to 10.62). Further adjustment for BMI at adulthood completely ablated the association of adolescent BMI with diabetes (hazard ratio, 1.01; 95% CI, 0.75 to 1.37) but not the association with coronary heart disease (hazard ratio, 6.85; 95% CI, 3.30 to 14.21). After adjustment of the BMI values as continuous variables in multivariate models, only elevated BMI in adulthood was significantly associated with diabetes (β=1.115, P=0.003; P=0.89 for interaction). In contrast, elevated BMI in both adolescence (β=1.355, P=0.004) and adulthood (β=1.207, P=0.03) were independently associated with angiography-proven coronary heart disease (P=0.048 for interaction). An elevated BMI in adolescence — one that is well within the range currently considered to be normal — constitutes a substantial risk factor for obesity-related disorders in midlife. Although the risk of diabetes is mainly associated with increased BMI close to the time of diagnosis, the risk of coronary heart disease is associated with an elevated BMI both in adolescence and in adulthood, supporting the hypothesis that the processes causing incident coronary heart disease, particularly atherosclerosis, are more gradual than those resulting in incident diabetes. (Funded by the Chaim Sheba Medical Center and the Israel Defense Forces Medical Corps.)

6 October 2005 in New England Journal of Medicine
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ATAmir Tirosh
Amir Tirosh
ISIris Shai
Iris Shai
DTDorit Tekes-Manova
Dorit Tekes-Manova
EIEran Israeli
Eran Israeli
DPDavid Pereg
David Pereg
IGIsraeli Diabetes Research Group
Israeli Diabetes Research Group
The normal fasting plasma glucose level was recently defined as less than 100 mg per deciliter (5.55 mmol per liter). Whether higher fasting plasma glucose levels within this range independently predict type 2 diabetes in young adults is unclear.

1 July 2019 in The Lancet Diabetes & Endocrinology
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Journal Article
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OMOfri Mosenzon
Ofri Mosenzon
TBThalia Marie Blicher
Thalia Marie Blicher
SRSigne Rosenlund
Signe Rosenlund
JEJan W Eriksson
Jan W Eriksson
SHSimon Heller
Simon Heller
EZE Zhdanova
E Zhdanova
Oral semaglutide is the first oral glucagon-like peptide-1 (GLP-1) receptor agonist for glycaemic control in patients with type 2 diabetes. Type 2 diabetes is commonly associated with renal impairment, restricting treatment options. We aimed to investigate the efficacy and safety of oral semaglutide in patients with type 2 diabetes and moderate renal impairment. This randomised, double-blind, phase 3a trial was undertaken at 88 sites in eight countries. Patients aged 18 years and older, with type 2 diabetes, an estimated glomerular filtration rate of 30-59 mL/min per 1·73 m2, and who had been receiving a stable dose of metformin or sulfonylurea, or both, or basal insulin with or without metformin for the past 90 days were eligible. Participants were randomly assigned (1:1) by use of an interactive web-response system, with stratification by glucose-lowering medication and renal function, to receive oral semaglutide (dose escalated to 14 mg once daily) or matching placebo for 26 weeks, in addition to background medication. Participants and site staff were masked to assignment. Two efficacy-related estimands were defined: treatment policy (regardless of treatment discontinuation or rescue medication) and trial product (on treatment without rescue medication) in all participants randomly assigned. Endpoints were change from baseline to week 26 in HbA1c (primary endpoint) and bodyweight (confirmatory secondary endpoint), assessed in all participants with sufficient data. Safety was assessed in all participants who received at least one dose of study drug. This trial is registered on ClinicalTrials.gov, number NCT02827708, and the European Clinical Trials Registry, number EudraCT 2015-005326-19, and is now complete. Between Sept 20, 2016, and Sept 29, 2017, of 721 patients screened, 324 were eligible and randomly assigned to oral semaglutide (n=163) or placebo (n=161). Mean age at baseline was 70 years (SD 8), and 168 (52%) of participants were female. 133 (82%) participants in the oral semaglutide group and 141 (88%) in the placebo group completed 26 weeks on treatment. At 26 weeks, oral semaglutide was superior to placebo in decreasing HbA1c (estimated mean change of -1·0 percentage point (SE 0·1; -11 mmol/mol [SE 0·8]) vs -0·2 percentage points (SE 0·1; -2 mmol/mol [SE 0·8]); estimated treatment difference [ETD]: -0·8 percentage points, 95% CI -1·0 to -0·6; p<0·0001) and bodyweight (estimated mean change of -3·4 kg [SE 0·3] vs -0·9 kg [SE 0·3]; ETD, -2·5, 95% CI -3·2 to -1·8; p<0·0001) by the treatment policy estimand. Significant differences were seen for the trial product estimand: mean change in HbA1c -1·1 percentage points (SE 0·1; -12 mmol/mol [SE 0·8] versus -0·1 percentage points (SE 0·1; -1 mmol/mol [SE 0·8]; ETD -1·0 percentage points, 95% CI -1·2 to -0·8; p<0·0001); mean change in bodyweight -3·7 kg (SE 0·3) versus -1·1 kg (SE 0·3; ETD -2·7 kg, 95% CI -3·5 to -1·9; p<0·0001). More patients taking oral semaglutide than placebo had adverse events (120 [74%] of 163 vs 105 [65%] of 161), and discontinued treatment as a result (24 [15%] vs eight [5%]). Gastrointestinal events, mainly mild-to-moderate nausea, were more common with oral semaglutide than with placebo. Three deaths occurred during the treatment period that were not condsidered to be treatment related, one in the semaglutide group and two in the placebo group. Oral semaglutide was effective in patients with type 2 diabetes and moderate renal impairment, potentially providing a new treatment option for this population. Safety, including renal safety, was consistent with the GLP-1 receptor agonist class. Novo Nordisk A/S.

26 November 2012 in Archives of internal medicine (1960)
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AVAsaf Vivante
Asaf Vivante
EGEliezer Golan
Eliezer Golan
DTDorit Tzur
Dorit Tzur
ALAdi Leiba
Adi Leiba
ATAmir Tirosh
Amir Tirosh
RCRonit Calderon-Margalit
Ronit Calderon-Margalit
Obesity is a global health problem.1,2 The high prevalence of overweight and obesity among children, adolescents, and adults is of great concern. Since 1980, the prevalence of obesity has tripled among US school-age children and adolescents, and it has remained high, at approximately 17%, from 1999 to the present.3-6 Children and adolescents with high body mass index (BMI) often become obese adults,7,8 and obese adults are at risk for many chronic conditions such as diabetes, which confers a future risk for chronic kidney disease (CKD) and end-stage renal disease (ESRD). The relationship between obesity and CKD is complex and not yet fully understood. Few studies9-12 have examined the relationship between excess weight and risk for all-cause ESRD; although an association between BMI and ESRD in general has been documented, these studies did not determine whether such an association is limited to diabetic ESRD. In addition, previous investigations of the association between obesity and CKD or ESRD were conducted only among adults. It remains unclear whether a history of overweight and obesity during childhood or adolescence poses an additional risk.

24 April 2019 in Science Translational Medicine
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ATAmir Tirosh
Amir Tirosh
ECEdiz S. Calay
Ediz S. Calay
GTGurol Tuncman
Gurol Tuncman
KCKathryn C. Claiborn
Kathryn C. Claiborn
KIKaren E. Inouye
Karen E. Inouye
GHGökhan S. Hotamisligil
Gökhan S. Hotamisligil
The short-chain fatty acid propionate is a potent inhibitor of molds that is widely used as a food preservative and endogenously produced by gut microbiota. Although generally recognized as safe by the U.S. Food and Drug Administration, the metabolic effects of propionate consumption in humans are unclear. Here, we report that propionate stimulates glycogenolysis and hyperglycemia in mice by increasing plasma concentrations of glucagon and fatty acid–binding protein 4 (FABP4). Fabp4-deficient mice and mice lacking liver glucagon receptor were protected from the effects of propionate. Although propionate did not directly promote glucagon or FABP4 secretion in ex vivo rodent pancreatic islets and adipose tissue models, respectively, it activated the sympathetic nervous system in mice, leading to secretion of these hormones in vivo. This effect could be blocked by the pharmacological inhibition of norepinephrine, which prevented propionate-induced hyperglycemia in mice. In a randomized, double-blind, placebo-controlled study in humans, consumption of a propionate-containing mixed meal resulted in a postprandial increase in plasma glucagon, FABP4, and norepinephrine, leading to insulin resistance and compensatory hyperinsulinemia. Chronic exposure of mice to a propionate dose equivalent to that used for food preservation resulted in gradual weight gain. In humans, plasma propionate decreased with weight loss in the Dietary Intervention Randomized Controlled Trial (DIRECT) and served as an independent predictor of improved insulin sensitivity. Thus, propionate may activate a catecholamine-mediated increase in insulin counter-regulatory signals, leading to insulin resistance and hyperinsulinemia, which, over time, may promote adiposity and metabolic abnormalities. Further evaluation of the metabolic consequences of propionate consumption is warranted.

1 April 1999 in Journal of Biological Chemistry
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Journal Article
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ATAmir Tirosh
Amir Tirosh
RPRuth Potashnik
Ruth Potashnik
NBNava Bashan
Nava Bashan
ARAssaf Rudich
Assaf Rudich
In a recent study we have demonstrated that 3T3-L1 adipocytes exposed to low micromolar H2O2 concentrations display impaired insulin stimulated GLUT4 translocation from internal membrane pools to the plasma membrane (Rudich, A., Tirosh, A., Potashnik, R., Hemi, R., Kannety, H., and Bashan, N. (1998) Diabetes 47, 1562–1569). In this study we further characterize the cellular mechanisms responsible for this observation. Two-hour exposure to ∼25 μm H2O2 (generated by adding glucose oxidase to the medium) resulted in disruption of the normal insulin stimulated insulin receptor substrate (IRS)-1 and phosphatidylinositol (PI) 3-kinase cellular redistribution between the cytosol and an internal membrane pool (low density microsomal fraction (LDM)). This was associated with reduced insulin-stimulated IRS-1 and p85-associated PI 3-kinase activities in the LDM (84 and 96% inhibition, respectively). The effect of this finding on the downstream insulin signal was demonstrated by a 90% reduction in insulin stimulated protein kinase B (PKB) serine 473 phosphorylation and impaired activation of PKBα and PKBγ. Both control and oxidized cells exposed to heat shock displayed a wortmannin insensitive PKB serine phosphorylation and activity. These data suggest that activation of PKB and GLUT4 translocation are insulin signaling events dependent upon a normal insulin induced cellular compartmentalization of PI 3-kinase and IRS-1, which is oxidative stress-sensitive. These findings represent a novel cellular mechanism for the induction of insulin resistance in response to changes in the extracellular environment.