Konstantinos Spengos

Eginition Hospital Athens, Athínai, Attica, Greece

Are you Konstantinos Spengos?

Claim your profile

Publications (165)474.44 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Muscle Lim Protein (MLP) has emerged as a critical regulator of striated muscle physiology and pathophysiology. Mutations in cysteine and glycine-rich protein 3 (CSRP3), the gene encoding MLP, have been directly associated with human cardiomyopathies, while aberrant expression patterns are reported in human cardiac and skeletal muscle diseases. Increasing evidence suggests that MLP has an important role in both myogenic differentiation and myocyte cytoarchitecture, although the full spectrum of its intracellular roles has not been delineated. We report the discovery of an alternative splice variant of MLP, designated as MLP-b, showing distinct expression in neuromuscular disease and direct roles in actin dynamics and muscle differentiation. This novel isoform originates by alternative splicing of exons 3 and 4. At the protein level, it contains the N-terminus first half LIM domain of MLP and a unique sequence of 22 amino acids. Physiologically it is expressed during early differentiation, whereas its overexpression reduces C2C12 differentiation and myotube formation. This may be mediated through its inhibition of MLP/CFL2-mediated F-actin dynamics. In differentiated striated muscles, MLP-b localizes to the sarcomeres and binds directly to Z-disc components including α-actinin, T-cap and MLP. Our findings unveil a novel player in muscle physiology and pathophysiology that is implicated in myogenesis as a negative regulator of myotube formation, and in differentiated striated muscles as a contributor to sarcomeric integrity. This article is protected by copyright. All rights reserved.
    FEBS Journal 05/2014; · 4.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Apolipropotein E(apoE) is a plasma protein exhibiting three common isoforms (E2, E3, E4). Its involvement in lipoprotein metabolism may have an impact on stroke occurrence. As results in the literature are inconclusive further studies are needed to elucidate its role. Our objective was to study the role of apoE isoforms and the interplay with environmental risk factors in patients with first ischaemic stroke occurrence in the Greek population. Three hundred and twenty-nine patients with first-ever ischaemic stroke were included in our study. Strokes of cardioembolic origin and patients with autoimmune or prothrombotic syndromes were excluded. A control group of 361 subjects with no stroke history were also included in our study. Risk factors (hyperlipidemia, hypertension, diabetes mellitus and smoking) were assessed. ApoE alleles were determined in all subjects participating in the study. Genotype ε3/ε3 was found to have a protective role against stroke occurrence compared with other genotypes (odds ratio 0.674, 95% confidence interval 0.480-0.946) especially in the female patient subgroup. In multivariate analysis after adjustment for age, body mass index (BMI), hypertension, dyslipidemia, diabetes mellitus and smoking, the role of genotype was limited and outweighed by risk factors in both genders. No association between apoE alleles and BMI, cholesterol, triglycerides or high-density lipoprotein plasma levels was noted. Our study was indicative of a protective role of the ε3/ε3 genotype, especially in female patients. However, risk factors such as age, BMI, hypertension, dyslipidemia, diabetes mellitus and smoking have a strong impact on stroke occurrence and outweigh the protective role of the ε3/ε3 genotype.
    European Journal of Neurology 01/2014; · 4.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the study was to investigate the effects of power training with light vs. heavy loads during the tapering phases of a double periodized training year on track and field throwing performance. Thirteen track and field throwers aged 16-26 years followed 8 months of systematic training for performance enhancement aiming at two tapering phases during the winter and the spring competition periods. Athletes performed tapering with two different resistance training loads (counterbalanced design): 7 athletes used 30%-1RM (LT) and 6 athletes used the 85%-1RM (HT), during the winter tapering. The opposite was performed at the spring tapering. Before and after each tapering, throwing performance, 1-RM strength, vertical jumping, rate of force development (RFD), vastus lateralis architecture, and rate of perceived exertion (RPE) were evaluated. Throwing performance increased significantly by 4.8 ± 1.0% and 5.6 ± 0.9% after LT and HT, respectively. Leg press 1-RM and squat jump power increased more after HT than LT (5.9 ± 3.2% vs. -3.4 ± 2.5%, and 5.1 ± 2.4% vs. 0.9 ± 1.4% respectively, p < 0.05). Leg press RFD increased more in HT (38.1 ± 16.5%) compared to LT (-2.9 ± 6.7%), but LT induced less fatigue than HT (4.0 ± 1.5 vs. 6.7 ± 0.9, p < 0.05). Muscle architecture was not altered after either program. These results suggest that performance increases similarly after tapering with LT or HT in track and field throwers but HT leads to greater increases in strength, whole body power and RFD.
    3rd Congress of Biochemistry and Exercise Physiology of Hellenic Society of Biochemistry and Physiology of Exercise, Athens, Greece; 11/2013
  • 3rd Congress of Biochemistry and Exercise Physiology of Hellenic Society of Biochemistry and Physiology of Exercise, Athens, Greece; 11/2013
  • 3rd Congress of Biochemistry and Exercise Physiology of Hellenic Society of Biochemistry and Physiology of Exercise, Athens, Greece; 11/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: Risk factors for IS in young adults differ between genders and evolve with age, but data on the age- and gender-specific differences by stroke etiology are scare. These features were compared based on individual patient data from 15 European stroke centers. Stroke etiology was reported in detail for 3331 patients aged 15-49 years with first-ever IS according to Trial of Org in Acute Stroke Treatment (TOAST) criteria: large-artery atherosclerosis (LAA), cardioembolism (CE), small-vessel occlusion (SVO), other determined etiology, or undetermined etiology. CE was categorized into low- and high-risk sources. Other determined group was divided into dissection and other non-dissection causes. Comparisons were done using logistic regression, adjusting for age, gender, and center heterogeneity. Etiology remained undetermined in 39.6%. Other determined etiology was found in 21.6%, CE in 17.3%, SVO in 12.2%, and LAA in 9.3%. Other determined etiology was more common in females and younger patients, with cervical artery dissection being the single most common etiology (12.8%). CE was more common in younger patients. Within CE, the most frequent high-risk sources were atrial fibrillation/flutter (15.1%) and cardiomyopathy (11.5%). LAA, high-risk sources of CE, and SVO were more common in males. LAA and SVO showed an increasing frequency with age. No significant etiologic distribution differences were found amongst southern, central, or northern Europe. The etiology of IS in young adults has clear gender-specific patterns that change with age. A notable portion of these patients remains without an evident stroke mechanism according to TOAST criteria.
    European Journal of Neurology 07/2013; · 4.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND PURPOSE: Ankle-brachial blood pressure index (ABI) is a clinical tool to identify the presence of peripheral artery disease. There is a scarcity of data associating ABI with long-term outcome in patients with IS. The association between ABI and long-term outcome in patients with first-ever acute IS was assessed. METHODS: Ankle-brachial blood pressure index was assessed in all consecutive patients with a first-ever acute IS admitted at Alexandra University hospital (Athens, Greece) between January 2005 and December 2010. ABI was considered normal when > 0.90 and ≤ 1.30. The Kaplan-Meier product limit method was used to estimate the probability of 5-year composite cardiovascular event-free (defined as recurrent stroke, myocardial infarction or cardiovascular death) and overall survival. A multivariate analysis was performed to assess whether ABI is an independent predictor of 5-year mortality and dependence. RESULTS: Amongst 653 patients, 129 (19.8%) with ABI ≤ 0.9 were identified. Five-year cumulative composite cardiovascular event-free and overall survival rates were better in normal ABI stroke patients (log-rank test: 7.22, P = 0.007 and 23.40, P < 0.001, respectively). There was no difference in 5-year risk of stroke recurrence between low and normal ABI groups (hazard ratio, HR = 1.23, 95%CI 0.68-2.23). In multivariate Cox regression analysis, independent predictors of 5-year mortality included age (HR = 2.55 per 10 years, 95%CI 1.86-3.48, P < 0.001), the National Institutes of Health Stroke Scale (per point increase HR = 1.12, 95%CI 1.08-1.16, P < 0.001), and low ABI (HR = 2.22, 95%CI 1.22-4.03, P = 0.009). Age (HR = 1.21 per 10 years, 95%CI 1.01-1.45, P = 0.04) and low ABI (HR = 1.72, 95%CI 1.11-2.67, P = 0.01) were independent predictors of the composite cardiovascular end-point. CONCLUSIONS: Low ABI in patients with acute IS is associated with increased 5-year cardiovascular event risk and mortality. However, ABI does not appear to predict long-term stroke recurrence.
    European Journal of Neurology 06/2013; · 4.16 Impact Factor
  • Georgios Koutsis, Gerasimos Siasos, Konstantinos Spengos
    [Show abstract] [Hide abstract]
    ABSTRACT: MicroRNAs (miRNAs) are small non-coding RNAs approximately 22 nucleotides in length that play a pivotal role in post-transcriptional gene regulation by binding to complementary sites in the 3'-untranslated region of messenger RNAs. In the past decade, their role in several human diseases, from cancer to cardiovascular disease, has been established by a wealth of evidence. Stroke is responsible for 10% of deaths worldwide and is one of the leading causes of disability. MiRNAs are involved in stroke risk factors including hypertension, atherosclerosis, atrial fibrillation, diabetes and dyslipidemia. The role of miRNAs in the pathophysiology of stroke has been the subject of more recent investigations. Animal studies, which dominate the field, have demonstrated the differential expression of miRNAs in brain and blood following ischemic or hemorrhagic insult and the potential use of miRNA antagonists to reduce focal cerebral damage. In particular, antagomirs to miR-145, -497, -181a, -1 and let-7f have been found to be neuroprotective in vivo. The discovery of circulating miRNAs in peripheral blood, which are unexpectedly stable, has allowed the recent completion of several studies in human stroke patients that have confirmed the differential expression of specific miRNAs following stroke and have addressed their potential use as diagnostic and prognostic markers. With miRNA research in stroke still in its infancy, it is anticipated that in the next few years significant discoveries that may have important therapeutic implications will emerge.
    Current topics in medicinal chemistry 05/2013; · 4.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: To evaluate the effect of a combination of eccentric and ballistic strength training program on muscle fiber composition and fiber cross-sectional area. METHODS: Eight male university students (age: 21±2 yrs, height: 177±5 cm, body mass: 78±8 kg, body fat: 8.9±2.5 %) trained three times per week for 6 weeks. During session 1 and 3 of each week, participants performed six sets of two repetitions of eccentric half squats against a load of 65% of one repetition maximum (1RM), separated by 4 min of recovery. Participants were instructed to lower the weight fast and then decelerate rapidly until knee angle reached 90o. The weight was then lifted by two assistants and the next repetition was performed. During session 2 of each week, participants performed six sets of four maximal effort jump squats against a load corresponding to 30% of 1RM, separated by 4 min of recovery. In the first, second and third minute of each recovery interval of all sets in every training session, participants performed a maximal countermovement jump. Before and after 6 weeks of training, vertical jump height was assessed and muscle biopsies were obtained from the vastus lateralis of seven participants. Muscle biopsy data were analyzed using two-way ANOVA with repeated measures and performance data were compared using paired t-test (p<0.05). RESULTS: Vertical jump height increased from 37.3±4.1 to 43.7± 5.4 cm (p=0.002). The percentage of type I, IIA and IIX fibres remained unchanged after training (type I: 46.8±3.0 vs. 46.2±3.4%, type IIA: 40.2±3.4 vs. 41.0±4.4%, type IIX: 13.0±1.5 vs. 12.8±1.6%, pre vs. post training). However, fiber cross-sectional area increased equally (by 9.4±2.0%, p<0.01) in all fiber types after training (type I: from 4705±243 to 5132±225 μm2, type IIA: from 5939±263 to 6421±271 μm2, type IIX: from 5004±253 to 5568±325 μm2, p=0.003). CONCLUSION: These data show that this combination of eccentric and ballistic strength training increases leg muscle power and muscle fibre cross sectional area in all fibre types, without causing a decrease in the percentage of type IIX fibres. The relatively large increase in vertical jump performance (17.0±3.3%) over a relatively short training period (6 weeks or 18 training sessions) suggests that this program may be effective for fast gains in leg muscle power
    ACSM 60th Annual Meeting 2013, Indianapolis, Indiana, USA; 05/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: Time rate of blood pressure (BP) variation is a measure of the speed of BP fluctuations derived from a computerized analysis of ambulatory BP monitoring. The aim of this study was to identify pathophysiological differences in the time rate of BP variation between stroke subtypes, on the basis of the Trial of Org 10172 in Acute Stroke Treatment criteria, in the acute phase and to examine the impact of time rate of BP variation on outcome at 1 year after stroke. PATIENTS AND METHODS: A consecutive series of 109 first-ever stroke patients, who fulfilled our inclusion criteria, underwent 24 h ambulatory BP monitoring within 24 h after the onset of stroke. On the basis of the patients' Modified Rankin Scale score at 1 year after stroke, the study population was divided into two groups: patients with a positive (n=73) and those with a negative outcome (n=36). RESULTS: The 24-h rate of systolic BP variation is higher in patients with large artery atherosclerosis [0.692 mmHg/min; 95% confidence interval (CI) 0.627-0.757] compared with those with lacunar strokes (0.609 mmHg/min; 95% CI 0.579-0.640) or strokes of unknown etiology (0.586 mmHg/min; 95% CI 0.522-0.649). Moreover, patients with higher 24-h rates of systolic BP variation were more likely to have a negative outcome at 1 year (odds ratio 1.96; 95% CI 1.16-3.32). Moreover, each 0.1 mmHg/min increase in the 24-h rate of SBP variation was associated with a 1.96-fold increase in the odds of a negative outcome (95% CI 1.16-3.32). CONCLUSION: Time rate of BP variation shows significant differences between stroke subtypes in the acute phase of the event, and it is associated with outcome at 1 year. Lowering the time rate of BP variation, in the acute phase, might lead to better outcomes in patients who have had a cerebrovascular incident.
    Blood pressure monitoring 02/2013; · 1.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power) training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9) and Power (n = 8) groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ), Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively). Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively), while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05). Muscle fibre Cross Sectional Area (fCSA) increased in all fibre types after Strength training by 19-26% (p < 0.05), while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (%) decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations. Key pointsBallistic-power training with 30% of 1RM is equally effective in increasing shot put performance as strength training, in novice throwers, during a short training cycle of six weeks.In novice shot putters with relatively low initial muscle strength/mass, short-term strength training might be more important since it can increase both muscle strength and shot put performance.The ballistic type of power training resulted in a significant increase of the mass of type IIx muscle fibres and no change in their proportion. Thus, this type of training might be used effectively during the last weeks before competition, when the strength training load is usually reduced, in order to increase muscle power and shot put performance in novice shot putters.
    Journal of sports science & medicine 01/2013; 12(1):130-7. · 0.89 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power) training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9) and Power (n = 8) groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ), Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively). Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively), while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05). Muscle fibre Cross Sectional Area (fCSA) increased in all fibre types after Strength training by 19-26% (p < 0.05), while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (%) decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations.
    Journal of sports science & medicine 01/2013; 12:130-137. · 0.89 Impact Factor
  • 8th International Conference on Strength Training; 10/2012
  • 2nd Congress of Biochemistry and Physiology of Exercise; 10/2012
  • 2nd Congress of Biochemistry and Physiology of Exercise; 10/2012
  • 2nd Congress of Biochemistry and Physiology of Exercise; 10/2012
  • 2nd Congress of Biochemistry and Physiology of Exercise; 10/2012
  • Blood pressure monitoring 10/2012; 17(5):220-1. · 1.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We compared among young patients with ischemic stroke the distribution of vascular risk factors among sex, age groups, and 3 distinct geographic regions in Europe. We included patients with first-ever ischemic stroke aged 15 to 49 years from existing hospital- or population-based prospective or consecutive young stroke registries involving 15 cities in 12 countries. Geographic regions were defined as northern (Finland, Norway), central (Austria, Belgium, France, Germany, Hungary, The Netherlands, Switzerland), and southern (Greece, Italy, Turkey) Europe. Hierarchical regression models were used for comparisons. In the study cohort (n=3944), the 3 most frequent risk factors were current smoking (48.7%), dyslipidemia (45.8%), and hypertension (35.9%). Compared with central (n=1868; median age, 43 years) and northern (n=1330; median age, 44 years) European patients, southern Europeans (n=746; median age, 41 years) were younger. No sex difference emerged between the regions, male:female ratio being 0.7 in those aged <34 years and reaching 1.7 in those aged 45 to 49 years. After accounting for confounders, no risk-factor differences emerged at the region level. Compared with females, males were older and they more frequently had dyslipidemia or coronary heart disease, or were smokers, irrespective of region. In both sexes, prevalence of family history of stroke, dyslipidemia, smoking, hypertension, diabetes mellitus, coronary heart disease, peripheral arterial disease, and atrial fibrillation positively correlated with age across all regions. Primary preventive strategies for ischemic stroke in young adults-having high rate of modifiable risk factors-should be targeted according to sex and age at continental level.
    Stroke 07/2012; 43(10):2624-30. · 6.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Current evidence suggests cardiac involvement and electrocardiographic changes of increasing frequency with age in patients with myotonic dystrophy type 2 (DM2). Myocyte hypertrophy with concurrent fibrosis seems to be the anatomical correlate. Moreover, morphological and functional changes indicative of subclinical cardiomyopathy have been demonstrated by means of cardiac magnetic resonance imaging (CMRI) and spectroscopy in patients with no overt cardiac disease. We present a 68-year-old woman with genetically established DM2 and no clinical, electrocardiographic or echocardiographic signs indicative of cardiac involvement. CMRI revealed delayed contrast enhancement of the anterior portion of the interventricular septum, indicating myocardial involvement. Contrast-enhanced CMRI might be a useful diagnostic tool in assessing cardiac involvement in cases of DM2. The role of delayed contrast enhancement should be further investigated in order to elucidate the cardiac features of this fascinating multisystem disease.
    Hellenic journal of cardiology: HJC = Hellēnikē kardiologikē epitheōrēsē 07/2012; 53(4):324-6. · 1.23 Impact Factor

Publication Stats

1k Citations
474.44 Total Impact Points

Institutions

  • 2003–2014
    • Eginition Hospital Athens
      Athínai, Attica, Greece
  • 2011–2013
    • University of Ioannina
      • Division of Internal Medicine II
      Ioánnina, Ipeiros, Greece
  • 2004–2013
    • Athens State University
      Athens, Alabama, United States
  • 2006–2011
    • National and Kapodistrian University of Athens
      • Division of Neurology II
      Athens, Attiki, Greece
  • 2003–2010
    • Alexandra Regional General Hospital
      Athínai, Attica, Greece
  • 2007
    • University of Alabama at Birmingham
      • Department of Neurology
      Birmingham, AL, United States
  • 1998–2001
    • Universität Heidelberg
      • Neurological Clinic
      Heidelberg, Baden-Wuerttemberg, Germany