Hana Hansíková - Academia.edu (original) (raw)
Papers by Hana Hansíková
Journal of neurology, Mar 23, 2024
This study presents an in-depth analysis of mitochondrial enzyme activities in Friedreich's ataxi... more This study presents an in-depth analysis of mitochondrial enzyme activities in Friedreich's ataxia (FA) patients, focusing on the Electron Transport Chain complexes I, II, and IV, the Krebs Cycle enzyme Citrate Synthase, and Coenzyme Q10 levels. It examines a cohort of 34 FA patients, comparing their mitochondrial enzyme activities and clinical parameters, including disease duration and cardiac markers, with those of 17 healthy controls. The findings reveal marked reductions in complexes II and, specifically, IV, highlighting mitochondrial impairment in FA. Additionally, elevated Neurofilament Light Chain levels and cardiomarkers were observed in FA patients. This research enhances our understanding of FA pathophysiology and suggests potential biomarkers for monitoring disease progression. The study underscores the need for further clinical trials to validate these findings, emphasizing the critical role of mitochondrial dysfunction in FA assessment and treatment. Keywords Friedreich's ataxia • Mitochondrial dysfunction • Complex IV (COX) • Complex I (NQR) • Complex II (SQR) • Ubiquinone (Coenzyme Q10) • Neurofilament light chain (NFL) • Biomarkers • Disease monitoring • Therapeutic monitoring Abbreviations ADL Activities of Daily Living ATP Adenosine Triphosphate AVG ADL Average Activities of Daily Living per year of disease duration AVG SARA Average Scale for the Assessment and Rating of Ataxia per year of disease duration COX Cytochrome c Oxidase (Complex IV) CS Citrate Synthase
Stem Cell Research, Oct 1, 2022
Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2006
Autoři prezentuji připad 13-měsicniho batolete, ktere bylo na nasem pracovisti vysetřovano pro bl... more Autoři prezentuji připad 13-měsicniho batolete, ktere bylo na nasem pracovisti vysetřovano pro bliže neobjasněnou psychomotorickou retardaci na urovni 2.trimenonu, stigmatizaci, mikrocefalii, strabismus, invertovane prsni bradavky, atypickou distribuci podkožniho tuku a hepatopatii. V ramci diferencialni diagnostiky byl proveden metabolický screening k vylouceni dědicne poruchy metabolizmu vcetně zaměřeni na možnou dědicnou poruchu glykosylace. Byla provedena izoelektricka fokuzace transferinu, ktera prokazala patologicke spektrum sialovaných forem transferinu: snižený tetrasialotransferin a zvýsený disialotransferin a asialotransferin typ I. Pozitivni screening na poruchu N glykosylace proteinů byl nasledně potvrzen molekularně-genetickým vysetřenim genu PMM2 (MIM*601785). Pacient je složeným heterozygotem c.[338C>T]; c.[422G>A] pro mutace v genu PMM2. Jedna se o prvni připad z naseho pracovistě. Prace vznikla za podpory projektu MZ CR AZV 16-31932A
PubMed, Oct 1, 1993
Leigh's syndrome--subacute necrotizing encephalomyopathy--is a serious disease of child age manif... more Leigh's syndrome--subacute necrotizing encephalomyopathy--is a serious disease of child age manifested by severe psychomotor retardation, a varied neurological symptomatology, a typically symmetrical neuropathological affection of the central nervous system in the area of the basal ganglia and a metabolic disorder affecting the energy system of cells. The authors describe the clinical course of the disease and the results of metabolic and neuropathological investigations in an infant with Leigh's syndrome and severe lactate acidosis based on deficiency of complex I activity of the respiratory chain.
PubMed, 2007
Chondrodysplasia punctata represents clinically and genetically a heterogeneous group of disorder... more Chondrodysplasia punctata represents clinically and genetically a heterogeneous group of disorders characterized by the presence of multiple congenital anomalies and stippled epiphyses. We present clinical course of the disease and the results of metabolic, X-ray and molecular analyses in 19-months old girl with X-linked dominant chondrodysplasia punctata with intrauterine growth retardation, craniofacial dysmorphy, cataracts, cutaneous anomalies including ichthyosis, asymmetric rhizomesomelic shortness of the limbs, deformity of the spine, club foot, polydactyly, syndactyly, epiphyseal stippling and low cholesterol (2.29 mmol/l). Spectrophotometric analysis revealed the presence of abnormal pattern of cholesterol precursors in blood. The increased level of 8-dehydrocholesterol (42.2 micromol/l, controls < 1) and 7-dehydrocholesterol (25.5 micromol/l, controls < 1) recognised with GC/MS suggested an endogenous defect of cholesterol biosynthesis. The diagnosis of X-linked dominant chondrodysplasia punctata (CDPX2) was confirmed by the molecular analysis. Sequencing of the EBP gene encoding for 3beta-hydroxysteroid-delta8,delta7-isomerase revealed the presence of "de novo" heterozygous mutation c.327C>T (p.Arg110Stop). High cholesterol diet normalized cholesterol level (3.28 mmol/l) but it had no influence on the unfavourable prognosis of the disease. Low level of cholesterol with abnormal sterol profile in a child with congenital development anomalies represent an important laboratory marker suggesting an inherited defect of cholesterol biosynthesis.
PubMed, Jun 28, 1999
Background: The most frequent manifestation of mitochondrial DNA (mtDNA) mutation 8344 A-->G is M... more Background: The most frequent manifestation of mitochondrial DNA (mtDNA) mutation 8344 A-->G is MERRF syndrome (Myoclonic Epilepsy and Myopathy with Ragged Red Fibres). Less frequent symptoms include ataxia, perceptive type of deafness, cardiomyopathy or external ophthalmoplegia and mental and motor retardation in children. We describe heterogeneity of clinical symptoms and results of biochemical and molecular investigations in four families with the heteroplasmic mutation 8344 A-->G in mtDNA. Methods and results: In co-operation with paediatric, neurological and genetic specialists from the Czech and Slovak Republic we found in 1993-1998 at the enzymatic or molecular level more than 90 children and adults with impaired mitochondrial energy metabolism. Heteroplasmic mutation 8344 A-->G in mtDNA was found in four families. Ataxia and progressive muscle weakness appeared in the first proband with 50% of mutated copies of mtDNA in muscle at the age of 30 years. The second proband with 95% of mutated mtDNA had his first clinical symptoms--muscle hypotonia, cardiomyopathy and mental and motor retardation--in infancy while his four relatives with 25-50% mutated mtDNA lack so far clinical symptoms. In a female from the third family with 50% mutated mtDNA in muscle the disease manifested at the age of 42 years with progressive external ophthalmoplegia (PEO) and muscle weakness. In the fourth proband with 50% of mutated mtDNA in blood the disease started in infancy with spastic quadruparesis and arrested mental and motor development. Enzymatic and histochemical investigation in muscle biopsy in two probands revealed lower cytochrom c oxidase activity. Ragged-red fibres were found only in one adult patient. Conclusions: MtDNA mutation 8344 A-->G can manifest by heterogeneous symptoms. A higher percentage of mutated mtDNA is usually associated with more serious forms of the disease, but there is not always a correlation between the degree of heteroplasmy and severity of the disease or the age of the first clinical symptoms.
PubMed, 2005
Carnitine plays an important role in energetic metabolism. The aim of the study was to characteri... more Carnitine plays an important role in energetic metabolism. The aim of the study was to characterize the carnitine status in term and preterm newborns with respect to gestational age, birth weight, haematocrit and red blood cell count (RBC). The effect of nutrition on carnitine levels in the first week of life was also studied. Total blood pool of free carnitine (FC), acylcarnitines (AC) and total carnitine (TC) were analysed in whole cord blood and postnatally in capillary blood obtained at the day 4-6 in 33 term newborns and at the day 7-10 in 27 preterm newborns using tandem mass spectrometry. Plasma level of carnitine in the cord blood was measured using radioenzymatic method. Cord plasma levels of FC, AC and TC were higher in preterm newborns in comparison with term newborns (p < 0.01), but the total blood pool of FC and TC in whole cord blood was lower in preterm newborns than in term newborns (p < 0.01) and positive correlation was found between FC and gestational age or birth weight (p < 0.05). In addition, positive correlation was found between AC and red blood cell count or haematocrit (p < 0.05). During the first week of life, blood pool of FC and TC in term newborns and AC and TC in preterm newborns decreased regardless of the type of enteral or parenteral nutrition. Our results indicate that preterm newborns are born with limited carnitine store. Interpretation of carnitine analyses in whole blood relies in addition to gestational age and birth weight on the haematocrit, especially in newborns with anaemia or blood hyperviscosity.
International Journal of Obesity, Dec 11, 2018
Background/objective Adaptation to the extrauterine environment depends on a switch from glycolys... more Background/objective Adaptation to the extrauterine environment depends on a switch from glycolysis to catabolism of fatty acids (FA) provided as milk lipids. We sought to learn whether the postnatal induction of muscle FA oxidation in mice could reflect propensity to obesity and to characterize the mechanisms controlling this induction. Methods Experiments were conducted using obesity-resistant A/J and obesity-prone C57BL/6J (B6) mice maintained at 30°C, from 5 to 28 days after birth. At day 10, both A/J and B6 mice with genetic ablation (KO) of α2 subunit of AMPactivated protein kinase (AMPK) were also used. In skeletal muscle, expression of selected genes was determined using quantitative real-time PCR, and AMPK subunits content was evaluated using Western blotting. Activities of both AMPK and pyruvate dehydrogenase (PDH), as well as acylcarnitine levels in the muscle were measured. Results Acylcarnitine levels and gene expression indicated transient increase in FA oxidation during the first 2 weeks after birth, with a stronger increase in A/J mice. These data correlated with (i) the surge in plasma leptin levels, which peaked at day 10 and was higher in A/J mice, and (ii) relatively low activity of PDH linked with up-regulation of PDH kinase 4 gene (Pdk4) expression in the 10-day-old A/J mice. In contrast with the Pdk4 expression, transient up-regulation of uncoupling protein 3 gene was observed in B6 but not A/J mice. AMPK activity changed during the development, without major differences between A/J and B6 mice. Expression of neither Pdk4 nor other muscle genes was affected by AMPK-KO. Conclusions Our results indicate a relatively strong postnatal induction of FA oxidation in skeletal muscle of the obesityresistant A/J mice. This induction is transient and probably results from suppression of PDH activity, linked with a postnatal surge in plasma leptin levels, independent of AMPK.
PubMed, Oct 11, 2002
Background: Leigh disease, subacute necrotizing encephalopathy, is a serious mitochondrial disord... more Background: Leigh disease, subacute necrotizing encephalopathy, is a serious mitochondrial disorder of energy-providing metabolism. Clinical presentation usually starts in infancy as a progressive neurodegenerative disorder with retardation and regression of psychomotor development. The most common form of the disease is associated with deficiency of the cytochrome c oxidase (COX) due to SURF1 gene mutations. SURF1 encodes an inner mitochondrial membrane protein involved in the biogenesis and assembly of COX complex. Methods and results: The activities of mitochondrial respiratory chain complexes were determined spectrophotometrically in isolated lymphocytes, platelets, muscle mitochondria and cultured fibroblasts. Generalised decrease of COX activity was found in 7 children with typical symptoms of Leigh disease. Two-dimensional electrophoresis of mitochondrial proteins showed altered assembly pattern of COX. As demonstrated by Western blot analysis of mitochondria or mitoplasts with anti-hSurf1 antibodies (gift from Dr. E. A. Shoubridge), the Surf1 protein was absent in all 5 investigated patients. Molecular analyses in the 7 patients revealed the presence of mutations in the SURF1 gene--six patients harboured previously described SURF1 mutations, a new mutation 574C > T was found in one patient. Conclusions: The co-operation among the patient's families, clinicians and specialised laboratories is essential for the diagnostic of mitochondrial disorders. The treatment of Leigh syndrome is only symptomatic and the prognosis of the disease is unfavourable. The diagnostics on biochemical and molecular level is necessary for genetic counselling and prenatal diagnosis in affected families.
Molecular Genetics and Metabolism, Aug 1, 2016
PubMed, Jul 13, 1998
Background: A heteroplasmic A3243G point mutation in tRNALeu(UUR) gene of mitochondrial DNA (mtDN... more Background: A heteroplasmic A3243G point mutation in tRNALeu(UUR) gene of mitochondrial DNA (mtDNA) is found in patients with MELAS syndrome (Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes), less frequently in patients with other dominating clinical features, such as deafness, diabetes mellitus type 2, hypertrophic cardiomyopathy, renal problems or inborn development defects. Present report describes histochemical, enzymatic and molecular biology studies of the family with clinical variant of meals syndrome. Methods and results: A 45-year-old woman with progressive muscle weakness, external ophtalmoplegia, perceptive deafness, ischemic heart disease, diabetes mellitus type 2 and hyperlactacidemia was metabolically investigated because the multiorgan problems indicated mitochondrial origin of the disease. Muscle biopsy revealed pronounced myopathic changes, ragged red fibers and decreased activity of respiratory chain enzymes - succinate cytochrome c reductase (< 5% control) and cytochrome c oxidase (< 10% control). Restriction fragment analysis of mtDNA from muscle, blood and hair follicles detected heteroplasmic A -> G mutation in the position 3243 of the tRNALeu(UUR) gene, which was more pronounced in muscle (28% of total mtDNA) than in blood (12%) or in hair follicles (10%). No mutation was found in blood and hair follicles of patient's mother and daughter. Conclusions: Diagnostics of mitochondrial diseases require close collaboration of clinicians with specialised laboratories. Treatment of mitochondrial disorders is only symptomatic, however, early diagnosis of the molecular defect is important for genetic counselling.
Prague medical report, 2011
The most common cause of pyruvate dehydrogenase complex (PDHc) deficiency is the deficit of the E... more The most common cause of pyruvate dehydrogenase complex (PDHc) deficiency is the deficit of the E1α-subunit. The aim of this study was to describe distinct course of the disease in two boys with mutations in PDHA1 gene and illustrate the possible obstacles in measurement of PDHc activity. Clinical data and metabolic profiles were collected and evaluated. PDHc and E1α-subunit activities were measured using radiometric assay. Subunits of PDHc were detected by Western blot. PDHA1 gene was analysed by direct sequencing. In patient 1, the initial hypotonia with psychomotor retardation was observed since early infancy. The child gradually showed symptoms of spasticity and arrest of psychomotor development. In patient 2, the disease manifested by seizures and hyporeflexia in the toddler age. The diagnosis was confirmed at the age of seven years after attacks of dystonia and clinical manifestation of myopathy with normal mental development.
Physiological Research, Feb 18, 2018
Acta Ophthalmologica, Feb 7, 2013
To identify the underlying molecular genetic cause in a Czech family with optic atrophy, deafness... more To identify the underlying molecular genetic cause in a Czech family with optic atrophy, deafness, ptosis, ophthalmoplegia, polyneuropathy and ataxia transmitted as an autosomal dominant trait. Ophthalmological and neurological examination followed by molecular genetic analyses. Seven family members were clinically affected. There was a variable but progressive visual, hearing and neurological disability across the family as a whole. The majority of subjects presented with impairment of visual function and a variable degree of ptosis and/or ophthalmoplegia from the first to the third decade of life. Deafness, neuropathy and ataxia appeared later, in the third and fourth decade. Migraine, tachycardia, intention tremor, nystagmus and cervical dystonia were observed in isolated individuals. A significant overall feature was the high level of neurological disability leading to 3 of 4 members being unable to walk or stand unaided before the age of 60 years. A novel missense mutation c.1345A&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;C (p.Thr449Pro) in OPA1 segregating with the disease phenotype over three generations was detected. In silico analysis supported pathogenicity of the identified sequence variant. Our work expands the spectrum of mutation in OPA1, which may lead to severe multisystem neurological disorder. The molecular genetic cause of dominant optic atrophy in the Czech population is reported for the first time. We propose that regular cardiac follow-up in patients diagnosed with dominant optic atrophy and widespread neurological disease should be considered.
PubMed, 2006
Background: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a disorder with auto... more Background: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a disorder with autosomal recessive inheritance caused by mutations in the gene encoding thymidine phosphorylase (TP). TP deficiency results in imbalance of mitochondrial pool of nucleotides leading secondary to multiple deletions and depletion of mitochondrial DNA (mtDNA) and impairment of oxidative phosphorylation system. The disease is clinically characterized by gastrointestinal dysmotility with symptoms of pseudo-obstruction, severe failure to thrive, ptosis, leukoencephalopathy, peripheral neuropathy and myopathy. We present results of the clinical, histochemical, biochemical and molecular analyses of the first Czech patient with MNGIE syndrome. Methods and results: Man, 33-years old with twenty-year history of failure to thrive (height 168 cm, weight 34 kg) and progressive gastrointestinal dysmotility, external ophthalmoplegia, leucoencephalopathy and peripheral neuropathy was recommended to metabolic center. Histochemical analyses in muscle biopsy showed the presence of "ragged red fibers" with focal decrease of cytochrome c oxidase activity, but spectrophotometric analyses in isolated muscle mitochondria revealed normal activities of all respiratory chain complexes. Metabolic investigation revealed markedly increased plasma level of thymidine (6.6 micromol/l, controls <0.05 micromol/l) and deoxyuridine (15 micromol/l, controls <0.05 micromol/l). The activity of TP in isolated lymphocytes was low (0.02 micromol/hour/mg protein, reference range 0.78 +/- 0.18). Molecular analyses in muscle biopsy revealed multiple mtDNA deletions and homozygous mutation 1419G>A (Gly145Arg) was found in gene for TP. Both parents are heterozygotes. Conclusions: MNGIE has to be considered in patients presenting with a combination of gastrointestinal and neurological symptoms. Plasma level of thymidine may serve as the best method for laboratory screening of MNGIE, but molecular analyses are necessary for genetic counselling and prenatal diagnosis in affected families.
Antioxidants, Dec 11, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of neurology, Mar 23, 2024
This study presents an in-depth analysis of mitochondrial enzyme activities in Friedreich's ataxi... more This study presents an in-depth analysis of mitochondrial enzyme activities in Friedreich's ataxia (FA) patients, focusing on the Electron Transport Chain complexes I, II, and IV, the Krebs Cycle enzyme Citrate Synthase, and Coenzyme Q10 levels. It examines a cohort of 34 FA patients, comparing their mitochondrial enzyme activities and clinical parameters, including disease duration and cardiac markers, with those of 17 healthy controls. The findings reveal marked reductions in complexes II and, specifically, IV, highlighting mitochondrial impairment in FA. Additionally, elevated Neurofilament Light Chain levels and cardiomarkers were observed in FA patients. This research enhances our understanding of FA pathophysiology and suggests potential biomarkers for monitoring disease progression. The study underscores the need for further clinical trials to validate these findings, emphasizing the critical role of mitochondrial dysfunction in FA assessment and treatment. Keywords Friedreich's ataxia • Mitochondrial dysfunction • Complex IV (COX) • Complex I (NQR) • Complex II (SQR) • Ubiquinone (Coenzyme Q10) • Neurofilament light chain (NFL) • Biomarkers • Disease monitoring • Therapeutic monitoring Abbreviations ADL Activities of Daily Living ATP Adenosine Triphosphate AVG ADL Average Activities of Daily Living per year of disease duration AVG SARA Average Scale for the Assessment and Rating of Ataxia per year of disease duration COX Cytochrome c Oxidase (Complex IV) CS Citrate Synthase
Stem Cell Research, Oct 1, 2022
Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2006
Autoři prezentuji připad 13-měsicniho batolete, ktere bylo na nasem pracovisti vysetřovano pro bl... more Autoři prezentuji připad 13-měsicniho batolete, ktere bylo na nasem pracovisti vysetřovano pro bliže neobjasněnou psychomotorickou retardaci na urovni 2.trimenonu, stigmatizaci, mikrocefalii, strabismus, invertovane prsni bradavky, atypickou distribuci podkožniho tuku a hepatopatii. V ramci diferencialni diagnostiky byl proveden metabolický screening k vylouceni dědicne poruchy metabolizmu vcetně zaměřeni na možnou dědicnou poruchu glykosylace. Byla provedena izoelektricka fokuzace transferinu, ktera prokazala patologicke spektrum sialovaných forem transferinu: snižený tetrasialotransferin a zvýsený disialotransferin a asialotransferin typ I. Pozitivni screening na poruchu N glykosylace proteinů byl nasledně potvrzen molekularně-genetickým vysetřenim genu PMM2 (MIM*601785). Pacient je složeným heterozygotem c.[338C>T]; c.[422G>A] pro mutace v genu PMM2. Jedna se o prvni připad z naseho pracovistě. Prace vznikla za podpory projektu MZ CR AZV 16-31932A
PubMed, Oct 1, 1993
Leigh's syndrome--subacute necrotizing encephalomyopathy--is a serious disease of child age manif... more Leigh's syndrome--subacute necrotizing encephalomyopathy--is a serious disease of child age manifested by severe psychomotor retardation, a varied neurological symptomatology, a typically symmetrical neuropathological affection of the central nervous system in the area of the basal ganglia and a metabolic disorder affecting the energy system of cells. The authors describe the clinical course of the disease and the results of metabolic and neuropathological investigations in an infant with Leigh's syndrome and severe lactate acidosis based on deficiency of complex I activity of the respiratory chain.
PubMed, 2007
Chondrodysplasia punctata represents clinically and genetically a heterogeneous group of disorder... more Chondrodysplasia punctata represents clinically and genetically a heterogeneous group of disorders characterized by the presence of multiple congenital anomalies and stippled epiphyses. We present clinical course of the disease and the results of metabolic, X-ray and molecular analyses in 19-months old girl with X-linked dominant chondrodysplasia punctata with intrauterine growth retardation, craniofacial dysmorphy, cataracts, cutaneous anomalies including ichthyosis, asymmetric rhizomesomelic shortness of the limbs, deformity of the spine, club foot, polydactyly, syndactyly, epiphyseal stippling and low cholesterol (2.29 mmol/l). Spectrophotometric analysis revealed the presence of abnormal pattern of cholesterol precursors in blood. The increased level of 8-dehydrocholesterol (42.2 micromol/l, controls < 1) and 7-dehydrocholesterol (25.5 micromol/l, controls < 1) recognised with GC/MS suggested an endogenous defect of cholesterol biosynthesis. The diagnosis of X-linked dominant chondrodysplasia punctata (CDPX2) was confirmed by the molecular analysis. Sequencing of the EBP gene encoding for 3beta-hydroxysteroid-delta8,delta7-isomerase revealed the presence of "de novo" heterozygous mutation c.327C>T (p.Arg110Stop). High cholesterol diet normalized cholesterol level (3.28 mmol/l) but it had no influence on the unfavourable prognosis of the disease. Low level of cholesterol with abnormal sterol profile in a child with congenital development anomalies represent an important laboratory marker suggesting an inherited defect of cholesterol biosynthesis.
PubMed, Jun 28, 1999
Background: The most frequent manifestation of mitochondrial DNA (mtDNA) mutation 8344 A-->G is M... more Background: The most frequent manifestation of mitochondrial DNA (mtDNA) mutation 8344 A-->G is MERRF syndrome (Myoclonic Epilepsy and Myopathy with Ragged Red Fibres). Less frequent symptoms include ataxia, perceptive type of deafness, cardiomyopathy or external ophthalmoplegia and mental and motor retardation in children. We describe heterogeneity of clinical symptoms and results of biochemical and molecular investigations in four families with the heteroplasmic mutation 8344 A-->G in mtDNA. Methods and results: In co-operation with paediatric, neurological and genetic specialists from the Czech and Slovak Republic we found in 1993-1998 at the enzymatic or molecular level more than 90 children and adults with impaired mitochondrial energy metabolism. Heteroplasmic mutation 8344 A-->G in mtDNA was found in four families. Ataxia and progressive muscle weakness appeared in the first proband with 50% of mutated copies of mtDNA in muscle at the age of 30 years. The second proband with 95% of mutated mtDNA had his first clinical symptoms--muscle hypotonia, cardiomyopathy and mental and motor retardation--in infancy while his four relatives with 25-50% mutated mtDNA lack so far clinical symptoms. In a female from the third family with 50% mutated mtDNA in muscle the disease manifested at the age of 42 years with progressive external ophthalmoplegia (PEO) and muscle weakness. In the fourth proband with 50% of mutated mtDNA in blood the disease started in infancy with spastic quadruparesis and arrested mental and motor development. Enzymatic and histochemical investigation in muscle biopsy in two probands revealed lower cytochrom c oxidase activity. Ragged-red fibres were found only in one adult patient. Conclusions: MtDNA mutation 8344 A-->G can manifest by heterogeneous symptoms. A higher percentage of mutated mtDNA is usually associated with more serious forms of the disease, but there is not always a correlation between the degree of heteroplasmy and severity of the disease or the age of the first clinical symptoms.
PubMed, 2005
Carnitine plays an important role in energetic metabolism. The aim of the study was to characteri... more Carnitine plays an important role in energetic metabolism. The aim of the study was to characterize the carnitine status in term and preterm newborns with respect to gestational age, birth weight, haematocrit and red blood cell count (RBC). The effect of nutrition on carnitine levels in the first week of life was also studied. Total blood pool of free carnitine (FC), acylcarnitines (AC) and total carnitine (TC) were analysed in whole cord blood and postnatally in capillary blood obtained at the day 4-6 in 33 term newborns and at the day 7-10 in 27 preterm newborns using tandem mass spectrometry. Plasma level of carnitine in the cord blood was measured using radioenzymatic method. Cord plasma levels of FC, AC and TC were higher in preterm newborns in comparison with term newborns (p < 0.01), but the total blood pool of FC and TC in whole cord blood was lower in preterm newborns than in term newborns (p < 0.01) and positive correlation was found between FC and gestational age or birth weight (p < 0.05). In addition, positive correlation was found between AC and red blood cell count or haematocrit (p < 0.05). During the first week of life, blood pool of FC and TC in term newborns and AC and TC in preterm newborns decreased regardless of the type of enteral or parenteral nutrition. Our results indicate that preterm newborns are born with limited carnitine store. Interpretation of carnitine analyses in whole blood relies in addition to gestational age and birth weight on the haematocrit, especially in newborns with anaemia or blood hyperviscosity.
International Journal of Obesity, Dec 11, 2018
Background/objective Adaptation to the extrauterine environment depends on a switch from glycolys... more Background/objective Adaptation to the extrauterine environment depends on a switch from glycolysis to catabolism of fatty acids (FA) provided as milk lipids. We sought to learn whether the postnatal induction of muscle FA oxidation in mice could reflect propensity to obesity and to characterize the mechanisms controlling this induction. Methods Experiments were conducted using obesity-resistant A/J and obesity-prone C57BL/6J (B6) mice maintained at 30°C, from 5 to 28 days after birth. At day 10, both A/J and B6 mice with genetic ablation (KO) of α2 subunit of AMPactivated protein kinase (AMPK) were also used. In skeletal muscle, expression of selected genes was determined using quantitative real-time PCR, and AMPK subunits content was evaluated using Western blotting. Activities of both AMPK and pyruvate dehydrogenase (PDH), as well as acylcarnitine levels in the muscle were measured. Results Acylcarnitine levels and gene expression indicated transient increase in FA oxidation during the first 2 weeks after birth, with a stronger increase in A/J mice. These data correlated with (i) the surge in plasma leptin levels, which peaked at day 10 and was higher in A/J mice, and (ii) relatively low activity of PDH linked with up-regulation of PDH kinase 4 gene (Pdk4) expression in the 10-day-old A/J mice. In contrast with the Pdk4 expression, transient up-regulation of uncoupling protein 3 gene was observed in B6 but not A/J mice. AMPK activity changed during the development, without major differences between A/J and B6 mice. Expression of neither Pdk4 nor other muscle genes was affected by AMPK-KO. Conclusions Our results indicate a relatively strong postnatal induction of FA oxidation in skeletal muscle of the obesityresistant A/J mice. This induction is transient and probably results from suppression of PDH activity, linked with a postnatal surge in plasma leptin levels, independent of AMPK.
PubMed, Oct 11, 2002
Background: Leigh disease, subacute necrotizing encephalopathy, is a serious mitochondrial disord... more Background: Leigh disease, subacute necrotizing encephalopathy, is a serious mitochondrial disorder of energy-providing metabolism. Clinical presentation usually starts in infancy as a progressive neurodegenerative disorder with retardation and regression of psychomotor development. The most common form of the disease is associated with deficiency of the cytochrome c oxidase (COX) due to SURF1 gene mutations. SURF1 encodes an inner mitochondrial membrane protein involved in the biogenesis and assembly of COX complex. Methods and results: The activities of mitochondrial respiratory chain complexes were determined spectrophotometrically in isolated lymphocytes, platelets, muscle mitochondria and cultured fibroblasts. Generalised decrease of COX activity was found in 7 children with typical symptoms of Leigh disease. Two-dimensional electrophoresis of mitochondrial proteins showed altered assembly pattern of COX. As demonstrated by Western blot analysis of mitochondria or mitoplasts with anti-hSurf1 antibodies (gift from Dr. E. A. Shoubridge), the Surf1 protein was absent in all 5 investigated patients. Molecular analyses in the 7 patients revealed the presence of mutations in the SURF1 gene--six patients harboured previously described SURF1 mutations, a new mutation 574C > T was found in one patient. Conclusions: The co-operation among the patient's families, clinicians and specialised laboratories is essential for the diagnostic of mitochondrial disorders. The treatment of Leigh syndrome is only symptomatic and the prognosis of the disease is unfavourable. The diagnostics on biochemical and molecular level is necessary for genetic counselling and prenatal diagnosis in affected families.
Molecular Genetics and Metabolism, Aug 1, 2016
PubMed, Jul 13, 1998
Background: A heteroplasmic A3243G point mutation in tRNALeu(UUR) gene of mitochondrial DNA (mtDN... more Background: A heteroplasmic A3243G point mutation in tRNALeu(UUR) gene of mitochondrial DNA (mtDNA) is found in patients with MELAS syndrome (Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes), less frequently in patients with other dominating clinical features, such as deafness, diabetes mellitus type 2, hypertrophic cardiomyopathy, renal problems or inborn development defects. Present report describes histochemical, enzymatic and molecular biology studies of the family with clinical variant of meals syndrome. Methods and results: A 45-year-old woman with progressive muscle weakness, external ophtalmoplegia, perceptive deafness, ischemic heart disease, diabetes mellitus type 2 and hyperlactacidemia was metabolically investigated because the multiorgan problems indicated mitochondrial origin of the disease. Muscle biopsy revealed pronounced myopathic changes, ragged red fibers and decreased activity of respiratory chain enzymes - succinate cytochrome c reductase (< 5% control) and cytochrome c oxidase (< 10% control). Restriction fragment analysis of mtDNA from muscle, blood and hair follicles detected heteroplasmic A -> G mutation in the position 3243 of the tRNALeu(UUR) gene, which was more pronounced in muscle (28% of total mtDNA) than in blood (12%) or in hair follicles (10%). No mutation was found in blood and hair follicles of patient's mother and daughter. Conclusions: Diagnostics of mitochondrial diseases require close collaboration of clinicians with specialised laboratories. Treatment of mitochondrial disorders is only symptomatic, however, early diagnosis of the molecular defect is important for genetic counselling.
Prague medical report, 2011
The most common cause of pyruvate dehydrogenase complex (PDHc) deficiency is the deficit of the E... more The most common cause of pyruvate dehydrogenase complex (PDHc) deficiency is the deficit of the E1α-subunit. The aim of this study was to describe distinct course of the disease in two boys with mutations in PDHA1 gene and illustrate the possible obstacles in measurement of PDHc activity. Clinical data and metabolic profiles were collected and evaluated. PDHc and E1α-subunit activities were measured using radiometric assay. Subunits of PDHc were detected by Western blot. PDHA1 gene was analysed by direct sequencing. In patient 1, the initial hypotonia with psychomotor retardation was observed since early infancy. The child gradually showed symptoms of spasticity and arrest of psychomotor development. In patient 2, the disease manifested by seizures and hyporeflexia in the toddler age. The diagnosis was confirmed at the age of seven years after attacks of dystonia and clinical manifestation of myopathy with normal mental development.
Physiological Research, Feb 18, 2018
Acta Ophthalmologica, Feb 7, 2013
To identify the underlying molecular genetic cause in a Czech family with optic atrophy, deafness... more To identify the underlying molecular genetic cause in a Czech family with optic atrophy, deafness, ptosis, ophthalmoplegia, polyneuropathy and ataxia transmitted as an autosomal dominant trait. Ophthalmological and neurological examination followed by molecular genetic analyses. Seven family members were clinically affected. There was a variable but progressive visual, hearing and neurological disability across the family as a whole. The majority of subjects presented with impairment of visual function and a variable degree of ptosis and/or ophthalmoplegia from the first to the third decade of life. Deafness, neuropathy and ataxia appeared later, in the third and fourth decade. Migraine, tachycardia, intention tremor, nystagmus and cervical dystonia were observed in isolated individuals. A significant overall feature was the high level of neurological disability leading to 3 of 4 members being unable to walk or stand unaided before the age of 60 years. A novel missense mutation c.1345A&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;C (p.Thr449Pro) in OPA1 segregating with the disease phenotype over three generations was detected. In silico analysis supported pathogenicity of the identified sequence variant. Our work expands the spectrum of mutation in OPA1, which may lead to severe multisystem neurological disorder. The molecular genetic cause of dominant optic atrophy in the Czech population is reported for the first time. We propose that regular cardiac follow-up in patients diagnosed with dominant optic atrophy and widespread neurological disease should be considered.
PubMed, 2006
Background: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a disorder with auto... more Background: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a disorder with autosomal recessive inheritance caused by mutations in the gene encoding thymidine phosphorylase (TP). TP deficiency results in imbalance of mitochondrial pool of nucleotides leading secondary to multiple deletions and depletion of mitochondrial DNA (mtDNA) and impairment of oxidative phosphorylation system. The disease is clinically characterized by gastrointestinal dysmotility with symptoms of pseudo-obstruction, severe failure to thrive, ptosis, leukoencephalopathy, peripheral neuropathy and myopathy. We present results of the clinical, histochemical, biochemical and molecular analyses of the first Czech patient with MNGIE syndrome. Methods and results: Man, 33-years old with twenty-year history of failure to thrive (height 168 cm, weight 34 kg) and progressive gastrointestinal dysmotility, external ophthalmoplegia, leucoencephalopathy and peripheral neuropathy was recommended to metabolic center. Histochemical analyses in muscle biopsy showed the presence of "ragged red fibers" with focal decrease of cytochrome c oxidase activity, but spectrophotometric analyses in isolated muscle mitochondria revealed normal activities of all respiratory chain complexes. Metabolic investigation revealed markedly increased plasma level of thymidine (6.6 micromol/l, controls <0.05 micromol/l) and deoxyuridine (15 micromol/l, controls <0.05 micromol/l). The activity of TP in isolated lymphocytes was low (0.02 micromol/hour/mg protein, reference range 0.78 +/- 0.18). Molecular analyses in muscle biopsy revealed multiple mtDNA deletions and homozygous mutation 1419G>A (Gly145Arg) was found in gene for TP. Both parents are heterozygotes. Conclusions: MNGIE has to be considered in patients presenting with a combination of gastrointestinal and neurological symptoms. Plasma level of thymidine may serve as the best method for laboratory screening of MNGIE, but molecular analyses are necessary for genetic counselling and prenatal diagnosis in affected families.
Antioxidants, Dec 11, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY