The effect of creatine supplementation on myocardial metabolism and function in sedentary and exercised rats

Thesis (PhD (Biomedical Sciences. Medical Physiology))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Background: There has been a dramatic increase in the use of dietary creatine supplementation among sports men and women, and by clinicians as a therapeutic agent in muscular and neurological diseases. The effects of creatine have been studied extensively in skeletal muscle, but knowledge of its myocardial effects is limited. Objectives: To investigate the effects of dietary creatine supplementation with and without exercise on 1) basal cardiac function, 2) susceptibility to ischaemia/reperfusion injury and 3) myocardial protein expression and phosphorylation and 4) mitochondrial oxidative function. Methods: Male Wistar rats were randomly divided into control or creatine supplemented groups. Half of each group was exercise trained by swimming for a period of 8 weeks, 5 days per week. At the end of the 8 weeks the open field test was performed and blood corticosterone levels were measured by RIA to determine whether the swim training protocol had any effects on stress levels of the rats. Afterwards hearts were excised and either freeze-clamped for biochemical and molecular analysis or perfused on the isolated heart perfusion system to assess function and tolerance to ischaemia and reperfusion. Five series of experiments were performed: (i) Mechanical function was documented before and after 20 minutes global ischaemia using the work heart model, (ii) A H2O filled balloon connected to a pressure transducer was inserted into the left ventricle to measure LVDP and ischaemic contracture in the Langendorff model, (iii) The left coronary artery was ligated for 35 minutes and infarct size determined after 30 minutes of reperfusion by conventional TTC staining methods. (iv) Mitochondrial oxidative capacity was quantified. (v) High pressure liquid chromatography (HPLC) and Western Blot analysis were performed on blood and heart tissue for determination of high energy phosphates and protein expression and phosphorylation. Results: Neither the behavioural studies nor the corticosterone levels showed any evidence of stress in the groups investigated. Hearts from creatine supplemented sedentary (33.5 ± 4.5%), creatine supplemented exercised rats (18.22 ± 6.2%) as well as control exercised rats (26.1 ± 5.9%) had poorer aortic output recoveries than the sedentary control group (55.9 ± 4.35% p < 0.01) and there was also greater ischaemic contracture in the creatine supplemented exercised group compared to the sedentary control group (10.4 ± 4.23 mmHg vs 31.63 ± 4.74 mmHg). There were no differences in either infarct size or in mitochondrial oxygen consumption between the groups. HPLC analysis revealed elevated phosphocreatine content (44.51 ±14.65 vs 8.19 ±4.93 nmol/gram wet weight, p < 0.05) as well as elevated ATP levels (781.1 ±58.82 vs 482.1 ±75.86 nmol/gram wet weight, p<0.05) in blood from creatine supplemented vs control sedentary rats. These high energy phosphate elevations were not evident in heart tissue and creatine tranporter expression was not altered by creatine supplementation. GLUT4 and phosphorylated AMPK and PKB/Akt were all significantly higher in the creatine supplemented exercised hearts compared to the control sedentary hearts. Conclusion: This study suggests that creatine supplementation has no effects on basal cardiac function but reduces myocardial tolerance to ischaemia in hearts from exercise trained animals by increasing the ischaemic contracture and decreasing reperfusion aortic output. Exercise training alone also significantly decreased aortic output recovery. However, the exact mechanisms for these adverse myocardial effects are unknown and need further investigation.AFRIKAANSE OPSOMMING: Agtergrond: Die gebruik van kreatien as dieetaanvulling het in die afgelope aantal jaar dramaties toegeneem onder sportlui, sowel as mediese praktisyns wat dit as ‘n terapeutiese middel vir die behandeling van spier- en neurologiese siektes aanwend. Die effekte van kreatien op skeletspier is reeds deeglik ondersoek, maar inligting aangaande die miokardiale effekte van die preperaat is beperk. Doelwitte: Om die effekte van kreatien dieetaanvulling met of sonder oefening ten opsigte van die volgende aspekte te ondersoek: 1) basislyn miokardiale funksie, 2) vatbaarheid vir iskemie/herperfusie besering, 3) proteïenuitdrukking en -fosforilering in die miokardium en 4) mitochondriale oksidatiewe funksie. Metodes: Manlike Wistar rotte is ewekansig in kontrole of kreatien aanvullings groepe verdeel. Helfte van elke groep is aan oefening in die vorm van swemsessies, vir ‘n periode van 8 weke, 5 dae per week blootgestel. Gedrags- en biochemiese toetse is aangewend om die moontlike effek van die swemprotokol op die rotte se stres vlakke te bepaal. In hierdie verband is die oop area toets gebruik, asook bloed kortikosteroon vlakke gemeet deur radioaktiewe immuunessais. Harte is daarna uit die rotte gedissekteer en gevriesklamp vir biochemiese en molekulêre analise, of geperfuseer op die geïsoleerde werkhart perfusiesisteem om sodoende funksie en weerstand teen iskemie en herperfusie beskadeging te bepaal. Vyf eksperimentele reekse is uitgevoer: (i) Meganiese funksie is noteer voor en na 20 minute globale isgemie in die werkhart model; (ii) ‘n Water gevulde plastiek ballon, gekoppel aan ‘n druk omsetter, is in die linker ventrikel geplaas om sodoende linker ventrikulêre ontwikkelde druk (LVDP), asook iskemiese kontraktuur te meet; (iii) Linker koronêre arterie afbinding is vir ‘n periode van 35 minute toegepas en die infarktgrootte bepaal na 30 minute herperfusie deur gebruik te maak van standaard kleuringsmetodes; (iv) Mitochondriale oksidatiewe kapasiteit is gemeet; (v) Hoë druk vloeistof chromatografie (HPLC) en Western Blot analises is uitgevoer op bloed en hartweefsel vir die bepaling van hoë energie fosfate (HEFe), sowel as proteïenuitdrukking en -fosforilering. Resultate: Beide gedragsstudies en kortikosteroonvlakke het geen teken van stres in die betrokke groepe getoon nie. Die groep blootgestel aan kreatienaanvulling en oefening se harte het na iskemie funksioneel swakker herstel as harte van die onaktiewe kontrole groep (18.22±6.2% vs 55.9±4.35%; p<0.01), asook ‘n groter ikgemiese kontraktuur in vergelyking met die onaktiewe kontrole groep ontwikkel (31.63±4.74 mmHg vs 10.4±4.23 mmHg). Daar was geen verskille in infarktgrootte of mitochondriale suurstofverbruik tussen die verskillende groepe waargeneem nie. HPLC analise het verhoogde fosfokreatien (44.51±14.65 vs 8.19±4.93 nmol/gram nat gewig, p<0.05) en adenosientrifosfaat (ATP) bloedvlakke (781.1±58.82 vs 482.1±75.86 nmol/gram nat gewig, p<0.05) in kreatien aanvullings vergelyk met die kontrole groepe getoon. Daar was egter geen meetbare veranderings in HEF vlakke in hartweefsel nie. Gepaardgaande hiermee het kreatienaanvulling geen effek gehad op die uitdrukking va die kreatien transporter nie. In vergelyking met onaktiewe kontrole harte was GLUT4, en fosforileerde AMPK en PKB/ Akt beduidend hoër in harte van geoefende rotte met kreatienaangevulling. Gevolgtrekking: Hierdie data dui daarop dat kreatienaanvulling geen effek op basislyn miokardiale funksie het nie. Kreatienaanvulling het egter die miokardium se weerstand teen iskemiese skade verlaag in harte van rotte blootgestel aan oefening: iskemiese kontraktuur is verhoog en aorta-uitset tydens herperfusie is verlaag. Die presiese meganismes hierby betrokke is egter onbekend en vereis dus verdere studie.Division of Medical Physiology (University of Stellenbosch), The National Research Foundation and the Harry Crossley Fund for financial support

Reduced Purkinje cell number in essential tremor : a postmortem study

Background: Clinical and functional imaging evidence suggests that cerebellar dysfunction occurs in essential tremor (ET). In recent postmortem studies, we documented increased numbers of torpedoes (Purkinje cell axonal swellings) in ET patients without Lewy bodies. Purkinje cell loss, however, has never been rigorously assessed. Objective: To quantitatively assess the number of Purkinje cells in brains of ET patients and similarly aged controls. Methods: Postmortem cerebellar tissue was available in 14 ET cases (6 with Lewy bodies and 8 without Lewy bodies) and 11 controls. Calbindin immunohistochemistry was performed on paraffin sections of the cerebellum. Images were digitally recorded and blinded measurements of the number of Purkinje cells per millimeter of cell layer (linear density) were made. Results: Purkinje cell linear density was inversely correlated with age (r=-0.53, P=.006) and number of torpedoes (r=-0.42, P=.04). Purkinje cell linear density differed by diagnosis (mean [SD], controls, 3.46 [1.27] cells/mm; ET cases with Lewy bodies, 3.33 [1.06] cells/mm; and ET cases without Lewy bodies, 2.14 [0.82] cells/mm; P=.04), with the most significant difference between ET cases without Lewy bodies and controls, where the reduction was 38.2% (P=.04). In an adjusted linear regression analysis that compared ET cases without Lewy bodies with controls, decreased linear density (outcome variable) was associated with ET (β=.56, P=.03). Conclusions: We demonstrated a reduction in Purkinje cell number in the brains of patients with ET who do not have Lewy bodies. These data further support the view that the cerebellum is anatomically, as well as functionally, abnormal in these ET cases

Fall history and associated factors among adults living with HIV-1 in the Cape Winelands, South Africa : an exploratory investigation

CITATION: Berner, K., et al. 2019. Fall history and associated factors among adults living with HIV-1 in the Cape Winelands, South Africa : an exploratory investigation. Open Forum Infectious Diseases, 6(10):ofz401, doi:10.1093/ofid/ofz401.The original publication is available at https://academic.oup.com/ofidPublication of this article was funded by the Stellenbosch University Open Access Fund.Background. People with HIV-1 (PWH) exhibit a high fall incidence and increased fracture risk. As little is known about fall frequency and associated factors in PWH residing in lower-middle-income countries (LMIC), we investigated fall frequency, bone quality, and factors associated with fall history in a South African cohort. Methods. Fifty PWH without obvious predisposing factors for mobility impairments attending 2 public primary care clinics in the Western Cape region participated. Demographic, clinical, and physical performance data were collected. Falls were assessed retrospectively over 12 months. Mobility and balance were evaluated using a physical performance battery. Bone mineral density was screened using quantitative ultrasound (QUS). Associations between variables and falls grouping were analyzed using chi-square tests, t tests, and Mann-Whitney U tests, and effect sizes (ES) were calculated. Results. Thirty-four percent of PWH (median age, 36.6 years) reported falling during the past year, and 41.2% of fallers reported multiple falls. Fallers had more mobility problems (P = .013), higher fear of falling (P = .007), higher fracture history (P = .003), worse balance performance (P < .001), higher proportions of detectable viral loads (P = .021), and poorer bone quality (P = .040). Differences were of medium to large ES. Conclusions. This exploratory study is the first to show that relatively young South African PWH without obvious predisposing factors for gait and balance impairments experience falls. The observed fall-associated factors warrant further research using larger samples and longitudinal designs to ascertain fall predictors within this population.https://academic.oup.com/ofid/article/6/10/ofz401/5584296Publisher's versio

Physically active academic lessons; Acceptance, barriers and facilitators for implementation

Background To improve health and academic learning in schoolchildren, the Active School programme in Stavanger, Norway has introduced physically active academic lessons. This is a teaching method combining physical activity with academic content. The purpose of this paper was to evaluate the response to the physically active lessons and identify facilitators and barriers for implementation of such an intervention. Methods Five school leaders (principals or vice-principals), 13 teachers and 30 children from the five intervention schools were interviewed about their experiences with the 10-month intervention, which consisted of weekly minimum 2 × 45 minutes of physically active academic lessons, and the factors affecting its implementation. All interviews were transcribed and analysed using the qualitative data analysis program NVivo 10 (QSR international, London, UK). In addition, weekly teacher’s intervention delivery logs were collected and analysed. Results On average, the physically active academic lessons in 18 of the 34 weeks (53%) were reported in the teacher logs. The number of delivered physically active academic lessons covered 73% of the schools’ planned activity. Physically active lessons were well received among school leaders, teachers and children. The main facilitators for implementation of the physically active lessons were active leadership and teacher support, high self-efficacy regarding mastering the intervention, ease of organizing physically active lessons, inclusion of physically active lessons into the lesson curricula, and children’s positive reception of the intervention. The main barriers were unclear expectations, lack of knowledge and time to plan the physiclly active lessons, and the length of the physically active lessons (15–20 min lessons were preferred over the 45 min lessons). Conclusion Physically active academic lessons were considered an appropriate pedagogical method for creating positive variation, and were highly appreciated among both teachers and children. Both the principal and the teachers should be actively involved the implementation, which could be strengthened by including physical activity into the school’s strategy. Barriers for implementing physically active lessons in schools could be lowered by increasing implementation clarity and introducing the teachers to high quality and easily organized lessons.publishedVersio

Personal NO2 and volatile organic compounds exposure levels are associated with markers of cardiovascular risk in women in the Cape Town region of South Africa

CITATION: Everson, F., et al. 2019. Personal NO2 and volatile organic compounds exposure levels are associated with markers of cardiovascular risk in women in the Cape Town region of South Africa. International Journal of Environmental Research and Public Health, 16(13):2284, doi:10.3390/ijerph16132284.The original publication is available at http://www.mdpi.comENGLISH ABSTRACT: Exposure to ambient NO2 and benzene, toluene ethyl-benzene and m+p- and o-xylenes (BTEX) is associated with adverse cardiovascular effects, but limited information is available on the effects of personal exposure to these compounds in South African populations. This 6-month follow-up study aims to determine 7-day personal ambient NO2 and BTEX exposure levels via compact passive diffusion samplers in female participants from Cape Town, and investigate whether exposure levels are associated with cardiovascular risk markers. Overall, the measured air pollutant exposure levels were lower compared to international standards. NO2 was positively associated with systolic and diastolic blood pressure (SBP and DBP), and inversely associated with the central retinal venular equivalent (CRVE) and mean baseline brachial artery diameter. o-xylene was associated with DBP and benzene was strongly associated with carotid intima media thickness (cIMT). Our findings showed that personal air pollution exposure, even at relatively low levels, was associated with several markers of cardiovascular risk in women residing in the Cape Town region.https://www.mdpi.com/1660-4601/16/13/2284Publisher's versio

Relationship between Endothelial Function, Antiretroviral Treatment and Cardiovascular Risk Factors in HIV Patients of African Descent in South Africa: A Cross-Sectional Study

Limited information on the effect of antiretroviral treatment (ART) on vascular function in South Africans of African descent living with human immunodeficiency virus (HIV) is available. The relationship between ART, vascular function and cardiovascular risk factors in South Africans of African ancestry with HIV was therefore studied. This cross-sectional study recruited 146 HIV-positive individuals on ART (HIV+ART+), 163 HIV-positive individuals not on ART (HIV+ART−) and 171 individuals without HIV (HIV−) in Mthatha, Eastern Cape Province of South Africa. Flow-mediated dilation (FMD) test was performed to assess endothelial function. Anthropometry and blood pressure parameters were measured. Lipid profile, glycaemic indices, serum creatinine as well as CD4 count and viral load were assayed in blood. Urinary albumin to creatinine ratio (ACR) was determined as a marker of cardiovascular risk. Obesity and albuminuria were positively associated with HIV, and HIV+ART+ participants had significantly higher HDL cholesterol. Dyslipidaemia markers were significantly higher in hypertensive HIV+ART+ participants compared with the controls (HIV+ART− and HIV− participants). FMD was not different between HIV+ART+ participants and the controls. Moreover, HIV+ART+ participants with higher FMD showed lower total cholesterol and LDL cholesterol comparable to that of HIV− and HIV+ART− participants. A positive relationship between FMD and CD4 count was observed in HIV+ART+ participants. In conclusion, antiretroviral treatment was associated with cardiovascular risk factors, particularly dyslipidaemia, in hypertensive South Africans of African ancestry with HIV. Although, ART was not associated with endothelial dysfunction, flow-mediated dilatation was positively associated with CD4 count in HIV-positive participants on ART

SYNGAP1 encephalopathy:A distinctive generalized developmental and epileptic encephalopathy

Objective To delineate the epileptology, a key part of the SYNGAP1 phenotypic spectrum, in a large patient cohort. Methods Patients were recruited via investigators' practices or social media. We included patients with (likely) pathogenic SYNGAP1 variants or chromosome 6p21.32 microdeletions incorporating SYNGAP1. We analyzed patients' phenotypes using a standardized epilepsy questionnaire, medical records, EEG, MRI, and seizure videos. Results We included 57 patients (53% male, median age 8 years) with SYNGAP1 mutations (n = 53) or microdeletions (n = 4). Of the 57 patients, 56 had epilepsy: generalized in 55, with focal seizures in 7 and infantile spasms in 1. Median seizure onset age was 2 years. A novel type of drop attack was identified comprising eyelid myoclonia evolving to a myoclonic-atonic (n = 5) or atonic (n = 8) seizure. Seizure types included eyelid myoclonia with absences (65%), myoclonic seizures (34%), atypical (20%) and typical (18%) absences, and atonic seizures (14%), triggered by eating in 25%. Developmental delay preceded seizure onset in 54 of 56 (96%) patients for whom early developmental history was available. Developmental plateauing or regression occurred with seizures in 56 in the context of a developmental and epileptic encephalopathy (DEE). Fifty-five of 57 patients had intellectual disability, which was moderate to severe in 50. Other common features included behavioral problems (73%); high pain threshold (72%); eating problems, including oral aversion (68%); hypotonia (67%); sleeping problems (62%); autism spectrum disorder (54%); and ataxia or gait abnormalities (51%). Conclusions SYNGAP1 mutations cause a generalized DEE with a distinctive syndrome combining epilepsy with eyelid myoclonia with absences and myoclonic-atonic seizures, as well as a predilection to seizures triggered by eating.</p

Building on Progress Towards Fair Access : annual report 2019

Supplementary Table 3: Anti-epileptic drug use in patients with SYNGAP1 mutations or deletion