Doctor of Philosophy / Department of Anatomy and Physiology / Thomas J. Barstow / The overall aims of this dissertation are to determine the incidence and magnitude of insulin resistance (IR) in a cohort of normoglycemic college-age subjects with a family history of type 2 diabetes, and to ascertain if there is early macro- and microvascular dysfunction relative to IR. Study 1 (Chapter 2) revealed a 7-fold range in IR in healthy college subjects concomitant with measures of insulin, both fasted and during an oral glucose tolerance test, but not related with any measure of plasma glucose. These results emphasize that early in the etiology of carbohydrate dysregulation, abnormalities first occur with regard to insulin sensitivity. Using brachial artery blood flow (BABF, Doppler fluxometry) and near-infrared spectroscopy (NIRS) (Chapter 3) we extended the understanding of the use of these non-invasive tools to assess forearm resting metabolic rate and to compare the parameters of both the NIRS oxy-hemoglobin signal, as a index of perfusion in the microcirculation, and BABF, as an independent measure of microvascular reactivity during post occlusive reactive hyperemia (PORH). Resting metabolic rate ranged ~ 2 fold (2.83-5.15 [Mu]MO[subscript2]/min/100g) similar to direct measures. Amplitude, but not kinetic parameters for NIRS variables correlated with comparable parameters for BABF, providing evidence for the possible utility of NIRS in examining microvascular reactivity. In study 3 (Chapter 4), utilizing our extended understanding of hemodynamics garnered from the results of study 2, we assessed the influence of IR on macro- and microvascular reactivity. We observed that i) the magnitude of IR was significantly correlated with attenuation of endothelium-dependent vasodilation of the brachial artery (P< .01) indicating the possibility of a reduced nitric oxide bioavailability and an enhanced atherogenic milieu. Additionally we found ii) BABF at rest and during reactive hyperemia to be strongly correlated with conductance (reduced downstream resistance—an indicator of microvascular control abnormalities) independent of forearm metabolic rate, and iii) parameters of BABF (microvascular response) were also strongly correlated with brachial artery vasoreactivity (macrovascular response). In conclusion, this body of work furthers our insight into the need for earlier identification of "disease" earlier in the progression to type 2 diabetes, and provides direction for future investigations into prevention / intervention to improve microvessel functionality and to slow the atherosclerotic process in larger vessels.

L’augmentation constante de l’obésité dans les populations occidentales accroit la prévalence de nombreuses maladies liées au surpoids parmi lesquelles le syndrome d’apnées hypopnées du sommeil (SAHOS). Le SAHOS et l’obésité représentent deux facteurs de risque indépendants du développement de maladie cardiovasculaires (CV) et métaboliques. Etant souvent associés en pratique clinique, l’étude de leurs effets vasculaires et métaboliques spécifiques est difficile. Pour nous affranchir de cette problématique, nous avons étudié chez la souris, les effets respectifs et combinés d'un régime riche en graisse et/ou de 15 jours d'exposition à des conditions d'hypoxie intermittente (HI) mimant le SAHOS, sur les paramètres vasculaires et métaboliques. L’HI seule n'avait aucun impact sur le bilan-glucido lipidique, la fonction mitochondriale hépatique et la fonction vasculaire des animaux. Les animaux soumis au RRG présentaient une dyslipidémie,une stéatose hépatique, une dysfonction mitochondriale ainsi qu'une une dysfonction endothéliale. Lorsque l’HI était appliquée aux animaux recevant le RRG, l’ensemble de ces dysfonctions vasculaires, hépatiques et mitochondriales était prévenu mais une hyperinslinémie marquée était notée. Ce travail illustre les effets polymorphes de l’HI qui, pour des durées d’exposition courtes, pourrait présenter des effets bénéfiques sur les altérations associées à l’obésité qui contrastent avec les effets délétères à plus long terme décrits dans le SAHOS. / Decades increases the prevalence of many overweigh tassociated diseases including obstructive sleep apnea (OSA). Both OSA and obesity are considered as independent cardio-vascular and metabolic risk factors.The frequent association of OSA and obesity in clinical setting makes difficult to investigate their independent contribution to metabolic and vascular diseases. In the present thesis, we aimed to evaluate the impact of a short term intermittent hypoxia (IH), (animal model of OSA), of a high fat diet (HFD), and of both experimental conditions together (IH and HFD) on the vascular and metabolic outcomes. Short term IH alone had no impact on glucose and lipids levels and mitochondrial and vascular function. Animals fed with HFD presented dyslipidemia, hepatic steatosis, mitochondrial and endothelial dysfunction. Interestingly, when short term IH was applied to HFD fed mice, insulin level was increased, restored endothelial function and mitochondrial activity was restored and limited liver lipid accumulation was limited.Those data underline the polymorphic effects of IH that might target beneficial outcomes when applied for a short term in obesity, which contrast with the deleterious long term outcomes observed in OSA.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23075号 / 医博第4702号 / 新制||医||1049(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 川上 浩司, 教授 近藤 尚己, 教授 小川 修 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Purpose To evaluate the pelvic floor health knowledge base and presence of pelvic floor dysfunction (PFD) in women working in an office environment, and whether this knowledge significantly increases following a pelvic floor health education session and a re-education session. To assess whether this knowledge-acquisition leads to significant decrease in PFD. Participants Female volunteers (N=161), ages 18-69 years, were randomly allocated to Groups A, B or C. Methods Online surveys were completed by all groups on three occasions and included validated tools (Prolapse and Incontinence Knowledge Quiz, Pelvic Floor Distress Inventory-20, Pelvic Floor Impact Questionnaire-7) plus sexual function and pelvic floor muscle (PFM) exercise items. On completion of the baseline survey, an education session was given to Groups A and B only (Group C represented the controls). Following this, all participants completed the second survey. Two months later, to allow time for efficacy for the PFM exercises, a re-education presentation was given to Group A only, followed by the final survey administered to all. Analysis Of the 161 volunteers, 16 failed to complete all study requirements, leaving 145 questionnaires (Groups A and B n=48, Group C n=49) available for analysis using ANOVA and Descriptive Analysis. Results The knowledge base of the participants receiving the education showed highly significant improvement compared to the control group, and again for those receiving the re-education session. Although only 14% stated that they had PFD, the surveys revealed that 96% of the participants had PFD. The groups receiving the PFM exercise education and strategies to encourage healthier bladder and bowel habits showed significant decrease in PFD symptoms and increase in QoL. Education was successful in producing highly significant increases in knowledge, importance and commitment toward PFM exercise. Conclusion This study is unique as it evaluated pelvic floor health knowledge and presence of PFD of presumably healthy women within an office setting in contrast to patients seeking PFD medical attention. While further research is required, it is clear that low pelvic floor health knowledge was associated with high prevalence of PFD. Further, as knowledge/awareness significantly increased following education, so did QoL, while PFD significantly decreased.

Purpose To evaluate the pelvic floor health knowledge base and presence of pelvic floor dysfunction (PFD) in women working in an office environment, and whether this knowledge significantly increases following a pelvic floor health education session and a re-education session. To assess whether this knowledge-acquisition leads to significant decrease in PFD. Participants Female volunteers (N=161), ages 18-69 years, were randomly allocated to Groups A, B or C. Methods Online surveys were completed by all groups on three occasions and included validated tools (Prolapse and Incontinence Knowledge Quiz, Pelvic Floor Distress Inventory-20, Pelvic Floor Impact Questionnaire-7) plus sexual function and pelvic floor muscle (PFM) exercise items. On completion of the baseline survey, an education session was given to Groups A and B only (Group C represented the controls). Following this, all participants completed the second survey. Two months later, to allow time for efficacy for the PFM exercises, a re-education presentation was given to Group A only, followed by the final survey administered to all. Analysis Of the 161 volunteers, 16 failed to complete all study requirements, leaving 145 questionnaires (Groups A and B n=48, Group C n=49) available for analysis using ANOVA and Descriptive Analysis. Results The knowledge base of the participants receiving the education showed highly significant improvement compared to the control group, and again for those receiving the re-education session. Although only 14% stated that they had PFD, the surveys revealed that 96% of the participants had PFD. The groups receiving the PFM exercise education and strategies to encourage healthier bladder and bowel habits showed significant decrease in PFD symptoms and increase in QoL. Education was successful in producing highly significant increases in knowledge, importance and commitment toward PFM exercise. Conclusion This study is unique as it evaluated pelvic floor health knowledge and presence of PFD of presumably healthy women within an office setting in contrast to patients seeking PFD medical attention. While further research is required, it is clear that low pelvic floor health knowledge was associated with high prevalence of PFD. Further, as knowledge/awareness significantly increased following education, so did QoL, while PFD significantly decreased.

Tenofovir disoproxil fumarate (TDF) is a nucleotide reverse transcriptase inhibitor and a prodrug of tenofovir (TFV). It is the currently recommended first line combination treatment of human immunodeficiency virus (HIV) infection in adults. Various clinical studies have associated treatment with a TDF-containing antiretroviral therapy (ART) regimen with reduced bone mineral density (BMD) and renal dysfunction. Hardly any studies to date have correlated plasma TFV concentration with markers of renal function and bone turnover (BTM). This knowledge is also unavailable in the South African public health care system. Hence, the correlations between plasma TFV concentration and renal function markers and BTM in HIV-infected women were investigated. Renal function markers and BTM in HIV-infected women were compared with those in HIV-uninfected control women. A pilot cross-sectional sub-study within the Prospective Urban and Rural Epidemiology (PURE) South Africa study was conducted. Sixty women participated, of which 30 HIV-infected women were matched for age and body mass index with 30 HIV-uninfected ones. Ethics approval was obtained from the North-West University, Human Research Ethics committee (NWU-00016-10-A1) on 12 April 2013 to conduct this sub-study and the North West Department of Health, Mmabatho on 08 August 2013 to access patient health information. A validated high-performance liquid chromatography tandem mass spectrometry method was developed to analyse TFV in plasma. Renal markers measured were the estimated glomerular filtration rate (eGFR), creatinine clearance (CrCl), albuminuria, serum creatinine (SCr), serum urea, serum uric acid, glucosuria, urine sodium (UNa) and maximum tubular reabsorption of phosphate (TmPO4/GFR). The BTM markers measured included C-terminal telopeptide (CTx), alkaline phosphatase (ALP), parathyroid hormone (PTH), total vitamin D (VitD), serum calcium (SrCa), serum phosphate (SrP) and BMD. BMD was assessed using the DTX-200 peripheral DXA system (Osteometer MediTech, Hawthorn, California, USA). Renal and bone markers were analysed on Elecsys® 2010 and COBAS INTERGRA® 400 plus (Roche Diagnostics, Switzerland). Baseline data for HIV-infected participants with regard to CD4+ cell count, SCr prior to TDF initiation, time since TDF initiation, weight prior to TDF initiation and time since HIV diagnosis were collected retrospectively from participants’ public health care files. Statistical analyses applied were linear regression, analysis of covariance, the Mann-Whitney U test, paired t-test and unpaired t-test. IBM® SPSS® Statistics software 22 was used to perform all the statistical analyses. The median and interquartile range of plasma TFV concentration was 113 (74-139.4) ng/mL (n=25) and no TFV was detected in five participants’ plasma. Adjusted analyses showed TFV concentration to be associated with albuminuria (adjusted r2 = 0.339; p = 0.001). Values of CrCl, eGFR and albuminuria (p = 0.032; p = 0.038; p = 0.048, respectively) were significantly higher in HIV-infected women compared to HIV-uninfected women. CrCl [112 (84-137) mL/min] and eGFR [134 (93-153) mL/min/1.73m2] values were abnormally high in HIV-infected women. There was also an increase in both CrCl and eGFR (p = 0.008; p < 0.001, respectively) from baseline to median follow-up of 16.6 (8.8-23.4) months in HIV-infected women. At a TFV plasma concentration of ≥ 120 ng/mL, CTx and ALP correlated positively (r = 0.704; p = 0.016). ALP (112 ± 28 U/L; p < 0.001), CTx (0.68 ± 0.4 ng/mL; p = 0.027) and PTH (56.3 ± 32 pg/mL; p = 0.050) were higher in HIV-infected women compared to HIV-uninfected women. CD4+ cell count increased from baseline to follow-up in HIV-infected women (+250 cells/mm3; p = 0.001). In HIV-infected women on a TDF-based regimen, TFV plasma concentration is associated with an increase in albuminuria, while perturbations in BTM equilibrium occur at ≥ 120 ng/mL of TFV plasma concentration. Abnormally higher CrCl and eGFR are present in HIV-infected women, seen as glomerular hyperfiltration compared with HIV-uninfected women. There was immunological improvement with TDF-based ART in HIV-infected women. Longitudinal studies with larger sample sizes are needed to confirm these findings. / MSc (Pharmacology), North-West University, Potchefstroom Campus, 2015

Tenofovir disoproxil fumarate (TDF) is a nucleotide reverse transcriptase inhibitor and a prodrug of tenofovir (TFV). It is the currently recommended first line combination treatment of human immunodeficiency virus (HIV) infection in adults. Various clinical studies have associated treatment with a TDF-containing antiretroviral therapy (ART) regimen with reduced bone mineral density (BMD) and renal dysfunction. Hardly any studies to date have correlated plasma TFV concentration with markers of renal function and bone turnover (BTM). This knowledge is also unavailable in the South African public health care system. Hence, the correlations between plasma TFV concentration and renal function markers and BTM in HIV-infected women were investigated. Renal function markers and BTM in HIV-infected women were compared with those in HIV-uninfected control women. A pilot cross-sectional sub-study within the Prospective Urban and Rural Epidemiology (PURE) South Africa study was conducted. Sixty women participated, of which 30 HIV-infected women were matched for age and body mass index with 30 HIV-uninfected ones. Ethics approval was obtained from the North-West University, Human Research Ethics committee (NWU-00016-10-A1) on 12 April 2013 to conduct this sub-study and the North West Department of Health, Mmabatho on 08 August 2013 to access patient health information. A validated high-performance liquid chromatography tandem mass spectrometry method was developed to analyse TFV in plasma. Renal markers measured were the estimated glomerular filtration rate (eGFR), creatinine clearance (CrCl), albuminuria, serum creatinine (SCr), serum urea, serum uric acid, glucosuria, urine sodium (UNa) and maximum tubular reabsorption of phosphate (TmPO4/GFR). The BTM markers measured included C-terminal telopeptide (CTx), alkaline phosphatase (ALP), parathyroid hormone (PTH), total vitamin D (VitD), serum calcium (SrCa), serum phosphate (SrP) and BMD. BMD was assessed using the DTX-200 peripheral DXA system (Osteometer MediTech, Hawthorn, California, USA). Renal and bone markers were analysed on Elecsys® 2010 and COBAS INTERGRA® 400 plus (Roche Diagnostics, Switzerland). Baseline data for HIV-infected participants with regard to CD4+ cell count, SCr prior to TDF initiation, time since TDF initiation, weight prior to TDF initiation and time since HIV diagnosis were collected retrospectively from participants’ public health care files. Statistical analyses applied were linear regression, analysis of covariance, the Mann-Whitney U test, paired t-test and unpaired t-test. IBM® SPSS® Statistics software 22 was used to perform all the statistical analyses. The median and interquartile range of plasma TFV concentration was 113 (74-139.4) ng/mL (n=25) and no TFV was detected in five participants’ plasma. Adjusted analyses showed TFV concentration to be associated with albuminuria (adjusted r2 = 0.339; p = 0.001). Values of CrCl, eGFR and albuminuria (p = 0.032; p = 0.038; p = 0.048, respectively) were significantly higher in HIV-infected women compared to HIV-uninfected women. CrCl [112 (84-137) mL/min] and eGFR [134 (93-153) mL/min/1.73m2] values were abnormally high in HIV-infected women. There was also an increase in both CrCl and eGFR (p = 0.008; p < 0.001, respectively) from baseline to median follow-up of 16.6 (8.8-23.4) months in HIV-infected women. At a TFV plasma concentration of ≥ 120 ng/mL, CTx and ALP correlated positively (r = 0.704; p = 0.016). ALP (112 ± 28 U/L; p < 0.001), CTx (0.68 ± 0.4 ng/mL; p = 0.027) and PTH (56.3 ± 32 pg/mL; p = 0.050) were higher in HIV-infected women compared to HIV-uninfected women. CD4+ cell count increased from baseline to follow-up in HIV-infected women (+250 cells/mm3; p = 0.001). In HIV-infected women on a TDF-based regimen, TFV plasma concentration is associated with an increase in albuminuria, while perturbations in BTM equilibrium occur at ≥ 120 ng/mL of TFV plasma concentration. Abnormally higher CrCl and eGFR are present in HIV-infected women, seen as glomerular hyperfiltration compared with HIV-uninfected women. There was immunological improvement with TDF-based ART in HIV-infected women. Longitudinal studies with larger sample sizes are needed to confirm these findings. / MSc (Pharmacology), North-West University, Potchefstroom Campus, 2015

Cognitive impairment in amyotrophic lateral sclerosis (ALS) is characterized by deficits on tests of executive functions however the contribution of processing speed is unknown. By contrast, multiple sclerosis (MS) is a disorder in which slowed processing speed is regarded as the core deficit, however, methodology is often confounded by tasks which depend on motor speed. MRI studies have revealed multi-system cerebral involvement in ALS, with evidence of reduced white matter volume and integrity in predominantly frontotemporal regions. The current study had two aims. Firstly, to investigate whether cognitive impairments in ALS and MS are due to executive dysfunction or slowed processing speed, independent of motor dysfunction. Secondly, to investigate the relationship between specific cognitive impairments and the integrity of distinct white matter tracts in ALS. Twenty-nine ALS patients, twenty-five MS patients, and matched healthy control groups were administered a dual task paradigm and processing speed tasks in which stimulus presentation times were manipulated. In addition background measures of executive functioning, working memory, verbal memory, and language were administered. White matter integrity was investigated using region-of-interest (ROI) and tract based spatial statistics (TBSS) analyses of diffusion MRI data. ALS patients did not show impairments in tests of processing speed, but deficits were revealed in the dual task, as well as background tests of executive functioning, working memory, and verbal memory. MS patients also exhibited deficits in the dual task as well as background tests of executive functioning, working memory, and verbal memory. However, in contrast to ALS patients, a processing speed deficit was also observed in MS. ROI analyses revealed significant differences in fractional anisotropy (FA) and mean diffusivity (<D>) between ALS patients and healthy controls. Reduced integrity was observed in the corticospinal tracts and prefrontal and temporal white matter tracts including uncinate fasciculus, inferior longitudinal fasciculus, and regions of the cingulum. Significant differences also emerged in the white matter underlying the superior, medial and inferior frontal gyri, and the temporal gyri. Similar group differences were found in the TBSS analyses; ALS patients displayed prominent changes in the corticospinal tract and corpus callosum as well as extensive changes in prefrontal and temporal tracts and association fibres. Correlations between task performance and ROI parameters revealed that dual task performance was associated with FA in the middle frontal gyrus white matter while letter fluency indices correlated with FA in the corpus callosum and corticospinal tracts. Furthermore, verbal memory performance correlated with FA in the inferior longitudinal fasciculus and working memory performance correlated with <D> in uncinate fasciculus and hippocampal portion of the cingulum. Correlations with TBSS revealed significant associations between letter fluency indices and FA in the corticospinal tracts and anterior corpus callosum. The current study demonstrates that cognitive impairment in ALS is not due to slowed processing speed. Moreover dual task deficits are related to distinct prefrontal tract involvement in ALS, whilst fluency deficits may reflect decreasing callosal integrity. Deficits in working memory and verbal memory are related to white matter changes in fibre bundles connecting prefrontal, temporal, and limbic structures.

<p>Mitochondria are responsible for producing the vast majority of cellular ATP, and are therefore critical to organismal health [1]. They contain thir own genomes (mtDNA) which encode 13 proteins that are all subunits of the mitochondrial respiratory chain (MRC) and are essential for oxidative phosphorylation [2]. mtDNA is present in multiple copies per cell, usually between 103 and 104 , though this number is reduced during certain developmental stages [3, 4]. The health of the mitochondrial genome is also important to the health of the organism, as mutations in mtDNA lead to human diseases that collectively affect approximately 1 in 4000 people [5, 6]. mtDNA is more susceptible than nuclear DNA (nucDNA) to damage by many environmental pollutants, for reasons including the absence of Nucleotide Excision Repair (NER) in the mitochondria [7]. NER is a highly functionally conserved DNA repair pathway that removes bulky, helix distorting lesions such as those caused by ultraviolet C (UVC) radiation and also many environmental toxicants, including benzo[a]pyrene (BaP) [8]. While these lesions cannot be repaired, they are slowly removed through a process that involves mitochondrial dynamics and autophagy [9, 10]. However, when present during development in C. elegans, this damage reduces mtDNA copy number and ATP levels [11]. We hypothesize that this damage, when present during development, will result in mitochondrial dysfunction and increase the potential for adverse outcomes later in life.</p><p>To test this hypothesis, 1st larval stage (L1) C. elegans are exposed to 3 doses of 7.5J/m2 ultraviolet C radiation 24 hours apart, leading to the accumulation of mtDNA damage [9, 11]. After exposure, many mitochondrial endpoints are assessed at multiple time points later in life. mtDNA and nucDNA damage levels and genome copy numbers are measured via QPCR and real-time PCR , respectively, every 2 day for 10 days. Steady state ATP levels are measured via luciferase expressing reporter strains and traditional ATP extraction methods. Oxygen consumption is measured using a Seahorse XFe24 extra cellular flux analyzer. Gene expression changes are measured via real time PCR and targeted metabolomics via LC-MS are used to investigate changes in organic acid, amino acid and acyl-carnitine levels. Lastly, nematode developmental delay is assessed as growth, and measured via imaging and COPAS biosort.</p><p>I have found that despite being removed, UVC induced mtDNA damage during development leads to persistent deficits in energy production later in life. mtDNA copy number is permanently reduced, as are ATP levels, though oxygen consumption is increased, indicating inefficient or uncoupled respiration. Metabolomic data and mutant sensitivity indicate a role for NADPH and oxidative stress in these results, and exposed nematodes are more sensitive to the mitochondrial poison rotenone later in life. These results fit with the developmental origin of health and disease hypothesis, and show the potential for environmental exposures to have lasting effects on mitochondrial function.</p><p>Lastly, we are currently working to investigate the potential for irreparable mtDNA lesions to drive mutagenesis in mtDNA. Mutations in mtDNA lead to a wide range of diseases, yet we currently do not understand the environmental component of what causes them. In vitro evidence suggests that UVC induced thymine dimers can be mutagenic [12]. We are using duplex sequencing of C. elegans mtDNA to determine mutation rates in nematodes exposed to our serial UVC protocol. Furthermore, by including mutant strains deficient in mitochondrial fission and mitophagy, we hope to determine if deficiencies in these processes will further increase mtDNA mutation rates, as they are implicated in human diseases.</p> / Dissertation

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Diabetes is considered a major threat to human health in both developed and developing nations. Cardiovascular disease which is common in diabetic patients has increased the overall disease affliction. Moreover, stress-induced hyperglycemia has led to increased mortality and morbidity in patients with an acute myocardial infarction (MI), whether the patient has diabetes or not. In addition, acute MI might stem from stress-induced hyperglycemia capability to increase inflammation and oxidative stress resulting in a worse functional cardiac outcome. Hyperglycemia-induced oxidative stress can similarly result in the formation of miss folded or damaged proteins that may be eliminated by the ubiquitin-proteasome system (UPS). Futhermore, hyperglycemia-induced oxidative stress can also result in dysregulation of the UPS that removes these misfolded proteins. Additionally, an increasing body of evidence implicates UPS dysfunction in cardiac diseases and hyperglycemia which has been associated with increased inflammation and blunted cardiac function in response to ischemia-reperfusion. Literature however is blurred whether a reduction or a rise in the UPS is damaging with hyperglycemia and in response to ischemia-reperfusion. In light of this, we hypothesized that UPS inhibitors such as Z-Leu-Leu-Leu-al (MG-132) and lactacystin, protects the rat heart against ischemia-reperfusion under hyperglycemic perfusion conditions. Isolated rat hearts were perfused ex vivo with Krebs-Henseleit buffer containing 33 mM glucose vs. controls (11 mM glucose) for 60 min, followed by 20 min global ischemia and 60 minutes reperfusion ± PI treatment (MG-132 and lactacystin), anti-inflammatory (Ibuprofen) and anti-oxidant (NAC). Infarct size was determined using Evans Blue dye and 1% 2,3,5-triphenyl tetrazolium chloride (TTC) staining with 20 minutes regional ischemia and 2 hours reperfusion ± PI’s treatments. Tissues were collected at the end of the global ischemia experiments and analyzed for UPS activity, oxidative stress, apoptosis and inflammation. Our data expressed a reduced cardiac contractile function in response to ischemia and reperfusion under hyperglycemic conditions as well as an increase in UPS activity. PI treatment resulted in cardio-protection for ex vivo rat heart model exposed to ischemia and reperfusion under hyperglycemic conditions as well as ibuprofen and NAC. In parallel lactacystin treatment significantly decreased myocardial oxidative stress, apoptosis, and inflammation which provided cardio-protection in response to ischemia and reperfusion under hyperglycemic conditions This study shows that acute hyperglycemia elicits myocardial oxidative stress, apoptosis and inflammation that in time results in an increase in contractile dysfunction following ischemia and reperfusion. However, we found that PI treatment with both MG-132 and lactacystin blunted high glucose-induced damaging effects which resulted in a robust cardio-protection in response to ischemia and reperfusion under hyperglycemic conditions, by reducing oxidative stress, decreasing apoptosis and limiting inflammation. A parallel outcome was observed at baseline although the underlying mechanisms driving this process still need to be clarified. Our findings indicate that the UPS may be a unique therapeutic target to treat ischemic heart disease in diabetic patients, and non-diabetic individuals that present with stress-induced hyperglycemia. In summary, this thesis established that PIs act as a novel cardio-protective intervention to treat acute hyperglycemia with associated cardiovascular complications. / AFRIKAANSE OPSOMMING: Diabeties word beskou as ‘n baie groot problem vir menslieke gesondhied vir biede die ontwikkel en onontwikkelende lande. Kardiovaskulêre siekte wat normaal met diabetiese pasiente geassoseerd word veroorsaak ‘n toeneemende druk, wat hierdie siekte laat toeneem. Verder meer vergroot stresgeïnduseerde hiperglukemie die mortaliteit van pasiente met of sonder diabeties wat akute miokardiale infarksie onder lede het. Akute miokardiale infarksie kan ook ontstaan van stresgeïnduseerde hiperglukemie se bekwaamheid om meer inflamasie en oksidante stress te veroorsaak wat in ‘n meer swakker funksionele kardiale toestand. Hiperglukemiegeïnduseerde oksidatiewe stres ook tot wanregulering van die ubikwitien-proteosoomsisteem (UPS) wat wangevoude protïene verwyder, aanleiding gee. Kontrasterende data bestaan van verhoogde/verlaagde UPS aktiwietiet, sowel as met hiperglukemie en/of in reaksie tot isgemie-reperfussie. As gewolg hiervan,, hipotetiseer ons dat Z-Leu-Leu-Leu-al (MG-132) and lactacystin as ‘n nuwe kardiobeskermingsmiddel kan optree deur miokardiale oksidatiewe stress, inflamasie en UPS aktiwiteit te verlaag in reaksie op isgemie-reperfussie tydens akute hiperglukemiese toestande kan verlaag. Geïsoleerde rotharte is ex vivo met Krebs-Henseleit buffer, wat, 33 mM glukose vs. kontrole (11 mM glukose) bevat, vir 60 min geperfuseer, daarna is dit deur 20 min globale isgemie gevolg en 60 min reperfussie ± PI behandeling (MG-132 and lactacystin), antiflammatoriese behandeling (Ibuprofen) en antioxidant behandeling (NAC). Infarkgrootte is bepaal deur Evans bou kleursel en 1% 2. 3-5 tripfeniel tetrazoloimcholierd (TTC) kleuring met 20 minute regionale ischemie, en 2 uur reprefussie ± PI’s behandeling. Weefsels is aan die einde van die globale isgemie eksperimente versamel, en vir oksidatewe stres, apoptose en inflammasie ontleed. Ons data toon aan dat kardiale kontraktiele funksie in reaksie op isgemie-reperfussie onder hiperglukemiese toestande verlaag het asook ‘n toename in UPS aktiwitiet veroorsaak. PI behandeling het gelei tot kardiale beskerming vir ex vivo rotharte wat aan isgemie-reperfussie onder hiperglukemiese toestande blootgestel was sowel as ibuprofen en NAC. Parallel hiermee het lactacystin oksidatiewe stres, apoptose, inflmasie, en UPS aktiwiteit na isgemie-reperfussie, verlaag in reaksie isgemie-reperfussie onder hiperglukemiese toestande. Hierdie studie het bevind dat akute hiperglukemie, miokardiale oksidatiewe stres lei tot oksidante stress, apoptose, en inflamasie na kontraktiele wanfunksionering na isgemie-reperfussie lei. Ons het bevind dat beide MG-132 en lactacystin behandeling, hoë glukose-geïnduseerde skadelike effekte onderdruk, en kardiale-beskerming in reaksie op isgemie-reperfussie onder hiperglukemiese toestande ondervind was deur oksidante stress, apoptose, en inflamasie te verlaag. ‘n Soorgelyke effek is tydens die basislyn waargeneem, alhoewel die onderliggende meganisme wat hierdie proses meer ondersoek instel. Ons bevinding dei dat die UPS ‘n nuwe behandeling teiken kan word in sgemie-geïnduseerde reperfussie onder aktute en chroniese hoë glukose toestande. In opsomming, het die tesis belowend bevindinge gevind wat ‘n nuwe terapeutiese intervensie vir die behandeling van akute hiperglukemie met geassosieërde kardiovaskulêre komplikasies gebruik kan word.