Showing items 1 - 9 of 9

Consumption of a low glycaemic index diet in late life extends lifespan of Nalb/c mice with differential effects on DNA damage

- Nankervis, Scott, Mitchell, Jenée, Charchar, Fadi, McGlynn, Maree, Lewandowski, Paul

  • Authors: Nankervis, Scott , Mitchell, Jenée , Charchar, Fadi , McGlynn, Maree , Lewandowski, Paul
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Longevity & Healthspan. 2(4) p. 1-13
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  • Description: Background Caloric restriction is known to extend the lifespan of all organisms in which it has been tested. Consequently, current research is investigating the role of various foods to improve health and lifespan. The role of various diets has received less attention however, and in some cases may have more capacity to improve health and longevity than specific foods alone. We examined the benefits to longevity of a low glycaemic index (GI) diet in aged Balb/c mice and examined markers of oxidative stress and subsequent effects on telomere dynamics. Results In an aged population of mice, a low GI diet extended average lifespan by 12%, improved glucose tolerance and had impressive effects on amelioration of oxidative damage to DNA in white blood cells. Telomere length in quadriceps muscle showed no improvement in the dieted group, nor was telomerase reactivated. Conclusion The beneficial effects of a low GI diet are evident from the current study and although the impact to telomere dynamics late in life is minimal, we expect that earlier intervention with a low GI diet would provide significant improvement in health and longevity with associated effects to telomere homeostasis.

Dysregulation of c-kit expression parallels the development of spontaneous genetic cardiac hypertrophy

- Marques, Francine, Prestes, Priscilla, Lewandowski, Paul, Harrap, Stephen, Charchar, Fadi

  • Authors: Marques, Francine , Prestes, Priscilla , Lewandowski, Paul , Harrap, Stephen , Charchar, Fadi
  • Date: 2015
  • Type: Text , Conference paper
  • Relation: Cardiac Society of Australia and New Zealand Annual Scientific Meeting and the International Society for Heart Research Australasian Section Annual Scientific Meeting; Melbourne, Victoria, Australia; 13th-16th August 2016; published in Heart, Lung and Circulation. Vol. 24, p. S401-S401
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  • Description: Objective: The molecular processes associated with cardiac hypertrophy independent of blood pressure are still largely unknown. The hypertrophic heart rate (HHR) is normotensive and born with a reduced complement of cardiomyocytes that predisposes to cardiac hypertrophy and failure in later life. We investigated the expression of c-kit gene, a marker of cardiac stem cells and myocardial regeneration that could contribute to hypertrophy. Methods: Left ventricular c-kit mRNA expression was measured by real-time PCR in HHR and control strain in neonatal and 38-week old rats (n=7-12/group). We tested for linkage of c-kit expression with neonatal cardiac size in 197 second generation crosses (F2) of HHR and control strain. Results: c-kit mRNA was slightly up-regulated in neonatal (fold change +1.3, P=0.02) and markedly so in 38-week old HHR (+35.5, P=0.0003). Cardiac weight index was positively correlated with neonatal myocardial c-kit mRNA in the F2 population (r=0.19, P=0.007). Conclusions: In HHR hearts c-kit expression appears increased throughout life, but more so in the adult where cardiac hypertrophy is established and leading to failure. In aged hypertrophic hearts, over-expression of c-kit is likely a compensatory mechanism of the failing heart. Previous studies showed an activation of cardiac stem cells in the hypertrophic myocardium. Our study suggests that c-kit might be involved from an early age in mechanisms that lead to cardiac hypertrophy in adulthood.

Experimental and human evidence for Lipocalin-2 (Neutrophil Gelatinase-Associated Lipocalin NGAL ) in the development of cardiac hypertrophy and heart failure

- Marques, Francine, Prestes, Priscilla, Byars, Sean, Ritchie, Scott, Wurtz, Peter, Patel, Sheila, Booth, Scott, Rana, Indrajeetsinh, Minoda, Yosuke, Berzins, Stuart, Curl, Claire, Bell, James, Wai, Bryan, Srivastava, Piyush, Kangas, Antti, Soininen, Pasi, Ruohonen, Saku, Kahonen, Mika, Lehtimaki, Terho, Raitoharju, Emma, Havulinna, Aki, Perola, Markus, Raitakari, Olli, Salomaa, Veikko, Ala-Korpela, Mika, Kettunen, Johannes, McGlynn, Maree, Kelly, Jason, Wlodek, Mary, Lewandowski, Paul, Delbridge, Lea, Burrell, Louise, Inouye, Michael, Harrap, Stephen, Charchar, Fadi

Involvement of human monogenic cardiomyopathy genes in experimental polygenic cardiac hypertrophy

- Prestes, Priscilla, Marques, Francine, Lopez-Campos, Guillermo, Lewandowski, Paul, Delbridge, Lea, Charchar, Fadi, Harrap, Stephen

  • Authors: Prestes, Priscilla , Marques, Francine , Lopez-Campos, Guillermo , Lewandowski, Paul , Delbridge, Lea , Charchar, Fadi , Harrap, Stephen
  • Date: 2018
  • Type: Text , Journal article
  • Relation: Physiological Genomics Vol. 50, no. 9 (2018), p. 680-687
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  • Description: Hypertrophic cardiomyopathy thickens heart muscles, reducing functionality and increasing risk of cardiac disease and morbidity. Genetic factors are involved, but their contribution is poorly understood. We used the hypertrophic heart rat (HHR), a unique normotensive polygenic model of cardiac hypertrophy and heart failure, to investigate the role of genes associated with monogenic human cardiomyopathy. We selected 42 genes involved in monogenic human cardiomyopathies to study: 1) DNA variants, by sequencing the whole genome of 13-wk-old HHR and age-matched normal heart rat (NHR), its genetic control strain; 2) mRNA expression, by targeted RNA-sequencing in left ventricles of HHR and NHR at 5 ages (2 days old and 4, 13, 33, and 50 wk old) compared with human idiopathic dilated cardiomyopathy data; and 3) microRNA expression, with rat microRNA microarrays in left ventricles of 2-day-old HHR and age-matched NHR. We also investigated experimentally validated microRNA-mRNA interactions. Whole-genome sequencing revealed unique variants mostly located in noncoding regions of HHR and NHR. We found 29 genes differentially expressed in at least 1 age. Genes encoding desmoglein 2 (Dsg2) and transthyretin (Ttr) were significantly differentially expressed at all ages in the HHR, but only Ttr was also differentially expressed in human idiopathic cardiomyopathy. Lastly, only two microRNAs differentially expressed in the HHR were present in our comparison of validated microRNA-mRNA interactions. These two microRNAs interact with five of the genes studied. Our study shows that genes involved in monogenic forms of human cardiomyopathies may also influence polygenic forms of the disease.

MicroRNA-34a and tert act as epi-drivers of cardiac telomere length and polygenic cardiac hypertrophy

- Booth, Scott, Marques, Francine, Prestes, Priscilla, Curl, Claire, Delbridge, Lea, Lewandowski, Paul, Harrap, Stephen, Charchar, Fadi

  • Authors: Booth, Scott , Marques, Francine , Prestes, Priscilla , Curl, Claire , Delbridge, Lea , Lewandowski, Paul , Harrap, Stephen , Charchar, Fadi
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Heart, Lung and Circulation Vol. 24, no. S3 (2015), p. S180-S181
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  • Description: Cardiac hypertrophy is one of the main risk factors forheart failure. Here we aimed to investigate whether cardiactelomere length contributes to polygenic cardiac hypertro-phy independent of blood pressure. We also investigatedwhether changes in telomere length were due to the telomereregulators microRNA-34a,Ppp1r10(also known asPnuts)and telomerase. We used the hypertrophic heart rat (HHR),a normotensive model of polygenetic cardiac hypertrophy,and compared it to age-matched controls. Telomere length, microRNA levels, gene expression and telomerase activitywere measured in isolated cardiomyocytes and left ventricletissue using real-time PCR. Telomere length was significantlylonger in 2-day and 38-week-old HHR, but shorter at 4-and 13-week HHR. In the HHR, telomere length becameshorter early in development, while in the control straintelomere shortening was only observed in late adulthood.Telomere length was the main determinant of cardiac mass.

MicroRNAs in a hypertrophic heart : From foetal life to adulthood

- Sadiq, Shahzad, Crowley, Tamsyn, Charchar, Fadi, Sanigorski, Andrew, Lewandowski, Paul

  • Authors: Sadiq, Shahzad , Crowley, Tamsyn , Charchar, Fadi , Sanigorski, Andrew , Lewandowski, Paul
  • Date: 2017
  • Type: Text , Journal article
  • Relation: Biological Reviews Vol. 92, no. 3 (2017), p. 1314-1331
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  • Description: The heart is the first organ to form and undergoes adaptive remodelling with age. Ventricular hypertrophy is one such adaptation, which allows the heart to cope with an increase in cardiac demand. This adaptation is necessary as part of natural growth from foetal life to adulthood. It may also occur in response to resistance in blood flow due to various insults on the heart and vessels that accumulate with age. The heart can only compensate to this increase in workload to a certain extent without losing its functional architecture, ultimately resulting in heart failure. Many genes have been implicated in cardiac hypertrophy, however none have been shown conclusively to be responsible for pathological cardiac hypertrophy. MicroRNAs offer an alternative mechanism for cellular regulation by altering gene expression. Since 1993 when the function of a non-coding DNA sequence was first discovered in the model organism Caenorhabditis elegans, many microRNAs have been implicated in having a central role in numerous physiological and pathological cellular processes. The level of control these antisense oligonucleotides offer can often be exploited to manipulate the expression of target genes. Moreover, altered levels of microRNAs can serve as diagnostic biomarkers, with the prospect of diagnosing a disease process as early as during foetal life. Therefore, it is vital to ascertain and investigate the function of microRNAs that are involved in heart development and subsequent ventricular remodelling. Here we present an overview of the complicated network of microRNAs and their target genes that have previously been implicated in cardiogenesis and hypertrophy. It is interesting to note that microRNAs in both of these growth processes can be of possible remedial value to counter a similar disease pathophysiology.

Salt Loading in Canola Oil Fed SHRSP Rats Induces Endothelial Dysfunction

- Papazzo, Annateresa, Conlan, Xavier, Lexis, Louise, Charchar, Fadi, Lewandowski, Paul

  • Authors: Papazzo, Annateresa , Conlan, Xavier , Lexis, Louise , Charchar, Fadi , Lewandowski, Paul
  • Date: 2013
  • Type: Text , Journal article
  • Relation: PLoS ONE Vol. 8, no. 6 (2013), p.
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  • Description: This study aimed to determine if 50 days of canola oil intake in the absence or presence of salt loading affects: (1) antioxidant and oxidative stress markers, (2) aortic mRNA of NADPH oxidase (NOX) subunits and superoxide dismutase (SOD) isoforms and (3) endothelial function in SHRSP rats. SHRSP rats were fed a diet containing 10 wt/wt% soybean oil or 10 wt/wt% canola oil, and given tap water or water containing 1% NaCl for 50 days. Without salt, canola oil significantly increased RBC SOD, plasma cholesterol and triglycerides, aortic p22phox, NOX2 and CuZn-SOD mRNA, and decreased RBC glutathione peroxidase activity. With salt, canola oil reduced RBC SOD and catalase activity, LDL-C, and p22phox mRNA compared with canola oil alone, whereas plasma malondialdehyde (MDA) was reduced and RBC MDA and LDL-C were higher. With salt, the canola oil group had significantly reduced endothelium-dependent vasodilating responses to ACh and contractile responses to norepinephrine compared with the canola oil group without salt and to the WKY rats. These results indicate that ingestion of canola oil increases O2 - generation, and that canola oil ingestion in combination with salt leads to endothelial dysfunction in the SHRSP model. © 2013 Papazzo et al.
  • Description: 2003011096

Telomere dynamics during aging in polygenic left ventricular hypertrophy

- Marques, Francine, Booth, Scott, Prestes, Priscilla, Curl, Claire, Delbridge, Lea, Lewandowski, Paul, Harrap, Stephen, Charchar, Fadi

  • Authors: Marques, Francine , Booth, Scott , Prestes, Priscilla , Curl, Claire , Delbridge, Lea , Lewandowski, Paul , Harrap, Stephen , Charchar, Fadi
  • Date: 2016
  • Type: Text , Journal article
  • Relation: Physiological Genomics Vol. 48, no. 1 (2016), p. 42-49
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  • Description: Short telomeres are associated with increased risk of cardiovascular disease. Here we studied cardiomyocyte telomere length at key ages during the ontogeny of cardiac hypertrophy and failure in the hypertrophic heart rat (HHR) and compared these with the normal heart rat (NHR) control strain. Key ages corresponded with the pathophysiological sequence beginning with fewer cardiomyocytes (2 days), leading to left ventricular hypertrophy (LVH) (13 wk) and subsequently progression to heart failure (38 wk). We measured telomere length, tissue activity of telomerase, mRNA levels of telomerase reverse transcriptase (Tert) and telomerase RNA component (Terc), and expression of the telomeric regulator microRNA miR-34a. Cardiac telomere length was longer in the HHR compared with the control strain at 2 days and 38 wk, but shorter at 13 wk. Neonatal HHR had higher cardiac telomerase activity and expression of Tert and miR-34a. Telomerase activity was not different at 13 or 38 wk. Tert mRNA and Terc RNA were overexpressed at 38 wk, while miR-34a was overexpressed at 13 wk but downregulated at 38 wk. Circulating leukocytes were strongly correlated with cardiac telomere length in the HHR only. The longer neonatal telomeres in HHR are likely to reflect fewer fetal and early postnatal cardiomyocyte cell divisions and explain the reduced total cardiomyocyte complement that predisposes to later hypertrophy and failure. Although shorter telomeres were a feature of cardiac hypertrophy at 13 wk, they were not present at the progression to heart failure at 38 wk. © 2016 the American Physiological Society.

Tripartite motif-containing 55 identified as functional candidate for spontaneous cardiac hypertrophy in the rat locus cardiac mass 22

- Prestes, Priscilla, Marques, Francine, Lopez-Campos, Guillermo, Booth, Scott, McGlynn, Maree, Lewandowski, Paul, Delbridge, Lea, Harrap, Stephen, Charchar, Fadi

  • Authors: Prestes, Priscilla , Marques, Francine , Lopez-Campos, Guillermo , Booth, Scott , McGlynn, Maree , Lewandowski, Paul , Delbridge, Lea , Harrap, Stephen , Charchar, Fadi
  • Date: 2016
  • Type: Text , Journal article
  • Relation: Journal of Hypertension Vol. 34, no. 5 (May 2016), p. 950-958
  • Relation: http://purl.org/au-research/grants/nhmrc/1034371
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  • Description: Background:Left ventricular (LV) hypertrophy is a risk factor for cardiovascular death, but the genetic factors determining LV size and predisposition to hypertrophy are not well understood. We have previously linked the quantitative trait locus cardiac mass 22 (Cm22) on chromosome 2 with cardiac hypertrophy independent of blood pressure in the spontaneously hypertensive rat. From an original cross of spontaneously hypertensive rat with F344 rats, we derived a normotensive polygenic model of spontaneous cardiac hypertrophy, the hypertrophic heart rat (HHR) and its control strain, the normal heart rat (NHR).Methods and results:To identify the genes and molecular mechanisms underlying spontaneous LV hypertrophy we sequenced the HHR genome with special focus on quantitative trait locus Cm22. For correlative analyses of function, we measured global RNA transcripts in LV of neonatal HHR and NHR and 198 neonatal rats of an HHRxNHR F2 crossbred population. Only one gene within locus Cm22 was differentially expressed in the parental generation: tripartite motif-containing 55 (Trim55), with mRNA downregulation in HHR (P<0.05) and reduced protein expression. Trim55 mRNA levels were negatively correlated with LV mass in the F2 cross (r=-0.16, P=0.025). In exon nine of Trim55 in HHR, we found one missense mutation that functionally alters protein structure. This mutation was strongly associated with Trim55 mRNA expression in F2 rats (F=10.35, P<0.0001). Similarly, in humans, we found reduced Trim55 expression in hearts of subjects with idiopathic dilated cardiomyopathy.Conclusion:Our study suggests that the Trim55 gene, located in Cm22, is a novel candidate gene for polygenic LV hypertrophy independent of blood pressure.
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