Heterogeneous distribution of a fatty acid analogue uptake in the myocardium of aged rats

1994 ◽  
Vol 72 (10) ◽  
pp. 1120-1126 ◽  
Author(s):  
Catherine Communal ◽  
Jean Verdetti ◽  
Colette Estrade ◽  
Thierry Humbert ◽  
Pierre Demenge

The aim of this study was to determine the extent and location of damaged myocardial areas in senescent rats. The viability of myocardial cells was evaluated in virgin young (4 months old) and aged (29 months old) female Wistar rats by analysing the uptake of a slowly metabolisable radiolabelled fatty acid analogue, 15-p-iodophenyl-β-methylpentadecanoic acid (IMPPA). The biodistribution of IMPPA was measured in various organs, and regional myocardial uptake was specifically assessed using quantitative autoradiography. Myocardial enzymatic activity and DNA content were also evaluated with nitro blue tetrazolium (NBT) and propidium iodide (PÏ) staining, respectively. In senescent rats, cardiac and renal IMPPA uptake showed a significant (50%) reduction compared with young adult rats and the uptake was not significantly changed in the liver, spleen, lungs, and skeletal muscle. Total ventricular NBT staining and IMPPA uptake were almost homogeneous in young adult rats, whereas they were very heterogeneous in aged rats. In the latter, approximately 11% of the total ventricular volume showed a significantly decreased (by 60% or more) IMPPA uptake compared with normal values, and this reduction was greater in ventricle base than in apex. The myocardial areas unlabelled or poorly labelled by IMPPA represented 4, 5, 6, and 21% of the right ventricular, left ventricular epicardial, septal, and left ventricular endocardial volume, respectively, and were poorly stained with NBT. In some of these areas, PI staining indicated the presence of living cells unable to pick up NBT staining. In conclusion, in young adult rats, no myocardial lesions were observed using three different labelling techniques. However, important and significant myocardial lesioned areas were detected in senescent rats and were located preferentially in the left ventricular endocardium, as shown by a decrease in NBT staining and IMPPA uptake. These likely corresponded to a reduced number of cardiomyocytes and (or) a reduced aerobic substrate utilization, along with the development of fibrosis.Key words: senescent female rats, fatty acid analogue uptake, myocyte loss, lesioned and borderline areas.

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3386-3393 ◽  
Author(s):  
Rachel L. Leon ◽  
Xinlan Li ◽  
Jason D. Huber ◽  
Charles L. Rosen

Although estrogens are neuroprotective in young adult animal models of stroke, clinical trials demonstrate that estrogens increase the incidence and severity of stroke in aged women. We have previously shown that experimental stroke pathophysiology differs between young adult and aged rats. The aim of this study was to determine the effects of 17β-estradiol after middle cerebral artery occlusion and reperfusion in young adult and aged female rats. Focal embolic stroke was performed by middle cerebral artery occlusion with fibrin clot followed by reperfusion with iv human recombinant tissue plasminogen activator. Histological and functional outcomes were measured at 24 h after middle cerebral artery occlusion with fibrin clot. Aged rats treated with 17β-estradiol had significantly increased infarct volumes compared with placebo-treated aged rats. Young adult rats treated with 17β-estradiol had significantly decreased infarct volumes and improved functional outcome compared with ovariectomized young adult rats. Our results suggest that 17β-estradiol may act in an age-dependent manner in the postischemic rat brain. In young adult rats, it is neuroprotective; chronic treatment with 17β-estradiol during aging leads to worsened ischemic brain injury in aged female rats.


Author(s):  
Trina Sengupta ◽  
Sutirtha Ghosh ◽  
Archana Gaur T. ◽  
Prasunpriya Nayak

Background: Puberty is a developmental transition in which an estrogenic surge occurs, mediating the release of xenoestrogens, like aluminium. Aluminium’s effect on anxiety in rodents at the different developmental stages is inconsistent. Aims: This study aimed at investigating the effect of the metalloestrogenic property of aluminium on anxiety-like behavioral changes in prepubertal and young adult female rats. Objective: Considering this aim, our objective was to evaluate the anxiety-like behavior by the elevated plus maze in prepubertal and young adult female rats with or without acute exposure to aluminium. Methods: To address this property of aluminium, 5mg/Kg body weight (Al-5) and 10 mg/Kg body weight (Al-10) of aluminium was administered intraperitoneally to female rats at two developmental stages, prepubertal (PP; n = 8 for each dose) and young adult (YA; n = 6 for each dose) for two weeks. Post-treatment, three days behavioral assessment of the rats was done employing elevated plus maze. Results: Reduced escape latency was seen in Al-5, Al-10 pre-pubertal rats, and Al-5 young-adult rats on day 3. A significant reduction in open arm time was seen in the Al-5 young-adult rats. Aluminium treatment in the pre-pubertal rats reduced their head dipping and grooming. Reduced sniffing, head dipping, and stretch-attended posture in the treated young-adult female rats showed that they had impaired risk-taking tendency. Conclusion: Differential effect on the anxiety-like behavior in the pre-pubertal and young-adult female rats might be due to the metalloestrogenic property of aluminium, acting differently on the two age groups.


1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Sara I Liin ◽  
Johan E Larsson ◽  
Rene Barro-Soria ◽  
Bo Hjorth Bentzen ◽  
H Peter Larsson

About 300 loss-of-function mutations in the IKs channel have been identified in patients with Long QT syndrome and cardiac arrhythmia. How specific mutations cause arrhythmia is largely unknown and there are no approved IKs channel activators for treatment of these arrhythmias. We find that several Long QT syndrome-associated IKs channel mutations shift channel voltage dependence and accelerate channel closing. Voltage-clamp fluorometry experiments and kinetic modeling suggest that similar mutation-induced alterations in IKs channel currents may be caused by different molecular mechanisms. Finally, we find that the fatty acid analogue N-arachidonoyl taurine restores channel gating of many different mutant channels, even though the mutations are in different domains of the IKs channel and affect the channel by different molecular mechanisms. N-arachidonoyl taurine is therefore an interesting prototype compound that may inspire development of future IKs channel activators to treat Long QT syndrome caused by diverse IKs channel mutations.


2019 ◽  
Vol 27 (18) ◽  
pp. 4059-4068 ◽  
Author(s):  
Henriette Arnesen ◽  
Nadia Nabil Haj-Yasein ◽  
Jørn E. Tungen ◽  
Helen Soedling ◽  
Jason Matthews ◽  
...  

2005 ◽  
Vol 289 (1) ◽  
pp. H344-H349 ◽  
Author(s):  
Paul Gregorevic ◽  
James G. Ryall ◽  
David R. Plant ◽  
Martin N. Sillence ◽  
Gordon S. Lynch

Although β-adrenoceptor agonists have clinical merit for attenuating the age-related loss of skeletal muscle mass and strength (sarcopenia), potential cardiac-related side effects may limit their clinical application. The aim of this study was to determine whether chronic β-agonist administration impairs cardiac function in adult or aged rats. Adult (16 mo) and aged (28 mo) Fischer 344 rats were treated with fenoterol (1.4 mg·kg−1·day−1 ip) or vehicle for 4 wk. Heart function was assessed in vitro before analyses of cardiac structure and β-adrenoceptor density. Heart mass increased 17% and 25% in fenoterol-treated adult and aged rats, respectively. The increased heart mass in aged, but not adult, rats was associated with a relative increase in collagen content. Cardiac hypertrophy in adult rats was associated with an increase in left ventricular developed pressure, a marked reduction in cardiac output, and a reduction in coronary flow per unit heart mass. In contrast, negligible differences in ventricular function were observed in fenoterol-treated aged rats. The differential effect on contractile function was not associated with age-related differences in β-adrenoceptor density but, rather, an age-related increase in downregulation after treatment. Our results show that chronic β-agonist treatment impairs cardiac function to a greater extent in adult than in aged rats. These results provide important information regarding the potential effects of chronic β-agonist use on cardiac function and the future development of safe and effective treatments for sarcopenia.


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