Sexual dimorphism in age-related changes in the expression of genes involved into regulation of calcium metabolism in aorta and myocardium of rats

Age is the main risk factor for cardiovascular disease development. Understanding of mechanism underlying the vascular and myocardial ageing is necessary both for prevention and for treatment of age-associated diseases. The research aimed to evaluate age-related changes in the transcriptional activity of genes involved in the regulation of Ca2 + signalling – IP3R, RyR, and modulators of their activity CaM and Epac in blood vessels and myocardium of rats of both sexes.Gene expression was evaluated according to the mRNA content of the test protein relative to the β-actin mRNA content. It is proven that rats of both sexes develop unidirectional changes in the expression of genes encoding IP3Rs and RyR2, and different ones in the expression of protein genes modulating their activity – CaM and Epac depending on the sex of animals. In the vessels of old rats (24 months) of both sexes the relative level of mRNA for IP3R type 2 and 3 was reduced and not changed for IP3R1, and signicantly increased for RyR2 receptors compared to these indicators in young rats (4 months). In the aorta of old females the relative mRNA content for CaM and Epac1 was reduced and not changed for Epac2. On the contrary, the expression of Epac1 and Epac2 was increased by 67% and 50% respectively compared to similar indicators in young rats (4 months) and rests unchanged for CaM which indicates gender differences in the violation of subtle mechanisms for modulating the activity of RyR2 and IP3Rs in blood vessels. Old rats showed signicant changes in myocardium. In older males, the expression of RyR2,IP3R1,2, 3 increases in the left ventricle, RyR2 and IP3R1 – in the left atrium, and RyR2 and IP3R3 – in the right atrium. Unlike males, the mRNA content for RyR2, IP3R1, 2, 3 was signicantly lower in the left ventricle of females than in young animals. High levels of IP3R1 and IP3R3 expression were detected in the right atrium of senior females, and IP3R3 expression was detected in the left atrium. The expression of IP3R2 was unchanged in all parts of the female heart. In the myocardium of old rats of both sexes the expression of CaM and Epac2 proteins increased signicantly. The revealed age differences in the transcriptional activity of genes involved in the regulation of intracellular Ca2 + signalling at the level of IP3Rs-and RyR2-mediated mechanisms suggest that with the increasing life expectancy males are signicantly more likely to develop myocardial hypertrophy and heart rhythm disorders than females. Statistics. Preliminary processing of the results was performed using software incorporated into the device. Further processing was performed in Microsoft Excel using the 2–ΔΔCt algorithm. The statistical signicance of discrepancies was determined using the Student's t-test. The discrepancies were considered signicant at p < 0.05.


Introduction
Every year the world's elderly population keeps growing. As the life expectancy increases, so does the leading cause of risk worldwide that is the risk of cardiovascular diseases developing [1,2]. With age, the structural and electromechanical properties of smooth muscle cells and cardiomyocytes change in the blood vessels and heart. The precursors or manifestations of such transformations are changes in the expression levels of genes of proteins involved in the regulation of intracellular signaling and functional activity of cells [3][4][5][6][7]. Knowing the extent to which age-related changes contribute to the adaptation or development of cardiovascular diseases is extremely important. It is shown that in the process of physiological aging, the integrity of the myocardial structure is more preserved in the female body, which may be one of the reasons for the difference in life expectancy between women and men [8]. In elderly people the frequency and severity of atrial brillation increases, which plays a critical role in the genesis of sudden cardiac death. According to the results of an epidemiological study, the occurrence of atrial brillation (AF) in elderly men is higher than in women [7,[9][10][11]. It is considered that it is associated with earlier damage to the coronary arteries in men. Women are diagnosed with AF at an older age than men but they have a high risk of developing AF-related complications. Experiments on rats also demonstrated that age-related structural and functional changes in blood vessels and myocardium in males develop earlier than in females [12]. It is supposed that it is associated with a de ciency of testosterone, which can cause arrhythmogenic leakage of Ca 2+ ions from the sarcoplasmic reticulum (SR) [13].
Maintaining intracellular calcium homeostasis is crucial for normal cell function, since Ca 2+ plays central role in regulating the processes of cell excitation, contraction, transcription, and proliferation. The most important role in the generation, distribution and regulation of intracellular calcium signals is played by Ca 2+ -selective intracellular channels -inositol-1,4,5-trisphosphate (IP 3 R) and ryanodine (RyR) receptors embedded in the sarco/endoplasmic reticulum (SR/ER) membrane.
Three isoforms of the IP 3 Rs (IP3R1,2,3) and RyRs (RyR1,2,3) receptors were identi ed [20][21][22]. There is regional heterogeneity in the expression of IP 3 Rs and RyRs isoforms in blood vessels and myocardium, which seems to be important in the implementation of various physiological functions, such as excitability, contractility, and gene expression [18,[23][24][25]. Localization of these receptors on the SR/ER membrane is also isoform and is tissue-speci c [14,26].
It was shown that the most highly expressed isoform in vascular smooth muscle cells (SMCs) is IP 3 R. It is then followed with signi cant heterogeneity in expression by IP 3 R3 and IP3R2, in cardiomyocytes -by RyR2. The activity of IP 3 Rs and RyRs is stimulated by many endogenous molecules that act through G-protein coupled receptors (GPCR) and is modulated by Ca 2+ , calmodulin (CaM), protein kinases A and G (PKA and PKG), active oxygen forms, and others [27][28][29][30][31][32]. Agonists acting through the Gs-protein activate adenylate cyclase leading to an increase in the concentration of cyclic adenosine monophosphate (cAMP), activation of PKA and cAMP-binding Epac proteins (Exchange Proteins Directly Activated by cAMP), subsequent phosphorylation of IP 3 Rs and RyRs, and changes in their functional activity [16,33]. In order to understand the mechanisms underlying biological aging and to identify possible risk factors for the development of agerelated cardiovascular diseases the study featured changes in the transcriptional activity of IP 3 Rs, RyRs genes and modulators of their activity -the signal proteins CaM and Epac in the blood vessels and myocardium of rats depending on the sex of animals.
The aim of the study was to evaluate age-related changes in the transcriptional activity of protein genes involved in the regulation of Ca 2+ signaling -IP 3 Rs, RyRs receptors and modulators of their CaM and Epac activity in the blood vessels and myocardium of rats of both sexes.

Materials And Methods
The work was performed on mongrel male and female rats at the age of 4 months and 24 months. Animal welfare The rats included in the study were randomized into 4 groups: Group 1 -males aged 4 months (young, n = 10); group 2 males at the age of 24 months (old, n = 8); group 3 -females at the age of 4 months (young, n = 14); group 4-females aged 24 months (old, n = 10). Anesthetized rats (25% urethane solution, 4 ml/kg) were decapitated, the chest was opened, fragments of the heart and aorta were extracted, blood was washed off in a saline solution of sodium chloride at 4°C, after which the tissues were placed in a solution of RNAlater (Ambion, USA) and stored until RNA was isolated at -20°C. Pieces of tissue from the atria, left ventricle, and aorta were ground in liquid nitrogen. RNA extraction from tissues was performed using a GeneJET ™ kit (Thermo Fisher Scienti c Inc., USA) according to the manufacturer's protocol. The concentration of total RNA in the samples was determined using a NanoDrop ® ND-1000 spectrophotometer (Thermo Fisher Scienti c Inc., USA). The isolated total RNA was treated with DNase I (Thermo Fisher Scienti c Inc., USA) to prevent genomic DNA contamination. cDNA synthesis was performed using the RevertAidTM H Minus rst Strand cDNA Synthesis Kit (Thermo Fisher Scienti c Inc., USA) according to the manufacturer's protocol. The β-actin gene was used as a reference gene. The level of expression of the β-actin gene between the compared groups (females 4 and 24 months; males 4 and 24 months) remained unchanged in our experiments. Changes in the expression level of the target gene were assessed by changes in the mRNA level of the studied β-actin gene/mRNA. Negative controls were set according to generally accepted standards for negative controls during quantitative PCR: to exclude contamination of reagents, the reaction was started without cDNA fragments; to exclude cDNA contamination of genomic DNA, the reaction was started with a total RNA sample.
Statistics. Preliminary processing of the results was performed using software incorporated into the device. Further processing was performed in Microsoft Excel using the 2-ΔΔCt algorithm. The statistical signi cance of discrepancies was determined using the Student's t-test. The discrepancies were considered signi cant at p < 0.05.

Results And Discussion
Aorta. The level of mRNA of ryanodine (RyR2) and Inositol-1,4,5-trisphosphate (IP 3 R1, IP 3 R2, IP 3 R3) receptors as well as regulatory proteins -CaM, Epac1 and Epac2 -were evaluated in the aortic tissues of male and female rats. Analysis of the results shows that the aorta of old rats of both sexes (24 months) decreases the level of mRNA for IP 3 R2 (up to 63% and 61%, respectively in females and males) and IP 3 R3 (up to 62% and 67%, respectively in females and males) and doesn't change the expression of IP 3 R2-type receptors in comparison with similar data in young rats (4 months). It was found that in old rats regardless of the sex of animals the content of mRNA for RyR2 in blood vessels increased by more than 1,5 times (up to 153% in males and up to 185% in females) (Fig. 1a).
However, there are signi cant sexual discrepancies in nature of age-related changes in the expression of CaM genes and Epac proteins. It was proven that in old females the level of mRNA in the aorta decreases for CaM and Epac1 (by 30% and 32%, respectively) and doesn't change for Epac2 in comparison with similar indicators in the vessels of young females ( Fig.1b). In contrast to females, the expression of Epac1 and Epac2 proteins increases in the vessels of old male rats and doesn't change for CaM (Fig. 1b).

IP 3 Rs function in vessels.
IP 3 Rs play a central role in generating and maintaining myogenic vascular tone. However, it is still unknown exactly what contribution each of the three IP 3 Rs subtypes makes to the complex transmission of Ca 2+ signals in the cell. The role of IP 3 R vessels in the development of hypertension remains unclear and data available rests contradictory. It is supposed that in hypertension increased sensitivity to phenylephrine is caused by an increase in the expression of IP 3 R1 in vascular SMCs as a result of Ca 2+ -dependent activation of the transcription factor CN-NFAT (calcineurin-Nuclear factor of activated T-cells) [34]. At the same time, activation of IP 3 R1 in cerebral arteries located in close proximity to Ca 2+ -activated high-conductivity potassium channels (BKCa) has been shown to increase the sensitivity of these channels to Ca 2+ . According to the authors, this mechanism can limit IP 3 -induced vasoconstriction in the cerebral arteries [35].
Experiments on HeLa cell culture that express comparable amounts of IP 3 R1 and IP 3 R3 showed that suppression of IP 3 R1 subtype expression by RNA interference leads to a signi cant decrease in total Ca 2+ signals and the termination of Ca 2+ oscillations [17]. In contrast, suppression of IP 3 R3 expression leads to more stable and prolonged uctuations in intracellular Ca 2+ concentration than in the control. Similar effects of IP 3 R3 knockout were obtained on COS-7 cells, which primarily Express IP 3 R3 [17]. These results allowed the authors to suggest that IP 3 R1 and IP 3 R3 cells have opposite effects on the generation of intracellular Ca 2+ oscillations.
Experiments on rat aortic SMCs culture showed that proliferating cells express mainly IP 3 R2 and IP 3 R3 but during their development the expression of these types of receptors decreases, and IP 3 R1, on the contrary, increases [36,37]. It was shown that IP 3 R1 is distributed throughout the cytoplasm, IP 3 R2 is closely related to the nucleus and to the plasma membrane, and IP 3 R3 is distributed mainly around the nucleus. It is shown that each isoform of IP 3 Rs can lead to activation of apoptosis [38]. However, the IP 3 R3 isoform plays a special role in inducing apoptosis primarily by transmitting Ca 2+ signals to mitochondria, since IP 3 R3 has a special tendency to form subcellular clusters with mitochondria, which leads to the formation of associated signaling microdomains. Interestingly, IP 3 R3 can not only activate, but also inhibit apoptosis, and this process is implemented by an Akt-IP 3 R3-dependent mechanism [39].
We determined that one of the manifestations of age-related vascular changes is an imbalance in the expression of IP 3 Rs: the expression of type 2 and 3 receptors decreases and IP3R1 doesn't change. These changes in the expression of IP 3 Rs subtypes in aging vessels of animals of both sexes, apparently, can be critical for various forms of Ca 2+ signal transmission in both SMCs and endothelial cells and affect the contractile properties of vessels. In addition, it can be assumed that a signi cant decrease in the expression of IP 3 R2 and IP 3 R3 types in the aorta of old rats of both sexes is a manifestation of an age-related decrease in the proliferative and apoptotic activity of SMCs.
RyRs function in vessels.
RyRs function in SMC is less clear. Although RyRs in smooth muscles generate local Ca 2+ sparks that are similar to those observed in striated muscles, however, the contribution of these changes to the depolarization-induced global increase in intracellular Ca 2+ ([Ca 2+ ]i) concentration is quite limited. Unlike cardiac or skeletal muscles, RyR-dependent Ca 2+ -induced calcium release (CICR) isn't necessary for vasoconstriction as the concentration of Ca 2+ in vascular SMC causes vascular contraction that is lower than required for RyR-mediated CICR activation [40]. In vascular SMC RyR-mediated Ca 2+ sparks are accompanied by activation of BKCa that leads to a decrease in myogenic tone and vasodilation. At the same time, it is shown that BKCa and RyR channels play different roles in the regulation of myogenic and neurogenic tone: while BKCa and RyR channels work together to counteract myogenic vasoconstriction, BKCa channels counteract neurogenic vasoconstriction, and RyR channels, on the contrary, enhance it [41]. The authors suggest that at the level of neurogenic vasoconstriction of resistive arteries, RyRs act in conjunction with voltage-dependent L-type Ca 2+ channels.
It was determined that in vessels of old females and males, the level of mRNA RyR2 increases by 1. For RyRs calcium is the main physiological activity regulator [30,42]. With a moderate increase in [Ca 2+ ] i the excitation of RyRs is mediated through activation of CaMK-dependent channel phosphorylation or by interaction of Ca 2+ with the Ca 2+ -binding protein S100A which competes with СaM for binding to RyRs. Vasodilators that act on receptors associated with the Gs protein activate adenylate cyclase, which leads to an increase in cAMP and subsequent activation of PKA-and Epacmediated phosphorylation of RyRs, which leads to an increase in the frequency of RyR-dependent local calcium signals, followed by activation of BKCa-channels and vasodilation. At a high level of [Ca 2+ ] i, RyR activity, in contrast, is inhibited through mechanisms including Ca 2+ -binding sorbin proteins (SORC) or CaM [16].
Thus, considering aging, unidirectional changes in the expression of genes for channel proteins IP 3 Rs and RyR2 develop in the aorta of rats, and changes in the expression of proteins that modulate their activity -CaM and Epac indicating agerelated changes in intracellular calcium metabolism. It can be assumed that a high level of Epac1 and Epac 2 expression in the vessels of old male rats negatively affects the activity of IP3Rs and positively affects RyRs, since Epac-induced phosphorylation leads to a decrease in the activity of the former and an increase in the latter. A decrease in CaM expression in the vessels of older females may lead to a decrease in its inhibitory effect on IP 3 Rs and RyRs, and Epac1 may lead to a decrease in its activating effect on RyR2 and inhibiting on IP 3 Rs. Apparently, one of the aging vessels signs is a violation of the goodness of t modulation mechanisms of the most important ion channels involved in the regulation of [Ca 2+ ]i, which have a certain speci city in female and male rats. The detected changes can make a signi cant contribution to age-initiated vascular pathology at the level of their contractile, proliferative and apoptotic activity. However, it is possible that some of them may be a manifestation of compensatory mechanisms aimed at preserving Ca 2+ -homeostasis in aging vessels.
Heart. It was determined that in old male rats, the level of mRNA RyR2 increases in the left ventricle and both atria (Fig. 2). In older males, the content of mRNA in the left ventricle increases for all three types of IP 3 Rs, in the left atrium only for IP 3 R1type, in the right atrium -increases for IP 3 R3-type, but the level of mRNA for IP 3 R2-type decreases compared to control animals (Fig. 2).
Other age-related changes in the expression of the RyR2 and IP 3 Rs genes were detected in the hearts of old females. It was found that the expression of RyR2, IP 3 R1, and IP3R3 decreases in the left ventricle during aging in females in contrast to males, while the level of mRNA for IP 3 R3-type increases in the left atrium, and for IP 3 R1 -and IP 3 R3 -type receptors in the right atrium (Fig. 2). the level of expression of IP 3 R2-type mRNA in the hearts of old females does not differ from the indicators in the hearts of young rats.
While aging, the expression of CaM and Epac2 increases signi cantly in the left ventricle and atria of rats of both sexes as evidenced by a higher level of their mRNA compared to similar indicators in young animals (Fig. 3). In older males, the mRNA level for Epac1 remains unchanged in the heart, while in females, the mRNA level of this protein decreases in the left ventricle and, on the contrary, increases in the left atrium (Fig. 3).
It is known that the aging heart is characterized by a reduced response to sympathetic stimulation, a high risk of arrhythmias and sudden cardiac death [43][44][45]. Age-related electrical instability and contractile dysfunction of the myocardium are primarily associated with impaired Ca 2+homeostasis. However, speci c molecular mechanisms underlying the altered regulation of Ca2+ metabolism in the aging heart remain poorly understood. It is shown that older people have reduced functional activity of the sinoatrial node, that is believed to be associated with an age-related decrease in the expression of the main Ca 2+ -conducting channel SR-RyR2, as well as with changes in the expression of other ion channels -an increase in Na(v)1.5, Na(v)β1 and Ca(v)1.2 and a decrease in K(v)1.5 and HCN1 [46].

RyRs function in heart.
It is supposed that RyR2 receptors are the key intracellular structures that implement the effect of the sympathetic nervous system on the myocardium. Our research has shown that in older males, the expression of RyR2 increases signi cantly in the left ventricle and atria, while in females, on the contrary, it decreases in the left ventricle and doesn't change in the atria.
Along with a change in the expression of RyR2 in the aging hearts of rats of both sexes, a high level of expression of the mRNA proteins CaM and Epac2 was detected. Changes in the transcription level of these genes can lead to excessive activation of RyR2 and to serious violations of calcium metabolism in cardiomyocytes [25,47]. It was found that an excessive increase in the activity of RyR2 as a result of their oxidation, nitrosylation or hyperphosphorylation contributes to the development of heart failure and the occurrence of ventricular arrhythmias [48,49]. It is known that activation of βadrenoreceptors (β-AR) can trigger cardiac arrhythmias through cAMP-dependent mechanisms by increasing Ca 2+ leakage from SR to diastole. cAMP can activate both PKA and Epac proteins. In studies using genetic modi cations of Epac1, Epac2, RyR2, and CaMKII, it has been shown that activation of Epac and PKA can equally contribute to the occurrence of β-ARinduced arrhythmias and Ca 2+ leak from SR. It has been proved that the β1-AR induced increase in arrhythmogenic Ca 2+ emissions is mediated by Epac2 [50]. The arrhythmogenic effect of Epac2 has been demonstrated in numerous studies in recent years [47,51]. It was found that the β-AR-cAMP-Epac2-PI3K-Akt-NOS1-CaMKII signaling cascade mediates increased (pathological) Ca 2+ leak from SR to diastole, while the cAMP-PKA pathway mainly implements inotropic and lucitropic effects of β-AR [52].
In cardiomyocytes, CaM regulates the activity of RyR2 by direct interaction with them, as well as through CaMKII, which phosphorylate both RyR2 and IP 3 Rs [53].  [55,56]. Our data on the high level of expression of RyR2, СaM and Epac2 in the hearts of old animals suggest that males are much more likely to develop myocardial hypertrophy and ventricular arrhythmias than females (Fig. 2, 3).

IP 3 Rs heart functions.
If the role of RyR2 as a receptor regulating the release of Ca 2+ from SR, necessary for the implementation of electromechanical coupling of cardiomyocytes is obvious, there is still no clear understanding of IP 3 Rs contribution to this process. Under physiological conditions cardiomyocytes, in contrast to non-excitable cells, have a low level of Gq-induced IP3 generation and a weak IP 3 R response [18]. The role of IP 3 Rs in pathophysiology, especially in arrhythmogenesis and myocardial hypertrophy, is more obvious. Currently, it is proved that in the global increase in [Ca 2+ ]i in cardiomyocytes, the share of IP 3 R-induced release of Ca 2+ from SR is insigni cant, which makes their contribution to the regulation of the process of electro-mechanical coupling of cardiomyocytes minimal. It is considered that an important condition for IP 3 Rs activation is their localization in the subsarcolemmal zone meaning in the immediate vicinity of the IP 3 generation site [18].
This study identi es sexual dimorphisms of age-related changes in the expression level of IP 3 R1-IP 3 R3 type receptors in the left ventricle of the hearts of old rats. Thus, in old males, the expression of IP 3 R1, IP 3 R2, and IP 3 R3 in the left ventricle was signi cantly higher, while in females, on the contrary, it was lower (IP 3 R1 and IP 3 R3) than in the hearts of young rats. IP 3 R1 is localized in the heart mainly in conducting and IP 3 R2 in contractile cardiomyocytes and IP 3 R2 is located mainly in the perinuclear membrane region in ventricular cardiomyocytes [57,58]. Atrial cells express a greater number of IP 3 Rs compared to ventricular cardiomyocytes. They are mostly dominated by type 1 and type 2 IP 3 Rs [59]. In atria the amount of IP 3 R2 is 6-10 times greater than in ventricles, and in SR they are in close proximity to the sarcolemma in close proximity to the RyRs [57,58]. It has been shown that agonist-induced activation of phospholipase C (PLC) in atrial cardiomyocytes causes local Ca 2+ sparks that can be transmitted to nearby RyR2 and amplify the CICR response, and thus IP 3 Rs can affect the process of electro-mechanical coupling in atria [60]. It is assumed that IP 3 R-induced activation of RyR2, other ion channels and exchangers, in particular Ca 2+ -l-type channels and Na+/Ca 2+ -exchanger, can lead to atrial brillation [59].
Taking into account the literature data on the predominant localization of IP 3 R1 type in conducting cardiomyocytes, it can be assumed that an increase in the expression of this receptor isoform in the left ventricle and left atrium of old male rats is a risk factor for arrhythmias. In addition, a high level of IP 3 R2 expression in the left atrium can also provoke atrial brillation, since their role in arrhythmogenesis has been proven [61,62].
It was determined that the GPCR/IP 3 R axis modulates not only heart rhythm disorders but also the hypertrophy development. There is strong evidence that IP 3 R2 is involved in the development of myocardial hypertrophy under conditions of increased expression of these receptors and/or their over-activation as a result of agonist-induced signaling from GPCR [63], and these mechanisms are implemented at the level of nuclear membranes.
In recent years, more and more attention has been paid to studying the features of Ca 2+ signal transmission in the nuclei of cardiomyocytes and their role in the regulation of gene transcription [64,65]. The transcription of genes and cell growth is in uenced by nuclear Ca 2+ signals, which differ from cytosolic Ca 2+ signals. HDACs, which leads to the activation of MEF2-dependent transcription of various genes (myocyte enhancer factor-2) [70].
The CaN-NFAT transcriptional pathway is also activated. The presence of local Ca 2+ -dependent mechanisms of IP 3 R2mediated regulation of nuclear pore permeability for transcription factor tra c in adult rat cardiomyocytes suggests that IP 3 R2 is involved in the development of pathological left ventricular hypertrophy in old males. This assumption is supported by the high level of expression of IP 3 R2, as well as CaM in cardiomyocytes of the left ventricle of rats at the age of 24 months compared with similar rates in young rats.
In contrast to males, older females are highly likely to develop atrial brillation, since the level of IP 3 R1 expression signi cantly increases in the right atrium of females during aging. An increase in IP3Rs is also observed in atrial cardiomyocytes in patients with chronic atrial brillation [71,72]. Unlike males, in older females, the risk of developing ventricular arrhythmias, as well as their hypertrophy, is minimal, since they have a low level of expression of RyR2, IP 3 R1 and IP 3 R3 in the left ventricle and unchanged for IP 3 R2 type.
It has been determined that the IP 3 R3 receptor isoform is involved in the development of various human diseases [73].
However, the role of IP 3 R3 in the regulation of cardiac activity in normal and pathological conditions has been less studied. It is known that IP 3 R3-dependent Ca 2+signaling is necessary for NO-induced differentiation of cardiomyocytes obtained from embryonic stem cells [74]. Based on the above data on the important contribution of IP 3 R3 to the modulation of the generation of Ca 2+ oscillations [17], it can be assumed that a signi cant increase in the expression of these receptors in cardiomyocytes of rats of both sexes in combination with altered expression of RyR2, IP3R1 and IP 3 R2 indicates a transition to a new level of regulation of intracellular calcium exchange in the hearts of old rats.

Conclusions
Aging is a natural process of withering of the functional activity of the body at the level of all systems and organs which leads to reprogramming of the gene expression pro le primarily aimed at maintaining vital activity in the conditions of changing needs of the body, i.e. they are adaptive. The most important role in these processes is played by cytosolic and nuclear Ca 2+ signaling. Along with it, taking into consideration the data obtained, there is every reason to believe that in the process of aging of the body, signi cant changes occur in the SMCs and cardiomyocytes at the level of regulation of intracellular calcium metabolism that can make a signi cant contribution to the development of age-associated cardiovascular diseases. The revealed sexual-age dimorphisms in the transcriptional activity of genes involved in the regulation of intracellular Ca 2+ signaling at the level of IP 3 Rs -and RyR2-mediated mechanisms suggest that with increasing life expectancy, males are signi cantly more likely to develop myocardial hypertrophy and heart rhythm disorders than females. Age-related changes in the expression level of RyR2 and IP 3 Rs genes and modulators of their activity -CaM and Epac in the aorta can also negatively affect vascular contractility in old age.

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