Apelin and Visfatin Plasma Levels in Healthy Individuals With High Normal Blood Pressure

LncRNA NEAT1 aggravates human microvascular endothelial cell injury by inhibiting the Apelin/Nrf2/HO-1 signalling pathway in type 2 diabetes mellitus with obstructive sleep apnoea

Long noncoding RNAs (lncRNAs) regulate the progression of type 2 diabetes mellitus complicated with obstructive sleep apnoea (T2DM-OSA). However, the role of the lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) in T2DM-OSA remains unknown. This study aimed to reveal the function of NEAT1 in T2DM-OSA and the underlying mechanism. KKAy mice were exposed to intermittent hypoxia (IH) or intermittent normoxia to generate a T2DM-OSA mouse model. HMEC-1 cells were treated with high glucose (HG) and IH to construct a T2DM-OSA cell model. RNA expression was detected by qRT-PCR. The protein expression of Apelin, NF-E2-related factor 2 (Nrf2), haem oxygenase-1 (HO-1), and up-frameshift suppressor 1 (UPF1) was assessed using western blot. Cell injury was evaluated using flow cytometry, enzyme-linked immunosorbent assay, and oxidative stress kit assays. RIP, RNA pull-down, and actinomycin D assays were performed to determine the associations between NEAT1, UPF1, and Apelin. NEAT1 expression was upregulated in the aortic vascular tissues of mice with T2DM exposed to IH and HMEC-1 cells stimulated with HG and IH, whereas Apelin expression was downregulated. The absence of NEAT1 protected HMEC-1 cells from HG- and IH-induced damage. Furthermore, NEAT1 destabilized Apelin mRNA by recruiting UPF1. Apelin overexpression decreased HG- and IH-induced injury to HMEC-1 cells by activating the Nrf2/HO-1 pathway. Moreover, NEAT1 knockdown reduced HG- and IH-induced injury to HMEC-1 cells through Apelin. NEAT1 silencing reduced HMEC-1 cell injury through the Apelin/Nrf2/HO-1 signalling pathway in T2DM-OSA.Abbreviations: LncRNAs, long non-coding RNAs; T2DM, type 2 diabetes mellitus; OSA, obstructive sleep apnoea; NEAT1, nuclear paraspeckle assembly transcript 1; IH, intermittent hypoxia; HMEC-1, human microvascular endothelial cells; HG, high glucose; Nrf2, NF-E2-related factor 2; UPF1, up-frameshift suppressor 1; HO-1, haem oxygenase-1; qRT-PCR, quantitative real-time polymerase chain reaction; ELISA, enzyme-linked immunosorbent assay; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; TNF-α, tumour necrosis factor-α; CCK-8, Cell Counting Kit-8; IL-1β, interleukin-1β; ROS, reactive oxygen species; MDA, malondialdehyde; SOD, superoxide dismutase; RIP, RNA immunoprecipitation; SD, standard deviations; GSH, glutathione; AIS, acute ischaemic stroke; HMGB1, high mobility group box-1 protein; TLR4, toll-like receptor 4.

Role of major adipokines in hypertension: A literature review

The incidence and prevalence of hypertension are increasing as a consequence of the obesity epidemic. Adipocytes and their variety of factors make contributions to the long-term regulation of blood pressure. The pathophysiologic states of hypertension, including obesity, are regulated by the production of adipocyte-derived factors. Increased body mass index was closely linked to elevated blood pressure. Mostly the hypertensive subjects were obese as well as overweight. There are numerous adipokines, however, this review article only focuses on the major adipokines including chemerin, visfatin, retinol-binding protein 4, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, omentin-1, lipocalin-2, vaspin, progranulin, complement c1q tumor necrosis factor-related protein, and nesfatin-1 role in the pathogenesis of hypertension. This review article concludes the significant association of major adipokines in the pathogenesis of hypertensives. New research should be focused on other newly reported adipokine roles in hypertensive subjects and the management of these adipokines in hypertensive subjects. The discovery of this information could result in the creation of antihypertensive medications, particularly those that focus on obesity-related hypertension.

Chronic Resistance Training Effects on Serum Adipokines in Type 2 Diabetes Mellitus: A Systematic Review

(1) Background: Non-communicable diseases (NCD) are an important concern for public health because of their high rates of morbidity and mortality. A prevalent lifestyle-linked NCD is type 2 diabetes mellitus (T2D). Recently, molecular biomarkers secreted by adipocytes, called adipokines, have been linked with T2D and muscle function disturbances. However, the effects of resistance training (RT) interventions on adipokine levels in patients with T2D have not been systematically studied. (2) Methods: The PRISMA guidelines were followed. Searches for the studies were performed in the PubMed/MEDLINE and Web of Science electronic databases. Eligibility criteria included: (i) participants with T2D; (ii) RT interventions; (iii) randomized controlled trials; and (iv) measurement of serum adipokines. The PEDro scale was used to assess the methodological quality of the selected studies. Significant differences (p ≤ 0.05) and effect size were screened for each variable. (3) Results: Of the initial 2166 records, database search extraction yielded 14 studies to be included. The methodological quality of the included data was high (median PEDro score of 6.5). Analyzed adipokines in the included studies were leptin, adiponectin, visfatin, apelin, resistin, retinol-binding protein 4 (RBP4), vaspin, chemerin, and omentin. RT interventions (6-52 weeks; minimal effective duration >12 weeks) exert a meaningful effect on serum adipokine, (e.g., leptin) levels in T2D patients. (4) Conclusions: RT may be an alternative, but not an optimal, option in adipokine disruptions in T2D. Combined (i.e., aerobic and RT) long-term training may be considered the optimal intervention for treating adipokine level disturbances.

Changes in serum levels of apelin and nitric oxide in hospitalized patients with COVID-19: association with hypertension, diabetes, obesity, and severity of disease

Background

COVID-19 is an infectious disease currently spreading worldwide. The COVID-19 virus requires angiotensin-converting enzyme 2, an enzyme that plays a vital role in regulating the apelinergic system for entry into target cells. The underlying diseases of hypertension, diabetes mellitus, and obesity are risk factors for the severity of COVID-19 infection. This study aimed to compare the serum levels of apelin and nitric oxide in hospitalized COVID-19 patients and non-COVID-19 subjects with and without the mentioned risk factors.

Methods

Serum samples were taken from 69 COVID-19 patients and 71-matched non-COVID-19 participants enrolled in the Kerman coronary artery disease risk factors cohort study. Study participants were divided into eight groups of control (healthy), hypertension, diabetes mellitus, obesity, COVID-19, COVID-19 + hypertension, COVID-19 + diabetes mellitus, and COVID-19 + obesity (n = 15–20 in each group). Serum apelin and nitrite were measured by the enzyme-linked immunosorbent assay and colorimetric methods, respectively.

Results

Hypertensive and obese patients had lower serum apelin compared to the control group. In addition, apelin content was lower in the COVID-19 and COVID-19 + diabetes mellitus groups compared to the non-COVID-19 counterpart groups. Serum apelin levels were positively associated with arterial O₂sat. and negatively with the severity of lung involvement. Nitric oxide metabolites were significantly lower in the COVID-19, COVID-19 + diabetes mellitus, and COVID-19 + obesity groups.

Conclusions

The lower apelin and nitric oxide levels in patients with hypertension and obesity or their reduction due to infection with COVID-19 or concomitant COVID-19 + diabetes mellitus may make them vulnerable to experiencing severe diseases.

Adipokines as Immune Cell Modulators in Multiple Sclerosis

Multiple sclerosis (MS), a chronic inflammatory and demyelinating disease of the central nervous system (CNS), is a major clinical and societal problem, which has a tremendous impact on the life of patients and their proxies. Current immunomodulatory and anti-inflammatory therapies prove to be relatively effective; however, they fail to concomitantly stop ongoing neurological deterioration and do not reverse acquired disability. The proportion to which genetic and environmental factors contribute to the etiology of MS is still incompletely understood; however, a recent association between MS etiology and obesity was shown, with obesity greatly increasing the risk of developing MS. An altered balance of adipokines, which are white adipose tissue (WAT) hormones, plays an important role in the low-grade chronic inflammation during obesity by their pervasive modification of local and systemic inflammation. Vice versa, inflammatory factors secreted by immune cells affect adipokine function. To explore the role of adipokines in MS pathology, we will here review the reciprocal effects of adipokines and immune cells and summarize alterations in adipokine levels in MS patient cohorts. Finally, we will discuss proof-of-concept studies demonstrating the therapeutic potential of adipokines to target both neuroinflammation and neurodegeneration processes in MS.

Roles of Perivascular Adipose Tissue in Hypertension and Atherosclerosis

Significance: Perivascular adipose tissue (PVAT), which is present surrounding most blood vessels, from the aorta to the microvasculature of the dermis, is mainly composed of fat cells, fibroblasts, stem cells, mast cells, and nerve cells. Although the PVAT is objectively present, its physiological and pathological significance has long been ignored. Recent Advances: PVAT was considered as a supporting component of blood vessels and a protective cushion to the vessel wall from the neighboring tissues during relaxation and contraction. Nonetheless, further extensive research found that PVAT actively regulates blood vessel tone through PVAT-derived vasoactive factors, including both relaxing and contracting factors. In addition, PVAT contributes to atherosclerosis through paracrine secretion of a large number of bioactive factors such as adipokines and cytokines. Thereby, PVAT regulates the functions of blood vessels through various mechanisms operating directly on PVAT or on the underlying vessel layers, including vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). Critical Issues: PVAT is a unique adipose tissue that plays an essential role in maintaining the vascular structure and regulating vascular function and homeostasis. This review focuses on recent updates on the various PVAT roles in hypertension and atherosclerosis. Future Directions: Future studies should further investigate the actual contribution of alterations in PVAT metabolism to the overall systemic outcomes of cardiovascular disease, which remains largely unknown. In addition, the messengers and underlying mechanisms responsible for the crosstalk between PVAT and ECs and VSMCs in the vascular wall should be systematically addressed, as well as the contributions of PVAT aging to vascular dysfunction.

Pioglitazone protects blood vessels through inhibition of the apelin signaling pathway by promoting KLF4 expression in rat models of T2DM

Apelin, identified as the endogenous ligand of APJ, exerts various cardiovascular effects. However, the molecular mechanism underlying the regulation of apelin expression in vascular cells is poorly described. Pioglitazone (PIO) and Krüppel-like factor 4 (KLF4) exhibit specific biological functions on vascular physiology and pathophysiology by regulating differentiation- and proliferation-related genes. The present study aimed to investigate the roles of PIO and KLF4 in the transcriptional regulation of apelin in a high-fat diet/streptozotocin rat model of diabetes and in PIO-stimulated vascular smooth muscle cells (VSMCs). Immunohistochemistry, qRT-PCR, and Western blotting assays revealed that the aorta of the Type 2 diabetes mellitus (T2DM) rat models had a high expression of apelin, PIO could decrease the expression of apelin in the PIO-treated rats. In vitro, Western blotting assays and immunofluorescent staining results showed that the basal expression of apelin was decreased but that of KLF4 was increased when VSMCs were stimulated by PIO treatment. Luciferase and chromatin immunoprecipitation assay results suggested that KLF4 bound to the GKLF-binding site of the apelin promoter and negatively regulated the transcription activity of apelin in VSMCs under PIO stimulation. Furthermore, qRT-PCR and Western blotting assay results showed that the overexpression of KLF4 markedly decreased the basal expression of apelin, but the knockdown of KLF4 restored the PIO-induced expression of apelin. In conclusion, PIO inhibited the expression of apelin in T2DM rat models to prevent diabetic macroangiopathy, and negatively regulated the gene transcription of apelin by promoting transcription of KLF4 in the apelin promoter.

The interaction partners of (pro)renin receptor in the distal nephron

The (pro)renin receptor (PRR), a key regulator of intrarenal renin-angiotensin system (RAS), is predominantly presented in podocytes, proximal tubules, distal convoluted tubules, and the apical membrane of collecting duct A-type intercalated cells, and plays a crucial role in hypertension, cardiovascular disease, kidney disease, and fluid homeostasis. In addition to its well-known renin-regulatory function, increasing evidence suggests PRR can also act in a variety of intracellular signaling cascades independently of RAS in the renal medulla, including Wnt/β-catenin signaling, cyclooxygenase-2 (COX-2)/prostaglandin E₂ (PGE₂ ) signaling, and the apelinergic system, and work as a component of the vacuolar H⁺ -ATPase. PRR and these pathways regulate the expression/activity of each other that controlling blood pressure and renal functions. In this review, we highlight recent findings regarding the antagonistic interaction between PRR and ELABELA/apelin, the mutually stimulatory relationship between PRR and COX-2/PGE₂ or Wnt/β-catenin signaling in the renal medulla, and their involvement in the regulation of intrarenal RAS thereby control blood pressure, renal injury, and urine concentrating ability in health and patho-physiological conditions. We also highlight the latest progress in the involvement of PRR for the vacuolar H⁺ -ATPase activity.

Effects of hesperidin in orange juice on blood and pulse pressures in mildly hypertensive individuals: a randomized controlled trial (Citrus study)

Purpose

To assess the sustained and acute effects, as well as the influence of sustained consumption on the acute effects, of orange juice (OJ) with a natural hesperidin content and hesperidin-enriched OJ (EOJ) on blood (BP) and pulse (PP) pressures in pre- and stage-1 hypertensive individuals.

Methods

In a randomized, parallel, double-blind, placebo-controlled trial, participants (n = 159) received 500 mL/day of control drink, OJ, or EOJ for 12 weeks. Two dose–response studies were performed at baseline and after 12 weeks.

Results

A single EOJ dose (500 mL) reduced systolic BP (SBP) and PP, with greater changes after sustained treatment where a decrease in diastolic BP (DBP) also occurred (P < 0.05). SBP and PP decreased in a dose-dependent manner relative to the hesperidin content of the beverages throughout the 12 weeks (P < 0.05). OJ and EOJ decreased homocysteine levels at 12 weeks versus the control drink (P < 0.05). After 12 weeks of EOJ consumption, four genes related to hypertension (PTX3, NLRP3, NPSR1 and NAMPT) were differentially expressed in peripheral blood mononuclear cells (P < 0.05).

Conclusion

Hesperidin in OJ reduces SBP and PP after sustained consumption, and after a single dose, the chronic consumption of EOJ enhances its postprandial effect. Decreases in systemic and transcriptomic biomarkers were concomitant with BP and PP changes. EOJ could be a useful co-adjuvant tool for BP and PP management in pre- and stage-1 hypertensive individuals.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02279-0) contains supplementary material, which is available to authorized users.

The Association of Plasma Apelin Levels with Plaque Vulnerability

Objectives:

Apelin is a recently discovered peptide that is expressed in many tissues particularly in the cardiovascular system and exerts several actions, most of which are vasodilatory and positive inotropic effects. Based on this, an apelin deficiency is believed to play a significant role in the development of hypertension and heart failure. However, the association of apelin with the pathogenesis of atherosclerosis and especially plaque vulnerability remains unestablished. Thus, to contribute to the literature, in this study, we sought to determine the association of apelin concerning plaque vulnerability in the setting of the acute coronary syndrome.

Methods:

In this study, we prospectively enrolled a total of 80 patients; 40 with acute coronary syndrome and 40 patients with stable chronic ischemic heart disease. Plasma apelin levels were measured in all patients along with other routine biochemical parameters, and all patients underwent a transthoracic echocardiographic examination.

Results:

Plasma apelin levels were significantly lower in patients with the acute coronary syndrome (221.2±66.7 vs 254.3±77.9 p=0.04). However, there was no correlation between plasma apelin levels and serum inflammatory markers or coronary artery disease severity.

Conclusion:

Low plasma apelin levels may create a tendency towards vulnerable plaque and acute coronary syndrome.

Visfatin/eNampt induces endothelial dysfunction in vivo: a role for Toll-Like Receptor 4 and NLRP3 inflammasome

Visfatin/extracellular-nicotinamide-phosphoribosyltranferase-(eNampt) is a multifaceted adipokine enhanced in type-2-diabetes and obesity. Visfatin/eNampt cause in vitro endothelial dysfunction and vascular inflammation, although whether the same effects are achieved in vivo is unknown. Toll-like receptor-4 (TLR4), a main surface pattern recognition receptor of innate immune system is a potential target for visfatin/eNampt. We studied its capacity to generate vascular dysfunction in vivo, focusing on TLR4 role and downstream activation of nod-like-receptor-protein-3 (NLRP3)-inflammasome. 4 month-old C57BL/6 mice were exposed to 7 days infusion of visfatin/eNampt, alone or together with FK 866 (Nampt enzymatic inhibitor), CLI 095 (TLR4 blocker), MCC 950 (NLRP3-inflammasome inhibitor), or anakinra (interleukin(IL)-1-receptor antagonist). Endothelial dysfunction was tested in isolated microvessels. In human umbilical endothelial cells (HUVEC), proteins related to the NLRP3-inflammasome phosphorylated p-65, NLRP3, caspase-1, pro-IL-1β, and mature IL-1β were determined by Western blot, while the inflammasome related apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC-specks) was studied by immunofluorescence. Impaired endothelium-dependent relaxations were observed in isolated mesenteric microvessels from visfatin/eNampt-infused mice. This effect was attenuated by co-treatment with FK 866 or CLI 095, supporting a role for Nampt enzymatic activity and TLR4 activation. Moreover, cultured HUVEC exposed to visfatin/eNampt showed higher expression and activation of NLRP3-inflammasome. Again, this effect relied on Nampt enzymatic activity and TLR4 activation, and it was abrogated by the inflammasome assembly blockade with MCC 950. The endothelial dysfunction evoked by visfatin/eNampt infusion in vivo was also sensitive to both MCC 950 and anakinra treatments, suggesting that the NLRP3-inflammasome-driven tissular release of IL-1β is the final mediator of endothelial damage. We conclude that Visfatin/eNampt produces in vivo vascular dysfunction in mice by a Nampt-dependent TLR4-mediated pathway, involving NLRP3-inflammasome and paracrine IL-1β. Thus, those targets may become therapeutic strategies for attenuating the adipokine-mediated vascular dysfunction associated to obesity and/or type-2-diabetes.

Distinct hemodynamic responses to (pyr)apelin-13 in large animal models

This study tested the hypothesis that (pyr)apelin-13 dose-dependently augments myocardial contractility and coronary blood flow, irrespective of changes in systemic hemodynamics. Acute effects of intravenous (pyr)apelin-13 administration (10 to 1,000 nM) on blood pressure, heart rate, left ventricular pressure and volume, and coronary parameters were measured in dogs and pigs. Administration of (pyr)apelin-13 did not influence blood pressure (P = 0.59), dP/dt_max (P = 0.26), or dP/dt_min (P = 0.85) in dogs. However, heart rate dose-dependently increased > 70% (P < 0.01), which was accompanied by a significant increase in coronary blood flow (P < 0.05) and reductions in left ventricular end-diastolic volume and stroke volume (P < 0.001). In contrast, (pyr)apelin-13 did not significantly affect hemodynamics, coronary blood flow, or indexes of contractile function in pigs. Furthermore, swine studies found no effect of intracoronary (pyr)apelin-13 administration on coronary blood flow (P = 0.83) or vasorelaxation in isolated, endothelium-intact (P = 0.89) or denuded (P = 0.38) coronary artery rings. Examination of all data across (pyr)apelin-13 concentrations revealed an exponential increase in cardiac output as peripheral resistance decreased across pigs and dogs (P < 0.001; R² = 0.78). Assessment of the Frank-Starling relationship demonstrated a significant linear relationship between left ventricular end-diastolic volume and stroke volume across species (P < 0.001; R² = 0.70). Taken together, these findings demonstrate that (pyr)apelin-13 does not directly influence myocardial contractility or coronary blood flow in either dogs or pigs.NEW & NOTEWORTHY Our findings provide much needed insight regarding the pharmacological cardiac and coronary effects of (pyr)apelin-13 in larger animal preparations. In particular, data highlight distinct hemodynamic responses of apelin across species, which are independent of any direct effect on myocardial contractility or perfusion.

Superoxide anions modulate the performance of apelin in the paraventricular nucleus on sympathetic activity and blood pressure in spontaneously hypertensive rats

The present study was designed to determine how apelin in paraventricular nucleus (PVN) modulates the renal sympathetic nerve activity (RSNA), arterial blood pressure (ABP), mean arterial pressure (MAP), and heart rate (HR), and whether superoxide anions regulate the performance of PVN apelin in spontaneously hypertensive rats (SHRs). Acute experiment was carried out with 13-week-old male Wistar-Kyoto rats (WKY) and SHRs under anaesthesia. RSNA, ABP, MAP and HR after PVN microinjection were measured. Apelin microinjection into PVN increased RSNA, ABP, MAP and HR in WKY rats and SHRs, more obviously in SHRs. APJ antagonist F13A decreased the RSNA, ABP, MAP and HR in SHRs, and inhibited the effects of apelin. Apelin and APJ mRNA levels were higher in the PVN in SHRs. PVN microinjection of superoxide anion scavengers tempol and tiron, or NAD(P)H oxidase inhibitor apocynin, decreased the RSNA, ABP, MAP and HR in SHRs, and inhibited the effects of apelin, but the superoxide dismutase (SOD) inhibitor diethyldithiocarbamic acid (DETC) potentiated the effects of apelin. NAD(P)H oxidase activity and superoxide anion levels in PVN were increased by apelin, but decreased by APJ antagonist F13A. The apelin-induced increases in NAD(P)H oxidase activity and superoxide anion level were abolished by pre-treatment with F13A. These results indicate that apelin in PVN increases the sympathetic outflow and blood pressure via activating APJ receptor. The enhanced activity of endogenous apelin and APJ receptor in PVN contributes to sympathetic activation in hypertension, and the superoxide anion is involved in these apelin-mediated processes in PVN.

Effects of genistein on blood pressure: A systematic review and meta-analysis

Genistein (4',5,7-trihydroxyisoflavone) is a phytoestrogen with potential health benefits in the prevention of cardiovascular disease. However, the evidence regarding its effects on hypertension has not been conclusive. Therefore, we examined the impact of oral genistein supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP) via a systematic review and meta-analysis of randomized controlled trials (RCTs). PubMed, ISI Web of Science, Scopus and the Cochrane library databases (until August 2019) were searched to identify potential RCTs with information on genistein supplementation and hypertension. Weighted Mean Difference (WMD) was pooled using a random-effects model. Pooling four RCTs (four treatment arms) together did not show any significant reduction of SBP (WMD: -5.32 mmHg, 95% CI: -14.59 to 3.96) and DBP (WMD: -2.06 mmHg, 95% CI: -6.41 to 2.28) compared to that of the placebo group. However, subgroup analysis by intervention duration suggested that more than 6 months genistein supplementation in metabolic syndrome patients can significantly decrease SBP (WMD: -13.73 mmHg, 95% CI: -18.10 to -9.37) and DBP (WMD: -5.18 mmHg, 95% CI: -6.62 to -3.74). Generally, present study indicated that genistein supplementation had no effect on hypertension, but it seems that longer intervention duration of more than 6 months especially among metabolic syndrome patients may lead to the effectiveness of genistein.

Mechanistic Links Between Obesity, Diabetes, and Blood Pressure: Role of Perivascular Adipose Tissue

Obesity is increasingly prevalent and is associated with substantial cardiovascular risk. Adipose tissue distribution and morphology play a key role in determining the degree of adverse effects, and a key factor in the disease process appears to be the inflammatory cell population in adipose tissue. Healthy adipose tissue secretes a number of vasoactive adipokines and anti-inflammatory cytokines, and changes to this secretory profile will contribute to pathogenesis in obesity. In this review, we discuss the links between adipokine dysregulation and the development of hypertension and diabetes and explore the potential for manipulating adipose tissue morphology and its immune cell population to improve cardiovascular health in obesity.

Evaluation of elabela, apelin and nitric oxide findings in maternal blood of normal pregnant women, pregnant women with pre-eclampsia, severe pre-eclampsia and umbilical arteries and venules of newborns

Pre-eclampsia is multisystem metabolic diseases, commonly accompanied by hypertension and proteinuria, which are among the important causes of maternal and perinatal mortality and morbidity worldwide. In a pre-eclampsia animal model study in the last year, Elabela (ELA) infusion was reported to correct hypertension and proteinuria and to normalise the birth weights of the offspring. Therefore, our main goal in this human study is to compare ELA, apelin (APLN) and nitric oxide (NO) levels in the maternal blood of pregnant women with pre-eclampsia and severe pre-eclampsia and in their newborns' venous-arterial cord blood with maternal blood of healthy pregnant women and their newborns' venous-arterial cord blood. Thirty controls, 28 pre-eclampsia and 24 severe pre-eclampsia cases and their newborns participated in this study. Maternal blood and newborn venous-arterial cord blood samples were collected from these patients. ELA, APLN and NO levels in these samples were measured by ELISA method. When the maternal blood ELA, APLN and NO amounts were compared with control groups, there was a significant decrease in both pre-eclamptic and severe pre-eclamptic women and this was more prominent in the women with severe pre-eclampsia. When ELA, APLN and NO levels in the newborn venous-arterial cord blood of control group was compared with that of severe pre-eclamptic and pre-eclamptic women; it was parallel with maternal findings. ELA, APLN and NO levels appear to play a role in the pathophysiology of pre-eclampsia. It is predicted that if these molecules, which are reduced due to pre-eclampsia and severe pre-eclampsia, are brought to physiological limits in the future; pre-eclampsia related maternal and perinatal mortality and morbidity can be reduced. Impact Statement What is already known on this subject? There are two studies (one human and one animal) in the literature evaluating only maternal elabela (ELA) levels in pre-eclamptic pregnancies. The animal study demonstrated decreased blood ELA levels in pre-eclamptic animals and the human study found increased blood ELA levels in pre-eclamptic patients. There are no studies evaluating maternal ELA levels in severe pre-eclampsia patients and also there are no studies evaluating maternal ELA levels in pre-eclampsia and severe pre-eclampsia patients. There are no studies evaluating newborns' venous-arterial blood APLN and NO levels. Apelin (APLN) and nitric oxide (NO) results were controversial in pre-eclampsia and severe pre-eclampsia patients. What the results of this study add? The present study, for the first time, demonstrates that decreased blood ELA, APLN and NO levels in maternal blood of pregnant women with pre-eclampsia and severe pre-eclampsia and in their newborns' venous-arterial blood. Furthermore, we have also demonstrated for the first time that decreased ELA, APLN and NO are also related with low birth weights. What the implications are of these findings for clinical practice and/or further research? The low levels of ELA, APLN and NO in maternal blood and newborns' venous-arterial blood may be the result or the cause of pathologic changes in pre-eclampsia and severe pre-eclampsia. Also, ELA, APLN and NO may be new indicator parameters of systemic endothelial dysfunction together. More studies are needed to evaluate the relationship between of ELA, APLN and NO and pre-eclampsia and severe pre-eclampsia and in newborns' venous-arterial blood.

Nicotinamide Phosphoribosyltransferase Deficiency Potentiates the Antiproliferative Activity of Methotrexate through Enhanced Depletion of Intracellular ATP

Lower plasma nicotinamide phosphoribosyltransferase (NAMPT) levels are associated with improved response to methotrexate (MTX) in patients with juvenile idiopathic arthritis. Cell-based studies confirmed that reduced cellular NAMPT activity potentiates the pharmacologic activity of MTX; however, the mechanism of this interaction has yet to be defined. Therefore, in this study, we investigate the mechanism of enhanced pharmacologic activity of MTX in NAMPT-deficient A549 cells. Small interfering RNA-based silencing of NAMPT expression resulted in a greater than 3-fold increase in sensitivity to MTX (P < 0.005) that was completely reversed by supplementation with folinic acid. Despite a 68% reduction in cellular NAD levels in NAMPT-deficient cells, no change in expression or activity of dihydrofolate reductase was observed and uptake of MTX was not significantly altered. MTX did not potentiate the depletion of cellular NAD levels, but NAMPT-deficient cells had significant elevations in levels of intermediates of de novo purine biosynthesis and were 4-fold more sensitive to depletion of ATP by MTX (P < 0.005). Supplementation with hypoxanthine and thymidine completely reversed the antiproliferative activity of MTX in NAMPT-deficient cells and corresponded to repletion of the cellular ATP pool without any effect on NAD levels. Together, these findings demonstrate that increased MTX activity with decreased NAMPT expression is dependent on the antifolate activity of MTX and is driven by enhanced sensitivity to the ATP-depleting effects of MTX. For the first time, these findings provide mechanistic details to explain the increase in pharmacological activity of MTX under conditions of reduced NAMPT activity.

Relations of Apelin with Cardiac Remodeling in Patients with Hypertension and Type 2 Diabetes

Background: The peptide apelin has antihypertensive and antidiabetic properties, but its role in the processes of cardiac remodeling in patients with hypertension and type 2 diabetes (T2D) is poorly understood.

Aim: The aim of the study was to investigate apelin levels in patients with hyper-tension and T2D and to determine its relations to heart structural parameters and types of cardiac remodeling.

Materials and methods: We examined 63 patients with hypertension and T2D. Investigation complex included physical examination, standard transthoracic echocardiography and determination of apelin serum levels by ELISA. Control group consisted of 16 volunteers.

Results: The apelin levels in patients were significantly lower than those in volunteers (0.882(0.788; 0.924) ng/ml versus 1.097(0.944; 1.171) ng/ml, p<0.001). Negative correlation relations of apelin with septal wall thickness (r=−0.50, p<0.001), posterior wall thickness (r=−0.46, p<0.001), left ventricle (LV) mass (r=−0.39, p<0.01), LV mass index (r=−0.42, p<0.001) and left atrium size (r=−0.45, p<0.001) were found. In patients with concentric remodeling of LV apelin levels were 0.918 (0.892; 0.984) ng/ml, with concentric LV hypertrophy – 0.855(0.722; 0.899) ng/ml, with eccentric LV hypertrophy – 0.884(0.856; 0.929) ng/ml (p<0.05, p<0.001, p<0.001 versus control, respectively). Patients with concentric LV hypertrophy had significantly lower apelin levels than patients with concentric remodeling of LV (p<0.05).

Conclusion: Patients with hypertension and T2D have significant reduction of apelin blood levels, which is accompanied by cardiac remodeling development primarily concentric LV hypertrophy and have negative correlation relations of apelin with heart structural parameters that characterize LV remodeling and left atrium size.

Visfatin levels are increased in patients with resistant hypertension and are correlated with left ventricular hypertrophy

OBJECTIVE

The aim of this study was to investigate the possible correlation of serum visfatin levels with resistant hypertension (RHT).

PATIENTS AND METHODS

Patients who had undergone ambulatory blood pressure measurements (ABPM) during the outpatient controls were prospectively recruited. Seventy-one patients with RHT and 94 patients with controlled hypertension (CHT) were included in the study. RHT was defined as 'uncontrolled blood pressure (BP) despite using three antihypertensive agents including a diuretic or need of four or more drugs to control BP'. The demographic properties, medications used, and laboratory parameters including visfatin levels were recorded.

RESULTS

In the RHT group, left ventricular mass index was significantly higher compared with the CHT group (108.13±26.86 vs. 89.46±24.09 g/m, P<0.01). High-sensitivity C-reactive protein and visfatin levels were significantly higher in the RHT group [4.0 (5.2) vs. 2.3 (3.0) mg/l, P<0.01, and 12.87±4.98 vs. 9.46±4.69 ng/ml, P<0.01, respectively] compared with the CHT group. In the multivariate linear regression model, visfatin level remained as an independent predictor for office systolic BP [B: 2.07, 95% confidence interval (CI): 1.17-2.98, P<0.01]; office diastolic BP (B: 0.71, 95% CI: 0.27-1.16, P<0.01); mean 24-h systolic ABPM (B: 1.46, 95% CI: 0.79-2.13, P<0.01); and mean 24-h diastolic ABPM (B: 0.88, 95% CI: 0.42-1.34, P<0.01) and was also correlated independently with left ventricular mass index (B: 3.13, 95% CI: 2.58-3.99, P<0.01).

CONCLUSION

In this cohort of RHT patients diagnosed with ABPM, we have found an independent correlation between higher visfatin levels and the presence of RHT and left ventricular hypertrophy.

Treatment-associated change in apelin concentration in patients with hypertension and its relationship with left ventricular diastolic function

OBJECTIVE

We examined the change in apelin concentration and its relationship with left ventricular diastolic function in patients treated for hypertension.

METHODS

Ninety treatment-naive patients with newly diagnosed hypertension and 33 age- and sex-matched control subjects were prospectively enrolled. Patients with hypertension were randomized to treatment either with telmisartan 80 mg or amlodipine 10 mg. Apelin concentration was measured and echocardiography was performed at baseline and after 1 month of treatment.

RESULTS

The data of 77 patients and 33 controls were analyzed. Mean age, gender, baseline blood pressure, apelin levels, and echocardiographic measurements were similar between the treatment groups (p>0.05 for all). Apelin concentration was significantly lower in patients with hypertension than in controls. There was a significant increase in apelin level after 1 month of treatment in both groups (0.32±0.17 vs. 0.38±0.17 ng/dL in telmisartan group, p=0.009, and 0.27±0.13 vs. 0.34±0.18 ng/dL in amlodipine group, p=0.013). Diastolic function improved significantly in both groups (p<0.05) but was not significantly associated with change in apelin concentration.

CONCLUSION

Apelin concentration increased significantly after 1 month of effective treatment with telmisartan or amlodipine to a similar extent. Change in apelin concentration was not associated with improvement in diastolic function.