Cardiovascular Journal of Africa: Vol 28 No 3 (May/June 2017)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 3, May/June 2017

AFRICA

159

Saliva/serum ghrelin, obestatin and homocysteine levels

in patients with ischaemic heart disease

Nermin Kilic, Necati Dagli, Suleyman Aydin, Fazilet Erman, Yuksel Bek, Okhan Akin, SS Kilic, Haci

Kemal Erdemli, Hasan Alacam

Abstract

Background:

We aimed to compare ghrelin, obestatin, homo-

cysteine (Hcy), vitamin B

and folate levels in the serum and

saliva of ischaemic heart disease patients.

Methods:

Serum and saliva were collected from 33 ischaemic

heart disease (IHD) patients and 28 age- and body mass

index-matched healthy individuals. Levels of acylated and

desacylated ghrelin, obestatin and Hcy were determined using

the ELISA method.

Results:

Acylated ghrelin, desacylated ghrelin and obestatin

levels in the saliva were found to be higher than those in the

serum of the control group, while acylated and desacylated ghre-

lin levels in the saliva were significantly lower than those in the

serum. Obestatin levels were higher in IHD patients (

0.001).

Saliva and serum vitamin B

and folate levels in IHD patients

were significantly lower than in the control group (

0.001).

Conclusions:

It was determined that serum ghrelin levels

increased in ischaemic heart disease patients, while serum

levels of obestatin decreased.

Keywords:

saliva, homocysteine, ghrelin, obestatin, ischaemia

Submitted 10/1/15, accepted 17/7/16

Cardiovasc J Afr

2017;

: 159–164

www.cvja.co.za

DOI: 10.5830/CVJA-2016-075

Ischaemic heart disease (IHD) is the leading cause of death in

developing countries around the world.

It is characterised by

atherosclerosis, endothelial dysfunction, lipoprotein oxidation,

leukocyte infiltration, the release of various chemotactic and

growth factors, and accumulation of cholesterol, lipid and

calcium. Fatty streaks cause atherosclerotic plaques, lipid

accumulation, and acute and chronic luminal obstruction. The

resulting constriction of arteries leads to lack of sufficient

blood and oxygen supply to the target organs, which results in

ischaemia and necrosis in these organs.

2,3

Hormonal changes are

the main alterations that occur in ischaemic heart disease.

Recent studies have reported that ghrelin, the peptide

hormone, plays a host of physiological roles in the cardiovascular

system. Ghrelin, an endogenous ligand for the growth hormone

secretagogue receptor, is synthesised as a pre-prohormone

and then proteolytically processed to yield a 28-amino acid

peptide.

This peptide was reported to induce growth hormone

release; a wealth of evidence, however, has indicated many

other physiological activities of ghrelin, including regulation

of food intake and energy balance as well as of lipid and

glucose metabolism. Ghrelin receptors have been detected in the

hypothalamus and the pituitary, but also in the cardiovascular

system, where ghrelin exerts beneficial haemodynamic activities.

Ghrelin has been found to exert protective effects on the

cardiovascular system.

These include inhibition of vascular

endothelial cell apoptosis,

promotion of angiogenesis,

improvement of endothelial dysfunction, enhancement of

endothelial nitric oxide synthase (eNOS) expression,

reduction

of pro-inflammatory reactions in human endothelial cells, and

suppression of vascular inflammation.

The

-octanoylation at serine-3 is critical for ghrelin’s

activities. Previous studies have demonstrated that desacylated

ghrelin (D-ghrelin), unlike the standard form, does not inhibit

tumour necrosis factor-alpha (TNF-

)-induced interleukin-8

(IL-8) release.

11,12

It was reported in another study that obestatin, which

is encoded by the same gene as ghrelin, has a regulatory

function in the cardiovascular system.

Ghrelin is orexigenic,

whereas obestatin is anorexigenic; the former regulates body

fluid homeostasis, food intake and energy metabolism, while the

latter seems to induce the opposite effects.

The aetiology of endothelial injury relates to many factors,

including hyperlipidaemia, hypertension, diabetesmellitus, cigarette

smoking and various infectious agents. Elevated homocysteine

(Hcy) levels have also proven to be an underdiagnosed cause of

endothelial dysfunction. Hcy is a sulphur-containing amino acid

involved in two metabolic pathways, catalysed by cystathionine-

synthase andmethionine synthase, depending on vitaminB

, B

and

folate levels and enzymatic activity of methylenetetrahydrofolate.

Previous studies demonstrated thatHcy decreased endothelium-

dependent vasorelaxation and eNOS reactivity, causing endothelial

Department of Medical Biochemistry, School of Medicine,

Ondokuz Mayis University, Samsun, Turkey

Nermin Kilic, MD

Department of Cardiology, School of Medicine, Firat

University, Elazig, Turkey

Necati Dagli, MD

Department of Medical Biochemistry, School of Medicine,

Firat University, Elazig, Turkey

Suleyman Aydin, MD

Fazilet Erman, MD

Department of Biostatistics, School of Medicine, Ondokuz

Mayis University, Samsun, Turkey

Yuksel Bek, MD

Biochemistry Laboratory, Kecioren Education and

Research Hospital, Ankara, Turkey

Okhan Akin, MD

Department of Infectious Diseases and Microbiology,

Training and Research Hospital, Samsun, Turkey

SS Kilic, MD

Department of Medical Biochemistry, Corum Training and

Research Hospital, Corum, Turkey

Haci Kemal Erdemli, MD

Department of Medical Biochemistry, School of Medicine,

Hacettepe University, Ankara, Turkey

Hasan Alacam, MD,

hasanalacam@hotmail.com