Cardiovascular Journal of Africa: Vol 25 No 5 (September/October 2014)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 5, September/October 2014 200 AFRICA
Cardiovascular Topics
Diagnostic value of plasma C-type natriuretic peptide
levels in determination of the duration of mesenteric
ischaemia
Sinan Demirtas, Oguz Karahan, Suleyman Yazici, Orkut Guclu, Ahmet Caliskan, Orhan Tezcan, Celal Yavuz
Abstract
Objective: Mesenteric arteries release C-type natriuretic
peptide (CNP), which hyperpolarises vascular smooth muscle.
We measured the levels of this peptide after inducing mesen-
teric ischaemia over a series of time intervals, so as to deter-
mine its predictive value in demonstrating the severity of
ischaemia in a rat model.
Methods: A total of 32 rats were allocated to four groups
containing eight rats each. Basal CNP reference levels were
measured in the control group, which was not exposed to any
intervention. In groups I, II and III, mesenteric ischaemia
was induced over three, six and nine hours, respectively, and
plasma CNP levels were measured afterwards. Mesenteric
ischaemia was induced by clamping the superior mesenteric
artery.
Results: In comparison with the controls (2.38 ± 0.18 pg/ml),
CNP levels were relatively lower in group I (2.54 ± 0.42 pg/
ml). However, significant increases in plasma CNP levels were
observed over longer periods of ischaemia in group II, at 5.23
± 0.22 pg/ml, and in group III, at 6.19 ± 0.67 pg/ml (p < 0.05).
A significant direct relationship was determined between
plasma CNP levels and prolonged intervals of mesenteric
ischaemia ( R = 0.56, p < 0.001).
Conclusion: Measuring plasma CNP levels in patients with
acute mesenteric ischaemia may be beneficial in estimating
the time period over which the ischaemic injury has occurred.
Keywords: C-type natriuretic peptide, mesenteric ischaemia,
ischaemia duration
Submitted 3/4/14, accepted 4/6/14
Cardiovasc J Afr 2014; 25: 200–203
DOI: 10.5830/CVJA-2014-033
Acute mesenteric ischaemia (AMI) causes significant morbidity
and mortality if not promptly diagnosed and treated. If medical
interventions are delayed, the patient may sustain serious
ischaemic injury leading to bowel necrosis, so large segments
of bowel may require surgical resection. Often these patients
have poor clinical outcomes and suffer from complications such
as malnutrition. 1,2 Mesenteric ischaemia makes up 0.1% of all
hospital admissions.1 Even though technological advances have
been made in diagnostic laboratory and imaging techniques,
AMI remains fatal in 60% of patients diagnosed with this
condition.1,3
Scientists have been investigating whether there are specific
sensitive biomarkers that may indicate the presence of AMI.2,4
Several endothelial markers have been identified as putative
biomarkers that may reveal the severity and duration over which
mesenteric ischaemia has been sustained.5 However, markers
that are effective enough for use in clinical practice have yet to
be identified.
Natriuretic peptides, namely atrial natriuretic peptide (ANP),
brain natriuretic peptide (BNP), and C-type natriuretic peptide
(CNP) function in maintaining fluid and electrolyte balance as
well as blood vessel tone. CNP is released by vascular endothelial
cells, and this biomarker’s function in influencing vascular tone
has been investigated.6,7 It has been hypothesised that CNP is
an endothelium-derived hyperpolarising factor (EDHF) that
specifically affects the degree of resistance in the mesenteric
arteries.8 In this study, we aimed to investigate plasma CNP levels
during early and advanced stages of mesenteric ischaemia so as
to determine whether CNP levels are a good indicator of severity
of AMI in a rat model.
Methods
The study protocol was created in accordance with the Animal
Welfare Act and the Guide for the Care and Use of Laboratory
Animals created by the university ethics committee. The rats
were obtained and housed in the laboratory of the University’s
animal production unit. They were maintained in a controlled
environment with 12-hour light–dark cycles, and the cages were
kept at a constant humidity of 50 ± 5% and temperature of 22
± 2°C.
A total of 32 male Sprague-Dawley rats between the ages of
eight and 12 weeks and weighing 230 ± 30 g (mean ± standard
deviation) were randomly allocated to four different groups.
The induction of sedation was achieved with an intraperitoneal
Medical School of Dicle University, Department of
Cardiovascular Surgery, Diyarbakir, Turkey
Sinan Demirtas, MD,
Oguz Karahan, MD
Suleyman Yazici, MD
Orkut Guclu, MD
Ahmet Caliskan, MD
Orhan Tezcan, MD
Celal Yavuz, MD