Urocortin 2 infusion in human heart failure Clinical research

Clinical research
European Heart Journal (2007) 28, 2589–2597
doi:10.1093/eurheartj/ehm340
Heart failure/cardiomyopathy
Urocortin 2 infusion in human heart failure
Mark E. Davis, Christopher J. Pemberton, Timothy G. Yandle, Steve F. Fisher, John G. Lainchbury,
Christopher M. Frampton, Miriam T. Rademaker, and Mark Richards*
Christchurch Cardioendocrine Research Group, Department of Medicine, Christchurch School of Medicine and Health
Sciences, PO Box 4345, Christchurch 8140, New Zealand
Received 28 February 2007; revised 5 July 2007; accepted 17 July 2007; online publish-ahead-of-print 25 August 2007
See page 2561 for the editorial comment on this article (doi:10.1093/eurheartj/ehm413)
KEYWORDS
Hormones;
Cardiac output;
Haemodynamics;
Echocardiography;
Vasodilation
Introduction
Urocortin 2 (UCN2) is a vasoactive peptide belonging to the
corticotrophin-releasing factor (CRF) peptide family.1 CRF
and the urocortins (UCNs) 1, 2, and 3 act through
G-protein-coupled receptor subtypes, CRF1 and CRF2.2 CRF
activates CRF1 receptors, urocortin 1 (UCN1) binds to both
CRF1 and CRF2 receptors, whereas UCN2 and urocortin 3
(UCN3) are selective agonists for the CRF2 receptors, of
which there are at least two variants, termed CRF2(a) and
CRF2(b). The CRF2(a) receptor is found in high concentration
in the human left ventricle, intramyocardial blood vessels,
and medial layers of internal mammary arteries.3–5
Recent reports indicate that the UCNs exert effects
beyond the hypothalamo-pituitary-adrenal axis, directly
upon cardiac, vascular, and vaso-humoral function in
health and cardiac disease.6–11 UCN2 infusion in healthy
humans induces increases in cardiac output (CO) and left
ventricular ejection fraction (LVEF) and decreases systemic
vascular resistance (SVR).12 Activation of renin, angiotensin
II, and norepinephrine occurred only with high-dose UCN2,
with its more powerful haemodynamic effects in company
with a modest fall-off in urine volume and sodium and potassium excretion. This parallels effects reported in normal
* Corresponding author. Tel: þ64 33641116; fax: þ64 33641115.
E-mail address: mark.richards@cdhb.govt.nz
sheep but contrasts with the pronounced suppression of
volume retaining, vasoconstrictor neurohormonal systems,
and augmentation of renal function observed in experimental ovine heart failure (HF).7 In intact mice, both wild type
and in the muscle-specific LIM protein-deficient HF model,
UCN2 is positively inotropic, chronotropic, and lusitropic.10
In isolated rat heart, UCN1, UCN2, and UCN3 reduce infarct
size in cardiac ischaemia/reperfusion experiments.11,13
These reports suggest that UCN has an important role in
volume/pressure homeostasis in health and heart disease.
We report the haemodynamic, echocardiographic, neurohumoral, and renal effects of UCN2 infused in human HF.
Methods
Subjects
We studied eight males with stable congestive cardiac failure
(six with ischaemic heart disease and two with idiopathic dilated
cardiomyopathy, all with LVEF 40%, NYHA functional class II–III
(seven class II and one class III]), plasma creatinine , 1.7 mg/dL
(,0.15 mmol/L, range 0.08–0.11; mean 0.10 + 0.01 mmol/L), aged
43–69 (mean + SD, 61.2 + 9.8) years, weighing 78–112 (mean 97 +
11) kg, with body mass index of 26–39 (mean 33.1 + 4.3), echocardiographic LVEF of 21–39 (mean 32.9 + 5.7%), and amino terminal
pro-brain natriuretic peptide (NTproBNP) of 338 + 279 pg/mL.
Subjects were taking an angiotensin-converting enzyme-inhibitor
(ACE-I) (n ¼ 6) or angiotensin II receptor blocker (n ¼ 1), or both
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2007.
For permissions please email: journals.permissions@oxfordjournals.org.
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Aims To document the haemodynamic, neurohormonal, and renal responses to Urocortin 2 (UCN2)
infused in human heart failure (HF).
Methods and results Eight male patients with HF [left ventricular ejection fraction (LVEF) , 40%, NYHA
class II–III] received placebo and 25 [low dose (LD)] and 100 mg [high dose (HD)] of UCN2 intravenously
over 1 h in a single-blind, placebo-controlled, dose-escalation design.
UCN2 increased cardiac output (CO) (mean peak increments + SEM; placebo 0.3 + 0.1; LD 1.0 + 0.3;
HD 2.0 + 0.2 L/min; P , 0.001) and LVEF (0.0 + 1.5; LD 5.9 + 2.1; HD 14.1 + 2.7%; P ¼ 0.001)
and decreased mean arterial pressure (placebo 6.7 + 1.3; LD 11.4 + 1.7; HD 19.4 + 3.3 mmHg;
P ¼ 0.001), systemic vascular resistance (SVR) (placebo 104 + 37; LD 281 + 64; HD 476 + 79 dynes
s/cm5; P , 0.003), and cardiac work (CW) (placebo 48 + 12; LD 66 + 22; HD 94 + 13 mmHg/L/min;
P , 0.001). No significant effect on vasoconstrictor/volume-retaining neurohormones was noted.
UCN2 decreased urinary volume (P ¼ 0.035) but not creatinine excretion (P ¼ 0.962).
Conclusion Intravenous UCN2 in HF induced increases in CO and LVEF with falls in SVR and CW. No
hormone response occurred. The role of UCN2 in circulatory regulation and its potential therapeutic
application in heart disease warrant further investigation.
2590
(n ¼ 1). Seven were receiving a beta-blocker, six a loop diuretic,
and one spironolactone. Medications were taken at breakfast
2–3 h prior to infusion.
Study protocol
for subsequent analysis of left ventricular volumes (diastolic and systolic) and LVEF, transmitral early diastolic flow velocity (E), transmitral deceleration time (DT), early diastolic myocardial velocity (Em),
diastolic myocardial velocity during atrial contraction (Am), and systolic myocardial velocity (Sm). Transmitral flow was measured by
pulse wave Doppler at the mitral valve leaflet tips in the fourchamber view. Tissue Doppler myocardial velocities at the medial
mitral valve annulus were measured using the machine presets.
Left ventricular wall motion score index (LVWMSi) was obtained
using the established 16-segment method.16 Cardiac work (CW) was
calculated as the product of CO and mean arterial pressure (MAP).
Twelve-lead electrocardiograms (ECGs) (Angilent Pagewriter 200,
Angilent Technologies, Andover, MA, USA) were recorded at 0900,
1000, 1400, and 1800 h. PR interval, QRS duration, and QT interval,
both uncorrected and corrected (QTc using Fridericia’s method, QT/
RR1/3), were assessed.
Human urocortin 2 two-site ELISA assay
UCN2 was measured in a two-site chemiluminescent ELISA, using an
N-terminal-directed monoclonal antibody for plate coating and a
C-terminal-directed rabbit polyclonal antibody. Antisera were
donated by Neurocrine Biosciences Incorporated. Mouse anti-rabbit
IgG-Alkaline Phosphatase conjugate plus CSPDw substrate (Applied
Biosystems, Foster City, CA, USA) were used to generate the chemiluminescent signal. Samples diluted parallel to the standard curve.
Mean recovery of UCN2 was 107% at 2.43 ng/mL, 100% at 1.21 ng/
mL, and 100% at 0.61 ng/mL. The lower limit of quantitation
(LOQ) was 0.3 ng/mL. The assay detection limit (upper 95% CI for
the zero standard) was 0.11 ng/mL (n ¼ 36). We have used all the
assay data for statistical calculations and reported 95% CI. The
intra and (inter) assay CVs (n ¼ 36) were 5.0% (5.7%) at 0.68 ng/
mL, 2.8% (5.7%) at 1.34 ng/mL, and 2.8% (3.9%) at 2.45 ng/mL.
Cross-reactivities were determined by measurement of human
UCN1, UCN3, and CRF at 510, 670, and 500 ng/mL, respectively,
all evoking assay responses at or below the LOQ (0.3 ng/mL).
UCN1 and CRF responses were also at or below the 95% CI for the
zero standard.
Statistics
Data were analysed by repeated measures analysis of variance
(ANOVA), using SPSS version 11.5 statistical package (SPSS Inc.,
Chicago, IL, USA). The significance reported for both overall dose
effect and between pairs of study phases (i.e. placebo vs. 25 mg,
placebo vs. 100 mg, and 25 vs. 100 mg) is the time-by-dose interaction from commencement of infusion to 1 h post-infusion unless
otherwise stated. This period represents the infusion time plus
four times the UCN2 half life (t12). Where significant differences
between doses were identified, paired comparisons were undertaken using Fisher’s protected LSD test. UCN2 t12, metabolic clearance rate (MCR), and volume of distribution (VD) were calculated
using a one-compartment model (WinNonLin Professional 3.1, Pharsight Corporation, Mountain View, CA, USA). Geometric means
and 95% CI are tabulated for non-normally distributed hormone
measures. Other results are presented as mean + SEM. For clarity,
pooled 95% CI are displayed for the graphed hormones and pooled
SEM for the graphed haemodynamics. A value of P , 0.05 was
taken to indicate statistical significance.
Results
Urocortin 2 infusion
Plasma UCN2 concentrations increased in a dose-related
fashion from 230 (40–420) to 1390 (1210–1590) pg/mL and
5360 (4650–6070) pg/mL with placebo and 25 and 100 mg
doses, respectively (P , 0.001 for both doses compared
with time-matched placebo control values). Plasma cAMP
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The protocol was approved by the Ethics Committee of the New
Zealand Ministry of Health (Upper South B, Canterbury). Participants gave written informed consent. Human UCN2 (the 38 amino
acid sequence predicted by Reyes et al.14) was provided by Neurocrine Biosciences Inc. (San Diego, CA, USA), manufactured by
Bioserv Corporation (San Diego, CA, USA). Subjects were studied
using a single-blind dose-escalation design, receiving placebo and
25 and 100 mg UCN2 sequentially with a washout period of 2–5
weeks between each dose. On day 3 of metabolic diets (sodium
120 and potassium 100 mmol per day), subjects ate breakfast and
presented to the study room by 0700 h. A 24 h urine collection was
completed at 0800 h. The subjects fasted until lunch at 1300 h.
Participants were weighed and 5 mL/kg water was given orally at
0800 h followed by 100 mL/h between 0900 and 1800 h. Subjects
were seated except when standing to collect urine samples. At
0815 h, venous cannulae were placed in each forearm, one for the
infusion of UCN2 or placebo, and the other for blood sampling. All
subjects received vehicle placebo (dissolved in 1 mL water, then
made up to 60 mL in normal saline with 50 mL administered), 25 mg
UCN2 [1 mg dissolved in 6.6 mL water, then 0.2 mL of that solution
made up to 60 mL in normal saline (0.5 mg/mL) with 50 mL
administered], and finally 100 mg UCN2 [1 mg dissolved in 5 mL water,
then 0.6 mL of that solution made up to 60 mL in normal saline
(2 mg/mL) with 50 mL administered] over 1 h commencing at 0900 h.
Blood for hormone assays (drawn at 0830, 0900, 0930, 1000, 1100,
1400, and 1800 h) was collected into chilled tubes containing EDTA
except for cortisol (heparin) and angiotensin II (0.125 M EDTA,
0.05 M o-phenanthroline, 2% ethanol, 0.2% neomycin sulphate, and
0.03 mg/mL enalkiren) samples. Samples were centrifuged at 48C
and plasma stored at 2808C before assay for UCN2, cAMP, cyclic
guanosine monophosphate (cGMP), adrenocorticotrophic hormone
(ACTH), cortisol, plasma renin activity (PRA), angiotensin II,
aldosterone, arginine vasopressin (AVP), NTproBNP, epinephrine,
norepinephrine, endothelin 1, adrenomedullin, insulin, and ghrelin
according to our published methods.15
At the conclusion of infusions, additional samples (for UCN2 pharmacokinetics) were taken at 1005, 1010, 1015, and 1020 h. For each
hormone, all samples from an individual were analysed in a single
assay. Numbers of UCN2 samples were too great to fit into one
assay but samples from the 25 and 100 mg UCN2 active phases
were assayed together. Intra and inter-assay coefficients of variation (CVs) were all ,18.5%.
Plasma sodium (Naþ), potassium (Kþ), creatinine, glucose, venous
bicarbonate, and chloride (Cl2) were measured at 0900, 1000, 1100,
1300, 1400, 1500, and 1800 h with measurement of calcium (Ca2þ),
magnesium, phosphate, total protein, albumin, aspartate transaminase (AST), alanine transaminase (ALT), amylase, creatine kinase
(CK), CK-MB fraction, and troponin T (TnT) at the 0900 and 1800 h
time points.
After blood sampling, subjects stood to collect urine (0900, 1000,
1100, 1400, and 1800 h) for measurement of volume, cAMP, cGMP,
Naþ, Kþ, and creatinine. Systolic and diastolic blood pressure (SBP
and DBP), heart rate (HR), and pulse oximetry were recorded at
0830 h, every 15 min from 0900–1100 h, then hourly until 1800 h,
with an automatic sphygmomanometer and pulse oximeter (Pro
300 monitor, Dinamap, Critikon, Tampa, Florida, USA). CO was
measured by the thoracic impedance method (Minnesota impedance
cardiography, model 304B, Surcom Inc., Minneapolis, MN, USA)
every 30 min from 0830 to 1100 h, and then hourly until 1800 h.
Echocardiography was performed 1 h before and immediately after
infusions (Vivid 3 echocardiogram; General Electric, Fairfield, CT,
USA). Left ventricular volume was measured in the four-chamber
view, using the modified Simpson’s rule. Data were stored digitally
M.E. Davis et al.
Urocortin 2 infusion in human heart failure
tended to increase (P ¼ 0.087; placebo compared with
100 mg dose) (Figure 1).
Pharmacokinetics
The t12; for immunoreactive UCN2 (median, IQR) was 15.5
(11.4–125.4) min, MCR 0.09 (0.02–0.32) L/min, and VD 3.4
(1.9–5.4) L.
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Haemodynamics and echocardiography
UCN2 increased CO (maximal increments from pre-infusion
levels were 0.3 + 0.1, and 1.0 + 0.3 and 2.0 + 0.2 L/min
for placebo, 25 and 100 mg doses, respectively, P , 0.001
for both doses compared with placebo). Corresponding
increments in HR were 1.8 + 0.8, and 4.1 + 0.9 and 6.8 +
1.0 b.p.m., P , 0.001. UCN2 decreased SBP (maximal
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Figure 1 Change from commencement of urocortin 2 infusion in plasma urocortin 2, cyclic adenosine monophosphate, N-terminal pro-brain natriuretic peptide,
ACTH, and adrenomedullin (geometric mean and pooled 95% confidence intervals) to urocortin 2 infusion in eight male humans with mild heart failure. Urocortin
2 infusion occurred between time 0 and 1 h. ‘Dose comparison’ refers to overall assessment of differences between doses by ANOVA of time by dose interaction.
Placebo vs. 25 mg, placebo vs. 100 mg, and 25 vs. 100 mg refer to comparison of placebo with individual active doses and between the two active doses (25 and
100 mg). Pooled 95% confidence intervals are displayed at the right upper corner in each panel.
2592
M.E. Davis et al.
decrements 210.6 + 1.9, and 211.9 + 2.5 and 222.6 +
4.6 mmHg, P , 0.001), DBP (25.9 + 1.3, and 211.6 + 1.6
and 218.6 + 2.7 mmHg, P , 0.001), and MAP (26.7 + 1.3,
and 211.4 + 1.7 and 219.4 + 3.3 mmHg, P , 0.001). SVR
fell 2104 + 37, and 2281 + 64 and 2476 + 79 dynes
s/cm5, P ¼ 0.003, as did CW 36 + 5, and 254 + 25 and
277 + 17 L mmHg/min, P , 0.001. Sustained post-infusion
decreases in SVR, CW, and arterial pressure were observed,
with longer lasting and more clear-cut effects from the
100 mg compared with the 25 mg dose (Figures 2 and 3).
With higher dose UCN2, increases in LVEF and E were
observed while LVWMSi decreased (Figures 4 and 5). No significant changes were seen in A, DT, Em, Am, Sm, or E/Em
(data not shown).
Neurohormones
UCN2 infusion induced significant increases in NTproBNP,
ACTH, and ADM (Figure 1). UCN1, PRA, angiotensin II, AVP,
aldosterone, epinephrine, norepinephrine, cortisol, cAMP,
cGMP, ghrelin, insulin, or endothelin-1 was not significantly
altered by either dose of UCN2 (Figure 1 and Table 1).
Plasma biochemistry
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A subtle elevation (from 0.09 + 0.01 to 0.10 + 0.01 mmol/L,
P ¼ 0.045) in plasma creatinine was observed during and in
the hour after the 100 mg UCN2 infusion. UCN2 infusion did
not alter plasma Naþ, Kþ, glucose, venous bicarbonate,
Cl2, Ca2þ, magnesium, phosphate, total protein, albumin,
AST, ALT, amylase, CK, CK-MB, and TnT during this period
(results not shown).
Urinalysis
UCN2 infusion induced no change for the period of infusion
and for the subsequent hour in urinary volume, excretion
of sodium, potassium, creatinine, cAMP, or cGMP. If the
whole observation period was considered, UCN2 infusion
induced subtle but significant dose-related decreases
in urinary volume (P ¼ 0.005) and sodium excretion
(P , 0.001) (Table 2).
Electrocardiogram
UCN2 did not change PR interval, QRS duration, and QT or
QTc intervals. No arrhythmic effect of UCN2 was observed.
Observed events
All volunteers flushed during infusions of UCN2. This subsided within 2 h of the end of infusions.
Discussion
We provide the first report on UCN2 infused in human HF.
Infusions of 25 and 100 mg UCN2 markedly elevated plasma
UCN2, which had a t12 of 15 min, MCR of 0.09 L/min, and a
VD of 3.4 L.
Figure 2 Cardiac output, heart rate, systemic vascular resistance, and
cardiac work responses (mean and pooled standard errors) to urocortin 2 infusion in eight male humans with mild heart failure. Lunch was taken after the
4 h observations. Infusion time and statistical comparisons as per Figure 1.
Pooled SEM is displayed to upper or lower right in each panel.
Haemodynamic status
We observed a dose-related increase in CO substantially secondary to decreased after-load through vasodilatation (as
evidenced by decreases in SVR and flushing in all subjects
at both doses) and a small increase in HR. Whether a positive
inotropic effect by UCN2 also contributed to the increase in
CO is uncertain. Our data cannot address this question as
loading conditions and HR were not fixed. However, UCN2
has a positive inotropic effect in the isolated mouse heart,
Urocortin 2 infusion in human heart failure
2593
Figure 4 Left ventricular end-diastolic volume, end-systolic volume, and
ejection fraction responses (mean + SEM) to urocortin 2 infusion in eight
male humans with mild heart failure. Infusion time and statistical comparisons as per Figure 1.
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Figure 3 Systolic, mean arterial, and diastolic blood pressure responses
(mean and pooled standard errors) to urocortin 2 infusion in eight male
humans with mild heart failure. Infusion time and statistical comparisons as
per Figure 1. Pooled SEM is displayed to the mid-right of each panel.
and in rabbit ventricular myocytes via CRF(2) receptormediated stimulation of protein kinase A (PKA).10,17 The
CO increment is less marked than previously observed with
the same dosing regimen in healthy volunteers.12 Presumably, this reflects underlying ventricular impairment and
the effects of drug therapy.
The marked decreases in SBP and DBP with only minor
increments in HR reflected a vasodilator effect on a background of HF-related blunting of baroreceptor responses
together with medications (e.g. beta blockade) that may
also reduce reflex responses to falls in blood pressure. This
contrasts with our findings in normal humans in whom
there was no change in SBP, with UCN2 infusion at the
same doses. It is possible that the greater increase in CO
in normal subjects counterbalanced the effect of the vasodilatory response on systolic pressures, the net result being
Figure 5 Transmitral early diastolic flow velocity (E) and left ventricular
wall motion score index responses (mean + SEM). Infusion time and statistical
comparison as per Figure 1.
minimal change in SBP.12 The sustained nature of the falls
in arterial pressure and SVR suggests changes in intracellular
signalling with longer activity than the period of elevated
plasma UCN2. Multiple vasodilator mechanisms are reported
for the UCNs. UCN2 acts via cAMP/PKA and p38 mitogenactivated protein kinase in rat aortic ring18 and causes
endothelium-independent vasodilatation in human internal
mammary artery in vitro.5 UCN1 induces vasodilatation in
rat coronary artery via activation of PKA-dependent vascular
Ca2þ-activated Kþ channels19 (although a conflicting report
suggests a PKC-mediated mechanism20), and in human
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Table 1 Effect of urocortin 2 infusion on plasma hormones in eight human males with mild heart failure
Time (h)
0900 Infusion 1000
PRA (nmol/L/h)
Pl
25 mg
100 mg
Angiotensin II
Pl
(pmol/L)
25 mg
100 mg
Aldosterone (pmol/L) Pl
25 mg
100 mg
AVP (pmol/L)
Pl
25 mg
100 mg
Cortisol (nmol/L)
Pl
25 mg
100 mg
cGMP (nmol/L)
Pl
25 mg
100 mg
Epinephrine (pmol/L) Pl
25 mg
100 mg
Norepinephrine (pmol/ Pl
L)
25 mg
100 mg
Insulin (pmol/L)
Pl
25 mg
100 mg
Ghrelin (pmol/L)
Pl
25 mg
100 mg
Endothelin-1 (pmol/L) Pl
25 mg
100 mg
UCN1 (pmol/L)
Pl
25 mg
100 mg
0
0.5
1
1.5
6.9 (1.7–27.0)
5.1 (1.0–26.1)
7.5 (1.7–33.1)
15.6 (2.1–29.1)
9.2 (7.1–11.4)
10.4 (8.6–12.5)
174 (110–274)
151 (106–215)
163 (106–251)
2.8 (1.5–5.3)
2.3 (1.5–3.5)
2.4 (1.7–3.5)
336 (241–469)
265 (211–334)
291 (206–410)
4.5 (3.1–6.5)
4.1 (2.8–6.1)
4.2 (2.8–6.4)
156 (93–260)
126 (86–186)
110 (79–153)
4137 (2050–6225)
2915 (2312–3517)
2997 (2225–3769)
99 (66–151)
114 (65–200)
130 (80–212)
111 (70–177)
110 (59–202)
107 (61–189)
1.5 (1.2–1.8)
1.6 (1.2–2.0)
1.5 (1.1–2.0)
10.6 (9.3–12.2)
10.2 (8.9–11.8)
9.2 (8.2–10.5)
10.8 (3.1–38.2) 6.4 (1.5–27.3)
10.3 (2.8–38.4) 6.6 (1.1–41.0)
12.9 (3.2–52.8) 13.3 (3.5–50.6)
15.9 (3.8–27.9)
14.5 (6.6–22.4)
13.8 (9.7–17.8)
160 (110–232)
132 (79–220)
177 (99–317)
2.0 (1.3–3.3)
2.3 (1.3–4.1)
3.4 (1.9–6.1)
294 (226–382) 296 (209–420)
250 (205–306) 228 (194–269)
302 (208–438) 301 (218–417)
3.8 (2.8–5.2)
4.0 (3.1–5.3)
3.7 (2.7–5.0)
3.6 (2.6–5.1)
3.7 (2.9–4.7)
4.0 (3.1–5.1)
136 (87–213)
102 (65–159)
150 (93–242)
3526 (1858–5174)
3145 (2444–3845)
3791 (2996–4585)
85 (54–134)
78 (47–128)
78 (52–116)
72 (44–118)
77 (50–119)
76 (57–101)
115 (74–178)
124 (81–189)
108 (61–192)
119 (71–202)
123 (74–205)
121 (77–189)
1.7 (1.3–2.1)
1.8 (1.4–2.3)
2.0 (1.6–2.4)
11.1 (9.5–13.0) 11.5 (10.0–13.2)
11.2 (9.7–12.8) 11.5 (10.2–13.0)
10.5 (9.2–11.9) 11.5 (10.2–12.9)
2
9.9 (2.8–34.4)
10.2 (2.7–38.2)
14.1 (3.6–54.3)
5.8 (1.4–23.3)
4.6 (1.1–18.1)
9.6 (2.5–36.7)
16.4 (21.9 to 34.7)
13.5 (6.2–20.8)
14.1 (9.9–18.3)
170 (101–284)
146 (91–232)
174 (90–338)
2.5 (1.6–3.9)
2.0 (1.4–3.0)
2.4 (1.7–3.2)
347 (285–423)
318 (233–435)
225 (174–291)
203 (175–235)
368 (263–514)
311 (214–453)
4.1 (3.0–5.8)
3.7 (2.9–4.8)
4.6 (3.1–6.9)
4.0 (2.6–6.2)
4.3 (3.4–5.5)
3.5 (2.4–4.9)
138 (87–220)
113 (75–171)
88 (62–125)
3649 (2224–5074)
3008 (2499–3517)
3156 (2394–3918)
74 (41–135)
71 (42–121)
76 (47–123)
70 (45–111)
110 (80–152)
89 (54–146)
122 (80–186)
126 (83–191)
110 (67–180)
113 (68–186)
118 (75–186)
121 (79–185)
1.7 (1.5–1.9)
1.8 (1.5–2.3)
2.3 (1.8–2.9)
13.0 (11.5–14.6) 12.6 (11.2–14.1)
13.4 (12.0–15.0) 11.7 (10.5–13.1)
13.2 (12.1–14.3) 11.8 (10.8–12.8)
3
9.7 (3.2–28.9)
6.8 (2.0–22.5)
8.2 (2.2–30.4)
5
12.5 (3.8–41.6)
8.5 (2.9–25.0)
8.4 (2.6–27.2)
26.8 (23.1 to 56.7)
14.8 (7.8–21.8)
14.5 (6.4–22.5)
165 (109–249)
158 (102–244)
143 (89–229)
2.0 (1.5–2.7)
1.7 (1.4–2.1)
2.0 (1.6–2.6)
325 (230–461)
352 (271–456)
310 (229–421)
302 (219–416)
312 (221–441)
237 (141–398)
3.6 (2.8–4.7)
3.7 (2.6–5.1)
4.1 (2.8–6.0)
3.7 (2.6–5.1)
4.0 (2.7–5.9)
3.9 (2.9–5.2)
140 (97–203)
111 (75–165)
101 (74–138)
3621 (2171–5072)
3540 (2385–4696)
3115 (2311–3919)
64 (33–124)
580 (267–1260)
63 (41–99)
534 (235–1217)
72 (44–119)
492 (161–1499)
122 (78–190)
105 (66–167)
117 (74–185)
103 (64–167)
114 (73–179)
117 (74–185)
1.7 (1.4–2.1)
1.7 (1.5–2.0)
1.8 (1.5–2.3)
13.2 (11.8–14.7) 11.9 (10.4–13.5)
12.0 (10.8–13.3) 11.1 (9.7–12.7)
11.6 (10.4–12.9) 10.8 (9.3–12.7)
9
DC
6.3 (2.2–17.5)
5.2 (1.7–15.8)
3.4 (1.0–12.2)
23.1 (6.1–40.2)
15.6 (11.9–19.2)
14.2 (10.4–18.1)
208 (141–308)
205 (143–295)
178 (108–291)
1.9 (1.3–2.7)
2.0 (1.3–3.2)
2.0 (1.5–2.5)
180 (106–305)
200 (140–286)
212 (145–309)
4.8 (3.6–6.6)
4.8 (3.5–6.6)
5.5 (4.0–7.5)
221 (151–323)
235 (174–318)
179 (122–263)
4054 (2047–6060)
2930 (2038–3822)
2884 (2208–3559)
130 (86–196)
152 (99–234)
153 (102–230)
114 (71–184)
121 (72–204)
121 (72–203)
1.9 (1.7–2.3)
1.8 (1.5–2.2)
2.0 (1.6–2.5)
9.0 (8.1–10.1)
8.7 (7.9–9.5)
8.9 (8.0–9.8)
0.557
0.212
0.613
0.28
0.191
0.206
0.524
0.062
0.085
0.337
0.060
0.147
M.E. Davis et al.
Values are displayed as geometric means (95% confidence intervals); time 0 indicates commencement of the infusion; participants ate lunch 3 h post-infusion. Pl, placebo; PRA, plasma renin activity; AVP, arginine
vasopressin; NTproBNP, N-terminal pro-brain natriuretic peptide; DC, dose comparison.
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Urocortin 2 infusion in human heart failure
2595
Table 2 Effect of urocortin 2 infusion on urine biochemistry in eight human males with mild heart failure
Infusion
Urine volume (mL/h)
Sodium (mmol/h)
Potassium (mmol/h)
Creatinine (mmol/h)
Time (h)
21 to 20
0 to 1
1 to 2
2 to 5
5 to 9
DC 0 to 2 h
DC 0 to 9 h
Pl
25 mg
100 mg
Pl
25 mg
100 mg
Pl
25 mg
100 mg
Pl
25 mg
100 mg
189 + 61
153 + 37
151 + 47
15.7 + 5.4
7.7 + 3.2
10.5 + 4.4
2.1 + 0.4
1.7 + 0.5
2.7 + 0.6
0.22 + 0.11
0.46 + 0.30
0.37 + 0.15
229 + 57
128 + 34
72 + 22
13.0 + 2.9
5.8 + 1.8
3.8 + 1.3
1.7 + 0.3
1.2 + 0.3
1.8 + 0.4
0.22 + 0.15
0.38 + 0.27
0.39 + 0.17
123 + 23
196 + 32
74 + 25
7.8 + 1.9
8.4 + 1.8
2.7 + 0.7
1.9 + 0.6
1.3 + 0.3
1.4 + 0.3
0.24 + 0.14
0.31 + 0.20
0.33 + 0.16
93 + 22
118 + 31
130 + 40
4.9 + 1.4
4.4 + 1.3
7.3 + 2.1
0.7 + 0.3
0.6 + 0.3
0.6 + 0.2
0.14 + 0.06
0.12 + 0.05
0.12 + 0.06
109 + 20
177 + 15
170 + 25
2.9 + 0.6
4.6 + 1.0
4.3 + 0.8
0.1 + 0.1
0.1 + 0.1
0.1 + 0.1
0.03 + 0.01
0.03 + 0.01
0.03 + 0.01
0.504
0.005
0.605
,0.001
0.254
0.300
0.344
0.936
Values are displayed as mean + SEM; time 0 indicates commencement of the infusion; participants ate lunch 3 h post-infusion. Pl, placebo; DC, dose
comparison.
Neurohormones
Given the marked haemodynamic changes, we observed
remarkably little neurohormonal perturbation with UCN2
infusion. Despite 19 mmHg falls in MAP, there was no
effect on PRA, aldosterone, or epinephrine, but only a
small initial rise in angiotensin II and elevation in norepinephrine restricted to the higher dose infusion (Figure 1).
In normal humans infused with the same doses of UCN2,
there was a smaller drop in MAP yet significant elevations
in PRA and aldosterone in addition to angiotensin II and norepinephrine.12 This may be partly explained by HF medication in that beta blockade exerts a potent inhibitory
effect upon renin secretion. It is likely that the neurohormonal response to UCN2 differs between normal and HF
states.7,8 In ovine HF, but not in normal sheep, we observed
pronounced suppression of PRA, aldosterone, and epinephrine by UCN2 without elevation of norepinephrine.7
Although this is not seen in the present work, this probably
reflects the stable and relatively mild level of treated HF
with only moderate haemodynamic and neurohormonal
derangement compared with the extreme dysfunction of
our ovine experimental HF model. Nevertheless, given the
magnitude of the drop in MAP (and thus renal perfusion
pressure) observed in our HF patients, a greater renin–
angiotensin system (RAS) activation might be expected.
This suggests relative RAS suppression.
Renal function
Urine volume and urine sodium excretion were slightly
reduced, although creatinine excretion (and presumably
glomerular filtration) were well maintained. Although systemic levels of renin, angiotensin II, and norepinephrine
were not perturbed, we cannot rule out selective intra-renal
activity of these systems as the mechanism underlying these
subtle changes in renal function. Currently no published
data clarify this issue. There is a paucity of information on
the effect of UCN2 on renal cellular activity. The possibility
that the UCNs may have paracrine effects in the kidney is
raised by the known secretion of UCN1 in the kidney.23 The
current findings contrast with the brisk natriuresis observed
in ovine experimental HF, suggesting the natriuretic effect
of UCN is only apparent when acting on a background of
marked activation of the RAS and established avid sodium
retention.
Increases in NTproBNP suggest an increment in cardiomyocyte distortion associated with the increased HR, LVEF, and
CO. This observation was made in this HF group but not previously in normal humans and may be related to established
upregulation of NP synthesis in HF.12
The relatively subtle elevation in ACTH overall contrasts
with the clear-cut stimulation seen with UCN1 in both
normal subjects and in patients with HF.15,24 This presumably reflects the affinity of UCN2 for the peripheral, rather
than central nervous system, receptor subtype.
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internal mammary artery ring smooth muscle via both
endothelium-dependent and -independent mechanisms.21
Falls in CW and SVR extended beyond the period of increased
CO. The effect on calculated CW occurs predominantly postinfusion and reflects longer lasting effects on blood pressure
than on HR (Figures 2 and 3). A moiety that increases CO
without increased CW over sustained intervals may have
therapeutic potential in HF. However, further studies of
the relative importance of vasodilation, positive inotropism,
lusitropism, and chronotropism are warranted, as the
balance between these effects may influence the safety
profile of UCN in treating HF.
The echocardiographic findings are consistent with augmented left ventricular systolic function (with a fall in
LVWMSi indicating increased contractility within viable,
even if diseased, wall segments) and may reflect cardiac
unloading, although, again, direct inotropic effects are
also plausible. The dose-related increases in ejection fraction were substantial (approximately 6 and 15 absolute per
cent for the 25 and 100 mg doses, respectively) despite the
underlying myocardial dysfunction. Transmitral early diastolic flow velocity (E) increased, which may be due to
greater negative pressure induced from more vigorous
recoil after increased contractility, however E/Em (an
index reflecting ventricular filling pressures22) did not
increase. Further comment on possible lusitropism, which
has been noted with UCN2 exposure in both rats and
rabbits,10,17 must be reserved, as direct effects on myocardial relaxation were not measured.
2596
Small rises in plasma adrenomedullin were seen in
response to the two active doses compared with a drop
with placebo. Adrenomedullin is an endothelial product,
and the observed increase may reflect increased endothelial
sheer forces secondary to increased CO and regional blood
flows. Adrenomedullin is a potent vasodilator.25 There has
been no literature as yet on any interaction between adrenomedullin and the UCNs, and whether UCN2 exerts a
direct effect on adrenomedullin release must await further
studies.
Limitations
Conclusion
UCN2 augments CO and reduces vascular resistance in
humans with mild HF. The neutral neurohormonal response
(which falls between the activation observed in normal
humans and the profound suppression observed in severe
experimental HF) despite marked haemodynamic change
suggests relative RAS suppression and that the humoral
response to exogenous UCN2 is dependent on the neurohumoral and haemodynamic milieu into which it is introduced.
Further, natriuresis and hormone suppression may only be
apparent in severe HF when neurohormonal activation is
pronounced and avid sodium retention is established. Experimental and human preclinical studies to date warrant
further investigation of the potentially therapeutic effects
of UCN2 across a spectrum of severity of human HF.
Acknowledgements
This study was financially supported by Neurocrine Biosciences Inc.,
the Health Research Council, the National Heart Foundation of New
Zealand, and the Canterbury Medical Research Foundation. Secretarial assistance was provided by Barbara Griffin.
This study was supported by the Health Research Council of New
Zealand.
Support was also received from Neurocrine Biosciences Inc., San
Diego, CA, USA, which supplied the peptide and funded the
working expenses.
Conflict of interest: none declared.
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The study sample was limited to eight patients with stable
mild HF. The complexity and costs of the protocol with multiple analytes, sampled frequently on three separate
occasions, necessarily limit group size. The results indicate
adequate power for the detection of dose-related changes
in many key haemodynamic variables. Assessment of renal
responses from the current data is limited by trends
towards unmatched baseline (pre-infusion) sodium excretion
between study days. However, the data clearly show that
the profound natriuresis previously seen in animal models
of very severe decompensated HF8 is not present.
The sequential nature of dosing and the flushing response
means imaging was not blinded. Because it is not possible to
fix haemodynamic pre- and after-load in clinical studies of
this type, we cannot precisely define the relative contributions of vasodilatory, inotropic, lusitropic, and chronotropic
actions of UCN to the observed changes in blood pressure, CO,
and CW.
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doi:10.1093/eurheartj/ehm189
Online publish-ahead-of-print 3 June 2007
Shih-Hsien Sung1,2, Shou-Dong Lee1,2, and Hao-Min Cheng1,2*
1
Department of Internal Medicine, Taipei Veterans General Hospital, No. 201, Section 2, Shi-Pai Road, Taipei, Taiwan and
2
School of Medicine, National Yang-Ming University, Taipei, Taiwan
* Corresponding author. Tel: þ886 2 2871 2121, ext. 7511; fax: þ886 2 2875 3580. E-mail address: hmcheng@vghtpe.gov.tw
A 47-year-old woman was hospitalized for the evaluation of
non-exertional left chest pain and left upper arm weakness for 1
year. Chest film taken before admission revealed an apparently
normal-sized heart (Panel A). A mass was uncovered unexpectedly
by transoesophageal echocardiography (Panels B and C, arrows).
Then the patient received open heart surgery during admission. A
foreign body, a bamboo chopstick, was noticed after the chest wall
was opened (Panel D). An intraparenchymal fistula was created by
the foreign body with adhesion to apical lung and left hilum just
above the superior pulmonary vein. The foreign body also penetrated into the pericardium over the auricle of the left atrium.
The foreign body was removed (Panel E) and fistulectomy was
performed. The patient recovered uneventfully. Pathology of the
excised left atrial mass demonstrated fibrocalcified nodule (Panel
F), suggesting chronic tissue reaction to the foreign body.
Re-examining the chest film, a band-shaped mass over the left
lung field was noted (Panel A, arrow). Tracing back her history,
the patient recalled a fight when she was heavily drunk 10 years
before and the chopstick was probably jabbed into her left upper
back at that time.
& The European Society of Cardiology 2007. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org
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An unusual cause of left atrial mass