Combined antihypertensive and cardioprotective effects of nebivolol and hydrochlorothiazide in spontaneous hypertensive rats.

Abstract

The antihypertensive and cardioprotective effects of the combination of nebivolol (NEB) and hydrochlorothiazide (HCTZ) in spontaneously hypertensive rats (SHR) were investigated. SHR and age-matched Wistar-Kyoto normotensive rats were randomly assigned to one of six groups: SHR treated with NEB (1 mg/kg/day, intragastric); SHR treated with HCTZ (5 mg/kg/day, intragastric); SHR treated with NEB plus HCTZ (1 + 2.5 mg/kg/day); SHR treated with NEB plus HCTZ (1 + 5 mg/kg/day), along with a SHR and a WKY control group. The effects of NEB and HCTZ on clinical chemistry parameters and on cardiac function and structure were evaluated. NEB and HCTZ in combination had synergistic antihypertensive effects and significantly reduced heart rate and blood pressure compared with monotherapy with either agent. These effects were independent of water intake, urine output and electrolyte excretion. NEB plus HCTZ was associated with reduced oxidative stress in terms of glutathione availability, lower angiotensin I levels as index of plasma renin activity and reduced clearance of urinary sodium compared with HCTZ alone. Cardiac morphometric data and antioxidant parameters indicate that NEB may influence cardiac structure by reducing hypertrophy and by enhancing the availability of endothelial nitric oxide - a unique characteristic of NEB. The authors suggest that a combination of NEB and HCTZ for the treatment of hypertension may be useful for the synergistic characteristics of both drugs.

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Future Cardiology
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Future Cardiol. (2011) 7(6), 757–763
The combination of a b-blocker and a thiazide
is well established in the treatment of hyper-
tension [1]. The combination has more marked
antihypertensive effects and importantly
reduces the metabolic side effects observed
with first- and second-generation b-blockers
and higher doses of thiazides [2]. b-blockers
in general, suppress the production of renin,
thus reducing the formation of angiotensin II
(Ang II), one of the most potent hypertensive
factors. The upregulation of renin that results
from diuretic administration can be normal-
ized with concomitant administration of a
b-blocker [3]. Diuretics and b-blockers reduce
high blood pressure (BP) by different biological
pathways: the former reduces fluid pressure in
the body by increasing the diuresis of urine, the
latter mainly reduces cardiac work load. The
third-generation b-blocker nebivolol (NEB), in
addition to these effects also has the ability to
reduce peripheral resistance by its distinctive
effects on nitric oxide (NO) release from endo-
thelial cells [4]. The NEB effect on endothelial
NO synthase (eNOS) uncoupling can be fur-
ther enhanced by the antioxidant properties of
hydrochlorothiazide (HCTZ) that is able to
reduce reactive oxygen species in experimental
hypertension models [5].
The aim of the present study was to investi-
gate the interaction between NEB and HCTZ
on cardiovascular and renal function in spon-
taneous hypertensive rats (SHR), in order to
get a better understanding of the additive/syn-
ergistic antihypertensive and cardioprotective
effects when given in combination.
Materials & methods
Experimental design
Rats were housed in a limited access rodent
facility under standard conditions of tem-
perature (22 ± 2°C) and relative humidity
(55 ± 15%) and 12-h light–dark cycle. Food
and water were available ad libitum. A 2-week
acclimatization period was allowed before the
start of treatment. Experiments were carried
out in accordance with European and national
Combined antihypertensive and
cardioprotective effects of
nebivolol and hydrochlorothiazide
in spontaneous hypertensive rats
Giuseppe Sacco1, Stefano Evangelista†2, Stefano Manzini2, Massimo Parlani1
& Mario Bigioni1
1Menarini Ricerche SpA, Pharmacology Department, Via Tito Speri 10, 00040 Pomezia, Roma, Italy
2Menarini Ricerche SpA, Preclinical Development Department, Via Sette Santi 1, 50131 Firenze, Italy
†Author for correspondence: Tel.: +39 055 568 0519 n Fax: +39 055 568 0419
n sevangelista@menarini-ricerche.it
The antihypertensive and cardioprotective effects of the combination of nebivolol
(NEB) and hydrochlorothiazide (HCTZ) in spontaneously hypertensive rats (SHR)
were investigated. SHR and age-matched Wistar-Kyoto normotensive rats were
randomly assigned to one of six groups: SHR treated with NEB (1 mg/kg/day,
intragastric); SHR treated with HCTZ (5 mg/kg/day, intragastric); SHR treated with
NEB plus HCTZ (1 + 2.5 mg/kg/day); SHR treated with NEB plus HCTZ (1 + 5 mg/kg/
day), along with a SHR and a WKY control group. The effects of NEB and HCTZ on
clinical chemistry parameters and on cardiac function and structure were
evaluated. NEB and HCTZ in combination had synergistic antihypertensive effects
and significantly reduced heart rate and blood pressure compared with
monotherapy with either agent. These effects were independent of water intake,
urine output and electrolyte excretion. NEB plus HCTZ was associated with
reduced oxidative stress in terms of glutathione availability, lower angiotensin I
levels as index of plasma renin activity and reduced clearance of urinary sodium
compared with HCTZ alone. Cardiac morphometric data and antioxidant
parameters indicate that NEB may influence cardiac structure by reducing
hypertrophy and by enhancing the availability of endothelial nitric oxide – a
unique characteristic of NEB. The authors suggest that a combination of NEB and
HCTZ for the treatment of hypertension may be useful for the synergistic
characteristics of both drugs.
Keywords
n b-blocker n diuretic
n hydrochlorothiazide
n nebivolol n nitric oxide
n spontaneous
hypertensive rats
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guidelines and the study was approved by the
local ethics committee.
A total of 48 male rats (40 SHR and 8 Wistar-
Kyoto [WKY]), 7–8 weeks old (180–200 g),
from Harlan s.r.l., Udine, Italy, were randomly
divided into six groups: SHR treated with
NEB (1 mg/kg/day, intragastric); SHR treated
with HCTZ (5 mg/kg/day, intragastric); SHR
treated with NEB plus HCTZ (1 + 2.5 mg/
kg/day); SHR treated with NEB plus HCTZ
(1 + 5 mg/kg/day), a SHR control group and
a WKY control group. Doses were selected on
the basis of previous experience with SHR [6]
and the ratio between the two components was
selected according to the approved dosages for
NEB (Nebilet Plus®) [7]. Active treatments,
NEB (Berlin Chemie, Menarini Group, Berlin,
Germany) and HCTZ (Sigma-Aldrich, Milan,
Italy), both diluted in water, were administered
orally intragastric in a volume of 10 ml/kg once
a day for 4 weeks. Control animals received
the vehicle alone (water) at the same dose vol-
ume. All animals were dosed until the day
before necropsy.
Measurements
Rats were weighed on allocation to treatment, on
the day treatment started, thereafter at weekly
intervals and just before necropsy. Mean arte-
rial pressure (MAP) and heart rate (HR) were
recorded pretreatment and on days 3, 7, 14 and
28 of the study in conscious rats with an auto-
mated single channel volume pressure record-
ing tail-cuff system (Kent Scientific, USA).
Measurements were performed in a room at 25°C
at the same time of day to avoid the influence
of the circadian rhythm. Each value was deter-
mined as the mean of four consecutive measure-
ments that did not differ from one another by
more than 10 mmHg.
Mean daily water consumption per rat was
also calculated. Kidneys, heart and left ventricle
weight were determined for all animals com-
pleting the scheduled test period and the ratio
of individual organ weights to body weight
was calculated.
Blood & urine measurements
Measurements performed on blood and urine
samples (taken on day 29 from the retro-orbital
sinus in heparinized tubes under isofluorane
anesthesia and by metabolic cage, respectively)
were: blood urea, creatinine, sodium, potassium,
Ang I (for this parameter due to low individual
levels, plasma was pooled), glutathione and for
urine–volume, specific gravity, pH, glutathione
and clearance of creatinine, potassium and
sodium. Apart from Ang I determination as
index of plasma renin activity, for which an
HPLC-electrospray-tandem mass spectrometry-
assay [8] was used, other analyses were performed
using standard assays (Roche Diagnostics,
Milan, Italy) and measured by System IL 943
(flame photometer).
Statistical analyses
Data were expressed as mean ± standard error
mean and statistical analyses were performed
by means of ana lysis of variance (ANOVA) fol-
lowed by Dunnett’s test for multiple comparison.
Difference amongst groups were considered at
two levels of significance: p < 0.05 or <0.01.
Results
Hemodynamic effects
The mean arterial pressure (MAP) of WKY
averaged 140 mmHg during the study while
the initial higher BP of SHR progressively
increased up to 27.6 mmHg over the basal
value (Table 1). Treatment with NEB alone sig-
nificantly reduced MAP starting from day 3 of
treatment as compared with SHR, while treat-
ment with HCTZ alone reduced MAP only
after 2 weeks of treatment. Both dosage com-
binations of NEB and HCTZ reduced MAP to
a greater extent compared with either therapy
given alone (Table 1). At the end of treatment,
both systolic BP pressure (SBP) and diastolic BP
(DBP) were markedly reduced by combination
therapy, but the effect was particularly evident
when NEB was administered in combination
with the higher dose of HCTZ (see Figure 1 for
variations from baseline).
Heart rate in SHR was always significantly
higher than that in WKY (Table 1). NEB alone
progressively decreased HR during the 4-week
period while HCTZ alone had no effect on
this parameter (Table 1). Both combinations
reduced HR significantly in WKY compared
with SHR and importantly the combination
NEB + HCTZ (1 + 5 mg/kg/day) had a notable
bradycardic effect on days 3 and 7 of treatment.
Effect on renal excretory functions &
clinical chemistry parameters
Water intake and urine output were not sig-
nificantly different between WKY and SHR
but water intake was significantly lower in all
groups treated with HCTZ and urine output
was reduced by 42% after treatment with the
NEB + HCTZ combination (1 + 5 mg/kg/day)
(Table 2). Likewise, urine pH was significantly
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reduced (more acidic), compared with SHR, in
the groups treated with HCTZ 5 mg/kg/day
(Table 2). Clearance of urinary sodium was
increased in SHR as compared with WKY and
this parameter significantly decreased in groups
treated with HCTZ (Table 2). Urinary clearance
of potassium and creatinine remained constant
in all groups.
Levels of sodium, potassium and creatinine
in the plasma were not different amongst the
groups with the exception of slight changes in
sodium plasma levels observed in groups treated
with the combination (Table 2). Plasma urea was
increased in all SHR (control and treated)
groups (Table 2). The ratio of plasma glutathione
(free/total) was increased in the SHR plasma,
as compared with WKY, and decreased in the
NEB, HCTZ and combination groups (Table 2).
In WKY and SHR Ang I plasma levels were
below the limit of detection, whilst a remark-
able amount was measured in SHR rats treated
with HCTZ (Table 2). Interestingly enough this
HCTZ-induced Ang I increase was largely
antagonized by the concomitant administra-
tion of NEB, that per se has negligible effects on
Ang I level (Table 2).
Table 1. Effect of nebivolol and hydrochlorothiazide alone and their combinations on mean arterial pressure
and heart rate in spontaneous hypertensive rats during a 4-week period of treatment.
PredoseDay 3Day 7 Day 14Day 28
Mean arterial pressure
WKY
SHR
NEB 1 mg/kg/day
HCTZ 5 mg/kg/day
NEB 1 mg/kg/day + HCTZ 2.5 mg/kg/day 160.6 ± 2.1†
NEB 1 mg/kg/day + HCTZ 5 mg/kg/day
Heart rate
WKY
SHR
NEB 1 mg/kg/day
HCTZ 5 mg/kg/day
NEB 1 mg/kg/day + HCTZ 2.5 mg/kg/day 384.4 ± 10.0†
NEB 1 mg/kg/day + HCTZ 5 mg/kg/day
128.9 ± 4.7
162.1 ± 2.7†
164.4 ± 5.0†
167.8 ± 1.5†
139.3 ± 5.8
172.5 ± 2.8†
158.8 ± 3.8†‡
177.5 ± 5.0†
157.0 ± 4.0†‡
160.7 ± 4.5†‡
141.7 ± 4.0
185.2 ± 3.8†
164.0 ± 2.9†‡
175.7 ± 3.6†
155.0 ± 4.1†‡
148.6 ± 4.5†‡
140.6 ± 5.9
182.3 ± 3.0†
161.2 ± 5.2†‡
166.3 ± 2.4†‡
151.9 ± 5.1†‡
164.6 ± 5.6†‡
135.9 ± 3.8
189.7 ± 3.2†
168.4 ± 8.5†‡
176.5 ± 5.0†‡
164.7 ± 4.5†‡
160.2 ± 2.7†‡
168.1 ± 2.7†
350.6 ± 9.0
399.0 ± 9.0†
403.6 ± 10.3†
393.0 ± 12.1†
371.0 ± 13.1
391.5 ± 14.9
379.7 ± 3.8†
424.3 ± 8.3†
391.7 ± 6.3
358.6 ± 10.4†‡
380.0 ± 15.4
439.5 ± 7.9†
368.1 ± 6.3†‡
447.7 ± 14.9†
387.7 ± 7.5†‡
335.3 ± 11.0†‡
353.2 ± 11.8
440.4 ± 12.3†
375.7 ± 13.3†‡
400.9 ± 8.7†
380.3 ± 6.7†‡
382.4 ± 9.3†‡
365.8 ± 9.0
417.8 ± 7.3†
360.7 ± 11.7†‡
429.6 ± 17.3†
383.5 ± 5.9‡
369.0 ± 6.4‡
399.3 ± 11.0†
†p <0.05 versus WKY group; ‡p <0.05 or 0.01 versus SHR group. n = 6–7 for each group.
HCTZ: Hydrochlorothiazide; NEB: Nebivolol; SHR: Spontaneous hypertensive rats; WKY: Winstar–Kyoto.
Variation (mmHg)
40
30
20
10
0
-10
-20
DBPSBP
WKY (n = 7)
SHR (n = 7)
NEB 1 mg/kg/day (n = 6)
HCTZ 5 mg/kg/day (n = 7)
NEB 1 mg/kg/day +
HCTZ 2.5 mg/kg/day (n = 7)
NEB 1 mg/kg/day +
HCTZ 5 mg/kg/day (n = 6)
Figure 1. Effect of hydrochlorothiazide and nebivolol alone and in combination on
variation of diastolic and systolic blood pressure in SHR after a 4-week period of treatment
from baseline values. All values were significantly (p < 0.05) different from those of SHR group.
DBP: Diastolic blood pressure; HCTZ: Hydrochlorothiazide; NEB: Nebivolol; SBP: Systolic blood
pressure; SHR: Spontaneous hypertensive rats; WKY: Winstar–Kyoto.
Combined antihypertensive & cardioprotective effects of nebivolol & hydrochlorothiazide
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Effect on morphometric parameters of
heart & kidney
There was a highly significant increase in rela-
tive heart and left ventricular weight, but not in
kidney weight, in SHR compared with WKY
rats (Table 3). Treatment with NEB alone and
its combination with HCTZ partially inhib-
ited this increase reducing the relative weight of
the heart and the left ventricular (Table 3). Drug
treatment had no effect on relative kidney and
absolute body weight. A trend of lower body
weight (in the range of 10–12%) resulted in all
SHR groups as compared with WKY except for
groups treated with the combination (Table 3).
Discussion
Our findings show that in SHR, NEB was more
effective than HCTZ in reducing BP. Furthermore,
the combination of NEB and HCTZ at low doses
is highly effective in reducing hypertension. At the
end of the 4-week period, treatment with NEB
plus HCTZ reduced BP by 30 mmHg compared
with matched SHR. The additive effect of the
combination with NEB and HCTZ is reinforced
by the distinctive characteristics of this third-
generation vasodilator b-blocker [9,10], in its abil-
ity to release NO from endothelial cells. In SHR
the NO pathway is subjected to the mechanism
of eNOS uncoupling leading to endothelial dys-
function [11,12] and NEB might counteract this
mechanism and reduce peripheral resistance as
shown in other studies [4,6]. Mason et al. demon-
strated that the preferential formation of highly
reactive oxidative products such as peroxynitrites
and the reduced bioavailability of NO, evident in
endothelial cells of SHR, is restored with NEB
treatment [11]. In this context, it is interesting to
note that HCTZ has also been recently shown to
possess antioxidant properties in a model of reno-
vascular hypertension and therefore it can act in
synergy with NEB in the eNOS uncoupling [5].
Furthermore, in our experiment, the combina-
tion of NEB plus HCTZ restored the ratio of free
over total circulating glutathione – an index of
oxidative stress that is increased in SHR [13].
Treatment with HCTZ alone is slightly active
and the combination with NEB increased the
hypotensive effect. It appears that the antihy-
pertensive effect in SHR of HCTZ is not only
linked to a diuretic effect as confirmed in other
studies [14,15]. It is well known that, acting at
the cortical diluting tubular segment, thiazide
diuretics, particularly at high dosages, induce
negative changes in sodium and fluid balance
while decreasing circulating blood volume and
cardiac output [16]. Initially, peripheral vascular
Table 2. Effect of nebivolol and hydrochlorothiazide alone and their combinations on fluid and clinical
chemistry parameters of spontaneous hypertensive rats.
WKY SHR NEB
1 mg/kg/day
HCTZ
5 mg/kg/day
NEB
1 mg/kg/day +
HCTZ
2.5 mg/kg/day
23.6 ± 0.3§
8.7 ± 2.9
1.025 ± 0.007
6.9 ± 0.35
NEB
1 mg/kg/day +
HCTZ
5 mg/kg/day
23.6 ± 0.4§
4.9 ± 1.6
1.035 ± 0.007§
6.5 ± 0.00¶
Water intake (ml)
Urine volume (ml)
Urine specific gravity
Urine pH
Clearance of urinary
sodium (nmol/h)
Clearance of urinary
potassium (nmol/h)
Clearance of urinary
creatinine (mgl/h)
Plasma sodium (mmol/l)
Plasma potassium
(mmol/l)
Plasma creatinine (mg/dl) 0.340 ± 0.056
Plasma urea (mg/dl)
Plasma glutathione
(free/total)
Plasma angiotensin I
(ng/ml)
26.8 ± 1.0
8.6 ± 3.2
1.021 ± 0.005
6.9 ± 0.35
0.0123 ± 0.0043 0.0224 ± 0.0034†0.0152 ± 0.0037 0.0066 ± 0.0032¶0.0076 ± 0.0033¶0.0030 ± 0.0013¶
27.7 ± 0.4
8.1 ± 3.9
1.025 ± 0.008
7.3 ± 0.39
25.6 ± 0.4
6.5 ± 3.6
1.023 ± 0.008
6.9 ± 0.20
23.6 ± 0.9§
8.5 ± 2.8
1.026 ± 0.005
6.6 ± 0.24¶
0.0316 ± 0.0104 0.0361 ± 0.0086 0.0380 ± 0.0062 0.0335 ± 0.00440.0329 ± 0.00830.0319 ± 0.0038
0.3197 ± 0.0702 0.2734 ± 0.0423 0.2673 ± 0.0282 0.2983 ± 0.03210.2987 ± 0.0402 0.2840 ± 0.0279
147.9 ± 1.2
3.80 ± 0.21
146.3 ± 1.5
3.87 ± 0.44
148.6 ± 1.5
4.01 ± 0.46
147.5 ± 1.2
3.47 ± 0.18
149.7 ± 0.9
3.71 ± 0.29
140.5 ± 1.2¶
3.44 ± 0.24
0.274 ± 0.030
50.6 ± 9.5‡
60.4 ± 6.6‡
0.217 ± 0.061
57.9 ± 3.4‡
51.9 ± 5.6
0.279 ± 0.036
49.6 ± 3.9‡
44.6 ± 7.1
0.294 ± 0.029
49.8 ± 2.6‡
49.1 ± 5.0
0.348 ± 0.090
53.9 ± 6.4‡
40.4 ± 8.8§
34.1 ± 5.9
34.6 ± 2.4
bldbld0.351.50.9 0.4
† or ‡p <0.05 or 0.01 versus WKY group; § or ¶p <0.05 or 0.01 versus SHR group. n = 6–7 for each group.
bld: Below limit of detection of 0.29 ng/ml; HCTZ: Hydrochlorothiazide; NEB: Nebivolol; SHR: Spontaneous hypertensive rats; WKY: Winstar–Kyoto.
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resistance increases to partially compensate for
the reduction in cardiac output and arterial
pressure. In the long term both plasma volume
and cardiac output are partly restored, keeping
BP low by decreasing peripheral resistance [17].
We also observed that the effects of low dose
HCTZ on BP became evident only after 2 weeks
of treatment. We also found that groups treated
with HCTZ for 4 weeks showed reduced water
intake, lower values of urinary pH and s pecific
gravity and unchanged urinary output.
Another noteworthy finding is the effect of the
combination on Ang I, an index of plasma renin
activity. Diuretics are known to stimulate the
renin–angiotensin system indirectly via negative
sodium balance and increasing renin and Ang I
and II. In SHR (a low renin hypertensive model [18]
which differs from other experimental models
where the renin is markedly enhanced [19]), we
observed an increase of Ang I following HCTZ
treatment and this increase was normalized after
the concomitant administration of NEB. b-recep-
tor blockade decreases renin expression and secre-
tion [20] and in clinical trials it has been observed
that upregulation of the renin–angiotensin system
induced by treatment with angiotensin convert-
ing enzyme inhibitors, diuretics or both can be
prevented by the concomitant administration of
b-blockers [3]. NEB has recently been shown to
normalize renin levels, increased by an 8% salt
diet in SHR [21]. In addition to its vasodilating
properties, NEB is known to be one of the most
selective b-1 adrenoceptor blockers [12,22] and we
observed marked bradycardic effects in all groups
treated with NEB. Reduction of heart rate con-
tributes to reduction in cardiac work load that is
a typical class effect. This bradycardic effect is
maintained (or even improved in a short term)
when NEB is combined with HCTZ.
The increased blood urea observed in all SHR
groups indicate that in these animals, renal func-
tion was impaired and none of the treatments
ameliorated the situation which also occured
in the presence of a significant reduction in BP.
Likewise, kidney weight was not affected by
treatment in SHR. Possibly kidney damage was
produced in the development of the spontaneous
hypertension of these animals and in this case
the short period of treatment with the drugs were
not sufficient to block or reverse renal impair-
ment. In the presence of this impairment of the
kidney, we have observed a significant reduction
of blood and urine sodium in the group treated
with the combination but this effect was mainly
due to the diuretic.
Importantly, both drugs alone or in combina-
tion reduced cardiac morphometric parameters
(heart and left ventricle weight) indicating a
beneficial effect of BP reduction. In particular,
the groups treated with NEB + HCTZ had a
greater reduction of these structural parameters
compared with SHR, confirming the effect of
the drug(s) on the cardiac work load and the
concomitant reduction of peripheral resistance.
Likewise, Guerrero et al. found that in SHR
monotherapy with NEB, administered at a dose
eight-times higher than that used in the present
experiments and for a longer period of time (9
weeks), decreased the cardiac hypertrophy such
as collagen deposition and medial thickness
along with an improved endothelium vasodila-
tion [6]. We obtained similar reductions in BP by
adding a low-dose thiazide (2.5–5 mg/kg/day)
to a low dose NEB (1 mg/kg/day) and we
observed that the cardiac morphometric param-
eters were significantly reduced. The develop-
ment of fibrosis that follows a sustained period
of hypertension, such as that observed in SHR,
Table 3. Effect of nebivolol and hydrochlorothiazide alone and their combinations on morphometric parameters
of spontaneous hypertensive rats.
Relative
organ
weight
Heart
weight (g)
Left
ventricular
weight (g)
Kidney
weight (g)
Body weight
(g, absolute)
WKYSHRNEB
1 mg/kg/day
HCTZ
5 mg/kg/day
NEB 1 mg/kg/day
+ HCTZ
2.5 mg/kg/day
0.381 ± 0.006†
NEB 1 mg/kg/day
+ HCTZ
5 mg/kg/day
0.374 ± 0.008†‡
0.338 ± 0.007 0.399 ± 0.008†0.375 ± 0.006†‡
0.386 ± 0.003†
0.240 ± 0.004 0.291 ± 0.006†0.267 ± 0.005†§
0.280 ± 0.004†
0.277 ± 0.005†
0.282 ± 0.004†
0.659 ± 0.009 0.646 ± 0.019 0.628 ± 0.0100.642 ± 0.0080.636 ± 0.014 0.655 ± 0.007
286.8 ± 6.0 253.9 ± 7.1257.9 ± 6.1254.2 ± 7.9 269.3 ± 8.7283.6 ± 7.6
†p <0.05 or 0.01 versus WKY group; ‡ or §p <0.05 or 0.01 versus SHR group. n = 6–7 for each group.
HCTZ: Hydrochlorothiazide; NEB: Nebivolol; SHR: Spontaneous hypertensive rats; WKY: Winstar–Kyoto.
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Financial & competing interests disclosure
All authors are employees of Menarini Spa, part of the
Menarini group, European marketing authorization
holder of the combination nebivolol and hydrochloro-
thiazide. The authors have no other relevant affilia-
tions or financial involvement with any organization
or entity with a financial interest in or financial conflict
with the subject matter or materials discussed in the
manuscript apart from those disclosed.
No writing assistance was utilized in the production
of this manuscript.
Executive summary
n?Nebivolol (a third generation b-blocker endowed with peculiar characteristic to release nitric oxide from endothelium) and
hydrochlorothiazide in combination had a remarkable effect on blood pressure reduction and heart rate control in rat
experimental hypertension.
n?The nebivolol and hydrochlorothiazide combination exerted greater beneficial cardiovascular effects than the monotherapies.
n?The antihypertensive effects induced by the combination were associated with reduction of oxidative stress and enhanced clearence of
urinary sodium.
n?The increase of angiotensin I (an index of plasma renin activity) plasma levels induced by the diuretic was normalized by the
concomitant administration of the b-blocker.
n?Cardiac morphometric parameters worsened by the prolonged hypertension were ameliorated by single or combined administration of
nebivolol and hydrochlorothiazide.
n?The favorable pattern of cardiovascular effects with the combination nebivolol plus hydrochlorothiazide might concurr to the long-term
cardiovascular protection during antihypertensive treatment and might reduce the risk factors due to prolonged hypertension.
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can be prevented by the vasodilating and hypo-
tensive properties exerted by the combination
of NEB + HCTZ.
Conclusion
The combination of the thiazide diuretic HCTZ
plus NEB generates a series of beneficial and
additive effects in experimental hypertension due
to the synergistic c haracteristics of both drugs.
Future perspective
Antihypertensive agents such as b-blockers, angi-
otensin-converting enzyme inhibitors, sartans and
diuretics are usually indicated for mild-to-moder-
ate hypertension while combination of them are
used in severe hypertensive patients or in those
nonresponders to the monotherapy. The trend of
today is to treat this pathology with several agents
in order to associate the benefit of one class to
another. The aging of the western population and
the concomitant increase of hypertensive patients
with associated pathologies reinforces the need of
multi-treatment. Experimental findings showed
that nebivolol, a third generation b-blocker
endowed with the peculiar characteristic to release
nitric oxide from endothelium and the diuretic
hydrochlorthiazide showed a synergistic activity
able to concurr to the long-term cardiovascular
protection. Such combinations potentially able
to not only reduce the blood pressure but also
the cardiovascular risk factors are probably the
mainstay of the future therapy for hypertension.
Acknowledgements
The authors would like to thank ContentEdNet for
English language assistance, Donatella Bemporad, for
her advice and suggestions and Alessandro Pineda and
Sabrina Cecili for their technical support.
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Combined antihypertensive & cardioprotective effects of nebivolol & hydrochlorothiazide
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