ArticlePDF Available

Abstract and Figures

Background: Obesity is a chronic low-grade inflammation condition related to cardiac disorders. However, the mechanism responsible for obesity-related cardiac inflammation is unclear. The toll-like receptor 4 (TLR-4) belongs to a receptor of the transmembrane family responsible for the immune response whose activation stimulates the production of proinflammatory cytokines. Objective: To test whether the activation of the TLR-4 receptor participates in the obesity cardiomyopathy process, due to cytokine production through NF-ĸB activation. Methods: Male Wistar rats were randomized into two groups: the control group (C, n= 8 animals) that received standard diet/water and the obese group (OB, n= 8 animals) that were fed a high sugar-fat diet and water plus 25% of sucrose for 30 weeks. Nutritional analysis: body weight, adiposity index, food, water, and caloric intake. Obesity-related disorders analysis: plasma glucose, uric acid and triglycerides, HOMA-IR, systolic blood pressure, TNF-α in adipose tissue. Cardiac analysis included: TLR-4 and NF-ĸB protein expression, TNF-α and IL-6 levels. Comparison by unpaired Student's t-test or Mann- Whitney test with a p-value < 0.05 as statistically significant. Results: The OB group showed obesity, high glucose, triglycerides, uric acid, HOMA, systolic blood pressure, and TNF-α in adipose tissue. OB group presented cardiac remodeling and diastolic dysfunction. TLR-4 and NF-ĸB expression and cytokine levels were higher in OB. Conclusion: Our findings conclude that, in an obesogenic condition, the inflammation derived from cardiac TLR-4 activation can be a mechanism able to lead to remodeling and cardiac dysfunction.
Content may be subject to copyright.
Arq Bras Cardiol. 2021; 117(1):91-99 91
Original Article
Relationship between Innate Immune Response Toll-Like
Receptor 4 (TLR-4) and the Pathophysiological Process of Obesity
Cardiomyopathy
Pedro Henrique Rizzi Alves,1 Artur Junio Togneri Ferron,1 Mariane Róvero Costa,1 Fabiana Kurokawa Hasimoto,1
Cristina Schmitt Gregolin,1,2 Jéssica Leite Garcia,1 Dijon Henrique Salomé de Campos,1 Antônio Carlos
Cicogna,1 Letícia de Mattei,1 Fernando Moreto,1 Silméia Garcia Zanati Bazan,1 Fabiane Valentini Francisqueti-
Ferron,1 Camila Renata Corrêa1
Universidade Estadual Paulista Júlio de Mesquita Filho Câmpus de Botucatu Faculdade de Medicina,1 Botucatu, SP - Brazil
Universidade Federal de Mato Grosso,2 Sinop, MT – Brazil
Mailing Address: Fabiane Valentini Francisqueti-Ferron
Universidade Estadual Paulista, Faculdade de Medicina - Avenida Prof Mario
Rubens Guimarães Montenegro, s/n. Postal code 18618-687,
Botucatu, SP – Brazil
E-mail: fabiane_vf@yahoo.com.br
Manuscript received November 14, 2019, revised manuscript May 04, 2020,
accepted June 16, 2020
DOI: https://doi.org/10.36660/abc.20190788
Abstract
Background: Obesity is a chronic low-grade inflammation condition related to cardiac disorders. However, the
mechanism responsible for obesity-related cardiac inflammation is unclear. The toll-like receptor 4 (TLR-4) belongs to a
receptor of the transmembrane family responsible for the immune response whose activation stimulates the production
of proinflammatory cytokines.
Objective: To test whether the activation of the TLR-4 receptor participates in the obesity cardiomyopathy process, due
to cytokine production through NF-ĸB activation.
Methods: Male Wistar rats were randomized into two groups: the control group (C, n= 8 animals) that received
standard diet/water and the obese group (OB, n= 8 animals) that were fed a high sugar-fat diet and water plus 25% of
sucrose for 30 weeks. Nutritional analysis: body weight, adiposity index, food, water, and caloric intake. Obesity-related
disorders analysis: plasma glucose, uric acid and triglycerides, HOMA-IR, systolic blood pressure, TNF-α in adipose
tissue. Cardiac analysis included: TLR-4 and NF-ĸB protein expression, TNF-α and IL-6 levels. Comparison by unpaired
Student’s t-test or Mann- Whitney test with a p-value < 0.05 as statistically significant.
Results: The OB group showed obesity, high glucose, triglycerides, uric acid, HOMA, systolic blood pressure, and TNF-α
in adipose tissue. OB group presented cardiac remodeling and diastolic dysfunction. TLR-4 and NF-ĸB expression and
cytokine levels were higher in OB.
Conclusion: Our findings conclude that, in an obesogenic condition, the inflammation derived from cardiac TLR-4
activation can be a mechanism able to lead to remodeling and cardiac dysfunction.
Keywords: Cardiovascular Diseases/physiopathology; Obesity; Inflammation; Cytokines; Adipocytes; Fatty Acid
synthases; Nutrional Assessment.
Introduction
Obesity, defined as an excessive body fat accumulation that
may impair an individual’s health,1 is currently considered the
most important nutritional disorder in both developed and
underdeveloped countries.2 Estimates show that in 2025 at
least 18% of the adult population will be obese, a worrying
condition since it can lead to several comorbidities, including
cardiovascular diseases.3,4
One of the main causes responsible for the obesity epidemic
is the excessive consumption of hypercaloric diets, which are
rich in saturated fat and refined sugars, associated with a
sedentary health style.5,6 This modern lifestyle leads to adipose
tissue hypertrophy that triggers, initially, a local inflammatory
process, which may later affect and compromise the function
of other organs, such as the heart.7 This inflammation of
metabolic origin results in the synthesis of the proinflammatory
cytokines led by different pathways, among them: adipose
tissue lipolysis,8 adipocytes hypertrophy,9 fatty acids from
the diet,10 and intestinal lipopolysaccharides (LPS) due to
dysbiosis.11 Within this context, free fatty acids and LPS are
the main components involved in the inflammatory response,
acting as Damage-Associated Molecular Patterns (DAMPs) and
Pathogen-associated Molecular Patterns (PAMPs), respectively,
which are recognized by some receptors, especially the Toll-
Like Receptor 4 (TLR-4).12
Arq Bras Cardiol. 2021; 117(1):91-99
92
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
TLR-4 belongs to a family of receptors usually expressed
in cells of the innate immune system, such as macrophages,
neutrophils, and lymphocytes, and exerts an important role
to detect and recognize pathogens leading to the innate13
and acquired14 immune response activation. This receptor
is responsible for the activation of the nuclear factor kappa
B (NF-ĸB) with consequent synthesis of proinflammatory
cytokines involved in the pathophysiology of several diseases,
including heart diseases.15
However, the literature reports that the TLR-4 receptor is
not expressed only in immune system cells. Cardiomyocytes
also express this receptor and its activation, especially against
infectious cardiac pathogens, contributes to the myocardial
dysfunction process.16–18 Although the involvement of the
immune system in the development of cardiac pathologic
hypertrophy is well established,14,19,20 the TLR-4 pathway
participation in the development and progression of obesity-
related cardiac remodeling has not yet been clarified.21
Considering the lack of studies regarding this topic, the aim
of this study was to test the hypothesis that the TLR-4 receptor
activation participates in the obesity cardiomyopathy process,
due to production of cytokine through the NF-ĸB activation.
Material and Methods
Experimental Protocol
Male Wistar rats (n=16), 21 days of age, were obtained
from Universidade Estadual Paulista (UNESP). Sample size
was calculated by using SigmaStat for Windows, version 3.5
(Systat Software Inc., San Jose, CA, USA), considering the
expected difference mean of 2.0, expected standard deviation
of 1.0, test power of 90%, and α of 0.05. This calculation
considered the adiposity index of previous studies published
by our group.22–24 The animals were randomly divided into
two experimental groups: the control group (C, n= 8 animals)
that received standard diet/water and the obese group (OB,
n= 8 animals) that received high sugar-fat (HSF) diet and
water plus 25% of sucrose for 30 weeks. The diet model is a
well-established model to induce obesity previously published
by our research group.25 The HSF diet contained soybean
meal, sorghum, soybean peel, dextrin, sucrose, fructose, lard,
vitamins, and minerals, plus 25% sucrose in drinking water.
The control diet contained soybean meal, sorghum, soybean
peel, dextrin, soy oil, vitamins, and minerals.
Food and water were offered ad libitum and the animals
were kept in individual cages, in an environment with
controlled temperature (24 ± 2°C), humidity (55 ± 5%),
and light-dark cycle (12-12h). The study protocol (CEUA
1265/2018) was approved by the Ethics Committee on Animal
Experimentation of the Botucatu School of Medicine, UNESP,
São Paulo, Brazil, and followed the recommendations from
the Guide for the Care and Use of Experimental Animals.26
At the end of 30 weeks, the animals were fasted for 8h, then
euthanized and the material was collected for analysis.
Nutritional Evaluation
Food and water consumption were evaluated daily. Caloric
intake was determined by multiplying the energy value of
each diet (g × Kcal) by daily food intake. For the OB group,
caloric intake also included water calories (0.25 × 4 × mL
consumed). The animals’ body weight was measured weekly.
After euthanasia, visceral fat (VAT), epididymal fat (EAT), and
retroperitoneal fat (RAT) were collected and used to calculate
the adiposity index (AI) by the formula: [(VAT + EAT + RAT)
/ ANIMAL WEIGHT] x100.
Obesity-related disorders analysis
Plasma glucose and triglycerides, (BioClin, Quibasa
Química Básica Ltda., Belo Horizonte, Minas Gerais, Brazil)
were measured by colorimetric-enzymatic method in an
automatic enzymatic analyzer system (Chemistry Analyzer
BS-200, MindrayMedical International Limited, Shenzhen,
China). Insulin (EMD Millipore Corporation, Billerica, MA,
USA) was analyzed in plasma by ELISA using a commercial kit.
The reading was performed by Spectra Max 190 microplate
spectrophotometer (Molecular Devices®, Sunnyvale, CA, USA).
The Homeostatic Model Assessment (HOMA-IR), which
allows evaluating insulin resistance, was also calculated
according to the following formula: fasting insulin (μUI / mL)
x fasting glucose (mmol / L) / 22.5.27,28
The Systolic blood pressure (SBP) evaluation was assessed
in conscious rats by the non-invasive tail-cuff method
with a NarcoBioSystems® Electro-Sphygmomanometer
(International Biomedical, Austin, TX, USA). The animals were
warmed in a wooden box (50 x 40 cm) between 38–40°C with
heat generated by two incandescent lamps for 4–5 minutes
to stimulate arterial vasodilation. After this procedure, a cuff
with a pneumatic pulse sensor was attached to the tail of each
animal. The cuff was inflated to a pressure of 200 mmHg and
subsequently deflated. Blood pressure values were recorded
on a Gould RS 3200 polygraph (Gould Instrumental Valley
View, Ohio, USA). The mean of three pressure readings was
recorded for each animal.
Since obesity is associated with an inflammatory condition
in adipose tissue, TNF-α and IL-6 levels were evaluated.
Epididymal adipose tissue (400 mg) was triturated with 2 ml
of phosphate buffer saline (PBS) (pH 7.4) and then centrifuged
at 3,000 rpm and 4°C for 10 min. Using the supernatants,
TNF-α and IL-6 were measured using commercial ELISA kits
(R&D Systems) according to the manufacturer’s instructions.
The values were normalized by the protein amounts of
each sample quantified by the Bradford method29 and the
results are expressed in picogram/g protein (pg/g protein).
Epididymal adipose tissue was selected for presenting a similar
inflammation pattern to that found in visceral fat.30
Echocardiographic Analysis
The analysis was performed on live animals by transthoracic
echocardiography, with a Vivid S6 system equipped with a
multifrequency ultrasonic transducer of 5.0 to 11.5 MHz
(General Electric Medical Systems, Tirat Carmel, Israel). The
animals were lightly anesthetized by intraperitoneal injection
with a mixture of ketamine (50 mg/kg) and xylazine (1 mg/
kg) and placed in a left decubitus position. The structural
measurements of cardiac images were obtained in the
one-dimensional mode (M-mode) guided by the images
Arq Bras Cardiol. 2021; 117(1):91-99 93
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
in the two-dimensional mode with the transducer in the
parasternal position, minor axis. Left ventricular (LV) evaluation
was performed with the M-mode cursor just below the
mitral valve plane at the level of the papillary muscles. All
examinations were performed by the same examiner and
obtained according to the main method recommended by
the American Society of Echocardiography. The aorta and
left atrium images were obtained by positioning the M-mode
cursor to plan the aortic valve level. The following cardiac
structures were evaluated: left ventricular diastolic diameter
(LVDD); left ventricular posterior wall thickness at end-systole
(LVPWS); Left ventricular systolic interventricular septum
thickness (LVSIS); aorta diameter (AD); left atrium (LA); and
the relative wall thickness (RWT) of the LV. The LV systolic
function was evaluated by cardiac output and also by heart
rate (HR), since it is a cardiac systolic function modulator. The
LV diastolic function was assessed by the transmitral flow early
peak velocity (E); deceleration time of E wave (Dec. time). The
study was supplemented by evaluation by early (E’) and late
(A’) diastolic tissue Doppler of the mitral annulus (arithmetic
mean travel speeds of lateral and septal walls), and the wave
ratio (E/E’ and E’/A’).
Cardiac tissue analysis
Inflammation
One hundred milligrams (100mg) were homogenized
in PBS and the supernatant was used. TNF-α and IL-6
quantification were performed by ELISA using a commercial
kit (Linco Research Inc., R & D Systems, Millipore and B-Brigde
International Inc.). The reading was performed by Spectra Max
190 microplate spectrophotometer (Molecular Devices®,
Sunnyvale, CA, USA). The results were corrected by the total
protein amount according to the Bradford method.
Real time PCR
The frozen left ventricular fragment was homogenized in
TRIzol® for extraction of ribonucleic acid (RNA). Afterward,
the RNA was subjected to reverse transcription, conversion
of RNA to complementary deoxyribonucleic acid (cDNA),
by the action of the enzyme reverse transcriptase, using the
SuperScript II First-Strand Synthesis System for RT-PCR®
Invitrogen, São Paulo, Brazil. The obtained cDNA was used in
the polymerase chain reaction (PCR) using ready-made assays
(Applied Biosystems, CA, USA) containing TaqMan MGB (FAM)
primer and primer specific for TLR-4 (Rn00569848_m1).
Western Blot
The heart fragments were homogenized in lysis buffer and
centrifuged. The supernatant was collected and the protein
concentration was analyzed by the Bradford method.29 After
quantification, the cardiac protein extracts were diluted in
a buffer solution containing 50 mM Tris-HCl (pH 6.8), 200
mM 2-Mercaptoethanol, 2% Sodium Dodecyl Sulfate (SDS),
0.1% bromophenol blue, and 10% glycerol. The dilutions
(50ug) were heated and subjected to sodium dodecyl
sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) in
10% polyacrylamide gels. After electrophoresis, the proteins
were electrotransferred to nitrocellulose membranes (Bio-
Rad Biosciences; NJ, USA). Non-specific binding sites of
the primary antibody to the membrane were blocked by
incubation with 0.5% skimmed-milk powder solution,
dissolved in TBS-T buffer pH 7.4. The membrane was then
washed three times in basal solution and incubated overnight
with TLR-4 specific primary antibody (sc293072), total NF-ĸB
(sc8008), phosphorylated NF-ĸB (ser536) (sc33020). β- actin
was used as an internal control (sc47778). After incubation, the
membranes were washed and incubated with the respective
secondary antibodies. Finally, immunodetection was
performed by the chemiluminescence method, according to
the manufacturer’s instructions (ECL SuperSignal® West Pico
Chemiluminescent Substrate – Thermo Scientific, Rockford, IL,
USA, 34080), and analyzed by means of a densitometer (GS-
710 calibrated imaging densitometer, Bio-Rad lab, CA, USA).
Statistical analysis
The data were submitted to Kolmogorov-Smirnov normality
test. Parametric variables were compared by unpaired
Student’s t-test and the results are expressed as mean ±
standard deviation. Non-parametric variables were compared
by Mann- Whitney test and the results are expressed as median
(interquartile range 25-75). Statistical analyses were performed
using Sigma Stat for Windows, version 3.5 (Systat Software
Inc., San Jose, CA, USA). A p-value < 0.05 was considered
statistically significant.
Results
Table 1 shows the nutritional parameters. OB animals
consumed less food, but more water compared to the control
group, reflecting a similar caloric intake. The OB group also
presented obesity characterized by increased body weight
and adiposity index.
Regarding the obesity-related disorders, the OB group
presented higher glucose, triglycerides, and uric acid, insulin
resistance, increased systolic blood pressure, and adipose
tissue inflammation, with elevated TNF-α and IL-6 levels
compared to the control group (Table 2).
The echocardiographic analysis is presented in Table
3. At the end of 30 weeks, the OB group showed cardiac
remodeling, characterized by reduced LVDD and increased
LVPWS, LVSIS, LA, and AD. Moreover, OB animals presented
diastolic dysfunction, represented by changes in the E wave,
E wave deceleration time, and E’/A’.
Regarding the TLR-4 gene and protein expression in cardiac
tissue, it is possible to verify that both were increased in the
OB group (Figure 1).
NF-ĸB phosphorylation in cardiac tissue was also higher in
the OB group (Figure 2), resulting in increased cytokines, since
this group showed higher TNF-α and IL-6 levels compared to
the C group (Figure 3).
Discussion
This study hypothesized that the TLR-4 receptor activation
participates in obesity-related cardiac disease by triggering
cytokine production via NF-ĸB. In order to induce obesity and
Arq Bras Cardiol. 2021; 117(1):91-99
94
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
disorders related to excessive body fat, the animals in the OB
group were submitted to a HSF diet for 30 weeks. At the end
of the experimental period, the results show that these animals
presented higher adiposity index and several disorders, such
as hyperglycemia, increased uric acid, insulin resistance,
hypertriglyceridemia, elevated SBP, increased TNF-α and
IL-6 levels in both heart and adipose tissue, confirming the
efficacy of the diet model used. 22–25
The coexistence of obesity-related disorders — such as
insulin resistance, diabetes, and dyslipidemia — associated
with adipose tissue dysfunction, characterized by adipokine
imbalance, promote maladaptive responses in the heart, such
as myocyte hypertrophy, contractile dysfunction, and cardiac
remodeling, which contribute to both the development and
progression of chronic heart failure.31–33 This condition was
confirmed in this study, since the echocardiogram evaluation
showed cardiac remodeling and diastolic dysfunction in the
OB group. It is important to emphasize that the concentric
characteristics of cardiac remodeling observed in the OB
group are the result of an increased functional overload and
the maintenance of this condition, leading to cardiac diastolic
dysfunction. Similar results have been related to the diet-
induced obesity model in the literature.34
The literature reports that cardiac remodeling can also
be led by high concentrations of proinflammatory cytokines,
such as TNF-α and IL-6.35,36 TNF-α has been implicated in the
development of left ventricular dysfunction, left ventricular
remodeling, increased cardiac myocyte apoptosis and its direct
action is exerted by TNF-α receptors, which are expressed by
almost all nucleated cells. Increased IL-6 levels can also induce
myocyte hypertrophy and myocardial dysfunction.37 It is
important to emphasize that these cytokines can be produced
in response to TLR-4 pathway activation, and also L-6 seems
to be released in direct response to TNF-α,35 exacerbating the
cardiac changes due to inflammatory condition. Therefore, our
findings confirm the evidence regarding obesity cardiopathy
and inflammation, since the cardiac levels of TNF-α and IL-6
were higher in the OB group.18,37
The involvement between proinflammatory cytokines and
obesity-related cardiac remodeling induced by diet can be
attributed to several causes.18,38 Thus, the aim of this study
was to evaluate cardiac TLR-4 activation as responsible for
triggering the inflammatory process. It was observed that the
OB group presented higher TLR-4 gene and protein expression
together with increased NF-ĸB phosphorylation, confirming
the activation of this pathway as a mediator of inflammation.
The literature reports that this receptor can be activated by LPS
of gram-negative bacteria, but also by fatty acids.39 In obesity,
the adipose tissue lipolysis represents an important source
of free fatty acids, capable of activating the inflammatory
pathway.40,41 This catabolic process can occur due to insulin
Table 1 – Nutritional parameters
Characteristics Groups
Control (n=8) OB (n=8) p value
Final body weight (g) 493 ± 50.8 583 ± 75.9 0.001*
Adiposity index (%) 4.79 ± 0.73 8.68 ± 1.76 0.0004*
Food consumption (g/day) 23.92 ± 2.37 13.0 ± 2.20 0.0001*
Water consumption (ml/day) 34.6 ± 5.08 41.6 ± 3.47 0.001*
Caloric intake (Kcal/day) 85.9 ± 8.52 98.3 ± 8.35 0.07
OB: obese group. Data expressed as mean ± standard deviation. Comparison by unpaired Student’s t-test. *indicates p < 0.05.
Table 2 – Obesity-related disorders
Characteristics GROUPS
Control (n=8) OB (n=8) p-value
Glucose (mg/dL) 75.7 ± 2.02 105 ± 17.9 0.02*
Triglycerides (mg/dL) 63.5 ± 18.6 104 ± 25.4 0.003*
Uric acid (mg/dL) 0.44 ± 0.09 0.62 ± 0.20 0.04*
HOMA-IR 5.90 ± 2.32 30.9 ± 17.0 0.004*
Systolic Blood Pressure (mmHg) 121 ± 5.77 128 ± 6.48 0.03*
TNF-α Adipose tissue (pg/g protein) 52.7 (46.6 – 62.5) 152 (117 – 219) 0.001*
IL-6 Adipose tissue (pg/g protein) 13.0 ± 9.2 94.5 ± 33.3 < 0.001*
OB: obese group; HOMA-IR: Homeostatic Model Assessment. Data expressed as mean ± standard deviation or median (interquartile range).
Comparison by unpaired Student’s t-test or Mann-Whitney. * indicates p < 0.05.
Arq Bras Cardiol. 2021; 117(1):91-99 95
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
Table 3 – Echocardiographic analysis
Characteristics GROUPS
Control OB p-value
LVDD (mm) 7.20 ± 0.20 6.70 ± 0.56 0.031*
LVDD/BW 14.7 ± 1.6 11.9 ± 1.3 0.002*
LVPWS (mm) 3.03 ± 0.31 3.35 ± 0.21 0.033*
LVSIS (mm) 3.35 ± 0.21 3.57 ± 0.19 0.045*
RWT 0.45 ± 0.05 0.51 ± 0.09 0.098
AD (mm) 3.73 ± 0.12 3.99 ± 0.13 0.001*
LA (mm) 4.75 ± 0.12 5.17 ± 0.38 0.011*
HR (bpm) 234 ± 39 295 ± 26 0.002*
Cardiac Output 0.91 ± 0.01 0.88 ± 0.06 0.142
Deceleration time (ms) 47.2 ± 3.0 50.6 ± 2.7 0.035*
E wave 68.3 ± 5.2 73.1 ± 3.3 0.046*
A wave 40.7 ± 3.7 45.7 ± 6.1 0.062
E/A ratio 1.68 ± 0.08 1.61 ± 0.016 0.327
E'/A' medium ratio 1.53 ± 0.14 1.26 ± 0.25 0.018*
E/ E’ medium ratio 12 ± 1.3 13.5 ± 1.86 0.094
OB: obese group; LVDD: left ventricular diastolic dysfunction; BW: body weight; LVPWS: left ventricular posterior wall thickness at end-systole; LVSIS:
left ventricular systolic interventricular septum thickness; RWT: relative wall thickness; AD: aorta diameter; LA: left atrium; HR: heart rate. Transmitral
flow early peak velocity (E wave); deceleration time: deceleration time of the E wave. Doppler early (E’) and late (A’) diastolic of the mitral annulus
(arithmetic average travel speeds of lateral and septal walls), and the ratio (E/E’ and E’/A’). Data expressed as mean ± standard deviation. Comparison
by unpaired Student’s t-test. * indicates p < 0.05.
Figure 1 – TLR-4 expression in cardiac tissue. (A) Gene expression by real-time PCR; (B) Protein expression by Western Blot. Results expressed as mean
± standard deviation. Comparison by unpaired Student’s t-test. * indicates p < 0.05; n = 8 animals/group.
Arq Bras Cardiol. 2021; 117(1):91-99
96
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
Figure 2 – Phospho and total NF-ĸB protein expression in cardiac tissue. Results expressed as mean ± standard deviation. Comparison by unpaired
Student’s t-test. *indicates p < 0.05; n = 8 animals/group.
Figure 3 – Cardiac cytokines in cardiac tissue. (A) IL-6 (pg protein/g); (B) TNF-α. Results expressed as median and interquartile range. Comparison by
Mann-Whitney test. * indicates p < 0.05; n = 8 animals/group.
Arq Bras Cardiol. 2021; 117(1):91-99 97
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
resistance, once the adipose tissue becomes resistant to the
hormone antilipolytic effect. Together with insulin resistance,
increased TNF-α and IL-6 levels are also able to induce lipolysis
in adipose tissue.42,43 These two lipolytic conditions were
presented by the OB group. Moreover, associated with these
mechanisms described above, some researchers report that the
Western diet pattern is associated with changes in the intestinal
microbiota, making this organ more permeable, allowing
the translocation of pathogenic bacteria to the circulation.42
Bacterial LPS can be recognized by TLR-4, triggering the NF-
ĸB activation with consequent cytokine synthesis. Although
this mechanism was not evaluated in this experiment, this
relationship is already well established.43–45 In addition, the
diet composition used in this study is also directly related to
the TLR-4 receptor activation, since the saturated fatty acids
offered in the diet have similar structures to bacterial LPS,
being also able to be recognized, leading to an inflammatory
process via TLR-4 pathway.46,47
Conclusion
In summary, all these mechanisms may have been
activated in a synergistic way, enhancing the production of
cytokines that play a fundamental role in the development
of cardiomyopathies. Thus, this study shows that the innate
immune response through TLR-4 receptor activation is one
of the mechanisms that can contribute to the onset of the
myocardial inflammatory process in obesity. Therefore,
since no studies were found in the literature showing an
interaction between this inflammatory pathway, heart disease
and obesity, our findings conclude that in an obesogenic
condition, the inflammation derivative from cardiac TLR-4
activation is a new mechanism which can lead to remodeling
and cardiac dysfunction.
Acknowledgments
The authors thank Fundação de Amparo à Pesquisa do
Estado de São Paulo (FAPESP) (2016/13592-1; 2015/10626-
0) and Unidade de Pesquisa Experimental (UNIPEX) from the
Botucatu School of Medicine (UNESP), Botucatu.
Study limitations
This study has few limitations. One of them is related to
the absence of plasma fat-free acid evaluation.
Author Contributions
Conception and design of the research: Ferron AJT, Campos
DHS, Cicogna AC, Francisqueti F, Corrêa C; Acquisition of
data: Alves PHR, Costa MR, Hasimoto FK, Gregolin C, Garcia
JL, Campos DHS, Mattei L, Moreto F, Bazan SGZ; Analysis and
interpretation of the data: Alves PHR, Ferron AJT, Campos
DHS, Bazan SGZ, Francisqueti F, Corrêa C; Statistical analysis:
Ferron AJT; Obtaining financing: Corrêa C; Writing of the
manuscript: Alves PHR, Ferron AJT, Francisqueti F, Corrêa C;
Critical revision of the manuscript for intellectual contente:
Ferron AJT, Cicogna AC, Francisqueti F, Corrêa C.
Potential Conflict of Interest
No potential conflict of interest relevant to this article was
reported.
Sources of Funding
This study was partially funded by Fundação de Amparo
à Pesquisa do Estado de São Paulo (FAPESP) (2016/13592-1;
2015/10626-0)
Study Association
This study is not associated with any thesis or dissertation work.
1. World Health Organization. Obesity and overweight [Internet]. Geneva:
WHO; 2011 [acesso 5 de maio de 2016]. Disponível em: http://www.who.
int//mediacentre/factsheets/fs311/en. 2016
2. Francischi RPP, Pereira LO, Freitas CS, Klopfer M, Santos RC, Vieira P, et al.
Obesidade: atualização sobre sua etiologia, morbidade e tratamento. Rev
Nutr. 2000;13(1):17-28.
3. Bhat ZF, Morton JD, Mason S, Bekhit AEDA, Bhat HF. Obesity and
neurological disorders: dietary perspective of a global menace. Crit Rev
Food Sci Nutr. 2019;59(8):1294-310.
4. Mandviwala T, Khalid U, Deswal A. Obesity and cardiovascular disease : a
risk factor or a risk marker ? Curr Atheroscler Rep. 2016;18(5):21.
5. Johnson AR, Wilkerson MD, Sampey BP, Troester MA, Hayes DN, Makowski
L. Cafeteria diet-induced obesity causes oxidative damage in white adipose.
Biochem Biophys Res Commun. 2016;473(2):545-50.
6. Bray GA, Nielsen SJ, Popkin BM. Consumption of high-fructose corn syrup
in beverages may play a role in the epidemic of obesity. Am J Clin Nutr.
2004;79(4):537-43.
7. Manna P, Jain SK. Obesity, oxidative stress, adipose tissue dysfunction, and
the associated health risks: causes and therapeutic strategies. Metab Syndr
Relat Disord. 2015;13(10):423-44.
8. Blüher M. Adipose tissue dysfunction in obesity. Exp Clin Endocrinol
Diabetes. 2009;117(6):241-50.
9. Skurk T, Alberti-Huber C, Herder C, Hauner H. Relationship between
adipocyte size and adipokine expression and secretion. J Clin Endocrinol
Metab. 2007;92(3):1023-33.
10. Kramer B, França LM, Zhang Y, Paes AM de A, Martin Gerdes A, Carrillo-
Sepulveda MA. Western diet triggers toll-like receptor 4 signaling-induced
endothelial dysfunction in female wistar rats. Am J Physiol Heart Circ Physiol.
2018;315(6):H1735-47.
11. Del Bas JM, Guirro M, Boqué N, Cereto A, Ras R, Crescenti A, et al.
Alterations in gut microbiota associated with a cafeteria diet and the
physiological consequences in the host. Int J Obes. 2018;42(4):746-54.
12. Huang S, Rutkowsky JM, Snodgrass RG, Ono-Moore KD, Schneider
DA, Newman JW, et al. Saturated fatty acids activate TLR-mediated
proinflammatory signaling pathways. J Lipid Res. 2012;53(9):2002-13.
References
Arq Bras Cardiol. 2021; 117(1):91-99
98
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
13. Ferraz EG, Silveira BBB, Sarmento VA, Santos JN. Toll-Like Receptors :
regulation of the immune responses. Rev Gaúcha Odontol.
2011;59(3):483-90.
14. Yuan X, Deng Y, Guo X, Shang J, Zhu D, Liu H. Atorvastatin attenuates
myocardial remodeling induced by chronic intermittent hypoxia in rats:
partly involvement of TLR-4/MYD88 pathway. Biochem Biophys Res
Commun. 2014;446(1):292-7.
15. Frantz S, Kobzik L, Kim Y, Fukazawa R, Medzhitov R, Lee RT, et al. Toll4 (
TLR4 ) expression in cardiac myocytes in normal and failing myocardium.
1999;104(3):271-80.
16. Liu T, Zhang M, Niu H, Liu J, Ruilian M, Wang Y, et al. Astragalus
polysaccharide from Astragalus Melittin ameliorates inflammation via
suppressing the activation of TLR-4/NF-κB p65 signal pathway and protects
mice from CVB3-induced virus myocarditis. Int J Biol Macromol. 2019 Apr
1;126:179-86.
17. Liu F, Wen Y, Kang J, Wei C, Wang M, Zheng Z, et al. Regulation of TLR4
expression mediates the attenuating effect of erythropoietin on inflammation
and myocardial fibrosis in rat heart. Int J Mol Med. 2018;42(3):1436-44.
18. Zhang WB, Zhang HY, Zhang Q, Jiao FZ, Zhang H, Wang LW, et al. Glutamine
ameliorates lipopolysaccharide-induced cardiac dysfunction by regulating
the toll-like receptor 4/mitogen-activated protein kinase/nuclear factor-κB
signaling pathway. Exp Ther Med. 2017;14(6):5825-32.
19. Fuster JJ, Ouchi N, Gokce N, Walsh K. Obesity-induced changes in adipose
tissue microenvironment and their impact on cardiovascular disease. Circ
Res. 2016;118(11):1786-808.
20. Krejci J, Mlejnek D, Sochorova D, Nemec P. Inflammatory cardiomyopathy :
a current view on the pathophysiology , diagnosis , and treatment. Biomed
Res Int. 2016;2016(4087632).
21. Li F, Zhang H, Yang L, Yong H, Qin Q, Tan M, et al. NLRP3 deficiency
accelerates pressure overload-induced cardiac remodeling via increased
TLR4 expression. J Mol Med. 2018;96(11):1189-202.
22. Francisqueti FV, Ferron AJT, Hasimoto FK, Alves PHR, Garcia JL, Santos KC,
et al. Gamma oryzanol treats obesity- induced kidney injuries by modulating
the adiponectin receptor 2 / PPAR- α axis. Oxid Med Cell Longev. 2018 Sep
05;2:1-9.
23. Costa MR, Garcia JL, Silva CCV, Ferron AJT, Francisqueti-Ferron FV, Hasimoto
FK, et al. Lycopene modulates pathophysiological processes of non-alcoholic
fatty liver disease in obese rats. Antioxidants. 2019;8(8):276.
24. Ferron AJT, Aldini G, Francisqueti-Ferron FV, Silva CCVA, Bazan SGZ, Garcia
JL, et al. Protective effect of tomato-oleoresin supplementation on oxidative
injury recoveries cardiac function by improving β-adrenergic response in a
diet-obesity induced model. Antioxidants. 2019;8(9):368.
25. Francisqueti FV, Minatel IO, Ferron AJT, Bazan SGZ, Silva VS, Garcia JL, et
al. Effect of gamma-oryzanol as therapeutic agent to prevent cardiorenal
metabolic syndrome in animals submitted to high sugar-fat diet. Nutrients.
2017;9(12):1299.
26. Olfert ED, Cross BM, McWilliam AA. Guide to the care and use of
experimental animals. Vol. 1. Ottawa: Canadian Council on Animal Care;
1993.
27. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC.
Homeostasis model assessment: insulin resistance and beta-cell function
from fasting plasma glucose and insulin concentrations in man. Diabetologia.
1985;28(7):412-9.
28. Ferron A, Jacobsen BB, Sant’Ana P, Campos D, Tomasi L, Luzivotto R, et
al. Cardiac dysfunction induced by obesity is not related to β -adrenergic
system impairment at the receptor-signalling pathway. PLoS One.
2015;10(9):e0138605.
29. Bradford MM. A rapid and sensitive method for the quantitation of
microgram quantities of protein utilizing the principle of protein-dye
binding. Anal Biochem. 1976;72(1-2):248-54.
30. Luvizotto RAM, Nascimento AF, Imaizumi E, Pierine DT, Conde SJ, Correa
CR, et al. Lycopene supplementation modulates plasma concentrations and
epididymal adipose tissue mRNA of leptin , resistin and IL-6 in diet-induced
obese rats. Br J Nutr. 2013;110(10):1803-9.
31. Jacob PS, Fujii TMM, Yamada M, Borges MC, Pantaleão LC, Borelli P,
et al. Isocaloric intake of a high-fat diet promotes insulin resistance and
inflammation in Wistar rats. Cell Biochem Funct. 2013;31(3):244-53.
32. Lawler HM, Underkofler CM, Kern PA, Erickson C, Bredbeck B, Rasouli
N. Adipose tissue hypoxia, inflammation and fibrosis in obese insulin
sensitive and obese insulin resistant subjects. J Clin Endocrinol Metab.
2016;101(4):1422-8.
33. Moreno-Fernández S, Garcés-Rimón M, Vera G, Astier J, Landrier JF,
Miguel M. High fat/high glucose diet induces metabolic syndrome in an
experimental rat model. Nutrients. 2018;10(10):1502.
34. Ferron AJT, Francisqueti FV, Minatel IO, Silva CCVA, Bazan SGZ, Kitawara
KAH, et al. Association between cardiac remodeling and metabolic alteration
in an experimental model of obesity induced by Western Diet. Nutrients.
2018;10(11):1675.
35. Hedayat M, Mahmoudi MJ, Rose NR, Rezaei N. Proinflammatory cytokines
in heart failure: double-edged swords. Heart Fail Rev. 2010;15(6):543-62.
36. Nishida K, Otsu K. Inflammation and metabolic cardiomyopathy. Cardiovasc
Res. 2017;113(4)389-98.
37. Anker SD, Haehling S. Inflammatory mediators in chronic heart failure: an
overview. Heart. 2004;90(4):464-70.
38. Mocan M, Mocan Hognogi LD, Anton FP, Chiorescu RM, Goidescu CM,
Stoia MA, et al. Biomarkers of inflammation in left ventricular diastolic
dysfunction. Dis Markers. 2019 Jun 2;2019:7583690.
39. Sopasakis VR, Sandstedt J, Johansson M, Lundqvist A, Bergström G, Jeppsson
A, et al. Toll-like receptor-mediated inflammation markers are strongly
induced in heart tissue in patients with cardiac disease under both ischemic
and non-ischemic conditions. Int J Cardiol. 2019 Oct 15;293:238-47.
40. Francisqueti FV, Nascimento AF, Minatel IO, Dias MC, Luvizotto RDAM,
Berchieri-Ronchi C, et al. Metabolic syndrome and inflammation in adipose
tissue occur at different times in animals submitted to a high-sugar/fat diet.
J Nutr Sci. 2017 Aug 21;6:e41.
41. Ruiz-núñez B, Dijck-Brouwer DAJ, Muskiet FAJ. The relation of saturated
fatty acids with low-grade inflammation and cardiovascular disease. J Nutr
Biochem. 2016 Oct;36:1-20.
42. Langin D, Arner P. Importance of TNFα and neutral lipases in human adipose
tissue lipolysis. Trends Endocrinol Metab. 2006;17(8):314-20.
43. Hall G, Steensberg A, Sacchetti M, Fischer C, Keller C, Schjerling P, et
al. Interleukin-6 stimulates lipolysis and fat oxidation in humans. J Clin
Endocrinol Metab. 2003;88(7):3005-10.
44. Rinninella E, Cintoni M, Raoul P, Lopetuso LR, Scaldaferri F, Pulcini G, et
al. Food components and dietary habits: keys for a healthy gut microbiota
composition. Nutrients. 2019;11(10):2393.
45. Ubanako P, Xelwa N, Ntwasa M. LPS induces inflammatory chemokines via
TLR-4 signalling and enhances the Warburg Effect in THP-1 cells. PLoS One.
2019;14(9):e1222614.
46. Li P, Wu YH, Zhu YT, Li MX, Pei HH. Requirement of Rab21 in LPS-induced
TLR4 signaling and pro-inflammatory responses in macrophages and
monocytes. Biochem Biophys Res Commun. 2019;508(1):169-76.
47. Fonceca AM, Zosky GR, Bozanich EM, Sutanto EN, Kicic A, McNamara
PS, et al. Accumulation mode particles and LPS exposure induce TLR-4
dependent and independent inflammatory responses in the lung. Respir
Res. 2018;19(15):1-10.
Arq Bras Cardiol. 2021; 117(1):91-99 99
Original Article
Alves et al.
TLR-4 and obesity cardiomyopathy
This is an open-access article distributed under the terms of the Creative Commons Attribution License
... LPS can also stimulate nonimmune cells and initiate the inflammatory process. The literature reports that an innate LPS-pattern recognition receptor, the Toll-like receptor-4 (TLR-4) is widely expressed in the body, including cardiac tissue 13 . Thus, the innate inflammatory response can be induced in cardiomyocytes by LPS independently of the immune cell involvement 14 . ...
... These changes are associated with the reprogramming of mitochondrial metabolism in adipose tissues. Furthermore, TLRs such as TLR4 and TLR9 contribute to obesity-associated metabolic disorders [82,83]. ...
Article
Full-text available
Obesity is a chronic disease characterized by the abnormal or excessive accumulation of body fat, affecting more than 1 billion people worldwide. Obesity is commonly associated with other metabolic disorders, such as type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular diseases, chronic kidney disease, and cancers. Factors such as a sedentary lifestyle, overnutrition, socioeconomic status, and other environmental and genetic conditions can cause obesity. Many molecules and signaling pathways are involved in the pathogenesis of obesity, such as nuclear factor (NF)-κB, Toll-like receptors (TLRs), adhesion molecules, G protein-coupled receptors (GPCRs), programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1), and sirtuin 1 (SIRT1). Commonly used strategies of obesity management and treatment include exercise and dietary change or restriction for the early stage of obesity, bariatric surgery for server obesity, and Food and Drug Administration (FDA)-approved medicines such as semaglutide and liraglutide that can be used as monotherapy or as a synergistic treatment. In addition, psychological management, especially for patients with obesity and distress, is a good option. Gut microbiota plays an important role in obesity and its comorbidities, and gut microbial reprogramming by fecal microbiota transplantation (FMT), probiotics, prebiotics, or synbiotics shows promising potential in obesity and metabolic syndrome. Many clinical trials are ongoing to evaluate the therapeutic effects of different treatments. Currently, prevention and early treatment of obesity are the best options to prevent its progression to many comorbidities.
... The obesity-related disorders, such as insulin resistance, diabetes, and dyslipidemia, are considered HF predictors and associate with adipose tissue dysfunction, promoting maladaptive cardiac responses, such as myocyte hypertrophy, contractile dysfunction, and cardiac remodeling, which contribute to their development and chronic HF progression. 40 Alves et al., 41 in an elegant study with Wistar rats, have hypothesized that the activation of the toll-like receptor 4 (TLR-4) participates in the obesity-related cardiac disease by triggering cytokine production via nuclear factor-ĸB (NF-ĸB). The 'obese' group, which was fed a high sugar-fat diet and water plus 25% of sucrose for 30 weeks, showed: obesity, high levels of glucose, triglycerides and uric acid, insulin resistance, high systolic blood pressure, high levels of tumor necrosis factor alpha (TNF-α) in the adipose tissue, in addition to cardiac remodeling and diastolic dysfunction. ...
... The obesity-related disorders, such as insulin resistance, diabetes, and dyslipidemia, are considered HF predictors and associate with adipose tissue dysfunction, promoting maladaptive cardiac responses, such as myocyte hypertrophy, contractile dysfunction, and cardiac remodeling, which contribute to their development and chronic HF progression. 40 Alves et al., 41 in an elegant study with Wistar rats, have hypothesized that the activation of the toll-like receptor 4 (TLR-4) participates in the obesity-related cardiac disease by triggering cytokine production via nuclear factor-ĸB (NF-ĸB). The 'obese' group, which was fed a high sugar-fat diet and water plus 25% of sucrose for 30 weeks, showed: obesity, high levels of glucose, triglycerides and uric acid, insulin resistance, high systolic blood pressure, high levels of tumor necrosis factor alpha (TNF-α) in the adipose tissue, in addition to cardiac remodeling and diastolic dysfunction. ...
Article
1-Octacosanol (Octa) is reported to possess many physiological properties. However, its relative mechanism has not been illustrated yet. Herein, we aimed to investigate the effect of Octa on insulin resistance in mice fed with a high fat diet (HFD) and used an in vitro simulated gastrointestinal tract to analyze its digestive behavior. The effects of Octa on the gut microbiota were verified by in vitro fermentation using the mouse fecal microbiota. As a result, the Octa monomer was digested into shortened saturated and unsaturated fatty acids (C10-C24) in the simulated gastrointestinal tract. Octa improved the fasting blood glucose (FBG), insulin resistance (IR), plasma lipids, and inflammatory response in HFD-fed mice in a dose-dependent manner. This study also suggested that a high-dose of Octa effectively decreased the levels of toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in the plasma of HFD-fed mice. Octa improved the oxidative stress induced by a HFD and increased the expression of the Nrf2/ARE signaling pathway. Importantly, Octa reshaped gut microbiota through decreasing Firmicutes content and increasing Bacteroidota and Verrucomicrobiota contents at the phylum level, and the changes of intestinal flora structure caused by Octa were significantly correlated with the changes of inflammatory biomarkers. In conclusion, the effects of Octa on insulin resistance might be attributed to the reconstruction of the gut microbiota structure and inhibition of the TLR4/NF-κB inflammatory pathway in HFD-induced obese individuals.
Article
Full-text available
The gut microbiota is a changing ecosystem, containing trillions of bacteria, continuously shaped by many factors, such as dietary habits, seasonality, lifestyle, stress, antibiotics use, or diseases. A healthy host–microorganisms balance must be respected in order to optimally maintain the intestinal barrier and immune system functions and, consequently, prevent disease development. In the past several decades, the adoption of modern dietary habits has become a growing health concern, as it is strongly associated with obesity and related metabolic diseases, promoting inflammation and both structural and behavioral changes in gut microbiota. In this context, novel dietary strategies are emerging to prevent diseases and maintain health. However, the consequences of these different diets on gut microbiota modulation are still largely unknown, and could potentially lead to alterations of gut microbiota, intestinal barrier, and the immune system. The present review aimed to focus on the impact of single food components (macronutrients and micronutrients), salt, food additives, and different dietary habits (i.e., vegan and vegetarian, gluten-free, ketogenic, high sugar, low FODMAP, Western-type, and Mediterranean diets) on gut microbiota composition in order to define the optimal diet for a healthy modulation of gut microbiota.
Article
Full-text available
The Warburg Effect has emerged as a potential drug target because, in some cancer cell lines, it is sufficient to subvert it in order to kill cancer cells. It has also been shown that the Warburg Effect occurs in innate immune cells upon infection. Innate immune cells play critical roles in the tumour microenvironment but the Warburg Effect is not fully understood in monocytes. Furthermore, it is important to understand the impact of infections on key players in the tumour microenvironment because inflammatory conditions often precede carcinogenesis and mutated oncogenes induce inflammation. We investigated the metabolic programme in the acute monocytic leukaemia cell line, THP-1 in the presence and absence of lipopolysaccharide, mimicking bacterial infections. We found that stimulation of THP-1 cells by LPS induces a subset of pro-inflammatory chemokines and enhances the Warburg Effect. Surprisingly, perturbation of the Warburg Effect in these cells does not lead to cell death in contrast to what was observed in non-myeloid cancer cell lines in a previous study. These findings indicate that the Warburg Effect and inflammation are activated by bacterial lipopolysaccharide and may have a profound influence on the microenvironment.
Article
Full-text available
The system redox imbalance is one of the pathways related to obesity-related cardiac dysfunction. Lycopene is considered one of the best antioxidants. The aim of this study was to test if the tomato-oleoresin would be able to recovery cardiac function by improving β-adrenergic response due its antioxidant effect. A total of 40 animals were randomly divided into two experimental groups to receive either the control diet (Control, n = 20) or a high sugar-fat diet (HSF, n = 20) for 20 weeks. Once cardiac dysfunction was detected by echocardiogram in the HSF group, animals were re- divided to begin the treatment with Tomato-oleoresin or vehicle, performing four groups: Control (n = 6); (Control + Ly, n = 6); HSF (n = 6) and (HSF + Ly, n = 6). Tomato oleoresin (10 mg lycopene/kg body weight (BW) per day) was given orally every morning for a 10-week period. The analysis included nutritional and plasma biochemical parameters, systolic blood pressure, oxidative parameters in plasma, heart, and cardiac analyses in vivo and in vitro. A comparison among the groups was performed by two-way analysis of variance (ANOVA). Results: The HSF diet was able to induce obesity, insulin-resistance, cardiac dysfunction, and oxidative damage. However, the tomato-oleoresin supplementation improved insulin-resistance, cardiac remodeling, and dysfunction by improving the β-adrenergic response. It is possible to conclude that tomato-oleoresin is able to reduce the oxidative damage by improving the system’s β-adrenergic response, thus recovering cardiac function.
Article
Full-text available
Background: The higher consumption of fat and sugar are associated with obesity development and its related diseases such as non-alcoholic fatty liver disease (NAFLD). Lycopene is an antioxidant whose protective potential on fatty liver degeneration has been investigated. The aim of this study was to present the therapeutic effects of lycopene on NAFLD related to the obesity induced by a hypercaloric diet. Methods: Wistar rats were distributed in two groups: Control (Co, n = 12) and hypercaloric (Ob, n = 12). After 20 weeks, the animals were redistributed into the control group (Co, n = 6), control group supplemented with lycopene (Co+Ly, n = 6), obese group (Ob, n = 6), and obese group supplemented with lycopene (Ob+Ly, n = 6). Ob groups also received water + sucrose (25%). Animals received lycopene solution (10 mg/kg/day) or vehicle (corn oil) via gavage for 10 weeks. Results: Animals which consumed the hypercaloric diet had higher adiposity index, increased fasting blood glucose, hepatic and blood triglycerides, and also presented in the liver macro and microvesicular steatosis, besides elevated levels of tumor necrosis factor-α (TNF-α). Lycopene has shown therapeutic effects on blood and hepatic lipids, increased high-density lipoprotein cholesterol (HDL), mitigated TNF-α, and malondialdehyde (MDA) and further improved the hepatic antioxidant capacity. Conclusion: Lycopene shows therapeutic potential to NAFLD.
Article
Full-text available
Left ventricular diastolic dysfunction (LVDD) is an important precursor to many different cardiovascular diseases. Diastolic abnormalities have been studied extensively in the past decade, and it has been confirmed that one of the mechanisms leading to heart failure is a chronic, low-grade inflammatory reaction. The triggers are classical cardiovascular risk factors, grouped under the name of metabolic syndrome (MetS), or other systemic diseases that have an inflammatory substrate such as chronic obstructive pulmonary disease. The triggers could induce myocardial apoptosis and reduce ventricular wall compliance through the release of cytokines by multiple pathways such as (1) immune reaction, (2) prolonged cell hypoxemia, or (3) excessive activation of neuroendocrine and autonomic nerve function disorder. The systemic proinflammatory state causes coronary microvascular endothelial inflammation which reduces nitric oxide bioavailability, cyclic guanosine monophosphate content, and protein kinase G (PKG) activity in adjacent cardiomyocytes favoring hypertrophy development and increases resting tension. So far, it has been found that inflammatory cytokines associated with the heart failure mechanism include TNF- α , IL-6, IL-8, IL-10, IL-1 α , IL-1 β , IL-2, TGF- β , and IFN- γ . Some of them could be used as diagnosis biomarkers. The present review aims at discussing the inflammatory mechanisms behind diastolic dysfunction and their triggering conditions, cytokines, and possible future inflammatory biomarkers useful for diagnosis.
Article
Full-text available
The high consumption of fat and sugar contributes to the development of obesity and co-morbidities, such as dyslipidemia, hypertension, and cardiovascular disease. The aim of this study was to evaluate the association between dyslipidemia and cardiac dysfunction induced by western diet consumption. Wistar rats were randomly divided into two experimental groups and fed ad libitum for 20 weeks with a control diet (Control, n = 12) or a high-sugar and high-fat diet (HSF, n = 12). The HSF group also received water + sucrose (25%). Evaluations included feed and caloric intake; body weight; plasma glucose; insulin; uric acid; HOMA-IR; lipid profile: [total cholesterol (T-chol), high-density lipoprotein (HDL), non-HDL Chol, triglycerides (TG)]; systolic blood pressure, and Doppler echocardiographic. Compared to the control group, animals that consumed the HSF diet presented higher weight gain, caloric intake, feed efficiency, insulin, HOMA-IR, and glucose levels, and lipid profile impairment (higher TG, T-chol, non-HDL chol and lower HDL). HSF diet was also associated with atrial-ventricular structural impairment and systolic-diastolic dysfunction. Positive correlation was also found among the following parameters: insulin versus estimated LV mass (r = 0.90, p = 0.001); non-HDL versus deceleration time (r = 0.46, p = 0.02); TG versus deceleration time (r = 0.50, p = 0.01). In summary, our results suggest cardiac remodeling lead by western diet is associated with metabolic parameters.
Article
Full-text available
Metabolic syndrome (MetS) is defined as a constellation of many metabolic disorders such as hypertension, impaired glucose tolerance, dyslipidemia and obesity, being this last disorder a key factor in the etiology of the syndrome. The widespread of MetS in actual society, mainly in developed countries, is becoming an important health problem and is increasing the need to develop new treatments against this pathology is increasing fast. The main objective of the present study was to evaluate the MetS-associated alterations developed in a new glucose diet-induced-obesity (DIO) rodent model. These alterations were also compared to those alterations developed in a fructose-DIO rodent model. Wistar rats were divided into four groups: Control (C), High-fat (HF), High-fat/high-fructose (HFF) and High-fat/high-glucose (HFG). The animals were fed ad libitum for 20 weeks. At the end of the study, HFG animals showed lower expression of energy expenditure genes when compared to the other DIO groups. Oxidative stress biomarkers such as MDA and mitochondrial RT-qPCR analyses showed an increase of oxidative damage together with mitochondrial dysfunction in HFG group. This group also showed increased insulin and glucose plasma levels, though HFF animals showed the greatest increase on these parameters. All DIO groups showed increased plasma levels of triglycerides. Altogether, our results indicated a better impact of glucose than fructose, when combined with a high-fat diet, to induce most of the alterations associated with MetS in rats. In addition, our research facilitates a new animal model to evaluate future treatments for MetS.
Article
Background: A sustained low grade inflammatory state is a recognized feature of various diseases, including cardiovascular disease. This state of chronic inflammation involves activation of Toll-like receptor (TLR) signaling. However, little is known regarding the genetic profile of TLR components in cardiac tissue from patients with cardiac disease. Methods: In this study we investigated the genetic profile of 84 TLR markers in a unique set of cardiac tissue from patients that had undergone either coronary artery bypass grafting (CABG) or aortic valve replacement (AVR). In addition, we compared the gene data from the cardiac tissue with the same gene profile in blood as well as circulating cytokines to elucidate possible targets in blood that could be used to estimate the inflammatory state of the heart in cardiac disease. Results: We found a marked upregulation of TLR-induced inflammation in cardiac tissue from both patient groups compared to healthy controls. The inflammation appeared to be primarily mediated through TLR1, 3, 7, 8 and 10, resulting in a marked induction of mediators of the innate immune response. Furthermore, the gene expression data in combination with unbiased multivariate analysis suggested a difference in inflammatory response in ischemic cardiac tissue compared to non-ischemic cardiac tissue. Serum levels of IL-13 were significantly elevated in both CABG and AVR patients compared to controls, whereas other cytokines did not appear to coincide with cardiac TLR-induced inflammation. Conclusions: We propose that cardiac disease in humans may be mediated by local cardiac TLR signaling under both ischemic and non-ischemic conditions.
Article
Inflammation plays a crucial role in regulating cardiomyopathy and injuries of coxsackievirus B3 (CVB3)-induced viral myocarditis (VM). It has been reported that Astragalus polysaccharide (AP) from Astragalus Melittin could inhabit inflammatory gene expression under a variety of pathological conditions. However, the functional roles of AP in CVB3-induced VM still remain unknown. Here, we found that AP significantly enhanced survival for CVB3-induced mice. AP protected the mice against CVB3-induced myocardial injuries characterized by the increased body weight and depressed serum level of creatine kinase-MB (CK-MB), aspartate transaminases (AST) and lactate dehydrogenase (LDH), enhanced left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS). At the pathological level, AP ameliorated the mice against CVB3-induced myocardial damage, dilated cardiomyopathy and chronic myocardial fibrosis. We subsequently found that AP significantly suppressed CVB3-induced expression of inflammation marker (IL-1β IL-6, TNF-α INF-γ and MCP-1) in heart. Furthermore, we confirmed that AP suppressed the CVB3-induced expression of TLR-4 and phosphorylated NF-κB p65 in heart. Taken together, the data suggest that AP protects against CVB3-induced myocardial damage and inflammation, which may partly attribute to the regulation of TLR-4/NF-κB p65 signal pathway, moreover, suppressive effect of AP on CVB3-induced activation of TLR-4/NF-κB p65 signal was TNF-α-independent.
Article
Lipopolysaccharide (LPS) induces macrophage/monocyte activation and pro-inflammatory cytokines production by activating Toll-like receptor 4 (TLR-4) signaling. Rab GTPase 21 (Rab21) is a member of the Rab GTPase subfamily. In the present study, we show that LPS induced TLR4 and Rab21 association and endosomal translocation in murine bone marrow-derived macrophages (BMDMs) and primary human peripheral blood mononuclear cells (PBMCs). In BMDMs, shRNA-mediated stable knockdown of Rab21 inhibited LPS-induced expression and production of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α). Conversely, forced overexpression of Rab21 by an adenovirus construct potentiated LPS-induced IL-1β, IL-6 and TNF-α production in BMDMs. Further studies show that LPS-induced TLR4 endosomal traffic and downstream c-Jun and NFκB (nuclear factor-kappa B) activation were significantly inhibited by Rab21 shRNA, but intensified with Rab21 overexpression in BMDMs. Finally, in the primary human PBMCs, siRNA-induced knockdown of Rab21 significantly inhibited LPS-induced IL-1β, IL-6 and TNF-α production. Taken together, we suggest that Rab21 regulates LPS-induced pro-inflammatory responses by promoting TLR4 endosomal traffic and downstream signaling activation.