Avemar, a product of industrial fermentation of wheat germ with a standardized content of benzoquinone and plant flavonoids, has been tested as an anti-cancer and immunomodulatory dietary supplement. Proposed mechanisms include anti-oxidant and anti-inflammatory actions. This study has determined whether these actions of Avemar may also be useful in the treatment of cardiovascular diseases. Two experimental rat models of cardiovascular remodeling were used in this project: the deoxycorticosterone acetate (DOCA)-salt-induced model of chronic hypertension (study I) and a high-carbohydrate/high-fat diet-induced model producing chronic symptoms of the metabolic syndrome and its associated cardiovascular complications (study II). Our results in these rat models of hypertension and diet-induced obesity show that treatment with Avemar improved cardiac function, decreased macrophage infiltration resulting in decreased collagen deposition in the ventricular myocardium, reversed an increased stiffness of the left ventricle in the diseased hearts and attenuated increased plasma malondialdehyde concentrations. In addition to the changes in the heart, Avemar reversed glucose intolerance, normalized systolic blood pressure and decreased visceral fat deposition in rats fed a high-fat/high-carbohydrate diet. In conclusion, the fermented wheat germ extract Avemar has a potential role in attenuating chronic hypertension, diabetes or metabolic syndrome-induced cardiovascular symptoms along with metabolic abnormalities such as glucose tolerance and obesity.
Avemar is a product of industrial fermentation of wheat germ with a standardized content of benzoquinone and plant flavonoids that has been reported as safe and effective as an anti-cancer and immunomodulatory dietary supplement [
Plants have provided many possible treatment options for human hypertension and metabolic diseases [
Since the progression of cardiac remodeling and metabolic diseases is characterized by oxidative stress and chronic inflammation, it is possible that Avemar decreases cardiovascular remodeling, glucose intolerance and fat deposition through its reported anti-oxidant and anti-inflammatory properties. Thus, we have investigated whether dietary treatment with Avemar can regulate cardiovascular remodeling and metabolic responses in hypertensive and diet-induced obese rats. Structural changes in the heart were characterized by histology and echocardiography, whereas heart function was measured
Male Wistar rats were bred at The University of Queensland Biological Resources facility. All experimental protocols were approved by the Animal Experimentation Ethics Committee of The University of Queensland, under the guidelines of the National Health and Medical Research Council of Australia. Rats were given
All the rats in study I were uninephrectomized (UNX). Rats, 8-9 weeks old, were divided into four experimental groups of eight rats each; UNX only or treated with Avemar (4
Study II consisted of three experimental groups of 8-9 weeks old male Wistar rats treated for 16 weeks with corn starch (CS) (
Systolic blood pressure was measured in study I rats after 0, 2 and 4 weeks and in study II rats after 0, 4, 8, 12 and 16 weeks under light sedation with i.p. injection of Zoletil (tiletamine 15 mg/kg, zolazepam 15 mg/kg). Measurements were taken using an MLT1010 Piezo-Electric Pulse Transducer (ADInstruments, Sydney, Australia) and inflatable tail-cuff connected to a MLT844 Physiological Pressure Transducer (ADInstruments) and PowerLab data acquisition unit (ADInstruments).
Fasting blood glucose concentrations were measured for study II animals with blood taken from the tail vein using Medisense Precision Q.I.D glucose meter (Abbott Laboratories, Bedford, USA). The rats were given 40
Plasma malondialdehyde concentrations as a measure of oxidative stress were determined in post-mortem blood by HPLC [
Echocardiography was performed by trained cardiac sonographers at the Small Animal Practice, School of Veterinary Sciences, The University of Queensland or The Prince Charles Hospital, Brisbane, small animal theater. Rats were anesthetized via i.p. injection with Zoletil (tiletamine 15 mg/kg, zolazepam 15 mg/kg) and Ilium Xylazil (xylazine 10 mg/kg). Echocardiographic images of rats were obtained using the Hewlett Packard Sonos 5500 (12 MHz frequency fetal transducer) at an image depth of 3 cm using two focal zones. Measurements of left ventricular posterior wall thickness and internal diameter were made using two-dimensional
The left ventricular function of the rats in all treatment groups was assessed using the Langendorff heart preparation. Terminal anesthesia was induced via i.p. injection of pentobarbitone sodium 100 mg/kg (Lethabarb). Once anesthesia was achieved, heparin (1000 IU) was injected into the right femoral vein. Isovolumetric ventricular function was measured by inserting a latex balloon catheter into the left ventricle connected to a Capto SP844 MLT844 physiological pressure transducer and Chart software on a Maclab system. All left ventricular end-diastolic pressure values were measured by pacing the heart at 250 beats per minute using an electrical stimulator. End-diastolic pressures were obtained starting from 0 mmHg up to 30 mmHg. The right and left ventricles were separated and weighed. Diastolic stiffness constant (
Thoracic aortic rings (4 mm in length) were suspended in an organ bath chamber with a resting tension of 10 mN. Cumulative concentration—response (contraction) curves were measured for noradrenaline; concentration—response (relaxation) curves were measured for acetylcholine and sodium nitroprusside in the presence of a submaximal (70
Following euthanasia, the heart, liver, kidneys, visceral fat pads and spleen were removed and blotted dry for weighing. All organ weights except visceral fat pads were normalized relative to the body weight at the time of their removal (in mg/g). Visceral fat pads were normalized relative to tibial length at the time of removal (in mg/mm).
Collagen distribution was measured in the left ventricle following staining with picrosirius red and analyzed by laser confocal microscopy. Tissues were initially fixed for 3 days in Telly's fixative (100 mL of 70
All data sets were represented as mean ± SEM. Comparisons or findings between groups were made via statistical analysis of data sets using one-way/two-way analysis of variance followed by the Duncan test to determine differences between treatment groups. A
DOCA, heparin, noradrenaline, acetylcholine and sodium nitroprusside were purchased from Sigma Chemical Company (St Louis, MO, USA.) The fermented wheat germ extract, Avemar, was provided by Jenny Blyth, Medimpex Pty Ltd, Mudgeeraba, QLD 4213, Australia and thoroughly mixed in the food to a final concentration of 4
Hypertension developed in DOCA-salt rats together with an increased water intake, but these rats failed to gain weight (Table
Physiological parameters of UNX, UNX + AVE, DOCA and DOCA + AVE-fed rats.
Parameter | UNX (4 weeks) | UNX + AVE (4 weeks) | DOCA (4 weeks) | DOCA + AVE (4 weeks) |
---|---|---|---|---|
Daily water intake (mL) | 67 ± 11 ( | 59 ± 9 ( | 190 ± 33* ( | 125 ± 30** ( |
Daily food intake (g) | 29 ± 2 ( | 27 ± 3 ( | 24 ± 5 ( | 23 ± 5 ( |
Systolic blood pressure | 107 ± 1.3 ( | 113 ± 1.8 ( | 108 ± 3.1 ( | 105 ± 2.1 ( |
Systolic blood pressure | 128 ± 0.7 ( | 145 ± 6* ( | 176 ± 7.0* | 171 ± 6.0* ( |
Systolic blood pressure | 135 ± 1.7 ( | 151 ± 1.0* ( | 186 ± 3.6* | 182 ± 3.0* ( |
LVIDd (cm) | 0.66 ± 0.01 ( | 0.57 ± 0.01* | 0.48 ± 0.02* | 0.51 ± 0.01* ( |
LVPWd (cm) | 0.15 ± 0.01 ( | 0.17 ± 0.01 ( | 0.22 ± 0.01* | 0.22 ± 0.01* ( |
Fractional shortening ( | 54 ± 6 ( | 57 ± 1.4 ( | 58 ± 3 ( | 64 ± 5 ( |
LV mass (g) | 0.7 ± 0.01 ( | 0.63 ± 0.01 ( | 0.85 ± 0.01* ( | 0.75 ± 0.01** ( |
Cardiac output (mL/min) | 56 ± 9 ( | 39 ± 8 ( | 21 ± 3* ( | 27 ± 8* ( |
Ejection fraction ( | 87 ± 3 ( | 92 ± 0.7 ( | 92 ± 2 ( | 92 ± 1.4 ( |
Relative wall thickness | 0.49 ± 0.01 ( | 0.94 ± 0.2* ( | 1.49 ± 0.68* ( | 0.94 ± 0.2** ( |
LV—interstitial collagen | 2.7 ± 0.3 ( | 2.4 ± 0.5 ( | 11.7 ± 1.3* | 3.8 ± 0.7** ( |
LV—perivascular collagen | 25.6 ± 0.9 ( | 26.2 ± 1.1 ( | 36.4 ± 1.3* | 28.1 ± 1.0** ( |
Diastolic stiffness constant ( | 20.3 ± 0.8 ( | 19.7 ± 1.8 ( | 32.3 ± 1.7* ( | 22.6 ± 0.7** ( |
LV + septum (mg/g body wt) | 2.16 ± 0.1 ( | 2.0 ± 0.1 ( | 3.06 ± 0.08* ( | 2.9 ± 0.1* ( |
RV (mg/g body wt) | 0.36 ± 0.01 ( | 0.51 ± 0.01* ( | 0.49 ± 0.01* ( | 0.54 ± 0.01* ( |
Liver (mg/g body wt) | 28.2 ± 1.7 ( | 40.6 ± 1.4 ( | 54 ± 2.0* ( | 45.6 ± 3** ( |
Spleen (mg/g body wt) | 2.4 ± 0.17 ( | 2.4 ± 0.1 ( | 4.3 ± 0.2* ( | 3.1 ± 0.1** ( |
Remnant kidney (mg/g body wt) | 5.1 ± 0.4 ( | 4.0 ± 0.5 ( | 8.2 ± 0.3* ( | 9.3 ± 0.5* ( |
Plasma malondialdehyde | 19.7 ± 0.7 ( | 20.4 ± 0.6 ( | 27.3 ± 0.8* ( | 23.9 ± 0.6** ( |
Values are mean ± SEM; number of experiments in parentheses. LV, left ventricle; RV, right ventricle; LVIDd, left ventricular internal diameter at diastole; LVPWd, left ventricular posterior wall thickness at diastole. LV mass calculated according to [
Hearts from DOCA-salt rats showed marked cardiac hypertrophy, as evidenced by increased left ventricular wet weight relative to body weight and left ventricular mass derived from echocardiography (Table
Echocardiographic assessment of heart function showed that Avemar attenuated the increase in relative wall thickness observed in DOCA-salt rats (Table
Functionally, the increased diastolic stiffness in isolated hearts from DOCA-salt rats was prevented by Avemar treatment (Table
Picrosirius red staining of left ventricular interstitial collagen deposition (magnification,
In isolated thoracic aortic rings, DOCA-salt rats showed decreased contractile responses to noradrenaline (Figure
Cumulative concentration—response curves for noradrenaline (a), sodium nitroprusside (b) and acetylcholine (c) in thoracic aortic rings from UNX (filled square), UNX + AVE (open square), DOCA (filled circle) and DOCA + AVE (open circle)-fed rats after 16 weeks of feeding. *
Young male Wistar rats fed a high-carbohydrate/high-fat diet showed increased body weight, especially with increased abdominal fat pads, compared with CS-fed rats, without an increased food intake (Table
Physiological parameters of CS, CAF+BT and CAF+BT+AVE-fed rats.
Parameter | Corn starch (16 weeks) | CAF + BT (8 weeks) | CAF + BT (16 weeks) | CAF + BT + AVE (16 weeks) |
---|---|---|---|---|
Body weight (g) | 341 ± 13 ( | 448 ± 11 ( | 523 ± 14 ( | 479 ± 8 ( |
Daily water intake (mL) | 24.0 ± 2.4 ( | 19.1 ± 3.0 ( | 21.6 ± 4.0 ( | 19.0 ± 3 ( |
Daily food intake (g) | 29.0 ± 4.3 ( | 26.1 ± 2.8 ( | 22.4 ± 1.8 ( | 22.0 ± 4 ( |
Daily drug intake (g/kg/day) | N/A | N/A | N/A | 1.83 ± 0.25 ( |
Fasting plasma glucose | 3.2 ± 0.5 ( | 3.5 ± 0.1 ( | 4.0 ± 0.1* ( | 3.6 ± 0.1** ( |
Plasma glucose concentration (mmol/L) (after 120 min glucose loading) | 6.0 ± 0.4 ( | 5.9 ± 0.2 ( | 7.0 ± 0.4* ( | 4.4 ± 0.2** ( |
LVIDd (cm) | 0.61 ± 0.02 ( | 0.78 ± 0.01* ( | 0.76 ± 0.02* ( | 0.73 ± 0.01* ( |
LVPWd (cm) | 0.18 ± 0.01 ( | 0.16 ± 0.01 ( | 0.20 ± 0.01 ( | 0.17 ± 0.01 ( |
Fractional shortening ( | 63 ± 2 ( | 44 ± 2* ( | 35 ± 1* ( | 54 ± 2** ( |
Mitral valve flow rate (E/A) ratio | 2.1 ± 0.1 ( | 1.8 ± 0.1 ( | 1.1 ± 0.01* ( | 1.4 ± 0.12** ( |
Estimated LV mass (g) | 0.82 ± 0.06 ( | 0.88 ± 0.03 ( | 1.01 ± 0.05* ( | 0.82 ± 0.03** ( |
LV systolic volume (mL) | 0.046 ± 0.01 ( | 0.09 ± 0.01* ( | 0.127 ± 0.01* ( | 0.040 ± 0.01** ( |
Cardiac output (mL/min) | 93 ± 6 ( | 98 ± 7 ( | 83 ± 9 ( | 105 ± 6 ( |
Ejection fraction ( | 95 ± 0.9 ( | 81 ± 2* ( | 72 ± 1* ( | 90 ± 0.9** ( |
Relative wall thickness | 0.55 ± 0.04 ( | 0.41 ± 0.01* ( | 0.51 ± 0.04 ( | 0.45 ± 0.01** ( |
LV—interstitial collagen | 4.8 ± 0.5 ( | 14.6 ± 1.4* ( | 19.9 ± 1.2* ( | 8.4 ± 0.4** ( |
LV—perivascular collagen | 21.2 ± 1.6 ( | 31.2 ± 2.6* ( | 35.3 ± 3.0* ( | 26.1 ± 1.2** ( |
Diastolic stiffness constant ( | 20.5 ± 0.4 ( | 26.3 ± 2.2* ( | 27.8 ± 1.5* ( | 21.6 ± 1.4** ( |
LV + septum (mg/g body wt) | 1.9 ± 0.2 ( | 2.1 ± 0.03 ( | 2.2 ± 0.07 ( | 1.7 ± 0.1** ( |
RV (mg/g body wt) | 0.53 ± 0.03 ( | 0.41 ± 0.01* ( | 0.43 ± 0.02* ( | 0.44 ± 0.02* ( |
Liver (mg/g body wt) | 26.7 ± 0.6 ( | 28.2 ± 1.4 ( | 29.9 ± 0.95 ( | 23.1 ± 0.02** ( |
Spleen (mg/g body wt) | 2 ± 0.1 ( | 1.8 ± 0.03 ( | 1.68 ± 0.1 ( | 1.75 ± 0.23 ( |
Left and right kidney | 5.15 ± 0.1 ( | 6.3 ± 0.2* ( | 5.94 ± 0.12* ( | 5.13 ± 0.39** ( |
Abdominal fat pads | 401 ± 56 ( | 343 ± 25 ( | 826 ± 62* ( | 339 ± 31** ( |
Plasma malondialdehyde | 26.9 ± 0.7 ( | 29.4 ± 0.5* ( | 32.2 ± 1.2* ( | 28.8 ± 0.6** ( |
Values are mean ± SEM; number of experiments in parentheses. LV, left ventricle; RV, right ventricle; LVIDd, left ventricular internal diameter at diastole; LVPWd, left ventricular posterior wall thickness at diastole. LV mass calculated according to [
Systolic blood pressure increased in CAF + BT-fed rats over the first 4 weeks and was then maintained over the next 12 weeks with mean values of 141 ± 6 mmHg at 8 weeks and 146 ± 4 mmHg at 16 weeks. In contrast, the systolic blood pressure in corn starch-fed rats was unchanged at 115 ± 3 mmHg at 8 weeks and 117 ± 4 mmHg at 16 weeks (Figure
Tail-cuff measurement of systolic blood pressure recorded at 0, 4, 8, 12 and 16 weeks for corn starch (filled square), CAF + BT (filled circle) and CAF + BT + AVE (open circle)-fed rats. *
Post-mortem organ weights showed a selective increase in left ventricular wet weight and kidney weights compared with the right ventricle and other major organs in CAF + BT-fed rats compared with corn starch-fed rats (Table
Picrosirius red staining of left ventricular interstitial collagen deposition in corn starch (16 weeks) (a), CAF + BT (8 weeks) (b), CAF + BT (16 weeks) (c) and CAF + BT + AVE (16 weeks) (d)-treated rats and hematoxylin and eosin staining of infiltrating inflammatory cells of left ventricular interstitial region (magnification,
Vascular responses to noradrenaline were unchanged by CAF + BT feeding. Responses to sodium nitroprusside (endothelium-independent relaxation) were decreased by CAF + BT feeding (Figures
Cumulative concentration-response curves for noradrenaline (a), sodium nitroprusside (b), and acetylcholine (c) in thoracic aortic rings from corn starch (filled square), CAF + BT (filled circle) and CAF + BT + AVE (open circle)-fed rats after 16 weeks of feeding. *
In the DOCA-salt rat model of hypertension, we have shown that treatment with Avemar improved cardiac function, decreased macrophage infiltration resulting in decreased collagen deposition in the ventricular myocardium, reversed an increased stiffness of the left ventricle in the diseased hearts and attenuated oxidative stress measured as plasma malondialdehyde concentrations without changing systolic blood pressure. Our previous studies have shown similar results with inhibitors of the renin-angiotensin system (captopril, candesartan and spironolactone) [
Since the mechanisms for these cardiovascular actions may be an extension of the anti-oxidant, anti-inflammatory and immunomodulatory mechanisms proposed for the anti-cancer actions of Avemar, it is worthwhile considering whether these actions improve cardiovascular function in disease models (Figure
Potential mechanisms for the beneficial effects of Avemar in diet-induced obese rats.
Furthermore, Avemar contains compounds such as benzoquinones and other plant flavonoids, important agents in controlling oxidative stress and cell damage [
Since inflammatory mediators are important in fat deposition [
Similarly, the anti-inflammatory mechanisms useful in treatment of cancer may contribute to the changes in glucose tolerance in the high-carbohydrate/high fat diet rats treated with Avemar [
Other components of Avemar such as the benzoquinones may also be cardioprotective. Benzoquinones have very similar characteristics to vitamins and are anti-oxidant compounds. Coenzyme Q10 (ubiquinone) is a naturally occurring benzoquinone, which may prevent cellular damage during myocardial ischemia and reperfusion by its roles in oxidative phosphorylation and membrane stabilization [
In conclusion, our results show that the fermented wheat germ extract Avemar has a potential role to attenuate the cardiovascular symptoms induced by hypertension, diabetes or the metabolic syndrome while moderating metabolic abnormalities such as glucose tolerance and obesity. Since Avemar is already available in humans as a complementary therapy for cancer, this product could be further evaluated in a clinical setting as an adjunct therapy for preventing cardiovascular and metabolic symptoms.
The University of Queensland; Medimpex Pty Ltd, Mudgeeraba, Australia.