Direct Blood Pressure Measurements Research Articles

Short‐term Western Diet Induces Cardiometabolic Syndrome in Female Rats is Associated with Increased Cardiovascular Protein Lysine Acetylation.

The western diet (WD), which is rich in fat, carbohydrates, and refined sugars, is a major contributor to the global epidemic of metabolic syndrome in our modern society. Despite the well‐documented cardioprotection exhibited by the pre‐menopausal female population, studies have indicated that certain stressors may abolish this cardiovascular protection. Studies on the impact of the WD on the cardiometabolic profile of female cohorts remains limited. Lysine acetylation, a reversible posttranslational modification of histone and non‐histone proteins, has been closely associated with metabolic disorders. Based on these factors, we hypothesized that short‐term exposure to the WD alters cardiometabolic parameters in premenopausal rats and alters levels of lysine acetylation in the cardiovascular tissues. Adult female Wistar rats were randomized in two groups: Control Group (n=8) was assigned a regular chow diet and WD Group (n=12) received WD (40% fat, 43% carbohydrates, and 17% protein) for 17 weeks. Results showed that WD group exhibited increased body weight (376 ± 49 vs 305 ± 41g, p<0.05), periabdominal fat content (30 ±11 vs 11 ±2g, p<0.01), % body fat (8.1 ±1.0 vs 3.6 ±0.4%, p<0.01), and serum triglyceride levels (56 ± 13 vs 25 ± 4 mg/dl, p<0.01) compared to controls. Although the WD group exhibited significant increases in glucose intolerance (AUC: 17068.5 ± 730 vs. 13787.67± 814 a.u, p<0.01) and insulin resistance (HOMA‐IR: 5.75 ± 0.9 vs. 3.25 ± 0.62 control, p<0.05), no differences in fasting blood glucose and hemoglobin A1C were found. Using direct arterial blood pressure measurements via carotid artery catheterization, we observed increased systolic blood pressure (146.19 ±9.4 vs 126.22 ± 9.8 mmHg controls, p<0.001), which is contradictory with previous studies. Our vascular reactivity studies revealed that short‐term WD markedly impaired endothelial‐dependent relaxation. Additionally, using DHE staining we found that aortas from the WD group exhibited augmented levels of oxidative stress (3.1‐fold increase vs. control, p<0.001). Strikingly, levels of global lysine acetylation were markedly elevated in the aortas (2.2‐fold increase vs. control, p<0.01) and heart (1.4‐fold increase vs. control, p<0.05) of WD group. Levels of acetyltransferase PCAF were significantly upregulated in the aortas (2.2‐fold increase vs. control, p<0.05). Interestingly, PCAF and deacetylase HDAC9 expression was diminished in hearts from WD group (30% reduction vs. control, p<0.05) and (85% reduction vs. control, p<0.05), respectively. Besides these cardiovascular alterations, the WD also led to the development of non‐alcoholic fatty liver disease (NAFLD) and robust increases in hepatic global lysine acetylation (3.0‐fold increase vs. control, p<0.001). Taken together, our results demonstrated that, even under short‐term exposure, the WD negatively affects the metabolic and cardiovascular parameters of female rats and it is associated with elevated levels of global lysine acetylation in cardiometabolic tissues. This study will be further conducted to identify the specific proteins acetylated in blood vessels and heart from female population under WD regimes.Support or Funding InformationIn‐house Grant NYIT to MACSThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of maternal dyslipidaemia on the cardiorespiratory physiology and biochemical parameters in male rat offspring.

The present study evaluated the effects of maternal dyslipidaemia on blood pressure (BP), cardiorespiratory physiology and biochemical parameters in male offspring. Wistar rat dams were fed either a control (CTL) or a dyslipidaemic (DLP) diet during pregnancy and lactation. After weaning, both CTL and DLP offspring received standard diet. On the 30th and 90th day of life, blood samples were collected for metabolic analyses. Direct measurements of BP, respiratory frequency (RF), tidal volume (VT) and ventilation (VE) under baseline condition, as well as during hypercapnia (7 % CO2) and hypoxia (KCN, 0·04 %), were recorded from awake 90-d-old male offspring. DLP dams exhibited raised serum levels of total cholesterol (TC) (4·0-fold), TAG (2·0-fold), VLDL+LDL (7·7-fold) and reduced HDL-cholesterol (2·4-fold), insulin resistance and hepatic steatosis at the end of lactation. At 30 d of age, the DLP offspring showed an increase in the serum levels of TC (P<0·05) and VLDL+LDL (P<0·05) in comparison with CTL offspring. At 90 d of age, DLP offspring exhibited higher mean arterial pressure (MAP, approximately 34 %). In the spectral analysis, the DLP group showed augmented low-frequency (LF) power and LF:high-frequency (HF) ratio when compared with CTL offspring. In addition, the DLP animals showed a larger delta variation in arterial pressure after administration of the ganglionic blocker (P=0·0003). We also found that cardiorespiratory response to hypercapnia and hypoxia was augmented in DLP offspring. In conclusion, the present data show that maternal dyslipidaemia alters cardiorespiratory physiology and may be a predisposing factor for hypertension at adulthood.

High blood pressure and its relationship to adiposity in a school-aged population: body mass index vs waist circumference.

High blood pressure (HBP) is a major concern in pediatric populations. Adiposity is highly related to HBP in youths; however, whether body mass index (BMI) or waist circumference (WC) is more strongly associated with HBP in this population is unclear. This cross-sectional study, involving schoolchildren between 10 and 17 years of age from public and private schools, assessed direct measurements of BMI, WC and blood pressure. The socioeconomic level, sedentary behavior, physical activity, alcohol consumption and smoking history were obtained through a questionnaire. A Pearson's correlation and linear regression were used. In total, 1011 adolescents with a mean age of 13.1 (+2.3) years were evaluated. The prevalence of overweight/obesity was 27.7%, and the percentage of abdominal obesity was 19.3%. Adolescent boys and girls who had overweight/obesity or abdominal obesity had higher systolic and diastolic blood pressure (BP) values compared with eutrophic adolescents or those without abdominal obesity. In general, both BMI and WC were related to BP, but WC was more strongly correlated with BP than BMI. In conclusion, although both BMI and WC were related to HBP, WC was more strongly associated with blood pressure in young people.

Non-invasive blood pressure measurement in ferrets (Mustela putorius furo) using high definition oscillometry

This study was conducted to validate the use of high definition oscillometry (HDO) for non-invasive blood pressure (NIBP) measurements in ferrets and to establish reference ranges for NIBP in minimally sedated, healthy, young adult ferrets (<4years of age). The bias, limits of agreement and correlation for HDO compared to direct arterial blood pressure (DABP) measurement were established in 14 anaesthetised ferrets. Measurements were performed at the forelimb, hind limb and tail under hypo- (<110mmHg), normo- (110–170mmHg) and hypertensive (>170mmHg) conditions. Although HDO correlated well with DABP (r>0.90), it showed significant proportional bias, whereby HDO generally underestimated DABP with hyper- and normotensive conditions, and overestimated DABP with hypotensive conditions. Measurements obtained from the hind limb showed higher bias than those obtained from the tail or forelimb (P<0.001). Based on the above, and for practical reasons, the tail was selected as the preferred site of cuff placement in ferrets. Subsequently, a cross-over study was performed in 10 ferrets to establish the minimum dose of butorphanol and midazolam needed to successfully obtain NIBP in 100% of cases. Using this dose (0.2mg/kg IM, each), reference intervals for NIBP from 63 healthy, young adult ferrets were established at 95–155mmHg (systolic), 69–109mmHg (mean) and 51–87mmHg (diastolic) arterial pressures.

Validity and reliability of Doppler ultrasonography and direct arterial blood pressure measurements in anaesthetized dogs weighing less than 5 kg

ObjectiveTo assess the validity and reliability of Doppler ultrasonography (DOP) as compared with invasive arterial blood pressure measurements in anaesthetized dogs weighing less than 5 kg. Study designControlled, prospective, clinical study. AnimalsA total of 41 privately owned dogs weighing less than 5 kg. MethodsThe dogs were anaesthetized, and an intra-arterial catheter was placed aseptically in the dorsal pedal artery of the pelvic limb to perform invasive blood pressure (IBP) measurement. The contralateral metatarsal surface of the foot was clipped in order to perform DOP. Both techniques were used to record blood pressure measurements every 5 minutes during surgical procedures. The blood pressure measurements were categorized into two groups: hypotensive [mean arterial pressure (MAP) < 60 mmHg] and normotensive (MAP between 60 and 120 mmHg). A linear mixed model was used to compare the DOP and IBP values. The results were evaluated according to the requirements of the American College of Veterinary Internal Medicine (ACVIM) guidelines for the validation of devices. ResultsDOP provided higher values compared to the systolic arterial blood pressure (SAP) and MAP of IBP measurements. The closest agreement between the two techniques was found for SAP; the bias was 8.8, and limits of agreement (LOA) were –32.9 and 50.4. Similar results were observed when the IBP technique was categorized. The closest agreement was for SAP in animals categorized as normotensive; the bias was 8.2, and LOAs were –32.8 and 49.2. The level of agreement between DOP and IBP did not meet the ACVIM recommendations. Conclusions and clinical relevanceOur results suggest there is poor agreement between DOP and IBP measurements in anaesthetized dogs weighing less than 5 kg. Hence, the use of DOP in these animals could be misleading.

Socioeconomic gradients of cardiovascular risk factors in China and India: results from the China health and retirement longitudinal study and longitudinal aging study in India.

Cardiovascular disease has become a major public health challenge in developing countries. The goal of this study is to compare socioeconomic status (SES) gradients of cardiovascular risk factors (CVRF) both within and between China and India. We used multivariable logistic regression models to examine the associations between SES and CVRF, using data from the China health and retirement longitudinal study and the longitudinal aging study in India. The results showed that, compared to illiteracy, the odds ratios of completing junior high school for high-risk waist circumference were 4.99 (95% confidence interval: 1.77-14.06) among Indian men, 3.42 (95% confidence interval: 1.66-7.05) among Indian women, but 0.74 (95% confidence interval: 0.59-0.92) among Chinese women. Similar patterns were observed between educational attainment and high-risk body mass index, and between education and hypertension, based on self-reported physician diagnosis and direct blood pressure measurements. SES is associated with CVRF in both China and India. However, this relationship showed opposite patterns across two countries, suggesting that this association is not fixed, but is subjective to underlying causal pathways, such as patterns of risky health behaviors and different social and health policies.

Dynamic resistance training improves cardiovascular autonomic variability in male hypertensive rats

The dynamic resistance training (DRT) has been the focus of recent researches; however, few studies evaluated the effects of DRT on hemodynamics of hypertensive subjects. The objective of this study was to evaluate the effects of DRT on blood pressure (BP) and cardiovascular autonomic modulation in spontaneously hypertensive rats. Thus, we used 16 adult males SHR, divided into two groups (n = 8/group): sedentary (SM) and trained (TM). Maximal exercise testing was conducted before and after the training period. The DRT, in moderate intensity (40–60% of the maximal load), was performed in a ladder adapted for rats per 8 weeks. After this period, blood glucose and triglyceride were measured and catheter was inserted in the carotid artery for direct measurement of BP (WINDAQ, 2 KHz). BP and heart rate variability were evaluated in time and frequency domains. At the end of the protocol, there was an improvement in physical capacity in the TM group (TM: 737±39 vs. SM: 476±50 g). Moreover, there were no differences in the weight of left ventricle and soleus muscle; however, the TM group showed an increase in plantar muscle (0.26±0.01 g) when compared to SM group (0.20±0.02 g). There was no difference in heart rate (TM: 350±8 vs. SM: 366±10 bpm) and blood glucose (TM: 88±3 vs. SM: 85±2 mg/dl); however, TM group showed reduced blood triglycerides values (TM: 110±7 vs. SM: 133±4 mg/dl). DTR did not induced reduction in mean, systolic and diastolic BP (mean BP, TM: 186±4 vs. TS: 185±9 mmHg). Despite that, DRT improved cardiac vagal modulation demonstrated by the increase in SD‐IP (TM: 6.61±1.31 vs. SM: 3.68±0.32 ms) and RMSSD (TM: 3.95±0.30 vs. SM: 3.02±0.25 ms). A reduction in BP variance (TM: 33±3 vs. SM: 66±4 mmHg2) and vascular sympathetic modulation (LF‐BP, TM: 6±2 vs. SM: 12±1 mmHg2) were observed in trained group. Additionally, DRT induced an improvement on spontaneous baroreflex (TM: 0.39±0.04 vs. SM: 0.22±0.01 ms/mmHg). We conclude that moderate intensity DRT in male SHR unchanged resting BP, but induced improvement on cardiovascular autonomic variability. These results suggesting a positive role of this approach, associated with aerobic exercise training, on hypertension management.Support or Funding InformationFAPESP 2015/10329‐5, 2015/11223‐6, UNINOVE.

Maternal protein restriction induced-hypertension is associated to oxidative disruption at transcriptional and functional levels in the medulla oblongata.

Maternal protein restriction during pregnancy and lactation predisposes the adult offspring to sympathetic overactivity and arterial hypertension. Although the underlying mechanisms are poorly understood, dysregulation of the oxidative balance has been proposed as a putative trigger of neural-induced hypertension. The aim of the study was to evaluate the association between the oxidative status at transcriptional and functional levels in the medulla oblongata and maternal protein restriction induced-hypertension. Wistar rat dams were fed a control (normal protein; 17% protein) or a low protein ((Lp); 8% protein) diet during pregnancy and lactation, and male offspring was studied at 90days of age. Direct measurements of baseline arterial blood pressure (ABP) and heart rate (HR) were recorded in awakened offspring. In addition, quantitative RT-PCR was used to assess the mRNA expression of superoxide dismutase 1 (SOD1) and 2 (SOD2), catalase (CAT), glutathione peroxidase (GPx), Glutamatergic receptors (Grin1, Gria1 and Grm1) and GABA(A)-receptor-associated protein like 1 (Gabarapl1). Malondialdehyde (MDA) levels, CAT and SOD activities were examined in ventral and dorsal medulla. Lp rats exhibited higher ABP. The mRNA expression levels of SOD2, GPx and Gabarapl1 were down regulated in medullary tissue of Lp rats (P<.05, t test). In addition, we observed that higher MDA levels were associated to decreased SOD (approximately 45%) and CAT (approximately 50%) activities in ventral medulla. Taken together, our data suggest that maternal protein restriction induced-hypertension is associated with medullary oxidative dysfunction at transcriptional level and with impaired antioxidant capacity in the ventral medulla.

Characterization and Antihypertensive Effect of the Complex of (-)-β- pinene in β-cyclodextrin.

This work aimed to characterize and evaluate the antihypertensive effect of the (-)-β-pinene/β-cyclodextrin (βP/β-CD) complex. The complex was prepared through physical mixture and slurry complexation methods and was analyzed through differential scanning calorimetry, thermogravimetry/derivative thermogravimetry, fourier transform infrared spectroscopy, diffraction X-ray, docking and scanning electron microscopy. Normotensive or L-NAME-induced hypertensive rats were used in pharmacological experiments. Mean arterial pressure (MAP) was determined with direct blood pressure measurements from the abdominal aorta. The drugs were orally administrated and their effects were recorded during 48 hours. Vascular effects of βP were evaluated in isolated ring of mesenteric artery. The physicochemical characterization showed βP/β-CD complex formation. In hypertensive rats (MAP = 156±16 mmHg), the complex, but not βP alone, promoted hypotension at 36 and 48 hours after administration (MAP = 124±3 and 110±5 mmHg, respectively). In arterial rings, βP vasorelaxed rings precontracted with phenylephrine (Emax = 105±6%), which was not changed after the removal of the vascular endothelium (Emax = 108±4%), after the pre-contraction with KCl 80 mM (Emax = 107±8%) or S(-)-BayK8644 (Emax = 107±5%), or after incubation with TEA (Emax = 113±4%). Finally, βP inhibited CaCl2- and sodium-orthovanadate-induced contractions. In conclusion, the slurry complexation method was the best among them. Pharmacological results demonstrated that the complex promoted antihypertensive effect. Furthermore, βP induced endothelium- independent vasorelaxation possibly caused by the inhibition of the Ca2+ influx through L-type Ca2+ channel associated to a decrease in calcium sensitivity.

Moderate Intensity Dynamic Resistance Training Induced Cardiovascular Benefits in Female Hypertensive Rats

The dynamic resistance training (DRT) has been the subject of recent studies, however studies using post menopausal women or hypertensive women controlled by pharmacological treatment focusing just on metabolic parameters. Few studies evaluated the chronic effects of this type of training in blood pressure (BP) with direct measurement in untreated hypertensive females. The objective of this study was to evaluate the effects of DRT on BP, physical capacity and muscle weight in spontaneously hypertensive rats. Thus, we used 14 adult females SHR, divided into two groups (n = 7): sedentary females (FS) and trained females (FT). Maximal exercise testing was conducted before and after the training period. The DRT in moderate intensity (40–60% of the maximal load) was performed in a ladder adapted for rats per 8 weeks. After this period, there were blood glucose and triglyceride measurements and we performed cannulation of the carotid artery for direct measurement of BP. Heart tissue and soleus, plantaris and gastrocnemius muscles were weighted. There was improvement in physical capacity in the FT group (Maximum exercise test pre 192.75 ± 12.19 vs. post 471.13 ± 27.23). There were no difference in heart rate (FT: 386.04 ± 11.85 vs. FS: 371.93 ± 12.19 bpm) and metabolic evaluations (blood glucose 103.00 ± 1.94 vs. 102.25 ± 2.78 mg/dl; triglycerides: 112.00 ± 3.71 vs 122.25 ± 8.37 mg/dl, FT vs. FS respectively). Moreover, there were no differences in the weight of the gastrocnemius muscle (p = 0.928) and right ventricle (p = 0.549) between studied groups. DTR induced reduction in mean, systolic and diastolic BP (mean: 164.78 ± 4.96 vs. 179.20 ± 2.61; systolic: 188.97 ± 5.02 vs. 203.33 ± 4.11; diastolic: 142.67 ± 6.80 vs. 156.83 ± 2.29 mmHg, FT vs. FS respectively). Additionally, FT rats presented increased soleus and plantaris muscles and left ventricle weights as compared to FS rats (p &lt;0.05). We conclude that the moderate intensity DRT induced BP reduction associated with cardiac hypertrophy, suggesting a positive role of this approach to hypertension management in females.Support or Funding InformationFAPESP 2015/10329‐5, CNPq 457200/2014‐6, CAPES 88881.062178/2014‐1

'Knowing what matters in diabetes: healthier below 7': results of the campaign's first 10 years (part 1): participants with known type 2 diabetes.

IntroductionDuring the ‘Knowing what matters in diabetes: healthier below 7’ diabetes campaign, more than 30 000 randomly participating individuals underwent an occasional, voluntary diabetes risk check between 2005 and 2014.MethodsThis campaign aimed to inform individuals in Germany about diabetes mellitus and its complications, the established risk factors for development of type 2 diabetes (T2D), their prevalence and management in the real-life population, the quality of risk factor control and actual disease management in participants with a history of established diabetes mellitus [people with diabetes (PWD)]. Besides demographic characteristics (e.g. sex, age) and anamnestic information (antihypertensive treatment, history of elevated plasma glucose levels, genetic disposition), risk factor assessment included BMI, waist circumference, and lifestyle (physical activity, nutritional habits). The requested information was complemented by direct measurements of blood pressure (BP) (routine), plasma glucose, and HbA1c (voluntary). Between 2005 and 2014, more than 31 000 individuals participated in 45 single campaigns in numerous German cities. Here, we report on the results of the subgroup of participants with known diabetes mellitus.ResultsAmong the 26 522 individuals with a completed questionnaire participating in the years 2006–2014, 21 055 participants (79.4%) did not have a history of diabetes and 5098 individuals (19.2%) reported being diagnosed with T2D, 369 (1.4%) with type 1 diabetes. The proportion of participants with T2D increased markedly over the years from 13.3 (2006) to 21.7% (2014). The age group older than 64 years was the largest within this subgroup (67.3%), 48.4% men and 51.6% women. The prevalence of overweight or obesity was found in 78% and 69.2% of the PWD. More than 40% of individuals with T2D had no regular physical exercise and more than 15% had unfavorable nutritional habits. In all, 69.9% of participants with T2D had elevated BP as assessed during the campaign or reported treatment with antihypertensive drugs at any time. On average, almost half of PWD (46.3%) had an HbA1c above 7.0%; a significant trend toward higher values over the 10-year period was observed.ConclusionThe analysis of PWD participating in the ‘Knowing what matters in diabetes: healthier below 7’ campaign showed that despite huge efforts in the past, important aspects for progression and complications of T2D mellitus are still not well controlled. This includes lifestyle habits as well as pharmaceutical treatment. Although the participants in this study cannot be considered a representative sample of the German population and occasional measurements without standardization further limit firm conclusions, the BP, plasma glucose, and HbA1c results indicate that a major proportion of PWD have insufficient metabolic and BP control. The marked increase in the proportion of T2D among all participants over time is consistent with the increasing prevalence of T2D mellitus found in many other countries worldwide in the recent decades. Our findings underline the importance of an optimized therapy for further improvement of disease management in those already diagnosed with this common chronic, progressive disease.

Socioeconomic Gradients of Cardiovascular Risk Factors in China and India: Results from the China Health and Retirement Longitudinal Study and Longitudinal Aging Study in India

Objectives: Cardiovascular disease has become a major public health challenge in developing countries. The goal of this study is to compare socioeconomic status (SES) gradients of cardiovascular risk factors both within and between China and India. Methods: We used data from the China Health and Retirement Longitudinal Study (CAHRLS) and the Longitudinal Aging Study in India (LASI) to analyze the associations between cardiovascular risk factors (waist circumference, body mass index, and hypertension) and SES, particularly education attainment and per capita expenditure. Results: The multivariate logistic regression analyses showed that obesity, defined by either waist circumference or body mass index, was positively correlated with higher education levels in Indian men and women, but inversely associated with education levels among Chinese women. Similar pattern was observed between education attainment and hypertension based on self-reported physician diagnosis and direct blood pressure measurements. Conclusions: SES is associated with cardiovascular risk factors in both China and India. However, the direction of this relationship varies across these two countries, suggesting that this association is not fixed, but is subjective to time and context-dependent causal pathways.

Cardiovascular Adaptation in Response to Chronic Hypoxia in Awake Rats.

To examine how cardiovascular adaptation to chronic hypoxia might evolve, the responses to blood pressure (Pt) and hematocrit (Ht) during long-term systemic exposure to hypoxia were observed in awake rats. Furthermore, the total peripheral vascular resistance (TPR) was estimated using direct measurements of systemic blood pressure (Ps) and blood flow (Qs) in carotid artery based on Darcy's law (TPR=Ps/Qs) to evaluate the remodeling procedure in the microcirculation. BP and Ht under normoxic conditions were kept almost constant, while hypoxic exposure immediately increased Ht to 58% and, thereafter, it remained stable. The TPR values showed no significant differences between hypoxic and normoxic conditions. These results suggest that effects of high viscosity caused by increasing Ht on peripheral vascular resistance can be compensated by inducing microvascular remodeling with the arteriolar dilation and capillary angiogenesis.

Comparison of blood pressure measurements of anesthetized dogs obtained noninvasively with a cylindrical blood pressure cuff and an anatomically modified conical blood pressure cuff.

To compare blood pressure measured noninvasively with an oscillometric device that involved use of a novel conical cuff and a traditional cylindrical blood pressure cuff. 17 adult hound-type dogs. Dogs were anesthetized, and a 20-gauge, 1.5-inch catheter was inserted in the median sacral artery. The catheter was attached to a pressure transducer via fluid-filled noncompliant tubing, and direct blood pressure was recorded with a multifunction monitor. A specially fabricated conical cuff was placed on the antebrachium. Four sets of direct and indirect blood pressure measurements were simultaneously collected every 2 minutes. Four sets of measurements were then obtained by use of a cylindrical cuff. The cylindrical cuff met American College of Veterinary Internal Medicine consensus guidelines for validation of indirect blood pressure measurements for mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), and diastolic arterial blood pressure (DAP). The conical cuff met the consensus guidelines for difference of paired measurements, SD, and percentages of measurements within 10 and 20 mm Hg of the value for the reference method, but it failed a correlation analysis. In addition, although bias for the conical cuff was less than that for the cylindrical cuff for SAP, MAP, and DAP measurements, the limits of agreement for the conical cuff were wider than those for the cylindrical cuff for SAP and MAP measurements. On the basis of results of this study, use of a conical cuff for oscillometric blood pressure measurement cannot be recommended.

Maternal Protein Restriction Increases Respiratory and Sympathetic Activities and Sensitizes Peripheral Chemoreflex in Male Rat Offspring1–3

Background: Maternal protein restriction in rats increases the risk of adult offspring arterial hypertension through unknown mechanisms.Objectives: The aims of the study were to evaluate the effects of a low-protein (LP) diet during pregnancy and lactation on baseline sympathetic and respiratory activities and peripheral chemoreflex sensitivity in the rat offspring.Methods: Wistar rat dams were fed a control [normal-protein (NP); 17% protein] or an LP (8% protein) diet during pregnancy and lactation, and their male offspring were studied at 30 d of age. Direct measurements of baseline arterial blood pressure (ABP), heart rate (HR), and respiratory frequency (Rf) as well as peripheral chemoreflex activation (potassium cyanide: 0.04%) were recorded in pups while they were awake. In addition, recordings of the phrenic nerve (PN) and thoracic sympathetic nerve (tSN) activities were obtained from the in situ preparations. Hypoxia-inducible factor 1α (HIF-1α) expression was also evaluated in carotid bifurcation through a Western blotting assay.Results: At 30 d of age, unanesthetized LP rats exhibited enhanced resting Rf (P = 0.001) and similar ABP and HR compared with the NP rats. Despite their similar baseline ABP values, LP rats exhibited augmented low-frequency variability (∼91%;P = 0.01). In addition, the unanesthetized LP rats showed enhanced pressor (P = 0.01) and tachypnoeic (P = 0.03) responses to peripheral chemoreflex activation. The LP rats displayed elevated baseline tSN activity (∼86%;P = 0.02) and PN burst frequency (45%;P = 0.01) and amplitude (53%;P = 0.001) as well as augmented sympathetic (P = 0.01) and phrenic (P = 0.04) excitatory responses to peripheral chemoreflex activation compared with the NP group. Furthermore, LP rats showed an increase of ∼100% in HIF-1α protein density in carotid bifurcation compared with NP rats.Conclusion: Sympathetic-respiratory overactivity and amplified peripheral chemoreceptor responses, potentially through HIF-1α–dependent mechanisms, precede the onset of hypertension in juvenile rats exposed to protein undernutrition during gestation and lactation.

Agreement of high definition oscillometry with direct arterial blood pressure measurement at different blood pressure ranges in horses under general anaesthesia

ObjectiveTo determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia. Study designExperimental study. AnimalsSeven healthy warmblood horses, aged 3–11 years, weighing 470–565 kg. MethodsMeasurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg−1 minute−1) over ten minutes followed by norepinephrine (0.1 mg kg−1 IV) and low pressures by increasing the inspired fraction of isoflurane and administration of nitroglycerine (0.05 mg kg−1 IV). For analysis three pressure levels were determined: high (MAP>110 mmHg), normal (60 mmHg<MAP<110 mmHg) and low (MAP< 60 mmHg). Bland-Altman analysis was used for comparison between non-invasive and invasive measurements. ResultsA total of 245 paired measurements of systolic (SAP), mean (MAP) and diastolic (DAP) pressures were obtained. The HDO device underestimated blood pressure at hypertensive and normotensive levels and overestimated blood pressure at hypotensive levels. Best agreement was obtained for SAP and MAP within normotensive limits. At normotension, bias ± standard deviation for SAP, MAP and DAP were 0.1 ± 19.4 mmHg, 0.5 ± 14.0, 4.7 ± 15.6, respectively. At high pressure levels bias and SD were 26.1 ± 37.3 (SAP), 4.2 ± 19.4 (MAP), 1.5 ± 16.8 (DAP) and at low pressures -20.0 ± 20.9 (SAP), -11.4 ± 19.6 (MAP), -4.7 ± 20.1 (DAP), with HDO measurements at a MAP <50 mmHg often failing. Conclusion and clinical relevanceGood agreement with invasive arterial blood pressures was obtained with HDO at normotensive levels in horses. At high and low pressure ranges HDO was unreliable. Therefore, if haemodynamic instability is expected, invasive measurement remains preferable.

Renal shock wave lithotripsy may be a risk factor for early-onset hypertension in metabolic syndrome: A pilot study in a porcine model

A pilot study was conducted to assess whether extracorporeal shock wave lithotripsy (SWL) treatment of the kidney influences the onset and severity of metabolic syndrome (MetS)—a cluster of conditions that includes central obesity, insulin resistance, impaired glucose tolerance, dyslipidemia, and hypertension. Methods: Three-month-old juvenile female Ossabaw miniature pigs were treated with either SWL (2000 SWs, 24 kV, 120 SWs/min using the HM3 lithotripter; n = 2) or sham-SWL (no SWs; n = 2). SWs were targeted to the upper pole of the left kidney so as to model treatment that would also expose the pancreas—an organ involved in blood glucose homeostasis—to SWs. The pigs were then instrumented for direct measurement of arterial blood pressure via implanted radiotelemetry devices, and later fed a hypercaloric atherogenic diet for ~7 months to induce MetS. The development of MetS was assessed from intravenous glucose tolerance tests. Results: The progression and severity of MetS were similar in the sham-treated and SWL-treated groups. The only exception was arterial blood pressure, which remained relatively constant in the sham-treated pigs and rose toward hypertensive levels in SW-treated pigs. Conclusions. These preliminary results suggest that renal SWL appears to be a risk factor for early-onset hypertension in MetS.

Noninvasive Hemodynamic Monitoring Devices

Noninvasive Hemodynamic Monitoring Devices

Comparison of indirect and direct blood pressure measurements in baboons during ketamine anaesthesia

The aim of this study was to assess agreement between different methods of blood pressure measurement in anaesthetised baboons. Systolic and diastolic blood pressure (SBP and DBP) were measured in anaesthetised baboons using intra-arterial radiotelemetry, automated oscillometry and mercury sphygmomanometry. Correlation between the different methods was assessed. The correlation between intra-arterial radiotelemetry and automated oscillometry was 0.9 (P<0.001) for SBP and 0.9 (P<0.001) for DBP. Between-method differences were -4.4±7.2mm Hg for SBP and -3.4±7.1mm Hg for DBP. For automated oscillometry vs. mercury sphygmomanometry, correlation was 0.4 for both SBP (P<0.001) and DBP (P<0.001). Between-method differences were 7.9±12.7mm Hg for SBP and 7.3±12.6mm Hg for DBP. Our study demonstrates that automated oscillometry may be an appropriate alternative to telemetry for measuring blood pressure in anaesthetised baboons.

The Cardiovascular Effects of Sevoflurane and Isoflurane After Premedication of Healthy Dogs Undergoing Elective Surgery

Sevoflurane and isoflurane are commonly used in veterinary anesthesia. The objective of this prospective, randomized, open-label clinical study was to compare the cardiovascular effects of sevoflurane and isoflurane via direct arterial blood pressure measurements and the lithium dilution cardiac output (LDCO) on premedicated healthy dogs undergoing elective tibial plateau leveling osteotomy (TPLO). Nineteen client-owned dogs were included. All dogs were premedicated with hydromorphone (0.05 mg/kg IV and glycopyrrolate 0.01 mg/kg subcutaneously). Ten dogs were anesthetized with sevoflurane and nine dogs were anesthetized with isoflurane. Eighteen dogs were instrumented with a dorsal pedal arterial catheter, and one dog had a femoral arterial catheter. All dogs had continuous, direct systolic (SAP), diastolic (DAP), and mean arterial (MAP) blood pressure readings as well as heart rate (HR), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI), stroke volume variation (SVV), and pulse pressure variation (PPV) recorded q 5 min during the surgical procedure. There was no significant statistical difference in all parameters between the sevoflurane and isoflurane treatment groups. Both sevoflurane and isoflurane inhalant anesthetics appear to have similar hemodynamic effects when used as part of a multimodal anesthetic protocol in premedicated healthy dogs undergoing an elective surgical procedure.