The autonomic nervous system plays critical roles in maintaining homeostasis in humans, directly regulating inflammation by altering the activity of the immune system. The cholinergic anti-inflammatory pathway is a well-studied neuroimmune interaction involving the vagus nerve. CD4-positive T cells expressing β2 adrenergic receptors and macrophages expressing the alpha 7 subunit of the nicotinic acetylcholine receptor in the spleen receive neurotransmitters such as norepinephrine and acetylcholine and are key mediators of the cholinergic anti-inflammatory pathway. Recent studies have demonstrated that vagus nerve stimulation, ultrasound, and restraint stress elicit protective effects against renal ischemia-reperfusion injury. These protective effects are induced primarily via activation of the cholinergic anti-inflammatory pathway. In addition to these immunological roles, nervous systems are directly related to homeostasis of renal physiology. Whole-kidney three-dimensional visualization using the tissue clearing technique CUBIC (clear, unobstructed brain/body imaging cocktails and computational analysis) has illustrated that renal sympathetic nerves are primarily distributed around arteries in the kidneys and denervated after ischemia-reperfusion injury. In contrast, artificial renal sympathetic denervation has a protective effect against kidney disease progression in murine models. Further studies are needed to elucidate how neural networks are involved in progression of kidney disease.
Acetylcholine ; Arteries ; Autonomic Nervous System ; Cholinergic Neurons ; Homeostasis ; Humans ; Immune System ; Inflammation ; Kidney Diseases ; Kidney ; Macrophages ; Nervous System ; Neurotransmitter Agents ; Norepinephrine ; Optogenetics ; Physiology ; Receptors, Adrenergic ; Receptors, Nicotinic ; Reperfusion Injury ; Spleen ; Sympathectomy ; Sympathetic Nervous System ; T-Lymphocytes ; Ultrasonography ; Vagus Nerve ; Vagus Nerve Stimulation

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.
Aged ; Carotid Arteries/diagnostic imaging ; Cerebrovascular Circulation/*physiology ; Dizziness/etiology ; Female ; Hemodynamics/*physiology ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Renal Dialysis ; Risk Factors ; Ultrasonography, Doppler, Duplex

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.
Aged ; Carotid Arteries/diagnostic imaging ; Cerebrovascular Circulation/*physiology ; Dizziness/etiology ; Female ; Hemodynamics/*physiology ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Renal Dialysis ; Risk Factors ; Ultrasonography, Doppler, Duplex

BACKGROUNDThe offspring of women with gestational diabetes mellitus (GDM) are prone to macrosomia. However, birth weight is difficult to be correctly estimated by ultrasound because of fetal asymmetric growth characteristics. This study aimed to investigate the correlations between fetal hemodynamics, fetal growth indices in late pregnancy, and birth weight in GDM.

METHODSA total of 147 women with GDM and 124 normal controls (NC) were enrolled in this study. Fetal hemodynamic indices, including the systolic/diastolic ratio (S/D), resistance index (RI), pulsatility index (PI) of umbilical artery (UA), middle cerebral artery (MCA), and renal artery (RA), were collected. Fetal growth indices, including biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length, were also measured by ultrasound. Birth weight, newborn gender, and maternal clinical data were collected.

RESULTSThe independent samples t-test showed that BPD, HC, and AC were larger in GDM than in NC (P < 0.05). Fetal hemodynamic indices of the UA and MCA were lower (P < 0.05), but those of the RA were higher (P < 0.001) in GDM than in NC. Birth weight was higher in GDM than in NC (P < 0.001). Pearson's correlation analysis showed that hemodynamic indices of the UA were negatively correlated with birth weight, BPD, HC, and AC in both groups (P < 0.05). MCA (S/D, PI, and RI) was negatively correlated with birth weight, HC, and AC in GDM (r = -0.164, -0.206, -0.200, -0.226, -0.189, -0.179, -0.196, -0.177, and - 0.172, respectively, P< 0.05), but there were no correlations in NC (P > 0.05). RA (S/D, PI, and RI) was positively correlated with birth weight in GDM (r = 0.168, 0.207, and 0.184, respectively, P< 0.05), but there were no correlations in NC (P > 0.05).

CONCLUSIONFetal hemodynamic indices in late pregnancy might be helpful for estimating newborn birth weight in women with GDM.

Adult ; Birth Weight ; physiology ; Cerebral Arteries ; physiology ; Diabetes, Gestational ; physiopathology ; Female ; Fetal Development ; physiology ; Hemodynamics ; physiology ; Humans ; Infant, Newborn ; Male ; Pregnancy ; Pregnancy Outcome ; Renal Artery ; physiology ; Ultrasonography, Prenatal ; Umbilical Arteries ; physiology

Quantitative measurement of strain distribution of arterial vessel walls due to pulsatile blood flow within the vascular lumen is valuable for evaluating the elasticity of arterial wall and predicting the evolution of plaques. The present paper shows that the three-dimensional (3D) strain distribution are estimated through uni-directional coupling for 3D vessel and blood models reconstructed from intravascular ultrasound (IVUS) images with the computational. fluid dynamics (CFD) numerical simulation technique. The morphology of vessel wall and plaques as well as strain distribution can be visually displayed with pseudo-color coding.
Arteries ; diagnostic imaging ; physiology ; Elasticity ; Hemodynamics ; Humans ; Imaging, Three-Dimensional ; Pulsatile Flow ; Ultrasonography

OBJECTIVETo evaluate the effect of blood pressure on vascular endothelial function using echo-tracking (ET) technology.

METHODSThirty hypertensive (HP) patients, 30 subjects with high normal blood pressure (HN), and 30 normotensive control (NC) subjects were enrolled in this study. For each subject, conventional two-dimensional ultrasound was performed to measure the intima-media thickness (IMT), and an ET system was utilized to assess the carotid elasticity (Ep, β, AC, AI, and PWVβ).

RESULTSAs the blood pressure increased, IMT, Ep, β, AI, and PWVβ values all increased and AC value decreased. Before excluding the confounding factors, the difference in IMT, Ep, β, AC, AI, and PWVβ values were significant between the 3 groups. After excluding the confounding factors, only PWVβ value was significantly different between HN group and NC group; but between HP and NC group and between HP and HN group, the other parameters still showed significant differences. Systolic blood pressure had significant influences on IMT, Ep, AC, AI, and PWVβ values, diastolic blood pressure significantly affected AI value, and pulse pressure significantly affected Ep and β values.

CONCLUSIONHigh normal blood pressure has no obvious effects on vascular function, and blood pressure is an independent risk factor of vascular endothelial dysfunction only in the stage of early hypertention. In early atherosclerosis, systolic blood pressure is the most significant factors affecting vascular endothelial function, followed by pulse pressure and diastolic blood pressure.

Adult ; Atherosclerosis ; physiopathology ; Blood Pressure ; physiology ; Carotid Arteries ; diagnostic imaging ; Elasticity ; Endothelium, Vascular ; physiopathology ; Female ; Humans ; Hypertension ; complications ; physiopathology ; Male ; Middle Aged ; Ultrasonography

Spectral waveform analysis of blood flow velocity in the major arteries of six healthy, conscious immature micropigs was determined using Doppler ultrasonography. Doppler spectral tracings were recorded from the external iliac artery, femoral artery, and renal arcuate artery. Tracings were also taken from three parts of the common carotid artery and two parts of the abdominal aorta. Spectral Doppler parameters included peak systolic velocity, early diastolic velocity, peak systolic velocity-to-end diastolic velocity ratio, resistive index, and pulsatility index. In addition, the diameter of major arteries and indirect blood pressure were measured. These results from spectral Doppler analysis in major arteries may be useful as reference ranges in the future studies of vascular hemodynamics in immature micropigs.
Animals ; Arteries/physiology/*ultrasonography ; Blood Flow Velocity/physiology/*veterinary ; Male ; Swine ; Swine, Miniature ; Ultrasonography, Doppler, Color/*veterinary

OBJECTIVETo observe the histopathological changes of a novel small-caliber vascular graft after implantation in canine theca interna under scanning electron microscope.

METHODA 3 cm segment of the vascular graft (diameter of 4 mm) was implanted in an end-to-end fashion to bridge the severed carotid artery in 19 healthy dogs. Color Doppler sonography was performed 2 weeks after the operation to observe the patency rate of artificial blood vessel. At 1, 8, 12 and 24 week postimplantation, the arteries (4, 4, 6 and 5, respectively) were collected for optical and scanning electron microscopies after angiography to observe the patency of the arteries.

RESULTSOf the total of 19 arteries, occlusion occurred in 1 at 12 weeks and 1 at 24 weeks. Optical and electron microscopies showed that 1 week after implantation, slight fibroplasias and formation of red thrombus could be seen at the vascular anastomosis without endothelial cell lining. At 8 weeks, the host tissue grew into the lumen of the graft through the pores to form uniform neointima consisting of plenty of collagen fibers, but still without endothelial cells. At 12 weeks, discontinuous endothelial cells were seen to grow on the surface of the neointima. In the middle segment of the vascular graft, immature endothelial cells were found to grow in clusters. The structure of the neointima was loose in comparison with that at the anastomosis, with occasional inflammation cells. Twenty-four weeks after grafting, endothelial cells grew over the entire inner wall of the patent graft, and the surface of the neointima at the anastomosis was lined with continuous endothelial cells.

CONCLUSIONThe vascular graft can be useful for reconstruction of canine carotid artery defect and achieves good endothelialization 24 weeks after implantation.

Animals ; Blood Vessel Prosthesis ; Blood Vessel Prosthesis Implantation ; methods ; Carotid Arteries ; diagnostic imaging ; physiology ; surgery ; Collagen ; metabolism ; Dogs ; Endothelial Cells ; cytology ; metabolism ; ultrastructure ; Microscopy, Electron, Scanning ; Models, Animal ; Time Factors ; Tunica Intima ; cytology ; metabolism ; ultrastructure ; Ultrasonography, Doppler, Color ; Vascular Patency

Focus on the defects of the extraction method of velocity pulsated signals in the velocity spectrum image of pulsed Doppler ultrasounds (such as the limited data, great amount of work and low reproducibility), we combine the earlier research results and the basic rules of the velocity spectrum image, and employing the visual basics plateau, to design and develop a software to extract the velocity signals from the spectrum image automatically. Compare the mean velocity and RNS between the PIV and the PDU resulting from the method, the correlations are r = 0.93 and r = 0.78 respectively. The study reveals the software increase the amount of valid data, decrease the amount of work and increase reproducibility of the signals extraction. The method may be an effective way to analyse the velocity spectrum image of PDU in clinic.
Arteries ; diagnostic imaging ; Blood Flow Velocity ; physiology ; Humans ; Pulsatile Flow ; Signal Processing, Computer-Assisted ; Software ; Ultrasonography, Doppler, Pulsed ; methods

The severity of carotid intima-media thickness (IMT) is an independent predictor of atherosclerosis which causes transient cerebral ischemia, stroke, and coronary events such as myocardial infarction. The IMT consists of intima thickness (IT) and media thickness (MT). However, the Individual clinical significance of IT and MT has not been well studied. We devised a method of measuring IT, MT, and IMT using B-mode ultrasound image processing technique for the diagnosis of atherosclerosis. To inspect the clinical significance of IT, MT, and IMT, one hundred forty-four consecutive patients (mean age; 57 years old, 72 males) were underwent common carotid artery scanning using high-resolution ultrasound. Results showed that, the IT (p<0.05), MT (p<0.05) as well as IMT (p<0.01) of patients with atherosclerotic disease were significantly thicker than that of the patients without atherosclerotic disease. Patients with hypertension showed significantly thicker IT (p<0.01), MT (p<0.001), and IMT (p<0.001). However, only IT was thicker in patients with smoking (p<0.01). The IT (r=0.374, p=0.001), MT (r=0.433, p=0.000), and IMT (r=0.479, p=0.000) showed positive correlation with age. The coefficients of determination (r(2)) were estimated to be 92.4% for IMT and MT, 49.1% for IMT and IT, and 27.4% for IT and MT. This result suggests that the intima layer of the carotid artery has a different physiology with the media layer.
Atherosclerosis ; Carotid Arteries ; Carotid Artery, Common ; Carotid Intima-Media Thickness ; Diagnosis ; Humans ; Hypertension ; Ischemic Attack, Transient ; Middle Aged ; Myocardial Infarction ; Physiology ; Smoke ; Smoking ; Stroke ; Ultrasonography