scholarly journals Diabetic mice have retinal and choroidal blood flow deficits and electroretinogram deficits with impaired responses to hypercapnia

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259505
Author(s):  
Eric R. Muir ◽  
Divya Narayanan ◽  
Saurav B. Chandra ◽  
Nikolay P. Akimov ◽  
Jeong-Hyeon Sohn ◽  
...  
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Oscillatory Potentials ◽  
Diabetic Mouse ◽  
Retinal Blood Flow ◽  
Diabetic Mice ◽  
Neuronal Function ◽  
Choroidal Blood Flow ◽  
Significant Group ◽  
Diabetic Retina

Purpose The purpose of this study was to investigate neuronal and vascular functional deficits in the retina and their association in a diabetic mouse model. We measured electroretinography (ERG) responses and choroidal and retinal blood flow (ChBF, RBF) with magnetic resonance imaging (MRI) in healthy and diabetic mice under basal conditions and under hypercapnic challenge. Methods Ins2Akita diabetic (Diab, n = 8) and age-matched, wild-type C57BL/6J mice (Ctrl, n = 8) were studied under room air and moderate hypercapnia (5% CO2). Dark-adapted ERG a-wave, b-wave, and oscillatory potentials (OPs) were measured for a series of flashes. Regional ChBF and RBF under air and hypercapnia were measured using MRI in the same mice. Results Under room air, Diab mice had compromised ERG b-wave and OPs (e.g., b-wave amplitude was 422.2±10.7 μV in Diab vs. 600.1±13.9 μV in Ctrl, p < 0.001). Under hypercapnia, OPs and b-wave amplitudes were significantly reduced in Diab (OPs by 30.3±3.0% in Diab vs. -3.0±3.6% in Ctrl, b-wave by 17.9±1.4% in Diab vs. 1.3±0.5% in Ctrl). Both ChBF and RBF had significant differences in regional blood flow, with Diab mice having substantially lower blood flow in the nasal region (ChBF was 5.4±1.0 ml/g/min in Diab vs. 8.6±1.0 ml/g/min in Ctrl, RBF was 0.91±0.10 ml/g/min in Diab vs. 1.52±0.24 ml/g/min in Ctrl). Under hypercapnia, ChBF increased in both Ctrl and Diab without significant group difference (31±7% in Diab vs. 17±7% in Ctrl, p > 0.05), but an increase in RBF was not detected for either group. Conclusions Inner retinal neuronal function and both retinal and choroidal blood flow were impaired in Diab mice. Hypercapnia further compromised inner retinal neuronal function in diabetes, while the blood flow response was not affected, suggesting that the diabetic retina has difficulty adapting to metabolic challenges due to factors other than impaired blood flow regulation.

scholarly journals Impaired Choroidal Blood Flow in Adolescents with Essential Arterial Hypertension

2019 ◽  
Vol 4 (4) ◽  
pp. 91-95
Author(s):  
Yu. N. Savina ◽  
S. I. Zhukova ◽  
A. V. Korolenko ◽  
D. A. Averyanov
Keyword(s):  
Blood Flow ◽  
Arterial Hypertension ◽  
Children And Adolescents ◽  
Ganglion Cells ◽  
Color Doppler ◽  
Oscillatory Potentials ◽  
Choroidal Blood Flow ◽  
Choroidal Ischemia ◽  
Essential Arterial Hypertension ◽  
Few Data

Arterial hypertension is a problem not only for adults, but also for children, but there are very few data on changes in the organ of vision under the influence of an elevated level of blood pressure in children.The aim of the work is to identify disturbances of the choroidal blood flow in children and adolescents with essential arterial hypertension.Methods. Fifty patients with essential arterial hypertension were examined. The age of patients ranged from 10 to 17 years, the duration of the disease ranged from 2 months to 8 years. All patients underwent color Doppler mapping of the orbital vessels, registration of the oscillatory potentials of the ERG.Results. It was revealed that increased arterial pressure causes retinal and choroidal ischemia, which is accompanied primarily by impaired blood flow in the orbital vessels and is reflected in a decrease in the amplitude and deformation of the peaks of the ERG oscillatory potentials.Conclusion. Hypertension causes and supports retinal and choroidal ischemia, which is accompanied primarily by impaired blood flow in the orbital vessels, functional depression of photoreceptors, ganglion cells and neuroglia of the retina, aggravating the identified changes as the experience of essential hypertension increases. A marker of chorioretinal ischemia is amplitude depression, a change in the shape of the teeth of the oscillatory potentials of the ERG, which indicates a decrease in the functional activity of the retinal ganglion complex.That is, these changes can be considered as a predictor of hypertensive angioretinopathy in children and adolescents with essential arterial hypertension.

scholarly journals 2126 Optimizing a technique for visualizing retinal and choroidal blood flow noninvasively

2018 ◽  
Vol 2 (S1) ◽  
pp. 22-23
Author(s):  
Paras Vora ◽  
Nicholas Bell ◽  
Romulo Albuquerque ◽  
Jooyoung Cho ◽  
Gregory Botzet
Keyword(s):  
New York ◽  
Blood Flow ◽  
Diabetic Retinopathy ◽  
Digital Video ◽  
Human Subjects ◽  
Sampling Rate ◽  
Retinal Blood Flow ◽  
Current Standard ◽  
Choroidal Blood Flow ◽  
Video Cameras

OBJECTIVES/SPECIFIC AIMS: Diabetic retinopathy is an increasingly prevalent disease, difficult to screen for across the globe. We have developed and began optimizing an innovative technique to visualize and quantify retinal blood flow, to elucidate the role of the choroid in retinal pathologies such as diabetic retinopathy or choroidopathy. METHODS/STUDY POPULATION: Preliminary retinal was obtained from a surgical retina video library (Truvision, Goleta, CA, USA). Videos of different organs were recorded while vessels were occluded via a blood pressure cuff, using consumer-grade digital video cameras (NEX-5T, a7sii; Sony, New York, NY, USA). All other retinal videos were taken using a fundus camera (50×; Topcon, Oxland, NJ, USA) modified to support the above digital video cameras. All videos were processed using experimental software (MATLAB, Mathworks, Natick, MA, USA). RESULTS/ANTICIPATED RESULTS: Video imaging of the retina was optimized for lighting conditions and software requirements. Parameters were defined for the software imaging pipeline, such as frequency range of interest, sampling rate, and noise minimization. Software was developed to stabilize frames, accounting for eye saccades. Use of a biosensor enabled accurate measurement of pulse waveform, increasing signal-to-noise ratio. The optimal light requirements were determined such that adequate exposure of the retina is reproducible yet still comfortable for use in human subjects. DISCUSSION/SIGNIFICANCE OF IMPACT: This novel technique allows for an inexpensive, noninvasive, and reproducible ocular blood flow imaging platform. By optimizing this technique, we can proceed with our future plans for a pilot study to compare our imaging technique with the current standard, paving the way for future clinical studies.

scholarly journals Central Serous Chorioretinopathy from the Point of View of OCT-Angiography. Part 1. Chorioretinal Blood Flow Changes

2018 ◽  
Vol 15 (3) ◽  
pp. 294-302
Author(s):  
A. G. Shchuko ◽  
S. I. Zhukova ◽  
T. N. Iureva ◽  
A. N. Zlobina
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Central Serous Chorioretinopathy ◽  
Regional Blood Flow ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Vascular Wall ◽  
Optical Coherence ◽  
Choroidal Blood Flow ◽  
Large Vessels

Numerous recent studies indicate that the key mechanism for the development of central serous chorioretinopathy (CSR) is damage to retinal pigment epithelium (RPE). At the same time, the reports appeared in recent years indicate that an equally important link in pathogenesis is the disturbances of the choroidal blood flow. Thus, the introduction into clinical practice of optical coherence tomography in the angiography (OCTA) mode made it possible to visualize the retinal and choroidal vessels taking into account their segmentation, which opens up prospects for studying chorioretinal blood flow in the CSR.Purpose:to reveal the regularities of the change in the choroidal blood flow in patients with SCR according to the OCTA data, to assess their informativeness and role in the pathogenesis of the disease.Patients and methods:26 patients with SCR aged 35–54 years were examined. To assess the chorioretinal blood flow, optical coherence tomography of the retina is included in the angiography mode in the scope of the diagnostic examination.Results and discussion:It has been revealed that the number of large vessels in the immediate vicinity of the RPE is increasing in SCR, i.e. the vessels move towards the retina in the direction of the least resistance. Disturbance of the hierarchy of the vasculature is an important fact, allowing to speak about pronounced hemodynamic disorders. Disturbance of the topography of large-caliber vessels is accompanied by the formation of a characteristic vascular pattern. The revealed predominance of the reticular pattern of large vessels in patients with CSR is more likely due to the presence of a significant number of bifurcations and anastomoses, as well as an increase in the proportion of crossed vessels. This may be accompanied by an increase in total vascular resistance. Consequently, the hydraulic resistance can increase at these sites, a turbulent blood flow occurs and the permeability of the vascular wall increases. Correspondence between changes in RPE and choriocapillaries was established. Taking into account that the RPE detachments from 450 to 780 (on average 515 ± 72.3) μm, revealed in the projection of the altered choriocapillaries, have comparable sizes with the value of one vascular lobe (515 × 450) μm, one can speak of a local lesion of choriocapillaries and RPE within one arteriocentric lobules.Conclusions:The revealed changes in regional blood flow are progressive and can be used as classification and prognostic criteria for choroidal dysfunction.

Major role for neuronal NO synthase in curtailing choroidal blood flow autoregulation in newborn pig

2001 ◽  
Vol 91 (4) ◽  
pp. 1655-1662 ◽  
Author(s):  
P. Hardy ◽  
D. Lamireau ◽  
X. Hou ◽  
I. Dumont ◽  
D. Abran ◽  
...  
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Narrow Range ◽  
No Synthase ◽  
Retinal Blood Flow ◽  
Choroidal Blood Flow ◽  
Neuronal No Synthase ◽  
Nos Inhibitors ◽  
Newborn Pigs ◽  
Hemodynamic Function

We examined whether nitric oxide (NO) generated from neuronal NO synthase (nNOS) contributes to the reduced ability of the newborn to autoregulate retinal blood flow (RBF) and choroidal blood flow (ChBF) during acute rises in perfusion pressure. In newborn pigs (1–2 days old), RBF (measured by microsphere) is autoregulated over a narrow range of perfusion pressure, whereas ChBF is not autoregulated. N G-nitro-l-arginine methyl ester (l-NAME) or specific nNOS inhibitors 7-nitroindazole, 3-bromo-7-nitroindazole, and 1-(2-trifluoromethyl-phenyl)imidazole as well as ganglionic blocker hexamethonium, unveiled a ChBF autoregulation as observed in juvenile (4- to 6-wk old) animals, whereas autoregulation of RBF in the newborn was only enhanced byl-NAME. All NOS inhibitors and hexamethonium prevented the hypertension-induced increase in NO mediator cGMP in the choroid. nNOS mRNA expression and activity were three- to fourfold higher in the choroid of newborn pigs than in tissues of juvenile pigs. It is concluded that increased production of NO from nNOS curtails ChBF autoregulation in the newborn and suggests a role for the autonomic nervous system in this important hemodynamic function, whereas, for RBF autoregulation, endothelial NOS seems to exert a more important contribution in limiting autoregulation.

scholarly journals ET-1 plasma levels and ocular blood flow in retinitis pigmentosaThis article is one of a selection of papers published in the two-part special issue entitled 20 Years of Endothelin Research.

2010 ◽  
Vol 88 (6) ◽  
pp. 630-635 ◽  
Author(s):  
Mauro Cellini ◽  
Ernesto Strobbe ◽  
Corrado Gizzi ◽  
Emilio C. Campos
Keyword(s):  
Blood Flow ◽  
Plasma Levels ◽  
Color Doppler ◽  
Cold Pressor Test ◽  
Peak Systolic Velocity ◽  
Cold Pressor ◽  
Retinal Blood Flow ◽  
Doppler Imaging ◽  
Choroidal Blood Flow ◽  
Doppler Flowmetry

Retinitis pigmentosa (RP) is an inherited retinal disorder clinically characterized by a pale, waxy optic nerve head, attenuated retinal blood vessels, and bone spicule pigment in the retina. Hemodynamic studies have demonstrated that RP is associated with a reduction in the retinal and choroidal blood flow. Retinal hemodynamic impairment is also present in early stages of RP, and various hypotheses have been advanced as to the cause. The authors studied 20 patients, 12 males and 8 females, aged 26–42 years (mean 35.1 years) and affected by simplex RP. The patients had a visual acuity of 0.9 ± 0.1, visual field mean defect of –6.52 ± 3.58 dB, and b-wave electroretinogram amplitude of 260.08 ± 8.24 µV. An increase in plasma levels of endothelin-1 (ET-1) was found: 1.910 ± 0.317 pg/mL versus 1.180 ± 0.210 pg/mL in non-RP controls (p < 0.02). Moreover both an ocular and systemic vascular impairment was detected by means of color Doppler imaging and laser Doppler flowmetry performed during a cold pressor test. We found a correlation between the increase of ET-1 plasma levels in RP and the decrease of peak systolic velocity in the ophthalmic artery (p < 0.03) and in the posterior ciliary arteries (p < 0.006). It is thought that an increase of ET-1 and retinal oxygen levels in RP could lead to vasoconstriction and a decrease of the retinal blood flow, worsening the abiotrophic process.

scholarly journals Free fatty acids/triglycerides increase ocular and subcutaneous blood flow

2001 ◽  
Vol 280 (1) ◽  
pp. R56-R61 ◽  
Author(s):  
Kaija Polak ◽  
Leopold Schmetterer ◽  
Alexandra Luksch ◽  
Susanna Gruber ◽  
Elzbieta Polska ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acids ◽  
Blood Flow ◽  
Free Fatty Acids ◽  
Retinal Blood Flow ◽  
Constant Infusion ◽  
Pressure Amplitude ◽  
Choroidal Blood Flow ◽  
Doppler Flowmetry ◽  
Subcutaneous Blood Flow

Elevated plasma free fatty acids (FFA) induce skeletal muscle insulin resistance and impair endothelial function. The aim of this study was to characterize the acute hemodynamic effects of FFA in the eye and skin. A triglyceride (Intralipid 20%, 1.5 ml/min)/heparin (bolus: 200 IU; constant infusion rate: 0.2 IU · kg−1· min−1) emulsion or placebo was administered to 10 healthy subjects. Measurements of pulsatile choroidal blood flow with laser interferometry, retinal blood flow with the blue field entoptic technique, peak systolic and end diastolic blood velocity (PSV, EDV) in the ophthalmic artery with Doppler sonography, and subcutaneous blood flow with laser Doppler flowmetry were performed during an euglycemic somatostatin-insulin clamp over 405 min. Plasma FFA/triglyceride elevation induced a rise in pulsatile choroidal blood flow by 25 ± 3% ( P < 0.001) and in retinal blood flow by 60 ± 23% ( P= 0.0125). PSV increased by 27 ± 8% ( P = 0.001), whereas EDV was not affected. Skin blood flow increased by 149 ± 38% ( P = 0.001). Mean blood pressure and pulse rate remained unchanged, whereas pulse pressure amplitude increased by 17 ± 5% ( P = 0.019). Infusion of heparin alone had no hemodynamic effect in the eye or skin. In conclusion, FFA/triglyceride elevation increases subcutaneous and ocular blood flow with a more pronounced effect in the retina than in the choroid, which may play a role for early changes of ocular perfusion in the insulin resistance syndrome.

scholarly journals Blue flicker modifies the subfoveal choroidal blood flow in the human eye

2005 ◽  
Vol 289 (2) ◽  
pp. H683-H691 ◽  
Author(s):  
John V. Lovasik ◽  
Hélène Kergoat ◽  
Marcelo A. Wajszilber
Keyword(s):  
Blood Flow ◽  
Blue Light ◽  
Near Infrared ◽  
Short Wave ◽  
Retinal Blood Flow ◽  
Differential Distribution ◽  
Choroidal Blood Flow ◽  
Relative Response ◽  
Retinal Photoreceptor ◽  
Stimulation Group

The objective of the present study was to reveal an interaction between choroidal blood flow (ChBF) and light-induced photoreceptor activity, a physiological coupling that has been already demonstrated for retinal blood flow but rejected for ChBF. Ten healthy adults volunteered for this study. A real-time recording near-infrared laser-Doppler flowmeter was used to quantify the subfoveal ChBF while the luminance of blue flicker between 1 and 64 Hz was first increased and then decreased by 4.0 log units in 1.0-log unit steps between 0.0375 and 375 cd/m2. In separate testing, flash electroretinograms (ERGs) provided electrophysiological indexes of the relative response of short-wave cones (s-cones) and rods to blue light stimulation. Group-averaged, normalized ChBF measurements revealed that it was modulated by ∼9% by flicker frequency. Increasing the blue flicker luminance from low to high attenuated the subfoveal ChBF, volume, and velocity by ∼32%, ∼30%, and ∼5%, respectively. Decreasing the luminance from high to low over the same range had no effect on the subfoveal choroidal hemodynamics. The markedly different effects of reversed directions of change in blue flicker luminance on the subfoveal ChBF were linked to transitions between rod-dominated and s-cone-dominated retinal responses. Collectively, these findings indicate that the blue light-induced photoreceptor response is associated with a differential distribution of the ChBF across the ocular fundus according to the degree and type of retinal photoreceptor stimulated.

Assessment of the incorporation of revascularized fibula grafts used for mandibular reconstruction with F-18-PET

2001 ◽  
Vol 40 (02) ◽  
pp. 51-58 ◽  
Author(s):  
H. Schliephake ◽  
van den Hoff ◽  
W. H. Knapp ◽  
G. Berding
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Venous Blood ◽  
Mandibular Reconstruction ◽  
Reference Region ◽  
Osteoblastic Activity ◽  
Non Union ◽  
Range Of Values ◽  
Measured Input

Summary Aim: Determination of the range of regional blood flow and fluoride influx during normal incorporation of revascularized fibula grafts used for mandibular reconstruction. Evaluation, if healing complications are preceded by typical deviations of these parameters from the normal range. Assessment of the potential influence of using “scaled population-derived” instead of “individually measured” input functions in quantitative analysis. Methods: Dynamic F-l 8-PET images and arterialized venous blood samples were obtained in 11 patients early and late after surgery. Based on kinetic modeling regional blood flow (K1) and fluoride influx (Kmlf) were determined. Results: In uncomplicated cases, early postoperative graft K1 - but not Kmlf -exceeded that of vertebrae as reference region. Kmn values obtained in graft necrosis (n = 2) were below the ranges of values observed in uncomplicated healing (0.01 13-0.0745 ml/min/ml) as well as that of the reference region (0.0154-0.0748). Knf values in mobile non-union were in the lower range - and those in rigid non-union in the upper range of values obtained in stable union (0.021 1-0.0694). If scaled population-derived instead of measured input functions were used for quantification, mean deviations of 23 ± 17% in K1 and 12 ± 16% in Kmlf were observed. Conclusions: Normal healing of predominantly cortical bone transplants is characterized by relatively low osteoblastic activity together with increased perfusion. It may be anticipated that transplant necrosis can be identified by showing markedly reduced F− influx. In case that measured input functions are not available, quantification with scaled population-derived input functions is appropriate if expected differences in quantitative parameters exceed 70%.

Basic Ideas and Principles for Quantifying Regional Blood Flow with Nuclear Medical Techniques

1996 ◽  
Vol 35 (05) ◽  
pp. 181-185 ◽  
Author(s):  
H. Herzog
Keyword(s):  
Blood Flow ◽  
Nuclear Medicine ◽  
Regional Blood Flow ◽  
Visual Presentation ◽  
Regional Cerebral Blood ◽  
Basic Principles ◽  
Parametric Images ◽  
Major Application ◽  
Basic Ideas ◽  
The Brain

SummaryThe measurement of blood flow in various organs and its visual presentation in parametric images is a major application in nuclear medicine. The purpose of this paper is to summarize the most important nuclear medicine procedures used to quantify regional blood flow. Starting with the first concepts introduced by Fick and later by Kety-Schmidt the basic principles of measuring global and regional cerebral blood are discussed and their relationships are explained. Different applications and modifications realized first in PET- and later in SPECT-studies of the brain and other organs are described. The permeability and the extraction of the different radiopharmaceuticals are considered. Finally some important instrumental implications are compared.

Sign in / Sign up

Export Citation Format

Share Document