Abstract TP146: Impaired Acute Collateral Flow Dynamics Experimental Stroke In Type 2 Diabetic Mice

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Yosuke Akamatsu ◽  
Chih C Lee ◽  
Ruikang K Wang ◽  
Jialing Liu
Keyword(s):  
Blood Flow ◽  
Neurologic Deficit ◽  
Flow Dynamics ◽  
Collateral Flow ◽  
Doppler Flowmetry ◽  
Collateral Arteries ◽  
Significant Difference ◽  
Blood Flow Dynamics ◽  
Collateral Vessels

Introduction: Type 2 diabetes mellitus (T2DM) is a major risk factor for stroke, yet it is unclear whether T2DM associated-poor outcome after stroke is related to unfavorable cerebral blood flow dynamics. The current study aimed to investigate the effect of T2DM on acute blood flow dynamics and stroke outcome. Methood: Adult male db/db and db/+ mice (8-9 weeks of age) were subjected to permanent distal middle cerebral artery occlusion (pMCAo). Neurologic deficit was assessed with a 5-point scoring system (0 to 4) and infarction volume was determined at 48 hours after pMCAo by TTC staining. Hemodynamics was evaluated by laser doppler flowmetry. The number of connecting collateral vessels, functional microvascular network morphology, and vessel area density of the ischemic hemisphere were determined by DiI-labeling, and optical coherence tomography (OCT), respectively. Results: db/db mice had a higher baseline blood glucose level (341±39.7 vs. 172±26.5 mg/dl, p <0.01) and a larger infarct volume after pMCAO compared to db/+ mice (69.5±5.4 vs. 51.0±3.1 mm 3 , p <0.01). Neurologic deficit did not differ between groups at 2 hours after pMCAO, but was significantly worse in the db/db at 24 hours after pMCAo compared to db/+ mice (1.9±0.1 vs. 1.4±0.2, p <0.05), correlated with lower rCBF in the core of the MCA territory at 24 and 48 hours (10.9%±1.1 vs. 14.4%±0.8, p <0.05 and 9.5%±1.0 vs. 14.1%±1.2, p =0.01). Ipsilateral functional microvascular density as detected by OCT did not differ between groups at one hour after occlusion but was significantly lower in the db/db mice at 24 hr after pMCAo ( p <0.05). However, we did not observe a significant difference in the number of connecting collateral arteries between groups at 48 hours after pMCAo in this age group. Conclusion: Our results demonstrate that T2DM is associated with lower rCBF and lower density of functional blood vessels during the acute phase of pMCAo, which might in part, contribute to the observed worse outcome in the db/db mice. Ongoing experiments will investigate whether T2DM affects the flow dynamics in individual collateral following MCA occlusion and outward remodeling of the collateral vessels.

Abstract T P83: Strain Differences In Leptomeningeal Collateral Flow Dynamics Correlate With Differences In Stroke Outcome

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Yasuo Nishijima ◽  
Yosuke Akamtsu ◽  
Chih Cheng Lee ◽  
Jialing Liu
Keyword(s):  
Blood Flow ◽  
Acute Phase ◽  
Collateral Circulation ◽  
Artery Occlusion ◽  
Flow Dynamics ◽  
Mouse Strains ◽  
Collateral Flow ◽  
Doppler Flowmetry ◽  
Collateral Arteries ◽  
Retrograde Filling

Introduction: Emerging evidences suggest that the collateral circulation plays a key role in the risk of stroke and the severity of infarction. The current study aimed to investigate the effect of the brain collateral circulation in acute phase of stroke and outcome in two inbred mouse strains that differ markedly in anatomical collateralization. Methods: Male C57BL/6 and Balb/C mice were subjected to permanent unilateral common carotid artery occlusion (CCAO) or temporary distal middle cerebral artery occlusion (dMCAo). Regional cerebral blood flow (rCBF) was assessed by laser doppler flowmetry. In vivo imaging of collateral blood flow and flow velocity was evaluated by doppler optical coherence tomography (DOCT). Infarct size and motor function was assessed at 24 hours and 1 week after dMCAo, respectively. DiI-labeling was used to reveal anastomoses and to determine vessel diameter. Results: The diameters of the ICA and ACA on the ischemic side in both strains markedly decreased at 24 hours after CCAO but recovered at 7 days, although the diameters of ICA, MCA and ACA are larger in the Balb/C compared to the C57BL/6 strain before and after CCAO. Balb/C mice exhibited significantly less leptomeningeal connecting collateral arteries compared to C57BL/6 (0.6±0.3 vs 11.3±0.4, p<0.001), coincided with a larger infarction and worse neurological outcomes after dMCAo compared to C57BL/6. During the acute phase of occlusion of the CCA or MCA, C57BL/6 mice also demonstrated a much more robust retrograde filling of several distal branches of the MCA from ACA compared to Balb/C mice. Conclusion: Our results demonstrate that anatomical insufficiency of the leptomeningeal collateralization is associated with an impaired collateral flow dynamics, resulting in reduced rCBF during the acute phase of MCA stroke, which might in part, contribute to the larger infarction observed in the Balb/C strain.

scholarly journals Investigation of the Pressure and Flow Dynamics during Aspiration Thrombectomy: A Mathematical Modelling Study

2021 ◽  
Vol 2071 (1) ◽  
pp. 012023
Author(s):  
Riccardo Marconi ◽  
Ying Yang ◽  
Shailesh Naire
Keyword(s):  
Blood Flow ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Interventional Procedure ◽  
Blood Clot ◽  
Flow Dynamics ◽  
Collateral Flow ◽  
Aspiration Thrombectomy ◽  
Blood Flow Dynamics

Abstract Aspiration thrombectomy is a life-saving interventional procedure to remove a blood clot from the brain of stroke patients. The pressure and blood flow dynamics during this procedure are crucial in determining the clinical outcomes. A mathematical model based on Hagen-Poiseuille law of fluid flow in a tube is adapted to simulate the pressure and fluid flow characteristics in an in vitro model of an occluded and unoccluded cerebrovascular network that mimics a poor (unilateral) and good (symmetrical) collateral flow within the Circle of Willis. The results show that in the absence of an occlusion, the pressure and pressure drop are higher in the symmetrical network compared to that in the unilateral network. This is due to the additional limb in the symmetrical network that must be supplied, which is absent in the unilateral network. In the presence of an occlusion, the flow reduces in the obstructed vessel, the collateral flow, overall pressure and pressure drop increases in both systems, but is higher for the symmetrical network. The results compare qualitatively with those observed in in vitro studies and with clinical observations. The theoretical framework lays the foundation for more advanced models for the pressure and blood flow dynamics towards clinical applicability.

Abstract 131: Methods Behind Thrombus Size Variability in Murine IVC Ligation Model Revealed: Insights From MRI

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Olivia R Palmer ◽  
Jose A Diaz ◽  
Joan M Greve
Keyword(s):  
Blood Flow ◽  
Flow Direction ◽  
Flow Dynamics ◽  
Variation Coefficient ◽  
Mri Findings ◽  
Venous Flow ◽  
Vein Thrombosis ◽  
Blood Flow Dynamics ◽  
Size Variability ◽  
Collateral Vessels

Objectives: Animal models are key tools for studying deep vein thrombosis (VT). Variation in thrombus size is a current concern that limits the ability to detect small differences between experimental groups. Our objective is to understand the mechanism of this variation. We hypothesized that thrombus size variability results from altered flow dynamics involving venous branches. Using MRI, we investigated the path of blood flow in the murine IVC ligation model. Methods: VT was induced in 11-15 week-old C57BL/6 mice (n=9) via IVC ligation with either interruption of all venous branches (IB), or all branches left open (OB). Mice were imaged by MRI 2 days post ligation to examine IVC patency and/or presence of thrombus. Venous flow was saturated to determine venous branching phenotype and flow direction, which was compared to pre-surgical MRI. Then, axial slices were acquired from the renal to iliac vessels to quantify thrombus volume. Finally, thrombus weight (TW) was quantified at harvest. Results: MRI: Thrombus volumes were larger in IB mice compared to OB mice (38.0 ± 4.6 mm 3 IB vs. 11.3 ± 8.3 mm 3 OB), with greater variability in OB mice (variation coefficient 12% IB vs. 73% OB). Open branches had great impact on reducing TW due to reversed flow direction, increasing thrombus size variability. IB mice showed flow compensation through the vertebral veins and collateral vessels. At harvest: TWs confirmed MRI findings (34.5 ± 3.8 mg IB vs. 15.7 ± 9.8 mg OB; variation coefficient 11% IB vs. 62% OB). The pattern of 2 back branches was observed in all mice, and 1 right branch was the most common phenotype. The OB mouse with the highest TW had 2 side branches, whereas the other OB mice had 1 right branch only. Conclusion: Thrombus size variability increased when branches were not interrupted. Blood flow dynamics detected by MRI were critical for understanding the “flow escape phenomenon” from the IVC that occurs through branches when they are left open. This study supports that the anatomical branching pattern affects blood flow in the IVC. Non-invasive MRI brings to light the important role of venous branches inducing thrombus variability in VT models.

scholarly journals Nephron blood flow dynamics measured by laser speckle contrast imaging

2011 ◽  
Vol 300 (2) ◽  
pp. F319-F329 ◽  
Author(s):  
Niels-Henrik Holstein-Rathlou ◽  
Olga V. Sosnovtseva ◽  
Alexey N. Pavlov ◽  
William A. Cupples ◽  
Charlotte Mehlin Sorensen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Signal Transmission ◽  
Experimental Studies ◽  
Flow Dynamics ◽  
Laser Speckle ◽  
Tubuloglomerular Feedback ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast ◽  
Blood Flow Dynamics

Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50–100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic techniques for extracting the desired data and for examining them for evidence of nephron synchronization. Synchronized TGF oscillations were detected in pairs or triplets of nephrons. The amplitude and the frequency of the oscillations changed with time, as did the patterns of synchronization. Synchronization may take place among nephrons not immediately adjacent on the surface of the kidney.

Muscle Blood-Flow Dynamics at Exercise Onset

2006 ◽  
Vol 38 (10) ◽  
pp. 1811-1818 ◽  
Author(s):  
MICHAEL E. TSCHAKOVSKY ◽  
NATASHA R. SAUNDERS ◽  
KATHERINE A. WEBB ◽  
DENIS E. O'DONNELL
Keyword(s):  
Blood Flow ◽  
Muscle Blood Flow ◽  
Flow Dynamics ◽  
Exercise Onset ◽  
Blood Flow Dynamics

Investigation of blood flow dynamics by NMR angiography

1990 ◽  
Vol 8 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Q. Guo ◽  
L. Friloux ◽  
O. Nalcioglu
Keyword(s):  
Blood Flow ◽  
Flow Dynamics ◽  
Blood Flow Dynamics

scholarly journals Evaluation of the marginal gingival health using laser doppler flowmetry

2006 ◽  
Vol 17 (3) ◽  
pp. 219-222 ◽  
Author(s):  
Hakan Develioglu ◽  
Bülent Kesim ◽  
Aykut Tuncel
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Plaque Index ◽  
Tissue Blood Flow ◽  
Doppler Flowmetry ◽  
Gingival Health ◽  
Significant Difference ◽  
Clinical Indices ◽  
And Control

The purposes of this study were to compare the gingival blood flow (GBF) in test sites (teeth retaining fixed partial dentures) and control sites (contralateral natural teeth) and investigate whether there is any relationship between clinical indices and GBF values. Twelve healthy subjects (6 females and 6 males) aged 20 to 54 years were enrolled this study. The GBF was measured from the middle point of the marginal gingiva in the test and control sites using laser Doppler flowmetry (LDF). Additionally, plaque index, gingival index and probing depth measurements were recorded. Statistically significant difference (p<0.05) was found between the test and control sites for marginal GBF. In contrast, no significant difference (p>0.05) was found between test and control sites with respect to the clinical indices, except for plaque index. The findings of this study suggest that there is a significant relation between resin-bonded fixed partial dentures with margins located subgingivally and marginal GBF. Clinical indices are helpful to collect information about the clinical health status of gingival tissues, but GBF is a good tool to measure gingival tissue blood flow and assess periodontal health. In conclusion, laser Doppler flowmetry can be used together with clinical indices to evaluate the marginal gingival health.

Sign in / Sign up

Export Citation Format

Share Document