bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 51: Effects of Human Immunodeficiency Virus-1 gp120 Viral Proteins on Endothelial Senescence and microRNA Expression
Authors: Hijmans Jamie , Stockelman Kelly , Reiakvam Whitney , Levy Ma’ayan , Bruster Lillian , Goldthwaite Zoë , Bammert Tyler , Greiner Jared , Connick Elizabeth , DeSouza Christopher
Published: July 2021

Human immunodeficiency virus (HIV)-1 is associated with profound endothelial cell damage and dysfunction. HIV-1 envelope glycoprotein 120 (gp120) is a toxic viral protein released from infected cells and promotes endothelial cell dysfunction. Endothelial cell senescence is a key factor underlying endothelial dysfunction and, in turn, vascular disease risk. It is now clear that microRNAs (miRs) play a pivotal role in regulating cellular senescence. The aim of this study was to determine whether gp120 induces endothelial cell senescence; and if so, whether the cellular expression of senescence-related miRs (mir-34a, -146a and -217) are adversely affected by gp120. Cultured HAECs (3
rd
passage) were plated at a density of 5.0x10
5
cells/condition. Cells were treated with media alone or media containing gp120: either
lav
gp120 (X4; 100ng/mL) or
Bal
gp120 (R5; 100ng/mL) for 24 h. Thereafter, cells were stained for senescence-associated β-galactosidase (β-gal) for 14 h. Cells from 5-7 random microscope fields were counted and (%) senescence was calculated as the ratio of β-gal positive cells to total cells. To determine miR expression, RNA was extracted from 1.0x10
5
cells and was quantified using RT-PCR. Cellular expression was normalized to RNU6 and calculated as fold change in ΔΔCt from control (N=4, experimental units). Both X4 (32.0±0.7% vs 18.3±1.7%) and R5 (30.2±3.8% vs 18.3±1.7%) significantly increased cellular senescence vs control. Moreover, the magnitude of increase (~65%) in senescent cells was similar between the glycoproteins. Cellular expression of pro-senescence miR-34a (1.60±0.04 fold) was increased (~60%; P<0.05) in response to X4 treatment compared with control. However, expression of miR-146a (1.34±0.36 fold) and miR-217 (1.38±0.36 fold) was not significantly affected by X4. In response to R5, cellular expression of miR-34a (1.23±0.07 fold) was significantly increased (~23%) and miR-146a (1.23±0.07 fold) was significantly decreased (~80%); miR-217 was not influenced by R5 (1.05±0.13 fold). These data indicate that HIV-1 viral protein gp120 induces endothelial cell senescence and adversely affects cellular expression of senescence-associated miRs. miR dysregulation may underlie the pro-senescent effects of gp120.
Abstract 58: Extracellular RNA Response to Acute Exercise
Authors: Shah Ravi V , Das Avash , Ziegler Olivia , Yeri Ashish , Courtright-Lim Amanda , Gervino Ernest , Ocel Jeffrey , Pinzon-Quintero Pablo , Pico Alexander , Chan Mun Chun , Lewis Gregory , Ghiran Ionita , Jenson Kendall , Das Saumya
Published: July 2021

The benefits of acute exercise on distant organs (including the neurocognitive system) have been recognized, suggesting existence of biomarkers that mediate exercise benefits in target organs. Extracellular RNAs (ex-RNAs) are RNA molecules stable in circulation, capable of regulating gene expression across multiple target organs at a distance. In 26 individuals without clinical cardiovascular disease (myocardial infarction or heart failure), we performed small non-coding RNA sequencing (RNA-seq) from plasma before and after symptom-limited treadmill exercise, with validation of selected microRNAs (miRNAs) in pulmonary arterial blood from 59 individuals referred for cardiopulmonary exercise testing. Acute exercise produced widespread shifts in the plasma ex-RNA transcriptome, with a host of novel ex-RNA subtypes with unknown function (e.g., yRNAs). miR-181b (involved in silencing of NFkB-mediated inflammation in obesity and vascular disease) was significantly increased at peak exercise (relative to rest) in both our discovery (2.3-fold increase after exercise, P=8.46x10
-11
) and validation cohort (P=0.02). In a mouse model of acute exercise, we found that skeletal muscle miR-181b expression increased in young but not old mice after exercise, with a corresponding reduction in miR-181b mRNA targets. These results provide the first unbiased demonstration of diversity in ex-RNA release after acute exercise in humans, and suggest anti-inflammatory benefits of acute exercise may be mediated in part by circulating non-coding RNAs.
Abstract 6: Restoration of Impaired Diastolic Function in Hypertrophic Cardiomyopathy Induced Pluripotent Stem Cell-derived Cardiomyocytes by Re-balancing the Calcium Homeostasis
Authors: Wu Haodi , Yang Huaxiao , Zhang Joe , Lam Chi Keung , Rhee June-Wha , Seeger Timon , Sallam Karim , Ma Ning , Wu Joseph
Published: July 2021

Background:
Diastolic dysfunction is commonly seen in hypertrophic cardiomyopathy (HCM). However, the cellular mechanism is not fully understood, and no effective treatment so far has been developed. We hypothesize here that HCM patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) can recapitulate the cellular mechanism, and provide us a platform for mechanistic study and for drug screening of diastolic dysfunctions in HCM.

Methods and Results:
We generated beating iPSC-CMs from healthy individuals and HCM patients carrying familial mutations (MYH7 R663H (n=2 lines) and MYBPC3 R943ter (n=2 lines)). Sarcomere shortening measurement in patterned iPSC-CMs with live cell confocal imaging showed significantly prolonged diastolic phase and slower relaxation velocity in HCM iPSC-CMs compared to WT cells. To elucidate the cellular mechanism, Fura-2 AM ratiometric calcium imaging showed marked elevation of resting calcium level and increased abnormal calcium handlings in HCM iPSC-CMs, which were exaggerated by β-adrenergic activation with isoproterenol. By applying calcium transient and contractile force simultaneous recording, we defined a “risk index of diastolic dysfunction” (measured as transient-contraction gain factor), which was significantly increased in HCM iPSC-CMs. Thus, both elevated basal calcium level and increased calcium sensitivity of myofilament contribute to the abnormal diastolic function in HCM iPSC-CMs. Gene expression profiling of HCM and WT iPSC-CMs indicated that increased calcium channels may underlie the increased basal calcium concentration in HCM cells. Indeed, partially blocking the calcium influx by calcium blockers reset the basal calcium level, attenuated calcium mishandling, and restored the diastolic function in HCM iPSC-CMs. Moreover, re-balancing calcium homeostasis significantly improved long-term survival rate of HCM iPSC-CMs at both basal level and under β-adrenergic stress.

Conclusion:
The iPSC-CM models carrying patient-specific HCM mutations recapitulated diastolic dysfunction on single cell level. Future studies using these platform may reveal additional novel cellular mechanisms and therapeutic targets of diastolic dysfunction in HCM disease.
Abstract 67: Polycystin-1 is Required for Normal Cardiomyocyte Excitability and Heart Function
Authors: Altamirano Francisco J , Schiattarella Gabriele G , Kyrychenko Sergiy , Schneider Jay W , Lavandero Sergio , Gillette Thomas G , Hill Joseph A
Published: July 2021

Mutations in the gene (
Pkd1
) encoding Polycystin-1 (PC-1) leads to autosomal dominant polycystic kidney disease (ADPKD). Although renal failure is the leading cause of death, cardiovascular alterations are described in ADPKD patients. Our lab has previously demonstrated that PC-1 is involved in cardiac L-type Ca
2+
channel (LTCC) protein stability, which is required for hypertrophic growth during mechanical stretch. PC-1 is expressed in cardiomyocytes and its gene ablation in mice decreases basal cardiac function. Here, we hypothesized that PC-1 regulates excitation-contraction coupling in cardiomyocytes. To test this hypothesis, we studied mice harboring floxed
Pkd1
alleles and a Cre transgene (α-MHC promoter) to engineer cardiomyocyte-specific PC-1 KO (F/F αMHC Cre, PC-1 cKO) mice. Human-derived cardiomyocytes were differentiated from embryonic stem cells (H9), and PC-1 was depleted using specific siRNA constructs. Fractional shortening measured by echocardiography was significantly reduced under basal conditions in PC-1 cKO mice compared with controls. Likewise, adult ventricular cardiomyocytes isolated from PC-1 cKO mice manifested decreased contractility (measured by Ionoptix) and a reduced Ca
2+
transients (measured using Fluo-8AM and line scan) during pacing (0.5 Hz). Unexpectedly, assessment of both Ca
2+
stores (caffeine-evoked Ca
2+
transients) and Ca
2+
entry (LTCC currents, whole-cell voltage clamp) showed no differences between PC-1 cKO and control cardiomyocytes. Remarkably, Ca
2+
transients evoked by high K
+
depolarization were similar across genotypes, suggesting an alteration in excitability. Indeed, action potential duration (measured by current clamp or FluoVolt) was shorter in cardiomyocytes lacking PC-1 (mouse adult cardiomyocytes and hESC-derived cardiomyocytes). Moreover, PC-1 cKO mice manifested shorter QT intervals on ECG, and a pharmacological intervention with quinidine improved cardiac function and cardiomyocyte contractility to near-normal levels. Our findings uncover a novel role for PC-1 as an important regulator of cardiac function, required to fine-tune both excitability and contraction in ventricular myocytes.
Abstract 69: Cardiac Fibrosis Induced by Mkk6-p38 Activation Alters Myocardial Stiffness and Myofilament Function
Authors: Moussavi-Harami Farid , Razumova Maria V , Klaiman Jordan M , Bugg Darrian , Regnier Michael , Davis Jennifer
Published: July 2021

Heart failure with preserved ejection fraction (HFpEF) accounts for at least half of the patients with heart failure, but to date there are no proven therapies for these patients. Cardiac fibrosis and increased collagen content plays an important role in the pathophysiology of HFpEF. Studies in human HFpEF patients have indicated increased cardiac fibrosis, myocardial stiffness and myofilament calcium sensitivity. However, it is unclear how and if cardiac fibrosis directly alters myofilament function. In this study we used a new model of cardiac fibrosis genetically induced by the constitutive activation of MKK6-p38 (MKK6-Tg) signaling specifically in resident cardiac fibroblasts to determine the effect of fibrosis on myofilament stiffness and function. The MKK6-Tg mice develop interstitial and perivascular fibrosis in the heart accompanied with severe diastolic dysfunction, although systolic function remains normal. We measured the passive stiffness and isometric contractile properties of demembranated papillary muscle preparations. Our results show an increase in passive stiffness in demembranated papillary muscles from MKK6-Tg mice compared to NTG littermates when stretched to 24% from sarcomere length of 2.0 μM. Passive tension at SL=2.3 was significantly increased in MKK6-Tg mice (28±4 vs. 13±3 mN/mm
2
, P<0.05) compared to NTG mice, which was ascribed to changes in Titin isoform as well as extracellular matrix composition. The MKK6-Tg mice also show an increase in Ca
2+
sensitivity (pCa
50
=5.72±0.05 vs. 5.56±0.02, P<0.05). This was associated with an increased rate of force redevelopment in MKK6-Tg mice compared to NTG littermates (k
TR
=35±8 vs. 22±3 s
-1
). Towards understanding the mechanism of these myofilament changes we performed phosphate affinity electrophoresis and saw decreased phosphorylation of both Troponin I and Troponin T in MKK6-Tg hearts. There was no change in troponin I phosphorylation level at Ser23/24, indicating role of none-PKA mediated phosphorylation in mechanical changes seen in this model.
Abstract 80: Interplay Between Cell-cell and Cell-extracellular Matrix Forces Regulate Myocardial Proliferation
Authors: Zhang Caimei , Radice Glenn
Published: July 2021

Changes in expression and distribution of integrin, fibronectin (FN), and N-cadherin in the postnatal heart accompany the switch from hyperplastic to hypertrophic growth. As FN decreases after birth, N-cadherin/catenin complex accumulates at the cell termini creating a specialized type of cell-cell contact called the intercalated disc (ID). Integrin-FN interactions promote cardiomyocyte and cardiac progenitor cell proliferation. However, little is known regarding the reciprocity between integrin and N-cadherin adhesions in the regulation of myocardial proliferation. Alpha-catenins function as mechanosensors and transduce the intercellular force from N-cadherin to the actin cytoskeleton. To investigate mechanotransduction in the heart, we generated cardiac-specific αE- and αT-catenins double knockout (DKO) mice. The relationship between N-cadherin, integrin, and FN was examined at postnatal day (P) 4, P7, P14, and P60. DKO hearts exhibited aberrant N-cadherin expression accompanied by increased expression of α5/β1 integrin, the primary receptor for FN. Normally found at the lateral membrane, α5 and FN accumulated at the ID along with N-cadherin in DKO hearts. FN-integrin binding leads to the formation of FN fibrils that are initially soluble in the detergent deoxycholate (DOC) but are gradually converted into a stable, DOC-insoluble form that comprises the mature matrix. Both α5 and FN were increased in the DOC-insoluble fraction consistent with enhanced matrix assembly in DKO hearts. Activation of focal adhesion kinase (FAK) and p130CAS were observed in the DKO hearts consistent with increased cell-extracellular matrix interactions. Complementary experiments performed with deformable substrata demonstrated that stiffness-mediated Yap nuclear accumulation was dependent on FAK activity. These data demonstrate that α-catenins regulate the balance between cell-cell and cell-matrix adhesions, which, in turn, controls Yap subcellular localization, thus providing a molecular explanation for loss of regenerative potential in the adult heart.
Abstract 82: Wnt11 Regulates Chamber Specific Neonatal Cardiomyocyte Proliferation During Perinatal Circulatory Transition
Authors: Touma Marlin , Kang Xuedong , Gao Fuying , Zhao Yan , Biniwale Reshma , Chen Jau-Nian , Coppola Giovanni , Reemtsen Brian , Wang Yibin
Published: July 2021

Background:
Fetal to neonatal transition of heart involves major changes in cardiomyocytes (CMC) including proliferative capacity. However, the chamber specific CMC proliferation programs of remain poorly understood. Elucidating the mechanisms involved is critical to develop chamber specific therapies for newborn infants with single ventricle physiology and other congenital heart defects (CHDs).

Methods:
Transcriptomes of mouse left ventricle (LV) and right ventricle (RV) were analyzed by RNA-seq at postnatal days 0 (P0), P3 and P7. R package and Ingenuity suite were used for weighted gene co-expression network analysis (WGCNA) and gene ontology studies. Mechanistic analysis was conducted using gain and loss of function approaches.

Results:
Mouse neonatal cardiac transcriptome was mostly affected by developmental stage. WGCNA revealed 5 LV and 8 RV modules that were significantly correlated with maturation stage and highly preserved between both ventricles at P0 and P7. In contrast, P3 specific gene modules exhibited the largest chamber specific variations in cell signaling, involving proliferation in LV and Wnt signaling molecules, including Wnt11, in RV. Importantly, Wnt11 expression significantly decreased in cyanotic CHDs phenotypes and correlated with O2 saturation levels in hypoxemic infants with Tetralogy of Fallot (TOF). Notably, Perinatal hypoxia treatment in mice suppressed Wnt11 expression, induced CMC proliferation, downregulated Rb1 expression and enhanced Rb1 phosphorylation more robustly in RV vs. LV. Remarkably, Wnt11 inactivation was sufficient to induce myocyte proliferation in perinatal mouse heart and reduced Rb1 expression and phosphorylation in primary neonatal CMC. Importantly, downregulated Wnt11 in hypoxemic TOF infantile heart was also associated with Rb1 suppression and inversely correlated with proliferation marker Plk1 in human.

Conclusion:
Using integrated systems genomic and functional biology analyses of perinatal cardiac transcriptome, we revealed a previously uncharacterized function for Wnt11 in chamber specific growth and cyanotic CHD. Reduction of Wnt11 expression by hypoxia plays a critical role in neonatal CMC proliferation via modulating Rb1 expression and activity.
Abstract 97: Induction of Hexosamine Biosynthetic Pathway Promotes Cardiac Hypertrophy through Activation of O-GlcNAcylation
Authors: Tran Diem H , Li Jianping , Wang Xiaoding , May Herman I , Schiattarella Gabriele G , Gillette Thomas G , Wang Zhao V
Published: July 2021

Background & significance:
Heart failure affects approximately 6 million Americans, with 5-year survival of 50%, which is responsible for a huge burden on the US economy and healthcare system. The relevance and significance of the metabolic alteration to the pathogenesis of pressure overload-induced cardiac hypertrophy and heart failure are largely unknown. The hexosamine biosynthetic pathway (HBP) that is linked to metabolism of glucose, fatty acids and amino acids, has been implicated in the pathophysiology of heart diseases.

Methods & results:
Thoracic aortic constriction (TAC) was performed to induce heart failure by pressure overload in mice. At the in vitro levels, treatment of phenylephrine (PE, 50 μM) was used to induce cellular hypertrophy in neonatal rat ventricular myocytes (NRVM). Our data revealed that all the enzymes of the HBP were upregulated while induction of hypertrophy at both in vivo and in vitro levels. Consistently, the intermediate product of the HBP was elevated in heart by afterload stress, as measured by metabolomics analyses. In the transgenic mice model for Gfat1, the rate-limiting enzyme of the HBP, we found more profound cardiac hypertrophy and cardiac remodeling in response to pressure overload. The increase of O-GlcNAc was also observed. In addition, the regulation of O-GlcNAcylation by specific targeting of two enzymes of the HBP (1 mM Alloxan, an inhibitor of OGT and 10 μM PUGNAc, an inhibitor of OGA) in NRVM suggested an involvement of the mTOR signaling in the activation of O-GlcNAc levels and the hypertrophy response. Targeting of the HBP by either specific siRNA or Gfat1 inhibitor (Azaserine, 5 μM) led to decrease in cellular hypertrophic response.

Conclusions:
Together, our data strongly suggest that the HBP participates in cardiac hypertrophic growth and pharmacologic targeting of the HBP may represent a novel approach to ameliorate pathological remodeling.
Antihypertensive Effect of Clonidine
Authors: ONESTI GADDO , SCHWARTZ ALLAN B. , KIM KWAN E. , PAZ-MARTINEZ VIRGILIO , SWARTZ CHARLES
Published: July 2021

Clonidine hydrochloride is a sympathetic inhibitor with central site of action. The antihypertensive effect in man in the supine position is associated with a decrease in cardiac output and no consistent changes in total peripheral resistance. In the standing position, however, in addition to the decrease in cardiac output, a fall in total peripheral resistance becomes evident. The fall in blood pressure results in no significant alteration in renal blood flow or glomerular filtration rate in the supine position. In the standing position a consistent decrease in renal vascular resistance is seen.

In the anesthetized dog the intravenous administration of clonidine produces a significant reduction of renal vein plasma renin activity. Similarly, in patients with essential hypertension oral administration of the drug results in a decrease in peripheral plasma renin activity.

In ambulatory essential hypertensive patients treated with clonidine alone in doses of 400 to 900 µg per day, a modest antihypertensive effect is achieved. When clonidine is used with a diuretic, antihypertensive efficacy is achieved in 80% of the patients treated. In higher doses (up to 3,600 µg per day) and in combination with a diuretic, the antihypertensive effect appears to be superior to that of many of the standard agents. Drowsiness and dryness of the mouth are the most frequent and serious side effects with the higher doses.
Crossed Nonaphasia in a Dextral With Left Hemispheric Lesions
Authors: Hund-Georgiadis Margret , Zysset Stefan , Weih Kathrin , Guthke Thomas , von Cramon D. Yves
Published: July 2021

Background
—

General conclusions concerning mechanisms of cerebral lateralization may be learned from the investigation of functional brain organization in patients with anomalous lateralization.

Case Description
—

The functional organization of language, attention, and motor performance was investigated in a 42-year-old patient with crossed nonaphasia by means of functional MRI. The strongly right-handed man experienced a left middle cerebral artery infarction documented by MRI without exhibition of aphasia. However, the left hemispheric stroke was accompanied by visuospatial impairment, right-sided slight sensory and motor paresis, and right homonymous hemianopia. No history of familial sinistrality or prior neurological illness was present. Functional MR language mapping revealed strong right hemispheric activation in inferior frontal and superior temporal cortices. Finger tapping with the right hand recruited ipsilateral premotor and motor areas as well as supplementary motor cortex. A Stroop task, usually strongly associated with left-sided inferior frontal activation in dextrals, resulted in strong right hemispheric frontal activation.

Conclusions
—

From our data there is clear evidence that different modalities, such as language perception and production, attention, and motor performance, are processed exclusively by 1 hemisphere when atypical cerebral dominance is present.
Transcriptional Responses in Recovery from Stroke
Authors: Bolanos Sandra , Saito Hiroshi , Papaconstantinou John , Kent Thomas A
Published: July 2021

1

Multiple lines of evidence support synaptic reorganization of the brain after stroke and a role in functional recovery. Molecular, pharmacological, especially norardrenergic, and behavioral methods have shown promise in enhancing recovery in animal or clinical studies. However, the mechanisms underlying stimulation of new synapses remain largely unknown, information that is critical to optimize interventions, including stem cell transplant, drug therapy or other approaches. We investigated two potential such mechanisms in a rat model of middle cerebral artery occlusion (MCAO) in which we have previously shown robust new expression of the pre-synaptic vesicle protein synaptophysin in the peri-infarct and contralateral homotopic regions. One candidate signal for stimulation of new synaptic formation is the polysialated form of neuronal cell adhesion molecules (PSCAM) that is expressed during synaptic development. Immunostaining for PSCAM after MCAO and recovery failed to demonstrate expression. The possibility that signal molecules potentially released following ischemia, may be involved in synaptic generation analogous to long term potentiation (LTP), was next investigated. The C/EBP (CCAAT enhancer binding protein) family of transcription factors is an important intermediary for glutamate stimulation of synapses in LTP. After distal MCAO in rats, we found dramatic expression of the C/EBP α subtype in the peri-infarct region at 3 days, and expression by Western blot of a 30 kD C/EBP α isoform in cultured PC12 cells induced to differentiate into neurite and synapses. We suggest the possibility that C/EBP, stimulated by biochemical events in the peri-infarct region, is a potential signal for new synapses following stroke. We are in the process of assessing the effect of overexpression of this isoform on synapse formation in cultured PC12 cells. C/EBP α and other signals may provide targets for intervention to enhance expression. The importance of these results as related to the effects of glutamate also support our previous finding that glutamate-blockade, although limiting infarct size, may also interfere with synapse formation in the long term (Bolanos & Kent, JCBF & Met Suppl, 1999).
Changes in Diffusion-Weighted Images During Transient Cerebral Hypoxia-Ischemia Correlate with Reductions in Extracellular Space using Electron microscopic and Impedance Techniques.
Authors: Qiao Min , Ringland Kathy , Foniok Tadeusz , Bascaramurty Saro , Malisza Kris L , R Del Bigio Marc
Published: July 2021

2

Background:
Experimental animal and clinical studies indicate that diffusion-weighted imaging detects early ischemic changes which are assumed to reflect reductions in extracellular space and cellular edema. In the present study, we investigate this directly by measuring intensity changes in diffusion-weighted images and alterations in extracellular space using electron microscopic and impedance techniques during and after transient cerebral hypoxia/ischemia in rats.
Methods:
The right carotid artery was isolated surgically (sham control) or occluded with subsequent exposure to 8% oxygen for 2 hours in 31 one-week old Wistar rats. Diffusion-weighted images were obtained prior to, during, at 1 or 24 hours post hypoxia/ischemia. Animals were decapitated after either the sham procedure, during hypoxia/ischemia or at 1 or 24 hours post hypoxia/ischemia. The rat brain was flash frozen and processed for electron microscopic quantitation of extracellular space immediately after imaging. Extracellular space was also assessed by recording impedance changes prior to, during and for 1 hour post hypoxia/ischemia.
Results:
Intensity on diffusion-weighted images increased 78% ipsilaterally during hypoxia/ischemia, substantially recovered at 1 hour post hypoxia/ischemia, and increased 49% again at 24 hours post hypoxia/ischemia. Stereologic analysis of extracellular space from electron micrographs of the cortex in controls was 51 ± 6% of total space. This decreased to 3 ± 1% during hypoxia/ischemia, returned to 30 ± 21% at 1 hour post hypoxia/ischemia and was 43 ± 7% at 24 hours post hypoxia/ischemia. Impedance measurements within the ischemic cortex demonstrated that extracellular space decreased 40% during hypoxia/ischemia and recovered to control levels at 1 hour post hypoxia/ischemia.
Conclusions:
Increased intensity on diffusion-weighted images corresponds well to a reduction in extracellular space.
Viral vector mediated Hsp72 overexpression protects against global cerebral ischemia and when given after experimental stroke
Authors: Yenari Midori A , Ringer Thomas M , Zhang Zhijian , Fink Sheri L , Ho Dora Y , Sapolsky Robert M , Steinberg Gary K
Published: July 2021

5

INTRODUCTION:
We and others have previously shown that the stress protein HSP72 protected against focal cerebral ischemia and excitotoxin exposure when overexpression occurred prior to the insult, provided the extent of transgene expression was sufficiently high, and the insult not too severe. Whether HSP72 overexpression is protective after focal ischemia or in other brain ischemia models is unknown. We studied whether HSP72 protected when delivered after a stroke, and also if it protected CA1 cells against global cerebral ischemia by using amplicon based viral vectors that permit high levels of transgene expression.
METHODS:
Bipromoter, defective herpes simplex vectors expressing HSP72 and β-galactosidase as a reporter (or β-galactosidase only as a control) were delivered to the striata of 21 rats 20min after 1h MCA occlusion. 48h after reperfusion, the number of remaining reporter gene positive neurons were counted and expressed as ratio of the number of surviving cells between ischemic to nonischemic hemispheres. 15 h prior to the onset of global cerebral ischemia (bilateral common carotid artery occlusion plus hypotension; n=9), similar vectors were injected into each CA1 hippocampal subsector. Reporter gene positive cells in CA1 were counted and compared to counts in sham operated rats injected with vector (n=4).
RESULTS:
Survival among HSP72 treated groups was significantly higher for both experiments. After post insult delivery in the MCA occlusion model, 54.7±8.6% of HSP72 treated cells remained versus 31.2±5.1% of control vector treated (P<0.03). Following global cerebral ischemia, 31±8% of HSP72 treated CA1 neurons remained compared to 10±4% among controls (P<0.05).
CONCLUSIONS:
To our knowledge, this is the first study to show that postischemic HSP72 overexpression is protective, and that HSP72 protects CA1 neurons from global cerebral ischemia. This suggests that this stress protein may be a useful therapeutic target because it protects against a variety of insults and is also effective when treatment is delayed.
Clinical and Radiological Correlates of Reduced CBF Measured Using MRI
Authors: Thijs Vincent N , Neumann-Haefelin Tobias , Moseley Michael E , Marks Michael P , Albers Gregory W
Published: July 2021

11

Background and purpose Methods for determining CBF using IV bolus tracking MRI have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional cerebral blood flow (rCBF). We studied the clinical and radiological features of patients with severe reductions of rCBF on MRI and analysed the relationship between reduced rCBF and ADC. Methods We studied patients with non-lacunar acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset. A PWI>DWI mismatch of >20% was required. Maps of rCBF, cerebral blood volume (rCBV) and mean transit time (rMTT) were generated after deconvoluting the measured concentration-time curve with the arterial input function using singular value decomposition. The ischemic lesion was outlined on the MTT map and the region of interest (ROI) transferred to the rCBF and rCBV map. ADC-maps were calculated. ADC lesions were defined as regions with ADC values ≤ 550
μm
m2/sec. We compared the characteristics of patients with ischemic lesions that had a relative CBF of <50% to the contralateral hemisphere to patients with lesions that had relative CBF of >50%. Characteristics analysed included age, time to MRI, baseline NIHSS, mean ADC, DWI lesion volume, PWI lesion volume and absolute mismatch volume. Results Fifteen patients with an initial PWI>DWI mismatch of >20% were included. Ten had lesions with rCBF of >50% (median 60%) and five patients had rCBF of <50% (median 27.7%). Patients with rCBF <50% had lower ADC values (median 431 μmm2/sec versus 506
μ
mm2/sec, p=0.028), larger DWI volumes (median 75.6 cm
3
versus 8.6 cm
3
, p=0.001) and larger PWI lesions as defined by the MTT volume (median 193 cm
3
versus 69 cm
3
, p=0.028) and more severe baseline NIHSS scores (median 18 versus 9, p=0.019). The rMTT and rCBV of the lesions were similar in both groups, as were the age, the absolute mismatch volume and the time from symptom onset to MRI. Conclusion These data indicate that ischemic lesions with severe CBF reductions, measured with new MRI techniques, are associated with a lower mean ADC, larger DWI and PWI lesion volumes and a higher NIHSS score.
Conventional Diffusion Weighted Imaging In Acute Stroke Overestimates Apparent Diffusion Coefficient (ADC): Improved Accuracy of ADC Measurements of Brain Using Fluid-Inversion Prepared Diffusion (FLIPD) Imaging
Authors: Latour Lawrence L , Warach Steven
Published: July 2021

13

Background:
The measurement of ADC of water in brains of stroke patients is used in developing tissue models of reversible from irreversible injury. Cerebrospinal fluid (CSF) has a higher ADC and T2 value than parenchyma and measurement of lesion ADC by conventional EPI methods may be overestimated by the presence of CSF in sulci and perivascular spaces. We investigated whether the suppression of signal from CSF using an inversion recovery MRI method would give different ADC values than with the conventional DWI technique.
Methods:
Thirteen consecutive patients with stroke onset of less than 6 hours and an acute lesion on conventional DWI were studied. Conventional isotropic DWI was a T2-weighted single shot EPI technique with a b value of 1000 s/mm2. CSF suppression was achieved by the addition of an inversion pulse (TI = 2200 ms) at the beginning of the DWI sequence. The method is termed Fluid-Inversion Prepared Diffusion (FLIPD), and it is a combination of FLAIR and DWI in a single sequence. The region of the acute lesion was identified on the conventional DWI and the ADC of that region was measured in both the conventional and FLIPD ADC images.
Results:
In all 13 patients, FLIPD ADC was lower than conventional ADC. The mean (SD) of the 13 patients’ lesion ADC was 0.587 (0.075) x 10
-3
mm/s with FLIPD and 0.696 (0.078) x 10
-3
mm/s with conventional DWI (p < 0.0001). The distribution of ADC values in all voxels pooled across all subjects indicated a narrower distribution of for FLIPD ADC (SD = 0.128 vs. 0.220 x 10
-3
mm/s for lesions and (SD = 0.151 vs. 0.514 x 10
-3
mm/s for normal brain). The reduced variance in FLIPD ADC improved the diagnostic conspicuity of FLIPD ADC lesions.
Conclusions:
Suppression of CSF leads to lesion ADC values more homogeneous and greater than 15% lower than with conventional EPI DWI techniques. We suggest that FLIPD ADC measurements are more accurate and give more diagnostically useful images than conventional ADC maps. Because FLIPD measures water diffusion within parenchyma only, it should be more sensitive to ischemic changes.
Predictors of Hemorrhagic Transformation Following Intra-Arterial Thrombolysis
Authors: Kidwell Chelsea S , Saver Jeffrey L , Duckwiler Gary , Starkman Sidney , Saver Jeffrey L , Gobin Pierre , Jahan Reza , Carneado Joaquin , Liebeskind David S , Vespa Paul M , Villablanca J. Pablo , Vinuela Fernando
Published: July 2021

18

Background:
Hemorrhagic transformation is a major complication of intra-arterial (IA) thrombolytic therapy. Delineation of significant predictors of intracerebral hemorrhage (ICH) following thrombolysis would be useful to guide patient selection for IA treatment.
Methods:
Data were collected on consecutive patients with acute cerebral ischemia treated with IA thrombolysis over an 8 year period at UCLA Medical Center. Patients received either pure IA thrombolytics (tPA or urokinase) or combined intravenous/intra-arterial (IV/IA) tPA. Using univariate and multivariate analyses, 58 variables were examined as potential predictors of ICH.
Results:
A total of 89 patients were treated, 77 anterior circulation, 12 posterior circulation. Median baseline NIHSS score was 16. 26 patients received IA tPA only, 22 IV/IA tPA, and 41 IA urokinase only. Asymptomatic ICH occurred in 29 patients (33%), minor symptomatic ICH in 10 (11%), and major symptomatic ICH in 6 (7%). Of the 45 patients with M1 or M2 MCA occlusions treated with pure IA thrombolysis, 4 (9%) had major symptomatic ICH. There was no difference in the rate of any ICH with pure IA thrombolysis (39%) vs. combined IV/IA thrombolysis (41%). In pure IA cases, there was no difference in ICH rate between tPA and urokinase. 86% of patients with any ICH were dead or disabled (MRS > 2) at day 7 vs. 39% without ICH (p<0.0001). On univariate analysis, significant predictors of ICH were NIHSS score, time to recanalization, serum glucose level, platelet count, hematocrit, active treatment with warfarin, and degree of recanalization. In both multivariate stepwise linear discriminant and CART analyses, independent predictors of ICH were NIHSS score, time to recanalization, and platelet count. A model using these variables correctly predicted hemorrhagic transformation with PPV 80% and overall accuracy 75%.
Conclusions:
In this large series of patients treated with intra-arterial thrombolysis, higher NIHSS score, longer time to recanalization, and lower platelet count were independent predictors of hemorrhagic transformation. A model incorporating these variables identified patients who would develop ICH with 75% accuracy.
The decline in stroke mortality: an analysis of temporal patterns by sex, race and geographic region
Authors: Howard George , Howard Virginia J , Katholi Charles R , OIi Madan K
Published: July 2021

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Introduction:
While stroke mortality rates have declined rapidly over the past 30 years, the decline has slowed to a plateau. Herein, we: (1) assess if the race-sex-regional groups have participated equally in this decline, (2) assess if there are race-sex-regional groups where stroke mortality rates continue to decline (i.e., regions or groups not at plateau), and (3) predict how stroke mortality rates will differ by race, sex, or region in the future.
Methods:
Data on stroke mortality between 1968 and 1996 from the Compressed Mortality File were analyzed in a three-step procedure: (1) “crude” age-adjusted stroke mortality rates were calculated by race and sex at the county level, (2) these rates were “smoothed” across the counties and years, and (3) a model was fit to describe the temporal pattern of mortality rates by county. The following parameters were then calculated: (1) the percent decline in stroke mortality between 1968 and 1996, (2) the anticipated percent decline to the “floor” for stroke mortality rates, and (3) the anticipated floor of the stroke mortality rates.
Results:
Race/sex specific maps show the geographic variations in the above parameters, and indicate substantial differences in the decline in stroke mortality in the past, and in the predicted decline in the future. White males have had the largest decline of stroke mortality and black males the smallest. Generally, stroke mortality appears to still be declining (slowly) for African Americans, but not for whites. Racial and gender differences in stroke mortality are predicted to persist when stroke mortality rates plateau.
Discussion:
The analysis suggests that the deep south (AL and MS) will fall from the highest stroke mortality rates in the nation and be replaced by other regions (notably OR, WA and AR). New York City and Southern FL had very low stroke mortality rates in 1968, have experienced large declines and also appear to be experiencing continued substantial declines — resulting in even greater geographic heterogeneity of stroke mortality rates. The reasons for these differences between race, sex and region in the pattern of the decline in stroke mortality are not understood.
Lack of an Increased Expression of the CD11b/CD18 Antigen on the Surface of Peripheral Blood Circulating Pool of Leukocytes in Patients with an Acute Neurological Ischemic Event
Authors: Zeltser David , Karepov Vadim G , Bornstein Natan M
Published: July 2021

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OBJECTIVE:
To reveal the intensity of the surface expression of the adhesion molecules (CD11b/CD18) on monocytes and neutrophils in the peripheral blood of patients with an acute brain ischemia compared to healthy individuals who served as controls.
BACKGROUND:
The Leukocyte Integrin CD11b/CD18 is an important receptor that is involved in the modulation of leukocyte to endothelial interactions and is expressed in increased amounts during cell activation. It has been previously suggested that activated white blood cells, mainly polymorphonuclear leukocytes and monocytes, participate in the development of ischemic vascular disorders by virtue of their capability to obstruct the microvasculature and enhance tissue damage.
DESIGN/METHODS:
Cellular surface expression of the adhesion molecules CD11b/CD18 on the neutrophils and monocytes in the peripheral blood was measured by a direct immunotechnique of flow cytometry in two groups: patients who had transient ischemic attacks (TIA) or ischemic stroke (confirmed by CT scans, within 24 hours from onset of symptoms), and healthy individuals who served as controls. Analysis was done by ANOVA test.
RESULT:
Seventy-one patients and 150 controls were included in the study. The respective mean fluorescence intensity for CD11b/CD18 being 161±76, 155±87 for polymorphonuclear leukocytes and 231±99, 203±79 for monocytes. No statistically significant difference was noted between the groups.
CONCLUSIONS:
The results of the present study show that patients with acute cerebral ischemic event do not present increased amount of the CD11b/CD18 antigen on the surface of the peripheral blood polymorphonuclear or monocytes compared to control. Our data do not support the hypothesis that the white blood cells participate in the development of acute cerebral ischemia by the mechanism of activation of the adhesion molecule CD11b/CD18.
Stroke After Bone Marrow Transplantation: Frequency, Etiology, and Outcome
Authors: Coplin William M , Cochran Mary S , Levine Steven R , Crawford Steven L
Published: July 2021

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Background and Purpose
–Little data exist on the frequency, etiology, and outcome of cerebrovascular complications of bone marrow transplantation (BMT).
Methods
–We reviewed all patients undergoing BMT at the Fred Hutchinson Cancer Research Center, Seattle, WA (a large referral institution) over three years. We reviewed ICD-9 codes for ischemic stroke, seizure, intracranial hemorrhage, and brain infection. Using standardized forms, we paid detailed attention to: clinical features and demographics, oncological diagnosis, conditioning regimens, neurological history, comorbidities, time from BMT to ictus, cerebrovascular subtype, radiological and pathological features, and outcomes.
Results
–We identified 36 patients with stroke from 1,245 patients who had BMT (2.9%) over three years. These patients’ median age was 35 (range 5–60, interquartile 25–45) years. The most common causes of stroke were intracranial hemorrhage related to thrombocytopenia (38.9%) and infarction or hemorrhage secondary to fungal infection (30.6%). Twenty-five patients (69.4%) died from their stroke; none survived without disability. Using a logistic regression model, neither demographic (e.g., age, gender) nor clinical (e.g., oncological diagnosis, type of BMT, time of stroke after BMT) factors predicted outcome.
Conclusions
–Stroke occurs relatively frequently after BMT (almost 3% incidence), has a relatively high frequency of infection-triggered events, has a neurological outcome not easily predicted from available data, and is often fatal.
CT Perfusion Imaging Improves Infarct Conspicuity in Hyperacute Stroke
Authors: Bove Peter , Lev Michael H , Berdichevsky Dmetri , Harris Gordon J , Alpert Nathaniel M , Thangaraj Venkatesan , Koroshetz Walter J , Putman Christopher , Gonzalez Ramon G
Published: July 2021

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Purpose:
To compare infarct conspicuity and image quality of noncontrast CT (NCCT), CT perfusion (CTP), and CT subtraction cerebral blood volume (CT-CBV) images of patients with hyperacute stroke.
Background:
NCCT is typically the first imaging test obtained in the evaluation of acute stroke. Whole brain CTP imaging is performed, simultaneously with CT angiography, during the steady state administration of IV contrast. Subtraction of coregistered NCCT images from the CTP images yields maps of perfused blood volume (CT-CBV). Ischemic areas on each of the NCCT, CTP, and CT-CBV images appear as hypodense, low attenuation regions. Materials and
Methods:
We reviewed the images of 20 consecutive patients with MCA stem occlusion who underwent intra-arterial thrombolysis within 6 hours of stroke onset. All had NCCT and CT angiography with CTP imaging prior to thrombolysis. Subtraction CT-CBV maps were created and analyzed using proprietary software (IMIPS, Inc). For each of the NCCT, CTP, and CT-CBV images, infarct conspicuity was defined by dividing the mean attenuation difference between normal and maximally hypodense gray matter by the mean normal gray matter attenuation. Contrast-to-noise ratio (CNR) was defined by dividing the same numerator by the standard deviation of the normal gray matter attenuation values. Statistical analysis was by ANOVA and students t-test.
Results:
Overall infarct conspicuity was 0.11 for the NCCT, 0.22 for the CTP, and 0.98 for the CT-CBV images (p<0.003 for all maps). Mean CNR was 0.95 for the NCCT, 1.94 for the CTP, and 1.12 for the CT-CBV images (p<0.01, for the CTP maps only).
Conclusions:
CT perfusion and CT-CBV subtraction imaging improve infarct conspicuity over that of NCCT in patients with hyperacute stroke. True reduction in blood pool (as reflected by CT-CBV), rather than increase in tissue edema (as reflected by NCCT), may explain much of the improved infarct delineation in CTP imaging. Because CNR is greater for CTP than for subtraction images, concurrent review of NCCT, CTP, and CT-CBV images may be indicated for optimal CT assessment of hyperacute MCA stroke.
Impact of contrast CT angiography and whole brain contrast CT perfusion study on the accuracy of cerebrovascular diagnosis in patients presenting with a major stroke-like syndrome
Authors: Ezzeddine Mustapha A , Lev Michael H , McDonald Colin T , Rordorf Guy A , Oliveira-Filho Jamary , Aksoy Fatma , Segal Alan Z , Gonzalez Gilberto , Koroshetz Walter J
Published: July 2021

52

Objective:
The diagnosis of ischemic stroke subtype is difficult in the emergency setting when based only upon a non-contrast CT scan and clinical findings. Accurate diagnosis may be important because prognosis depends upon the size and location of the infarct and emergency therapeutic decisions rest upon attempts to improve prognosis. Diffusion/perfusion weighted MR identifies acute ischemia and ischemic injury but is expensive, and not consistently accessible nationwide. We investigated the ability of a readily available CT contrast study (CT angiography, CTA; and whole brain CT perfusion, CTP) to enhance diagnostic accuracy of stroke subtype.
Methods:
All patients (1/97–12/98) who received a CTA within 24 hours of stroke onset (mean=4.6 hrs) and a follow-up CT or MRI within 2 weeks were analyzed (N=40). Stroke neurologists made stroke subtype diagnoses based upon: 1) non contrast CT and clinical vignette; 2) #1 and CTA; 2) #1, #2 and CTP. Diagnostic accuracy at each sequential step was measured against the gold standard based upon all available clinical, lab and follow-up imaging information.
Results:
The addition of the contrast CT study (CT+CTP)led to a statistically significant, relative improvement in accuracy of 1)infarct localization, 100%; 2) involved vascular territory, 69%; 3) occluded vessel, 94%; 4) TOAST stroke subtype, 44%; and 5) Oxfordshire stroke subtype, 81%. CTA led to significant improvement in diagnostic accuracy of vessel occlusion and TOAST subtype. CTP led to significant improvement in diagnostic accuracy of infarct localization, vascular territory and Oxfordshire classification.
Conclusion:
The addition of a contrast CT study to evaluate the intracranial vessels (CTA) and whole brain perfusion (CTP) enables highly accurate diagnosis of stroke subtype in the emergency setting. The ability of this widely accessible, emergency neuroimaging technique to predict functional outcome and guide therapeutic decisions can now be investigated.