The expression of ProBDNF and its high affinity receptor P75NTR in the neurons of emotion-related brain regions of post-stroke depression rats

OBJECTIVE

To investigate the expression of the precursor of brain-derived neurotrophic factor (proBDNF) and its high-affinity receptor p75NTR in neurons of emotion-related brain areas (prefrontal cortex, hippocampus, and amygdala) in rats with post-stroke depression (PSD), and to explore the expression levels of proBDNF and p75NTR in neurons of emotion-related brain areas by injecting tissue plasminogen activator (t-PA) into the lateral ventricle of PSD rats, this significantly improved the stress-induced depression-like behavior,thus further validating the above results.

METHODS

Rats were randomly divided into four groups: a normal control group (n = 8), a depression group (n = 8), a stroke group (n = 8), and a PSD group (n = 8). The rat model of stroke was established by thread embolism, and the PSD animal model was induced by chronic unpredictable mild stress (CUMS) and solitary feeding. Behavioral tests were conducted, including weight measurement, open field tests, and sucrose preference tests. Immunofluorescence double labeling was used to detect the expression of proBDNF and p75NTR in neurons of emotion-related brain regions in the PSD rat model. Four weeks after CUMS treatment, the PSD group was selected. Rats were infused with t-PA (3 μg dissolved in 6 μL saline, Boehringer Ingelheim), proBDNF (3 μg dissolved in 6 μL saline, Abcam), or equal-volume NS once per day for 7 consecutive days using the syringe pump connecting to injection needles. After 7 days of continuous administration, animal behavior was assessed through scoring, and the expression of proBDNF and p75NTR in the emotion-related brain regions of the PSD rat model was detected using immunofluorescence double labeling.

RESULTS

Compared with the normal control group and the stroke group, the body weight, sucrose water consumption, and vertical movement distance in the PSD group were significantly lower (P < 0.05). In contrast, when compared with the proBDNF injection group and saline injection group, the weight, sucrose water consumption, field horizontal movement, and vertical movement distance of the t-PA injection group significantly increased after PSD lateral ventricle intubation.Double immunofluorescence revealed a higher neuronal expression of proBDNF as well as p75NTR in the prefrontal cortex and hippocampus of PSD rats compared to control animals (P < 0.05). In the amygdala, the expression levels of proBDNF and P75NTR were significantly reduced in the PSD group compared to the control group (P < 0.05). The results of the expression levels of proBDNF and P75NTR in the emotion-related brain regions of PSD rats injected with t-PA showed that proBDNF and P75NTR was significantly reduced in the prefrontal cortex, hippocampus, and amygdala of PSD rats compared to those of the NS and proBDNF groups (P < 0.05).

CONCLUSIONS

The increased expression of the brain-derived neurotrophic factor precursor proBDNF and its receptor p75NTR in neurons of emotion-related brain regions may play an important role in the pathogenesis of PSD.t-PA reduced the expression of proBDNF and its receptor p75NTR in neurons emotion-related brain regions and significantly improved the stress-induced depression-like behavior. Therefore, it is reasonable to assume that exogenous injection of t-PA may alleviate the depressive symptoms of PSD patients.Reducing the expression of proBDNF by injecting t-PA may provide a novel therapeutic approach for the treatment of stress-related mood disorders.

A promising frontier: targeting NETs for stroke treatment breakthroughs

Stroke is a prevalent global acute cerebrovascular condition, with ischaemic stroke being the most frequently occurring type. After a stroke, neutrophils accumulate in the brain and subsequently generate and release neutrophil extracellular traps (NETs). The accumulation of NETs exacerbates the impairment of the blood‒brain barrier (BBB), hampers neovascularization, induces notable neurological deficits, worsens the prognosis of stroke patients, and can facilitate the occurrence of t-PA-induced cerebral haemorrhage subsequent to ischaemic stroke. Alternative approaches to pharmacological thrombolysis or endovascular thrombectomy are being explored, and targeting NETs is a promising treatment that warrants further investigation.

Platelet-Neutrophil Association in NETs-Rich Areas in the Retrieved AIS Patient Thrombi

Histological structure of thrombi is a strong determinant of the outcome of vascular recanalization therapy, the only treatment option for acute ischemic stroke (AIS) patients. A total of 21 AIS patients from this study after undergoing non-enhanced CT scan and multimodal MRI were treated with mechanical stent-based and manual aspiration thrombectomy, and thromboembolic retrieved from a cerebral artery. Complementary histopathological and imaging analyses were performed to understand their composition with a specific focus on fibrin, von Willebrand factor, and neutrophil extracellular traps (NETs). Though distinct RBC-rich and platelet-rich areas were found, AIS patient thrombi were overwhelmingly platelet-rich, with 90% of thrombi containing <40% total RBC-rich contents (1.5 to 37%). Structurally, RBC-rich areas were simple, consisting of tightly packed RBCs in thin fibrin meshwork with sparsely populated nucleated cells and lacked any substantial von Willebrand factor (VWF). Platelet-rich areas were structurally more complex with thick fibrin meshwork associated with VWF. Plenty of leukocytes populated the platelet-rich areas, particularly in the periphery and border areas between platelet-rich and RBC-rich areas. Platelet-rich areas showed abundant activated neutrophils (myeloperoxidase+ and neutrophil-elastase+) containing citrullinated histone-decorated DNA. Citrullinated histone-decorated DNA also accumulated extracellularly, pointing to NETosis by the activated neutrophils. Notably, NETs-containing areas showed strong reactivity to VWF, platelets, and high-mobility group box 1 (HMGB1), signifying a close interplay between these components.

Trends of Acute Ischemic Stroke Reperfusion Therapies from 2012 to 2016 in the United States

BACKGROUND

American Heart Association/American Stroke Association guidelines recommend endovascular stroke therapy (EST) with recombinant tissue plasminogen activator (rt-PA) for eligible patients in acute ischemic stroke (AIS). Using the National Inpatient Sample database, we evaluated trends in treatment with rt-PA and EST for AIS and their outcomes.

METHODS

This is a cross-sectional observational study of patients with AIS admitted in US hospitals from 2012 to 2016. Patients were grouped into those who received rt-PA alone, EST alone, and rtPA+EST. Survey statistical procedures were performed. Multivariable regression analysis with pairwise comparisons of each treatment group with no treatment group was performed for discharge outcomes.

RESULTS

The study included 2,290,520 patients with AIS with the mean age of 70.46 years. Treatment rates increased from 2012 to 2016 for rt-PA by 7% per year (5.86%-7.67%, odds ratio [OR] = 1.07, 95% confidence interval [CI]: 1.05-1.08) and EST by 38% per year (0.55%-1.75%, OR = 1.38, 95% CI: 1.31-1.45) but not rt-PA+EST (0.54%-0.57%, OR = 1.04, 95% CI: 0.99-1.08). The mean length of stay reduced from 2012 to 2016 for rt-PA (6.07-4.91 days, P < 0.0001) and rt-PA+EST (9.19-7.10 days, P = 0.0067) but not for EST (9.61-8.51 days, P = 0.5074). The odds of patients discharged home increased by 8%, 9%, and 15% among patients who received rt-PA alone, EST alone, and rt-PA+EST, respectively, compared with no treatment group.

CONCLUSION

The utilization of rt-PA alone and EST alone increased but that of rt-PA+EST remained unchanged from 2012 to 2016 in the National Inpatient Sample.

Identification of characteristics, risk factors, and predictors of recurrent LVAD thrombosis: conditions in HeartWare devices

Background

Redictors of repetitive left-ventricular assist device (LVAD)-thrombosis have not been studied yet.

Methods

We identified predictors of recurrent LVAD thrombosis in HeartWare (HVAD) patients in a long-term study from 2010 until 2020. We included all patients with two or more thrombolysis treatments for repetitive HVAD thrombosis and effectiveness of thrombolytic therapy was defined as freedom from stroke, death, another HVAD thrombosis, or surgical device exchange within 30 days after the event. Study endpoints also include all-cause mortality and heart transplantation.

Results

A total of 534 HVAD implantations have been screened, and 73 patients (13.7%) developed first HVAD thrombosis after a median of 10 months (IQR; 6–21 months). 46 of these patients had effective thrombolysis in 71.7% (n = 33/46). After a median of 14 months (IQR 4–32 months) follow-up, 17 patients (51.5%) had developed a second HVAD thrombosis and all were treated with t-PA therapy again, resulting in effectiveness in 76.5% (n = 13/17). The four patients with ineffective t-PA therapy underwent subsequent surgical HVAD exchange. Multiple Cox regression model analysis revealed time interval between HVAD implantation and first thrombosis as an independent risk factor of recurrent thrombosis (HR, 0.93, 95% CI 0.87–0.99, p = 0.031). Kaplan–Meier analysis at 3 year follow-up showed no significant difference in overall survival for recurrent vs non-recurrent thrombosis groups (log-rank test, p = 0.959).

Conclusion

Recurrent HVAD thrombosis mostly appears within 12 months after first thrombosis. Systemic t-PA therapy for recurrent pump thrombosis seems safe, achieving comparable effectiveness rates to initial t-PA therapy. Survival does not differ between patients with or without recurrent HVAD thrombosis.

Cannabidiol Ameliorates Monocrotaline-Induced Pulmonary Hypertension in Rats

Cannabidiol (CBD) is known for its vasorelaxant (including in the human pulmonary artery), anti-proliferative and anti-inflammatory properties. The aim of our study was to examine the potential preventive effect of chronic CBD administration (10 mg/kg/day for three weeks) on monocrotaline (MCT)-induced pulmonary hypertension (PH) rats. PH was connected with elevation of right ventricular systolic pressure; right ventricle hypertrophy; lung edema; pulmonary artery remodeling; enhancement of the vasoconstrictor and decreasing vasodilatory responses; increases in plasma concentrations of tissue plasminogen activator, plasminogen activator inhibitor type 1 and leukocyte count; and a decrease in blood oxygen saturation. CBD improved all abovementioned changes induced by PH except right ventricle hypertrophy and lung edema. In addition, CBD increased lung levels of some endocannabinoids (anandamide, N-arachidonoyl glycine, linolenoyl ethanolamide, palmitoleoyl ethanolamide and eicosapentaenoyl ethanolamide but not 2-arachidonoylglycerol). CBD did not affect the cardiopulmonary system of control rats or other parameters of blood morphology in PH. Our data suggest that CBD ameliorates MCT-induced PH in rats by improving endothelial efficiency and function, normalization of hemostatic alterations and reduction of enhanced leukocyte count determined in PH. In conclusion, CBD may be a safe, promising therapeutic or adjuvant therapy agent for the treatment of human pulmonary artery hypertension.

Inter-hospital transfer for mechanical thrombectomy within the supraregional stroke network NEVAS

Background

Telemedicine stroke networks are mandatory to provide inter-hospital transfer for mechanical thrombectomy (MT). However, studies on patient selection in daily practice are sparse.

Methods

Here, we analyzed consecutive patients from 01/2014 to 12/2018 within the supraregional stroke network “Neurovascular Network of Southwest Bavaria” (NEVAS) in terms of diagnoses after consultation, inter-hospital transfer and predictors for performing MT. Degree of disability was rated by the modified Rankin Scale (mRS), good outcome was defined as mRS ≤ 2. Successful reperfusion was assumed when the modified thrombolysis in cerebral infarction (mTICI) was 2b-3.

Results

Of 5722 telemedicine consultations, in 14.1% inter-hospital transfer was performed, mostly because of large vessel occlusion (LVO) stroke. A total of n = 350 patients with LVO were shipped via NEVAS to our center for MT. While n = 52 recanalized spontaneously, MT-treatment was performed in n = 178 patients. MT-treated patients had more severe strokes according to the median National institute of health stroke scale (NIHSS) (16 vs. 13, p < 0.001), were more often treated with intravenous thrombolysis (64.5% vs. 51.7%, p = 0.026) and arrived significantly earlier in our center (184.5 versus 228.0 min, p < 0.001). Good outcome (27.5% vs. 30.8%, p = 0.35) and mortality (32.6% versus 23.5%, p = 0.79) were comparable in MT-treated versus no-MT-treated patients. In patients with middle cerebral artery occlusion in the M1 segment or carotid artery occlusion good outcome was twice as often in the MT-group (21.8% vs. 12.8%, p = 0.184). Independent predictors for performing MT were higher NIHSS (OR 1.096), higher ASPECTS (OR 1.28), and earlier time window (OR 0.99).

Conclusion

Within a telemedicine network stroke care can successfully be organized as only a minority of patients has to be transferred. Our data provide clinical evidence that all MT-eligible patients should be shipped with the fastest transportation modality as possible.

The use of thromboelastography to assess post-operative changes in coagulation and predict graft function in renal transplantation

BACKGROUND

End stage renal disease (ESRD) is associated with elevated fibrinogen levels and fibrinolysis inhibition. However, there is a paucity of data on how renal transplantation impacts coagulation. we hypothesize that renal transplantation recipients with good functioning grafts will have improved fibrinolytic activity following surgery.

METHODS

Kidney recipients were analyzed pre-operatively and on post-operative day 1(POD1) using three different TEG assays with and without two concentration of tissue-plasminogen activator (t-PA). TEG indices and percent reduction in creatinine from pre-op to POD1 were measured, with >50% defining "good" graft function. Follow up was done at 6, 12, and 24 months.

RESULTS

Percent lysis(LY30) on POD1 the t-PA TEG was significantly correlated to change creatinine from pre-op to POD-1(p = 0.006). A LY30 ≥ 23% was associated with good early graft function, and lower creatinine at 24-months(p = 0.028) compared to recipients with low POD1 LY30.

CONCLUSIONS

Post-operative tPA-TEG LY30 is associated with favorable early and late outcomes in kidney transplant.

Sex and racial disparity in utilization and outcomes of t-PA and thrombectomy in acute ischemic stroke

BACKGROUND/PURPOSE

Racial/ethnic and sex disparity may occur in stroke throughout the continuum of care. Endovascular therapy (EVT) became standard of care in 2015 for eligible patients with acute ischemic stroke (AIS). We evaluated for racial and sex differences in t-PA and EVT utilization and outcomes in 2016 in the National Inpatient Sample.

METHODS

Treatment rates for t-PA, EVT, and t-PA+EVT and outcomes including home discharge, in-hospital mortality and prolonged length of stay (pLOS) were evaluated by sex and race. Multivariate survey-logistic regression was performed to evaluate outcomes.

RESULTS

The study had 468,630 patients - 49.3% men, 50.7% women; 69.3% whites, and 30.7% non-whites. There was no difference in treatment utilization by sex, women vs men for t-PA (7.65% vs 7.76%; aOR:1.02; 95% CI:0.97-1.07), EVT (1.74% vs 1.67%; aOR:1.09; 95% CI:0.99-1.20) and t-PA+EVT (0.57% vs 0.57%; aOR:1.01; 95% CI:0.85-1.21); and by race, non-white vs white for t-PA (7.62% vs 7.74%; aOR:0.98; 95% CI:0.93-1.05), EVT (1.62% vs 1.74%; aOR:0.91; 95% CI:0.78-1.07), and t-PA+EVT(0.59% vs 0.56%; aOR:1.05; 95% CI:0.84-1.30). Compared to men, women treated with t-PA had less home discharge (37.2% vs 46.3%; aOR:0.81; 95% CI:0.72-0.90), more in-hospital mortality (5.7% vs 3.9%; aOR:1.37; 95% CI:1.06-1.77) and less pLOS (8.3% vs 9.6%; aOR:0.82; 95% CI:0.69-0.98); women treated with EVT had less home discharge (15.8% vs 23.7%; aOR:0.69; 95% CI:0.52-0.91). Compared to whites, non-whites treated with t-PA had lower odds of home discharge (42.1% vs 41.6%; aOR:0.79; 95% CI:0.69-0.90), less in-hospital mortality (3.7% vs 5.3%; aOR:0.65; 95% CI:0.49-0.87), and higher pLOS (11.4% vs 7.9%; aOR:1.3; 95% CI:1.07-1.56); non-whites treated with EVT had less home discharge (18%vs 20.2%; aOR:0.70; 95% CI:0.51-0.97) and higher pLOS (35.1% vs 24%; aOR:1.52; 95% CI:1.16-1.99).

CONCLUSION

Sex and racial disparity exists for outcomes of t-PA and EVT despite no difference in utilization rates.

Glutamate controls vessel-associated migration of GABA interneurons from the pial migratory route via NMDA receptors and endothelial protease activation

During cortex development, fine interactions between pyramidal cells and migrating GABA neurons are required to orchestrate correct positioning of interneurons, but cellular and molecular mechanisms are not yet clearly understood. Functional and age-specific expression of NMDA receptors by neonate endothelial cells suggests a vascular contribution to the trophic role of glutamate during cortical development. Associating functional and loss-of-function approaches, we found that glutamate stimulates activity of the endothelial proteases MMP-9 and t-PA along the pial migratory route (PMR) and radial cortical microvessels. Activation of MMP-9 was NMDAR-dependent and abrogated in t-PA-/- mice. Time-lapse recordings revealed that glutamate stimulated migration of GABA interneurons along vessels through an NMDAR-dependent mechanism. In Gad67-GFP mice, t-PA invalidation and in vivo administration of an MMP inhibitor impaired positioning of GABA interneurons in superficial cortical layers, whereas Grin1 endothelial invalidation resulted in a strong reduction of the thickness of the pial migratory route, a marked decrease of the glutamate-induced MMP-9-like activity along the PMR and a depopulation of interneurons in superficial cortical layers. This study supports that glutamate controls the vessel-associated migration of GABA interneurons by regulating the activity of endothelial proteases. This effect requires endothelial NMDAR and is t-PA-dependent. These neurodevelopmental data reinforce the debate regarding safety of molecules with NMDA-antagonist properties administered to preterm and term neonates.

Utilization of Intravenous Tissue Plasminogen Activator and Reasons for Nonuse in Acute Ischemic Stroke in Saudi Arabia

BACKGROUND

Recombinant tissue plasminogen activator (rt-PA, alteplase) within 4.5 hours of symptom onset decreases the rate of disability after acute ischemic stroke (AIS). Due to various reasons, alteplase remains underutilized in certain regions (∼3% in low- and middle-income countries).

AIMS

We aimed to estimate the alteplase utilization rate and identify the reasons for nonuse in Saudi Arabia.

METHODS

We retrospectively reviewed all patients admitted with suspected stroke in the past 24 hours to the stroke unit at King Abdulaziz Medical City, Riyadh, Saudi Arabia from February 2016 to July 2018. We estimated the alteplase utilization rate among patients with AIS who could be treated within 4.5 hours of symptoms onset (≤225 minutes, allowing 45 minutes for door to needle time). We examined potential predictors of alteplase use using multivariable logistic regression analyses. Study was approved by local IRB.

RESULTS

Of 1366 patients with suspected stroke, 819 (60%) had AIS. The alteplase utilization rates were 8.6% and 29% for all AIS and AIS arrived within the therapeutic window, respectively. The most common reason for no alteplase treatment was late arrival. Only 244 (29.8%) of AIS patients arrived within the time window for treatment. Among patients with sudden neurological deficit who arrived within the therapeutic time window, the most common reasons were mild neurological deficit (National Institutes of Health Stroke Scale score <5, 29.9%), stroke mimics (16.6%), and hemorrhagic stroke (8.1%).

CONCLUSIONS

Our study showed a comparable alteplase utilization rate with most international estimates. The low utilization rate was mainly attributed to late patient arrival. Urgent interventions are needed to improve public awareness of stroke recognition and prehospital stroke care.

[VEGF-A therapeutic target against hemorrhagic transformation after t-PA treatment]

Tissue plasminogen activator (t-PA) treatment is beneficial for patients with ischemic stroke within 4.5 h of stroke onset, because the risk of intracerebral hemorrhagic transformation (HT) increases with delayed t-PA treatment. The benefits of t-PA thrombolysis are heavily dependent on time to treatment. Development of vasoprotective drugs that attenuate HT after delayed t-PA treatment might improve the prognosis of stroke patients and extend the therapeutic time window of t-PA and endovascular thrombolysis. An angiogenic factor, vascular endothelial growth factor (VEGF), might be associated with the blood-brain barrier (BBB) disruption after focal cerebral ischemia. By using a rat thromboembolic model, delayed t-PA treatment at 4 h after ischemia promoted expression of VEGF in BBB, matrix metalloproteinase-9 (MMP-9) activation, degradation of BBB components, and HT. We demonstrated that HT was inhibited by intravenous administration of an anti-VEGF neutralizing antibody/VEGF receptor antagonist. In addition, for clinical application, reverse translation studies, a path from bedside to bench, are necessary.

Biological effect of tissue plasminogen activator (t-PA) and DNase intrapleural delivery in pleural infection patients

Background

Pleural infection (PI) is a major global disease with an increasing incidence, and pleural fluid (PF) drainage is essential for the successful treatment. The MIST2 study demonstrated that intrapleural administration of tissue plasminogen activator (t-PA) and DNase, or t-PA alone increased the volume of drained PF. Mouse model studies have suggested that the volume increase is due to the interaction of the pleura with the t-PA via the monocyte chemoattractant protein 1 (MCP-1) pathway. We designed a study to determine the time frame of drained PF volume induction on intrapleural delivery of t-PA±DNase in humans, and to test the hypothesis that the induction is mediated by the MCP-1 pathway.

Methods

Data and samples from the MIST2 study were used (210 PI patients randomised to receive for 3 days either: t-PA and DNase, t-PA and placebo, DNase and placebo or double placebo). PF MCP-1 levels were measured by ELISA. One-way and two-way analysis of variance (ANOVA) with Tukey's post hoc tests were used to estimate statistical significance. Pearson's correlation coefficient was used to assess linear correlation.

Results

Intrapleural administration of t-PA±DNase stimulated a statistically significant rise in the volume of drained PF during the treatment period (days 1-3). No significant difference was detected between any groups during the post-treatment period (days 5-7). Intrapleural administration of t-PA increased MCP-1 PF levels during treatment; however, no statistically significant difference was detected between patients who received t-PA and those who did not. PF MCP-1 expression was not correlated to the drug given nor the volume of drained PF.

Conclusions

We conclude that the PF volume drainage increment seen with the administration of t-PA does not appear to act solely via activation of the MCP-1 pathway.

[Endovascular therapy for acute stroke-An important role of neurologists]

Previous randomized clinical trials have revealed significant benefit of the endovascular thrombectomy for the patients with acute ischemic stroke. In this short communication, I would like to introduce the history of endovascular treatment for acute ischemic stroke in Japan, and give a positive message to the neurologists who might contribute to the treatment for acute ischemic stroke.

t-PA Suppresses the Immune Response and Aggravates Neurological Deficit in a Murine Model of Ischemic Stroke

Introduction: Acute ischemic stroke (AIS) is a potent trigger of immunosuppression, resulting in increased infection risk. While thrombolytic therapy with tissue-type plasminogen activator (t-PA) is still the only pharmacological treatment for AIS, plasmin, the effector protease, has been reported to suppress dendritic cells (DCs), known for their potent antigen-presenting capacity. Accordingly, in the major group of thrombolyzed AIS patients who fail to reanalyze (>60%), t-PA might trigger unintended and potentially harmful immunosuppressive consequences instead of beneficial reperfusion. To test this hypothesis, we performed an exploratory study to investigate the immunomodulatory properties of t-PA treatment in a mouse model of ischemic stroke.

Methods: C57Bl/6J wild-type mice and plasminogen-deficient (plg^−/−) mice were subjected to middle cerebral artery occlusion (MCAo) for 60 min followed by mouse t-PA treatment (0.9 mg/kg) at reperfusion. Behavioral testing was performed 23 h after occlusion, pursued by determination of blood counts and plasma cytokines at 24 h. Spleens and cervical lymph nodes (cLN) were also harvested and characterized by flow cytometry.

Results: MCAo resulted in profound attenuation of immune activation, as anticipated. t-PA treatment not only worsened neurological deficit, but further reduced lymphocyte and monocyte counts in blood, enhanced plasma levels of both IL-10 and TNFα and decreased various conventional DC subsets in the spleen and cLN, consistent with enhanced immunosuppression and systemic inflammation after stroke. Many of these effects were abolished in plg^−/− mice, suggesting plasmin as a key mediator of t-PA-induced immunosuppression.

Conclusion: t-PA, via plasmin generation, may weaken the immune response post-stroke, potentially enhancing infection risk and impairing neurological recovery. Due to the large number of comparisons performed in this study, additional pre-clinical work is required to confirm these significant possibilities. Future studies will also need to ascertain the functional implications of t-PA-mediated immunosuppression for thrombolyzed AIS patients, particularly for those with failed recanalization.

Acute carotid stent thrombosis

Carotid artery stenting is a method used in the treatment of extracranial carotid artery stenosis that is becoming increasingly more common. Acute carotid thrombosis following CAS is a very rare and devastating complication that can be lethal for the patient unless treated immediately. We report a case of acute carotid stent thrombosis occurring immediately after emergent revascularization, and that was treated with intraarterial tissue plasminogen activator and intravenous tirofiban infusion.

Simvastatin pretreatment ameliorates t-PA-induced hemorrhage transformation and MMP-9/TIMP-1 imbalance in thromboembolic cerebral ischemic rats

Background: The use of thrombolysis with tissue-plasminogen activator (t-PA) in patients with acute ischemic stroke (AIS) is limited by increased levels of matrix metalloproteinase-9 (MMP-9) and by the increased risk of hemorrhagic transformation (HT). In this study, we investigated the effects of simvastatin pretreatment on t-PA-induced MMP-9/tissue inhibitor of metalloproteinase-1 (TIMP-1) imbalance and HT aggravation in a rat AIS model. Methods: The rat AIS model was established by autologous blood emboli. Two weeks before surgery, rats were pretreated with simvastatin (60 mg/kg/d), and three hours after surgery, t-PA (10 mg/kg) was administered. MMP-9 and TIMP-1 levels in the infarcted zone and plasma were evaluated by Western blot analysis and ELISA; the level of HT was quantified by determining the hemoglobin content. RhoA activation was determined to clarify the potential effect. Results: The results suggested that pretreatment with simvastatin suppressed the increase in t-PA-induced MMP-9 levels and neutralized the elevated MMP-9/TIMP-1 ratio, but had no effect on TIMP-1 levels. Thrombolysis with t-PA after ischemia improved neurological outcome, but increased intracranial hemorrhage. Moreover, t-PA-induced HT aggravation was reduced by simvastatin pretreatment. In addition, we showed that t-PA-induced activation of RhoA was suppressed by simvastatin, and that t-PA-induced MMP-9/TIMP-1 imbalance and hemorrhage was reduced by Rho kinases (ROCK) inhibitor Y-27632. Conclusion: In this study, we showed that simvastatin pretreatment ameliorated t-PA-induced HT and MMP-9/TIMP-1 imbalance, and demonstrated that the RhoA/ROCK pathway was implicated.

Fibrinolytic System Changes in Liver Surgery: A Pilot Observational Study

Introduction: Bleeding occurs frequently in liver surgery. Unbalance between tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) concentrations might increase bleeding. Our aim was to analyze perioperative fibrinolytic changes during liver surgery.

Materials and Methods: We evaluated 15 patients for inclusion into a prospective pilot study of liver surgery. We assessed fibrinolysis by plasma PAI-1 and t-PA: before surgery (T1), before Pringle maneuver (PM;T2), at the end of surgery (T3) and 24 h postoperatively (T4), and registered demographic and laboratory data, extent and duration of surgery, hemodynamic parameters, blood loss, and transfused volumes of blood products. Data presented as mean ± SD. Significance at P < 0.05.

Results: After exclusion of six patients only undergoing biopsies, we included six women and three men aged 49.1 ± 19.6 years; two patients with liver metastases of colorectal cancer and hepatocellular carcinoma, respectively, two with focal nodular hyperplasia, two with hepatic hemangioma, and one with angiomyolipoma. Six patients underwent PM. PAI-1 plasma concentration (n = 9) rose from 6.25 ± 2.25 at T1 through 17.30 ± 14.59 ng/ml at T2 and 28.74 ± 20.4 (p = 0.007) and 22.5 ± 16.0 ng/ml (p = 0.04), respectively, at T3 and T4. Correspondingly, t-PA plasma concentration (n = 9) increased from 4.76 ± 3.08 ng/ml at T1 through 8.00 ± 5.10 ng/ml (p = 0.012) at T2 and decreased to 4.25 ± 2.29 ng/ml and 3.04 ± 3.09 at T3 and T4, respectively. Plasma t-PA level at T2 was significantly different from those at T1, T3, and T4 (p < 0.004). In PM patients, t-PA levels increased from T1, peaked at T2 (p = 0.001), and subsequently decreased at T3 and T4 (p = 0.011 and p = 0.037), respectively. Mean blood loss was 1,377.7 ± 1,062.8 ml; seven patients received blood products. Patients with higher PAI-1 levels at T3 received more fresh frozen plasma (r = 0.79; p = 0.01) and red blood cells (r = 0.88; p = 0.002).

Conclusions: During liver surgery, fibrinolysis increased, as evidenced by rises in plasma PAI-1and t-PA, especially after start of surgery and following PM. Transfused volumes of blood products correlated with higher plasma concentrations of PAI-1. Confirming this tendency requires a larger cohort of patients.

Changes in spontaneous thrombolytic activity during progression of atherosclerosis in Apo-/- and LDLR-/- double knockout mice

BACKGROUND

Atherosclerosis is characterized by a hypercoagulable state, during which both coagulation and thrombolytic factors are activated simultaneously. However, details regarding the thrombolytic pathway in this context remain unknown. Here we investigated the changes in spontaneous thrombolytic activity during atherosclerotic progression in Apo-/-LDLR-/- double-knockout mice (DKO group).

METHODS

We fed DKO mice and their controls (C57Bl6 mice) a high-fat diet for a total of 22 weeks and evaluated them at 14 and 22 weeks. The amount of atherosclerosis was estimated as the ratio of the atherosclerotic to total aortic intimal area. In addition, we used immunohistochemistry to analyze the expression of PAI-1, t-PA, and eNOS in atherosclerotic regions. To evaluate thrombolysis, we used a He-Ne laser to induce thrombosis in vessels of the cremaster muscle and then measured the thrombus volume over time.

RESULTS

The atherosclerotic area was increased and thrombolytic activity was decreased in DKO group compared with the control group. Furthermore, the plasma PAI-1 level was 3 times greater in the DKO group than in the control group. In support of these results, immunohistochemistry showed increased PAI-1 expression in the DKO group, whereas t-PA and eNOS expression was greater in the control group.

CONCLUSION

Progression of atherosclerosis led to a reduction in thrombolytic activity through decreases in t-PA and eNOS levels and an increase in PAI-1 production. These findings indicate that decreases in factors that promote spontaneous thrombolytic activity may indicate increased risk for the progression of atherosclerosis.

A Case of Rapid Malignant Brain Swelling Subacutely After Reperfusion Therapy for Internal Carotid Artery Occlusion

BACKGROUND

Severe complications after reperfusion therapy for acute major vessel occlusion are not well described. We present an extremely rare case of a patient with rapid malignant brain swelling subacutely after acute ischemic stroke.

CASE DESCRIPTION

An 84-year-old man underwent reperfusion therapy for acute left internal carotid artery occlusion; complete reperfusion was achieved. Although magnetic resonance imaging on postoperative day 1 revealed a small hemorrhagic infarction and subarachnoid hemorrhage unrelated to a left middle cerebral artery aneurysm in the left frontal lobe, neurologic deficits resolved completely. On postoperative day 5, the patient developed a fever and sudden disorder of consciousness with right hemiparesis. Urosepsis was diagnosed, and computed tomography revealed massive hemorrhagic infarction in the left frontal lobe and diffuse subarachnoid hemorrhage. Emergent hematoma evacuation and clipping were performed. Although the aneurysm was unruptured, brain swelling was severe despite a patent middle cerebral artery. Computed tomography performed immediately postoperatively (within 6 hours after preoperative computed tomography) showed severe left brain swelling with midline shift. The patient died on postoperative day 15.

CONCLUSIONS

This case has similarities to both second-impact syndrome after head trauma and perfusion breakthrough phenomenon. Initial ischemic damage following reperfusion therapy and damage secondary to sepsis and subarachnoid hemorrhage may have led to rapid malignant brain swelling in this patient. Careful management is important for patients receiving reperfusion therapy.

Effects of hemocoagulase agkistrodon on the coagulation factors and its procoagulant activities

Objective

Hemocoagulase agkistrodon (HCA), a thrombin-like enzyme (TLE) from the venom of the Chinese moccasin snake (Deinagkistrodon acutus), has been used in clinical practice as a hemostatic compound. The aim of this study was to further investigate the pharmacological properties of HCA.

Materials and methods

Sodium dodecyl sulfate or native polyacrylamide gel electrophoresis (SDS- or N-PAGE) as well as enzyme linked immunosorbent assays (ELISAs) were conducted to study the effects of HCA on the human plasma fibrinogen and prothrombin levels, as well as its in vitro interactions with some coagulation factors. In addition, the bleeding time effects of HCA in the mouse tail-bleeding model as well as its effects on the fibrinogen levels in rabbits were determined in vivo.

Results

In vitro results revealed that HCA exerts its procoagulant activities by hydrolyzing fibrinogen into segments that are easier to be absorbed, reducing the risk of thrombus formation. Besides, HCA could significantly inhibit the activation of prothrombin at the concentration of 0.3 μM. Unexpectedly, we also found that HCA was able to strongly bind to factor X/Xa (in a ratio of 1:1) and thus inhibit the acceleration of active factor X to tissue plasminogen activator-catalyzed plasminogen activation, demonstrating that it could be less likely to lead to thrombus formation. Finally, in vivo results indicated that HCA could significantly shorten the bleeding time in the mouse tail-bleeding model and had no effect on the fibrinogen levels in rabbits.

Conclusion

In summary, HCA, a unique and new family member of TLEs, may become a new clinical drug for the prevention and treatment of hemorrhage due to its unique and complex interactions with the blood system. Clarification of these features will enable us to further understand the mechanism of action of HCA and then promote its further application in clinical practice as a therapeutic drug.

Danhong Injection Combined With t-PA Improves Thrombolytic Therapy in Focal Embolic Stroke

Background: Hemorrhagic transformation, neurotoxicity, short treatment time windows, and other defects are considered as the major limitations for the thrombolytic therapy. This study is devoted to figure out whether Danhong injection (DHI) combined with tissue-plasminogen activator (t-PA) could extend the treatment time windows and ameliorate brain injury, hemorrhagic complication and BBB disruption after focal embolic stroke. Methods:In vitro, the combined concentrations of DHI and t-PA were added to wells reacted with plasminogen and D-Val-Leu-Lys-AMC. The optimum ratio of the combination of DHI plus t-PA was explored by detecting relative fluorescent. In vivo experiments, we firstly investigated the optimal dose of t-PA and Danhong injection for focal embolic stroke. The neurological deficit score, infarct volume and brain edema were assessed. Secondly, we proved that the combination group extended the thrombolytic window for treatment of focal embolic stroke. The neurological deficit score, infarct volume, brain edema and hemorrhagic complication were assessed, while levels of BAX, Bcl-2 and caspase-3 in brain tissue were analyzed by real-time polymerase chain reaction. Finally, to ask whether combination therapy with DHI plus t-PA protected the blood-brain barrier in a rat model of focal embolic stroke, neurological deficit score, ELISA, RT-PCR, western blot and fluorescence were used to detect the indicators of blood-brain barrier, such as tight junction protein, blood-brain barrier permeability and related gene expression. Results:In vitro, plasmin activity assays showed that the combination of t-PA with DHI at about 1:1.6 w/v ratio increased by almost 1.4-fold the plasmin-generating capability of t-PA. In vivo experiments, the results showed that the combination of Danhong injection (4 mL/kg) and t-PA (2.5 mg/kg) could extend the t-PA treatment time windows to 4.5 h. And the combination t-PA (2.5 mg/kg) with DHI (4 mL/kg) ameliorated neurological score, cerebral infarction, brain edema, brain hemorrhage, and BBB disruption. Conclusion: Combination therapy with Danhong injection (4 mL/kg) plus t-PA (2.5 mg/kg) could extend the t-PA treatment time windows to 4.5 h, ameliorate BBB disruption, reduce infarction, brain swelling and hemorrhage after ischemic stroke.

Short-chain fatty acids induce tissue plasminogen activator in airway epithelial cells via GPR41&43

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease generally divided based on the presence or absence of nasal polyps (NPs). One of the features of NPs is excessive fibrin deposition, which is associated with down-regulation of tissue plasminogen activator (t-PA) in NPs. As t-PA is expressed in epithelial cells, and epithelium is readily accessible to topical therapies, identifying compounds that can mediate the induction of t-PA would be a potential new strategy for the treatment of NPs.

OBJECTIVE

The objective of this study was to determine whether short-chain fatty acids (SCFAs) can induce t-PA in airway epithelial cells via their known receptors GPR41 and GPR43.

METHODS

We performed immunohistochemistry (IHC) to determine whether receptors for SCFAs, known as G protein-coupled receptor 41/free fatty acid receptor 3 (GPR41/FFAR3) and GPR43/FFAR2, are expressed in nasal tissue. Primary normal human bronchial epithelial (NHBE) cells were stimulated with different concentrations of SCFAs to test induction of t-PA, which was analysed by expression of mRNA and protein. Mediation of responses by SCFA receptors was evaluated by specific receptor gene silencing with siRNA.

RESULTS

Immunohistochemistry study revealed that airway epithelial cells expressed GPR41 and GPR43. Acetic acid, propionic acid, butyric acid and valeric acid significantly induced t-PA expression from two- to tenfolds. The strongest inducer of t-PA from NHBE cells was propionic acid; cells stimulated with propionic acid released t-PA into the supernatant in its active form. Gene silencing of GPR41 and GPR43 revealed that induction of t-PA by SCFAs was dependent upon both GPR41 and GPR43.

CONCLUSIONS AND CLINICAL RELEVANCE

Short-chain fatty acids were shown to induce airway epithelial cell expression of t-PA via GPR41 and GPR43. Topical delivery of potent compounds that activate these receptors may have value by reducing fibrin deposition and shrinking nasal polyp growth.

A new assay for global fibrinolysis capacity (GFC): Investigating a critical system regulating hemostasis and thrombosis and other extravascular functions

For many years, the importance of fibrinolysis has been recognized, first for its intravascular antithrombotic action, and more recently for its many extravascular activities, associated with matrix degradation and tissue remodeling. In the blood circulation system, fibrinolysis prevents thrombosis, and is associated with various biological and clinical situations: risk factors for cardio-vascular diseases in high risk clinical situations (type II diabetes, hypertension, triglycerides, high BMI, elevated glucose, etc.), probably resulting from a significant reduction of the fibrinolysis potential, and elevation of PAI-1. Noteworthy, t-PA is mainly present as an inactive complex with PAI-1, and its concentration in plasma tends to follow that of PAI-1, but in a lesser extent. Hypofibrinolysis can favor the occurrence of thrombotic events, and possibly other biological dysfunctions. Fibrinolysis activity is however difficult to evaluate as it has a delayed activity after clot formation, is initiated and regulated after fibrin generation, and conversely to clotting, its action is delayed (long lag phase) and slow, before being dramatically amplified leading to rapid clot dissolution. We have designed a new assay for evaluating the global fibrinolytic capacity (GFC) in the body. Reagents are used in association with a specific instrument, which can be connected to any computer, and dedicated software is used for analyzing clot lysis kinetics. The assay is performed in a micro-cuvette, introduced into one of the instrument wells at 37 °C, and light transmittance is continuously measured. Assayed plasma is first supplemented with a limited and constant amount of t-PA with silica and is then clotted with thrombin and calcium. Clot dissolution (measurement of turbidity change) is recorded over time using the dedicated instrument (Lysis Timer), and clot lysis kinetics are analyzed with the associated software: primary and secondary derivatives of the light transmission curve give information on kinetics and completion of clot dissolution. Total assay time is about 1 h (but in the presence of hypofibrinolysis it can be prolonged). The concentration of t-PA used for the assay has been adjusted (100 ng/ml) to obtain an optimal sensitivity to hypofibrinolysis within a short time interval, and clot dissolution occurs within about 45 min for normal individuals, with a broad range from 30 min to 60 min, with some samples presenting a clot dissolution time >60 min (hypofibrinolysis). This new assay is performed with the tested plasma intrinsic factors, especially its own fibrinogen, and only exogeneous t-PA is added. GFC is highly sensitive to PAI-1 activity, but other factors regulating fibrinolysis contribute to the clot dissolution kinetics. Freshly prepared or frozen and thawed citrated plasma can be used. The usefulness of this assay for clinical applications is under investigation. Although fibrinolysis is mainly initiated in the body upon stimulation or blood clotting, and rapidly diluted and inhibited in the circulation, evaluation of its "residual" activity in plasma is expected to reflect its global body potential.

Safety and Time Course of Drip-and-Ship in Treatment of Acute Ischemic Stroke

BACKGROUND

The drip-and-ship approach allows intravenous tissue plasminogen activator therapy and adjuvant endovascular treatment in acute ischemic stroke, even in rural areas. Here, we examined the safety and time course of the drip-and-ship approach.

METHODS

Fifty consecutive cases treated with the drip-and-ship approach (drip-and-ship group) in June 2009 to March 2016 were retrospectively examined. Changes in mean blood pressure, systemic complications, and neurological complications were compared according to method of transportation. Time courses were compared between drip-and-ship and direct admission groups during the same period.

RESULTS

In the drip-and-ship group, 33 and 17 patients were transferred to hospital by ambulance and helicopter, respectively. One patient suffered hemorrhagic infarction during transportation by ambulance. Mean blood pressure change was lower in patients transferred by helicopter than ambulance (<5 mmHg versus 12.2 mmHg, respectively). The mean onset-to-door times in the drip-and-ship and direct admission groups were 71 and 64 minutes, respectively, and mean door-to-needle times were 70 and 47 minutes, respectively (P =.002). Although mean transportation time from the primary stroke hospital to our hospital was 32 minutes, the entry-to-exit time from the primary stroke hospital was 113 minutes. Thereafter, there was an average delay of 100 minutes until reperfusion compared with the direct admission group.

CONCLUSIONS

Drip-and-ship was relatively safe in this small series. Transportation by helicopter was less stressful for acute ischemic stroke patients. It is important to reduce door-to-needle time and needle-to-departure time in the primary stroke hospital to minimize the time until treatment in cases of acute ischemic stroke.

Regulatory effects of estetrol on the endothelial plasminogen pathway and endothelial cell migration

BACKGROUND

Estetrol (E4) is a natural estrogen produced solely during human pregnancy. E4 is suitable for clinical use since it acts as a selective estrogen receptor modulator. In clinical trials E4 has been seen to have little or no effect on coagulation. Hence, it is interesting to investigate whether E4 alters endothelial-dependent fibrinolysis.

OBJECTIVES

We studied the effects of E4 on the fibrinolytic system and whether this could influence the ability of endothelial cells to migrate. In addition, we compared the effects of E4 with those of 17β-estradiol (E2).

STUDY DESIGN

Human umbilical vein endothelial cells (HUVEC) were obtained from healthy women. Expression of plasminogen-activator inhibitor-1 (PAI-1), urokinase-type plasminogen activator (u-PA) and tissue plasminogen activator (t-PA) proteins was evaluated by Western blot analysis. Endothelial cell migration was studied by razor-scrape horizontal and multiwell insert systems assays.

RESULTS

E4 increased the expression of t-PA, u-PA and PAI-1 in HUVEC, but less so than did equimolar amounts of E2. The effects of E4 on t-PA, u-PA and PAI-1 were mediated by the induction of the early-immediate genes c-Jun and c-Fos. E4 in combination with E2 antagonized the effects induced by pregnancy-like E2 concentrations but did not impair the effects of postmenopausal-like E2 levels. We also found that the increased synthesis of PAI-1, u-PA and t-PA induced by E2 and E4 is important for horizontal and three-dimensional migration of HUVEC.

CONCLUSIONS

These results support the hypothesis that E4 acts as an endogenous selective estrogen receptor modulator (SERM), controlling the fibrinolytic system and endothelial cell migration.

The Association between t-PA Administration and In-Hospital Mortality following Acute Ischemic Stroke in Puerto Rican Patients

OBJECTIVE

Despite being the standard of care, thrombolytic therapy with tissue plasminogen activator (t-PA) is currently administered to only 5% of acute ischemic stroke (AIS) patients in the United States. Published scientific information regarding both the use of t-PA for AIS in Hispanic patients and its impact on short-term mortality is scarce. The objectives of this study are to investigate, among Puerto Rican patients hospitalized with AIS, the rate of t-PA administration, and the risk of in-hospital mortality in patients who received t-PA vs. those patients who did not receive t-PA.

METHODS

We performed a secondary analysis of data from patients with AIS admitted to acute care facilities throughout Puerto Rico in study years 2007, 2009, and 2011who were participating in the Puerto Rico Cardiovascular Disease Surveillance System. Multivariate logistic regression was used to determine the independent association between treatment with t-PA within 4.5 hours of symptom onset and in-hospital mortality.

RESULTS

Of the 1968 study patients hospitalized with AIS, 104 (5%) received t-PA treatment. After adjustments for demographic and clinical confounders, patients receiving t-PA had similar odds of in-hospital mortality as patients not receiving t-PA did (OR = 2.49, 95% CI = 0.81-7.66). The receipt of concomitant anticoagulation medication was independently associated with relatively lower odds of in-hospital mortality (OR = 0.42, 95% CI = 0.20-0.88). Being over 80 years of age (OR = 2.03, 95% CI = 1.13-3.68), being obese (OR = 1.88, 95% CI = 1.01-3.49), and arriving in an ambulance (OR = 3.61, 95% CI = 1.95-6.68) were all independently associated with relatively higher odds of in-hospital mortality.

CONCLUSION

Among patients hospitalized in Puerto Rico with acute ischemic stroke, t-PA treatment was not significantly associated with in-hospital mortality.

Post-operative intracranial hemorrhage related to using t-PA for declotting an occluded hemodialysis catheter: A cautionary tale

Heparin and thrombolytic agents such as tissue plasminogen activator (t-PA) are frequently used to prevent and treat occluded hemodialysis (HD) catheters. Thrombolytic agents have not been well studied for systemic effects. We present a post-operative neurosurgical patient who experienced a symptomatic intracranial hemorrhage (ICH) after t-PA was used to treat an occluded HD catheter. This case highlights that using t-PA to treat dysfunctional catheters may be associated with ICH in neurosurgical patients. Management strategies are discussed with a review of pertinent literature.

Pulsed Intra-Arterial Drug Injection during Diastolic Phase of Cardiac Function Increases Drug Efficacy by Enhancing Pharmacological Exposure of Targeted Tissues

Diastolic phase of cardiac function is associated with lower arterial flow and hence higher concentration of intra arterially injected drug is achieved at the site of injection. It is herein postulated that drugs show higher efficacy when injected during the diastolic phase of cardiac function. It is also postulated that this benefit cannot be achieved when the drug is injected with higher rates thus producing the same high concentration at the site of injection. Pulsed intra arterial injection also benefits from the delayed therapeutic effect of the decaying drug before the next shot of injection resaturates the targeted tissue. Altogether, it is estimated that diastolic time-locked pulsed intra arterial injection will increase the drug efficacy up to 1.9 times the efficacy of injected drug with conventional methods. This is significant for drugs with limited dose of administration due to their disastrous side effects like tissue plasminogen activator or chemotherapeutic drugs.

A Retrospective Cohort Study on the Use of Intravenous Thrombolysis in Stroke Mimics

BACKGROUND

The urgency of intravenous thrombolysis in acute ischemic stroke can lead to inadvertent thrombolysis of patients with nonstroke diagnoses (stroke mimics), increasing the risk of adverse events. The objectives of this study were to compare thrombolysed acute ischemic stroke and stroke mimic cases based on demographic factors, physiological parameters, radiological findings, and clinical presentation, and to evaluate the clinical implications of thrombolysing stroke mimics.

METHODS

A retrospective analysis of a single-center database of all thrombolysed strokes and mimics over a period greater than 3 years. Diagnoses were confirmed by expert consensus after a review of clinical factors and imaging. Intercohort variation was assessed using Wilcoxon rank-sum or Pearson's chi-square test.

RESULTS

The stroke mimic cohort tended to be younger (mean age 59.9 years versus 73.7 years, P < .001) and had a lower National Institutes of Health Stroke Score at presentation (mean 5.9 points versus 6.4 points, P < .01). However, the time taken from the onset of symptoms to delivery of thrombolytic drugs was longer in the mimic cohort (mean time 170 minutes versus 138 minutes, P < .01). Any differences in blood glucose (P = .07), time taken from hospital arrival to delivery of intravenous thrombolysis (P = .57), and blood pressure on admission (systolic, P = .09 and diastolic, P = .34) were not statistically significant. No adverse events were reported in the mimic cohort.

CONCLUSION

Despite similarities in clinical presentation, thrombolysed stroke mimics are of a different physiological and demographic population, and are associated with fewer adverse events compared with thrombolysed acute ischemic stroke patients.

The Role of Hemostatic Factors in Atherosclerosis in Patients with Chronic Renal Disease

Introduction:

Atherosclerotic cardiovascular disease remains the leading cause of increased morbidity and mortality observed in chronic kidney disease (CKD) patients. Endothelial dysfunction (ED) is thought to be a key initial event in the development of atherosclerosis. The aim of this study was to evaluate the potential role of hemostatic factors in atherosclerosis, thrombosis and cardiovascular complications in patients suffering from chronic renal disease.

Methods:

The study was conducted on 50 renal patients divided into two groups of equal size. Group 1 consisted of 25 patients with end-stage renal disease (ESRD) on regular hemodialysis. Group 2 consisted of 25 chronic renal disease patients on conservative treatment. Twenty age- and sex-matched healthy subjects were included in the study to serve as a control group. Thrombomodulin (TM), von Willebrand factor (vWF), tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1) and hsCRP were assessed. High-resolution B-mode ultrasonography of both the common and internal carotid arteries to measure carotid intima media thickness (CIMT) was performed on all subjects.

Results:

There were highly significant increases in hsCRP, TM, vWF, tPA and PAI-1 in both patient groups compared to the control group (P<0.01 for all except for TM between group 2 and 3 P<0.05) with significant increase in group 1 compared to group 2 (P<0.01). In addition, there was a highly significant increase in CIMT in both patient groups compared to the control group (P<0.01) with a significant increase in group 1 compared to group 2 (P<0.05). The study revealed significant positive correlation of hemostatic factors (TM, vWf, PAI-1 & t-PA) with creatinine, urea, hsCRP & CIMT.

Conclusion:

CKD patients have increased risk of atherosclerosis as measured by CIMT, which is used as a surrogate marker of early atherosclerosis and has been shown to be a strong predictor of future myocardial infarction and stroke. They have high levels of TM, vWF, tPA, PAI-1 that correlate with kidney function, hsCRP and CIMT. Therefore, these abnormalities in hemostasis may account for the increased risk of atherothrombosis in these patients. The elevated hsCRP levels and their correlation to hemostatic factors and CIMT might provide an important clue to link a systemic marker of inflammation to atherosclerosis. Further research is required to better understand the procoagulant state in patients with CKD.

The fibrinolytic system-more than fibrinolysis?

The fibrinolytic system, known for its ability to regulate the activation of the zymogen plasminogen into active plasmin, has been primarily associated with the removal of fibrin and blood clots. Tissue-type plasminogen activator, the most well-recognized plasminogen activator, was harnessed for therapeutic benefit against thromboembolic disorders more than 30 years ago, whereas inhibition of this system has been proven effective for certain bleeding disorders. However, in recent years, new and unexpected functional roles for this system have been identified mostly in relation to the central nervous system that are both unrelated and independent of fibrin degradation and clot removal. Hence, it seems reasonable to ask whether agents used to modify components or activities of the fibrinolytic system have any clinical consequences unrelated to their intended use in hemostasis. This review will provide an overview of these new features of the fibrinolytic system and will also focus on prospective considerations in the use of fibrinolytic and antifibrinolytic agents.

A systemized stroke code significantly reduced time intervals for using intravenous tissue plasminogen activator under magnetic resonance imaging screening

BACKGROUND

A stroke code can shorten time intervals until intravenous tissue plasminogen activator (IV t-PA) treatment in acute ischemic stroke (AIS). Recently, several reports demonstrated that magnetic resonance imaging (MRI)-based thrombolysis had reduced complications and improved outcomes in AIS despite longer processing compared with computed tomography (CT)-based thrombolysis.

METHODS

In January 2009, we implemented CODE RED, a computerized stroke code, at our hospital with the aim of achieving rapid stroke assessment and treatment. We included patients with thrombolysis from January 2007 to December 2008 (prestroke code period) and from January 2009 to May 2013 (poststroke code period). The IV t-PA time intervals and 90-day modified Rankin Scale (mRS) scores were collected.

RESULTS

During the observation period, 252 patients used IV t-PA under the CODE RED (MRI based: 208; CT based: 44). The remaining 71 patients (MRI based: 53; CT based: 18) received it before the implementation of our stroke code. After implementation of CODE RED, door-to-image time, door-to-needle time, and the onset-to-needle time were significantly reduced by 11, 18, and 22 minutes in MRI-based thrombolysis. Particularly, the proportion of favorable outcome (mRS score 0-2) was significantly increased (from 41.5% to 60.1%, P = .02) in poststroke than in prestroke code period in MRI-based thrombolysis. However, in ordinal regression, the presence of stroke code showed just a trend for favorable outcome (odds ratio, .99-2.87; P = .059) at 90 days of using IV t-PA after correction of age, sex, and National Institutes of Health Stroke Scale.

CONCLUSIONS

In this study, we demonstrated that a systemized stroke code shortened time intervals for using IV t-PA under MRI screening. Also, our results showed a possibility that a systemized stroke code might enhance the efficacy of MRI-based thrombolysis. In the future, we need to carry out a more detailed prospective study about this notion.

Molecular cloning of Reteplase and its expression in E. coli using tac promoter

BACKGROUND AND AIMS

This study aimed to clone and express the reteplase cDNA, a thrombolytic agent used for the treatment of acute myocardial infarction and stroke, in E. coli, utilizing tac promoter for its expression.

MATERIALS AND METHODS

Reteplase cDNA was amplified by polymerase chain reaction (PCR) with designed primers. The product was then cloned into pTZ57R plasmid. The cloned cDNA was digested out and ligated into pGEX-5x-1 expression vector. The presence of the insert was confirmed by restriction digestion. By using 0.2, 0.5 and 1 mM isopropyl beta-D thiogalactopyranoside (IPTG), expression of reteplase was induced in E. coli TOP10 cells and analyzed by SDS-PAGE.

RESULTS

Electrophoresis of PCR product and also double digested recombinant pTZ57R plasmid, also, pGEX-5x-1 vector, showed a 1068bp band of reteplase. SDS-PAGE analysis showed a 60 KDa band of protein product induced with different concentrations of IPTG.

CONCLUSION

In the present study, reteplase cDNA was successfully cloned and expressed using tac promoter. This vector will be used for the optimization of the expression of reteplase in E. coli.

Binding of tissue-type plasminogen activator to the glucose-regulated protein 78 (GRP78) modulates plasminogen activation and promotes human neuroblastoma cell proliferation in vitro

The glucose-regulated protein 78 (GRP78) is a plasminogen (Pg) receptor on the cell surface. In this study, we demonstrate that GRP78 also binds the tissue-type plasminogen activator (t-PA), which results in a decrease in K(m) and an increase in the V(max) for both its amidolytic activity and activation of its substrate, Pg. This results in accelerated Pg activation when GRP78, t-PA, and Pg are bound together. The increase in t-PA activity is the result of a mechanism involving a t-PA lysine-dependent binding site in the GRP78 amino acid sequence (98)LIGRTWNDPSVQQDIKFL(115). We found that GRP78 is expressed on the surface of neuroblastoma SK-N-SH cells where it is co-localized with the voltage-dependent anion channel (VDAC), which is also a t-PA-binding protein in these cells. We demonstrate that both Pg and t-PA serve as a bridge between GRP78 and VDAC bringing them together to facilitate Pg activation. t-PA induces SK-N-SH cell proliferation via binding to GRP78 on the cell surface. Furthermore, Pg binding to the COOH-terminal region of GRP78 stimulates cell proliferation via its microplasminogen domain. This study confirms previous findings from our laboratory showing that GRP78 acts as a growth factor-like receptor and that its association with t-PA, Pg, and VDAC on the cell surface may be part of a system controlling cell growth.

Current perspectives on the use of intravenous recombinant tissue plasminogen activator (tPA) for treatment of acute ischemic stroke

In 1995, the NINDS (National Institute of Neurological Disorders and Stroke) tPA (tissue plasminogen activator) Stroke Study Group published the results of a large multicenter clinical trial demonstrating efficacy of intravenous tPA by revealing a 30% relative risk reduction (absolute risk reduction 11%-15%) compared with placebo at 90 days in the likelihood of having minimal or no disability. Since approval in 1996, tPA remains the only drug treatment for acute ischemic stroke approved by the US Food and Drug Administration. Over the years, an abundance of research and clinical data has supported the safe and efficacious use of intravenous tPA in all eligible patients. Despite such supporting data, it remains substantially underutilized. Challenges to the utilization of tPA include narrow eligibility and treatment windows, risk of symptomatic intracerebral hemorrhage, perceived lack of efficacy in certain high-risk subgroups, and a limited pool of neurological and stroke expertise in the community. With recent US census data suggesting annual stroke incidence will more than double by 2050, better education and consensus among both the medical and lay public are necessary to optimize the use of tPA for all eligible stroke patients. Ongoing and future research should continue to improve upon the efficacy of tPA through more rapid stroke diagnosis and treatment, refinement of advanced neuroimaging and stroke biomarkers, and successful demonstration of alternative means of reperfusion.

Cloning and expression of hybrid streptokinase towards clot-specific activity

Streptokinase (SK) is a thrombolytic agent that is widely used to treat myocardial infarction and pulmonary embolism. The lack of fibrin specificity of SK for the clot lysis is one of the limitations of SK. In this study, we have incorporated the finger and Kringle 2 domains from the human tissue type plasminogen activator gene (t-PA) at the 5' end of the SK gene. These domains are responsible for specific binding to fibrin. We have used the pRSETB vector in an attempt to express the hybrid streptokinase possessing specificity for fibrin. On this regard, three hybrid streptokinase were constructed and expressed in Escherichia coli BL21 (DE3): the finger domain with SK (FSK), the Kringle 2 domain with SK (KSK) and the finger domain+Kringle 2 with SK (FKSK). The activities of the hybrid SKs were assessed by caseinolytic assay and clot lysis assay. All hybrid SKs were found to activate plasminogen in the caseinolytic plate assay. In the clot lysis assay, KSK and FSK were able to dissolute human blood and artificial clots in a fibrin-dependent manner unlike the SK and FKSK proteins.

REVASCAT: a randomized trial of revascularization with SOLITAIRE FR device vs. best medical therapy in the treatment of acute stroke due to anterior circulation large vessel occlusion presenting within eight-hours of symptom onset

REVASCAT is a prospective, multicenter, randomized trial seeking to establish whether subjects meeting following main inclusion criteria: age 18-80, baseline National Institutes of Health Stroke Scale ≥6, evidence of intracranial internal carotid artery or proximal (M1 segment) middle cerebral artery occlusion, Alberta Stroke Program Early Computed Tomography score of >7 on non-contrast CT or >6 on diffusion-weighted magnetic resonance imaging , ineligible for or with persistent occlusion after intravenous alteplase and procedure start within 8 hours from symptom onset, have higher rates of favorable outcome when treated with the Solitaire FR embolectomy device compared to standard medical therapy alone The primary end-point, based on intention-to-treat criteria is the distribution of modified Rankin Scale scores at 90 days. Projected sample size is 690 patients. Estimated common odds ratio is 1●615. Randomization is performed under a minimization process using age, baseline NIHSS, therapeutic window, occlusion location and investigational center. The study follows a sequential analysis (triangular model) with the first approach to test efficacy at 174 patients and subsequent analyses (if necessary) at 346, 518, and 690 subjects. Secondary end-points are infarct volume evaluated on CT at 24 h, dramatic early favorable response, defined as NIHSS of 0-2 or NIHSS improvement ≥8 points at 24 h and successful recanalization in the Solitaire arm according to the thrombolysis in cerebral infarction (TICI) classification defined as TICI 2b or 3. Safety variables are mortality at 90 days, symptomatic intracranial haemorrhage rates at 24 hours and procedure related complications.

Imaging negative stroke: diagnoses and outcomes in intravenous tissue plasminogen activator-treated patients

BACKGROUND

Intravenous (IV) Alteplase (tissue plasminogen activator [t-PA]) improves outcome in patients with acute ischemic stroke. Of those with full recovery, some may not have had ischemia. We analyzed the frequency and post-treatment outcomes of stroke code patients with no imaging evidence of stroke to establish the incidence of neuroimaging negative cerebral ischemia (NNCI) and stroke mimics treated with t-PA. In addition, we compared these patients with the group of stroke patients with imaging evidence of acute stroke to determine whether there was a difference in adverse events and functional outcomes.

METHODS

We included all adult stroke patients treated with IV t-PA within 3 hours of stroke onset from the University of California, San Diego, Specialized Programs of Translational Research in Acute Stroke database through January 2013. The imaging positive stroke (IPS) code group comprised patients with neuroimaging evidence of acute ischemic stroke, whereas the imaging negative stroke code (INS) group included those patients without neuroimaging evidence of acute cerebral ischemia. All final diagnoses were reviewed by an adjudicating body. We reviewed medical records and neuroimaging; compared discharge diagnosis, 90-day modified Rankin Scale (mRS) score, and incidence of intracranial hemorrhage; and adjusted for age, admission National Institutes of Health Stroke Scale (NIHSS), prestroke mRS, and diabetes in multivariable models.

RESULTS

We identified 106 patients, 74 IPS patients and 32 INS patients, who had similar baseline characteristics, except for baseline NIHSS (IPS 12.9 ± 8.2, INS 8.0 ± 5.6, P = .002) and incidence of cardiac arrhythmias (IPS 32.4%, INS 12.5%, P = .034). The diagnoses in the INS group were stroke (23, 72%)-representing NNCI, somatization (6, 19%), tumor (1, 3%), seizure (1, 3%), and migraine (1, 3%). All IPS patients were diagnosed with acute ischemic stroke. Adjusted for age, baseline NIHSS, prestroke mRS, and diabetes, the INS patients had significantly higher rates (odds ratio 3.04, P = .036) of good functional outcome (90-day mRS score 0-1). Intracerebral hemorrhage (ICH) was found in 24% of the IPS patients and was symptomatic in 6.8%. None of the INS patients had ICH.

CONCLUSIONS

Because most INS patients were found to have NNCI, which may represent either transient ischemic attack or aborted stroke, and there were no intracerebral hemorrhages in the INS group, our data support the safety of administering IV t-PA to all patients in whom acute ischemic stroke is clinically suspected. We have demonstrated that NNCI patients and stroke mimics are common, and future larger scale prospective studies are required to delineate the true frequencies of each and to evaluate differences in outcomes.

Huang-Lian-Jie-Du-Decotion induced protective autophagy against the injury of cerebral ischemia/reperfusion via MAPK-mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du-Decotion (HLJDD, Hwangryun-Hae-Dok-Decotion in Japan), an ancient antipyretic and detoxifying traditional Chinese medicine formula, was reported to have protective effect on ischemic stroke.

AIM OF THE RESEARCH

To investigate the therapeutic effect of HLJDD on ischemic stroke and explore its mode of action.

MATERIAL AND METHODS

A model of ischemic stroke in the rat was established after transient middle cerebral artery occlusion (MCAO) followed by reperfusion. Rats were assigned randomly to groups of control, sham, transient ischemia/reperfusion (I/R), and three treatment groups by HLJDD at 2.5, 5.0, 10.0mg/kg. The neurological deficit, the cerebral infarct size, morphology abnormality, biochemical parameters were examined, and the levels of relevant proteins were determined by immunoblotting analysis to evaluate the protective effects of HLJDD on ischemic stroke and explore the underlying mechanism.

RESULTS

Compared with I/R group, HLJDD significantly ameliorated neurological deficit and histopathology changes, decreased infarct area, and restored the levels of biochemical indicators including nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), glutathione disulfide (GSSG), total superoxide dismutase (T-SOD), Cu/Zn-SOD, Mn-SOD and glutathione peroxidase (GSH-PX). HLJDD also notably elevated the levels of microtubule-associated protein 1 light chain 3 (LC3), Beclin-1, and other autophagy related genes (Atgs), promoted the activation of extracellular signal-regulated kinases (ERK), protein kinase B (Akt), 3-phosphoinositide-dependent kinase (PDK1), and inhibited the activation of mammalian target of rapamycin (mTOR), c-Jun N-terminal protein kinases (JNK), p38, phosphatase and tensin homolog (PTEN).

CONCLUSION

HLJDD showed neuroprotective effects on ischemic stroke, at least in part to the induced protective autophagy via the regulation of mitogen-activated protein kinase (MAPK) signals. This Akt-independent protective autophagy is favorable in the treatment of stroke, avoiding unfavorable side-effects associated with the inactivation of Akt. The efficacy of HLJDD on ischemic stroke and its safety warranted by its long-term clinical use in traditional Chinese medicine favored further study to develop HLJDD as an effective therapeutic agent to treat ischemic stroke.

Molecular basis and thrombotic manifestations of antithrombin deficiency in 15 unrelated Chinese patients

INTRODUCTION

Antithrombin (AT) deficiency is associated with an increasing risk of thrombosis.

MATERIALS AND METHODS

15 unrelated patients with AT deficiency defined by thrombophilic assays were recruited and detailed clinical information about patients, focusing on the personal and family history of thromboembolism (TE), were recorded. Mutation analysis was performed by direct sequencing of an AT gene (SERPINC1) in the patients and their family members.

RESULTS

A total of 15 heterozygous causative mutations, each being identified in one family, were identified. Five mutations (33.3%) were reported here for the first time, including three null mutations (Ser36X, Lys70X and Try307X) and two missense mutations (Phe123Cys and Leu340Phe) probably impairing the structural integrity and stability of protein based on the AT structural analysis. Of the 15 patients, 33.3% (5/15) had additional risk factors and only one patient presented with additional genetic alteration causing an early onset of thrombosis. Fourteen patients (93.9%) suffered from multisite recurrent thrombotic episodes after a first episode of thrombosis. 93.3% of the patients experienced deep vein thrombosis (DVT) and 40.0% presented with mesenteric venous thrombosis (MVT). In addition, both venous and arterial thrombosis was present in two unrelated patients. 51.0% subjects with AT deficiency in the 15 unrelated pedigrees experienced TE events.

CONCLUSIONS

Prophylactic anticoagulation may be suggested in AT-deficient patients to avoid the recurrent and multisite thrombosis. The association of primary MVT and AT deficiency is highlighted.

Comparison of markers of coagulation activation and thrombin generation test in uncomplicated pregnancies

INTRODUCTION

Pregnancy is a well-established risk factor for venous thromboembolism, and is associated with a state of hypercoagulability or parameters of thrombin generation. Currently, there is a lack of consensual data on thrombin generation during pregnancy. This study aimed to find a sensitive and specific biological marker of coagulation activation and to identify parameters of thrombin generation.

PATIENTS AND METHODS

The population included 101 women with uncomplicated pregnancies. The objective of this study was to correlate thrombin generation test (measured at 5pM tissue factor, 4μM lipids and without thrombomodulin), with fibrinogen and markers of blood coagulation activation: D-dimer, prothrombin fragments 1+2 (F1+2), thrombin-antithrombin complexes (TAT) and fibrin monomer complexes (FMC) in these women. Internal quality control was performed in each set of experiments.

RESULTS

Fibrinogen, D-dimer, F1+2, and TAT concentrations increased significantly throughout pregnancy, and were correlated with term of pregnancy. In our study, thrombin generation seemed to increase early on, and then remained stable throughout normal pregnancy, in contrast with other markers of blood coagulation activation, excepting FMC. The latter are subject to large inter-individual variations, especially during second trimester. No correlation was demonstrated between thrombin generation parameters and other activation markers.

CONCLUSION

While markers of coagulation activation significantly increased during pregnancy, thrombin generation increased only early on and remains stable during pregnancy. Finding a sensitive and specific biological marker for vascular pregnancy complications, such as FMC and thrombin generation levels, requires further investigation.

Rosiglitazone attenuates hyperglycemia-enhanced hemorrhagic transformation after transient focal ischemia in rats

Hemorrhagic transformation (HT) has been claimed to represent the most feared complication of treatment with intravenous tissue plasminogen activator (t-PA) therapy. In this study, we tested the effect of rosiglitazone on HT in a rat focal cerebral ischemia model. Male Sprague-Dawley rats received an injection of 50% dextrose (6ml/kg intraperitoneally) and were subjected to middle cerebral artery occlusion (MCAO) 10 min later, with the regional cerebral blood flow monitored in vivo by laser-Doppler-flowmetry. Two groups were included: rosiglitazone treatment and vehicle group. In the treatment group, after 1.5h of ischemia, rosiglitazone (2mg/kg) was administered at the onset of reperfusion. Neurobehavioral scores, infarct volume, hemoglobin leakage, hemorrhage rate, the expression of collagen IV and glucose transporter 1 (GLUT1) were measured at 24h after ischemia. Rosiglitazone improved neurobehavioral deficits, reduced infarct volume and hemorrhage rate, and inhibited hemoglobin leakage, when compared with the vehicle group. In addition, it increased the expression of collagen IV and GLUT1 compared to the vehicle group. Our results suggest that rosiglitazone attenuated the hyperglycemia-induced HT after MCAO, possibly by preservation of GLUT1 expression.

Cerebroprotective effects of TAK-937, a novel cannabinoid receptor agonist, in permanent and thrombotic focal cerebral ischemia in rats: therapeutic time window, combination with t-PA and efficacy in aged rats

Some occluded arteries of acute ischemic stroke (AIS) patients are not recanalized, even if thrombolytic therapy is performed. Considering such clinical settings, we examined the potential cerebroprotective efficacy of TAK-937, a novel cannabinoid receptor agonist, in young adult and aged rats with a permanent middle cerebral artery occlusion (MCAO) model and conducted a combination study with TAK-937 and tissue type plasminogen activator (t-PA) in a rat thrombotic MCAO model. TAK-937 significantly reduced infarct volume when it was administered 3 and 5h after permanent MCAO in young adult rats. A thrombotic MCAO was induced by photo-irradiation of the middle cerebral artery with Rose Bengal administration and a permanent MCAO was produced by thermoelectric coagulation of occluded arteries. TAK-937 (10, 30 and 100μg/kg/h) was intravenously infused 1, 3, 5, or 8-24h after MCAO. t-PA (3 or 10mg/kg) was intravenously administered 1, 1.5 or 2h after MCAO. Infarct volume was determined using a 2,3,5-triphenyltetrazolium chloride staining method 24 or 48h after MCAO. The combined treatment of TAK-937 with t-PA significantly reduced the cerebral infarction compared with t-PA treatment alone in a rat thrombotic MCAO model. TAK-937 reduced infarct volume of aged rats as well, when it was administered 1h after permanent MCAO. These results suggest that TAK-937 exerts protective effects regardless of age and has a wide therapeutic time window in permanent occlusion. Furthermore, combined treatment of TAK-937 with t-PA would provide more therapeutic efficacy compared to t-PA treatment alone.

Coagulofibrinolytic changes in patients with disseminated intravascular coagulation associated with post-cardiac arrest syndrome--fibrinolytic shutdown and insufficient activation of fibrinolysis lead to organ dysfunction

INTRODUCTION

Post-cardiac arrest syndrome (PCAS) is often associated with disseminated intravascular coagulation (DIC), thus leading to the development of multiple organ dysfunction syndrome (MODS). The aim of this study was to examine the pathophysiological relationships between coagulation, fibrinolysis and fibrinolytic shutdown by evaluating the levels of coagulofibrinolytic markers, including soluble fibrin, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator-plasminogen activator inhibitor-1 complex (tPAIC), plasmin-alpha2 plasmin inhibitor complex (PPIC), neutrophil elastase and fibrin degradation product by neutrophil elastase (EXDP).

MATERIALS AND METHODS

Fifty-two resuscitated patients were divided into two groups: 22 DIC and 30 non-DIC patients.

RESULTS

The levels of soluble fibrin, PPIC, tPAIC, EXDP and neutrophil elastase in the DIC patients with PCAS were significantly higher than those observed in the non-DIC patients. The values of the tPAIC and JAAM DIC scores were found to be independent predictors of increased SOFA scores in the DIC patients. The MODS patients demonstrated significantly higher levels of soluble fibrin and tPAIC; however, the levels of TAFI and EXDP were identical between the patients with and without MODS. In addition, positive correlations were observed between the levels of tPAIC and EXDP in the patients with non-MODS; however, no correlations were observed between these markers in the MODS patients.

CONCLUSIONS

Thrombin activation and fibrinolytic shutdown play important roles in the development of organ dysfunction in PCAS patients. Neutrophil elastase-mediated fibrinolysis cannot overcome the fibrinolytic shutdown that occurs in DIC patients with PCAS, thus resulting in the development of MODS.

Adenosine diphosphate reduces infarct size and improves porcine heart function after myocardial infarct

Acute myocardial infarction continues to be a major cause of morbidity and mortality. Timely reperfusion can substantially improve outcomes and the administration of cardioprotective substances during reperfusion is therefore highly attractive. Adenosine diphosphate (ADP) and uridine-5-triphoshate (UTP) are both released during myocardial ischemia, influencing hemodynamics. Both mediate the release of tissue plasminogen activator (t-PA), which can reduce infarct size (IS). The objective of this study was to investigate whether exogenous ADP and UTP administration during reperfusion could reduce myocardial IS and whether this correlated to t-PA release or improvements in hemodynamic responses. Hemodynamic variables and t-PA were measured in 22 pigs before, during, and after 45 min of left anterior coronary artery occlusion. During reperfusion, the pigs were randomized to 240 min of intracoronary infusion of ADP, UTP, or control (no intervention). Ischemic area compared to the area at risk [IS/AAR] was measured. [IS/AAR] was 52 ± 11% in the control animals. ADP decreased [IS/AAR] by 19% (P < 0.05), while UTP increased [IS/AAR] by 15% (P < 0.05). Cardiac output (CO) increased from 3.4 to 3.5 L/min (P < 0.05) and mean arterial pressure (MAP) decreased from 87 to 73 mmHg in the ADP group (P < 0.05). t-PA concentration increased in the ADP and UTP group from 2.0 ng/mL to 2.5 and 2.4 ng/mL, respectively (P < 0.05) but remained unchanged in the control group. In conclusion, intracoronary ADP infusion during reperfusion reduces IS by ∼20% independently from systemic release of t-PA. ADP-induced reduction in both preload and afterload could account for the beneficial myocardial effect.

Pathophysiology of thoracic aortic aneurysm (TAA): is it not one uniform aorta? Role of embryologic origin

Thoracic aortic aneurysm (TAA) is a clinically silent and potentially fatal disease whose pathophysiology is poorly understood. Application of data derived from animal models and human tissue analysis of abdominal aortic aneurysms may prove misleading given current evidence of structural and biochemical aortic heterogeneity above and below the diaphragm. Genetic predisposition is more common in TAA and includes multi-faceted syndromes such as Marfan, Loeys-Dietz, and type IV Ehlers-Danlos as well as autosomal-dominant familial patterns of inheritance. Investigation into the consequences of these known mutations has provided insight into the cell signaling cascades leading to degenerative remodeling of the aortic medial extracellular matrix (ECM) with TGF-β playing a major role. Targeted research into modifying the upstream regulation or downstream effects of the TGF-β1 pathway may provide opportunities for intervention to attenuate TAA progression.

Beta-amyloidolysis and glutathione in Alzheimer's disease

In this review, we hypothesized the importance of the interaction between the brain glutathione (GSH) system, the proteolytic tissue plasminogen activator (t-PA)/plasminogen/ plasmin system, regulated by plasminogen activator inhibitor (PAI-1), and neuroserpin in the pathogenesis of Alzheimer’s disease. The histopathological characteristic hallmark that gives personality to the diagnosis of Alzheimer’s disease is the accumulation of neurofibroid tangles located intracellularly in the brain, such as the protein tau and extracellular senile plaques made primarily of amyloidal substance. These formations of complex etiology are intimately related to GSH, brain protective antioxidants, and the proteolytic system, in which t-PA plays a key role. There is scientific evidence that suggests a relationship between aging, a number of neurodegenerative disorders, and the excessive production of reactive oxygen species and accompanying decreased brain proteolysis. The plasminogen system in the brain is an essential proteolytic mechanism that effectively degrades amyloid peptides (“beta-amyloidolysis”) through action of the plasmin, and this physiologic process may be considered to be a means of prevention of neurodegenerative disorders. In parallel to the decrease in GSH levels seen in aging, there is also a decrease in plasmin brain activity and a progressive decrease of t-PA activity, caused by a decrease in the expression of the t-PA together with an increase of the PAI-1 levels, which rise to an increment in the production of amyloid peptides and a lesser clearance of them. Better knowledge of the GSH mechanism and cerebral proteolysis will allow us to hypothesize about therapeutic practices.