Assessment of histological characteristics, imaging markers, and rt-PA susceptibility of ex vivo venous thrombi

Cutting-edge advances in nano/biomedicine: A review on transforming thrombolytic therapy

Thrombotic blockages within blood vessels give rise to critical cardiovascular disorders, including ischemic stroke, venous thromboembolism, and myocardial infarction. The current approach to the therapy of thrombolysis involves administering Plasminogen Activators (PA), but it is hindered by fast drug elimination, narrow treatment window, and the potential for bleeding complications. Leveraging nanomedicine to encapsulate and deliver PA offers a solution by improving the efficacy of therapy, safeguarding the medicine from proteinase biodegradation, and reducing unwanted effects in in vivo trials. In this review, we delve into the underlying venous as well as arterial thrombus pathophysiology and provide an overview of clinically approved PA used to address acute thrombotic conditions. We explore the existing challenges and potential directions within recent pivotal research on a variety of targeted nanocarriers, such as lipid, polymeric, inorganic, and biological carriers, designed for precise delivery of PA to specific sites. We also discuss the promising role of microbubbles and ultrasound-assisted Sono thrombolysis, which have exhibited enhanced thrombolysis in clinical studies. Furthermore, our review delves into approaches for the strategic development of nano-based carriers tailored for targeting thrombolytic action and efficient encapsulation of PA, considering the intricate interaction in biology systems as well as nanomaterials. In conclusion, the field of nanomedicine offers a valuable method for the exact and effective therapy of severe thrombus conditions, presenting a pathway toward improved patient outcomes and reduced complications.

Evaluating the stage of deep vein thrombosis: the diagnostic accuracy of shear wave elastography and super-microvascular imaging

Background

Assessing the age of deep vein thrombosis (DVT) is crucial for guiding treatment approaches. Two-dimensional shear-wave elastography (2D-SWE) and super-microvascular imaging (SMI), as emerging techniques for tissue elasticity assessment and intrathrombus microvascular analysis, are pivotal for accurate thrombus age determination. This research endeavors to classify DVT into acute, subacute, and chronic ages utilizing these imaging methods.

Methods

The study is a prospective, single-center, inpatient investigation that utilized convenience sampling for participant recruitment. Patients with a symptom duration of <6 months who were found to have lower-extremity DVT on ultrasound (US) between January 2021 and March 2022 after craniocerebral trauma (CT) or bone injury (BI) operations were included in this study. Participants were divided into three groups based on the duration of DVT, measured from the first diagnosis of thrombosis by US to the follow-up with 2D-SWE and SMI: acute (≤14 days), subacute (15-30 days), and chronic (31 days to 6 months) All patients underwent 2D-SWE and SMI using an Aplio i700 Ultrasound System equipped with a PLT-1005BT line array probe. Diagnostic performance was assessed using the area under the receiver operating characteristic (ROC) curve.

Results

The maximum value of the elastic modulus for DVT (DVT_Emax), the mean value of the elastic modulus for DVT (DVT_Emean), and SMI's flow distribution scoring pattern for DVT (SMI_scoring) emerged as significant predictors for acute and chronic, with high area under the ROC curve (AUC) of acute [AUC (95% confidential interval): 0.95 (0.89-0.97), 0.96 (0.91-0.98), 0.93 (0.88-0.97) in 39 patients] and chronic [AUC (95% confidential interval): 0.88 (0.81-0.93), 0.94 (0.88-0.97), 0.91 (0.84-0.95) in 51 patients], respectively. However, these indices had lower efficacy for subacute prediction [AUC (95% confidential interval): 0.51 (0.42-0.60), 0.54 (0.46-0.63), 0.53 (0.44-0.62), in 47 patients]. Combining DVT_Emean with SMI_scoring improved performance in predicting subacute: 0.90 (0.83-0.94) than related features alone.

Conclusions

Both 2D-SWE and SMI can be used to assess acute and chronic DVT in patients with CT and BI after surgeries. This combination is a promising adjunctive technique for identifying the subacute phase of DVT in these patients.

Effect of Ultrasound on Thrombus debris during Sonothrombolysis in a Microfluidic device

Microbubble-mediated sonothrombolysis has been proven to be a non-invasive and efficient method for thrombolysis. Nevertheless, there is a potential risk that the thrombus debris generated during the dissolution of the original thrombus are too large and can lead to hazardous emboli. Using a sonothrombolysis microfluidic platform, we investigated the effects of ultrasound power, thrombolytic agent and microbubble concentration on the size of thrombus debris with the example of microbubble-mediated sonothrombolysis of arterial thrombus. Additionally, we studied the effects of ultrasound power on the size and shape of thrombus debris produced by acute and chronic arterial sonothrombolysis. In acute arterial sonothrombolysis, ultrasound power has significant effect on the size of thrombus debris and steadily increases with the increase of ultrasound power. Conversely, in chronic arterial sonothrombolysis, the size of thrombus debris is minimally affected by ultrasound power. Using the sonothrombolysis microfluidic platform, the relationship between ultrasound power and the safety of sonothrombolysis has been illustrated, and the sonothrombolysis microfluidic platform is demonstrated to be a promising tool for further studies on the process of sonothrombolysis.

Effect of rt-PA on Shear Wave Mechanical Assessment and Quantitative Ultrasound Properties of Blood Clot Kinetics In Vitro

OBJECTIVE

The consequences associated with blood clots are numerous and are responsible for many deaths worldwide. The assessment of treatment efficacy is necessary for patient follow-up and to detect treatment-resistant patients. The aim of this study was to characterize the effect of treatment on blood clots in vitro using quantitative ultrasound parameters.

METHODS

Blood from 10 pigs was collected to form three clots per pig in gelatin phantoms. Clots were subjected to 1) no treatment, 2) rt-PA (recombinant tissue plasminogen activator) treatment after 20 minutes of clotting, and 3) rt-PA treatment after 60 minutes of clotting. Clots were weighted before and after the experiment to assess the treatment effect by the mass loss. The clot kinetics was studied over 100 minutes using elastography (Young's modulus, shear wave dispersion, and shear wave attenuation). Homodyne K-distribution (HKD) parameters derived from speckle statistics were also studied during clot formation and dissolving (diffuse-to-total signal power ratio and intensity parameters).

RESULTS

Treated clots loosed significantly more mass than non-treated ones (P < .005). A significant increase in Young's modulus was observed over time (P < .001), and significant reductions were seen for treated clots at 20 or 60 minutes compared with untreated ones (P < .001). The shear wave dispersion differed for treated clots at 60 minutes versus no treatments (P < .001). The shear wave attenuation decreased over time (P < .001), and was different for clots treated at 20 minutes versus no treatments (P < .031). The HKD intensity parameter varied over time (P < .032), and was lower for clots treated at 20 and 60 minutes than those untreated (P < .001 and P < .02).

CONCLUSION

The effect of rt-PA treatment could be confirmed by a decrease in Young's modulus and HKD intensity parameter. The shear wave dispersion and shear wave attenuation were sensitive to late and early treatments, respectively. The Young's modulus, shear wave attenuation, and HKD intensity parameter varied over time despite treatment.

Resonance, Velocity, Dispersion, and Attenuation of Ultrasound-Induced Shear Wave Propagation in Blood Clot In Vitro Models

OBJECTIVE

Improve the characterization of mechanical properties of blood clots. Parameters derived from shear wave (SW) velocity and SW amplitude spectra were determined for gel phantoms and in vitro blood clots.

METHODS

Homogeneous phantoms and phantoms with gel or blood clot inclusions of different diameters and mechanical properties were analyzed. SW amplitude spectra were used to observe resonant peaks. Parameters derived from those resonant peaks were related to mimicked blood clot properties. Three regions of interest were tested to analyze where resonances occurred the most. For blood experiments, 20 samples from different pigs were analyzed over time during a 110-minute coagulation period using the Young modulus, SW frequency dispersion, and SW attenuation.

RESULTS

The mechanical resonance was manifested by an increase in the number of SW spectral peaks as the inclusion diameter was reduced (P < .001). In blood clot inclusions, the Young modulus increased over time during coagulation (P < .001). Descriptive spectral parameters (frequency peak, bandwidth, and distance between resonant peaks) were linearly correlated with clot elasticity values (P < .001) with R2  = .77 for the frequency peak, .60 for the bandwidth, and .48 for the distance between peaks. The SW dispersion and SW attenuation reflecting the viscous behavior of blood clots decreased over time (P < .001), mainly in the early stage of coagulation (first minutes).

CONCLUSION

The confined soft inclusion configuration favored SW mechanical resonances potentially challenging the computation of spectral-based parameters, such as the SW attenuation. The impact of resonances can be reduced by properly selecting the region of interest for data analysis.

Study on the Therapeutic Value of Shexiang Tongxin Dropping Pills in Patients with Stable Angina Pectoris of Coronary Heart Disease Complicated with Cognitive Impairment

BACKGROUND

There is a pressing need to identify pharmaceuticals that are both safe and efficacious, with lower toxicity, for the treatment of stable angina pectoris in individuals suffering from coronary heart disease. The aim of this paper is to explore the therapeutic value of Shexiang Tongxin Dropping Pills in patients with stable angina pectoris of coronary heart disease complicated with cognitive impairment.

METHODS

200 patients with stable angina pectoris combined with cognitive dysfunction and coronary heart disease admitted to our hospital from January 2022 to June 2023 were retrospectively selected as the study objects. According to the treatment method, the subjects were divided into a control group and a study group, with 100 cases in each group. The control group received conventional oral Western medicine, and the study group underwent treatment with Shexiang Tongxin Dropping Pills in addition to traditional Western medicine. The course of treatment was eight weeks. The enhancement in angina pectoris, cognitive function level, self-care ability, and clinical efficacy of both groups were assessed by comparing the conditions before and after the treatment.

RESULTS

After treatment, the frequency and duration of angina pectoris attacks in both groups were significantly lower than before, and the study group was lower than the control group (p < 0.05). The Montreal Cognitive Assessment (MoCA) score of both groups was higher than before, and the score of the study group was significantly higher than that of the control group (p < 0.05). Neuropsychiatric Inventory (NPI) scores in both groups were significantly lower than before, and the scores of the study group were significantly lower than those of the control group (p < 0.05). Traditional Chinese Medicine (TCM) syndrome scores in both groups were significantly lower than before, and the scores of the study group were significantly lower than those of the control group (p < 0.05). After treatment, the total effective rate of the control group and the study group was 81.00% and 93.00%, respectively, and the total clinical effective rate of the study group was significantly higher than that of the control group (p < 0.05).

CONCLUSION

Shexiang Tongxin Dropping Pills can effectively reduce the incidence of angina pectoris in patients with stable angina pectoris complicated with coronary heart disease and cognitive dysfunction. It can also regulate the patient's neurological function, improve their cognitive level, and significantly improve clinical efficacy.

Regulatory T cells in skin regeneration and wound healing

As the body's integumentary system, the skin is vulnerable to injuries. The subsequent wound healing processes aim to restore dermal and epidermal integrity and functionality. To this end, multiple tissue-resident cells and recruited immune cells cooperate to efficiently repair the injured tissue. Such temporally- and spatially-coordinated interplay necessitates tight regulation to prevent collateral damage such as overshooting immune responses and excessive inflammation. In this context, regulatory T cells (Tregs) hold a key role in balancing immune homeostasis and mediating cutaneous wound healing. A comprehensive understanding of Tregs' multifaceted field of activity may help decipher wound pathologies and, ultimately, establish new treatment modalities. Herein, we review the role of Tregs in orchestrating the regeneration of skin adnexa and catalyzing healthy wound repair. Further, we discuss how Tregs operate during fibrosis, keloidosis, and scarring.

In silico assessment of histotripsy-induced changes in catheter-directed thrombolytic delivery

Introduction: For venous thrombosis patients, catheter-directed thrombolytic therapy is the standard-of-care to recanalize the occluded vessel. Limitations with thrombolytic drugs make the development of adjuvant treatments an active area of research. One potential adjuvant is histotripsy, a focused ultrasound therapy that lyses red blood cells within thrombus via the spontaneous generation of bubbles. Histotripsy has also been shown to improve the efficacy of thrombolytic drugs, though the precise mechanism of enhancement has not been elucidated. In this study, in silico calculations were performed to determine the contribution of histotripsy-induced changes in thrombus diffusivity to alter catheter-directed therapy. Methods: An established and validated Monte Carlo calculation was used to predict the extent of histotripsy bubble activity. The distribution of thrombolytic drug was computed with a finite-difference time domain (FDTD) solution of the perfusion-diffusion equation. The FDTD calculation included changes in thrombus diffusivity based on outcomes of the Monte Carlo calculation. Fibrin degradation was determined using the known reaction rate of thrombolytic drug. Results: In the absence of histotripsy, thrombolytic delivery was restricted in close proximity to the catheter. Thrombolytic perfused throughout the focal region for calculations that included the effects of histotripsy, resulting in an increased degree of fibrinolysis. Discussion: These results were consistent with the outcomes of in vitro studies, suggesting histotripsy-induced changes in the thrombus diffusivity are a primary mechanism for enhancement of thrombolytic drugs.

Catheter-Directed Interventions for the Treatment of Lower Extremity Deep Vein Thrombosis

Lower extremity deep vein thrombosis (DVT) leads to significant morbidity including pain, swelling, and difficulty walking in the affected limb. If left untreated, DVT increases the risk of pulmonary embolism (PE), recurrent venous thromboembolism (VTE), and post thrombotic syndrome (PTS). The objective of this review was to identify catheter-directed interventions and their success rates for the treatment of lower extremity DVT. A comprehensive search of current and emerging catheter-directed interventions for lower extremity DVT treatment was conducted in PubMed and Google Scholar. Clinical trials, retrospective and prospective observational studies, and case reports were identified to classify percutaneous mechanical thrombectomy (PMT), catheter-directed thrombolysis (CDT), and pharmacomechanical CDT (PCDT) devices based on their mechanism of action and indication of use. Catheter-directed interventions such as PMT, CDT, and PCDT offer an alternative therapeutic strategy for DVT management, particularly in patients with limb-threatening conditions and absolute contraindications to anticoagulants. Currently, there are limited guidelines for the use of mechanical and pharmacomechanical devices because of the lack of clinical evidence available for their use in treatment. Future studies are required to determine the short and long-term effects of using catheter-directed interventions as well as their effectiveness in treating acute versus subacute and chronic DVT.

Histology of Cerebral Clots in Cryptogenic Stroke Varies According to the Presence of a Patent Foramen Ovale

Although a pathophysiological impact remains difficult to prove in individual patient care, a patent foramen ovale (PFO) is currently considered of high relevance for secondary prophylaxis in selected patients with cryptogenic ischemic stroke. By quantification of histological clot composition, we aimed to enhance pathophysiological understanding of PFO attributable ischemic strokes. Retrospectively, we evaluated all cerebral clots retrieved by mechanical thrombectomy for acute ischemic stroke treatment between 2011 and 2021 at our comprehensive stroke care center. Inclusion criteria applied were cryptogenic stroke, age (≤60 years), and PFO status according to transesophageal echocardiography, resulting in a study population of 58 patients. Relative clot composition was calculated using orbit image analysis to define the ratio of main histologic components (fibrin/platelets (F/P), red blood cell count (RBC), leukocytes). Cryptogenic stroke patients with PFO (PFO+, n = 20) displayed a significantly higher percentage of RBC (0.57 ± 0.17; p = 0.002) and lower percentage of F/P (0.38 ± 0.15; p = 0.003) compared to patients without PFO (PFO–, n = 38) (RBC: 0.41 ± 0.21; F/P: 0.52 ± 0.20). In conclusion, histologic clot composition in cryptogenic stroke varies depending on the presence of a PFO. Our findings histologically support the concept that a PFO may be of pathophysiological relevance in cryptogenic ischemic stroke.