Swarming magnetic nanorobots bio-interfaced by heparinoid-polymer brushes for in vivo safe synergistic thrombolysis

Biocompatible swarming magnetic nanorobots that work in blood vessels for safe and efficient targeted thrombolytic therapy in vivo are demonstrated. This is achieved by using magnetic beads elaborately grafted with heparinoid-polymer brushes (HPBs) upon the application of an alternating magnetic field B(t). Because of the dense surface charges bestowed by HPBs, the swarming nanorobots demonstrate reversible agglomeration-free reconfigurations, low hemolysis, anti-bioadhesion, and self-anticoagulation in high-ionic-strength blood environments. They are confirmed in vitro and in vivo to perform synergistic thrombolysis efficiently by "motile-targeting" drug delivery and mechanical destruction. Moreover, upon the completion of thrombolysis and removal of B(t), the nanorobots disassemble into dispersed particles in blood, allowing them to safely participate in circulation and be phagocytized by immune cells without apparent organ damage or inflammatory lesion. This work provides a rational multifaceted HPB biointerfacing design strategy for biomedical nanorobots and a general motile platform to deliver drugs for targeted therapies.

Association of Heparin-Like Effect, Factor VII/XIII Deficiency and Fibrinolysis with Rebleeding Risk in Cirrhosis with Acute Variceal Bleeding

BACKGROUND

Hyperfibrinolysis and coagulation dysfunction may occur in cirrhotic patients with acute variceal bleed (AVB) despite successful endotherapy.

AIMS

To prospectively study the association of endogenous heparinoids and coagulation dysfunction with variceal rebleeding and outcome in cirrhosis.

METHODS

Consecutive patients were assessed with conventional coagulation tests, SONOCLOT™ [(global(gb) and heparinase(h) treated] and factors VII, VIII, XIII, X, tissue plasminogen activator, and plasminogen activator inhibitor ELISA assays in a university hospital. Heparin-like-effect (HLE) was defined as ≥ 20% difference in paired gb/h-SONOCLOT™ traces for activated clotting time (ACT).

RESULTS

Of 143 patients screened, 90 (46.4 ± 11.7 years, males 82.2%, ethanol-related 58.8%) were recruited, who bled from esophageal varices (81,90.0%), gastric varices (6,6.6%), or esophageal varices with portal hypertensive gastropathy (3,3.3%). Twenty (21.7%) had early rebleeding, mainly post-variceal ligation ulcer related (70%). Patients who rebled had low Factor XIII [1.6 (1.2-2.1) vs 2.4 ng/ml (2.0-2.8) P = 0.035] and Factor VII (94.1 ± 46.9 vs. 124.0 ± 50.4, P = 0.023). On receiver operating curve analysis, the gbACT > 252 s (sensitivity 86.8%, specificity 76.9%, P < 0.001), hACT > 215 s (sensitivity 71.1%, specificity 70.3%, P < 0.001), and HLE > 50% (sensitivity 69.5%, specificity 70.3%, P = 0.006) predicted rebleeding. Baseline Factor VIII (HR 1.26; 95% CI 1.17-1.34, P < 0.001), low factor VII (HR 0.89; 95% CI 0.76-0.98, P = 0.035), and lysis (HR 1.25, 95% CI 1.17-1.33, P < 0.001) predicted mortality. Endogenous heparinoids at baseline predicted sepsis (HR 1.8; 95% CI 1.4-6.5; P = 0.022), rebleeding events (HR 1.2; 95% CI 1.1-6.3; P = 0.030), and mortality (HR 1.1; 95% CI 1.0-4.6; P = 0.030).

CONCLUSIONS

Hyperfibrinolysis, Factor VII/XIII deficiency, and HLE are associated with rebleeding after AVB. Trial Registration NCT04111120 available from https://clinicaltrials.gov/ct2/show/NCT04111120 .

Thrombotic Events and Anticoagulation-Related Bleeding Complications in Critically Ill Patients with Coronavirus Disease 2019

Background: Thrombosis (T) is common in coronavirus disease 2019 (COVID-19) patients, and d-dimer concentrations correlate with outcomes. Controversy exists with regards to anticoagulation (AC) for patients. We implemented a full-heparinization AC protocol from the onset of the pandemic and hypothesized that a safety signal would be undetectable. Patients and Methods: Prospective evaluation of 111 patients with COVID-19 critical illness hospitalized from March to June 2020. All patients received therapeutic heparinoid-based AC from admission. Incidences of T, bleeding (B), or both (BT) were noted. The primary outcome was mortality. Kruskal-Wallis test and logistic regression were performed. Results are expressed as n (%), median (interquartile range) and odds ratios with 95% confidence intervals. Alpha was set at 0.05. Results: Thirty-two patients (28%) had T, 23 (20%) had B, and 14 (12%) had BT; 42 (40%) patients were unaffected. Two logistic regression models (outcome = mortality) evaluated BT as T, or BT as B. For BT as T, neither T, B, nor male gender predicted mortality; similarly, for BT as B, neither T, B, nor male gender predicted mortality. Factors associated with higher odds of death included higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.00-1.13; p = 0.0045), higher d-dimer concentration (OR, 1.00; 95% CI, 1.00-1.01; p = 0.043), and higher activated partial thromboplastin time (aPTT; OR, 1.09; 95% CI, 1.02-1.16; p = 0.010). Conclusions: Neither T nor B predicted mortality in this prospective cohort of anticoagulated patients with COVID-19 critical illness. These data support continued full-dose heparinoid prophylaxis.

[Effect of admixture of commercially available corticosteroid ointments and/or creams on vasoconstrictor activity]

A commonly used admixture of commercially available ointments and/or creams was selected from the prescribed sheets in our hospital, and questionnaire to dermatologists. To assess the relationship between permeability of corticosteroid through murine skin and clinical effects in human, we attempted to investigate the vasoconstrictor activity of these admixtures of topical corticosteroid by double-blind controlled study. Test samples were occluded at random on the back of 20 healthy volunteers for 4 hours. The vasoconstrictor activity of corticosteroid creams (Lidomex) alone was significantly large as compared with that of ointments alone. The vasoconstrictor activity of corticosteroid in the admixture of Lidomex ointment and urea ointments or heparinoid ointment was 1.5-2 fold significantly larger than that from ointments alone. The extent of the stability of the emulsion after mixing was related to the vasoconstrictor activity. These experiments demonstrated a close relationship between the vasoconstrictor activity of human skin and permeability of hairless mice skin. These results suggested that the vasoconstrictor activity of topical corticosteroids mixed with commercially available ointments and/or creams depends upon their physicochemical characteristics.

Anticoagulation in patients with heparin-induced thrombocytopenia type II

Heparin-induced thrombocytopenia (HIT) together with simultaneously occurring thromboembolism is a serious complication of heparin treatment. At present an immunologic cause of this side effect of heparin is equivocally accepted. However, further anticoagulation of these patients is still debated. The present article summarizes the treatment of 20 patients with such complications. Two of these patients did not develop thrombocytopenia but presented cutaneous allergy or necrosis. All patients were treated either with intravenous heparinoid (Orgaran) or with low-molecular-weight heparin without/with simultaneous intravenous high-dose immunoglobulins or with intravenous r-hirudin. Based on these experiences the treatment of choice depends at present on the availability of the anticoagulants and on the local experience with the different anticoagulants. In the future r-hirudins and other nonheparin thrombin inhibitors may become the drugs of choice in this indication. Surgical intervention has to be considered additionally.

[The evaluation of the oximetric and Doppler sonographic parameters in patients with chronic venous insufficiency. A controlled double-blind clinical study versus placebo]

Twenty four patients suffering from chronic venous insufficiency of the lower limbs were treated with sulfo-mucopolysaccharides (SMPS) or placebo in a double-blind controlled study. At recruitment, and again at 60 and 120 days of ongoing treatment, each patient was tested for transcutaneous partial oxygen tension and for pressure in the posterior tibial vein and saphena by Doppler sonography. Findings were assessed in each case separately for the affected limb versus the unaffected, or for the more severely affected versus the contralateral limb in patients affected bilaterally. Patients treated with the test product, but not those treated with placebo, showed definite reduction of venous pressure in the posterior tibial vein and internal saphena of the affected or more severely affected limb at 60 days of treatment: namely -35% from basal for the posterior tibial vein and -28% for the internal saphena. Again on the affected or more severely affected side, patients treated with SMPS showed improved transcutaneous oxygen tension amounting to +13.8% from basal at 60 days, as opposed to worsening condition in the placebo group.

Grafting of a synthetic heparinoid polyelectrolyte onto silicone rubber

Using a [3H]-labelled polyelectrolyte as a tracer, the 60Co grafting of a synthetic heparinoid polyelectrolyte onto silicone rubber was studied. The polyelectrolyte was labelled by the coupling of a radioactive amine to carboxylate groups of the polyelectrolyte. The amount of grafted polyelectrolyte was found to be dependent on the radiation dose.