Heparin as a therapy for atherosclerosis: preliminary observations on the intrapulmonary administration of low-dose heparin in the morning versus evening gauged by its effect on blood variables

Systematic review: differences in complete blood count component rhythms

Study Objectives

The complete blood count (CBC) is one of the most commonly ordered blood tests with a large range of reference values that does not consider time of day for interpretation. Our objective was to systematically review this topic to report on peak and trough timing of CBC values.

Methods

A systematic search was performed for studies evaluating any component of the CBC with at least three collections over 24 hours. The studies were screened based on the predetermined eligibility criteria. Meta-analysis of aggregated data was analyzed with polynomial functions and forest plots.

Results

In total, 164 full-text articles were screened and 32 included in the final analysis with 548 total patients considering either leukocytes (n = 13), erythrocytes (n = 7), hemoglobin (n = 5), hematocrit (n = 5), platelets (n = 12), neutrophils (n = 11), lymphocytes (n = 13), monocytes (n = 8), eosinophils (n = 15), or basophils (n = 9). CBC components were analyzed by polynomial and forest plot analysis. Lymphocytes fitted best to a third-degree polynomial function (p = .010) with peak at 2264.87 cells/µL at 23:54 (CI: 1783.44 to 2746.31) with a trough of 1598.91 cells/µL at 10:47 (CI: 1230.12 to 1967.71). Lymphocytes and eosinophils peaked overnight, while erythrocytes, hemoglobin, and hematocrit peaked in the morning, and platelets, neutrophils, monocytes, and basophils peaked in late afternoon. Limitations include small sample size and significant study heterogeneity.

Conclusion

We identified a limited scope of studies characterizing CBC component rhythms. However, we still noted significant differences, particularly with lymphocytes. Future work should evaluate larger datasets to inform time-dependent interpretation of the CBC as we move toward precision medicine.

Inhalational use of antithrombotics in humans: Review of the literature

INTRODUCTION

Off label use of anticoagulants is common. The association between fibrin deposition in the lungs and primary lung disease, injury or prematurity affords a strong theoretical basis for the potential benefit of antithrombotic therapies administered directly to the lung tissue. This review offers a critical appraisal of current evidence related to the inhalational administration of antithrombotic therapy in humans.

MATERIALS AND METHODS

An interrogation of 2 databases across a 13 year period of time was undertaken using key words selected a priori. Identified publications were categorized according to the following themes: 1. Inhaled antithrombotic therapy in healthy subjects 2. Inhaled antithrombotic therapy for vascular thromboprophylaxis 3. Inhaled antithrombotic therapy in smoke inhalation and lung injury 4. Inhaled antithrombotic therapy in asthma or allergy 5. Inhaled antithrombotic therapy for plastic bronchitis post-Fontan surgery 6. Inhaled antithrombotic therapy for other indications.

RESULTS

33 articles were identified consistent with the inclusion criteria developed for this review. Unfractionated heparin, LMWH, activated protein C and thrombolytic agents have been administered via the respiratory track, with asthma and smoke inhalation/lung injury being the most frequently investigated clinical scenarios described. All studies reported had significant methodological limitations.

CONCLUSIONS

The safety and clinical utility of inhaled antithrombotic therapies have not been adequately investigated to support the generation of any firm evidence. This review highlights where inhaled antithrombotic therapies have shown promise and importantly, the further research required to confirm mechanism of action and a definitive risk: benefit profile.

Prevention of calcification in glutaraldehyde-treated porcine aortic and pulmonary valves

BACKGROUND

The problem of calcification in porcine aortic (AVs) and pulmonary (PVs) valves and its relationship to glutaraldehyde (GA) is of current interest. We proposed an anticalcification treatment to develop noncalcifying porcine AVs and PVs.

METHODS

Porcine AVs and PVs were cross-linked in GA. Partially degraded heparin was coupled to the GA-treated AVs and PVs through intermediate surface-bound substrate containing amino groups. Control AVs and PVs were cross-linked in 0.625% GA but had no heparin coupling. All specimens were implanted subdermally in 3-week-old rats for 5 months for calcification studies.

RESULTS

Control AVs (Ca, 233.69 +/- 42.61 mg/g) and PVs (Ca, 181.48 +/- 4.06 mg/g) were severely calcified. Coupling of partially degraded heparin revealed complete prevention of calcification in GA-treated AVs (Ca, 0.73 +/- 0.27) and PVs (Ca, 1.125 +/- 0.22 mg/g) implanted subcutaneously in weanling rats for 5 months.

CONCLUSIONS

The proposed anticalcification treatment is effective in preventing calcification of GA-treated AVs and PVs implanted subcutaneously in weanling rats for 5 months.

Heparin in calcification prevention of porcine pericardial bioprostheses

Calcific degeneration is the main cause of failure of glutaraldehyde-treated xenograft heart valve substitutes implanted in humans. Coupling of heparin through an intermediate surface-bound substrate containing amino groups showed complete prevention of calcification of glutaraldehyde-treated porcine pericardium implanted subdermally in weanling rats for 5 months (heparin bonded pericardium: calcium, 0.625 +/- 0.24 mg g(-1); glutaraldehyde-only-treated pericardium: calcium, 228.32 +/- 37.39 mg g(-1); P < 0.0001). Conceivably, inactivation of unpaired aldehyde moieties present in bioprostheses after exposure to glutaraldehyde by amino compounds followed by blocking the potential binding sites of the graft with a surface modifying agent like heparin would be the key steps in the prevention of calcification and degeneration of glutaraldehyde-treated biological tissue grafts.