Altered elastase-alpha1-antitrypsin balance in the blood of patients with chronic venous disease

The role of alpha-1-antitrypsin in the etiopathogenesis of chronic venous disease: A prospective clinical trial

OBJECTIVE

The study aimed to examine whether alpha-1-antitrypsin (AAT), an inhibitor of leukocyte esterase(LE), which damages the venous vessel wall, has a protective effect against chronic venous disease(CVD), and to examine the relationship between AAT levels and disease severity.

METHODS

Patients admitted with varicose vein disease and having reflux flow lasting longer than 0.5 s as determined by Doppler ultrasound were included. The informed consents were taken, and blood samples were obtained for complete blood count, C-reactive protein (CRP) level, and AAT level following anamnesis and physical examination. Clinical Etiologic Anatomic Pathologic (CEAP) classification was used to assess disease severity, and patients were divided into CEAP 1-5 groups accordingly.

RESULTS

A total of 87 patients were included in the study. There was no statistically significant difference between the groups in body weight, red blood cell counts, platelet counts, or neutrophil counts (p = 0.117, p = 0.932, p = 0.177, and p = 0.177, respectively).CRP and AAT levels were higher in patients with a CEAP clinical score of 5 compared to the other groups (p = 0.018, and p = 0.020, respectively). AAT levels were similar in the CEAP 1-3 group and decreased in the CEAP-4 group but increased again in the CEAP-5 group. The AAT level was 1.62 ± 0.3 g/L in the CEAP-1 group, 1.61 ± 0.21 g/L in the CEAP-2 group, 1.61 ± 0.27 g/L in the CEAP-3 group, 1.48 ± 0.28 g/L in the CEAP-4 group, and 1.94 ± 0.39 g/L in the CEAP-5 group. CRP levels and platelet counts were observed to affect AAT levels (p = 0.10, p = 0.017, respectively).

CONCLUSION

We believe that our hypothesis that low AAT levels play a role in the etiopathogenesis of CVD has been partially validated, at least in the CEAP-4 group. However, we believe that increased AAT levels in the CEAP-5 group may be a reactive increase in increased LE levels due to higher CRP levels of this group.

Plasma levels of leucocyte elastase-generated cross linked fibrin degradation products (E-XDP) are elevated in chronic venous disease

Patients with chronic venous disease (CVD) have elevated levels of leucocyte elastase (LE) released from the activation of leucocytes. In acute deep venous thrombosis (DVT), LE can degrade fibrin from the thrombus resulting in cross-linked fibrin degradation products (E-XDP) being released into the bloodstream. In patients with CVD the levels and significance of circulating E-XDP are unknown. We aimed to investigate the association between plasma E-XDP concentration and severity of CVD. Levels of E-XDP were quantified with a specific enzyme-linked immunosorbent assay (ELISA) in plasma from 142 consecutively recruited CVD patients (mean age 64 years, (range 23–89), 81 were females and 61 males). Patients were also divided into three groups based on CVD severity using the C-class of the Clinical-Etiological-Anatomical-Pathophysiological (CEAP) classification, with C 0–1 class as the reference group, C 2–3 as the second group and C 4–6 as the third group with the most severely affected patients. We found significantly elevated levels of E-XDP in patients with C 4–6 compared with patients with C 0–1 (p = 0.007) and increased with increasing disease severity across the groups (p = 0.02). Significant independent association was observed between levels of E-XDP and the classes C 4–6 after adjustment for age and sex (p < 0.05), but the association was no longer significant after further adjustment for use of statins, use of anticoagulants and history of DVT (p = 0.247). This exploratory study shows that E-XDP levels are elevated in patients with CVD, encouraging further studies on the role of E-XDP in CVD.

Protease activity as a prognostic factor for wound healing in venous leg ulcers

BACKGROUND

Venous leg ulcers (VLUs) are a common type of complex wound that have a negative impact on people's lives and incur high costs for health services and society. It has been suggested that prolonged high levels of protease activity in the later stages of the healing of chronic wounds may be associated with delayed healing. Protease modulating treatments have been developed which seek to modulate protease activity and thereby promote healing in chronic wounds.

OBJECTIVES

To determine whether protease activity is an independent prognostic factor for the healing of venous leg ulcers.

SEARCH METHODS

In February 2018, we searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid Embase and CINAHL.

SELECTION CRITERIA

We included prospective and retrospective longitudinal studies with any follow-up period that recruited people with VLUs and investigated whether protease activity in wound fluid was associated with future healing of VLUs. We included randomised controlled trials (RCTs) analysed as cohort studies, provided interventions were taken into account in the analysis, and case-control studies if there were no available cohort studies. We also included prediction model studies provided they reported separately associations of individual prognostic factors (protease activity) with healing. Studies of any type of protease or combination of proteases were eligible, including proteases from bacteria, and the prognostic factor could be examined as a continuous or categorical variable; any cut-off point was permitted. The primary outcomes were time to healing (survival analysis) and the proportion of people with ulcers completely healed; the secondary outcome was change in ulcer size/rate of wound closure. We extracted unadjusted (simple) and adjusted (multivariable) associations between the prognostic factor and healing.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion at each stage, and undertook data extraction, assessment of risk of bias and GRADE assessment. We collected association statistics where available. No study reported adjusted analyses: instead we collected unadjusted results or calculated association measures from raw data. We calculated risk ratios when both outcome and prognostic factor were dichotomous variables. When the prognostic factor was reported as continuous data and healing outcomes were dichotomous, we either performed regression analysis or analysed the impact of healing on protease levels, analysing as the standardised mean difference. When both prognostic factor and outcome were continuous data, we reported correlation coefficients or calculated them from individual participant data.We displayed all results on forest plots to give an overall visual representation. We planned to conduct meta-analyses where this was appropriate, otherwise we summarised narratively.

MAIN RESULTS

We included 19 studies comprising 21 cohorts involving 646 participants. Only 11 studies (13 cohorts, 522 participants) had data available for analysis. Of these, five were prospective cohort studies, four were RCTs and two had a type of case-control design. Follow-up time ranged from four to 36 weeks. Studies covered 10 different matrix metalloproteases (MMPs) and two serine proteases (human neutrophil elastase and urokinase-type plasminogen activators). Two studies recorded complete healing as an outcome; other studies recorded partial healing measures. There was clinical and methodological heterogeneity across studies; for example, in the definition of healing, the type of protease and its measurement, the distribution of active and bound protease species, the types of treatment and the reporting of results. Therefore, meta-analysis was not performed. No study had conducted multivariable analyses and all included evidence was of very low certainty because of the lack of adjustment for confounders, the high risk of bias for all studies except one, imprecision around the measures of association and inconsistency in the direction of association. Collectively the research indicated complete uncertainty as to the association between protease activity and VLU healing.

AUTHORS' CONCLUSIONS

This review identified very low validity evidence regarding any association between protease activity and VLU healing and there is complete uncertainty regarding the relationship. The review offers information for both future research and systematic review methodology.