The Significance of Pain in Chronic Venous Disease and its Medical Treatment

Ligustrazine mitigates chronic venous disease-induced pain hyperalgesia through desensitization of inflammation-associated TRPA1 activity in DRG

ETHNOPHARMACOLOGICAL RELEVANCE

Ligustrazine, an important active ingredient extracted from Ligusticum chuanxiong hort, has been widely used to cure cardiovascular diseases and exerts an analgesic effect.

AIMS OF THIS STUDY

The aim of this study is to investigate whether ligustrazine mitigates chronic venous disease (CVeD)-induced pain and to explore its underlying mechanisms.

MATERIALS AND METHODS

A mouse model of CVeD was established by vein ligature. Ligustrazine was administered intraperitoneally to CVeD mice for a single injection (20 mg/kg, 100 mg/kg, and 200 mg/kg) or once a day for three weeks (100 mg/kg and 200 mg/kg), and TRPA1 overexpressed HEK 293 cells were treated with ligustrazine (600 μM) in the presence of mustard oil (100 μM) for 2 min. Patch clamp and calcium imaging were used to measure the inhibitory response of ligustrazine on DRG neurons and TRPA1 transfected HEK293 cells.

RESULTS

The present results showed that mice receiving vein ligature surgery exhibited obvious pain hypersensitivity to mechanical, cold and thermal stimuli, whereas ligustrazine significantly reversed the pain hyperalgesia in CVeD mice. Furthermore, ligustrazine desensitized transient receptor potential ankyrin 1 (TRPA1) activity in the dorsal root ganglion (DRG) neurons, resulting in suppressing the DRG neuronal excitability in the CVeD mice. However, ligustrazine could not directly inhibit the response of TRPA1 transfected HEK293 cells to mustard oil. Strikingly, ligustrazine restricted the macrophage infiltration and decreased the mRNA levels of Interleukin-1β (IL-1β) and NOD-like receptor protein 3 (NLRP3) in the DRG neurons of the CVeD mice.

CONCLUSIONS

The present study provided evidence that ligustrazine alleviated pain hypersensitivity to mechanical, cold and thermal stimuli in CVeD mice. Ligustrazine could weaken the activity of TRPA1 in the DRG to mitigate CVeD-induced pain hyperalgesia mainly through inhibition of inflammation. Our findings identify that ligustrazine may be a new therapeutic agent for the treatment of CVeD-induced pain.

Compression therapy, autonomic nervous system, and heart rate variability: A narrative review and our preliminary personal experience

Aims

To highlight the relationship among compression therapy (CT), the autonomic nervous system (ANS) (parasympathetic and sympathetic system), and the heart rate variability (HRV) analysis.

Background

Beyond the typical analgesic and anti-inflammatory effects of CT in patients affected by venous and/or lymphatic diseases, some literature about CT influence on wellbeing has been published as well. More specifically, CT influence on the ANS has been elucidated mostly through HRV application, providing useful quali-quantitative data for scientific and clinical purposes.

Material and Methods

A literature search was performed through several web-based search engines to investigate the available evidence concerning the possible influence of CT on the ANS and on psychoneuroendocrineimmunology. Moreover, we examined literature data regarding HRV use in the assessment of CT. Lastly, a preliminary cross-over study was performed on 10 patients affected by phlebolymphedema of the lower limbs, undergoing CT with 18–21 mmHg stockings for 10 h and investigated by means of HRV.

Results

A CT-based increase of the anti-inflammatory activity of the parasympathetic (vagal) system has been elucidated in most scientific literature. Similarly, CT application has generally resulted in an improvement of HRV, which indicates a beneficial influence on the ANS. In our preliminary experience with compression stockings and HRV, two parasympathetic-based parameters improved by 22.8% and 68.0% after 10 h, whereas they decreased in the same subjects without stockings by 2.7% and 8.2%, during normal breathing. The remaining HRV parameters did not show relevant variations, especially during diaphragmatic breathing.

Conclusions

From literature data and based on our very preliminary experience, it is possible to deduce that CT exerts different effects on the psychobiological parameters of the individual, overall improving HRV and parasympathetic activity. Incorporating both HRV/ANS assessment in phlebolymphology and the beneficial neural action of CT in health care may represent viable options in the future biomedical science.

Efficacy of two micronized purified flavonoid fraction dosing regimens in the pelvic venous pain relief

BACKGROUND

The venoactive drug treatment regimen for pelvic venous disorders (PeVDs) is not finally established. The study aimed at assessing the efficacy of micronized purified flavonoid fraction (MPFF) in a standard or double dose in the pelvic venous pain (PVP) relief in PeVD.

METHODS

We analyzed the treatment efficacy in 125 female patients with PeVD, who were allocated to two groups with MPFF treatment in a regular dose of 1000 mg once daily (OD) for 2 months (N.=65; group 1) or double dose of 1000 mg twice daily for 1 month and then 1000 mg OD for 1 month (N.=60; group 2). Patients underwent clinical examination along with an assessment of the PVP severity using the visual analogue scale (VAS) ranged from 0 to 10 scores, transvaginal and transabdominal duplex ultrasound scanning (DUS), and single-photon emission computed tomography (SPECT) of the pelvic veins with in vivo-labelled red blood cells (RBCs). The groups were different at baseline in the PVP severity (3.4±1.2 vs. 7.3±0.5 scores in groups 1 and 2, accordingly; P=0.012). DUS and SPECT were used to evaluate diameters of gonadal, parametrial, and uterine veins, to assess the presence of reflux in them, to measure blood flow velocity in the internal iliac veins (V<inf>lin IIV</inf>), and to calculate the coefficient of pelvic venous congestion (C<inf>PVC</inf>).

RESULTS

The treatment was associated with a significant reduction in the PVP score from 3.4±1.2 to 1.2±0.2 (P=0.03) when using the standard dose for 2 months and from 7.3±0.5 to 0.8±0.1 (P=0.001) when using the double dose in the 1^st month. The PVP relief was achieved on average after 13.7±0.6 and 3.1±0.8 days in groups 1 and 2, accordingly (P=0.0001 between the groups). At month 2, the C<inf>PVC</inf> reduction was found to be significantly greater in group 2 compared to group 1 (46.6% vs. 25%; P=0.018). Side effects (gastralgia, flatulence) were reported by only 2 (3.3%) patients of group 2.

CONCLUSIONS

The venoactive drug therapy with MPFF is an effective and safe option for the PVP relief in female patients with PeVD. The use of double dose in the 1^st month seems to be appropriate in patients with greater PVP severity but is associated with an increased rate of side effects.