Grape seed proanthocyanidins improve lymphatic drainage and blood perfusion in secondary lymphedema models

Abstract

Introduction: Secondary lymphedema (SLE) is a chronic and debilitating condition that frequently arises following cancer treatments, particularly in breast cancer patients. Despite its increasing global prevalence and impact on patients' quality of life, there remains no effective pharmacological treatment for SLE. Grape seed proanthocyanidin extract (GSPE), a compound known for treating venous insufficiency, is hypothesized to enhance lymphatic function and may offer therapeutic value for managing SLE. This study aimed to evaluate the efficacy of GSPE in a rat model of secondary lymphedema.

Methods: Fifteen nine-week-old Sprague-Dawley rats (weighing 250-300 g) were used in this study. Tail lymphedema was surgically induced in 12 rats to model SLE, while 3 rats served as normal controls. The lymphedema-induced rats were randomly assigned to either a treatment group (n=6) or a control group (n=6). The treatment group received intraperitoneal injections of GSPE powder dissolved in saline, whereas the control group received saline alone. Tail volume was measured periodically to monitor edema progression. Lymphatic and blood flow were assessed using near-infrared fluorescence indocyanine green lymphangiography (NIRF-ICGL) and laser Doppler flowmetry imaging (LDFI), respectively. Histological analysis was conducted using hematoxylin and eosin (H&E) staining.

Results: The treatment group demonstrated a significant reduction of edema in the tail compared to the control group. NIRF-ICGL revealed improved lymphatic drainage, while LDFI analysis indicated enhanced blood perfusion in GSPE-treated animals. Histopathological examination showed reduced extracellular matrix deposition and fewer lymphatic abnormalities in the treatment group, suggesting mitigation of tissue fibrosis and lymphatic dysfunction.

Discussion: These findings highlight the therapeutic potential of GSPE in treating secondary lymphedema. The observed improvements in lymphatic drainage, tissue perfusion, and histological features suggest that GSPE may exert beneficial effects beyond its established role in venous insufficiency. Considering the current lack of effective pharmacologic therapies for SLE, GSPE represents a promising candidate for future clinical applications. Further studies are warranted to validate its efficacy and safety in human subjects.

Keywords: Doppler flowmetry; grape seed proanthocyanidin extract (GSPE); lymphangiography; lymphedema; pharmacological treatment; preclinical (in vivo) studies.

Figure 1

The tail diameter ratio of the control and medication group during the follow-up period, and photos of tails in the 8th week. From the 1st week, daily injections of saline (control group) and GSPE solution (medication group) were administered for 2 weeks. Significance was assessed by using Student’s t-test with p-value. Adjusted significance levels are denoted as p < 0.05 (*), p < 0.01 (**), p < 0.005 (***), and p < 0.001 (****).

Figure 2

Representative NIRF-ICGL images of the normal group, (LE) control group, and (LE) medication group. The red triangle indicates the incision line, corresponding to the location marked by the red triangle in the inset tail photo. The green arrow in the medication group image highlights lymphatic flow extending proximally beyond the incision line. P* and D* represent the proximal and distal parts of the tail, respectively.

Figure 3

NIRF-ICGL and visible images (with blue dye) of exposed the LVs obtained after removing the skin of the LE part, where ICG had diffused in the control and medication groups. The red triangle indicates the location of the original incision line. P* and D* represent the proximal and distal parts of the tail, respectively.

Figure 4

Representative LDFI images of the normal, (LE) control, and (LE) medication groups. The red triangle indicates the incision line, corresponding to the location marked by the red arrow in the inset tail photos. The blue color represents weak flux transitioning to red for stronger flux. P* and D* represent the proximal and distal parts of the tail, respectively.

Figure 5

Composite images of LDFI and NIRF-ICGL for the control and medication groups along with a dynamic blood flow flux measured during 3 minutes at a single point on the vein in the LE part. The time-dependent graph illustrates blood flow dynamics. The flux values were normalized based on the minimum and maximum flux values in the measurement. P* and D* represent the proximal and distal parts of the tail, respectively.

Figure 6

H&E-stained cross-sectional images of normal part and LE part tail tissues from the control and medication groups, and a comparison of the averaged dermis thickness ratio between the two groups. Adjusted significance is denoted as p < 0.05 (*) using Student’s t-test.

Figure 7

Comparison of (A) vessel wall thickness in lateral veins and (B) LV (green arrow and area) area between the control group and the medication group. Significance was assessed by using Student’s t-test with p-value. Adjusted significances are denoted as p > 0.05 (ns) and p < 0.001 (****) using Student’s t-test.