Regulation of Immune Function by the Lymphatic System in Lymphedema

Characteristics and outcomes of lymphaticovenular anastomosis in older patients with bilateral involvement versus younger patients with unilateral involvement in lower extremity lymphedema

OBJECTIVE

We have previously reported that patients with idiopathic primary lymphedema of adult onset can be classified into an older group with bilateral involvement and a younger group with unilateral involvement and that there are significant differences in the characteristics of these groups. The aims of this study were to investigate the features of these two groups further by evaluating the lymphatics while performing lymphaticovenular anastomosis (LVA) and to compare the effectiveness of LVA between the two groups.

METHODS

This study enrolled 74 patients (136 edematous legs) in whom indocyanine green (ICG) lymphography and LVA were performed. The rate of detection and the diameter of the lymphatic vessels were recorded. The lower extremity lymphedema index (the total sum of the squares of the circumference for five areas in each leg divided by the body mass index) was obtained before and 6 months after LVA. The rate of improvement in the affected lower limbs after LVA was also calculated.

RESULTS

The clinical lymphedema pattern was determined to be bilateral in 62 patients and unilateral in 12. Patients with bilateral lymphedema were significantly older than those with unilateral lymphedema (77.1 ± 7.8 years vs 55.5 ± 12.77 years; P < .01). A linear pattern was seen in 23 patients (46 legs), a low enhancement (LE) pattern in 12 patients (24 legs), a distal dermal backflow (dDB) pattern in 20 patients (40 legs), and an extended dermal backflow (eDB) pattern in 7 patients (14 legs). The lymphedema was unilateral in 12 patients (12 legs). There were significant between-group differences in lymphatic diameter in relation to lower leg area: linear (0.9 ± 0.1 mm) vs dDB (0.7 ± 0.2 mm), linear vs eDB (0.7 ± 0.2 mm), linear vs unilateral (0.5 ± 0.1 mm), LE (0.9 ± 0.2 mm) vs dDB, LE vs eDB, LE vs unilateral, and dDB vs unilateral, P < .01; and eDB vs unilateral, P < .05. There were also significant between-group differences in the rate of improvement in the lower extremity lymphedema index according to the ICG lymphography pattern and laterality: linear (10.5% ± 2.4%) vs unilateral (6.7% ± 0.6%), LE (10.4% ± 1.5%) vs unilateral, dDB (11.0% ± 1.3%) vs eDB (8.9% ± 1.5%), and dDB vs unilateral, P < .01; linear vs eDB, P < .05; and eDB vs unilateral, P < .05.

CONCLUSIONS

The lymphatic vessel diameter tended to be greater in older patients with bilateral lymphedema than in younger patients with unilateral lymphedema. The rate of detection and improvement tended to decrease with worsening of the ICG lymphography pattern. LVA is thought to be more effective in older patients with early-stage bilateral lower leg lymphedema than in their younger counterparts with late-stage unilateral lymphedema.

Molecular pathways involved in lymphedema: Hydroxytyrosol as a candidate natural compound for treating the effects of lymph accumulation

Lymphedema is a chronic accumulation of interstitial fluid due to inefficient lymph drainage. Major causes of lymphedema are malformations of lymphatic vessels, trauma, toxic damage and surgery. The swelling typically affects the limbs. Lymphedema may be primary, caused by genetic mutations and relatively rare, or secondary (acquired), due to external causes such as infections or surgery. Fluid accumulation induces pathological changes: activation of the inflammatory cascade, immune cell infiltration, tissue fibrosis, adipose accumulation. We focused on the inflammatory phenotype mediated by leukotriene B4, a lipid mediator of the inflammatory pathway, and the potential therapeutic effect of hydroxytyrosol. We conducted an electronic search in PubMed using "lymphedema", "lymphedema pathway", "hydroxytyrosol" as keywords. We found that lymphedema deregulates at least six molecular pathways and that hydroxytyrosol, a compound with antioxidant activity, can improve endothelial dysfunction, hemostatic and lipid profiles, and decrease oxidative stress and inflammation through inhibition of leukotriene B4 activity. This review is the first to highlight the possibility of using hydroxytyrosol to treat the secondary effects of lymphedema, especially inflammation. The possible effects of hydroxytyrosol on lymphedema should be tested in vitro and in vivo to find the best way to treat patients with lymphedema in order to improve their health status.

Opposing roles of endothelial and leukocyte-expressed IL-7Rα in the regulation of psoriasis-like skin inflammation

The interleukin 7 receptor alpha chain (IL-7Rα) is predominately expressed by lymphocytes, and activation by its ligand IL-7 supports the development and maintenance of T cells and boosts T-cell mediated immunity. We recently reported that lymphatic endothelial cells (LECs) in dermal lymphatics also express IL-7 and its receptor chains (IL-7Rα and CD132) and that IL-7 supports lymphatic drainage. This suggested that activation of IL-7Rα signaling in lymphatics could exert inflammation-resolving activity, by promoting the clearance of excess tissue fluid. Here we investigated how the potentially opposing effects of IL-7Rα signaling in immune cells and in the lymphatic vasculature would affect the development and progression of psoriasis-like skin inflammation. We found that during acute and chronic skin inflammation mice with an endothelial-specific deletion of IL-7Rα (IL-7Rα^ΔEC mice) developed more edema compared to control mice, as a consequence of impaired lymphatic drainage. However, systemic treatment of wild-type mice with IL-7 exacerbated edema and immune cell infiltration in spite of increasing lymphatic drainage, whereas treatment with IL-7Rα blocking antibody ameliorated inflammatory symptoms. These data identify IL-7Rα signaling as a new pathway in psoriasis-like skin inflammation and show that its pro-inflammatory effects on the immune compartment override its anti-inflammatory, drainage-enhancing effects on the endothelium.

[Lower limb lymphedema: A rare manifestation of spondyloarthropathy]

INTRODUCTION

Spondyloarthritis include articular (axial, peripheral or enthesitic) and extra-articular manifestations. We reported three cases of limb lymphedema associated with a spondyloarthritis.

CASE REPORTS

We report on two men and one female aged of 75, 52 and 39 years, respectively. The rheumatic disease was an ankylosing spondylitis HLA B27 positive in two patients and a psoriatic arthritis in the remaining one. Lymphedema, always unilateral, confirmed by the Stemmer's sign, involved the whole lower limb (n=2) or only the foot and calf (n=1). Lymphedema occurred 3 months, 40 and 9 years after the onset of spondyloarthritis. Lower limb lymphoscintigraphy was abnormal in all cases: decrease (n=2) or absence (n=1) of inguinal lymph node uptake, and visualization of the popliteal lymph node related to deep lymphatic pathway (n=1). Treatment of the spondyloarthritis did not improve lymphedema. Both the low-stretch bandage and elastic compression treatment allowed its reduction and stabilization.

CONCLUSION

Limb lymphedema is a rare extra-articular manifestation of spondyloarthritis. Its course appears to be independent of joint disease. Its management is specific and should be associated to that of the rheumatologic disorder.

Lymphedema microsurgery reduces the rate of implant removal for patients who have pre-existing lymphedema and total knee arthroplasty for knee osteoarthritis

INTRODUCTION

Patients with pre-existing lymphedema who undergo total knee arthroplasty (TKA) for osteoarthritis (OA) are at high risk for periprosthetic joint infection. This complication usually requires removal of the implant. This study aimed to investigate whether surgical treatment of lymphedema reduces the rate of prosthesis removal in such patients.

MATERIALS AND METHODS

We retrospectively reviewed our prospective database of patient information collected between January 2009 and December 2018. A total of 348 cases of lower extremity lymphedema were reviewed, and those who underwent total knee TKA for OA of the knee were included. Patient demographics, clinical data, lymphedema surgical history, and TKA surgical history including any episodes of removal were collected and analyzed.

RESULTS

There were nine of 15 lymphedema patients with knee OA who subsequently underwent TKA. The mean patient age was 70.4 ± 7.1 years. A total of 18 TKAs were performed in nine patients. The knee prosthesis removal rate was 66.7% (12/18). The prosthesis removal rate was 40% (2/5) in patients who underwent lymphedema microsurgery vs 76.9% (10/13) for those who did not (P = .03).

CONCLUSIONS

Pre-existing lymphedema is associated with a high rate of knee prosthesis removal. Lymphedema microsurgery reduced the removal rate of knee prostheses. We recommend that lymphedema microsurgery be considered for patients who require TKA as a treatment for of the knee.