Estimation of Arm Adipose Tissue Quotient Using Segmental Bioimpedance Spectroscopy

Overview of Lymphedema for Physicians and Other Clinicians: A Review of Fundamental Concepts

Lymphedema has historically been underrated in clinical practice, education, and scholarship to the detriment of many patients with this chronic, debilitating condition. The mechanical insufficiency of the lymphatic system causes the abnormal accumulation of protein-rich fluid in the interstitium, which triggers a cascade of adverse consequences such as fat deposition and fibrosis. As the condition progresses, patients present with extremity heaviness, itchiness, skin infections, and, in later stages, dermal fibrosis, skin papillomas, acanthosis, and other trophic skin changes. Correspondingly, lymphedema results in psychological morbidity, including anxiety, depression, social avoidance, and a decreased quality of life, encompassing emotional, functional, physical, and social domains. For this review, we conducted a literature search using PubMed and EMBASE and herein summarize the evidence related to the fundamental concepts of lymphedema. This article aims to raise awareness of this serious condition and outline and review the fundamental concepts of lymphedema.

Relationship Between the Circumference Difference and Findings of Indocyanine Green Lymphography in Breast Cancer-Related Lymphedema

BACKGROUND

Breast cancer-related lymphedema (BCRL) is a common complication. Indocyanine green (ICG) lymphography has been performed to assess lymphatic functionality. We found that some BCRL patients had a difference in circumference in partial regions only. The purpose of this study was to evaluate the patients with BCRL about the correlation between the difference in circumference and the findings of ICG lymphography.

METHODS

One hundred fifty-five patients with unilateral BCRL were enrolled in this study. We evaluated the differences in circumference taken at 4 parts on the upper limb (at around the wrist, forearm, elbow, and brachium). The difference in circumference was evaluated between the affected part (Caf) and the unaffected part (Cun). We calculated the circumference difference rate (CDR) as follows: CDR = 100 (Caf - Cun)/Caf. First, we classified each part of all BCRL patients (620 parts) based on the findings of ICG lymphography (linear, collateral, dermal back flow [DBF], and no enhancement) and evaluated the correlation. Second, in the patients with partial volume change, we compared the mean CDR in each part.

RESULTS

One hundred six parts were of a linear pattern, 31 parts were collateral, 350 parts were DBF, and 133 parts had no enhancement. The mean CDR of each finding was 3.3% in linear, 4.0% in collateral, 9.6% in DBF, and 9.4% in no enhancement. There was no significant difference between linear and collateral (P = 0.62), DBF, and no enhancement (P = 0.89) patterns. However, there was a significant difference between linear or collateral and DBF or no enhancement (all P < 0.001). In the 22 patients with distal DBF and proximal linear, the CDR was significantly higher in the forearm compared with the brachium (6.4% and 3.0%; P = 0.003). In the 26 patients with distal linear and proximal DBF, the CDR was significantly higher in the brachium compared with the forearm (4.3% and 7.7%; P = 0.005).

CONCLUSIONS

There was a significant correlation between the difference in circumference and the severity of ICG findings.

Use of bioimpedance spectroscopy for prospective surveillance and early diagnosis of breast cancer-related lymphedema

BACKGROUND

Bioimpedance spectroscopy has been suggested as a useful tool for early diagnosis of breast cancer-related lymphedema (BCRL). We aimed to describe the outcomes of published studies that evaluated bioimpedance analysis as a method for prospective surveillance and early diagnosis of BCRL.

METHODS

We queried the PubMed, Ovid Medline, and EMBASE databases to identify studies that evaluated use of bioimpedance spectroscopy as a diagnostic tool. We used the keywords "bioimpedance" AND ("lymphedema" OR "lymphoedema") in the search. Only English-language studies that reported quantitative outcomes for patients with BCRL were included.

RESULTS

Of 152, 235 and 116 identified articles in PubMed, Ovid Medline and EMBASE databases, only 22 were included. Use of bioimpedance analysis for prospective surveillance has been shown to prevent chronic BCRL. All the cross-sectional and retrospective studies that evaluated bioimpedance for diagnosis of BCRL reported significantly different L-Dex scores between lymphedema patients and healthy participants; in addition, bioimpedance scores were positively correlated with volume of lymphedema.

CONCLUSION

Bioimpedance analysis is a potential tool with demonstrated benefits for prevention of chronic BCRL and may be an economic and great alternative for early diagnosis of BCRL.

Inflammation Precedes Fat Deposition in an Experimental Model of Lymphedema

Background: Chronic lymphedema is a common complication of lymphatic obstruction, particularly after cancer treatment, characterized by an increased volume of the affected extremity, partly caused by the accumulation of excessive adipose tissue. The relationship between lymph vessels' obstruction and fat deposit is, however, poorly understood. Objective: Our central hypothesis was that the inflammatory process caused by lymph stasis precedes the adipocyte differentiation and fat deposition. Methods and Results: We used a modified mouse tail model to produce secondary lymphedema. Animals were treated with dexamethasone, or the procedure was performed in nitric oxide synthase 2 (NOS2)-deficient mice to evaluate the role of inflammation in lymphedema formation. Adipose tissue (Lipin) and inflammatory markers (IL-6, MCP-1, and F4-80) were analyzed in histological samples and by quantitative polymerase chain reaction. We observed an increased deposition of fat into the affected area that starts 3 weeks after lymph vessel ligation; it further increased after 6 weeks. Genes involved in the inflammatory process were upregulated before adipocyte maturation. Treatment with dexamethasone or the use of inducible nitric oxide synthase knockout mice blocked the inflammatory reaction and inhibited the accumulation of fat distal to the lymphatic obstruction. Conclusion: In the modified mouse tail lymphedema, inflammation precedes adipogenesis. Our data suggest that MCP-1 and nitric oxide may be potential targets for lymphedema management.