Increased hyaluronan expression at distinct time points in acute lymphedema

Improved lymphangiogenesis around vascularized lymph node flaps by periodic injection of hyaluronidase in a rodent model

Vascularized lymph node transfer (VLNT) is an advanced surgical approach for secondary lymphedema (SLE) treatment, but tissue fibrosis around the lymph node flap (VLNF) inhibiting lymphangiogenesis is the biggest challenge undermining its therapeutic efficacy. This study explored the effects of periodic hyaluronidase (HLD) injection in reducing fibrosis and promoting lymphangiogenesis in 52 Sprague-Dawley rats with a VLNF over 13 weeks. The results demonstrated that HLD administration significantly enhanced swelling reduction, lymphatic drainage efficiency, and lymphatic vessel regeneration, with up to a 26% decrease in tissue fibrosis around the VLNF. These findings suggest that combining VLNT with periodic injections of HLD could substantially improve SLE treatment outcomes in clinical settings. It offers a promising direction for future therapeutic strategies and drug development aimed at increasing the efficacy of surgical treatment for SLE patients.

Lower limb lymphedema and cellulitis as a complication of COVID-19 vaccine: A case report

A 68-year-old man without complications following his first dose of Sinopharm (BBIBP-CorV) COVID-19 vaccine developed left foot and ankle edema, extending to his left leg 3 days after his second dose. Color-Doppler sonography and lymphoscintigraphy showed extensive soft tissue swelling and fat edema in both legs, proposing lymphatic drainage disorder.

Lipedema: Insights into Morphology, Pathophysiology, and Challenges

Lipedema is an adipofascial disorder that almost exclusively affects women. Lipedema leads to chronic pain, swelling, and other discomforts due to the bilateral and asymmetrical expansion of subcutaneous adipose tissue. Although various distinctive morphological characteristics, such as the hyperproliferation of fat cells, fibrosis, and inflammation, have been characterized in the progression of lipedema, the mechanisms underlying these changes have not yet been fully investigated. In addition, it is challenging to reduce the excessive fat in lipedema patients using conventional weight-loss techniques, such as lifestyle (diet and exercise) changes, bariatric surgery, and pharmacological interventions. Therefore, lipedema patients also go through additional psychosocial distress in the absence of permanent treatment. Research to understand the pathology of lipedema is still in its infancy, but promising markers derived from exosome, cytokine, lipidomic, and metabolomic profiling studies suggest a condition distinct from obesity and lymphedema. Although genetics seems to be a substantial cause of lipedema, due to the small number of patients involved in such studies, the extrapolation of data at a broader scale is challenging. With the current lack of etiology-guided treatments for lipedema, the discovery of new promising biomarkers could provide potential solutions to combat this complex disease. This review aims to address the morphological phenotype of lipedema fat, as well as its unclear pathophysiology, with a primary emphasis on excessive interstitial fluid, extracellular matrix remodeling, and lymphatic and vasculature dysfunction. The potential mechanisms, genetic implications, and proposed biomarkers for lipedema are further discussed in detail. Finally, we mention the challenges related to lipedema and emphasize the prospects of technological interventions to benefit the lipedema community in the future.

Frequent Onsets of Cellulitis in Lower Limbs with Lymphedema Following COVID-19 mRNA Vaccination

Four patients with secondary lower limb lymphedema developed cellulitis at their lymphedema lesion following COVID-19 mRNA vaccinations. They did not develop adverse effects at their vaccination site. All the patients were Japanese females aged <60 years. Three patients developed cellulitis following the first vaccination. The date of onset of cellulitis following the first vaccination varied from 0 to 21 days. Two received BNT162b2 mRNA vaccines and the others received mRNA-1273 vaccines. All the patients were treated with oral antibiotics and recovered. Two patients had repeated cellulitis. The patients with the repeated development of cellulitis could not perform good skincare. One patient had joint contractures in their lower limbs and could not reach her lymphedema lesions, and the other patient could not master the skincare. According to previous studies, the development of cellulitis following vaccination was rare. In this study, four patients aged <60 years developed cellulitis among the eight patients that regularly visited our hospital for rehabilitation for their lower limb lymphedema. In patients with lymphedema, prolonged inflammation may impair lymphatic functions and worsen edema. Therefore, at the time of vaccination, we should keep in mind the prevention and immediate management of cellulitis using intensive skincare and antibiotic treatment.

Standard of care for lipedema in the United States

Background

Lipedema is a loose connective tissue disease predominantly in women identified by increased nodular and fibrotic adipose tissue on the buttocks, hips and limbs that develops at times of hormone, weight and shape change including puberty, pregnancy, and menopause. Lipedema tissue may be very painful and can severely impair mobility. Non-lipedema obesity, lymphedema, venous disease, and hypermobile joints are comorbidities. Lipedema tissue is difficult to reduce by diet, exercise, or bariatric surgery.

Methods

This paper is a consensus guideline on lipedema written by a US committee following the Delphi Method. Consensus statements are rated for strength using the GRADE system.

Results

Eighty-five consensus statements outline lipedema pathophysiology, and medical, surgical, vascular, and other therapeutic recommendations. Future research topics are suggested.

Conclusion

These guidelines improve the understanding of the loose connective tissue disease, lipedema, to advance our understanding towards early diagnosis, treatments, and ultimately a cure for affected individuals.

Hyaluronidase inhibition accelerates functional recovery from stroke in the mouse brain

Perineuronal nets (PNNs) are presumed to limit plasticity in adult animals. Ischaemic stroke results in the massive breakdown of PNNs resulting in rejuvenating states of neuronal plasticity, but the mechanisms of this phenomenon are largely unknown. As hyaluronic acid (HA) is the structural backbone of PNNs, we hypothesized that these changes are a consequence of the altered expression of HA metabolism enzymes. Additionally, we investigated whether early hyaluronidase inhibition interferes with post-stroke PNN reduction and behavioural recovery. We investigated the mRNA/protein expression of these enzymes in the perilesional, remote and contralateral cortical regions in mice at different time points after photothrombosis, using quantitative real-time polymerase chain reaction and immunofluorescence. A skilled reaching test was employed to test hyaluronidase inhibitor L-ascorbic acid 6-hexadecanoate influence on post-stroke recovery. We found the simultaneous up-regulation of mRNA of HA synthesizing and degrading enzymes in the perilesional area early after stroke, suggesting an acceleration of HA turnover in ischaemic animals. Immunostaining revealed differential cellular localization of enzymes, with hyaluronidase 1 in astrocytes and hyaluronan synthase 2 in astrocytes and neurons, and post-stroke up-regulation of both of them in astrocytes. β-glucuronidase was observed in neurons but post-stroke up-regulation occurred in microglia. Inhibition of hyaluronidase activity early after stroke resulted in improved performance in skilled reaching test, without affecting the numbers of PNNs. These results suggest that after stroke, a substantial reorganization of polysaccharide content occurs, and interfering with this process at early time has a beneficial effect on recovery.

The multicomponent medication lymphomyosot improves the outcome of experimental lymphedema

BACKGROUND

Secondary lymphedema is a life-long disease of painful tissue swelling that often follows axillary lymph node dissection to treat breast cancer. It is hypothesized that poor lymphatic regeneration across the obstructive scar tissue during the wound healing process may predispose the tissue to swell at a later date. Treatment for lymphedema remains suboptimal and is in most cases palliative. The purpose of this study was to evaluate the ability of Lymphomyosot to treat tissue swelling and promote lymphangiogenesis in experimental models of murine lymphedema.

METHODS

Experimental models of mouse lymphedema were injected with varied amounts of Lymphomyosot and saline as control. Measurements of tail swelling and wound closure were taken and compared amongst the groups. Three separate groups of mice were analyzed for lymphatic capillary migration, lymphatic vessel regeneration, and macrophage recruitment.

RESULTS

Lymphomyosot significantly reduced swelling and increased the rate of surgical wound closure. Lymphomyosot did not increase the migration of lymph capillaries in a mouse tail skin regeneration model or regeneration of lymph vessels following murine axillary lymph node dissection.

CONCLUSIONS

Lymphomyosot may act through inflammatory and wound repair pathways to reduce experimental lymphedema. Its ability to regulate inflammation as well as assist in tissue repair and extracellular formation may allow for the production of a scar-free matrix bridge through which migrating cells and accumulated interstitial fluid can freely spread.