Lymphatic Tissue Bioengineering for the Treatment of Postsurgical Lymphedema

Progenitor Cell Sources for 3D Bioprinting of Lymphatic Vessels and Potential Clinical Application

The lymphatic system maintains tissue fluid homeostasis and it is involved in the transport of nutrients and immunosurveillance. It also plays a pivotal role in both pathological and regenerative processes. Lymphatic development in the embryo occurs by polarization and proliferation of lymphatic endothelial cells from the lymph sacs, that is, lymphangiogenesis. Alternatively, lymphvasculogenesis further contributes to the formation of lymphatic vessels. In adult tissues, lymphatic formation rarely occurs under physiological conditions, being restricted to pathological processes. In lymphvasculogenesis, progenitor cells seem to be a source of lymphatic vessels. Indeed, mesenchymal stem cells, adipose stem cells, endothelial progenitor cells, and colony-forming endothelial cells are able to promote lymphatic regeneration by different mechanisms, such as direct differentiation and paracrine effects. In this review, we summarize what is known on the diverse stem/progenitor cell niches available for the lymphatic system, emphasizing the potential that these cells hold for lymphatic tissue engineering through 3D bioprinting and their translation to clinical application.

Intra-abdominal transplantation of PLGA/PCL/M13 phage electrospun scaffold induces self-assembly of lymphoid tissue-like structure

Lymphoid organs are the main structural components of the immune system. In the current research, the mixture of poly lactic-co-glycolic acid (PLGA), polycaprolactone (PCL), and M13 phage or its RGD-modified form was used in the construction of a fibrillar scaffold using the electrospinning method. The constructs were transplanted intra-abdominally and examined for the formation of lymphoid-like tissues at different time intervals. The confocal and scanning electron microscopy demonstrate that M13 phage-containing scaffolds provide a suitable environment for lymph node-isolated fibroblasts. Morphological analysis demonstrate the formation of lymph node-like tissues in the M13 phage-containing scaffolds after transplantation. Histological analysis confirm both blood and lymph angiogenesis in the implanted construct and migration of inflammatory cells to the M13 phage-containing scaffolds. In addition, flow cytometry and immunohistochemistry analysis showed the homing and compartmentalization of dendritic cells (DCs), B and T lymphocytes within the PLGA/PCL/M13 phage-RGD based scaffolds and similar to what is seen in the mouse lymphoid tissues. It seems that the application of M13 phage could improve the generation of functional lymphoid tissues in the electrospun scaffolds and could be used for lymphoid tissue regeneration.

Biomaterials in the clinical treatment of lymphedema-a systematic review

OBJECTIVE

Lymphedema is a chronic condition caused by impaired lymphatic fluid drainage, resulting in progressive edema. The current mainstay of lymphedema therapy consists of conservative therapy and surgical therapy. In this systematic review, we investigated the novel role of biomaterials in clinical lymphedema therapy and assessed their objective outcomes and the complication rate associated with their use.

METHODS

Studies were identified through systematic review using the Embase and PubMed/MEDLINE databases. Only original articles reporting the use of biomaterials for clinical lymphedema therapy were included. The primary outcome measure was the objective reduction in limb volume after biomaterial use. The secondary outcome measure was the assessment of biomaterial safety.

RESULTS

A total of 354 articles were identified in the first search, of which 10 met our inclusion criteria. These articles described the use of two biomaterials, nanofibrillar collagen scaffolds (NCSs) and silicone tubes (STs), for the treatment of lymphedema. NCS implantation showed an average excess limb volume reduction of 1% to 10.7% and clear evidence of lymphangiogenesis on imaging. No complications were 7documented after NCS implantation. ST implantation showed an average limb volume reduction of 700 to 887 mL and limb circumference reduction of 3.1 to 8 cm in patients with advanced stage lymphedema. Of 177 patients treated with ST implantation, only 11 (6.2%) developed local inflammation.

CONCLUSIONS

Both NCS and ST implantation showed promising limb volume reduction; however, with the scarce literature available, additional research is needed to determine their effectiveness. Both demonstrated good safety profiles, with no complications after NCS implantation and a complication rate equivalent to other similar implants for ST implantation.

Assessment of the Efficiency of Measuring Foot and Ankle Edema with a 3D Portable Scanner

Background: To prospectively evaluate the reliability of a portable optical scanner compared to the water displacement technique for volumetric measurements of the foot and ankle and to compare the acquisition time associated with these two methods. Methods: Foot volume was measured in 29 healthy volunteers (58 feet, 24 females and 5 males) by a 3D scanner (UPOD-S 3D Laser Full-Foot Scanner®) and by water displacement volumetry. Measurements were performed on both feet, up to a height of 10 cm above the ground. The acquisition time for each method was evaluated. The Kolmogorov-Smirnov test, Lin's Concordance Correlation Coefficient, and a Student's t-test were performed. Results: Mean foot volume was 869.7 +/- 165.1 cm³ (3D scanner) versus 867.9 +/- 155.4 cm³ (water-displacement volumetry) (p < 10^-5). The concordance of measurements was 0.93, indicative of a high correlation between the two techniques. Volumes were 47.8 cm³ lower when using the 3D scanner versus water volumetry. After statistically correcting this underestimation, the concordance was improved (0.98, residual bias = -0.03 +/- 35.1 cm³). The mean examination time was 4.2 +/- 1.7 min (3D optical scanner) versus 11.1 +/- 2.9 min (water volumeter) (p < 10^-4). Conclusions: Ankle/foot volumetric measurements performed using this portable 3D scanner are reliable and fast and can be used in clinical practice and research.

Recellularized lymph node scaffolds with human adipose-derived stem cells enhance lymph node regeneration to improve lymphedema

To overcome the limitations of lymphedema treatment, human adipose-derived stem cells (hADSCs) were injected into decellularized lymph nodes to produce a recellularized lymph node-scaffold, and the effect of lymphangiogenesis was investigated in lymphedema animal models. Axillary lymph nodes were harvested from Sprague Dawley rats (7 weeks old, 220-250 g) for decellularization. The decellularized lymph nodes were performed and PKH26-labeled hADSCs (1 × 10⁶/50 µL) were injected in the decellularized lymph node-scaffolds. Forty rats were equally divided into four groups: lymphedema as control group, hADSC group, decellularized lymph node-scaffold group, and recellularized lymph node-scaffold group. The lymphedema model was made by removing inguinal lymph nodes, and hADSCs or scaffolds were transplanted. Histopathological assessments were performed by hematoxylin and eosin and Masson's trichrome staining. Lymphangiogenesis was evaluated by Immunofluorescence staining and western blot. Decellularized lymph nodes showed virtually complete absence of cellular material and maintenance of lymph node architecture. The hADSCs were significantly observed in recellularized lymph node-scaffolds group. The recellularized lymph node-scaffold group was histologically similar to normal lymph nodes. The vascular endothelial growth factor A and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) in immunofluorescence staining were highly expressed in recellularized lymph node-scaffolds group. Also, the expression of LYVE-1 protein significantly increased in recellularized lymph node-scaffold group compared with others. Recellularized lymph node -scaffold had a much better therapeutic effect than stem cells or decellularized lymph node-scaffold alone, and induced stable lymphangiogenesis.