Volumetric analysis of the terminal ductal lobular unit architecture and cell phenotypes in the human breast.

The major lactiferous ducts of the human breast branch out and end at terminal ductal lobular units (TDLUs). Despite their functional and clinical importance, the three-dimensional (3D) architecture of TDLUs has remained undetermined. Our quantitative and volumetric imaging of healthy human breast tissue demonstrates that highly branched TDLUs, which exhibit increased proliferation, are uncommon in the resting tissue regardless of donor age, parity, or hormonal contraception. Overall, TDLUs have a consistent shape and branch parameters, and they contain a main subtree that dominates in bifurcation events and exhibits a more duct-like keratin expression pattern. Simulation of TDLU branching morphogenesis in three dimensions suggests that evolutionarily conserved mechanisms regulate mammary gland branching in humans and mice despite their anatomical differences. In all, our data provide structural insight into 3D anatomy and branching of the human breast and exemplify the power of volumetric imaging in gaining a deeper understanding of breast biology.

Donor-site safety in microvascular lymph node transfer for breast cancer-related lymphedema using reverse lymphatic mapping-A prospective study.

BACKGROUND: Vascularized lymph node transfer (VLNT) is one option among other surgical treatments in the management of breast cancer-related lymphedema (BCRL). The cause of concern regarding VLNT harvested from the groin has been the potential development of secondary lower-extremity lymphedema. This study explored the risks associated with donor-site morbidity following groin VLNT, with or without concomitant breast reconstruction. METHOD: The cohort comprised data from the Lymfactin® Phase I and II trials, conducted from 2016 to 2019, that used perioperative reverse lymphatic mapping. The volume of the lower extremities was measured preoperatively and at 3, 6, and 12 months postoperative, and the adverse events were documented during study visits. RESULTS: Altogether, 51 women with a mean age of 55.5 years were recruited. The mean duration of BCRL was 31.8 months. Among these, 25 (49%) underwent VLNT (VLNT-group) and 26 (51%) underwent VLNT in combination with breast reconstruction (VLNT-BR group). The groups were similar in terms of age, (p = 0.766), BMI (p = 0.316), and duration of BCRL (p = 0.994). Across a period of one year, the volume difference between the lower extremities changed by 22.6 ml (range: -813 to 860.2 ml) (p = 0.067). None of the patients had lower-extremity volume difference exceeding 10% at the 12-month follow-up visit. The most frequent adverse events were postoperative pain (17.7%), wound healing issues (11.8%), and seroma formation (11.8%). Most adverse events (64.6%) were classified as minor. CONCLUSIONS: This prospective study demonstrated that groin VLNT with reverse lymphatic mapping appears safe and does not increase the risk of secondary donor-site lymphedema within one year postoperatively.

Phase II study shows potential benefit of adenoviral vascular endothelial growth factor C (VEGF-C) and lymph node transfer in lymphedema.

BACKGROUND: Breast cancer-related lymphedema (BCRL) is a common complication lacking medical treatment. Lymfactin® is an adenovirus type 5-based gene therapy and prolymphangiogenic growth factor vector that induces vascular endothelial growth factor C (VEGF-C) expression. Our aim was to evaluate the therapeutic effect of Lymfactin® with vascularized lymph node transfer (VLNT). METHODS: This Phase II, double-blind, placebo-controlled, randomized multicenter study evaluated the efficacy and safety of Lymfactin® in combination with VLNT. The primary endpoints were edema volume, quality of life (LyQoLI), and lymphoscintigraphy. All adverse events were recorded. A mixed model of repeated measures analysis of covariance was performed. This study was a continuation of a previous Phase I Lymfactin® study. RESULTS: Thirty-nine patients with BCRL were recruited between June 2018 and December 2019 and randomized to receive either Lymfactin® (n = 20) or placebo (n = 19). The primary endpoints showed a positive effect of VLNT in both groups compared to the baseline, but without statistical differences between groups at 12 months. Additionally, greater improvements were observed in the tissue dielectric constant ratios measuring skin interstitial fluid levels in the Lymfactin® group compared to the placebo group (p = 0.020). No differences in adverse events were detected between the groups. CONCLUSIONS: This study was one of the few studies to objectively show a positive effect of VLNT in a prospective clinical multicenter setting. It was also the first-ever randomized prospective clinical study showing a quantitatively positive effect of a medical therapy on the edema of lymphedema although failing to show differences between groups in primary outcome measures.

IGFBP2 secretion by mammary adipocytes limits breast cancer invasion.

The progression of noninvasive ductal carcinoma in situ to invasive ductal carcinoma for patients with breast cancer results in a significantly poorer prognosis and is the precursor to metastatic disease. In this work, we have identified insulin-like growth factor-binding protein 2 (IGFBP2) as a potent adipocrine factor secreted by healthy breast adipocytes that acts as a barrier against invasive progression. In line with this role, adipocytes differentiated from patient-derived stromal cells were found to secrete IGFBP2, which significantly inhibited breast cancer invasion. This occurred through binding and sequestration of cancer-derived IGF-II. Moreover, depletion of IGF-II in invading cancer cells using small interfering RNAs or an IGF-II-neutralizing antibody ablated breast cancer invasion, highlighting the importance of IGF-II autocrine signaling for breast cancer invasive progression. Given the abundance of adipocytes in the healthy breast, this work exposes the important role they play in suppressing cancer progression and may help expound upon the link between increased mammary density and poorer prognosis.

MYO10-filopodia support basement membranes at pre-invasive tumor boundaries.

Ductal carcinoma in situ (DCIS) is a pre-invasive stage of breast cancer. During invasion, the encapsulating DCIS basement membrane (BM) is compromised, and tumor cells invade the surrounding stroma. The mechanisms that regulate functional epithelial BMs in vivo are poorly understood. Myosin-X (MYO10) is a filopodia-inducing protein associated with metastasis and poor clinical outcome in invasive breast cancer (IBC). We identify elevated MYO10 expression in human DCIS and IBC, and this suggests links with disease progression. MYO10 promotes filopodia formation and cell invasion in vitro and cancer-cell dissemination from progressively invasive human DCIS xenografts. However, MYO10-depleted xenografts are more invasive. These lesions exhibit compromised BMs, poorly defined borders, and increased cancer-cell dispersal and EMT-marker-positive cells. In addition, cancer spheroids are dependent on MYO10-filopodia to generate a near-continuous extracellular matrix boundary. Thus, MYO10 is protective in early-stage breast cancer, correlating with tumor-limiting BMs, and pro-invasive at later stages, facilitating cancer-cell dissemination.

Phase 1 Lymfactin® Study: 24-month Efficacy and Safety Results of Combined Adenoviral VEGF-C and Lymph Node Transfer Treatment for Upper Extremity Lymphedema.

BACKGROUND: Lymphedema is a common problem after breast cancer treatment. Lymfactin® is a prolymphangiogenic growth factor vector inducing the expression of human vascular endothelial growth factor C (VEGF-C). It promotes growth and repair of lymphatic vessels. METHODS: Lymfactin® was combined with microvascular lymph node transfer surgery (VLNT) to study the safety and efficacy of the treatment in breast cancer-related upper limb lymphedema (BCRL) patients. This is a continuation study with a 3 year efficacy and 5 year safety follow-up. RESULTS: Fifteen patients were recruited in the study between June 2016 and February 2018. Three patients received a lower dose (1 × 1010 viral particles (vp)), and 12 patients received a higher dose (1 × 1011 vp) of Lymfactin®, respectively. In the higher dose group, the reduction of excess arm volume was on average 46% after the 12 month follow-up, and the transport index was improved in 7/12 patients. At baseline, removal of the compression garment for 7 days resulted in significant arm swelling (105.7±161.0 ml, p=0.0253). However, at 12 months, there was less and not significant swelling after removal of the garment (84.4±143.0 ml, p=0.0682). Lymphedema Quality of Life Inventory (LQOLI or LyQLI) questionnaire showed significant and sustained improvement of quality of life. CONCLUSIONS: During 24 months' of follow-up, the results indicate that Lymfactin® is well tolerated. The most promising findings were a 46% reduction in excess arm volume and a nonsignificant volume increase after garment removal at 12 months, suggesting that there is potential for the reduction of lymphedema.

Low TGF-ß1 in Wound Exudate Predicts Surgical Site Infection After Axillary Lymph Node Dissection.

PURPOSE: Surgical site infection (SSI) after axillary lymph node dissection (ALND) for breast cancer increases morbidity and delays the onset of adjuvant treatment. Only a few studies have investigated the feasibility of wound exudate analysis in SSI prediction. This study assessed changes in cytokine levels in postsurgical wound exudate after ALND and examined their predictive value for the early diagnosis of SSI. METHODS: An observational prospective pilot study was conducted in 47 patients with breast cancer undergoing ALND. Wound exudate samples were collected on the first and sixth postoperative days (POD). Interleukin (IL)-1α, IL-1ß, IL-4, IL-10, IL-13, tumor necrosis factor alpha (TNF-α), transforming growth factor beta1 (TGF-ß1) and vascular endothelial growth factor (VEGF) C and D levels were measured by immunoassay. Patients were followed to detect SSI. RESULTS: SSI was diagnosed in 8/47 (17.0%) patients. Four SSI patients were hospitalized and treated with intravenous antibiotics. The concentration of TGF-ß1 in wound exudate was significantly lower on POD#1 in the SSI group compared to the no SSI group (p=0.008). The receiving operator characteristics (ROC) curve for TGF-ß1 showed an area under curve of 0.773 (p=0.0149) indicating good diagnostic potential. On POD#6, the concentration of TGF-ß1 remained significantly lower (p=0.043) and the concentrations of IL-10 (p=0.000) and IL-1ß (0.004) significantly higher in the SSI group compared to the no SSI group. CONCLUSION: To our knowledge, this is the first study suggesting a predictive role of wound exudate TGF-ß1 levels for SSI. Our results suggest that the risk for SSI can be detected already on POD#1 and that the assessment of TGF-ß1 levels in the wound exudate after ALND can provide a usefull method for the early detection of SSI. The key findings of this pilot study warrant verification in a larger patient population.

CC chemokine ligand 2 (CCL2) stimulates aromatase gene expression in mammary adipose tissue.

Obesity is a risk factor for postmenopausal breast cancer. Obesity-related inflammation upregulates aromatase expression, the rate-limiting enzyme for estrogen synthesis, in breast adipose tissue (BAT), increasing estrogen production and cancer risk. The regulation of aromatase gene (CYP19A1) in BAT is complex, and the mechanisms linking obesity and aromatase dysregulation are not fully understood. An obesity-associated factor that could regulate aromatase is the CC chemokine ligand (CCL) 2, a pro-inflammatory factor that also activates signaling pathways implicated in CYP19A1 transcription. By using human primary breast adipose stromal cells (ASCs) and aromatase reporter (hARO-Luc) mouse mammary adipose explants, we demonstrated that CCL2 enhances the glucocorticoid-mediated CYP19A1 transcription. The potential mechanism involves the activation of PI.4 via ERK1/2 pathway. We also showed that CCL2 contributes to the pro-inflammatory milieu and aromatase expression in obesity, evidenced by increased expression of CCL2 and CYP19A1 in mammary tissues from obese hARO-Luc mice, and subcutaneous adipose tissue from obese women. In summary, our results indicate that postmenopausal obesity may promote CCL2 production in BAT, leading to exacerbation of the menopause-related inflammatory state and further stimulation of local aromatase and estrogens. These results provide new insights into the regulation of aromatase and may aid in finding approaches to prevent breast cancer.

Long-term Results of Microvascular Lymph Node Transfer: Correlation of Preoperative Factors and Operation Outcome.

Our objective was to analyze whether a correlation could be observed between preoperative factors and microvascular lymph node transfer outcome after long-term follow-up. METHODS: We included 67 patients in this retrospective case series. The incidence of cellulitis, the difference of arm circumference, the use of the compression garments both preoperatively and postoperatively, and subjective symptoms, such as pain, were analyzed. Volumetry and lymphoscintigraphy results were also analyzed in a subgroup of patients. We correlated preoperative factors with postoperative results. RESULTS: After 70 ± 17 months of follow-up, 42% of the patients were able to discontinue the use of compression garments. The subjective pain symptoms were reduced in 75% of the patients. The incidence of cellulitis was reduced from preoperative 0.20 ± 0.55/y to postoperative 0.02 ± 0.08/y. As a novel finding, the patients with preoperative cellulitis were more likely to continue the use of the compression garments. CONCLUSIONS: The surgery is beneficial to most studied lymphedema patients, although it is not the cure for all patients. The incidence of cellulitis was reduced, and further, the presence of preoperative cellulitis seems to affect the outcome of the operation.

Phase 1 LymfactinⓇ Study: Short-term Safety of Combined Adenoviral VEGF-C and Lymph Node Transfer Treatment for Upper Extremity Lymphedema.

OBJECTIVE: To study the safety and tolerability of LymfactinⓇ treatment combined with microvascular lymph node transfer surgery in patients with upper limb lymphedema. BACKGROUND: Upper limb lymphedema is a common clinical challenge after breast cancer surgery and/or radiotherapy. LymfactinⓇ is an adenovirus type 5-based gene therapy involving expression of human vascular endothelial growth factor C (VEGF-C) in the damaged tissue. It aims to correct deficient lymphatic flow by promoting the growth and repair of lymphatic vessels. METHODS: In Phase I, LymfactinⓇ was combined with microvascular lymph node transfer surgery to study the safety and tolerability of LymfactinⓇ and the biodistribution of the viral vector in patients with upper limb lymphedema. RESULTS: Fifteen patients with breast cancer-associated secondary lymphedema of the upper arm were recruited between December 2016 and February 2018. Three patients received a lower dose (1 × 1010) and 12 a higher dose (1 × 1011) of viral particles, respectively. No dose-limiting toxicities were observed, and the study was completed with the pre-determined maximum dose. Commonly reported adverse events during the 12-month follow-up were common cold, fever, gastroenteritis, pain in the operation area, headache, muscle ache and elevated liver enzymes. Serious adverse events consisted of two erysipelas infections in the lymphedema arm (requiring hospitalization) and one hematoma of the flap donor site. CONCLUSIONS: After 12 months' follow-up, results indicate that LymfactinⓇ is well tolerated. The study continues with a 36-months efficacy and 5 years safety follow-up of the patients. The oncological safety aspects of LymfactinⓇ will require a longer follow-up period.

Preperitoneal Fat Grafting Inhibits the Formation of Intra-abdominal Adhesions in Mice.

BACKGROUND: Adhesion formation contributes to postoperative complications in abdominal and gynaecological surgery. Thus far, the prevention and treatment strategies have focused on mechanical barriers in solid and liquid form, but these methods are not in routine use. As autologous fat grafting has become popular in treatment of hypertrophic scars because of its immunomodulatory effects, we postulated that fat grafting could also prevent peritoneal adhesion through similar mechanisms. METHODS: This was a control versus intervention study to evaluate the effect of fat grafting in the prevention on peritoneal adhesion formation. An experimental mouse model for moderate and extensive peritoneal adhesions was used (n = 4-6 mice/group). Adhesions were induced mechanically, and a free epididymal fat graft from wild type or CAG-DsRed mice was injected preperitoneally immediately after adhesion induction. PET/CT imaging and scaling of the adhesions were performed, and samples were taken for further analysis at 7 and 30 days postoperation. Macrophage phenotyping was further performed from peritoneal lavage samples, and the expression of inflammatory cytokines and mesothelial layer recovery were analysed from peritoneal tissue samples. RESULTS: Fat grafting significantly inhibited the formation of adhesions. PET/CT results did not show prolonged inflammation in any of the groups. While the expression of anti-inflammatory and anti-fibrotic IL-10 was significantly increased in the peritoneum of the fat graft-treated group at 7 days, tissue-resident and repairing M2 macrophages could no longer be detected in the fat graft at this time point. The percentage of the continuous, healed peritoneum as shown by Keratin 8 staining was greater in the fat graft-treated group after 7 days. CONCLUSIONS: Fat grafting can inhibit the formation of peritoneal adhesions in mice. Our results suggest that fat grafting promotes the peritoneal healing process in a paracrine manner thereby enabling rapid regeneration of the peritoneal mesothelial cell layer.

Combined Surgical Treatment for Chronic Upper Extremity Lymphedema Patients: Simultaneous Lymph Node Transfer and Liposuction.

BACKGROUND: Upper limb lymphedema is a common problem after axillary lymph node dissection. Lymphatic drainage can be improved by microvascular lymph node transfer, whereas liposuction can be used to reduce arm volume and excess of adipose tissue. We present the results of chronic lymphedema patients who have undergone lymph node transfer and liposuction simultaneously in 1 operation and compare the results with patients who have undergone lymph node transfer without liposuction. METHODS: During May 2007 to February 2015, 20 postmastectomy patients and 1 Hodgkin's lymphoma patient presenting with chronic nonpitting lymphedema (age between 37 and 74 years, average 56.7 years) were operated using the combined technique and 27 postmastectomy patients presenting with early-stage lymphedema (age between 31 and 68 years, average age 50.2 years) were operated using only the lymph node transfer. Compression therapy was started immediately after the operation and the patients used compression 24 h/d at least 6 months postoperatively. Changes in clinical parameters (number of erysipelas infections, pain), arm volume, transport indexes calculated form lymphoscintigraphy images, and daily usage of compression garments were compared preoperatively and postoperatively and between groups (combined technique vs lymph node transfer). The study was a retrospective observational study. RESULTS: In the combined technique group, the average arm volume excess decreased postoperatively 87.7%, and in 7 of 10 patients, the edema volume did not increase even without compression. Seventeen of 21 patients were able to reduce the use of compression garment. Lymphoscintigraphy results were improved in 12 of 15 patients and the improvement was significantly greater in the combined technique group than in the lymph node transfer group (P = 0.01). The number of erysipelas infections was decreased in 7 of 10 patients and the decrease was significantly greater in the combined technique group than in the lymph node transfer group (P = 0.02). In the lymph node transfer group, the average excess volume decreased postoperatively 27.5%. Fourteen of 27 patients were able to reduce the use of compression garments. Lymphoscintigraphy results were improved in 8 of 19 patients, and the number of erysipelas infections was decreased in 1 of 3 patients. CONCLUSIONS: Liposuction can safely be performed with lymph node transfer in 1 operation to achieve optimal results in patients with chronic lymphedema. The combined technique provides immediate volume reduction and further regenerative effects on the lymphatic circulation. The significantly greater reduction in lymphoscintigraphy values and erysipelas infections suggests that the combined technique might be better for late-stage lymphedema patients than lymph node transfer alone.

Fat Grafting Can Induce Browning of White Adipose Tissue.

BACKGROUND: Fat grafting is commonly used when treating soft-tissue defects. However, much of the basic biology behind fat transfer is still uncovered. Adipocytes can be divided into energy storing white and energy burning brown adipose cells. It is now well known, that also adult humans have metabolically active brown adipose tissue (BAT) within white adipose tissue (WAT). Previously our group showed that transfer of metabolically inactive WAT into a new environment increased the metabolic activity of the fat grafts to resemble the activity in the recipient site and that different WAT depots have variation in the metabolic activity. This led us to speculate, whether the metabolic increase of the graft is a result of "browning" of the transferred WAT toward beige adipose tissue. METHODS: We investigated the metabolic and histological characteristics and BAT marker Ucp1 gene expression in different types of WAT grafts placed either in subcutaneous or muscle tissue in mice. Metabolic activity of the grafts was investigated by FDG-PET/CT at 4- and 12-week time-points. RESULTS: The glucose uptake of all transferred fat types was increased when compared with respective control WAT regardless of transfer location. Ucp1 gene and protein expression was increased in 4 of 15 intramuscularly placed fat graft samples and showed histological resemblance to BAT with multilocular cells. CONCLUSIONS: Grafting of metabolically inactive fat intramuscularly may induce browning of fat grafts toward more active beige adipose tissue. This opens up new research areas in exploiting fat grafting in metabolic diseases.

Lymphangiogenesis and Lymphangiogenic Growth Factors.

Lymphedema is a progressive disease caused by damage to the lymphatic network. Recent development in the fields of preclinical growth factor research and lymphedema microsurgery promise new hope for lymphedema patients. In this article, we review the latest results on basic research and highlight the role of specific growth factors in normal lymphatic development and several disease states. Lymph node transfer, a new promising method in reconstructive lymphatic microsurgery, is also dependent on the lymphatic vascular regrowth and lymphangiogenic growth factors. We discuss the scientific basis of lymph node transfer and therapeutic potential of lymphangiogenic growth factors in the treatment of lymphedema.

Anti-inflammatory effects of flap and lymph node transfer.

BACKGROUND: Transfer of healthy tissue is commonly used in the treatment of complicated wounds and in reconstruction of tissue defects. Recently, microvascular lymph node transfer (LN) has been used to improve the lymphatic function in lymphedema patients. To elucidate the biological effects of flap transfer (with and without lymph nodes), we have studied the postoperative production of proinflammatory, anti-inflammatory, prolymphangiogenic and antilymphangiogenic cytokines, and growth factors (interleukin 1α [IL-1α], IL-1ß, tumor necrosis factor α [TNF-α], IL-10, transforming growth factor ß1 [TGF-ß1], IL-4 and IL-13, and vascular endothelial growth factor C [VEGF-C] and VEGF-D) in postoperative wound exudate samples. METHODS: Axillary wound exudate samples were analyzed from four patient groups: axillary lymph node dissection (ALND), microvascular breast reconstruction (BR), LN, and combined LN and BR (LN-BR). RESULTS: The concentration of proinflammatory cytokines was low in all the flap transfer groups as opposed to the ALND group, which showed an extensive proinflammatory response. The level of anti-inflammatory and antifibrotic cytokine IL-10 was increased in the LN-BR group samples compared with the ALND and BR groups. In the LN and LN-BR groups, the cytokine profile showed an anti-inflammatory response. CONCLUSIONS: Transfer of healthy tissue hinders the proinflammatory response after surgery, which may explain the beneficial effects of flap transfer in various patient groups. In addition, flap transfer with lymph nodes seems to also promote an antifibrotic effect. The clinical effects of LN in lymphedema patients may be mediated by the increased production of prolymphangiogenic growth factor (VEGF-C) and antifibrotic cytokine (IL-10).

VEGF-C and VEGF-C156S in the pro-lymphangiogenic growth factor therapy of lymphedema: a large animal study.

INTRODUCTION: VEGF-C156S, a lymphangiogenesis-specific form of vascular endothelial growth factor C (VEGF-C), has been considered as a promising candidate for the experimental pro-lymphangiogenic treatment, as it lacks potential angiogenic effects. As a precursor to future clinical trials, the therapeutic efficacy and blood vascular side effects of VEGF-C and VEGF-C156S were compared in a large animal model of secondary lymphedema. Combination of lymphatic growth factor treatment and autologous lymph node transfer was used to normalize the lymphatic anatomy after surgical excision of lymphatic tissue. METHODS: Lymph vessels around the inguinal lymph node of female domestic pigs were destroyed in order to impair the normal lymphatic drainage from the hind limb. Local injections of adenoviruses (Ad) encoding VEGF-C or VEGF-C156S were used to enhance the regrowth of the lymphatic vasculature. AdLacZ (ß-galactosidase) and saline injections served as controls. RESULTS: Both VEGF-C and VEGF-C156S induced growth of new lymphatic vessels in the area of excision, although lymphangiogenesis was notably stronger after VEGF-C treatment. Also the transferred lymph nodes were best-preserved in the VEGF-C-treated pigs. Despite the enlargement of blood vessels following the VEGF-C therapy, no signs of sprouting angiogenesis or increased blood vascular permeability in the form of increased wound exudate volumes were observed. CONCLUSIONS: Our results show that VEGF-C provides the preferred alternative for growth factor therapy of lymphedema when compared to VEGF-C156S, due to the superior lymphangiogenic response and minor blood vessel effects. Furthermore, these observations suggest that activation of both VEGFR-2 and VEGFR-3 might be needed for efficient lymphangiogenesis.

Growth factor therapy and lymph node graft for lymphedema.

BACKGROUND: Lymphedema still remains an unsolved problem. Secondary lymphedema often develops after cancer operations or radiation therapy, especially in breast cancer patients. Using a mouse model, we show here that the lymphatic network can be regenerated using lymphatic vascular growth factor therapy in combination with lymph node transfer. MATERIALS AND METHODS: We have compared the therapeutic effects of different vascular endothelial growth factors (VEGF-C, VEGF-D, VEGF-C156S, and VEGF-A), in combination with lymph node transfer in mouse axilla. The lymphangiogenic effects of the growth factor therapy were examined at 3 mo postoperatively. RESULTS: VEGF therapy with VEGF-C and VEGF-D induced growth of new lymphatic vessels in the defect area, and VEGF-C also improved lymphatic vessel function compared with that of controls. VEGF-C156S induced moderate lymphangiogenesis, but the effect remained statistically nonsignificant. Prolymphangiogenic growth factors (VEGF-C, -D, and -C156S) also improved lymph node survival as compared with those of the VEGF-A and control group. VEGF-C, which activates both vascular endothelial growth factor receptor 2 and vascular endothelial growth factor receptor 3, gave the best therapeutic effect in this experimental lymphedema model. CONCLUSIONS: These results support our goal to treat secondary lymphedema by combining lymph node transfer with the growth factor therapy. VEGF-C provides the preferred alternative for growth factor therapy of lymphedema when compared with other VEGF-family growth factors, due to the superior lymphangiogenic response and minor blood vascular effects.

[Lymphedema]. / Lymfaturvotus.

Chronic swelling due to lymphatic insufficiency (lymphedema) is a common problem after surgical operations, radiation therapy, injuries and infections. Overweight is a new but rapidly increasing component of lymphedema. Treatment of lymphedema is based on compression therapy, lymph therapy and physiotherapy as well as various surgical treatment alternatives. Curative treatment has not been available. Over the last few years new imaging methods, surgical techniques and Finnish basic research have provided new tools for diagnostics and therapy.

Analysis of fat graft metabolic adaptation and vascularization using positron emission tomography-computed tomographic imaging.

BACKGROUND: Fat tissue transfer is commonly used for different soft-tissue defects in surgery. The immediate result of these operations is often good, but the long-term result is unfortunately unpredictable. The authors used an experimental model to evaluate the vascularization, survival, and metabolic changes after free fat transfer and the impact of proangiogenic therapy on these processes. METHODS: Fat was collected from the mouse epididymal region and placed into the subcutaneous tissue of the forehead. Fat grafts were treated with proangiogenic vascular endothelial growth factor (VEGF)-A (n = 9) or the control vector (n = 9). Metabolic activity and fat graft volume were investigated by positron emission tomography-computed tomography at 4 weeks and at 12 weeks. Histologic analysis was performed at 12 weeks. RESULTS: The glucose metabolism (fluorodeoxyglucose uptake) of the transferred epididymal fat was higher than in the epididymal fat before transplantation in both study groups (VEGF-A and control) and resembled that of normal subcutaneous fat. VEGF-A therapy enhanced the survival and capillary density of the transferred fat after surgery. CONCLUSIONS: Transfer of the metabolically inactive (epididymal) fat into a new environment modulated the metabolic activity of the fat grafts to resemble the situation in the recipient site. These novel findings support the clinical use of free fat grafts in various anatomical regions and tissue types. Proangiogenic VEGF-A therapy enhanced the vascularization and survival of the free fat grafts.

Lymphatic vessel function and lymphatic growth factor secretion after microvascular lymph node transfer in lymphedema patients.

BACKGROUND: Recent reports have shown that microvascular lymph node transfer may improve lymphatic drainage in lymphedema patients. Lymphatic anastomoses are expected to form spontaneously in response to lymphatic growth factor [vascular endothelial growth factor C (VEGF-C)] secreted by the transferred lymph nodes. METHODS: We have analyzed the results of 19 lymph node transfer patients operated on 2007-2012. Postoperat ive lymphatic function of the affected arm was evaluated using semiquantitative lymphoscintigraphy (transport index) and limb circumference measurements. To investigate the postoperative VEGF-C secretion, we examined axillary seroma fluid samples after different surgical operations, including lymph node transfer. RESULTS: The transport index was improved postoperatively in 7 of 19 patients. Ten of the 19 patients were able to reduce or even discontinue using compression garments. Arm circumferences were reduced in 12 of 19 patients. Six of the 7 patients with preoperative erysipelas infections have not had infectious episodes postoperatively during 15-67 months follow-up. Neuropathic pain was relieved in 5 of 5 patients. VEGF-C protein was detected in the axillary seroma fluid both after lymph node transfer and normal breast reconstruction. CONCLUSIONS: Reconstructing the lymphatic anatomy of the axilla with a lymph node flap may offer possibilities that other reconstructive options are lacking. However, we will need further reports and comparative studies about the clinical efficacy of this new promising technique. In addition to the transferred lymph nodes, lymphatic growth factor production may also be induced by other factors related to microvascular breast reconstruction.