Molecular analysis and differentiation capacity of adipose-derived stem cells from lymphedema tissue

Changes in intracellular water volume after leg lymphedema onset and lymphaticovenular anastomosis as its surgical intervention

OBJECTIVE

To clarify the changes in the intracellular water (ICW) volume in lymphedema-affected legs after lymphedema onset and its surgical intervention (ie, lymphaticovenular anastomosis [LVA]), we investigated the changes in body water composition using bioelectrical impedance analysis.

METHODS

This retrospective case series included 41 women with unilateral secondary leg lymphedema. The volume changes in the ICW and extracellular water (ECW) of the affected leg were measured using an InBody S10 (InBody Co, Ltd) multifrequency bioelectrical impedance analyzer, at both lymphedema onset and 1 year after LVA.

RESULTS

The volume increase with leg lymphedema onset was comparable between the ECW and ICW (0.59 L vs 0.56 L; 95% confidence interval [CI], -0.02 to 0.06; P = .27), and the increase rate was higher for ECW (35.3% vs 22.1%; 95% CI, 9.3%-17.2%; P < .001). The volume reduction at 1 year after LVA was comparable between ECW and ICW (0.23 L vs 0.27 L; 95% CI, -0.08 to 0.02; P = .20), and the reduction rate was higher for ECW (8.7% vs 7.0%, 95% CI, 0.04%-3.2%; P = .044). The volume difference between ICW and ECW remained constant throughout the six measurements before and after LVA (F[3.01, 120.20] = 1.85; P < .14).

CONCLUSIONS

Leg LVA reduced ICW in the lymphedematous leg. The onset of leg lymphedema increased ECW and ICW in the affected limb, and LVA decreased both ECW and ICW. The volume change in the affected leg was comparable between ECW and ICW at both lymphedema onset and after LVA. However, the rate of change was higher for ECW. The volume difference between ICW and ECW remained constant. Using bioelectrical impedance analysis, alterations in ICW volume were detected in the legs affected by lymphedema, both after the onset of lymphedema and after LVA intervention.

Thyroid Hormone Ameliorates Lymphedema by Suppressing Adipogenesis in a Murine Lymphedema Model

Background: Exogenous supplementation of thyroid hormone could inhibit excessive fat deposition in lymphedema tissue by suppressing adipogenesis. Methods and Results: Cell viability, adipogenic differentiation, and mRNA expression were measured in 3T3-L1 preadipocytes treated with L-thyroxine. Twelve mice were divided into control and L-thyroxine groups. Two weeks after lymphedema was surgically induced, the experimental mice were fed L-thyroxine for 4 weeks. Tail volume and body weight were measured, and 6 weeks after the surgery, tail skin and subcutaneous tissue were harvested for histopathologic examination and protein isolation. In 3T3-L1 cells, treatment with 10-500 μM L-thyroxine did not affect cell viability. Eight days after induction of adipogenic differentiation, lipid accumulation decreased significantly in the 50 and 100 μM L-thyroxine groups (p < 0.001). mRNA levels of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and fatty acid-binding protein 4 (FABP4) decreased significantly in the 100 μM L-thyroxine group compared with the control group (p = 0.017). Lymphedema tails treated with L-thyroxine exhibited decreased volume (p = 0.028) and thickness of dermal and subcutaneous tissue (p = 0.01) and increased vascular endothelial growth factor-C protein expression (p = 0.017) compared with the control. Conclusion: Thyroid hormone therapy inhibits the adipogenesis of 3T3-L1 cells in vitro and decreases the volume of murine lymphedema tail in vivo. These findings suggest that thyroid hormone therapy could be used to treat lymphedema.

Application of adipose-derived mesenchymal stem cells in an in vivo model of peripheral nerve damage

Background

Neuropathic pain is one of the most difficult to treat chronic pain syndromes. It has significant effects on patients’ quality of life and substantially adds to the burden of direct and indirect medical costs. There is a critical need to improve therapies for peripheral nerve regeneration. The aim of this study is to address this issue by performing a detailed analysis of the therapeutic benefits of two treatment options: adipose tissue derived-mesenchymal stem cells (ASCs) and ASC-conditioned medium (CM).

Methods

To this end, we used an in vivo rat sciatic nerve damage model to investigate the molecular mechanisms involved in the myelinating capacity of ASCs and CM. Furthermore, effect of TNF and CM on Schwann cells (SCs) was evaluated. For our in vivo model, biomaterial surgical implants containing TNF were used to induce peripheral neuropathy in rats. Damaged nerves were also treated with either ASCs or CM and molecular methods were used to collect evidence of nerve regeneration. Post-operatively, rats were subjected to walking track analysis and their sciatic functional index was evaluated. Morphological data was gathered through transmission electron microscopy (TEM) of sciatic nerves harvested from the experimental rats. We also evaluated the effect of TNF on Schwann cells (SCs) in vitro. Genes and their correspondent proteins associated with nerve regeneration were analyzed by qPCR, western blot, and confocal microscopy.

Results

Our data suggests that both ASCs and CM are potentially beneficial treatments for promoting myelination and axonal regeneration. After TNF-induced nerve damage we observed an upregulation of c-Jun along with a downregulation of Krox-20 myelin-associated transcription factor. However, when CM was added to TNF-treated nerves the opposite effect occurred and also resulted in increased expression of myelin-related genes and their corresponding proteins.

Conclusion

Findings from our in vivo model showed that both ASCs and CM aided the regeneration of axonal myelin sheaths and the remodeling of peripheral nerve morphology.

Single-cell RNA sequencing of subcutaneous adipose tissues identifies therapeutic targets for cancer-associated lymphedema

Cancer-associated lymphedema frequently occurs following lymph node resection for cancer treatment. However, we still lack effective targeted medical therapies for the treatment or prevention of this complication. An in-depth elucidation of the cellular alterations in subcutaneous adipose tissues of lymphedema is essential for medical development. We performed single-cell RNA sequencing of 70,209 cells of the stromal vascular fraction of adipose tissues from lymphedema patients and healthy donors. Four subpopulations of adipose-derived stromal cells (ASCs) were identified. Among them, the PRG4⁺/CLEC3B⁺ ASC subpopulation c3 was significantly expanded in lymphedema and related to adipose tissue fibrosis. Knockdown of CLEC3B in vitro could significantly attenuate the fibrogenesis of ASCs from patients. Adipose tissues of lymphedema displayed a striking depletion of LYVE⁺ anti-inflammatory macrophages and exhibited a pro-inflammatory microenvironment. Pharmacological blockage of Trem1, an immune receptor predominantly expressed by the pro-inflammatory macrophages, using murine LR12, a dodecapeptide, could significantly alleviate lymphedema in a mouse tail model. Cell–cell communication analysis uncovered a perivascular ligand-receptor interaction module among ASCs, macrophages, and vascular endothelial cells. We provided a comprehensive analysis of the lineage–specific changes in the adipose tissues from lymphedema patients at a single-cell resolution. CLEC3B was found to be a potential target for alleviating adipose tissue fibrosis. Pharmacological blockage of TREM1 using LR12 could serve as a promising medical therapy for treating lymphedema.

Liposuction and Controlled Compression Therapy Reduce the Erysipelas Incidence in Primary and Secondary Lymphedema

BACKGROUND

Skin infections are a recurring problem for people with lymphedema, and lymphedema has been proven to be the single most important risk factor for developing erysipelas in the leg. This study aimed to determine whether liposuction for late-stage lymphedema reduces the rate of erysipelas in lower extremity lymphedema.

METHODS

One-hundred twenty-four patients with a median age of 49 years who had liposuction and controlled compression therapy for lower extremity lymphedema were included. Excess volumes were calculated before and after surgery. Median preoperative and postoperative patient years at risk were 11 and 5 years, respectively.

RESULTS

With a total of 1680 preoperative person years at risk and 335 bouts of erysipelas experienced in 64 patients, the preoperative incidence rate was 0.20 bouts per person per year, and the period prevalence was 52%. Postoperatively, the patients were followed over a total of 763 person years at risk, and 28 patients experienced a total of 53 bouts of erysipelas, resulting in a postoperative incidence rate of 0.07 bouts per person per year, and a period prevalence of 23%. This represents a 65% decrease in the erysipelas incidence rate (P < 0.001). The preoperative median excess volume of 3158 ml was reduced with a median of 100% (P < 0.0001).

CONCLUSIONS

Liposuction and controlled compression therapy significantly reduce the risk for erysipelas in lower extremity lymphedema and completely reduces the excess volume. This finding is similar to our previous research including patients with upper extremity lymphedema.

Crosstalk Between Adipose and Lymphatics in Health and Disease

Adipose tissue, once thought to be an inert receptacle for energy storage, is now recognized as a complex tissue with multiple resident cell populations that actively collaborate in response to diverse local and systemic metabolic, thermal, and inflammatory signals. A key participant in adipose tissue homeostasis that has only recently captured broad scientific attention is the lymphatic vasculature. The lymphatic system's role in lipid trafficking and mediating inflammation makes it a natural partner in regulating adipose tissue, and evidence supporting a bidirectional relationship between lymphatics and adipose tissue has accumulated in recent years. Obesity is now understood to impair lymphatic function, whereas altered lymphatic function results in aberrant adipose tissue deposition, though the molecular mechanisms governing these phenomena have yet to be fully elucidated. We will review our current understanding of the relationship between adipose tissue and the lymphatic system here, focusing on known mechanisms of lymphatic-adipose crosstalk.

Lymphedema alters lipolytic, lipogenic, immune and angiogenic properties of adipose tissue: a hypothesis-generating study in breast cancer survivors

Later stages of secondary lymphedema are associated with the massive deposition of adipose tissue (AT). The factors driving lymphedema-associated AT (LAT) expansion in humans remain rather elusive. We hypothesized that LAT expansion could be based on alterations of metabolic, adipogenic, immune and/or angiogenic qualities of AT. AT samples were acquired from upper limbs of 11 women with unilateral breast cancer-related lymphedema and 11 healthy women without lymphedema. Additional control group of 11 female breast cancer survivors without lymphedema was used to assess systemic effects of lymphedema. AT was analysed for adipocyte size, lipolysis, angiogenesis, secretion of cytokines, immune and stem cell content and mRNA gene expression. Further, adipose precursors were isolated and tested for their proliferative and adipogenic capacity. The effect of undrained LAT- derived fluid on adipogenesis was also examined. Lymphedema did not have apparent systemic effect on metabolism and cytokine levels, but it was linked with higher lymphocyte numbers and altered levels of several miRNAs in blood. LAT showed higher basal lipolysis, (lymph)angiogenic capacity and secretion of inflammatory cytokines when compared to healthy AT. LAT contained more activated CD4+ T lymphocytes than healthy AT. mRNA levels of (lymph)angiogenic markers were deregulated in LAT and correlated with markers of lipolysis. In vitro, adipose cells derived from LAT did not differ in their proliferative, adipogenic, lipogenic and lipolytic potential from cells derived from healthy AT. Nevertheless, exposition of preadipocytes to LAT-derived fluid improved their adipogenic conversion when compared with the effect of serum. This study presents results of first complex analysis of LAT from upper limb of breast cancer survivors. Identified LAT alterations indicate a possible link between (lymph)angiogenesis and lipolysis. In addition, our in vitro results imply that AT expansion in lymphedema could be driven partially by exposition of adipose precursors to undrained LAT-derived fluid.

Wnt Signaling Regulates the Lymphatic Endothelial Transdifferentiation of Adipose-Derived Stromal Cells In Vitro

Lymphedema is a chronic, progressive disease that causes pain as well as heavy economic burdens to patients. Reconstruction of the impaired lymphatic system is the key to treat lymphedema. Currently, there is no cure, but mesenchymal stromal cells show promising potential for lymphatic endothelial regeneration. Adipose-derived stromal cells (ADSCs) have been proved to support lymphangiogenesis both in vivo and in vitro. However, the mechanism in vascular endothelial growth factor C-induced (VEGF-C-induced) lymphatic endothelial transdifferentiation of ADSCs remains unknown. In this study, we show a novel link between the Wingless and int-1 (Wnt) pathway and the lymphatic endothelial differentiation process. We used LiCl to activate Wnt and DKK-1 to inhibit Wnt. Compared with the Wnt inhibition group and the control groups, the Wnt activation group produced more lymphatic endothelial cell (LEC)-related mRNA and proteins. Besides, Wnt-activated ADSCs formed longer tubes in two-dimensional culture and promoted the growth of lymphatic vessels in a three-dimensional transwell ADSC-LEC co-culture system. Our results demonstrated that activation of Wnt during the lymphatic endothelial transdifferentiation of ADSCs would enhance the efficacy of VEGF-C treatment. We anticipate our assay to expand our knowledge of Wnt in cell transdifferentiation and lay a foundation for future efforts to explore a novel and effective ADSC-based therapy for lymphedema.

Therapeutic Potential of Mesenchymal Stem Cells for Postmastectomy Lymphedema: A Literature Review

Upper limb lymphedema is one of the most common complications after breast cancer surgery and radiotherapy. Despite various physical therapy and surgical options available, the impaired lymph fluid drainage may be progressive due to lymphatic vascular insufficiency making treatment more difficulty. Stem cell therapy provides a promising alternative in the treatment of various chronic diseases. The wide applicability of cell therapy has been reviewed throughout literature. This review provides an overview of recent progress in the therapeutic effect of adult stem cells for primary and secondary lymphedema after breast surgery in preclinical studies and clinical cases. We start with a brief introduction about the pathophysiological mechanisms of postmastectomy lymphedema. Regarding existing treatments, we systematically summarize the benefits and limitations of recent progress. Because of their multidirectional differentiation potential and growth factor secretion, stem cell therapy shows promising results in the management of light to severe lymphedema. Increasing evidences have demonstrated a noticeable reduction in postmastectomy lymphedema and increased lymph-angiogenesis after specific stem cell therapy. Current data suggests that stem cell therapy in lymphedema treatment provides reversal of pathological reorganization associated with lymphedema progression. Finally, we propose potential strategies for overcoming the challenges in the development of multipotent progenitor cells for the treatment and prevention of lymphedema in clinical practice.

In Vitro Cultures of Adipose-Derived Stem Cells: An Overview of Methods, Molecular Analyses, and Clinical Applications

Adipose-derived stem cells (ASCs) exhibiting mesenchymal stem cell (MSC) characteristics, have been extensively studied in recent years. Because they have been shown to differentiate into lineages such as osteogenic, chondrogenic, neurogenic or myogenic, the focus of most of the current research concerns either their potential to replace bone marrow as a readily available and abundant source of MSCs, or to employ them in regenerative and reconstructive medicine. There is close to consensus regarding the methodology used for ASC isolation and culture, whereas a number of molecular analyses implicates them in potential therapies of a number of pathologies. When it comes to clinical application, there is a range of examples of animal trials and clinical studies employing ASCs, further emphasizing the advancement of studies leading to their more widespread use. Nevertheless, in vitro studies will most likely continue to play a significant role in ASC studies, both providing the molecular knowledge of their ex vivo properties and possibly serving as an important step in purification and application of those cells in a clinical setting. Therefore, it is important to consider current methods of ASC isolation, culture, and processing. Furthermore, molecular analyses and cell surface properties of ASCs are essential for animal studies, clinical studies, and therapeutic applications of the MSC properties.

The Release of Adipose Stromal Cells from Subcutaneous Adipose Tissue Regulates Ectopic Intramuscular Adipocyte Deposition

Ectopic lipid deposition (ELD) is defined by excess fat storage in locations not classically associated with adipose tissue (AT) storage. ELD is positively correlated with insulin resistance and increased risk of metabolic disorders. ELD appears as lipid droplets or adipocytes, whose cell origin is unknown. We previously showed that subcutaneous AT (ScAT) releases adipocyte progenitors into the circulation. Here, we demonstrate that triggering or preventing the release of adipocyte precursors from ScAT directly promoted or limited ectopic adipocyte formation in skeletal muscle in mice. Importantly, obesity-associated metabolic disorders could be mimicked by causing adipocyte precursor release without a high-fat diet. Finally, during nutrient overload, adipocyte progenitors exited ScAT, where their retention signals (CXCR4/CXCL12 axis) were greatly decreased, and further infiltrated skeletal muscles. These data provide insights into the formation of ELD associated with calorie overload and highlight adipocyte progenitor trafficking as a potential target in the treatment of metabolic diseases.

A comparison of the use of adipose-derived and bone marrow-derived stem cells for peripheral nerve regeneration in vitro and in vivo

Background

To date, it has repeatedly been demonstrated that infusing bone marrow-derived stem cells (BMSCs) into acellular nerve scaffolds can promote and support axon regeneration through a peripheral nerve defect. However, harvesting BMSCs is an invasive and painful process fraught with a low cellular yield.

Methods

In pursuit of alternative stem cell sources, we isolated stem cells from the inguinal subcutaneous adipose tissue of adult Sprague–Dawley rats (adipose-derived stem cells, ADSCs). We used a co-culture system that allows isolated adult mesenchymal stem cells (MSCs) and Schwann cells (SCs) to grow in the same culture medium but without direct cellular contact. We verified SC phenotype in vitro by cell marker analysis and used red fluorescent protein-tagged ADSCs to detect their fate after being injected into a chemically extracted acellular nerve allograft (CEANA). To compare the regenerative effects of CEANA containing either BMSCs or ADSCs with an autograft and CEANA only on the sciatic nerve defect in vivo, we performed histological and functional assessments up to 16 weeks after grafting.

Results

In vitro, we observed reciprocal beneficial effects of ADSCs and SCs in the ADSC–SC co-culture system. Moreover, ADSCs were able to survive in CEANA for 5 days after in vitro implantation. Sixteen weeks after grafting, all results consistently showed that CEANA infused with BMSCs or ADSCs enhanced injured sciatic nerve repair compared to the acellular CEANA-only treatment. Furthermore, their beneficial effects on sciatic injury regeneration were comparable as histological and functional parameters evaluated showed no statistically significant differences. However, the autograft group was roundly superior to both the BMSC- or ADSC-loaded CEANA groups.

Conclusion

The results of the present study show that ADSCs are a viable alternative stem cell source for treating sciatic nerve injury in lieu of BMSCs.

Transcriptome analysis and functional identification of adipose-derived mesenchymal stem cells in secondary lymphedema

Background

Secondary lymphedema is a common condition that affects patients with malignant tumors. Conservative treatments fail to provide lasting relief because they do not address the underlying pathological accumulation of excessive fat. Our aim is to clarify the molecular mechanisms of abnormal adipogenic differentiation in lymphedema adipose tissue.

Methods

We compared the proliferation and adipogenesis potential of adipose-derived mesenchymal stem cells (ASCs) from the lymphedema adipose tissue from liposuction specimens of 10 patients with extremity lymphedema with that of ASCs from adipose tissue from the normal upper abdomen of the same patients. Transcriptome analysis were performed to identify the differences between the two kinds of ASCs. Cyclin-dependent kinase 1 (CDK1) inhibitors were used to treat the abnormal ASCs in lymphedema adipose tissue.

Results

Our results demonstrate that significant functional and transcriptomic differences exist between the two kinds of ASCs. Up-regulated genes were mainly involved in cell proliferation and division while down-regulated genes were mainly associated with immune responses and inflammatory as well as osteogenic and myogenic differentiation. Furthermore, we find that the excessive proliferation and adipogenesis of ASCs from lymphedema adipose tissue returned to the normal phenotype by CDK1 inhibitors. ASCs from lymphedema adipose tissues have higher immunosuppressive effect and the cytokines related to immunosuppressive was significantly up-regulated.

Conclusions

In conclusion, lymphedema-associated ASCs had more rapid proliferation and a higher adipogenic differentiation capacity. CDK1 may be a key driver of proliferation and adipogenic differentiation in these cells, which might expound the accumulation of adipose tissue extensively observed in secondary lymphedema. ASCs from lymphedema adipose tissues showed immunomodulation dysfunction and immunomodulation may play an important role in the pathogenesis of lymphedema.

Lymphatic Vasculature in Energy Homeostasis and Obesity

Obesity is a leading cause of cardiovascular diseases and cancer. Body mass is regulated by the balance between energy uptake and energy expenditure. The etiology of obesity is determined by multiple factors including genetics, nutrient absorption, and inflammation. Lymphatic vasculature is starting to be appreciated as a critical modulator of metabolism and obesity. The primary function of lymphatic vasculature is to maintain interstitial fluid homeostasis. Lymphatic vessels absorb fluids that extravasate from blood vessels and return them to blood circulation. In addition, lymphatic vessels absorb digested lipids from the intestine and regulate inflammation. Hence, lymphatic vessels could be an exciting target for treating obesity. In this article, we will review our current understanding regarding the relationship between lymphatic vasculature and obesity, and highlight some open questions.

Adipose-Derived Stem Cells and Ceiling Culture-Derived Preadipocytes Cultured from Subcutaneous Fat Tissue Differ in Their Epigenetic Characteristics and Osteogenic Potential

BACKGROUND

Adipose-derived stem cells and ceiling culture-derived preadipocytes can be harvested from subcutaneous adipose tissue. Little is known about the epigenetic differences, which may contribute to differences in osteogenic potential, between these cell types. The purpose of this study was to address the osteogenic potential and underlying epigenetic status of adipose-derived stem cells and ceiling culture-derived preadipocytes.

METHODS

Adipose-derived stem cells and ceiling culture-derived preadipocytes were cultured from abdominal subcutaneous fat tissues of four metabolically healthy, lean female patients. After 7 weeks of culture, cellular responses to osteogenic differentiation media were examined. To evaluate the osteogenic potentials of undifferentiated adipose-derived stem cells and ceiling culture-derived preadipocytes, two types of epigenetic assessment were performed using next-generation sequencing: DNA methylation assays with the Human Methylation 450K BeadChip, and chromatin immunoprecipitation assays for trimethylation of histone H3 at lysine 4.

RESULTS

Human ceiling culture-derived preadipocytes showed greater osteogenic differentiation ability than did adipose-derived stem cells. In an epigenetic survey of the promoters of four osteogenic regulator genes (RUNX2, SP7, ATF4, and BGLAP), the authors found a general trend toward decreased CpG methylation and increased trimethylation of histone H3 at lysine 4 levels in ceiling culture-derived preadipocytes as compared to adipose-derived stem cells, indicating that these genes were more likely to be highly expressed in ceiling culture-derived preadipocytes.

CONCLUSIONS

The surveyed epigenetic differences between adipose-derived stem cells and ceiling culture-derived preadipocytes were consistent with the observed differences in osteogenic potential. These results enhance the authors' understanding of these cells and will facilitate their further application in regenerative medicine.

A vicious circle in chronic lymphoedema pathophysiology? An adipocentric view

Chronic lymphoedema is a disease caused by a congenital or acquired damage to the lymphatic system and characterized by complex chains of pathophysiologic events such as lymphatic fluid stasis, chronic inflammation, lymphatic vessels impairment, adipose tissue deposition and fibrosis. These events seem to maintain and reinforce themselves through a positive feedback loop: regardless of the initial cause of lymphatic stasis, the dysfunctional adipose tissue and its secretion products can worsen lymphatic vessels' function, aggravating lymph leakage and stagnation, which can promote further adipose tissue deposition and fibrosis, similar to what may happen in obesity. In addition to the current knowledge about the tight and ancestral interrelation between immunity system and metabolism, there is evidence for similarities between obesity-related and lymphatic damage-induced lymphoedema. Together, these observations indicate strong reciprocal relationship between lymphatics and adipose tissue and suggest a possible key role of the adipocyte in the pathophysiology of chronic lymphoedema's vicious circle.

Lymphedema Leads to Fat Deposition in Muscle and Decreased Muscle/Water Volume After Liposuction: A Magnetic Resonance Imaging Study

Background: Lymphedema leads to adipose tissue deposition. Water–fat magnetic resonance imaging (MRI) can quantify and localize fat and water. The presence of excess fat and excess water/muscle in the subfascial compartment of the lymphedematous limb has not been investigated before. The aim of this study was to investigate epifascial and subfascial fat and water contents in patients with chronic lymphedema before and after liposuction.

Methods and Results: Seven patients with arm lymphedema and six with leg lymphedema were operated on. The limbs were examined with water–fat MRI before liposuction (baseline) and at five time points. Complete reduction of the excess limb volumes was achieved. The excess epifascial fat was evident in the edematous limbs and a drop was seen following surgery. There were differences in excess water at all time points. At 1 year there was a decrease in excess water. Excess subfascial fat was seen in the edematous limbs at all time points. Subfascial excess water/muscle did not show any differences after surgery. However, starting from 3 months there was less subfascial water/muscle compared with baseline.

Conclusions: Subfascial fat in the lymphedematous limbs did not change. In contrast, the water in the subfascial compartment was reduced over time, which may represent a decrease of muscle volume after treatment due to less mechanical load after liposuction. Using water–fat MRI-based fat quantification, the fat and water contents may be quantified and localized in the various compartments in lymphedema.

Changes in arm tissue composition with slowly progressive weight-lifting among women with breast cancer-related lymphedema

BACKGROUND

Studies in breast cancer-related lymphedema (BRCL) have exclusively examined total arm volume, but not the specific tissue composition that contributes to total volume. We evaluated baseline differences in arm tissue composition [fat mass, lean mass, bone mineral content (BMC), and bone mineral density (BMD)] between the affected and unaffected arms in women with BRCL. We compared changes in arm tissue composition and self-reported lymphedema symptoms after 1 year of weight-lifting versus control.

METHODS

We utilized data from physical activity and lymphedema trial that included 141 women with BRCL. Arm tissue composition was quantified using dual-energy X-ray absorptiometry. The severity of lymphedema was quantified using self-report survey. Weight-lifting was performed at community fitness facilities.

RESULTS

At baseline, the affected arm had more fat (∆ = 89.7 g; P < 0.001) and lean mass (∆ = 149.1 g; P < 0.001), but less BMC (∆ = -3.2 g; P < 0.001) and less BMD (∆ = -5.5 mg/cm2; P = 0.04) than the unaffected arm. After 12 months of weight-lifting, composition of the affected arm was improved: lean mass (71.2 g; P = 0.01) and BMD (14.0 mg/cm2; P = 0.02) increased, arm fat percentage decreased (-1.5%; P = 0.003). Composition of the unaffected arm was only improved in lean mass (65.2 g; P = 0·04). Increases in lean mass were associated with less severe BCRL symptoms.

CONCLUSIONS

Among women with BRCL, slowly progressive weight-lifting could improve arm tissue composition. Changes in arm tissue composition predict changes in symptom burden. Investigating the combined effects of exercise and weight loss on arm tissue composition and BCRL symptoms may provide additional insight into the benefits of lifestyle modification on lymphedema biology.

Osteogenic Differentiation of MSC through Calcium Signaling Activation: Transcriptomics and Functional Analysis

The culture of progenitor mesenchymal stem cells (MSC) onto osteoconductive materials to induce a proper osteogenic differentiation and mineralized matrix regeneration represents a promising and widely diffused experimental approach for tissue-engineering (TE) applications in orthopaedics. Among modern biomaterials, calcium phosphates represent the best bone substitutes, due to their chemical features emulating the mineral phase of bone tissue. Although many studies on stem cells differentiation mechanisms have been performed involving calcium-based scaffolds, results often focus on highlighting production of in vitro bone matrix markers and in vivo tissue ingrowth, while information related to the biomolecular mechanisms involved in the early cellular calcium-mediated differentiation is not well elucidated yet. Genetic programs for osteogenesis have been just partially deciphered, and the description of the different molecules and pathways operative in these differentiations is far from complete, as well as the activity of calcium in this process. The present work aims to shed light on the involvement of extracellular calcium in MSC differentiation: a better understanding of the early stage osteogenic differentiation program of MSC seeded on calcium-based biomaterials is required in order to develop optimal strategies to promote osteogenesis through the use of new generation osteoconductive scaffolds. A wide spectrum of analysis has been performed on time-dependent series: gene expression profiles are obtained from samples (MSC seeded on calcium-based scaffolds), together with related microRNAs expression and in vivo functional validation. On this basis, and relying on literature knowledge, hypotheses are made on the biomolecular players activated by the biomaterial calcium-phosphate component. Interestingly, a key role of miR-138 was highlighted, whose inhibition markedly increases osteogenic differentiation in vitro and enhance ectopic bone formation in vivo. Moreover, there is evidence that Ca-P substrate triggers osteogenic differentiation through genes (SMAD and RAS family) that are typically regulated during dexamethasone (DEX) induced differentiation.

Higher vascular endothelial growth factor-C concentration in plasma is associated with increased forearm capillary filtration capacity in breast cancer-related lymphedema

Breast cancer-related lymphedema (BCRL) is a frequent, chronic and debilitating swelling that mainly affects the ipsilateral arm and develops as a complication to breast cancer treatment. The pathophysiology is elusive opposing development of means for prediction and treatment. We have earlier shown that the forearm capillary filtration coefficient (CFC) is increased bilaterally in BCRL. In this study, we aimed to elucidate if increased CFC is associated with low-grade inflammation and/or vascular endothelial growth factor-c (VEGF-C) signaling. Fourteen patients with unilateral BCRL and nine matched breast cancer controls without BCRL participated. Forearm CFC was measured by venous congestion strain gauge plethysmography, and suction blisters were induced medially on the upper arms. Concentrations of 17 selected cytokines, VEGF-C, and total protein were measured in blister fluid and in plasma. Forearm CFC was higher bilaterally in BCRL subjects (P ≤ 0.036). No differences between forearms were found in either group. Plasma VEGF-C concentrations were significantly higher in the BCRL subjects (P < 0.001). In BCRL subjects, monocyte chemotactic protein 1 (MCP-1) (P = 0.009) and total protein (P = 0.035) concentrations were higher in blister fluid from edematous arms compared with nonedematous arms. No differences were found in interstitial cytokine or total protein concentrations between arms in control subjects. Higher plasma concentration of VEGF-C is a possible cause of bilaterally increased forearm CFC in BCRL subjects. Interstitially increased MCP-1 levels may augment local microvascular protein permeability in BCRL.

Aging disrupts cell subpopulation dynamics and diminishes the function of mesenchymal stem cells

Advanced age is associated with an increased risk of vascular morbidity, attributable in part to impairments in new blood vessel formation. Mesenchymal stem cells (MSCs) have previously been shown to play an important role in neovascularization and deficiencies in these cells have been described in aged patients. Here we utilize single cell transcriptional analysis to determine the effect of aging on MSC population dynamics. We identify an age-related depletion of a subpopulation of MSCs characterized by a pro-vascular transcriptional profile. Supporting this finding, we demonstrate that aged MSCs are also significantly compromised in their ability to support vascular network formation in vitro and in vivo. Finally, aged MSCs are unable to rescue age-associated impairments in cutaneous wound healing. Taken together, these data suggest that age-related changes in MSC population dynamics result in impaired therapeutic potential of aged progenitor cells. These findings have critical implications for therapeutic cell source decisions (autologous versus allogeneic) and indicate the necessity of strategies to improve functionality of aged MSCs.

Lymphedema fat graft: an ideal filler for facial rejuvenation

Lymphedema is a chronic disorder characterized by lymph stasis in the subcutaneous tissue. Lymphatic fluid contains several components including hyaluronic acid and has many important properties. Over the past few years, significant research has been performed to identify an ideal tissue to implant as a filler. Because of its unique composition, fat harvested from the lymphedema tissue is an interesting topic for investigation and has significant potential for application as a filler, particularly in facial rejuvenation. Over a 36-month period, we treated and assessed 8 patients with lymphedematous limbs who concurrently underwent facial rejuvenation with lymphedema fat (LF). We conducted a pre- and post-operative satisfaction questionnaire survey and a histological assessment of the harvested LF fat. The overall mean general appearance score at an average of 6 months after the procedure was 7.2±0.5, demonstrating great improvement. Patients reported significant improvement in their skin texture with a reading of 8.5±0.7 and an improvement in their self-esteem. This study demonstrates that LF as an ideal autologous injectable filler is clinically applicable and easily available in patients with lymphedema. We recommend the further study and clinical use of this tissue as it exhibits important properties and qualities for future applications and research.

Adipose-derived stem cells: methods for isolation and applications for clinical use

Adipose tissue sciences have rapidly expanded since the identification of regenerative cells contained within the stromal vascular fraction (SVF) of fat. Isolation of the SVF, containing adipose-derived stem cells (ADSC), can be accomplished efficiently in the operating room or in the laboratory through enzymatic digestion of the adipose tissue and concentration of SVF. Cells can be directly re-injected as a mesotherapeutic agent, recombined with a tissue scaffold (e.g., cell-enriched fat grafts) or expanded in culture for tissue-engineered cell therapeutics. The potential for cell therapy is under current investigation by researchers around the world. This chapter reviews laboratory methods for isolating ADSCs and the ongoing clinical trials evaluating cell therapeutic efficacy across many specialties, including cardiology, neurology, immunology, tissue engineering, sports medicine, and plastic and reconstructive surgery.