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Background: Breast cancer is the most common cancer in women. Cancer cells can persist in a prolonged dormant state for years without any clinical evidence of disease creating an urgent need to better understand the molecular mechanisms leading to relapse. This study aimed to identify extracellular matrix (ECM) components associated with hypoxia-induced breast cancer dormancy. The effects of selected ECM proteins on breast cancer cell proliferation were analyzed, along with their correlation with established prognostic markers in human breast cancer tissue.

Materials and methods: Screening of extracellular matrix proteins was performed in hypoxia-induced dormant MCF-7 breast cancer cells. Proliferation of MCF-7 cells in vitro was subsequently determined in the presence of recombinant ColVII. Adipose tissue-derived mesenchymal stem cells (AdMSCs) subpopulation overexpressing ColVII were indirectly isolated by ColVII receptor integrin-α6 specific antibodies. AdMSCs- MCF-7 3D spheroid cultures were generated to model solid tumour conditions. In addition, the association between ColVII and various prognostic markers was evaluated in clinical samples of human breast cancer tissue.

Results: Dormant MCF-7 cells showed an elevated expression of ColVII while MCF-7 cells cultured on ColVII exhibited reduced proliferation in vitro. In AdMSCs-MCF-7 3D spheroids, a reduced proliferation of MCF-7 cells was observed in Int-α6+/ ColVIIhigh compared with Int-α6-/ ColVIIlow AdMSCs spheroids. In human tissue, high ColVII expression correlated to several positive prognostic markers. Staining for Cytokeratin-5 revealed that ColVIIhigh-expressing cells were predominantly myoepithelial cells.

Conclusion: ColVII is associated with reduced proliferation of breast cancer cells in vitro. ColVII is strongly expressed in myoepithelial cells and in breast cancer tissue the high ColVII expression correlates with several well-known positive prognostic markers, highlighting its potential as a prognostic marker in breast cancer.

Background: There are no published international consensus or guideline documents regarding appropriate medical follow-up for women with hereditary increased risk of breast cancer who opt for prophylactic mastectomy. Moreover, it is not known whether breast magnetic resonance imaging (MRI) performed after a prophylactic mastectomy is a reproducible method for evaluating whether clinically relevant amounts of residual glandular tissue remains.

Purpose: To evaluate the inter- and intra-observer agreement on detecting residual glandular tissue with MRI. Material and Methods: In total, 40 women previously operated with prophylactic mastectomy underwent MRI and two breast radiologists (R1 and R2) independently assessed the presence of residual glandular tissue. Inter- and intra-rater agreements were assessed using Cohen's kappa (k).

Results: Residual glandular tissue was found in 69 of 248 quadrants (27.8%) and 32 of 62 breasts (51.6%) by R1 and 77 of 248 quadrants (31.1%) and 35 of 62 breasts (56.5%) by R2. The interrater agreement was observed to be moderate (k = 0.554) and the intra-rater agreement was observed to be substantial (k = 0.623).

Conclusion: In conclusion, the inter-and intra-rater observer agreement in regard to detection of residual glandular tissue was not excellent, which would be desirable for a method considered reproducible enough to be used as a surveillance tool after the surgical procedure in order to ensure that there is no relevant residual glandular tissue remaining warranting further follow-up. More research is needed, as well as establishment of precise protocols, before using the method in risk assessment of remaining glandular tissue and breast cancer risk.

Background: Although autologous fat grafting is considered a successful method for the management of contour deformities, the fat graft could potentially induce cancer reappearance by fueling dormant breast cancer cells. Our aim was to characterize the role of adipose-derived stem cells on active and dormant breast cancer cell growth.

Methods: Cobalt chloride was used to induce dormancy in MCF-7 cancer cells. Proliferation of active and dormant cancer cells was determined in the presence of adipose-derived stem cells. A proteome array was used to detect cancer-related protein expression in the cell-conditioned medium. The migration of cancer cells was measured in response to conditioned medium from the adipose-derived stem cells.

Results: The adipose-derived stem cells showed variable effects on active MCF-7 cells growth and inhibited MCF-7 proliferation after the withdrawal of cobalt chloride. Of the 84 different proteins measured in the conditioned medium, only tenascin-C was differentially expressed in the co-cultures. MCF-7 cells alone did not express tenascin-C, whereas co-cultures between MCF-7 and adipose-derived stem cells expressed more tenascin-C versus adipose-derived stem cells alone. The conditioned medium from co-cultures significantly increased the migration of the cancer cells.

Conclusions: Adipose-derived stem cells themselves neither increased the growth or migration of cancer cells, suggesting that autologous fat grafting may be oncologically safe if reconstruction is postponed until there is no evidence of active disease. However, interactions between adipose-derived stem cells and MCF-7 cancer cells could potentially lead to the production of factors, which further promote cancer cell migration.

BACKGROUND: Soft tissue defects or periprosthetic infections after total knee arthroplasty (TKA) are severe complications that may lead to loss of the arthroplasty or the limb. Reconstructions with medial gastrocnemius flaps (MGF) are occasionally used to provide soft tissue coverage around the knee.

AIMS: The study aimed to establish the rate of implant survivorship after MGF reconstruction for soft tissue coverage in the treatment of exposed or infected TKA and to establish functional outcome.

METHODS: A retrospective analysis was performed on all patients who received soft tissue coverage with an MGF of an exposed or infected TKA between 2000 and 2017 at the Department of Hand and Plastic Surgery at Umeå University Hospital. The outcomes were implant survivorship and patient-reported outcome measures (PROMs) using the five-level EQ-5D version and The Knee Injury and Osteoarthritis Outcome Score.

RESULTS: Forty-seven patients (mean age = 67 years, 30 women) were included. The mean time between flap coverage and follow-up was 6.7 (±3.4) years. Implant survivorship was observed in 28 of 47 (59.6%) patients at follow-up. Flap failure was rare, with only 3 of 47 (6.4%) cases. Of the 20 patients who answered the PROMs, 10 of 20 experienced moderate to severe pain or discomfort.

CONCLUSIONS: Due to unfavorable underlying conditions, MGF reconstruction after TKA is often associated with a compromised functional outcome. Because donor site morbidity is limited and flap failure is unusual, the procedure can be considered prophylactically in a small subset of patients with risk factors to prevent soft tissue defects and periprosthetic joint infection.

Background: Women with an increased hereditary risk of breast cancer can undergo risk-reducing prophylactic mastectomy. However, there is a balance between how much subcutaneous tissue should be resected to achieve maximal reduction of glandular tissue, while leaving viable skin flaps.

Methods: Forty-five women previously operated with prophylactic mastectomy underwent magnetic resonance tomography (MRT) and ultrasound (US) to investigate the correlation between skin flap thickness and residual glandular tissue. Residual glandular tissue was documented as being present or not present, but not quantified, as the amount of residual glandular tissue in many cases was considered too small to make reliable volume quantifications with available tools. Since a mastectomy skin flap thickness of 5 mm is discussed as an oncologically safe thickness in the literature, this was used as a cut-off.

Results: Following prophylactic mastectomy, residual glandular tissue was detected in 39.3% of all breasts and 27.9% of all the breast quadrants examined by MRT, and 44.1% of all breasts and 21.7% of all the breast quadrants examined by US. Residual glandular tissue was detected in 6.9% of the quadrants in skin flaps ≤ 5 mm and in 37.5% of the quadrants in skin flaps > 5 mm (OR 3.07; CI = 1.41–6.67; p = 0.005). Furthermore, residual glandular tissue increased significantly already when the skin flap thickness exceeded 7 mm.

Conclusions: This study highlights that complete removal of glandular breast tissue during a mastectomy is difficult and suggests that this is an unattainable goal. We demonstrate that residual glandular tissue is significantly higher in skin flaps > 5 mm in comparison to skin flaps ≤ 5 mm, and that residual glandular tissue increases significantly already when the flap thickness exceeds 7 mm.

Introduction: Water jet-assisted liposuction has gained popularity due to favourable fat grafting outcomes. In this study, we compared stem cells obtained from fat isolated with manual or the water jet-assisted procedure.

Methods: Liposuction of abdominal fat was performed using the two methods on each donor (n = 10). Aspirate samples were collagenase digested and the isolated cells seeded in vitro prior to proliferation, adipogenic differentiation and angiogenic activity analyses.

Results: Cells from either procedure proliferated at similar rates and exhibited a similar colony-forming ability. The cells expressed stem cell markers CD73, CD90 and CD105. In the water jet cell preparations, there were higher numbers of cells expressing CD146. Robust adipogenic differentiation was observed in cultures expanded from both manual and water jet lipoaspirates. Gene analysis showed higher expression of the adipocyte markers aP2 and GLUT4 in the adipocyte-differentiated water jet cell preparations, and ELISA indicated increased secretion of adiponectin from these cells. Both cell groups expressed vasculogenic factors and the water jet cells promoted the highest levels of in vitro angiogenesis. Given these positive results, we further characterised the water jet cells when prepared using an automated closed cell processing unit, the Sepax-2 system (Cytiva). The growth and stem cell properties of the Sepax-processed cells were similar to the standard centrifugation protocol, but there was evidence for greater adipogenic differentiation in the Sepax-processed cells.

Conclusions: Water jet lipoaspirates yield cells with high adipogenic potential and angiogenic activity, which may be beneficial for use in cell-assisted lipotransfers.

Background: Women with an increased hereditary risk of breast cancer can undergo prophylactic mastectomy (PM), which provides a significant, but not total, risk reduction. There is an ongoing discussion about how much skin and subcutaneous tissue should be resected to perform an adequate PM while leaving viable skin flaps.

Methods: Forty-five women who had undergone PM were examined with magnetic resonance tomography (MRT), ultrasound (US) and clinical examination (CE) by a plastic surgeon and a general surgeon to estimate skin flap thickness.

Results: The estimated mean skin flap thickness after PM was 13.3 (± 9.6), 7.0 (± 3.3), 6.9 (± 2.8) and 7.4 (± 2.8) mm following MRT, US, and CE performed by a plastic surgeon and a general surgeon, respectively. The mean difference in estimated skin flap thickness was significant between MRT and the other measuring methods, while there was no significant difference between US and CE, nor between CE performed by the surgeons. The mean skin flap thickness was significantly affected by the age at PM. Following PM, necrosis was detected in 7/23 (30.4%) of the breasts in skin flaps ≤ 5 mm and in 5/46 (10.9%) of the breasts in skin flaps > 5 mm (OR 6.29; CI 1.20–32.94; p = 0.03).

Conclusion: The odds of getting postoperative necrosis was > 6 times higher in skin flaps ≤ 5 mm. Thus, if the degree of remaining glandular tissue is acceptably low, it is desirable to create skin flaps thicker than 5 mm to prevent wound healing problems after the PM procedure.

The ability to discriminate between diverse types of sensation is mediated by heterogeneous populations of peripheral sensory neurons. Human peripheral sensory neurons are inaccessible for research and efforts to study their development and disease have been hampered by the availability of relevant model systems. The in vitro differentiation of peripheral sensory neurons from human embryonic stem cells therefore provides an attractive alternative since an unlimited source of biological material can be generated for studies that specifically address development and injury. The work presented in this study describes the derivation of peripheral sensory neurons from human embryonic stem cells using small molecule inhibitors. The differentiated neurons express canonical- and modality-specific peripheral sensory neuron markers with subsets exhibiting functional properties of human nociceptive neurons that include tetrodotoxin-resistant sodium currents and repetitive action potentials. Moreover, the derived cells associate with human donor Schwann cells and can be used as a model system to investigate the molecular mechanisms underlying neuronal death following peripheral nerve injury. The quick and efficient derivation of genetically diverse peripheral sensory neurons from human embryonic stem cells offers unlimited access to these specialised cell types and provides an invaluable in vitro model system for future studies.

Peripheral nerve injuries induce significant sensory neuronal cell death in the dorsal root ganglia (DRG); however, the role of specific apoptotic pathways is still unclear. In this study, we performed peripheral nerve transection on adult rats, after which the corresponding DRGs were harvested at 7, 14, and 28 days after injury for subsequent molecular analyses with quantitative reverse transcription-PCR, western blotting, and immunohistochemistry. Nerve injury led to increased levels of caspase-3 mRNA and active caspase-3 protein in the DRG. Increased expression of caspase-8, caspase-12, caspase-7, and calpain suggested that both the extrinsic and the endoplasmic reticulum (ER) stress-mediated apoptotic pathways were activated. Phosphorylation of protein kinase R-like ER kinase further implied the involvement of ER-stress in the DRG. Phosphorylated protein kinase R-like ER kinase was most commonly associated with isolectin B4 (IB4)-positive neurons in the DRG and this may provide an explanation for the increased susceptibility of these neurons to die following nerve injury, likely in part because of an activation of the ER-stress response.

Introduction: Previously we showed that a fibrin glue conduit with human mesenchymal stem cells (hMSCs) and cyclosporine A (CsA) enhanced early nerve regeneration. In this study long term effects of this conduit are investigated. Methods: In a rat model, the sciatic nerve was repaired with fibrin conduit containing fibrin matrix, fibrin conduit containing fibrin matrix with CsA treatment and fibrin conduit containing fibrin matrix with hMSCs and CsA treatment, and also with nerve graft as control. Results: At 12 weeks 34% of motoneurons of the control group regenerated axons through the fibrin conduit. CsA treatment alone or with hMSCs resulted in axon regeneration of 67% and 64% motoneurons respectively. The gastrocnemius muscle weight was reduced in the conduit with fibrin matrix. The treatment with CsA or CsA with hMSCs induced recovery of the muscle weight and size of fast type fibers towards the levels of the nerve graft group. Discussion: The transplantation of hMSCs for peripheral nerve injury should be optimized to demonstrate their beneficial effects. The CsA may have its own effect on nerve regeneration.