Exploring immune cell functions and ways to make use of them

In addition to host defense, alternative functions of immune cells are emerging. Immune cells are crucial during healing of injured tissue, in formation of new blood vessels, angiogenesis, and also in maintaining the balance in inflammation having immune regulating functions. Over the last decade a higher degree of heterogeneity and plasticity of immune cells have been reported and immune cells develop different characteristics in different situations in vivo. This thesis investigates roles for immune cells in situations of muscle hypoxia and reduced blood perfusion, wound healing in skin and at sites of transplantation of allogeneic islets of Langerhans and on top of this, ways to steer immune cell function for future therapeutic purposes. A specific neutrophil subset (CD49d+VEGFR1+CXCR4high) was found to be recruited to VEGF-A released at hypoxia and these neutrophils were crucial for functional angiogenesis. In muscle with restricted blood flow macrophages were detected in perivascular positions and started to express aSMA and PDGFR1b and were found to directly assist in blood flow regulation by iNOS-dependent NO production. This essential function in muscle regain of function could be boosted by plasmid overexpression of CXCL12 where the effect of these macrophages chaperoning the vasculature was amplified improving limb blood flow regulation. The effect on macrophages accelerating tissue regeneration being amplified by CXCL12 was tested in a model of cutaneous wound healing where the administration of CXCL12 was optimized for high bioavailability. In the skin, CXCL12-treatment induced accumulation of TGFb-expressing macrophages close to the wound driving the healing process, and subsequently the wounds healed with an efficiency never reported before. In the last study means to circumvent systemic immune suppressive therapy required in allogeneic transplantation was investigated. Allogeneic islets of Langerhans transplanted to muscle were immediately destroyed by the host immune system. Co-transplanting islets and CCL22-encoding plasmids we could curb this fast rejection for 10 days by accumulating CD4+CD25+FoxP3+ regulatory T lymphocytes at the site for transplantation preventing islet grafts from being attacked by the host cytotoxic T lymphocytes. In summary this thesis outlines distinct immune cell subsets being essential for regain of tissue function in hypoxia, ischemia and post injury and ways to amplify specific immune cell functions in these situations that are feasible for clinical use

Strategisk ekonomistyrning i små bioteknikbolag : En praktikfallsstudie

Branschen för bioteknik har länge varit stark i Sverige men har under de senaste åren utsatts för större konkurrens både vad gäller fler utländska satsningar och konkurrens om kapital nödvändigt för utveckling. Branschen karakteriseras av många små företag, innovationshöjd, höga tröskelkostnader för produktgodkännande samt stark reglering av produkter på marknaden. Företagen konkurrerar med olika strategier baserat på produkt och dess marknad. Det är tydligt att små företag i branschen inte själva täcker en hel värdekedja utan fokuserar sin kompetens på en del av kedjan. Företagen är i hög grad beroende av externa intressenter så som partners, distributörer och myndigheter. Arbetet syftar till att förstå om och hur dessa företag använder ekonomistyrning som stöd för strategiutveckling. Två praktikfall med tydligt olika strategier men liknande historia och storlek har studerats empiriskt och analyserats utifrån litteraturen. I båda fallen ses ett tydligt externt fokus och en kontinuerlig strategiutveckling. Externa parametrar viktiga för företagens strategiutveckling visade sig framförallt vara de direkt vetenskapliga men också hur marknaden förändras med avseende på reglering av licenser, patent och attityder till produkten. En viss systematik sågs i insamling av externa parametrar men på grund av osäkerheten i dess betydelse för företagens produkter samt företagens storlek saknades en plattform för behandling och systematisk analys av dessa. Klassisk ekonomistyrning användes som styrverktyg endast för korta perspektiv och var fokuserat på operationella mått. Sammanfattningsvis kan små bioteknikbolag med fördel använda strategisk ekonomistyrning i högre utsträckning för att säkrare och mer systematiskt behandla, analysera och integrera extern information som stöd för strategiutveckling.

The discovery and development of topical medicines for wound healing

Introduction: Chronic, nonhealing skin wounds claim >3% of the health-care budget in industrialized countries, and the incidence is rising. Currently, two parallel trends influence innovations within the field of wound healing: the need to reduce spread of antibiotic resistance and the emerging use of health economy and value-based models.Areas covered: This review focuses on the discovery of drug candidates and development of treatments aiming to enhance wound healing in the heterogeneous group of patients with nonhealing wounds.Expert opinion: Nonhealing wounds are multifaceted and recognized as difficult indications. The majority of products currently in use are medical device dressings, or concepts of negative pressure or hyperbaric oxygen treatment. Global best practice guidelines for the treatment of diabetic foot ulcers recommend debridement, redressing, as well as infection control, and are critical to the lack of coherent clinical evidence for many approved products in active wound care. To accelerate wound healing, there is an emerging trend toward biologics, gene therapy, and novel concepts for drug delivery in research and in the pipeline for clinical trials. Scientific delineation of the therapeutic mechanism of action is, in our opinion, vital for clinical trial success and for an increased fraction of medical products in the pharmaceutical pipeline

Shb deficiency in endothelium but not in leukocytes is responsible for impaired vascular performance during hindlimb ischemia.

Aim: Myeloid cells have been suggested to participate in angiogenesis and regulation of vascular function. Shb-deficient mice display both vascular and myeloid cell abnormalities with possible consequences for recovery after hindlimb ischemia. This study was conducted in order to assess the contribution of Shb-deficiency in myeloid cells to impaired vascular function in ischemia. Methods: Wild type and Shb-deficient mice were subjected to peritoneal VEGFA followed by intraperitoneal lavage, after which blood and peritoneal cells were stained for myeloid markers. VEGFA-induced leukocyte recruitment to cremaster muscle was investigated using intravital microscopy of both mouse strains. Blood flow after femoral artery ligation was determined on chimeric mice after bone marrow transplantation. Results: No differences in neutrophil numbers or cell surface phenotypes were detected. Moreover, neutrophil extravasation in VEGFA-activated cremaster muscle was unaffected by Shb deficiency. However, blood and peritoneal CXCR4+ monocytes/macrophages were reduced in response to intraperitoneal VEGFA but not LPS in the absence of Shb. Furthermore, the macrophage population in ischemic muscle was unaffected by Shb-deficiency after two days but reduced seven days after injury. The bone marrow transplantation experiments revealed that mice with wild type vasculature showed better blood flow than those with Shb-deficient vasculature irrespective of leukocyte genotype. Conclusion: The observed aberrations in myeloid cell properties in Shb-deficient mice are likely consequences of an abnormal vascular compartment and are not responsible for reduced muscle blood flow. Structural vascular abnormalities seem to be the primary cause of poor vascular performance under provoked vascular stress in this genetic model

Accelerated Wound Healing in Minipigs by On-Site Production and Delivery of CXCL12 by Transformed Lactic Acid Bacteria

Non-healing wounds are a growing medical problem and result in considerable suffering. The lack of pharmaceutical treatment options reflects the multistep wound healing process, and the complexity of both translation and assessment of treatment efficacy. We previously demonstrated accelerated healing of full-thickness wounds in mice following topical application of the probiotic bacteria Limosilactobacillus reuteri R2LC transformed to express CXCL12. In this study, safety and biological effects of a freeze-dried formulation of CXCL12-producing L. reuteri (ILP100) were investigated in induced full-thickness wounds in minipigs, and different wound healing evaluation methods (macroscopic, planimetry, 2D-photographs, 3D-scanning, ultrasound) were compared. We found that treatment with ILP100 was safe and accelerated healing, as granulation tissue filled wound cavities 1 day faster in treated compared to untreated/placebo-treated wounds. Furthermore, evaluation using planimetry resulted in 1.5 days faster healing than using 2D photographs of the same wounds, whereas the areas measured using 2D photographs were smaller compared to those obtained from 3D scans accounting for surface curvatures, whereas ultrasound imaging enabled detailed detection of thin epithelial layers. In conclusion, topical administration of the drug candidate ILP100 warrants further clinical development as it was proven to be safe and to accelerate healing using different evaluation methods in minipigs

Vascular adaptation to a dysfunctional endothelium as a consequence of Shb deficiency

Vascular endothelial growth factor (VEGF)-A regulates angiogenesis, vascular morphology and permeability by signaling through its receptor VEGFR-2. The Shb adapter protein has previously been found to relay certain VEGFR-2 dependent signals and consequently vascular physiology and structure was assessed in Shb knockout mice. X-ray computed tomography of vessels larger than 24 mm diameter (micro-CT) after contrast injection revealed an increased frequency of 48-96 µm arterioles in the hindlimb calf muscle in Shb knockout mice. Intravital microscopy of the cremaster muscle demonstrated a less regular vasculature with fewer branch points and increased vessel tortuosity, changes that led to an increased blood flow velocity. Reduced in vivo angiogenesis was observed in Shb knockout MatrigelTM plugs. Unlike the wild-type situation, VEGF-A did not provoke a dissociation of VE-cadherin from adherens junctions in Shb knockout venules. The reduced angiogenesis and altered properties of junctions had consequences for two patho-physiological responses to arterial occlusion: vascular permeability was reduced in the Shb knockout cremaster muscle after ligation of one supplying artery and heat-induced blood flow determined by Laser-Doppler measurements was decreased in the hindlimb after ligation of the femoral artery. Consequently, the Shb knockout mouse exhibited structural and functional (angiogenesis and vascular permeability) vascular abnormalities that have implications for understanding the function of VEGF-A under physiological conditions

The Use of Real-Life Examples in Biology Lessons to Develop Basic School Students' Scientific Literacy

Reālās dzīves situāciju piemēru izmantošana pamatskolas skolēnu dabaszinātniskās izpratības pilnveidei. Kristīne Stafecka, maģistra darba vadītājs Dr. paed. Rita Birziņa. Maģistra darbs – 77 lappuses, 23 literatūras avoti, 11 pielikumi, 20 attēli. Latviešu valodā. Darba mērķis ir noskaidrot, kā reālās dzīves situāciju piemēru izmantošana ietekmē skolēnu dabaszinātniskās izpratības pilnveidi bioloģijas stundās. Darba autore veica darbības pētījumu. Pētījuma laikā tika aprobēti autores izveidotie mācību materiāli – darba lapas, kas saturēja reālās dzīves situāciju piemērus. Pētījuma rezultāti liecina, ka reālās dzīves situācijas piemēru izmantošana var palīdzēt skolēniem uzlabot rezultātus pārbaudes darbos un pilnveidot mācību procesu. Skolēnu un skolotāju attieksme pret reālās dzīves piemēru izmantošanu mācību stundās ir pozitīva un ir izrādīta vēlme, lai tie tiktu izmantoti biežāk.The Use of Real-Life Examples in Biology Lessons to Develop Basic School Students' Scientific Literacy. Author of the Master Paper Kristīne Stafecka, Paper supervisor Dr. paed. Rita Birziņa. The Paper consists of 77 pages, 23 literary sources, 11 appendices and 20 pictures. The thesis is written in Latvian. The aim of the Thesis is to establish how student comprehension of scientific literacy is impacted by using examples of real life situations in biology lessons. The author of the Paper used action research. During the research the study materials, work books with real life situation examples created by the author of the Paper, have been approbated. The results of the research find that using examples of real life situations can help students to improve assessment results and study process. The attitude of both students and the teacher towards using the real life situation examples in study work is positive, and encourages more frequent use

Accelerated wound healing in mice by on-site production and delivery of CXCL12 by transformed lactic acid bacteria

Impaired wound closure is a growing medical problem associated with metabolic diseases and aging. Immune cells play important roles in wound healing by following instructions from the microenvironment. Here, we developed a technology to bioengineer the wound microenvironment and enhance healing abilities of the immune cells. This resulted in strongly accelerated wound healing and was achieved by transforming Lactobacilli with a plasmid encoding CXCL12. CXCL12-delivering bacteria administrated topically to wounds in mice efficiently enhanced wound closure by increasing proliferation of dermal cells and macrophages, and led to increased TGF-β expression in macrophages. Bacteria-produced lactic acid reduced the local pH, which inhibited the peptidase CD26 and consequently enhanced the availability of bioactive CXCL12. Importantly, treatment with CXCL12-delivering Lactobacilli also improved wound closure in mice with hyperglycemia or peripheral ischemia, conditions associated with chronic wounds, and in a human skin wound model. Further, initial safety studies demonstrated that the topically applied transformed bacteria exerted effects restricted to the wound, as neither bacteria nor the chemokine produced could be detected in systemic circulation. Development of drugs accelerating wound healing is limited by the proteolytic nature of wounds. Our technology overcomes this by on-site chemokine production and reduced degradation, which together ensure prolonged chemokine bioavailability that instructed local immune cells and enhanced wound healing.status: publishe

Aberrant association between vascular endothelial growth factor receptor-2 and VE-cadherin in response to vascular endothelial growth factor-a in Shb-deficient lung endothelial cells

Vascular permeability is a hallmark response to the main angiogenic factor VEGF-A and we have previously described a reduction of this response in Shb knockout mice. To characterize the molecular mechanisms responsible for this effect, endothelial cells were isolated from lungs and analyzed in vitro. Shb deficient endothelial cells exhibited less migration in a scratch wound-healing assay both under basal conditions and after vascular endothelial growth factor-A (VEGF-A) stimulation, suggesting a functional impairment of these cells in vitro. Staining for VE-cadherin and vascular endothelial growth factor receptor-2 (VEGFR-2) showed co-localization in adherens junctions and in intracellular sites such as the perinuclear region in wild-type and Shb knockout cells. VEGF-A decreased the VE-cadherin/VEGFR-2 co-localization in membrane structures resembling adherens junctions in wild-type cells whereas no such response was noted in the Shb knockout cells. VE-cadherin/VEGFR-2 co-localization was also recorded using spinning-disc confocal microscopy and VEGF-A caused a reduced association in the wild-type cells whereas the opposite pattern was observed in the Shb knockout cells. The latter expressed slightly more of cell surface VEGFR-2. VEGF-A stimulated extracellular-signal regulated kinase, Akt and Rac1 activities in the wild-type cells whereas no such responses were noted in the knockout cells. We conclude that aberrant signaling characteristics with respect to ERK, Akt and Rac1 are likely explanations for the observed altered pattern of VE-cadherin/VEGFR-2 association. The latter is important for understanding the reduced in vivo vascular permeability response in Shb knockout mice, a phenomenon that has patho-physiological relevance.De 2 första författarna delar förstaförfattarskapet.</p

Aberrant association between vascular endothelial growth factor receptor-2 and VE-cadherin in response to vascular endothelial growth factor-a in Shb-deficient lung endothelial cells

Vascular permeability is a hallmark response to the main angiogenic factor VEGF-A and we have previously described a reduction of this response in Shb knockout mice. To characterize the molecular mechanisms responsible for this effect, endothelial cells were isolated from lungs and analyzed in vitro. Shb deficient endothelial cells exhibited less migration in a scratch wound-healing assay both under basal conditions and after vascular endothelial growth factor-A (VEGF-A) stimulation, suggesting a functional impairment of these cells in vitro. Staining for VE-cadherin and vascular endothelial growth factor receptor-2 (VEGFR-2) showed co-localization in adherens junctions and in intracellular sites such as the perinuclear region in wild-type and Shb knockout cells. VEGF-A decreased the VE-cadherin/VEGFR-2 co-localization in membrane structures resembling adherens junctions in wild-type cells whereas no such response was noted in the Shb knockout cells. VE-cadherin/VEGFR-2 co-localization was also recorded using spinning-disc confocal microscopy and VEGF-A caused a reduced association in the wild-type cells whereas the opposite pattern was observed in the Shb knockout cells. The latter expressed slightly more of cell surface VEGFR-2. VEGF-A stimulated extracellular-signal regulated kinase, Akt and Rac1 activities in the wild-type cells whereas no such responses were noted in the knockout cells. We conclude that aberrant signaling characteristics with respect to ERK, Akt and Rac1 are likely explanations for the observed altered pattern of VE-cadherin/VEGFR-2 association. The latter is important for understanding the reduced in vivo vascular permeability response in Shb knockout mice, a phenomenon that has patho-physiological relevance.De 2 första författarna delar förstaförfattarskapet.</p