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Denne oppgaven er i sammarbeid med studentorganisasjonen ION Racing ved Universitetet i Stavanger. ION Racing er ett Formula Student lag som konkurerer i Formula Student konkuransen hvert år. Valget om å lage en motorkontroller ble gjort siden det var det eneste elektriske systemet på bilen som ikke var selvprodusert av ION Racing, og selvproduserte systemer gir høyere poengsum på konkurransen. Testing og design av motorkontrolleren har vært en verdifull, utfordrende og gøy opplevelse. Ett utviklingskort og ett driverkort ble brukt til å teste motorkontroll-algoritmer. På grunn av resolver mangel ble algoritmene bare delvis vellykket. Ett potensielt design har blitt utarbeidet, som kan bli videreutviklet. Motorkontrolleren ble ikke produsert innen oppgavens tidsfrist på grunn av produktmangel og tidsbegrensninger, men vil bli produsert og testet i fremtiden for 2024 bilen. This thesis is written in cooperation with the student organization ION Racing at the University of Stavanger. ION Racing is a formula student team that competes in the formula student competition each year. The choice to make a motor controller was made due to how it was the only electrical system that was not produced within ION Racing, and having self-produced systems gives a higher score at the competition. Testing and designing the motor controller has been a valuable, challenging and fun experience. A development board and a gate driver was used to test motor control algorithms. Due to resolver availability the algorithms were only partially successful. A potential design has been drafted, which can be expanded upon. In the end the MCU was not produced within the time of this thesis due to supply line challenges and time constraints, but will be produced and tested in the future for the 2024 car.

Background - We previously showed a tumor‐suppressive function of S100A14 in oral squamous cell carcinoma (OSCC). This study aimed to examine the prognostic significance and differentiation‐related function of S100A14 in OSCC. Methods - S100A14 expression was examined in 170 OSCCs from Norwegian and Nepalese populations using immunohistochemistry. Pro‐differentiation function was investigated by overexpressing and silencing S100A14 expression in OSCC‐derived cells. External transcriptomic datasets were used to validate association between S100A14 and differentiation markers in OSCC. Result - Loss of S100A14 expression at the invading tumor fronts significantly correlated with poor differentiation and reduced 10‐years survival of OSCC‐patients. Multivariate Cox analysis identified S100A14 to be an independent prognostic factor. Modulation of S100A14 expression in OSCC‐derived cells positively correlated with the expression of differentiation markers. Analysis of external datasets supported the pro‐differentiation function of S100A14. Conclusion - These results indicate that S100A14 is a pro‐differentiation protein and its expression might be useful as a prognostic marker in OSCC.

PurposeSeeking to improve the access to regenerative medicine, this study investigated the structural and transcriptional effects of storage temperature on human oral mucosal epithelial cells (OMECs).MethodsCells were stored at four different temperatures (4°C, 12°C, 24°C and 37°C) for two weeks. Then, the morphology, cell viability and differential gene expression were examined using light and scanning electron microscopy, trypan blue exclusion test and TaqMan gene expression array cards, respectively.ResultsCells stored at 4°C had the most similar morphology to non-stored controls with the highest viability rate (58%), whereas the 37°C group was most dissimilar with no living cells. The genes involved in stress-induced growth arrest (GADD45B) and cell proliferation inhibition (TGFB2) were upregulated at 12°C and 24°C. Upregulation was also observed in multifunctional genes responsible for morphology, growth, adhesion and motility such asEFEMP1(12°C) andEPHA4(4°C–24°C). Among genes used as differentiation markers,PPARAandTP53(along with its associated geneCDKN1A) were downregulated in all temperature conditions, whereasKRT1andKRT10were either unchanged (4°C) or downregulated (24°C and 12°C; and 24°C, respectively), except for upregulation at 12°C forKRT1.ConclusionsCells stored at 12°C and 24°C were stressed, although the expression levels of some adhesion-, growth- and apoptosis-related genes were favourable. Collectively, this study suggests that 4°C is the optimal storage temperature for maintenance of structure, viability and function of OMECs after two weeks.

Dry eye disease (DED) is a multifactorial syndrome that can be caused by alteration in the quality or quantity of the precorneal tear film. It is considered one of the most common ocular conditions leading patients to seek eye care. The current method for diagnostic evaluations and follow-up examinations of DED is a combination of clinical signs and symptoms determined by clinical tests and questionnaires, respectively. The application of powerful omics technologies has opened new avenues toward analysis of subjects in health and disease. Metabolomics is a new emerging and complementary research discipline to all modern omics in the comprehensive analysis of biological systems. The identification of distinct metabolites and integrated metabolic profiles in patients can potentially inform clinicians at an early stage or during monitoring of disease progression, enhancing diagnosis, prognosis, and the choice of therapy. In ophthalmology, metabolomics has gained considerable attention over the past decade but very limited such studies have been reported on DED. This paper aims to review the application of tear metabolomics in DED. publishedVersion

Hyaluronan (HA), a major component of the extracellular matrix, plays a key role in cell proliferation, growth, survival, polarization and differentiation. We investigated the optimization of a HA hydrogel scaffold for culture of human oral mucosal epithelial cells (OMECs) for potential application in limbal stem cell therapy. The effect of the optimized scaffold on OMEC cell sheet morphology, cell metabolic activity and expression of genes associated with stemness, adherence and cell damage was studied. The results indicate that HA hydrogels crosslinked with polyethylene glycol diacrylate (PEGDA) failed to support OMEC attachment and growth. However, HA hydrogel scaffolds dried for three days and coated with 1 mg/mL collagen IV produced a full OMEC sheet. Cell morphology was comparable to control after three weeks culture, maintaining 76% metabolic activity. Of apoptosis-related genes, the pro-apoptotic markers CASP3 and BAX2 were upregulated and downregulated, respectively, compared to control whereas the anti-apoptotic marker BCL2 was downregulated. The expression level of stemness genes &Delta, Np63&alpha, and ABCG2 was significantly higher than control. Genes associated with improved scar-less wound healing (integrin-V) and protection of the ocular surface (cadherin-1) had ~3-fold increased expression. These data suggest that our optimized HA-hydrogel scaffold could enhance culture of OMEC cell sheets for use in ocular reconstruction.

Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license Hyaluronan (HA), also termed hyaluronic acid or hyaluronate, is a major component of the extracellular matrix. This non-sulfated glycosaminoglycan plays a key role in cell proliferation, growth, survival, polarization, and differentiation. The diverse biological roles of HA are linked to the combination of HA’s physicochemical properties and HA-binding proteins. These unique characteristics have encouraged the application of HA-based hydrogel scaffolds for stem cell-based therapy, a successful method in the treatment of limbal stem cell deficiency (LSCD). This condition occurs following direct damage to limbal stem cells and/or changes in the limbal stem cell niche microenvironment due to intrinsic and extrinsic insults. This paper reviews the physical properties, synthesis, and degradation of HA. In addition, the interaction of HA with other extracellular matrix (ECM) components and receptor proteins are discussed. Finally, studies employing HA-based hydrogel scaffolds in the treatment of LSCD are reviewed

Purpose Electrospun polymer nanofibers present a structure similar to extracellular matrix (ECM) and support the surrounding cells. The type of polymer used, as well as the polymer blending-ratio, affects wettability. This in turn influences cell growth by altering the types of proteins adsorbed from the solution. Human corneal epithelial cells were grown on electrospun biodegradable and non-biodegradable polymer membranes to evaluate the membranes’ potential within ocular surface tissue engineering. Methods The electrospun polymer membranes consisted of cellulose acetate, poly (lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), and blends of PCL and polyethylene glycol (PEG). Expression of CDH1 (E-cadherin), ITGA6, ITGB4 (Integrin α6β4) and MKI67 (Ki67) genes were measured in all conditions after 14 days of culture using qRT-PCR. Results Cells seeded on all types of membranes expressed MKI67, which is associated with cell cycle activity and correlates with cell growth. MKI67 expression was high in cells grown on 3:2 blends of PCL and PEG (2.88) and PCL (2.75). This amount was 1.75, 1.00 and 1.59 for cells grown on cellulose acetate, 1:1 blend of PCL and PEG and PLGA respectively. The amount of ITGA6, ITGB4 expression was 1.72 in cells grown on PCL membranes, 1.10 for 3:2 blend of PCL and PEG, 1.05 for cellulose acetate, 1.53 for PLGA and 1.01 for 1:1 blend of PCL and PEG. Only cells grown on membranes containing blends of PCL: PEG showed CDH1 expression, which is critical for cell-cell contact. Conclusions All polymer membranes enabled cellular adhesion and proliferation. PCL:PEG and PCL membranes appear to promote the highest proliferative activity and strongest cell-membrane/cell-cell adhesion. Thus, these might be the most promising substrates for epithelial ocular surface tissue engineering.

ummary The anatomical and biological properties of stem cells in the eye have been the topic of indepth research over the last few decades. Enormous advances in the cell and tissue isolation and cultivation techniques, as well as molecular characterization of the different cell populations have been achieved, next to the major advances made in the bioscaffolds’ engineering for cell delivery and treatment of eye diseases. Advances in the cell and gene therapy have reached culmination with the human cornea being at the top and holding great promise in treating eye disorders. The eye is indeed a golden mine for stem cells. This session will include lectures from European experts in the field with high international recognition and large collaborative networks. Challenges in the clinical applications of cornea limbal stem cells will be described, along with advances in corneal endothelium engineering for future transplantation applications. In addition, examples of regulating the gene expression towards solving ocular surface diseases will be shown, as well as future directions hallmarking stem cell and cell therapy in ophthalmology.

Purpose Presently, our clinic is the only centre in Scandinavia that offers patients with corneal surface pathology including limbal stem cell deficiency (LSCD) transplantation of ex vivo expanded limbal epithelial cells (LECs). We here present clinical data of the first nine patients with LSCD who were transplanted with autologous LECs expanded in medium completely free of any animal-derived products and non-human/recombinant growth factors (including Cholera Toxin), and with autologous human serum as the only growth supplement. Methods We conducted a noncomparative retrospective study of patients with LSCD at our centre between 2009 and 2011. The diagnosis was based on history and clinical signs. A biopsy was taken from healthy limbus, and the epithelium was expanded on amniotic membrane (AM) in medium containing autologous serum and subsequently transplanted to the affected eye. Results Successful outcome was defined as relief of pain and photophobia and/or improved best corrected visual acuity (BCVA) and/or reestablishment of a stable corneal epithelium and regression of corneal vascularization. Five of the nine transplanted patients (55.6%) had an improvement in either subjective symptoms or objective findings (11- to 28-month follow-up). Conclusions Our clinical study shows that patients with LSCD can be treated successfully with transplantation of LECs expanded ex vivo in a medium with autologous serum as the only growth supplement. The use of this novel culture system, which is devoid of animal-derived products and non-human/recombinant growth factors (including Cholera Toxin), reduces the risks of inter-species disease transmission and host immune responses to xenogenic proteins, both obvious advantages for the patient.

Human mesenchymal stem cells (MSC) are popular candidates for tissue engineering. MSC are defined by their properties in two-dimensional (2D) culture systems. Cells in 2D are known to differ from their in vivo counterparts in cell shape, proliferation, and gene expression. Little is so far known about the phenotype and gene expression of cells in three-dimensional (3D) culture systems. To begin to unravel the impact of 3D versus 2D culture conditions on MSC, we have established MSC from adipose tissue and bone marrow in 3D cultures in alginate beads covalently modified with the tripeptide arginine-glycine-aspartic acid (RGD), the integrin-binding motif found in several molecules within the extracellular matrix. The MSC changed from their fibroblastoid shape (2D) to a small, compact shape when embedded in RGD alginate (3D). High viability was maintained throughout the experiment. The MSC retained expression of integrins known to bind RGD, and practically ceased to proliferate. Microarray analysis revealed that the gene expression in cells in RGD alginate was different both from the cells cultured in 2D and from prospectively isolated, uncultured MSC, but more similar to 2D cells. As alginate may be entirely dissolved, leaving the cells as single cell suspensions for various analyses, this represents a useful model for the study of cells in 3D cultures.

The purpose of this study was to evaluate the efficiency of using mesenchymal stem cells (MSC) in a hyaluronan scaffold for repair of an osteochondral defect in rabbit knee. Bone marrow was harvested from the posterior iliac crest in 11 New Zealand White rabbits. MSC were isolated and cultured in autologous serum for 28 days and transferred to a hyaluronan scaffold 24 h prior to implantation. A 4 mm diameter and 1.5 mm deep defect was created in the medial femoral condyle of both knees and the scaffold with MSC was implanted in one knee while an empty scaffold was implanted in the contra-lateral knee. After 24 weeks the rabbits were killed and histological sections were subjected to semiquantitative and quantitative evaluation by observers blinded regarding treatment modality. High degree of filling was obtained, but there was no statistically significant difference between the two treatments. However, there was a tendency for a better quality of repair in the MSC treated knees. No hypertrophy was observed by either method. MSC in a hyaluronan scaffold may be a promising treatment approach, but further studies are needed to determine the best combination of scaffold and cells.

Purpose p63 (isoform ΔNp63α) is a putative stemness marker for limbal epithelial stem cells (LESCs), and is essential for the proliferative potential of stem cells in stratified epithelia. The niche for LESCs is the limbus, located between the clear cornea and bulbar conjunctiva. LESCs are responsible for and able to renew and repair the corneal epithelium throughout life. In a number of disorders and after trauma, limbal stem cell deficiency (LSCD) may occur, and this can be treated by isolation and cultivation of LESCs from a healthy eye followed by transplantation to the affected eye. It is known that the percentage of p63-bright cells affect the success rate of the transplantation. Thus, we wanted to reveal whether lithium, a known Wnt signaling inducing agent, may increase the expression of p63 in human LESC cultures. Methods Small limbal biopsies (1x1-2mm) were dissected from donor corneas and cultured in a standard medium at 37 oC and 5% CO2 under different concentrations of lithium (LiCl2). The cells were cultured for 3-6 weeks and medium was changed every 2-3 days. Results The epithelial cells migrated from the limbal biopsy to form an epithelial sheet. Lithium enhanced the expression of p63 compared to controls, and this was confirmed by qRTPCR. Further studies mapping epigenetic alterations of the lithium treatment are currently conducted. Conclusion Lithium induced upregulation of p63 in LESC could be clinically important by increasing the long term success of limbal stem cell therapy.

Cell therapy is a promising treatment modality to improve heart function in acute myocardial infarction. However, the mechanisms of action and the most suitable cell type have not been finally determined. We performed a study to compare the effects of mesenchymal stem cells (MSCs) harvested from different tissues on LV function and explore their effects on tissue structure by morphometry and histological staining for species and lineage relationship. MSCs from skeletal muscle (SM-MSCs) and adipose tissue (ADSCs) were injected in the myocardium of nude rats 1 week after myocardial infarction. After 4 weeks of observation, LVEF was significantly improved in the SM-MSCs group (39.1%) and in the ADSC group (39.6%), compared to the placebo group (31.0%, p < 0.001 for difference in change between groups). Infarct size was smaller after cell therapy (16.3% for SM-MSCs, 15.8% for ADSCs vs. 26.0% for placebo, p < 0.001), and the amount of highly vascularized granulation tissue in the border zone was significantly increased in both groups receiving MSCs (18.3% for SM-MSCs, 22.6% for ADSCs vs. 13.1% for placebo, p = 0.001). By in situ hybridization, moderate engraftment of transplanted cells was found, but no transdifferentiation to cardiomyocytes, endothelial cells, or smooth muscle cells was observed. We conclude that MSC injections lead to improved LVEF after AMI in rats predominantly by reduction of infarct size. After 4 weeks, we observed modulation of scar formation with significant increase in granulation tissue. Transdifferentiation of MSCs to cardiomyocytes or vascular cells did not contribute significantly in this process. MSCs from skeletal muscle and adipose tissue had similar effects.

Purpose: Storage time for donor corneas in Optisol GS is limited compared to Eye Bank Organ Culture (EBOC). We here examine the epithelium on donor corneoscleral rims after primary storage in Optisol GS and subsequent incubation in EBOC. Methods: Morphology was monitored by light and electron microscopy, expression of phenotypic and genotypic markers by immunohistochemistry and RT-PCR and changes in oxidative lipid and DNA damage by ELISA and COMET assay. Results: A prominent loss of cells was observed after storage in Optisol GS. After maintenance in EBOC, spreading apical cells were Occludin+, while the staining for E-cadherin and Connexin-43 was less intense. There were an upregulation of Occludin and a downregulation of E-cadherin and Connexin-43. Eye Bank Organ Culture was associated with an ongoing proliferative activity and a downregulation of putative progenitor/stem cell marker ABCG2 and p63. Staining for 8-OHdG and Caspase-3 did not increase, while levels of malondialdehyde and number of DNA strand breaks and oxidized bases increased. Conclusions: This dual procedure should be pursued as an option to increase the storage time and the pool of available donor corneas. The observed downregulation of markers associated with stemness during EBOC is relevant considering the potential use of donor epithelium in the treatment of ocular surface disorders. Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://wileyonlinelibrary.com/onlineopen#\OnlineOpen_Terms

In patients with limbal stem cell deficiency (LSCD), transplantation of ex vivo expanded human limbal epithelial cells (HLECs) can restore the structural and functional integrity of the corneal surface. However, the protocol for cultivation and transplantation of HLECs differ significantly, and in most protocols growth additives such as cholera toxins, exogenous growth factors, hormones and fetal calf serum are used. In the present article, we compare for the first time human limbal epithelial cells (HLECs) cultivated on human amniotic membrane (HAM) in a complex medium (COM) including fetal bovine serum to a medium with human serum as single growth supplement (HSM), and report on our first examinations of HLECs expanded in autologous HSM and used for transplant procedures in patients with LSCD. Expanded HLECs were examined by genome-wide microarray, RT-PCR, Western blotting, and for cell viability, morphology, expression of immunohistochemical markers and colony forming efficiency. Cultivation of HLECs in HSM produced a multilayered epithelium where cells with markers associated with LESCs were detected in the basal layers. There were few transcriptional differences and comparable cell viability between cells cultivated in HSM and COM. The p63 gene associated with LESCs were expressed 3.5 fold more in HSM compared to COM, and Western blotting confirmed a stronger p63α band in HSM cultures. The cornea-specific keratin CK12 was equally found in both culture conditions, while there were significantly more CK3 positive cells in HSM. Cells in epithelial sheets on HAM remaining after transplant surgery of patients with LSCD expressed central epithelial characteristics, and dissociated cells cultured at low density on growth-arrested fibroblasts produced clones containing 21 ± 12% cells positive for p63α (n = 3). In conclusion, a culture medium without growth additives derived from animals or from animal cell cultures and with human serum as single growth supplement may serve as an equivalent replacement for the commonly used complex medium for ex vivo expansion of HLECs on HAM.

To obtain sufficient numbers of cells for tissue engineering applications, human bone marrow-derived mesenchymal stem cells (hBM-MSC) are commonly cultured as monolayers in incubators containing room air. In this study, we investigated whether three-dimensional (3D) culture conditions and incubator gas concentrations more similar to those observed in vivo impacted on cell expansion, differentiation capability, or phenotype of hBM-MSC. We found that 3D culture alone increased the expression of some molecules involved in osteogenic and adipogenic differentiation. In contrast, 3D culture did not induce chondrogenic differentiation, but enhanced the response to the chondrogenic differentiation medium. Changing the oxygen concentration to 6% and the carbon dioxide concentration to 7.5% did not impact on the results of any of our assays, showing that the hyperoxia of room air is not detrimental to hBM-MSC proliferation, differentiation, or phenotype.

In this study we have isolated human primary uncultured articular chondrocytes. When these cells are allowed to proliferate within their own extracellular matrix (ECM), they begin to produce hyaline ECM molecules similar to embryological chondroblasts. These cells are called chondroblast-like cells. Upon continued culture these cells spread onto the plastic surface and dedifferentiate. We have characterized these three stages of chondral cells by gene expression and expression of microRNAs (miRNAs) and proteins. Gene expression was quantified by real-time reverse transcriptase (RT) polymerase chain reaction, miRNA expression by miRNA arrays, and protein synthesis by extra- and intracellular flow cytometry. Many of the genes, miRNAs, and proteins were differentially expressed in the different stages of chondral cells. In the context of cellular therapy, expression of some genes is a cause for concern. The best source of cells for treatment of lesions of hyaline cartilage has not yet been identified. Adult chondroblast-like cells may be strong candidates. Profound understanding of how expression of genes and synthesis of proteins are regulated in these cells, for instance, by miRNAs, may reveal new strategies for improving their synthesis of hyaline ECM. This insight is important to be able to use these cells in the clinic.

Dette arbeidet handler om kvinner med minoritetsbakgrunn som kunne hatt ledelseskompetanse i norsk helsevesen, men av ulike grunner unngår eller ikke får jobbe i stillinger med ledelsesansvar. Det foreligger ulike årsaker, som eksempelvis i systemet hos arbeidsgivere, kalt for ytre barrierer, eller hos disse kvinnene selv, kalt for indre barrierer. Oppgaven er kombinert av litteratur og forskning gjort av andre og egen forskning som er basert på en kvalitativ undersøkelse i form av intervju. Resultat av undersøkelsen er forsøkt å sammenlignes med funn fra tidligere arbeid og forskning. Helsevesenet er et kvinnedominert arbeidsområde hvor relativt mange kvinner med utenlandsk bakgrunn møter større motstand i sin karriere enn det etnisk norske kvinner gjør. Andregenerasjons minoritetskvinner tar oftere høyere utdanninger og kommer bedre ut i karrieren. De tøffe minoritetskvinnene som kommer seg over barrierene klarer seg utmerket, og viser at en flerkulturell bakgrunn ikke er bare et hinder, men heller en fordel. Mange av disse kvinnene fremstår som rollemodeller for andre minoritetskvinner.

Culture of mesenchymal stem cells (MSCs) under conditions promoting proliferation and differentiation, while supporting genomic and epigenetic stability, is essential for therapeutic use. We report here the extent of genome-wide DNA gains and losses and of DNA methylation instability on 170 cancer-related promoters in bone marrow (BM) MSCs during culture to late passage in medium containing fetal bovine serum (FBS) or autologous serum (AS). Comparative genomic hybridization indicates that expansion of BMMSCs elicits primarily telomeric deletions in a subpopulation of cells, the extent of which varies between donors. However, late passage cultures in AS consistently display normal DNA copy numbers. Combined bisulfite restriction analysis and bisulfite sequencing show that although DNA methylation states are overall stable in culture, AS exhibits stronger propensity than FBS to maintain unmethylated states. Comparison of DNA methylation in BMMSCs with freshly isolated and cultured adipose stem cells (ASCs) also reveals that most genes unmethylated in both BMMSCs and ASCs in early passage are also unmethylated in uncultured ASCs. We conclude that (i) BMMSCs expanded in AS or FBS may display localized genetic alterations, (ii) AS tends to generate more consistent genomic backgrounds and DNA methylation patterns, and (iii) the unmethylated state of uncultured MSCs is more likely to be maintained in culture than the methylated state.

Articular chondrocytes (AC) expanded in vitro for tissue engineering rapidly turn off collagen type II (COL2) synthesis. We wanted to inhibit this process sufficiently to obtain therapeutically useful numbers of AC without losing COL2 synthesis. To this end, AC were expanded on their own extracellular matrix (ECM) in structures designated chondrocytes in autologous ECM (CA-ECM). Here, AC maintained a rounded shape and proliferated rapidly. After 13-15 days in culture, 40 x 10(6) cells (median) could be obtained from a cartilage biopsy. Real-time RT-PCR showed a reduced, but persistent, production of COL2A1 mRNA at this time. Flow cytometry showed high levels of intracellular COL2, and immunogold electron microscopy showed high density of well-organized COL2 fibrils in newly synthesized ECM. Interestingly, high levels of COL1A1 mRNA and intracellular protein were detected, but no COL1 was found in the ECM. The slow loss of COL2A1 mRNA was paralleled by a loss of the COL2 regulating transcription factor SOX9 mRNA. Chromatin immunoprecipitation assays could not identify epigenetic histone modifications that would explain the observed changes in COL2 synthesis. Thus, the CA-ECM strategy allows AC to proliferate to clinically useful numbers while maintaining COL2 synthesis and secretion. This strategy may improve tissue engineering of joint surfaces.

The Ca(2+)/Calmodulin-dependent protein kinase (CaMK) family is activated in response to elevation of intracellular Ca(2+), and includes CaMK1 (as well as CaMK2 and CaMK4), which exists as different isoforms (alpha, beta, gamma and delta). CaMK1 is present in several cell types and may be involved in various cellular processes, but its role in bone is unknown. In situ hybridization was used to determine the spatial and temporal expression of CaMK1beta during endochondral bone development in mouse embryos and newborn pups. The cellular and subcellular distribution of CaMK1 was assessed by quantitative immunogold electron microscopy (EM). The role of CaMK1beta in mouse calvarial osteoblasts was investigated by using small interfering RNA (siRNA) to silence its expression, while in parallel monitoring cell proliferation and levels of skeletogenic transcripts. cRNA in situ hybridization and EM studies show that CaMK1beta is mainly located in developing long bones and vertebrae (from ED14.5 until day 10 after birth), with highest expression in epiphyseal growth plate hypertrophic chondrocytes. By RT-PCR, we show that CaMK1beta2 (but not beta1) is expressed in mouse hind limbs (in vivo) and mouse calvarial osteoblasts (in vitro), and also in primary human articular chondrocyte cultures. Silencing of CaMK1beta in mouse calvarial osteoblasts by siRNA significantly decreases osteoblast proliferation and c-Fos gene expression (approx. 50%), without affecting skeletogenic markers for more differentiated osteoblasts (i.e. Cbfa1/Runx2, Osterix (Osx), Osteocalcin (Oc), Alkaline phosphatase (Alp) and Osteopontin (Opn)). These results identify CaMK1beta as a novel regulator of osteoblast proliferation, via mechanisms that may at least in part involve c-Fos, thus implicating CaMK1beta in the regulation of bone and cartilage development.

Tissue engineering is a new treatment strategy available to patients with injuries and diseases. The goal is to rebuild or replace damaged or dead tissue. The means is stem cells or differentiated organ specific cells, with or without scaffolds to ensure that the new tissue acquires the right shape. The present thesis is based on research performed within cell/stem cell biology, with the aim to improve treatment modalities in regenerative medicine. In order to ensure the best results from tissue engineering treatment strategies, the cells used need to be characterized in detail, and in vitro cell expansion protocols need to be optimalized. In his thesis, cand. scient Aboulghassem Shahdadfar has studied three cell populations with considerable potential in protocols in regenerative medicine. He identified mesenchymal stem cells (MSC) in adipose tissue, and defined their phenotype and gene expression. He showed that these cells could differentiate to several different lineages, and characterized the changes in gene expression induced in these cells by in vitro cell culture. Another population of MSC is found in the bone marrow. Using these cells, Shahdadfar showed that serum from the bone marrow donor could be used for in vitro cell expansion in stead of fetal calf serum, thus avoiding the risk of transfer of zoonoses and immune-stimulating xenogeneic proteins. The cells thus obtained seemed also to be more genetically stable. Chondrocytes obtained from biopsies of articular cartilage has for some time been used for treatment of focal lesions of the hyaline cartilage of the knee. However, in the course of in vitro culture these cells lose the ability to produce the right constituents of hyaline extracellular matrix. Shahdadfar in this thesis presents an improved cell culture method for chondrocytes, which ensures that the cells maintain the ability to produce the right extracellular matrix. Cells cultured in this way are already being used in patients.

The stromal compartment of mesenchymal tissues is thought to harbor stem cells that display extensive proliferative capacity and multilineage potential. Stromal stem cells offer a potentially large therapeutic potential in the field of regenerative medicine. Adipose tissue contains a large number of stromal stem cells, is relatively easy to obtain in large quantities, and thus constitutes a very convenient source of stromal stem cells. Importantly, the number of stem cells obtained is compatible with extensive analyses of the cells in an uncultured, freshly isolated, form. This chapter describes procedures for isolating millions of highly purified stromal stem cells from human adipose tissue and methods of establishing polyclonal and monoclonal cultures of adipose tissue-derived stem cells.

The stromal compartment of mesenchymal tissues is thought to harbor stem cells that display extensive proliferative capacity and multilineage potential. Stromal stem cells offer a potentially large therapeutic potential in the field of regenerative medicine. Adipose tissue contains a large number of stromal stem cells, is relatively easy to obtain in large quantities, and thus constitutes a very convenient source of stromal stem cells. Importantly, the number of stem cells obtained is compatible with extensive analyses of the cells in an uncultured, freshly isolated, form. This chapter describes procedures for isolating millions of highly purified stromal stem cells from human adipose tissue and methods of establishing polyclonal and monoclonal cultures of adipose tissue-derived stem cells.