Proliferation and differentiation potential of chondrocytes from osteoarthritic patients

Autologous chondrocyte transplantation (ACT) has been shown, in long-term follow-up studies, to be a promising treatment for the repair of isolated cartilage lesions. The method is based on an implantation of in vitro expanded chondrocytes originating from a small cartilage biopsy harvested from a non-weight-bearing area within the joint. In patients with osteoarthritis (OA), there is a need for the resurfacing of large areas, which could potentially be made by using a scaffold in combination with culture-expanded cells. As a first step towards a cell-based therapy for OA, we therefore investigated the expansion and redifferentiation potential in vitro of chondrocytes isolated from patients undergoing total knee replacement. The results demonstrate that OA chondrocytes have a good proliferation potential and are able to redifferentiate in a three-dimensional pellet model. During the redifferentiation, the OA cells expressed increasing amounts of DNA and proteoglycans, and at day 14 the cells from all donors contained type II collagen-rich matrix. The accumulation of proteoglycans was in comparable amounts to those from ACT donors, whereas total collagen was significantly lower in all of the redifferentiated OA chondrocytes. When the OA chondrocytes were loaded into a scaffold based on hyaluronic acid, they bound to the scaffold and produced cartilage-specific matrix proteins. Thus, autologous chondrocytes are a potential source for the biological treatment of OA patients but the limited collagen synthesis of the OA chondrocytes needs to be further explained

In Situ Labeling and Magnetic Resonance Imaging of Transplanted Human Hepatic Stem Cells

The purpose is to address the problem in magnetic resonance imaging (MRI) of contrast agent dilution

Vulnerability of the superficial zone of immature articular cartilage to compressive injury

Objective The zonal composition and functioning of adult articular cartilage causes depth-dependent responses to compressive injury. In immature cartilage, shear and compressive moduli as well as collagen and sulfated glycosaminoglycan (sGAG) content also vary with depth. However, there is little understanding of the depth-dependent damage caused by injury. Since injury to immature knee joints most often causes articular cartilage lesions, this study was undertaken to characterize the zonal dependence of biomechanical, biochemical, and matrix-associated changes caused by compressive injury. Methods Disks from the superficial and deeper zones of bovine calves were biomechanically characterized. Injury to the disks was achieved by applying a final strain of 50% compression at 100%/second, followed by biomechanical recharacterization. Tissue compaction upon injury as well as sGAG density, sGAG loss, and biosynthesis were measured. Collagen fiber orientation and matrix damage were assessed using histology, diffraction-enhanced x-ray imaging, and texture analysis. Results Injured superficial zone disks showed surface disruption, tissue compaction by 20.3 ± 4.3% (mean ± SEM), and immediate biomechanical impairment that was revealed by a mean ± SEM decrease in dynamic stiffness to 7.1 ± 3.3% of the value before injury and equilibrium moduli that were below the level of detection. Tissue areas that appeared intact on histology showed clear textural alterations. Injured deeper zone disks showed collagen crimping but remained undamaged and biomechanically intact. Superficial zone disks did not lose sGAG immediately after injury, but lost 17.8 ± 1.4% of sGAG after 48 hours; deeper zone disks lost only 2.8 ± 0.3% of sGAG content. Biomechanical impairment was associated primarily with structural damage. Conclusion The soft superficial zone of immature cartilage is vulnerable to compressive injury, causing superficial matrix disruption, extensive compaction, and textural alteration, which results in immediate loss of biomechanical function. In conjunction with delayed superficial sGAG loss, these changes may predispose the articular surface to further softening and tissue damage, thus increasing the risk of development of secondary osteoarthritis.National Institutes of Health (U.S.) (grant P5O-AR39239)National Institutes of Health (U.S.) (grant R01-AR45779)Deutsche Forschungsgemeinschaft (DFG) (grant RO 2511/1-1)Deutsche Forschungsgemeinschaft (DFG) (grant RO 2511/2-1

Human hepatic stem cells from fetal and postnatal donors

Human hepatic stem cells (hHpSCs), which are pluripotent precursors of hepatoblasts and thence of hepatocytic and biliary epithelia, are located in ductal plates in fetal livers and in Canals of Hering in adult livers. They can be isolated by immunoselection for epithelial cell adhesion molecule–positive (EpCAM+) cells, and they constitute ∼0.5–2.5% of liver parenchyma of all donor ages. The self-renewal capacity of hHpSCs is indicated by phenotypic stability after expansion for >150 population doublings in a serum-free, defined medium and with a doubling time of ∼36 h. Survival and proliferation of hHpSCs require paracrine signaling by hepatic stellate cells and/or angioblasts that coisolate with them. The hHpSCs are ∼9 μm in diameter, express cytokeratins 8, 18, and 19, CD133/1, telomerase, CD44H, claudin 3, and albumin (weakly). They are negative for α-fetoprotein (AFP), intercellular adhesion molecule (ICAM) 1, and for markers of adult liver cells (cytochrome P450s), hemopoietic cells (CD45), and mesenchymal cells (vascular endothelial growth factor receptor and desmin). If transferred to STO feeders, hHpSCs give rise to hepatoblasts, which are recognizable by cordlike colony morphology and up-regulation of AFP, P4503A7, and ICAM1. Transplantation of freshly isolated EpCAM+ cells or of hHpSCs expanded in culture into NOD/SCID mice results in mature liver tissue expressing human-specific proteins. The hHpSCs are candidates for liver cell therapies

Cryopreservation Effect on Proliferative and Chondrogenic Potential of Human Chondrocytes Isolated from Superficial and Deep Cartilage

[Abstract] Objectives: To compare the proliferative and chondrogenic potential of fresh and frozen chondrocytes isolated from superficial and deep articular cartilage biopsies. Materials and Methodology: The study included 12 samples of fresh and frozen healthy human knee articular cartilage. Cell proliferation was tested at 3, 6 and 9 days. Studies of mRNA quantification, protein expression and immunofluorescence for proliferation and chondrogenic markers were performed. Results: Stimulation of fresh and frozen chondrocytes from both superficial and deep cartilage with fetal bovine serum produced an increase in the proliferative capacity compared to the non-stimulated control group. In the stimulated fresh cells group, the proliferative capacity of cells from the deep biopsy was greater than that from cells from the superficial biopsy (0.046 vs 0.028, respectively, p<0.05). There was also a significant difference between the proliferative capacity of superficial zone fresh (0.028) and frozen (0.051) chondrocytes (p<0.05). CCND1 mRNA and protein expression levels, and immunopositivity for Ki67 revealed a higher proliferative capacity for fresh articular chondrocytes from deep cartilage. Regarding the chondrogenic potential, stimulated fresh cells showed higher SOX9 and Col II expression in chondrocytes from deep than from superficial zone (p<0.05, T student test). Conclusions: The highest rate of cell proliferation and chondrogenic potential of fresh chondrocytes was found in cells obtained from deep cartilage biopsies, whereas there were no statistically significant differences in proliferative and chondrogenic capacity between biopsy origins with frozen chondrocytes. These results indicate that both origin and cryopreservation affect the proliferative and chondrogenic potential of chondrocytes.Servizo Galego de Saúde; PS07/84Instituto de Salud Carlos III; CIBER BBN CB06-01-0040Ministerio Ciencia e Innovacion; PLE2009-0144Ministerio Ciencia e Innovación; PI 08/202

Effect of dynamic compressive loading and its combination with a growth factor on the chondrocytic phenotype of 3-dimensional scaffold-embedded chondrocytes

Background and purpose Three-dimensionally (3D-) embedded chondrocytes have been suggested to maintain the chondrocytic phenotype. Furthermore, mechanical stress and growth factors have been found to be capable of enhancing cell proliferation and ECM synthesis. We investigated the effect of mechanical loading and growth factors on reactivation of the 3D-embedded chondrocytes

Small animal models to understand pathogenesis of osteoarthritis and use of stem cell in cartilage regeneration

Osteoarthritis (OA) is one of the most common diseases, which affect the correct functionality of synovial joints and is characterized by articular cartilage degradation. Limitation in the treatment of OA is mostly due to the very limited regenerative characteristic of articular cartilage once is damaged. Small animal models are of particular importance for mechanistic analysis to understand the processes that affect cartilage degradation. Combination of joint injury techniques with the use of stem cells has been shown to be an important tool for understanding the processes of cartilage degradation and regeneration. Implementation of stem cells and small animal models are important tools to help researchers to find a solution that could ameliorate and prevent the symptoms of OA

Human articular chondrocytes. Plasticity and differentiation potentials

Articular cartilage has no or very low ability for self-repair and untreated lesions may lead tothe development of Osteoarthritis (OA). One method, which has been proved to result in longterm repair of isolated lesions, is autologous chondrocyte transplantation (ACT). In this methodculture expanded chondrocytes isolated from full-thickness biopsies taken from the supromedialedge, a non-weight bearing area of the femoral condyle, are transplanted back to the patientunder a cover of periosteum. To be able to improve the method and widen the treatmentindication to patients with fully developed OA, the general aim of this thesis was to increasethe knowledge of the cellular and molecular mechanisms underlying the repair tissue generatedby culture expanded chondrocytes.Our initial hypothesis to be tested was whether chondrocytes have stem cell properties. Thisquestion was addressed by using the established differentiation protocols for mesenchymalstem cells (MSCs) on culture expanded dedifferentiated human articular chondrocytes isolatedfrom non OA patients. The chondrocytes were found to exhibit a level of phenotypic plasticitythat is comparable with that of MSCs. By utilizing a cartilage selective agarose culture system,the plasticity of the cartilage progenitor cells was further shown to originate from clonal true chondrocytes and not from the heterogenous population of cells generated from acartilage biopsy that could harbor contaminating bone marrow stromal cells.By supplementing monolayer cultured chondrocytes with human serum instead of foetal calfserum a higher proliferative rate was achieved without losing the ability for cartilageredifferentiation in a 3D environment under serum free culture conditions. With microarraytechnology, the dynamic process of chondrocyte redifferentiation was shown to involve genesknown to be expressed in early embryonic chondrogenesis.Chondrocytes from OA patients were shown to have a proliferation potential in monolayercultures and an ability to redifferentiate in a pellet model at the same level as chondrocytesfrom non-OA patients. The cells could also be loaded into a hyaluronic acid based scaffold inwhich they did bind and produce cartilage proteoglycans and collagen. However, even if theOA cells produced cartilage specific matrix proteins, the cells did not produce the sameamount of total collagen as cells from patients without OA. The OA cells also continued theirproliferation within the redifferentiation model, indicating a potentially disturbed control intheir cell cycle.These findings demonstrate that treatment with ACT utilizes chondroprogenitor cells whichhave the potential to recapitulate embryonic genes during redifferentiation. This knowledgeis important for ongoing research in identifying strategies for regenerative therapies of othertissues and organs

Continuity - A quantitative study regarding continuity in the meeting between nurse and patient in two different surgical organizations.

Svensk hälso- och sjukvård har under de senaste decennierna förändrats och patienterna har idag kortare vårdtider och färre vårdplatser erbjuds samtidigt som antalet personer i vården ökat. Det här har medfört nya typer av vårdavdelningar såsom veckovård eller akutvårdsavdelningar. Den här förändringen har medfört att fokus har flyttats från patienten till organisationen vilket resulterar i att vården blivit fragmenterad. Vården måste vara sammanhängande och enhetlig för patienten ska uppleva att det finns tid för möten. Kontinuitet är grunden för att sjukvården ska kunna etablera en god kontakt med patienter som söker vård. En god relation bygger på det mänskliga mötet och där läggs grunden för att få en aktiv och deltagande patient, vilket den nya patientlagen eftersträvar och ger patienten mandat för. En aktiv och deltagande patient ger också en mer patientsäker och personcentrerad vård. Syfte Studien undersöker kontinuiteten mellan patient och patientansvarig sjuksköterska inom två olika kirurgiska organisationer. Metod En kvantitativ, retrospektiv journalgranskning. Resultat För att kunna jämföra vårdtillfällen mellan de två kirurgiska organisationernas olika långa vårdtider konstruerades kontinuitetsfaktorn. Kontinuitetsfaktorn är antalet patientansvariga sjuksköterskor som patienten möter dividerat med antalet arbetspass under vårdtillfället. Vårdenhet Ortopedi (Ort) hade en bättre kontinuitet än vårdenheten för kirurgisk akutvård (KAVA). Vårdenhet Ort låg på den bättre halvan av kontinuitetsintervallet och Vårdenhet KAVA precis på gränsen. Endast ett av hundra granskade vårdtillfällen hade optimal kontinuitet i mötet mellan patientansvarig sjuksköterska och patient. Diskussion Även om de två undersökta kirurgiska organisationerna uppvisade kontinuitetsfaktorvärden som låg inom den bättre halvan av kontinuitetsintervallet eller precis på gränsen mellan bättre och sämre kontinuitet så anser vi att det finns utrymme för förbättringar. Många förbättringar skulle kunna genomföras med relativt enkla medel som till exempel att minimera antalet enkelarbetspass för patientansvarig sjuksköterska hos en given patient. Swedish Healthcare has changed during the last decades and today patients have shorter length of stay in hospitals and hospital beds have decreased at the same time as the number of healthcare workers have increased. New types of hospital wards have emerged like for example weekly wards and acute hospital wards. This has changed focus from the patient to the organization which makes care fragmented. Healthcare needs to be coherent and homogenous so that patients can experience that there is time for meetings. The foundation of continuity in healthcare is to establish a good relationship with patients seeking care. A good relationship is based on the human encounter and leads to an active and participating patient. This is what the new law for patient aims at and give patients mandate for. An active and participating patient results in a more safe and personcentered care. Purpose The study examines the continuity between patient and responsible nurse in two surgical organizations. Method A quantitative, retrospective review of medical journals. Results To be able to compare length of stays in hospital between the two surgical organizations a continuity factor was constructed. The Continuity factor consists of the number of nurses the patient meets divided with the number of work shifts during the length of stays. The Orthopedic ward (Ort) showed better continuity than the ward for acute surgical care (KAVA). Ward Ort was situated on the better half of the continuity interval and Ward KAVA was situated on the limit between better and worse continuity. Only one out of a hundred examined lengths of stays showed optimal continuity in the meeting between nurse and patient. Discussion Even though the two examined surgical organizations showed a value of continuity factor that was situated on the better half of the continuity interval or just on the limit between better and worse continuity we think there is room for improvements. Many improvements could be done with relatively simple contributions, like for example to minimize the number of single work shifts for nurses assigned to a patient