Modelling of ecological coherences in small mountainous streams using macroinvertebrates with special regard to morphology and land use

Fließgewässer wurden in der Vergangenheit zahlreichen anthropogenen Einflüssen unterworfen. Die im Dezember 2000 in Kraft getretene EU-Wasserrahmenrichtlinie (WRRL) hat zum Ziel, diesen Prozess umzukehren, das heißt, die Gewässer möglichst in den guten ökologischen Zustand zurückzuführen, wobei die Beurteilung des ökologischen Zustandes erstmalig primär anhand organismischer Gruppen erfolgen soll. Vor diesem Hintergrund verfolgte die Arbeit im Wesentlichen zwei Ziele: - Erstellung eines Systems zur Bewertung struktureller Degradation für den Fließgewässertyp 5 (grobmaterialreiche, silikatische Mittelgebirgsbäche) anhand des Makrozoobenthos, - Quantifizierung des Einflusses von Landnutzung im Einzugsgebiet und Strukturen an einer Probestelle auf die organismische Bewertung. Die Erstellung des Bewertungssystems wurde auf Grundlage qualitativ hochwertiger, einheitlicher Datensätze vorgenommen, die aus dem Forschungsvorhaben AQEM und STAR stammten. Darin wurden quantitative Aufsammlungen des Makrozoobenthos an insgesamt 31 Gewässerabschnitten im Rheinischen Schiefergebirge durchgeführt (multi-habitat-sampling nach AQEM). Parallel dazu wurde eine Vielzahl gewässermorphologischer Parameter aufgenommen, um die strukturelle Ausstattung der Abschnitte numerisch zu dokumentieren. Die Probestellen deckten dabei eine Degradationsreihe von naturnah über mäßig bis schlecht ab – keine der Stellen war saprobiell belastet. Die aus den Aufsammlungen gewonnenen biologischen Kenngrößen (Metriks) wurden mit den Strukturparametern korreliert, um diejenigen Metriks zu ermitteln, die am besten den morphologischen Zustand der Gewässer widerspiegelten. Die am besten geeigneten Metriks wurden anschließend in verschiedenen Zusammenstellungen kombiniert, miteinander verrechnet und das Ergebnis erneut mit den Strukturen korreliert. Das endgültige Bewertungssytem enthält insgesamt sechs Metriks: Anteil Steinfliegen, Deutscher Faunaindex, Margalef-Diversität, Anteil Krenal, Anteil Phytal und Anteil Sedimentfresser. Die Ergebnisse dieser Metriks werden standardisiert, in eine Skala von 0 bis 1 überführt und über einfache Mittelwertbildung verrechnet. Zur Ermittlung des Einflusses der Landnutzung wurden die Einzugsgebiete kategorisiert nach den Nutzungsarten Siedlungsflächen, landwirtschaftliche Flächen und Waldflächen. Mittels digitaler Karten des Landesvermessungsamtes NRW wurden die jeweiligen Anteile der Nutzungskategorien ermittelt, und zwar auf drei verschiedenen räumlichen Betrachtungsebenen: zum einen auf der Fläche gesamter Einzugsgebiete, zum anderen innerhalb schmaler Korridore entlang der Gewässerläufe: entlang aller Hauptzuläufe (bis zu ihren Quellen) und in einem Streifen bis zu 2 Kilometer oberhalb einer Probestelle. Mittels der Methode der multiplen Regression (in Kombination mit multivariaten Verfahren) wurden unabhängige Größen (Struktur- und Nutzungsvariablen) mit einer abhängigen Größe (Bewertungsergebnis) zu einem Modell verrechnet. Innerhalb der Strukturen stellten sich die folgenden Parameter als am bedeutsamsten für die strukturelle Situation einer Probestelle heraus: Anteil Uferlinie mit Gehölzbestand, Eintiefung und Anteil unbefestigter Ufer. Innerhalb der Nutzungen stellte sich heraus, dass die folgenden Kategorien die Bewertungsergebnisse am wirksamten beeinflussen: Siedlungsflächen (bis zu 2 km oberhalb einer Probestelle), Waldflächen (bis zu 2 km oberhalb einer Probestelle) und Waldflächen (gesamter Gewässerkorridor). Mit 37 % besitzen Strukturparameter den größten Einfluss auf ein Bewertungsergebnis; Nutzungsparameter beeinflussen dieses zu 31 % und die Quellhöhe, als zusätzlich wirksamer Faktor, zu 22 %. Lediglich 10 % der Varianz im Bewertungsindex konnten nicht erklärt werden. Die Ergebnisse zeigen, dass die alleinige Betrachtung lokaler Gegebenheiten nicht ausreicht, um die Effizienz beispielsweise von Renaturierungsmaßnahmen abzuschätzen, sondern dass eine gesamtheitliche Betrachtung des gesamten Fließgewässersystems vonnöten ist, da Nutzungen eine mitentscheidende Einflussgröße in der Ökologie von Fließgewässern spielen können

Human osteochondritis dissecans fragment-derived chondrocyte characteristics ex vivo, after monolayer expansion-induced de-differentiation, and after re-differentiation in alginate bead culture

Background Autologous chondrocyte implantation (ACI) is a therapy for articular cartilage and osteochondral lesions that relies on notch- or trochlea-derived primary chondrocytes. An alternative cell source for ACI could be osteochondritis dissecans (OCD) fragment-derived chondrocytes. Assessing the potential of these cells, we investigated their characteristics ex vivo and after monolayer expansion, as monolayer expansion is an integral step of ACI. However, as monolayer expansion can induce de-differentiation, we asked whether monolayer-induced de-differentiation can be reverted through successive alginate bead culture. Methods Chondrocytes were isolated from the OCD fragments of 15 patient knees with ICRS grades 3–4 lesions for ex vivo analyses, primary alginate bead culture, monolayer expansion, and alginate bead culture following monolayer expansion for attempting re-differentiation. We determined yield, viability, and the mRNA expression of aggrecan and type I, II, and X collagen. Results OCD fragment-derived chondrocyte isolation yielded high numbers of viable cells with a low type I:II collagen expression ratio ( 1. Conclusion OCD fragment derived human chondrocytes may hold not yet utilized clinical potential for cartilage repair. Keywords: Chondrocyte; Articular cartilage; De-differentiation Re-differentiation; Monolayer expansion; Alginate bead cultur

Bioresponsive microspheres for on‐demand delivery of anti‐inflammatory cytokines for articular cartilage repair

Despite innovations in surgical interventions, treatment of cartilage injury in osteoarthritic joints remains a challenge due to concomitant inflammation. Obstructing a single dominant inflammatory cytokine has shown remarkable clinical benefits in rheumatoid arthritis, and similar strategies are being suggested to target inflammatory pathways in osteoarthritis (OA). Here, we describe the utility of gelatin microspheres that are responsive to proteolytic enzymes typically expressed in arthritic flares, resulting in on‐demand and spatiotemporally controlled release of anti‐inflammatory cytokines for cartilage preservation and repair. These microspheres were designed with a net negative charge to sequester cationic anti‐inflammatory cytokines, and the magnitude of the negative charge potential increased with an increase in crosslinking density. Collagenase‐mediated degradation of the microspheres was dependent on the concentration of the enzyme. Release of anti‐inflammatory cytokines from the loaded microspheres directly correlated with the degradation of the gelatin matrix. Exposure of the IL‐4 and IL‐13 loaded microspheres reduced the inflammation of chondrocytes up to 80%. Hence, the delivery of these microspheres in an OA joint can attenuate the stimulation of chondrocytes and the resulting secretion of catabolic factors such as proteinases and nitric oxide. The microsphere format also allows for minimally invasive delivery and is less susceptible to mechanically induced drug release. Consequently, bioresponsive microspheres can be an effective tool for cartilage preservation and arthritis treatment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153665/1/jbma36852_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153665/2/jbma36852.pd

Proliferative remodeling of the spatial organization of human superficial chondrocytes distant from focal early osteoarthritis

Objective Human superficial chondrocytes show distinct spatial organizations, and they commonly aggregate near osteoarthritic (OA) fissures. The aim of this study was to determine whether remodeling or destruction of the spatial chondrocyte organization might occur at a distance from focal (early) lesions in patients with OA. Methods Samples of intact cartilage (condyles, patellofemoral groove, and proximal tibia) lying distant from focal lesions of OA in grade 2 joints were compared with location-matched nondegenerative (grade 0–1) cartilage samples. Chondrocyte nuclei were stained with propidium iodide, examined by fluorescence microscopy, and the findings were recorded in a top-down view. Chondrocyte arrangements were tested for randomness or significant grouping via point pattern analyses (Clark and Evans Aggregation Index) and were correlated with the OA grade and the surface cell densities. Results In grade 2 cartilage samples, superficial chondrocytes were situated in horizontal patterns, such as strings, clusters, pairs, and singles, comparable to the patterns in nondegenerative cartilage. In intact cartilage samples from grade 2 joints, the spatial organization included a novel pattern, consisting of chondrocytes that were aligned in 2 parallel lines, building double strings. These double strings correlated significantly with an increased number of chondrocytes per group and an increased corresponding superficial zone cell density. They were observed in all grade 2 condyles and some grade 2 tibiae, but never in grade 0–1 cartilage. Conclusion This study is the first to identify a distinct spatial reorganization of human superficial chondrocytes in response to distant early OA lesions, suggesting that proliferation had occurred distant from focal early OA lesions. This spatial reorganization may serve to recruit metabolically active units as an attempt to repair focal damage.National Institutes of Health (U.S.) (grant P5O-AR39239)National Institutes of Health (U.S.) (grant R01-AR33236)Deutsche Forschungsgemeinschaft (DFG) (grant RO 2511/1-1)Deutsche Forschungsgemeinschaft (DFG) (grant RO 2511/2-1

Assessing streams in Germany with benthic invertebrates: development of a practical standardised protocol for macroinvertebrate sampling and sorting

AbstractIn the past, no single standardised method for sampling and sorting benthic macroinvertebrates has been implemented in Germany. Therefore, we tested the suitability of two common sorting protocols, RIVPACS and AQEM/STAR, by taking samples with each protocol at 44 sampling sites. Our results reveal that different methods deliver slightly different assessment results. Moreover these two methods differ in costs. Although the AQEM/STAR protocol takes longer than the RIVPACS protocol, we favoured the AQEM/STAR protocol because of its higher level of standardisation. In order to limit costs to an acceptable level, a modification of the AQEM/STAR protocol (MAS method) is developed. This method is highly standardised, gives stable assessment results and is relatively inexpensive (€ 224.00 for processing of an average sample). A detailed protocol of the newly developed method is given

A matter of origin - identification of SEMA3A, BGLAP, SPP1 and PHEX as distinctive molecular features between bone site-specific human osteoblasts on transcription level

In oral and maxillofacial bone reconstruction, autografts from the iliac crest represent the gold standard due to their superior clinical performance, compared to autografts derived from other extraoral regions. Thus, the aim of our study was to identify putative differences between osteoblasts derived from alveolar (hOB-A) and iliac crest (hOB-IC) bone of the same donor (nine donors) by means of their molecular properties in 2D and 3D culture. We thereby focused on the gene expression of biomarkers involved in osteogenic differentiation, matrix formation and osteoclast modulation. Furthermore, we examined the transcriptional response to Vit.D3 in hOB-A and hOB-IC. Our results revealed different modulation modes of the biomarker expression in osteoblasts, namely cell origin/bone entity-dependent, and culture configuration- and/or time-dependent modulations. SEMA3A, SPP1, BGLAP and PHEX demonstrated the strongest dependence on cell origin. With respect to Vit.D3-effects, BGLAP, SPP1 and ALPL displayed the highest Vit.D3-responsiveness. In this context we demonstrated that the transcriptional Vit.D3-response concerning SPP1 and ALPL in human osteoblasts depended on the cell origin. The results indicate a higher bone remodeling activity of iliac crest than alveolar osteoblasts and support the growing evidence that a high osteoclast activity at the host-/donor bone interface may support graft integration

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

Stress-vs-time signals allow the prediction of structurally catastrophic events during fracturing of immature cartilage and predetermine the biomechanical, biochemical, and structural impairment

Objective Trauma-associated cartilage fractures occur in children and adolescents with clinically significant incidence. Several studies investigated biomechanical injury by compressive forces but the injury-related stress has not been investigated extensively. In this study, we hypothesized that the biomechanical stress occurring during compressive injury predetermines the biomechanical, biochemical, and structural consequences. We specifically investigated whether the stress-vs-time signal correlated with the injurious damage and may allow prediction of cartilage matrix fracturing. Methods Superficial and deeper zones disks (SZDs, DZDs; immature bovine cartilage) were biomechanically characterized, injured (50% compression, 100%/s strain-rate), and re-characterized. Correlations of the quantified functional, biochemical and histological damage with biomechanical parameters were zonally investigated. Results Injured SZDs exhibited decreased dynamic stiffness (by 93.04 ± 1.72%), unresolvable equilibrium moduli, structural damage (2.0 ± 0.5 on a 5-point-damage-scale), and 1.78-fold increased sGAG loss. DZDs remained intact. Measured stress-vs-time-curves during injury displayed 4 distinct shapes, which correlated with histological damage (p < 0.001), loss of dynamic stiffness and sGAG (p < 0.05). Damage prediction in a blinded experiment using stress-vs-time grades was 100%-correct and sensitive to differentiate single/complex matrix disruptions. Correlations of the dissipated energy and maximum stress rise with the extent of biomechanical and biochemical damage reached significance when SZDs and DZDs were analyzed as zonal composites but not separately. Conclusions The biomechanical stress that occurs during compressive injury predetermines the biomechanical, biochemical, and structural consequences and, thus, the structural and functional damage during cartilage fracturing. A novel biomechanical method based on the interpretation of compressive yielding allows the accurate prediction of the extent of structural damage.National Institutes of Health (U.S.) (Grant R01-AR45779)Deutsche Forschungsgemeinschaft (Grant RO2511/1-1)Deutsche Forschungsgemeinschaft (Grant RO2511/2-1)Germany. Federal Ministry of Education and Research (Grant 01KQ0902B TP2

The geometrical shape of mesenchymal stromal cells measured by quantitative shape descriptors is determined by the stiffness of the biomaterial and by cyclic tensile forces

Controlling mesenchymal stromal cell (MSC) shape is a novel method for investigating and directing MSC behaviour in vitro. it was hypothesized that specifigc MSC shapes can be generated by using stiffnessâ defined biomaterial surfaces and by applying cyclic tensile forces. Biomaterials used were thin and thick silicone sheets, fibronectin coating, and compacted collagen type I sheets. The MSC morphology was quantified by shape descriptors describing dimensions and membrane protrusions. Nanoscale stiffness was measured by atomic force microscopy and the expression of smooth muscle cell (SMC) marker genes (ACTA2, TAGLN, CNN1) by quantitative reverseâ transcription polymerase chain reaction. Cyclic stretch was applied with 2.5% or 5% amplitudes. Attachment to biomaterials with a higher stiffness yielded more elongated MSCs with fewer membrane protrusions compared with biomaterials with a lower stiffness. For cyclic stretch, compacted collagen sheets were selected, which were associated with the most elongated MSC shape across all investigated biomaterials. As expected, cyclic stretch elongated MSCs during stretch. One hour after cessation of stretch, however, MSC shape was rounder again, suggesting loss of stretchâ induced shape. Different shape descriptor values obtained by different stretch regimes correlated significantly with the expression levels of SMC marker genes. Values of approximately 0.4 for roundness and 3.4 for aspect ratio were critical for the highest expression levels of ACTA2 and CNN1. Thus, specific shape descriptor values, which can be generated using biomaterialâ associated stiffness and tensile forces, can serve as a template for the induction of specific gene expression levels in MSC. Copyright © 2017 John Wiley & Sons, Ltd.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141253/1/term2263.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141253/2/term2263_am.pd