Effects of Hormones on Bone Cells in Elderly People and Their Influence on Osteopenia

Abstract Due to the increasing survival of middle and old age groups, elderly population worldwide is increasing. Increasing age is associated with a generalized deterioration of systemic organ functions. The endocrine system that releases hormones into the blood circulation for regulation of bodily functions is one of the physiological systems highly affected by age-related degeneration. Osteopenia is a progressive loss of bone matrix characterized by reduced bone density. The alteration of hormone levels in an aging population has a direct impact on bone cells, and therefore the potential to develop osteopenia. The pathophysiology of osteopenia is complex, but one of the major causes of bone mass loss associated with aging appears to be changed within the levels of endogenous hormone networks that regulate bone synthesis and breakdown. This brief review describes the physiology of bone growth, bone formation and bone remodeling. It then describes the effects of hormone regulation, as hormone changes with aging, and therefore the likelihood of the development of osteopenia. Lastly, this review provides information relating to preventative treatment of osteopenia and the maintenance of bone mass. Keywords: hormone, osteopenia, bone cells, old age and endocrine syste

Efecto de la hormona de crecimiento, el plasma rico en plaquetas y la brushita sobre la regeneración ósea

Desde los tiempos míticos, el hombre ha soñado con la posibilidad de que sus tejidos dañados por la enfermedad, las heridas o la senescencia pudiesen ser regenerados y sustituidos por unos nuevos plenos de vida La medicina regenerativa o Ingeniería Tisular es una de las ramas de la investigación biomédica que más se ha desarrollado en los últimos años y que al mismo tiempo presenta unas perspectivas de futuro prometedoras. Desde un punto de vista un tanto academicista, que permite simplificar el abordaje del tema, consideramos que esta estrategia terapéutica se basa en tres pilares..

Pharmakogenetik der Wachstumshormonsubstitution bei Hypophysenvorderlappeninsuffizienz: Der Collagen-I-alpha-1-SP1-Polymorphismus

Es besteht ein COLIa1-SP1-Polymorphismus assoziierter Effekt auf die individuell subkutan applizierte benötigte hGH-Dosis bei GH-defizienten adulten Patienten. TT-homozygote Polymorphismus-Genotypen (5%) benötigen eine signisfikant niedrigere hGH-Dosis als die GG-homozygoten Genotypen (GG 65%, GT 30%). Erklärungsthese: Veränderung der subkutenen Kollagenstruktur und damit Diffusionskapazität aufgrund einer Veränderung des COLIa1/COLIa2-Quotienten

Efecto de la hormona del crecimiento y los estrógenos en el hueso osteoporótico: Análisis morfométrico en ratas Wistar. Estudio piloto.

La osteoporosis es una enfermedad sistémica esquelética que afecta a más de 200 millones de personas en el mundo. Es la enfermedad ósea más frecuente y la mayoría de las personas que la padecen, no van a ser conscientes hasta que no se produce una fractura. Se sabe desde hace tiempo que el déficit de estrógenos está implicado en la etiopatogenia de la osteoporosis, sin embargo, el déficit de otras hormonas, como la hormona de crecimiento (GH) y el aumento del estrés oxidativo constituyen uno de los más recientes descubrimientos en cuanto a los factores etiopatogénicos. Los tratamientos actuales contra la osteoporosis no carecen de efectos secundarios importantes, como la osteonecrosis de los maxilares y las fracturas subtrocantéreas atípicas. Aunque su prevalencia es baja, se están buscando nuevas alternativas terapéuticas eficaces y seguras. Se sabe que la GH está implicada en el crecimiento longitudinal del hueso y que es capaz de estimular la proliferación y diferenciación de osteoblastos y osteoclastos, es decir, de estimular el proceso de remodelado. Por otro lado, los estrógenos están implicados en la etiopatogenia de la osteoporosis y se utilizan en la terapia hormonal sustitutiva para tratar los síntomas de la menopausia. Sin embargo, por lo que nosotros sabemos, nunca se han empleado GH y estrógenos conjuntamente como tratamiento contra la osteoporosis. Por ello, el propósito de este estudio piloto fue evaluar el efecto que la GH y los estrógenos, pudieran tener en el hueso osteoporótico de un animal de experimentación, tanto de manera conjunta como por separado. Asimismo, se estudió el efecto de la ovx en diferentes áreas óseas en tibias de ratas viejas. Material y método: Para realizar este estudio piloto se utilizaron 25 ratas Wistar hembras viejas divididas aleatoriamente en 5 grupos experimentales, cada uno de ellos con 5 animales. Un grupo de 5 ratas se mantuvo como grupo control, y a los cuatro restantes se les realizó una ovariectomía bilateral (ovx). De estos cuatro grupos, uno quedó sin tratamiento, actuando como grupo ovx control, otro fue tratado con GH sc (2 mg/kg/día), otro con estradiol sc (125 µg/semana) y otro con una combinación de ambas, es decir, GH (2 mg/kg/día) más estradiol (125 µg/semana), todos ellos tratados durante 10 semanas. Tras ese período de tiempo, los animales fueron sacrificados por decapitación. Las tibias de los animales fueron extraídas, se eliminaron los tejidos blandos y se fijaron en formaldehido al 10% tamponado a pH 7. Se cortaron en bloques de 2 cm, que se incluyeron en metacrilato (2-hidroxietil-metacrilato), para posteriormente ser cortadas y pulidas mediante el sistema de corte y pulido Exakt. Las muestras se tiñeron con tricrómico de Masson y hematoxilina-eosina y se observaron al microscopio óptico. Se realizó un estudio morfométrico mediante el sistema MIP-4, midiendo: Área Ósea, Área Cortical y Área Trabecular y porosidad cortical. Se realizó el análisis estadístico de las medias con el programa SPSS 22.0 mediante la prueba de ANOVA para buscar significación estadística, considerando significativo si p<0,05. Resultados: Se pudo observar que la ovx disminuía el área ósea, el área cortical y el área trabecular, mientras que aumentaba la porosidad cortical, aunque las diferencias no alcanzaron significatividad estadística. La administración sistémica de GH en ratas ovx aumentaba significativamente el área ósea (5,47±0,13 vs 4,53±0,17) y el área cortical (5,34±0,16 vs 0,42±0,20), respecto al grupo ovx control, mientras que el área trabecular y la porosidad cortical aumentaron, pero de forma no significativa. Respecto a los estrógenos no indujeron diferencias significativas en ningún parámetro estudiado. La administración conjunta de GH+estrógenos en ratas ovx aumentó el área ósea (5,18±0,60 vs 4,53±0,17) de manera significativa respecto a las ratas ovx sin tratamiento (p=0,02). El resto de los parámetros estudiados no alcanzó significatividad estadística. Conclusiones: La deprivación estrogénica mediante la ovx bilateral no indujo diferencias significativas en el área ósea, área cortical, área trabecular o porosidad cortical. La administración sistémica de GH a dosis de 2 mg/kg/día en ratas ovx incrementó de forma significativa el área ósea y el área cortical medidas por morfometría, respecto al grupo ovx control. La administración de estrógenos no indujo diferencias significativas en las ratas ovx respecto al grupo ovx control. La administración conjunta de GH+estrógenos incrementó de forma significativa el área ósea en ratas ovx, respecto al grupo ovx control

Zelluläre Seneszenz mesenchymaler Stammzellen unter oxidativem Stresseinfluss

Degenerative Gelenkerkrankungen erlangen vor dem Hintergrund des demographischen Wandels zunehmend an Bedeutung. Die therapeutischen Möglichkeiten von Knorpeldefekten sind bis dato limitiert. Mesenchymale Stammzellen tragen in vivo zur Geweberegeneration bei und stellen eine attraktive Zellquelle für das Tissue engineering dar. Ähnlich wie somatische Zellen stellen MSCs nach einer gewissen Anzahl von Zellteilungen die Proliferation ein und treten in das Stadium der Seneszenz über. Oxidativer Stress gilt als einer der wichtigsten Faktoren in der multifaktoriellen Genese zellulärer Seneszenz. Ziel dieser Arbeit war es den Einfluss von chronisch niedrig dosiertem und akutem subletalen oxidativen Stress auf Morphologie, Proliferationsverhalten, Telomerlänge und Genexpression humaner mesenchymaler Stammzellen zu untersuchen. Akuter Einfluss subletaler Stressdosen führte zu Wachstumsstopp, seneszenzähnlichen morphologischen Veränderungen und erhöhter SA-ß-Galactosidaseexpression. Chronischer niedrig dosierter oxidativer Stress hatte keine relevanten Auswirkungen auf Morphologie und Proliferationsverhalten. Chronischer Stresseinfluss hatte jedoch einen signifikant erhöhten Telomerverlust zur Folge. Nach akuter oxidativer Stresseinwirkung zeigte sich ein signifikanter Anstieg der p21 Expression. Die TRF1 Expression war signifikant erniedrigt, während TRF2 leicht vermehrt exprimiert wurde. Die Expression von SIRT1 und XRCC5 war nach akuter oxidativer Stresseinwirkung signifikant erhöht. Bei präseneszenten Zellen fiel der Expressionsanstieg sogar noch deutlicher aus als bei jungen Zellen. Im Vergleich zu Fibroblasten und Chondrozyten zeigten MSCs im Hinblick auf Proliferationsverhalten, Morphologie, Telomerbiologie und Genexpression eine erhöhte Widerstandsfähigkeit gegenüber oxidativem Stress. Weitere Erforschung bezüglich der komplexen molekularbiologischen Mechansimen zellulärer Seneszenz könnte möglicherweise eine gezielte Beeinflussung der Zellalterung in vitro und in vivo ermöglichen

The role of H2B monoubiquitination in cellular differentiation

Histones, subjected to post-translational modifications, are important regulators of the cellular processes. One of these modifications is monoubiquitination of histone H2B (H2Bub1). H2Bub1 is associated with the actively transcribed genes. Moreover, H2Bub1 is required for the proper DNA repair and was recently reported to be lost during tumor progression. The levels of H2Bub1 in the cell are tightly regulated. In mammals, ubiquitination is mediated by the E3 ubiquitin ligase RNF20/40. Another important upstream regulator of H2Bub1 is the CDK9 enzyme that promotes transcriptional elongation. It, together with an adaptor protein WAC, facilitates the RNF20/40 recruitment to the chromatin. Differentiation of the cell is a process that results in cellular specialization and acquiring a physiological function. It is accompanied by the significant changes in gene expression and in histone modification patterns. This project aimed to understand the role of H2Bub1 in cellular differentiation. Investigating human mesenchymal stem cells (hMSCs) it was observed that the H2Bub1 levels increase during differentiation into osteoblasts and adipocytes. Depletion of the H2Bub1 regulators RNF40, WAC and CDK9 resulted in inhibition of the hMSC differentiation suggesting that H2Bub1 is required for the correct progression of this process. Mechanistically, H2Bub1 was shown to participate in the activation of the “bivalent” genes that carry activatory and inhibitory histone marks. H2Bub1 deposition is required for removal of the repressive H3K27me3 from the differentiation-dependent genes. Taken together, these observations for the first time demonstrate the involvement of H2Bub1 in cellular differentiation. The proposed model suggests that H2Bub1 executes its function via promoting the resolution of bivalency on the differentiation-specific genes. These results give additional insights into H2Bub1 function during transcription of the certain subsets of genes. The obtained knowledge increases our understanding of the transcriptional regulation, carcinogenesis and stem cell biology

Auxiologische Untersuchung bei Kindern mit Wachstumshormonmangel vor und unter der Substitutionstherapie mit Wachstumshormon

Einleitung: Wachstumsprozesse beim gesunden Menschen sind weitgehend untersucht und bekannt. Über die Auswirkungen von stark erniedrigtem bzw. fehlendem Wachstumshormon auf das Längen- und Breitenwachstum einzelner auxiologischer Parameter und die Folgen einer Wachstumshormonsubstitutionstherapie auf die Körperproportionen im Einzelnen weiß man außer den Kenntnissen über die Körperhöhenveränderungen wenig. Fragestellung: Ziel dieser Arbeit war die auxiologische Untersuchung von Kindern mit Wachstumshormonmangel vor und unter einer Substitutionstherapie mit Wachstumshormon. im Vordergrund stand die Erkennung bestimmter auxiologischer Muster vor und die Frage nach Veränderungen der Körperproportionen unter der Therapie. Methode: Grundlage der Daten sind 62 Kinder mit idiopathischem und 20 Kindern mit organischem Wachtumshormonmangel, bei denen über einen maximalen Zeitraum von fünf Jahren halbjährlich 22 verschiedene Parameter vermessen und drei weitere berechnet worden sind. Ergebnisse: Die phänotypischen Merkmale des hypophysären Kleinwuchses vor Substitutionsbeginn (Puppengesicht, Akromikrie, pyknomorpher Körperbau) sind Ausdruck bestimmter auxiologischer Konstellationen, die Längenparameter weichen signifikant stärker als die Breitenparameter vom Altersnormwert ab. In Abhängigkeit von der Therapiedauer kommt es durch unterschiedlich stark ausgeprägte Größenzuwachsraten im Verhältnis zum Längenwachstum insbesondere bei der Unterarmlänge, den Breiten- und Tiefenmaßen des Thorax und den Kopfmaßen zu Veränderungen der Körperproportionen. In der Regel verbessern sich die Ausgangsproportionen. Der relative Körperfettgehalt, sowie die Umfänge (Brust-, Taillen- und Hüftumfang) nehmen unter der Therapie in Relation zur Körperhöhe ab. Schlussfolgerung: Anhand der vorliegenden Daten wird gezeigt, dass die Substitutionstherapie mit Wachstumshormon beim hypophysären Kleinwuchs Auswirkungen auf das Längen- und Breitenwachstum einzelner auxiologischer Parameter hat und sich von physiologischem Wachstum unterscheidet. Für die Bestätigung unserer Beobachtungen sind weitere prospektive Untersuchungen in größeren Kollektiven notwendig.Introduction: Processes of growth in healthy children are well established. However, little is known about the effects of strongly degraded or missing growth hormone on the lengths and breadths growth of single axiological parameters. In particular, changes of body proportions under hormone replacement therapy are not known. Objective: The aim of the study was to estimate the influence of growth hormone deficiency of single axiological parameters and changes in body proportions during replacement therapy with growth hormone. Patients/Material and Methods: Subjects studied include 62 children with idiopathic growth hormone deficiency and 20 children with organic reason of growth hormone deficiency. 22 anthropometric measurements per person were taken by the same trained examiner prior to the start of GH-treatment and then every six months over a maximal period of 5 years. Results: Results give a distinct anthropometric picture before start of therapy. All linear parameters were significantly below average, while width measurements differed less. During treatment changes of the body proportions occur due to different growth rates of measured distances compared to height growth. The most positive changes were seen in the upper arm, hand and feet growth under GH-therapy. A comparable low growth was seen in forearm length, chest width and depth and head measures. The growth dynamics of the other parameters correspond to that of height itself. Conclusion: It is shown that the replacement therapy with growth hormone has different effects on the length and width growth of different bones. The growth is different from physiological growth processes in patient with growth hormone deficiency. Further prospective examinations are necessary to confirm our observations in larger collectives

Metabolic effects and long-term safety of childhood growth hormone treatment

The overall aim of this thesis was to investigate the metabolic effects and long-term safety of childhood growth hormone (GH) treatment. In order to achieve this aim, the different projects consist of a two-part clinical trial on metabolic features linked to GH physiology and GH treatment as well as two large population-based cohort studies with focus on the long-term cardiovascular and cancer risks in previously GH-treated patients. In study I, the metabolic profile of 35 prepubertal children of short stature, between 7 and 10 years of age, with stimulated peak GH levels in the lower normal range (7-14 µg/L) was compared to 12 age- and sex-matched control children of normal height and weight. The groups were compared using blood samples of fasting glucose and insulin, HbA1c, insulin-like growth factor I (IGF-I), insulin sensitivity using both homeostasis model assessment of insulin resistance (HOMA-IR) and frequently sampled intravenous glucose tolerance test (FSIVGTT), dual-energy x-ray absorptiometry (DEXA), microdialysis and stable isotope examination of glucose production and lipolysis. Few differences between the groups were found but the subgroup of children with the lowest GH peak levels demonstrated lower fasting insulin levels and signs of increased insulin sensitivity. In study II, the 35 short children from study I were subsequently randomized to three different doses of recombinant human GH (rhGH) treatment; low dose (11 µg/kg/d), standard dose (33 µg/kg/d) or high dose (100 µg/kg/d), and followed for two years. The doses were blinded to both patients and the study investigators. The metabolic effects of the different treatment doses were analyzed by the same methods as in study I and a clear dose-dependent metabolic effect could be demonstrated, in particular for the high dose group regarding fasting insulin and different measures of insulin sensitivity. In study III, the long-term cardiovascular morbidity in childhood rhGH-treated Swedish patients between 1985 and 2010, due to isolated GH deficiency (GHD), small for gestational age (SGA) or idiopathic short stature (ISS), was investigated. Data on cardiovascular outcomes and important covariates were gathered for a total of 3,408 patients and 50,036 randomly selected controls matched on sex, age and county. Time to first cardiovascular event was analyzed by Cox proportional-hazard regression models and the study showed increased adjusted hazard ratios for the patients compared to the controls. In study IV, the long-term cancer incidence and mortality in a large meta-cohort of approximately 24,000 previously childhood rhGH-treated patients from eight European countries were investigated. The results did not support an overall carcinogenic effect of rhGH treatment but the significant trend of increased cancer mortality risk in relation to rhGH dose in patients with previous cancer and the indication of possible effects on bone cancer, bladder cancer and Hodgkin’s lymphoma requires further vigilance

A novel method of articular cartilage repair.

Articular cartilage repair of post-traumatic articular cartilage defects and well-defined articular cartilage pathology is challenging in clinical practice and has been the focus of investigations for many years. In the present thesis a newly developed polymer system, based on poly-ethyl-methacrylate PEMA polymer and tetra-hydro-furfuryl methacrylate THFMA monomer has been exploited for the repair of large, full-thickness articular cartilage defects, created in a weight-bearing surface in the rabbit knee joint. The method of implantation is simple and easily reproducible and can be performed in one stage with open arthrotomy or arthroscopy in clinical applications. Intravenous administration of the monomer did not elicit significant cardiorespiratory side effects. The repair tissue in defects treated with PEMA/THFMA was compared to control defects that healed 'naturally'. Macroscopic and histological/histochemical evaluation using the newly developed Articular Cartilage Repair Scoring System, immunohistochemistry, electron microscopy, image analysis as well as biochemical analysis were used for the characterisation of the repair tissue. The results demonstrated that the PEMA/THFMA polymer enhanced significantly the quality of repair up to 1 year postoperatively. The repair tissue contained numerous chondrocytes producing large amounts of proteoglycans and collagen type II, and it was completely bonded to the adjacent normal articular cartilage in the vast majority of the specimens. The enhancing effect of PEMA/THFMA in articular cartilage defects was also demonstrated in three age groups of rabbits at 6 weeks, thus increasing the potential clinical applications of the polymer. Furthermore, PEMA/THFMA was compared to the conventional bone cement PMMA/MMA. At 6 weeks post-implantation PEMA/THFMA produced significantly superior repair tissue, compared to PMMA/MMA, confirming the importance of the properties of the new polymer. Finally, PEMA/THFMA was exploited as a potential drug delivery system in vivo by loading human growth hormone in the polymer. It was shown that the loaded polymer repaired the defects with a proliferative type of tissue, resembling immature articular cartilage