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1.
Female hormones: do they influence muscle and tendon protein metabolism?
Hansen, M
The Proceedings of the Nutrition Society. 2018;(1):32-41
Abstract
Due to increased longevity, women can expect to live more than one-third of their lives in a post-menopausal state, which is characterised by low circulating levels of oestrogen and progesterone. The aim of this review is to provide insights into current knowledge of the effect of female hormones (or lack of female hormones) on skeletal muscle protein turnover at rest and in response to exercise. This review is primarily based on data from human trials. Many elderly post-menopausal women experience physical disabilities and loss of independence related to sarcopenia, which reduces life quality and is associated with substantial financial costs. Resistance training and dietary optimisation can counteract or at least decelerate the degenerative ageing process, but lack of oestrogen in post-menopausal women may reduce their sensitivity to these anabolic stimuli and accelerate muscle loss. Tendons and ligaments are also affected by sex hormones, but the effect seems to differ between endogenous and exogenous female hormones. Furthermore, the effect seems to depend on the age, and as a result influence the biomechanical properties of the ligaments and tendons differentially. Based on the present knowledge oestrogen seems to play a significant role with regard to skeletal muscle protein turnover. Therefore, oestrogen/hormonal replacement therapy may counteract the degenerative changes in skeletal muscle. Nevertheless, there is a need for greater insight into the direct and indirect mechanistic effects of female hormones before any evidence-based recommendations regarding type, dose, duration and timing of hormone replacement therapy can be provided.
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2.
Minimizing Injury and Maximizing Return to Play: Lessons from Engineered Ligaments.
Baar, K
Sports medicine (Auckland, N.Z.). 2017;(Suppl 1):5-11
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Abstract
Musculoskeletal injuries account for more than 70% of time away from sports. One of the reasons for the high number of injuries and long return to play is that we have only a very basic understanding of how our training alters tendon and ligament (sinew) structure and function. Sinews are highly dense tissues that are difficult to characterize both in vivo and in vitro. Recently, engineered ligaments have been developed in vitro using cells from human anterior cruciate ligaments or hamstring tendons. These three-dimensional tissues can be grown in a laboratory, treated with agents thought to affect sinew physiology, and then mechanically tested to determine their function. Using these tissues, we have learned that sinews, like bone, quickly become refractory to an exercise stimulus, suggesting that short (<10 min) periods of activity with relatively long (6 h) periods of rest are best to train these tissues. The engineered sinews have also shown how estrogen decreases sinew function and that a factor released following intense exercise increases sinew collagen synthesis and function. Last, engineered sinews are being used to screen possible nutritional interventions that may benefit tendon or ligament function. Using the data derived from these tissue-engineered sinews, new nutritional and training regimes are being designed and tested with the goal of minimizing injury and accelerating return to play.
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Tendons Involvement in Congenital Metabolic Disorders.
Abate, M, Salini, V, Andia, I
Advances in experimental medicine and biology. 2016;:117-22
Abstract
Congenital metabolic disorders are consequence of defects involving single genes that code for enzymes. Blocking metabolic pathways, the defect leads to the shortage of essential compounds, and/or to the accumulation of huge quantities of precursors, which interfere with normal functions. Only few of these diseases are characterized by a clinically significant tendon involvement.Heterozygous Familial Hypercholesterolaemia results from the inheritance of a mutant low-density lipoprotein receptor gene; patients show high cholesterol levels, precocious coronary artery disease, and may develop tendon xanthomata (mainly in Achilles tendon). The detection of xanthomata is important, because it allows an early diagnosis and treatment of the disorder. Cerebrotendinous Xanthomatosis is a rare genetic metabolic disorder of cholesterol and bile acid metabolism, characterized by accumulation of cholestanol in brain and tendons. Tendon abnormalities are similar to those reported in Heterozygous Familial Hypercholesterolaemia. Alkaptonuria is caused by a deficiency of the enzyme homogentisic acid oxidase. Due to the accumulation of the homogentisic acid, tendons and ligaments are characterized by a typical ochre/yellow pigmentation (ochronosis), with ensuing inflammation, calcification and rupture. In Congenital Hypergalactosemia an increased tendon collagen cross-linking by non-enzymatic galactosylation can be observed. Finally, Congenital Hypophosphatasia may be associated to deposition of hydroxyapatite crystals in rotator cuff, elbow, and Achilles tendons.
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4.
Is higher serum cholesterol associated with altered tendon structure or tendon pain? A systematic review.
Tilley, BJ, Cook, JL, Docking, SI, Gaida, JE
British journal of sports medicine. 2015;(23):1504-9
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Abstract
BACKGROUND Tendon pain occurs in individuals with extreme cholesterol levels (familial hypercholesterolaemia). It is unclear whether the association with tendon pain is strong with less extreme elevations of cholesterol. OBJECTIVE To determine whether lipid levels are associated with abnormal tendon structure or the presence of tendon pain. METHODS We conducted a systematic review and meta-analysis. Relevant articles were found through an electronic search of 6 medical databases-MEDLINE, Cochrane, AMED, EMBASE, Web of Science and Scopus. We included all case-control or cross-sectional studies with data describing (1) lipid levels or use of lipid-lowering drugs and (2) tendon structure or tendon pain. RESULTS 17 studies (2612 participants) were eligible for inclusion in the review. People with altered tendon structure or tendon pain had significantly higher total cholesterol, low-density lipoprotein cholesterol and triglycerides, as well as lower high-density lipoprotein cholesterol; with mean difference values of 0.66, 1.00, 0.33, and -0.19 mmol/L, respectively. CONCLUSIONS The results of this review indicate that a relationship exists between an individual's lipid profile and tendon health. However, further longitudinal studies are required to determine whether a cause and effect relationship exists between tendon structure and lipid levels. This could lead to advancement in the understanding of the pathoaetiology and thus treatment of tendinopathy.
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[RESEARCH PROGRESS OF STRATEGIES TO AUGMENT TENDON-TO-BONE HEALING].
Zhang, C, Li, Q, Tang, X, Li, J
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery. 2015;(7):912-6
Abstract
OBJECTIVE To summarize the application status and progress of the strategies to augment tendon-to-bone healing. METHODS The present researches focused on augmentation of tendon-to-bone healing were extensively reviewed. RESULTS The present strategies to augment healing of tendon-to-bone by enhancing the location environment, and increasing the cell numbers and relative growth factor. The mainly strategies include using calcium phosphate materials, biocompatible scaffolds and glue, growth factors, cell matrix, platelet-rich plasma, and periosteum. Although periosteum have been used in clinical and got some possitive effects, the others still not be used in clinical and needs further studies. CONCLUSION There are many strategies to enhance the ability of tendon-to-bone healing, which got some positive results, but results of studies were varied. Thus, further fundamental research and clinical studies are required to achieve the best effects.
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Ultrasonography in chondrocalcinosis.
Dufauret-Lombard, C, Vergne-Salle, P, Simon, A, Bonnet, C, Treves, R, Bertin, P
Joint bone spine. 2010;(3):218-21
Abstract
Ultrasonography can visualize calcific deposits within soft tissues. The appearance and location of the deposits distinguishes articular chondrocalcinosis from other crystal deposition diseases. The most common findings are hyperechoic dots or lines running parallel to the joint surface, hyperechoic images within fibrous cartilage (menisci and triangular fibrocartilage complex), and deposits within tendons (Achilles tendon). Studies found that ultrasonography was highly sensitive and specific for detecting calcifications, using calcium pyrophosphate dihydrate crystal detection in joint fluid as the reference standard. Good agreement has been demonstrated between radiographs and ultrasonography for the detection of calcifications. Thus, ultrasonography is valuable for diagnosing articular chondrocalcinosis via the detection of calcifications within the joint cartilage, fibrocartilage, and tendons. In addition, ultrasonography is a noninvasive, widely available, inexpensive investigation that requires no radiation exposure.
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New approaches and recent results concerning human-tissue collagen synthesis.
Smith, K, Rennie, MJ
Current opinion in clinical nutrition and metabolic care. 2007;(5):582-90
Abstract
PURPOSE OF REVIEW Knowledge of the physiological regulation of human-tissue collagen metabolism in vivo is poor, due to the lack of appropriately robust methods. Recent application of stable isotope tracer techniques to measure human collagen synthesis has provided some insights into the role of nutrition and exercise on collagen turnover in the extracellular matrix of the musculoskeletal system. RECENT FINDINGS Collagen turnover in the musculoskeletal system is faster than previously thought. Bone collagen synthesis is increased by feeding, whereas both muscle collagen and tendon are unresponsive. Exercise stimulates collagen synthesis in both muscle and tendon in an apparently coordinated manner. There are also sex differences and normal aging is associated with increased muscle collagen synthesis and reductions in bone collagen synthesis, particularly in mature bone collagen. SUMMARY Collagen turnover appears to be faster than previously thought and is regulated by feeding and exercise, in a tissue-specific manner. Further application of these approaches, coupled with measures of gene and protein expression, to measure the acute regulation of collagen, will lead to a better understanding of the physiology and pathophysiology of human collagen turnover. This is particularly important for developing new therapies to improve bone health and minimize tissue fibrosis.
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Trace elements in human tendons and ligaments.
Kumai, T, Yamada, G, Takakura, Y, Tohno, Y, Benjamin, M
Biological trace element research. 2006;(1-3):151-61
Abstract
Tendons and ligaments are key structures in promoting joint movement and maintaining joint stability. Although numerous reviews have detailed their structure, molecular composition, and biomechanical properties, far less attention has been paid to their content of trace elements. Tendons and ligaments are generally rich in calcium, sulfur, and phosphorus, although there are intriguing differences between one tendon/ligament and another. Furthermore, there can be significant regional variations that correlate with the presence or absence of fibrocartilage in the "wrap-around" regions of tendons or ligaments, where they change direction and press against bone. Here, their sulfate and calcium contents are particularly high. This is undoubtedly associated with the high levels of proteoglycans that are found in these cartilaginous tissues and the occasional presence of sesamoid bones within them.
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Adaptability of elderly human muscles and tendons to increased loading.
Narici, MV, Maganaris, CN
Journal of anatomy. 2006;(4):433-43
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Abstract
Senile sarcopenia, the loss of muscle mass associated with aging, is one of the main causes of muscle weakness and reduced locomotor ability in old age. Although this condition is mainly driven by neuropathic processes, nutritional, hormonal and immunological factors, as well as a reduction in physical activity, contribute to this phenomenon. Sarcopenia alone, however, does not fully account for the observed muscle weakness, as the loss of force is greater than that accounted for by the decrease in muscle size. As a consequence, a reduction in the force per unit area, both at single fibre and at whole muscle level, is observed. We recently suggested that at whole muscle level, this reduction in intrinsic force is the result of the combined effect of changes in (1) muscle architecture, (2) tendon mechanical properties, (3) neural drive (reduced agonist and increased antagonist muscle activity) and (4) single fibre-specific tension. Whereas several studies support the role of the last two factors in the loss of intrinsic muscle force with aging, alterations in muscle architecture and in tendon mechanical properties have also been shown to contribute to the above phenomenon. Indeed, sarcopenia of the human plantarflexors, represented by a 25% reduction in muscle volume, was found to be associated with a 10% reduction in fibre fascicle length and 13% reduction in pennation angle. These architectural alterations were accompanied by a 10% decrease in tendon stiffness, attributable to alterations in tendon material properties, as suggested by a 14% decrease in Young's modulus. Most of these changes may be reversed by 14 weeks of resistive training; both fibre fascicle length and tendon stiffness were found to be increased by 10 and 64%, respectively. Surprisingly, however, training had no effect on the estimated relative length-tension properties of the muscle, indicating that the effects of greater tendon stiffness and increased fascicle length cancelled out each other. It seems that natural strategies may be in place to ensure that the relative operating range of muscle remains unaltered by changes in physical activity, in old age.
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Assessment of skin, joint, tendon and muscle involvement.
Akesson, A, Fiori, G, Krieg, T, van den Hoogen, FH, Seibold, JR
Clinical and experimental rheumatology. 2003;(3 Suppl 29):S5-8
Abstract
This report makes recommendations for standardized techniques of data gathering and collection regarding: 1) skin involvement 2) joint and tendon involvement, and 3) involvement of the skeletal muscles. The recommendations in this report derive from a critical review of the available literature and group discussion. Committee recommendations are considered appropriate for descriptive clinical investigation, translational studies and as standards for clinical practice. Skin involvement should be assessed using the modified Rodnan skin score. Joint involvement, when symmetric synovitis is present, could be best assessed by the DAS-28 as is utilized in rheumatoid arthritis. Clinical assessment should include a routinized evaluation for the presence and number of palpable tendon friction rubs. Muscle involvement should be screened for by performance of the serum creatine phosphokinase assay and assessment of proximal weakness. More specific testing including EMG, magnetic resonance imaging and muscle biopsy should be employed in those patients with clinically significant myopathy only.