scholarly journals A Tribological Comparison of Facet Joint, Sacroiliac Joint, and Knee Cartilage in the Yucatan Minipig

Cartilage ◽  
2021 ◽  
pp. 194760352110219
Author(s):  
Rachel C. Nordberg ◽  
M. Gabriela Espinosa ◽  
Jerry C. Hu ◽  
Kyriacos A. Athanasiou
Keyword(s):  
Coefficient Of Friction ◽  
Facet Joint ◽  
Treatment Options ◽  
Tribological Characteristics ◽  
Large Animal ◽  
Large Animal Models ◽  
Friction Testing ◽  
Si Joint ◽  
Cervical Facet ◽  
Lumbar Facet

Objective Pathology of the facet and sacroiliac (SI) joints contributes to 15% to 45% and 10% to 27% of lower back pain cases, respectively. Although tissue engineering may offer novel treatment options to patients suffering from cartilage degeneration in these joints, the tribological characteristics of the facet and SI joints have not been studied in either the human or relevant large animal models, which hinders the development of joint-specific cartilage implants. Design Cartilage was isolated from the knee, cervical facet, thoracic facet, lumbar facet, and SI joints of 6 skeletally mature Yucatan minipigs ( Sus scrofa). Tribological characteristics were assessed via coefficient of friction testing, interferometry, and immunohistochemistry for lubricin organization. Results Compared with the knee, the coefficient of friction was higher by 43% in the cervical facet, 77% in the thoracic facet, 37% in the lumbar facet, and 28% in the SI joint. Likewise, topographical features of the facet and SI joints varied significantly, ranging from a 114% to 384% increase and a 48% to 107% increase in global and local surface roughness measures, respectively, compared with the knee. Additionally, the amount of lubricin in the SI joint was substantially greater than in the knee. Statistical correlations among the various tribological parameters revealed that there was a significant correlation between local roughness and coefficient of friction, but not global roughness or the presence of lubricin. Conclusion These location-specific tribological characteristics of the articular cartilages of the spine will need to be taken into consideration during the development of physiologically relevant, functional, and durable tissue-engineered replacements for these joints.

scholarly journals Large Animal Models of Heart Failure: Reduced vs. Preserved Ejection Fraction

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1906 ◽  
Author(s):  
Christopher J. Charles ◽  
Miriam T. Rademaker ◽  
Nicola J. A. Scott ◽  
A. Mark Richards
Keyword(s):  
Heart Failure ◽  
Clinical Trials ◽  
Animal Models ◽  
Ejection Fraction ◽  
Treatment Options ◽  
Large Animal ◽  
Reduced Ejection Fraction ◽  
Large Animal Models ◽  
Sampling Protocols ◽  
Underlying Mechanisms

Heart failure (HF) is the final common end point of multiple metabolic and cardiovascular diseases and imposes a significant health care burden worldwide. Despite significant improvements in clinical management and outcomes, morbidity and mortality remain high and there remains an indisputable need for improved treatment options. The pathophysiology of HF is complex and covers a spectrum of clinical presentations from HF with reduced ejection fraction (HFrEF) (≤40% EF) through to HF with preserved EF (HFpEF), with HFpEF patients demonstrating a reduced ability of the heart to relax despite an EF maintained above 50%. Prior to the last decade, the majority of clinical trials and animal models addressed HFrEF. Despite growing efforts recently to understand underlying mechanisms of HFpEF and find effective therapies for its treatment, clinical trials in patients with HFpEF have failed to demonstrate improvements in mortality. A significant obstacle to therapeutic innovation in HFpEF is the absence of preclinical models including large animal models which, unlike rodents, permit detailed instrumentation and extensive imaging and sampling protocols. Although several large animal models of HFpEF have been reported, none fulfil all the features present in human disease and few demonstrate progression to frank decompensated HF. This review summarizes well-established models of HFrEF in pigs, dogs and sheep and discusses attempts to date to model HFpEF in these species.

scholarly journals Approaches to Establish Extracardiac Total Cavopulmonary Connections in Animal Models—A Review

2019 ◽  
Vol 10 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Marcus Granegger ◽  
Anna Valencia ◽  
Daniel Quandt ◽  
Hitendu Dave ◽  
Oliver Kretschmar ◽  
...  
Keyword(s):  
Animal Models ◽  
Pulmonary Artery ◽  
Surgical Procedures ◽  
Full Text ◽  
Treatment Options ◽  
Main Pulmonary Artery ◽  
Large Animal ◽  
Venous Flow ◽  
Term Survival ◽  
Large Animal Models

Background: Long-term survival of patients with a single ventricle palliated with a Fontan procedure is still limited. No curative treatment options are available. To investigate the pathophysiology and potential treatment options, such as mechanical circulatory support (MCS), appropriate large animal models are required. The aim of this review was to analyze all full-text manuscripts presenting approaches for an extracardiac total cavopulmonary connection (TCPC) animal model to identify the feasibility and limitations in the acute and chronic setting. Methods: A literature search was performed for full-text publications presenting large animal models with extracardiac TCPCs on Pubmed and Embase. Out of 454 reviewed papers, 23 manuscripts fulfilled the inclusion criteria. Surgical procedures were categorized and hemodynamic changes at the transition from the biventricular to the univentricular condition analyzed. Results: Surgical procedures varied especially regarding coronary venous flow handling and anatomic shape of the TCPC. In most studies (n = 14), the main pulmonary artery was clamped and the coronary venous flow redirected by additional surgical interventions. Only in five reports, the caval veins were connected to the right pulmonary artery to create a true TCPC shape, whereas in all others (n = 18), the veins were connected to the main pulmonary artery. An elevated pulmonary vascular resistance was identified as a limiting hemodynamic factor for TCPC completion in healthy animals. Conclusions: A variety of acute TCPC animal models were successfully established with and without MCS, reflecting the most important hemodynamic features of a Fontan circulation; however, chronic animal models were not reported.

scholarly journals Minimally Invasive Sacroiliac Joint Fusion: One-Year Outcomes in 40 Patients

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Donald Sachs ◽  
Robyn Capobianco
Keyword(s):  
Joint Pain ◽  
Facet Joint ◽  
Treatment Options ◽  
Case Series ◽  
Effective Treatment Option ◽  
Trochanteric Bursitis ◽  
Joint Fusion ◽  
One Year ◽  
Si Joint ◽  
Implant System

Background. SI joint pain is difficult to diagnose due to overlapping symptoms of the lumbar spine, and until recently, treatment options have been limited. The purpose of this retrospective study is to report on the safety and effectiveness of MIS SI joint arthrodesis using a series of triangular, porous plasma coated implants in patients refractory to conservative care.Methods. We report on the first 40 consecutive patients with one-year follow-up data that underwent MIS SI joint fusion with the iFuse Implant System (SI-BONE, Inc., San Jose, CA) by a single surgeon. Medical charts were reviewed for demographics, perioperative metrics, complications, pain scores, and satisfaction.Results. Mean age was 58 years (range 30–81) and 75% of patients were female. Postoperative complications were minimal and included transient trochanteric bursitis (5%), facet joint pain (20%), and new low back pain (2.5%). There were no reoperations at one year. Mean pain score improved from 8.7 (1.5 SD) at baseline to 0.9 (1.6) at 12 months, a 7.8-point improvement (P<.001). Patient satisfaction was very high.Conclusions. The results of this case series reveal that MIS SI joint fusion using the iFuse Implant System is a safe and effective treatment option in carefully selected patients.

scholarly journals Tribological Aspects, Optimization and Analysis of Cu-B-CrC Composites Fabricated by Powder Metallurgy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4217
Author(s):  
Üsame Ali Usca ◽  
Mahir Uzun ◽  
Mustafa Kuntoğlu ◽  
Serhat Şap ◽  
Khaled Giasin ◽  
...  
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Applied Load ◽  
Practical Significance ◽  
Tribological Characteristics ◽  
M 10 ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Four Levels

Tribological properties of engineering components are a key issue due to their effect on the operational performance factors such as wear, surface characteristics, service life and in situ behavior. Thus, for better component quality, process parameters have major importance, especially for metal matrix composites (MMCs), which are a special class of materials used in a wide range of engineering applications including but not limited to structural, automotive and aeronautics. This paper deals with the tribological behavior of Cu-B-CrC composites (Cu-main matrix, B-CrC-reinforcement by 0, 2.5, 5 and 7.5 wt.%). The tribological characteristics investigated in this study are the coefficient of friction, wear rate and weight loss. For this purpose, four levels of sliding distance (1000, 1500, 2000 and 2500 m) and four levels of applied load (10, 15, 20 and 25 N) were used. In addition, two levels of sliding velocity (1 and 1.5 m/s), two levels of sintering time (1 and 2 h) and two sintering temperatures (1000 and 1050 °C) were used. Taguchi’s L16 orthogonal array was used to statistically analyze the aforementioned input parameters and to determine their best levels which give the desired values for the analyzed tribological characteristics. The results were analyzed by statistical analysis, optimization and 3D surface plots. Accordingly, it was determined that the most effective factor for wear rate, weight loss and friction coefficients is the contribution rate. According to signal-to-noise ratios, optimum solutions can be sorted as: the highest levels of parameters except for applied load and reinforcement ratio (2500 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 0 wt.%) for wear rate, certain levels of all parameters (1000 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 2.5 wt.%) for weight loss and 1000 m, 15 N, 1 m/s, 1 h, 1000 °C and 0 wt.% for the coefficient of friction. The comprehensive analysis of findings has practical significance and provides valuable information for a composite material from the production phase to the actual working conditions.

scholarly journals Molecular Mechanisms of Fetal Tendon Regeneration Versus Adult Fibrous Repair

2021 ◽  
Vol 22 (11) ◽  
pp. 5619
Author(s):  
Iris Ribitsch ◽  
Andrea Bileck ◽  
Alexander D. Aldoshin ◽  
Maciej M. Kańduła ◽  
Rupert L. Mayer ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Molecular Mechanisms ◽  
Unmet Need ◽  
Tendon Healing ◽  
Tendon Injury ◽  
Inflammatory Factors ◽  
Large Animal ◽  
Post Injury ◽  
Tendon Regeneration ◽  
Large Animal Models

Tendinopathies are painful, disabling conditions that afflict 25% of the adult human population. Filling an unmet need for realistic large-animal models, we here present an ovine model of tendon injury for the comparative study of adult scarring repair and fetal regeneration. Complete regeneration of the fetal tendon within 28 days is demonstrated, while adult tendon defects remained macroscopically and histologically evident five months post-injury. In addition to a comprehensive histological assessment, proteome analyses of secretomes were performed. Confirming histological data, a specific and pronounced inflammation accompanied by activation of neutrophils in adult tendon defects was observed, corroborated by the significant up-regulation of pro-inflammatory factors, neutrophil attracting chemokines, the release of potentially tissue-damaging antimicrobial and extracellular matrix-degrading enzymes, and a response to oxidative stress. In contrast, secreted proteins of injured fetal tendons included proteins initiating the resolution of inflammation or promoting functional extracellular matrix production. These results demonstrate the power and relevance of our novel ovine fetal tendon regeneration model, which thus promises to accelerate research in the field. First insights from the model already support our molecular understanding of successful fetal tendon healing processes and may guide improved therapeutic strategies.

scholarly journals Hyperinsulinaemic hypoglycaemia in non-anaesthetized Göttingen minipigs induces a counter-regulatory endocrine response and electrocardiographic changes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mille K. Lyhne ◽  
Andreas Vegge ◽  
Gro Klitgaard Povlsen ◽  
Rita Slaaby ◽  
Jonas Kildegaard ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Fold Increase ◽  
Diabetic Group ◽  
Large Animal ◽  
Qtc Interval ◽  
Interval Prolongation ◽  
Hyperinsulinaemic Hypoglycaemia ◽  
Large Animal Models ◽  
Qtc Interval Prolongation ◽  
Electrocardiographic Recordings

AbstractThe potentially fatal cardiovascular effects of hypoglycaemia are not well understood and large animal models of the counter-regulatory responses and cardiovascular consequences of insulin-induced hypoglycaemia are needed to understand the mechanisms in humans. The aim of this study was to develop a human-like minipig model of hypoglycaemia including healthy and diabetic pigs to investigate endocrine, electrocardiographic and platelet effects. Hypoglycaemia was induced using a hyperinsulinaemic, hypoglycaemic clamp and an insulin bolus protocol. Plasma glucose, glucagon, C-peptide, insulin, epinephrine and platelet aggregation responses were measured before, during and after hypoglycaemia. Continuous electrocardiographic recordings were obtained. Hypoglycaemia at a plasma glucose concentration of 0.8–1.0 mM in the clamp induced 25-fold increase in epinephrine and sixfold and threefold increase in glucagon for healthy and diabetic pigs, respectively. The hypoglycaemic clamp induced QTc-interval prolongation and increase in cardiac arrhythmias. In the bolus approach, the non-diabetic group reached plasma glucose target of 1.5 mM and QTc-interval was prolonged after insulin injection, but before glucose nadir. The diabetic group did not reach hypoglycaemic target, but still demonstrated QTc-interval prolongation. These results demonstrate effects of hyperinsulinaemic hypoglycaemia closely resembling human physiology, indicating the minipig as a translational animal model of counter-regulatory endocrine and myocardial effects of hypoglycaemia.

scholarly journals Large Animal Models for Investigating Cell Therapies of Stress Urinary Incontinence

2021 ◽  
Vol 22 (11) ◽  
pp. 6092
Author(s):  
Bastian Amend ◽  
Niklas Harland ◽  
Jasmin Knoll ◽  
Arnulf Stenzl ◽  
Wilhelm K. Aicher
Keyword(s):  
Urinary Incontinence ◽  
Stress Urinary Incontinence ◽  
Animal Models ◽  
Clinical Situation ◽  
Surgical Instruments ◽  
Health Concern ◽  
Large Animal ◽  
Knock Out ◽  
Cell Therapies ◽  
Large Animal Models

Stress urinary incontinence (SUI) is a significant health concern for patients affected, impacting their quality of life severely. To investigate mechanisms contributing to SUI different animal models were developed. Incontinence was induced under defined conditions to explore the pathomechanisms involved, spontaneous recovery, or efficacy of therapies over time. The animal models were coined to mimic known SUI risk factors such as childbirth or surgical injury. However, animal models neither reflect the human situation completely nor the multiple mechanisms that ultimately contribute to the pathogenesis of SUI. In the past, most SUI animal studies took advantage of rodents or rabbits. Recent models present for instance transgenic rats developing severe obesity, to investigate metabolic interrelations between the disorder and incontinence. Using recombinant gene technologies, such as transgenic, gene knock-out or CRISPR-Cas animals may narrow the gap between the model and the clinical situation of patients. However, to investigate surgical regimens or cell therapies to improve or even cure SUI, large animal models such as pig, goat, dog and others provide several advantages. Among them, standard surgical instruments can be employed for minimally invasive transurethral diagnoses and therapies. We, therefore, focus in this review on large animal models of SUI.

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