A novel murine model of pulmonary fibrosis: the role of platelets in chronic changes induced by bleomycin

Idiopathic pulmonary fibrosis (IPF) is a disease that causes scarring and destruction of lung tissue that is ultimately fatal. There is a need to develop improved treatments for IPF. One problem with identifying novel treatments of IPF is the poor predictability of current preclinical models. Few model investigate lung function changes, rather relying on histological changes which doesn't adequately reflect the complete clinical situation. The aim of this study was to establish a novel model of pulmonary fibrosis where we could investigate changes in lung function, and histology. We have also utilised this model to investigate the role of platelets in pulmonary fibrosis as platelets have been recognised as having a broader role than just facilitating haemostasis. Lung fibrosis was induced in male C57BL6/J mice by intranasal bleomycin on Days 0, 1, 2, 5, 6 and 7. Platelets were depleted by twice-weekly administration of anti-platelet antibodies. On Day 35 mice were assessed by examining lung function, platelet infiltration into lung tissues and bronchoalveolar lavage fluid (BAL), levels of BAL Tissue growth factor (TGF)-β levels, and the degree of fibrosis evaluated histologically. Repeated bleomycin administration caused loss of lung function associated with fibrosis assessed histologically. Platelet depletion resulted in a reduction in fibrosis and modest inhibition of lung function changes. We have established a novel model of pulmonary fibrosis that is associated with a decline in lung function similar to the clinical setting. Furthermore, platelet depletion resulted in a less severe fibrosis suggesting that targeting platelets maybe worth further investigation.

Investigation and management of prosthetic joint infection in knee replacement: A BASK Surgical Practice Guideline

BACKGROUND

The burden of knee replacement prosthetic joint infection (KR PJI) is increasing. KR PJI is difficult to treat, outcomes can be poor and it is financially expensive and limited evidence is available to guide treatment decisions.

AIM

To provide guidelines for surgeons and units treating KR PJI.

METHODS

Guideline formation by consensus process undertaken by BASK's Revision Knee Working Group, supported by outputs from UK-PJI meetings.

RESULTS

Improved outcomes should be achieved through provision of care by revision centres in a network model. Treatment of KR PJI should only be undertaken at specialist units with the required infrastructure and a regular infection MDT. This document outlines practice guidelines for units providing a KR PJI service and sets out: CONCLUSIONS: KR PJI patients treated within the NHS should be provided the best care possible. This report sets out guidance and support for surgeons and units to achieve this.

A correlation between the timing of biopsy after autologous chondrocyte implantation and the histological appearance

Autologous chondrocyte implantation is an option in the treatment of full-thickness chondral or osteochondral injuries which are symptomatic. The goal of surgery and rehabilitation is the replacement of damaged cartilage with hyaline or hyaline-like cartilage, producing improved levels of function and preventing early osteoarthritis. The intermediate results have been promising in terms of functional and clinical improvement.

Our aim was to explore the hypothesis that the histological quality of the repair tissue formed after autologous chondrocyte implantation improved with increasing time after implantation.

In all, 248 patients who had undergone autologous chondrocyte implantation had biopsies taken of the repair tissue which then underwent histological grading. Statistical analysis suggested that with doubling of the time after implantation the likelihood of a favourable histological outcome was increased by more than fourfold (p < 0.001).

Chromosomal aberrations in the peripheral blood of patients with metal-on-metal hip bearings

BACKGROUND

Approximately one-third of patients undergoing joint replacement are under sixty years of age. Many of these patients may be exposed to wear debris from the orthopaedic implant for several decades. Clinical follow-up of this group of patients has been short compared with the lifetimes of the patients, and the long-term effects of this chronic exposure are unknown.

METHODS

By using cytogenetic biomarkers (twenty-four-color fluorescent in situ hybridization [FISH]), we analyzed the peripheral blood leukocytes for chromosomal aberrations in three groups of subjects: (1) six age and sex-matched control subjects who had no implant and did not smoke (control group), (2) five subjects in whom an implant with a metal-on-metal articulation had been in situ for an average of thirty-five years (metal-on-metal group), and (3) four subjects in whom a metal-on-metal implant had been revised to a metal-on-polyethylene articulation at an average of twenty-two years (revised group).

RESULTS

The number of chromosomal aberrations in the metal-on-metal group was greater than that in the control group. Specifically, the percentage of aneuploidy gain was three times greater (p = 0.01) in the metal-on-metal group. Structural aberrations were not seen in the control group, and this difference was highly significant (p = 0.003). Also, the number of chromosomal aberrations in the metal-on-metal group was greater than that in the revised group. Specifically, the percentage of structural aberrations was thirty-one-fold higher (p = 0.013). The percentage of aneuploidy gain in the metal-on-metal group was about twice that in the revised group, although this difference was not significant (p = 0.37). The percentage of aneuploidy gain in the revised group was about double that in the control group, although this difference was also not significant (p = 0.41). Translocations were seen only in subjects with a metal-on-metal articulation.

CONCLUSIONS

The clinical consequences of the chromosomal changes seen in this study are unknown, and it is unknown if the changes are present in other cells in the body. The results emphasize the need for additional investigations into the effect of chronic exposure to elevated levels of metal ions produced by orthopaedic implants.

A prospective, randomised study comparing two techniques of autologous chondrocyte implantation for osteochondral defects in the knee: Periosteum covered versus type I/III collagen covered

INTRODUCTION

The results for autologous chondrocyte implantation (ACI) in the treatment of full thickness chondral defects in the knee are encouraging. At present two techniques have been described to retain the chondrocyte suspension within the defect. The first involves using a periosteal cover (ACI-P) and the second involves using a type I/III collagen membrane (ACI-C). To the authors knowledge there are no comparative studies of these two techniques in the current literature. We have therefore undertaken such a study to establish if there is a difference between the 2 techniques based on a clinical and arthroscopic assessment.

METHODS

A total of 68 patients with a mean age of 30.52 years with symptomatic articular cartilage defects were randomised to have either ACI-P (33 patients) or ACI-C (35 patients). The mean defect size was 4.54 cm2. All patients were followed up at 24 months.

RESULTS

A clinical and functional assessment showed that 74% of patients had a good or excellent result following the ACI-C compared with 67% after the ACI-P at 2 years. Arthroscopy at 1 year also demonstrated similar results for both techniques. However, 36.4% of the ACI-P grafts required shaving for hypertrophy compared with none for the ACI-C grafts at 1 year.

DISCUSSION

This study has shown no statistical difference between the clinical outcome of ACI-C versus ACI-P at 2 years. A significant number of patients who had the ACI-P required shaving of a hypertrophied graft. We conclude that there is no advantage in using periosteum as a cover for retaining chondrocytes within an osteochondral defect; as a result we advocate the use of an alternative cover such as a manufactured type I/III collagen membrane.

Ventricular remodeling after cardiomyoplasty in heart failure sheep: passive and dynamic effects

BACKGROUND

Recent reports claim that cardiomyoplasty (CMP) has a girdling effect on the left ventricle, to prevent dilatation and functional deterioration, but the mechanism of its long-term effects on the native heart is not known. We compared the relative role of CMP's active squeezing and passive girdling in chronically failing hearts.

METHODS

After induction of stable heart failure (left ventricular ejection fraction = 27% +/- 7%) by staged coronary microembolization, CMP was performed in 11 of 18 sheep. After 8 weeks pacing training of the latissimus dorsi muscle (LDM), cardiac assist was begun with 1:2 synchronous bursts in 6 sheep (d-CMP, n = 6), and the LDM in the passive group (p-CMP, n = 5) remained unstimulated. Four (base line) and 30 weeks after induction of heart failure, the pressure-volume relationship was derived.

RESULTS

After 30 weeks in d-CMP the slope (Emax) of the end-systolic pressure-volume relationship increased by 66% +/- 55% (p < 0.05) and external work efficiency by 48% +/- 41% (p < 0.01). In the passive CMP and control groups, slope and external work efficiency were unchanged. Conversely, left ventricular end-diastolic volume decreased (-14% +/- 12%, p < 0.05) in the dynamic CMP group compared with a static course in the passive CMP group (3% +/- 10%, p > 0.05) and an increase (18% +/- 15%, p < 0.05) in controls.

CONCLUSIONS

Dynamic CMP improved native heart's contractility and external work efficiency. In addition, whereas passive CMP has simply a girdling effect, dynamic CMP also induces reverse left ventricular chamber remodeling.

In situ measurements of skeletal muscle power output using new capacitive strain gauge

Experiments are described in which a fatigue index is determined for the latissimus dorsi muscle of sheep in situ, using capacitive strain gauges. Parallel experiments for invasive and non-invasive measurements are conducted, measuring global contraction and relaxation rates and shortening duration for paced muscle. The results show that, above one pulse per burst (5 V, 100 microseconds pulsewidth), contraction rates (62 +/- 11 mm s-1) and relaxation rates (50 +/- 7 mm s-1) are constant for unloaded muscle. For one animal, fatigue testing with a 2.5 kg load at six pulses per burst shows shortening rates increasing to a maximum (80 mm s-1) after 30 s and reducing to 5 mm s-1 after 150 s. The decrease in shortening amplitude is used as a fatigue index, log displacement against time. Power output is load dependent, measuring 4.7 W kg-1 with a 2.5 kg load. There is good agreement between the invasive and non-invasive measurements, thus providing a method for monitoring changes in muscle parameters non-invasively during future pacing transformation.