Patients with Intolerance Reactions to Total Knee Replacement: Combined Assessment of Allergy Diagnostics, Periprosthetic Histology, and Peri-implant Cytokine Expression Pattern

We performed a combined approach to identify suspected allergy to knee arthroplasty (TKR): patch test (PT), lymphocyte transformation test (LTT), histopathology (overall grading; T- and B-lymphocytes, macrophages, and neutrophils), and semiquantitative Real-time-PCR-based periprosthetic inflammatory mediator analysis (IFN gamma, TNF alpha, IL1-beta, IL-2, IL-6, IL-8, IL-10, IL17, and TGF beta). We analyzed 25 TKR patients with yet unexplained complications like pain, effusion, and reduced range of motion. They consisted of 20 patients with proven metal sensitization (11 with PT reactions;9 with only LTT reactivity). Control specimens were from 5 complicated TKR patients without metal sensitization, 12 OA patients before arthroplasty, and 8 PT patients without arthroplasty. Lymphocytic infiltrates were seen and fibrotic (Type IV membrane) tissue response was most frequent in the metal sensitive patients, for example, in 81% of the PT positive patients. The latter also had marked periprosthetic IFN gamma expression. 8/9 patients with revision surgery using Ti-coated/oxinium based implants reported symptom relief. Our findings demonstrate that combining allergy diagnostics with histopathology and periprosthetic cytokine assessment could allow us to design better diagnostic strategies

The Role of 1.5 Tesla MRI and Anesthetic Regimen Concerning Cardiac Analysis in Mice with Cardiomyopathy

Accurate assessment of left ventricular function in rodent models is essential for the evaluation of new therapeutic approaches for cardiac diseases. In our study, we provide new insights regarding the role of a 1.5 Tesla (T) magnetic resonance imaging (MRI) device and different anesthetic regimens on data validity. As dedicated small animal MRI and echocardiographic devices are not broadly available, we evaluated whether monitoring cardiac function in small rodents with a clinical 1.5 T MRI device is feasible. On a clinical electrocardiogram (ECG) synchronized 1.5 T MRI scanner we therefore studied cardiac function parameters of mice with chronic virus-induced cardiomyopathy. Thus, reduced left ventricular ejection fraction (LVEF) could be verified compared to healthy controls. However, our results showed a high variability. First, anesthesia with medetomidine, midazolam and fentanyl (MMF) led to depressed cardiac function parameters and more variability than isoflurane gas inhalation anesthesia, especially at high concentrations. Furthermore, calculation of an average ejection fraction value from sequenced scans significantly reduced the variance of the results. To sum up, we introduce the clinical 1.5 T MRI device as a new tool for effective analysis of left ventricular function in mice with cardiomyopathy. Besides, we suggest isoflurane gas inhalation anesthesia at high concentrations for variance reduction and recommend calculation of an average ejection fraction value from multiple sequenced MRI scans to provide valid data and a solid basis for further clinical testing

Patients with Intolerance Reactions to Total Knee Replacement: Combined Assessment of Allergy Diagnostics, Periprosthetic Histology, and Peri-implant Cytokine Expression Pattern

We performed a combined approach to identify suspected allergy to knee arthroplasty (TKR): patch test (PT), lymphocyte transformation test (LTT), histopathology (overall grading; T- and B-lymphocytes, macrophages, and neutrophils), and semiquantitative Real-time-PCR-based periprosthetic inflammatory mediator analysis (IFNγ, TNFα, IL1-β, IL-2, IL-6, IL-8, IL-10, IL17, and TGFβ). We analyzed 25 TKR patients with yet unexplained complications like pain, effusion, and reduced range of motion. They consisted of 20 patients with proven metal sensitization (11 with PT reactions; 9 with only LTT reactivity). Control specimens were from 5 complicated TKR patients without metal sensitization, 12 OA patients before arthroplasty, and 8 PT patients without arthroplasty. Lymphocytic infiltrates were seen and fibrotic (Type IV membrane) tissue response was most frequent in the metal sensitive patients, for example, in 81% of the PT positive patients. The latter also had marked periprosthetic IFNγ expression. 8/9 patients with revision surgery using Ti-coated/oxinium based implants reported symptom relief. Our findings demonstrate that combining allergy diagnostics with histopathology and periprosthetic cytokine assessment could allow us to design better diagnostic strategies

Echocardiography confirms values obtained by MRI.

<p>A) Echocardiography was able to reproduce the low LVEF values we obtained from MMF anesthetized mice investigated by MRI. B) Heart rates (HR) and C) cardiac output (CO) measured by our Vevo2100 system did not significantly differ from those in the MRI study. D) Anesthesia with isoflurane revealed the cardiodepressive effects of MMF. n.s.: not significant; **: p<0.01; ***: p<0.001.</p

Anesthesia with isoflurane reduces variability of data.

<p>Compared to MMF, isoflurane is able to reduce the variability of the results. Additionally, isoflurane at higher concentrations than commonly used might further reduce the variability of heart rate and heart rate dependent values such as cardiac output and cardiac index. However, compared with lower isoflurane concentrations (1.75%), high isoflurane concentrations (3%) show no significant cardiodepressive effects. A) Shows percentual standard deviations of single cycle values, and B) of mean values (average of 3 consecutive cycles). (C) Shows percentual standard deviations for cardiac output and cardiac index obtained with either MMF, 1.75% isoflurane or 3% isoflurane. D) Shows heart rate, E) cardiac output and F) cardiac index under different anesthetic regimens. EF = LVEF, EDV = end diastolic volume, ESV = end systolic volume, SV = stroke volume, HR = heart rate, CO = cardiac output, CI = cardiac index. 100 µl MMF: n = 6, 1.75% isoflurane and 3% isoflurane: n = 7. ***: p<0.001.</p

Left ventricular function parameters in healthy mice under different anesthetic regimen.

<p><i>1.75% = anesthesia with 1.75% isoflurane; 3% = 3% isoflurane. MMF = 100 µl MMF injected i.p. for maintenance of anesthesia. RR = relative reduction comparing MMF and 1.75% isoflurane and MMF and 3% isoflurane. Values are presented as mean, along with the corresponding p values (Student's t test).</i></p><p><i>*: p<0.05,</i></p><p><i>**: p<0.01,</i></p><p><i>***: p<0.001.</i></p><p><i>No statistical differences were observed between the 1.75% group and the 3% group.</i></p

Calculation of an average LVEF value reduces variability of data independently from the anesthetic regimen.

<p>For evaluation of cardiac function parameters, 3 consecutive cycles were measured and averaged. Mean values showed a reduced variability compared to values obtained by single cycle measurements. A) Shows single cycle and mean values for the group anesthetized with 1.75% isoflurane, B) for the group anesthetized with 3% isoflurane and C) for the group anesthetized with 100 µl MMF. EF = LVEF, EDV = end diastolic volume, ESV = end systolic volume, SV = stroke volume, HR = heart rate, CO = cardiac output, CI = cardiac index. 100 µl MMF: n = 6, 1.75% isoflurane and 3% isoflurane: n = 7.</p

Comparison of MRI devices and results on cardiac function in small animals and in humans.

#<p><i> = LVEF evaluation in human populations;</i></p><p><i>y = yes, n = no; SD = standard deviation;</i></p><p><i>* = mean relative SD in % of LVEF of the control group only.</i></p