Interrater reproducibility of the Myoton and durometer devices to quantify sclerotic chronic graft-versus-host disease

Pediatric Transplant and Cellular Therapy Consortium RESILIENT Conference on Pediatric Chronic Graft-Versus-Host Disease Survivorship After Hematopoietic Cell Transplantation: Part I. Phases of Chronic GVHD, Supportive Care, and Systemic Therapy Discontinuation

Current literature lacks details on the impact of pediatric chronic graft-versus-host disease (cGVHD) on long-term survivorship after allogeneic hematopoietic cell transplantation (HCT). Nonetheless, cGVHD remains a leading cause of post-transplant morbidity and mortality in children and adolescents, which is particularly relevant given the longer life-expectancy after HCT (measured in decades) compared to older adults. To address this knowledge gap, leaders of the Pediatric Transplant and Cellular Therapy Consortium convened a multidisciplinary taskforce of experts in pediatric cGVHD and HCT late effects known as RESILIENT after Chronic GVHD (Research and Education towards Solutions for Late effects to Innovate, Excel, and Nurture after cGVHD). Our goals were to define: (1) the current state of understanding about how cGVHD impacts long-term survivorship in children transplanted <18 yr of age; (2) practical aspects of care to help clinicians managing long-term pediatric cGVHD survivors; and (3) develop a research framework for the next decade to further our knowledge. Four working groups were formed, each tasked with addressing a unique theme: (1) cGVHD natural history (phases of cGVHD) and its impact on clinicians' ability to taper and durably discontinue systemic therapy; (2) organ dysfunction and immune reconstitution in relation to survivorship; (3) how cGVHD and its treatment impact growth, metabolism, and development in children; and (4) psychosocial health and patient reported outcomes. The 4 groups met before the 2024 BMT Tandem Meeting in San Antonio, Texas, and then convened a larger in-person RESILIENT conference held on February 20, 2024, at the Tandem meeting to put forth recommendations from their respective working groups and garner feedback. These recommendations are now presented in a series of 4 manuscripts. This current manuscript focuses on the first theme and discusses the phases of cGVHD, challenges in differentiating clinically active from quiescent cGVHD in clinical practice, and the resultant difficulties in determining when and if to taper systemic therapy. To overcome these challenges, we propose revised categorization of long-term cGVHD outcomes and practical recommendations for clinicians and researchers around the long-term follow-up for these patients, including determining when and if to taper systemic therapy, along with the integration of non-immunosuppressive supportive care interventions.

mTG-Gelatin phantoms as standardized testbeds for skin biomechanical measurements with Myoton

Quantitative assessment of skin mechanical properties can play a pivotal role in diagnosing and tracking various dermatological conditions. Myoton is a promising tool that rapidly and noninvasively measures five skin biomechanical parameters. Accurate interpretation of these parameters requires systematic in vitro testing with easy-to-fabricate, cost-effective skin-mimicking phantoms with controllable properties. In this study, we assessed the ability of phantoms made with 5% and 10% gelatin crosslinked with microbial transglutaminase (mTG) to mimic the human skin for Myoton measurements. We discovered that each of the five Myoton parameters displayed moderate to high correlations with shear elastic modulus of the phantoms. Furthermore, Myoton effectively tracked changes in the mechanical properties of these models over time. Additionally, we designed bilayer phantoms incorporating both dermis and subcutaneous tissue-mimicking layers. Myoton successfully distinguished changes in the mechanical properties of the bilayer phantoms due to the introduction of a stiff 2 mm top layer. We also found that 5% mTG-gelatin phantoms mimic Myoton measurements from healthy subjects and 10% phantoms mimic patients with sclerotic chronic graft-versus-host disease (cGVHD). Therefore, multi-layered mTG-gelatin models for skin and soft tissues can serve as standardized testbeds to study different sclerotic skin conditions in a systematic manner.

Comparison of treatment response measures in cutaneous sclerosis after allogeneic hematopoietic cell transplantation

ABSTRACT

Cutaneous sclerosis, a highly morbid subtype of chronic graft-versus-host disease (GVHD), demonstrates limited treatment response under current National Institutes of Health (NIH) response measures. We explored novel sclerosis-specific response measures using Chronic GVHD Consortium data. A training cohort included patients with cutaneous sclerosis from a randomized trial of imatinib vs rituximab and a consortium observational study. The validation cohort was a different consortium observational study. Clinician-reported measures (baseline and baseline to 6-month change) were examined for association with 6-month clinician-reported response. Patient-reported measures (baseline and baseline to 6-month change) were studied for association with 6-month patient-reported response. A total of 347 patients were included (training 183 and validation 164). Although multiple skin and joint measures were associated with clinician-reported response on univariate analysis, patient range of motion (PROM) total score, PROM total score change, and NIH 0 to 3 skin change were retained in the final multivariate model (area under the receiver operating characteristic curve [AUC], 0.83 training and 0.75 validation). Similarly, many patient-reported measures were associated, but final multivariate analysis retained the human activity profile adjusted activity score (AAS), 36 item short form health survey (SF36) vitality change, Lee symptom scale (LSS) skin, and LSS skin change in the model (AUC, 0.86 training and 0.75 validation). We identified which sclerosis measures have the greatest association with 6-month clinician- and patient-reported treatment responses, a previously unstudied area. However, given the observed performance in the validation cohorts, we conclude that further work is needed. Novel response measures may be needed to optimally assess treatment response in cutaneous sclerosis.

Reliability of MyotonPro in measuring the biomechanical properties of the quadriceps femoris muscle in people with different levels and types of motor preparation

The aim of this research was to evaluate the reliability of the measurements of biomechanical parameters of the muscles of athletes representing different disciplines as well as untrained people. Ninety-four young, healthy male individuals participated in the study and were divided into five subgroups: footballers (n = 25), volleyballers (n = 14), handballers (n = 19), MMA fighters (n = 16), and undrained group (n = 20). All of the participants underwent measurements of stiffness (S), muscle tone (T) and elasticity (E) by two independent measurers using MyotonPro equipment. Analysis was conducted on two different parts of the quadriceps femoris: rectus femoris (RF) and vastus medialis (VM. Consequently, the comprehensive analysis comprised 564 measurements (94 participants * 3 parameters = 282 * 2 measurers = 564). The results proves high reliability of the myotonometry (Pearson's CC over 0.8208-0.8871 for different parameters, ICC from to 0.74 to 0.99 for different muscles and parameters) excluding only stiffness for the VM which was characterized withlow ICC of 0.08 and relatively highest between the examined parameters MAE% of 8.7% which still remains low value. The most significant differences between the parameters in examined groups were observed between MMA fighters and volleyballers in terms of muscle tone and elasticity of the VM (correlation of 0.14842 and 0.15083 respecitively). These results confirm the usability of myotonometry in measuring the biomechanical properties of the muscles in different sports groups and confirm the independence of the results obtained from the person performing the measurement.

Performance of myotonometer in the assessment of skin involvement in systemic sclerosis

OBJECTIVES

A clinically practical tool to assess skin biomechanical properties rapidly and accurately is still lacking. Our aim was to examine the intra- and inter-observer reproducibility of a myotonometer for objective skin property assessment in systemic sclerosis (SSc), comparing it with the modified Rodnan skin score (mRSS), and distinguishing patients from healthy controls.

METHOD

Thirty-four patients (21 limited and 13 diffuse SSc), and 31 age and gender-matched healthy controls were enrolled. Skin tone and stiffness were measured at four different anatomical sites (the forearm, hand, leg, and foot) using a myotonometer. The correlation between the mRSS and skin properties was assessed. Also, hand functionality was evaluated for possible correlations between the variables. The differences in skin properties between dcSSc and lcSSc patients, and healthy controls were assessed using variance analysis.

RESULTS

Intra- and inter-examiner reproducibility were excellent (ICC = 0.70 to 0.98) for tone and stiffness except for non-dominant hand tone, which showed good reliability (ICC = 0.64 to 0.74). Stiffness and tone values of the hands, forearms, and feet significantly correlated with mRSS total score (r = 0.40 to 0.71, p < 0.05). Additionally, tone and stiffness of the hands and forearms moderately correlated with hand function (p < 0.05). Tone and stiffness values increased in patients with dcSSc compared to healthy controls, or patients with lcSSc, at the hands, forearms, and legs (p < 0.05).

CONCLUSIONS

Our findings emphasize the potential utility of the myotonometer for assessing skin properties and differentiating SSc patients from controls, demonstrating its promise as a valuable clinical evaluation tool in this context. Key Points •The myotonometer displayed excellent intra- and inter-examiner reproducibility for assessing skin properties. •Skin tone and stiffness parameters well correlated with the mRSS scores. •The myotonometer can distinguish patients with diffuse cutaneous SSc from healthy controls.