[Perceived utility of the inclusion of physician assistants in the surgical process quality and continuing education in Germany : Results of an interprofessional online survey]. / Empfundener Nutzen der Einbindung von Physician Assistants in die chirurgische Prozessqualität und Weiterbildung in Deutschland : Ergebnisse einer interprofessionellen Online-Umfrage.

BACKGROUND: Compared to Anglo-American countries, physician assistants (PA) remain an underrepresented professional group within the German healthcare system. In the surgical disciplines, PAs may relieve the administrative burden of doctors by taking on delegable routine tasks, thus creating time and resources for advanced surgical training. OBJECTIVE: According to interprofessional experts, can the use of PA lead to an optimization of surgical training and a gain in time for surgical qualification in Germany? MATERIAL AND METHODS: After searching for systematic reviews of the current state of knowledge, an online survey was initiated among surgeons and PAs via social networks to determine current and desired clinical areas of activity for PAs in surgery and their future influence on specialist training in Germany. RESULTS: A total of nine systematic reviews were identified, suggesting a beneficial impact of PAs on length of stay, direct costs, and treatment outcomes in surgical scenarios. The online survey included 234 surgeons and 114 PAs. Hospitals with ≥ 90 surgical beds employed PAs far more frequently (65%) than smaller institutions (40%). Although both professional groups are generally highly satisfied with the integration of PAs into clinical workflows, there are gradually different opinions about the preferred spectrum of tasks and duties. DISCUSSION: PAs would like to have greater responsibility in ordering and interpreting diagnostic tests, communicating with patients, and working in the operating theater. Surgeons are concerned that PAs could replace surgical interns and residents. PAs may enrich healthcare in Germany on various levels and can also improve surgical training. The voice and needs of all professional groups must be considered and respected during the upcoming health system reform.

Receptor transfer between immune cells by autoantibody-enhanced, CD32-driven trogocytosis is hijacked by HIV-1 to infect resting CD4 T cells.

Immune cell phenotyping frequently detects lineage-unrelated receptors. Here, we report that surface receptors can be transferred from primary macrophages to CD4 T cells and identify the Fcγ receptor CD32 as driver and cargo of this trogocytotic transfer. Filamentous CD32+ nanoprotrusions deposit distinct plasma membrane patches onto target T cells. Transferred receptors confer cell migration and adhesion properties, and macrophage-derived membrane patches render resting CD4 T cells susceptible to infection by serving as hotspots for HIV-1 binding. Antibodies that recognize T cell epitopes enhance CD32-mediated trogocytosis. Such autoreactive anti-HIV-1 envelope antibodies can be found in the blood of HIV-1 patients and, consistently, the percentage of CD32+ CD4 T cells is increased in their blood. This CD32-mediated, antigen-independent cell communication mode transiently expands the receptor repertoire and functionality of immune cells. HIV-1 hijacks this mechanism by triggering the generation of trogocytosis-promoting autoantibodies to gain access to immune cells critical to its persistence.

Effect of an interdisciplinary inpatient program for patients with CRPS in reducing disease activity -a single center prospective cohort study.

OBJECTIVE: The aim of this study was to evaluate the benefit of inpatient treatment in reducing disease activity in patients with CRPS who have exhausted outpatient options. Furthermore, the study sought to identify patient-related outcome variables that predict a reduction in disease activity. METHODS: The primary outcome was disease severity (CRPS Severity Score, range 0-16 points)). Secondary outcomes included depression, anxiety, physical function, pain interference, fatigue, sleep disturbance, and ability to participate in social roles and activities, all of which were assessed using the Promis-29. Furthermore, pain catastrophizing, neuropathic pain, quality of life, pain self-efficacy, medication intake, and the patient's global impression of change were examined in accordance with current international agreed recommendations, assessed at discharge, three-month and six-month post-discharge. Mixed-effects models were conducted to identify baseline variables associated with CRPS severity. RESULTS: Twenty-five patients completed the program (mean age 49.28 (SD 11.23) years, 92% females, mean symptom duration 8.5 (SD 6.5) months). Results showed a significant reduction between baseline and discharge of disease activity (CSS -2.36, p < 0.0001), pain (PROMIS-29 pain -0.88, p = 0.005) and emotional function (PROMIS-29 depression -5.05, p < 0.001; fatigue -4.63, p = 0.002). Moderate evidence for a reduction between baseline and discharge could be observed for pain interference (+2.27, p = 0.05), social participation (PROMIS-29 +1.93, p = 0.05), anxiety (PROMIS-29 -3.32, p = 0.02) and physical function (PROMIS-29 +1.3, p = 0.03). On discharge, 92% of patients (23 of 25) reported improvement in their overall condition. In the follow-up period, medication intake could be reduced after 3 (MQS -8.22, p = 0.002) and 6 months (MQS -8.69, p = 0.001), and there was further improvement in social participation after 3 months (PROMIS-29 +1.72, 0.03) and sleep after 6 months (PROMIS-29 +2.38, 0.008). In the mixed models, it was demonstrated that patients experiencing less pain at baseline also exhibited lower disease activity. CONCLUSION: The results of this study confirm that inpatient interdisciplinary treatment of CRPS patients improves disease activity, pain, physical function, emotional function, and social participation. Most improvements were maintained for up six months after discharge. The majority of patients reported that their overall condition had improved during the study period.

Epigenetic Priming Enhances Chondrogenic Potential of Expanded Chondrocytes.

Expansion of chondrocytes presents a major obstacle in the cartilage regeneration procedure, such as matrix-induced autologous chondrocyte implantation. Dedifferentiation of chondrocytes during the expansion process leads to the emergence of a fibrotic (chondrofibrotic) phenotype that decreases the chondrogenic potential of the implanted cells. We aim to (1) determine the extent that chromatin architecture of H3K27me3 and H3K9me3 remodels during dedifferentiation and persists after the transfer to a three-dimensional (3D) culture; and (2) to prevent this persistent remodeling to enhance the chondrogenic potential of expanded bovine chondrocytes, used as a model system. Chromatin architecture remodeling of H3K27me3 and H3K9me3 was observed at 0 population doublings, 8 population doublings, and 16 population doublings (PD16) in a two-dimensional (2D) culture and after encapsulation of the expanded chondrocytes in a 3D hydrogel culture. Chondrocytes were treated with inhibitors of epigenetic modifiers (epigenetic priming) for PD16 and then encapsulated in 3D hydrogels. Chromatin architecture of chondrocytes and gene expression were evaluated before and after encapsulation. We observed a change in chromatin architecture of epigenetic modifications H3K27me3 and H3K9me3 during chondrocyte dedifferentiation. Although inhibiting enzymes that modify H3K27me3 and H3K9me3 did not alter the dedifferentiation process in 2D culture, applying these treatments during the 2D expansion did increase the expression of select chondrogenic genes and protein deposition of type II collagen when transferred to a 3D environment. Overall, we found that epigenetic priming of expanded bovine chondrocytes alters the cell fate when chondrocytes are later encapsulated into a 3D environment, providing a potential method to enhance the success of cartilage regeneration procedures.

Sex-associated differences in frequencies and prognostic impact of recurrent genetic alterations in adult acute myeloid leukemia (Alliance, AMLCG).

Clinical outcome of patients with acute myeloid leukemia (AML) is associated with demographic and genetic features. Although the associations of acquired genetic alterations with patients' sex have been recently analyzed, their impact on outcome of female and male patients has not yet been comprehensively assessed. We performed mutational profiling, cytogenetic and outcome analyses in 1726 adults with AML (749 female and 977 male) treated on frontline Alliance for Clinical Trials in Oncology protocols. A validation cohort comprised 465 women and 489 men treated on frontline protocols of the German AML Cooperative Group. Compared with men, women more often had normal karyotype, FLT3-ITD, DNMT3A, NPM1 and WT1 mutations and less often complex karyotype, ASXL1, SRSF2, U2AF1, RUNX1, or KIT mutations. More women were in the 2022 European LeukemiaNet intermediate-risk group and more men in adverse-risk group. We found sex differences in co-occurring mutation patterns and prognostic impact of select genetic alterations. The mutation-associated splicing events and gene-expression profiles also differed between sexes. In patients aged <60 years, SF3B1 mutations were male-specific adverse outcome prognosticators. We conclude that sex differences in AML-associated genetic alterations and mutation-specific differential splicing events highlight the importance of patients' sex in analyses of AML biology and prognostication.

Insertion of a FLAG-tag sequence at the end of exon 9 of the TBX5 gene in three induced pluripotent stem cell lines (DHMi004-A-4, DHMi004-A-5, DHMi004-A-6) by CRISPR/Cas9 technology.

The identification of TBX5-related regulatory sequences in genes essential for heart development is hampered by the absence of antibodies which allow precipitation of TBX5:DNA complexes. Employing CRISPR/Cas9 technology, we have inserted a FLAG-tag sequence at the end of exon 9 of the TBX5 gene prior to the stop codon by homologous recombination. The translated TBX5-FLAG fusion protein of the three iPSC lines can effectively be precipitated by anti-FLAG antibodies and, thus, allow the detection of specific TBX5-binding sites and their associated genes.

Low anterior resection syndrome and its impact on quality of life of ovarian carcinoma patients: A prospective longitudinal study.

OBJECTIVES: Bowel dysfunction is frequently reported in patients with ovarian carcinoma (OC). Our aim was to evaluate the incidence of low anterior resection syndrome (LARS) like symptoms in patients with primary OC and its impact on quality of life (QoL). METHODS: A prospective longitudinal observational cohort study was performed, including patients with newly diagnosed OC treated by primary or interval surgery with residual tumor <1 cm, from 2018 until 2021. Patients with a stoma or recurrence of disease were excluded. Intestinal dysfunction was assessed using the validated LARS score questionnaire pre- and postoperatively. There are 3 subgroups based on the results: no, minor, or major LARS. The impact on QoL was evaluated by an additional question to demonstrate the severity of patient's life impairment. RESULTS: The questionnaire was answered by 78 patients pre- and post-operatively. LARS like symptoms were reported preoperatively in 34.6% (24.4% minor/10.2% major) and significantly increased postoperatively to 47.4% (28.2% minor/19.2% major; p = 0.011). Moderate to severe impairment of QoL correlated with LARS scores pre- (80%) and post-operatively (90%). Patients with two bowel anastomoses (mean score 18.6 pre- and 24.9 post-operatively, p = 0.041) showed a significant increase of the questionnaire score. CONCLUSIONS: Major LARS like symptoms appear in 10% of OC patients preoperatively and significantly increase to almost two-fold postoperatively. Multiple bowel anastomoses had a significant risk for higher postoperative LARS score. QoL impairment correlates linearly with LARS positive scoring, independent on the timing of the complaints.

Correction: Iodine emission from the reactive uptake of ozone to simulated seawater.

Correction for 'Iodine emission from the reactive uptake of ozone to simulated seawater' by Stephanie R. Schneider et al., Environ. Sci.: Processes Impacts, 2023, 25, 254-263, https://doi.org/10.1039/D2EM00111J.

Avoiding Regrettable Replacements: Can the Introduction of Novel Functional Groups Move PFAS from Recalcitrant to Reactive?

Per- and polyfluoroalkyl substances (PFASs) are present in a range of commercial and consumer products. These chemicals are often high-performance surfactants or nonstick/water-repellant coatings due to their chemical stability; however, this stability leads to select PFAS being environmentally persistent. To facilitate degradation, new fluorosurfactant building blocks (F7C3-O-CHF-CF2-S-CH2-CH2-OH (FESOH), F3C-O-CHF-CF2-S-CH2-CH2-OH (MeFESOH), F7C3-O-CHF-CF2-O-CH2-CH2-OH (ProFdiEOH), F7C3-O-CHF-CF2-CH2-OH (ProFEOH), and F3C-O-CHF-CF2-O-CH2-CH2-OH (MeFdiEOH)) have been systematically developed with heteroatom linkages such as ethers, thioethers, and polyfluorinated carbons. The room temperature, gas-phase OH oxidation rate constants, and products of these chemicals were monitored in an atmospheric chamber to investigate their fate in the atmosphere. Analysis was performed using online high-resolution chemical ionization mass spectrometry (CIMS) using the iodide reagent ion and via offline UPLC-MS/MS. FESOH and MeFESOH, the thioether congeners, were observed to have the largest rate constants of kFESOH = 2.82 (±0.33) and kMeFESOH = 2.17 (±0.17) (×10-12 cm3 molecules-1 s-1, respectively). First-, second-, and third-generation products of OH oxidation were observed as a function of time, while product quantification yielded ultrashort perfluoropropionic acid (PFPrA) and short polyfluoroether acid species as the terminal products for FESOH and ProFdiEOH. There was evidence for MeFESOH being fully mineralized, demonstrating the potential benign chemical architecture.

Cutaneous Adverse Events of Systemic Melanoma Treatments: A Retrospective Single-Center Analysis.

Recent progress in the treatment of advanced melanoma has led to the improved survival of affected patients. However, novel treatments also lead to considerable and distinct skin toxicity. To further characterize cutaneous adverse events (AE) of systemic treatments, we conducted a single-center retrospective study of biopsy-proven cutaneous adverse events of melanoma treatment over a period of 10 years at the University Hospital of Zurich, Switzerland. In 102 identified patients, 135 individual skin AEs developed. Immune checkpoint blockade (ICB) was causal for 81 skin AEs, and 54 were related to targeted therapies (TT). Recorded types of skin AEs included lichenoid, maculopapular, acneiform, urticarial, panniculitis, folliculitis, psoriasiform, granulomatous, eczematous, and others. The incidence of skin AEs was higher with TT (18.54%) than with ICB (9.64%, p = 0.0029). Most AEs were low-grade, although 19.21% of AEs were common terminology criteria for adverse events (CTCAE) Grades 3 or 4. A large spectrum of skin AEs was documented during treatment of advanced melanoma, and distinct phenotypes were observed, depending on treatment classes. AEs occurred earlier during treatment with TT than with ICB, and distinct types of skin AEs were associated with respective treatment classes. This study comprehensively describes skin AEs occurring during systemic treatment for melanoma at a single center.

Acute megakaryoblastic leukaemia shows high frequency of chromosome 1q aberrations and dismal outcome.

Acute megakaryoblastic leukaemia (AMKL) is associated with poor prognosis. Limited information is available on its cytogenetics, molecular genetics and clinical outcome. We performed genetic analyses, evaluated prognostic factors and the value of allogeneic haematopoietic stem cell transplantation (allo-HSCT) in a homogenous adult AMKL patient cohort. We retrospectively analysed 38 adult patients with AMKL (median age: 58 years, range: 21-80). Most received intensive treatment in AML Cooperative Group (AMLCG) trials between 2001 and 2016. Cytogenetic data showed an accumulation of adverse risk markers according to ELN 2017 and an unexpected high frequency of structural aberrations on chromosome arm 1q (33%). Most frequently, mutations occurred in TET2 (23%), TP53 (23%), JAK2 (19%), PTPN11 (19%) and RUNX1 (15%). Complete remission rate in 33 patients receiving intensive chemotherapy was 33% and median overall survival (OS) was 33 weeks (95% CI: 21-45). Patients undergoing allo-HSCT (n = 14) had a superior median OS (68 weeks; 95% CI: 11-126) and relapse-free survival (RFS) of 27 weeks (95% CI: 4-50), although cumulative incidence of relapse after allo-HSCT was high (62%). The prognosis of AMKL is determined by adverse genetic risk factors and therapy resistance. So far allo-HSCT is the only potentially curative treatment option in this dismal AML subgroup.

Resilience in patients with complex regional pain syndrome 1-a cross-sectional analysis of patients participating in a cross-sectional cohort study.

OBJECTIVE: To assess the degree of resilience in patients with complex regional pain syndrome (CRPS) 1, to explore the relationship between resilience and patient-related outcome measurements and to describe a pattern of clinical manifestations associated with low resilience. METHODS: This study presents a cross-sectional analysis of baseline information collected from patients enrolled in a single center study between February 2019 and June 2021. Participants were recruited from the outpatient clinic of the Department of Physical Medicine & Rheumatology of the Balgrist University Hospital, Zurich, Switzerland. We used linear regression analysis to explore association of resilience with patient reported outcomes at baseline. Furthermore, we explored the impact of significant variables on the low degree resilience using logistic regression analysis. RESULTS: Seventy-one patients (females 90.1%, mean age 51.2 ± 12.9 years) were enrolled. There was no association between CRPS severity and the level of resilience. Quality of Life was positively correlated with resilience, as was pain self-efficacy. Pain catastrophizing was inversely correlated with the level of resilience. We observed a significant inverse association between anxiety, depression and fatigue and the level of resilience. The proportion of patients with a low resilience increased with higher level of anxiety, depression and fatigue on the PROMIS-29, without reaching statistical significance. CONCLUSION: Resilience seems to be an independent factor in CRPS 1 and is associated with relevant parameters of the condition. Therefore, caretakers may screen the current resilience status of CRPS 1 patients to offer a supplementary treatment approach. Whether specific resilience training modifies CRPS 1 course, requires further investigations.

Incidence and Prognostic Impact of Deleterious Germline Mutations in Primary Advanced Ovarian Carcinoma Patients.

Data on deleterious variants in genes other than BRCA1/2 remain limited. A retrospective cohort study was performed, including primary OC cases with TruRisk® germline gene panel testing between 2011 and 2020. Patients with testing after relapse were excluded. The cohort was divided into three groups: (A) no mutations, (B) deleterious BRCA1/2 mutations, and (C) deleterious mutations in other genes. A total of 702 patients met the inclusion criteria. Of these 17.4% (n = 122) showed BRCA1/2 mutations and a further 6.0% (n = 42) in other genes. Three-year overall survival (OS) of the entire cohort was significantly longer in patients with germline mutations (85%/82.8% for cohort B/C vs. 70.2% for cohort A, p < 0.001) and 3-year progression-free survival (PFS) only for cohort B (58.1% vs. 36.9%/41.6% in cohort A/C, p = 0.002). In multivariate analysis for the subgroup of advanced-stages of high-grade serous OC, both cohorts B/C were found to be independent factors for significantly better outcome, cohort C for OS (HR 0.46; 95% CI 0.25-0.84), and cohort B for both OS and PFS (HR 0.40; 95% CI 0.27-0.61 and HR 0.49; 95% CI 0.37-0.66, respectively). Germline mutations were detected in a quarter of OC patients, and a quarter of those in genes other than BRCA1/2. Germline mutations demonstrate in our cohort a prognostic factor and predict better prognosis for OC patients.

Correction of a deleterious TBX5 mutation in an induced pluripotent stem cell line (DHMi004-A-1) using a completely plasmid-free CRISPR/Cas 9 approach.

TBX5 is a transcription factor which plays an essential role at different checkpoints during cardiac differentiation. However, regulatory pathways affected by TBX5 still remain ill-defined. We have applied the CRISPR/Cas9 technology using a completely plasmid-free approach to correct a heterozygous causative "loss-of function" TBX5 mutation in an iPSC line (DHMi004-A), that has been established from a patient suffering from Holt-Oram syndrome (HOS). This isogenic iPSC line, DHMi004-A-1, represents a powerful in vitro tool to dissect the regulatory pathways affected by TBX5 in HOS.

The KORE-INNOVATION trial, a prospective controlled multi-site clinical study to implement and assess the effects of an innovative peri-operative care pathway for patients with ovarian cancer: rationale, methods and trial design.

BACKGROUND: Advanced ovarian cancer is managed by extensive surgery, which could be associated with high morbidity. A personalized pre-habilitation strategy combined with an 'enhanced recovery after surgery' (ERAS) pathway may decrease post-operative morbidity. PRIMARY OBJECTIVE: To analyze the effects of a combined multi-modal pre-habilitation and ERAS strategy on severe post-operative morbidity for patients with ovarian cancer (primary diagnosis or first recurrence) undergoing cytoreductive surgery. STUDY HYPOTHESIS: A personalized multi-modal pre-habilitation algorithm entailing a physical fitness intervention, nutritional and psycho-oncological support, completed by an ERAS pathway, reduces post-operative morbidity. TRIAL DESIGN: This is a prospective, controlled, non-randomized, open, interventional two-center clinical study. Endpoints will be compared with a three-fold control: (a) historic control group (data from institutional ovarian cancer databases); (b) prospective control group (assessed before implementing the intervention); and (c) matched health insurance controls. INCLUSION CRITERIA: Patients with ovarian, fallopian, or primary peritoneal cancer undergoing primary surgical treatment (primary ovarian cancer or first recurrence) can be included. The intervention group receives an additional multi-level study treatment: (1) standardized frailty assessment followed by (2) a personalized tri-modal pre-habilitation program and (3) peri-operative care according to an ERAS pathway. EXCLUSION CRITERIA: Inoperable disease or neoadjuvant chemotherapy, simultaneous diagnosis of simultaneous primary tumors, in case of interference with the overall prognosis (except for breast cancer); dementia or other conditions that impair compliance or prognosis. PRIMARY ENDPOINT: Reduction of severe post-operative complications (according to Clavien- Dindo Classification (CDC) III-V) within 30 days after surgery. SAMPLE SIZE: Intervention group (n=414, of which approximately 20% insure with the participating health insurance); historic control group (n=198); prospective control group (n=50), health insurance controls (for those intervention patients who are members of the participating health insurance). ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: The intervention phase started in December 2021 and will continue until June 2023. As of March 2023, 280 patients have been enrolled in the intervention group. The expected completion of the entire study is September 2024. TRIAL REGISTRATION: NCT05256576.

Multi-frame biomechanical and relaxometry analysis during in vivo loading of the human knee by spiral dualMRI and compressed sensing.

PURPOSE: Knee cartilage experiences repetitive loading during physical activities, which is altered during the pathogenesis of diseases like osteoarthritis. Analyzing the biomechanics during motion provides a clear understanding of the dynamics of cartilage deformation and may establish essential imaging biomarkers of early-stage disease. However, in vivo biomechanical analysis of cartilage during rapid motion is not well established. METHODS: We used spiral displacement encoding with stimulated echoes (DENSE) MRI on in vivo human tibiofemoral cartilage during cyclic varus loading (0.5 Hz) and used compressed sensing on the k-space data. The applied compressive load was set for each participant at 0.5 times body weight on the medial condyle. Relaxometry methods were measured on the cartilage before (T1ρ , T2 ) and after (T1ρ ) varus load. RESULTS: Displacement and strain maps showed a gradual shift of displacement and strain in time. Compressive strain was observed in the medial condyle cartilage and shear strain was roughly half of the compressive strain. Male participants had more displacement in the loading direction compared to females, and T1ρ values did not change after cyclic varus load. Compressed sensing reduced the scanning time up to 25% to 40% when comparing the displacement maps and substantially lowered the noise levels. CONCLUSION: These results demonstrated the ease of which spiral DENSE MRI could be applied to clinical studies because of the shortened imaging time, while quantifying realistic cartilage deformations that occur through daily activities and that could serve as biomarkers of early osteoarthritis.

Validation and refinement of the 2022 European LeukemiaNet genetic risk stratification of acute myeloid leukemia.

The revised 2022 European LeukemiaNet (ELN) AML risk stratification system requires validation in large, homogeneously treated cohorts. We studied 1118 newly diagnosed AML patients (median age, 58 years; range, 18-86 years) who received cytarabine-based induction chemotherapy between 1999 and 2012 and compared ELN-2022 to the previous ELN-2017 risk classification. Key findings were validated in a cohort of 1160 mostly younger patients. ELN-2022 reclassified 15% of patients, 3% into more favorable, and 12% into more adverse risk groups. This was mainly driven by patients reclassified from intermediate- to adverse-risk based on additional myelodysplasia-related mutations being included as adverse-risk markers. These patients (n = 79) had significantly better outcomes than patients with other adverse-risk genotypes (5-year OS, 26% vs. 12%) and resembled the remaining intermediate-risk group. Overall, time-dependent ROC curves and Harrel's C-index controlling for age, sex, and AML type (de novo vs. sAML/tAML) show slightly worse prognostic discrimination of ELN-2022 compared to ELN-2017 for OS. Further refinement of ELN-2022 without including additional genetic markers is possible, in particular by recognizing TP53-mutated patients with complex karyotypes as "very adverse". In summary, the ELN-2022 risk classification identifies a larger group of adverse-risk patients at the cost of slightly reduced prognostic accuracy compared to ELN-2017.

Mechanical memory stored through epigenetic remodeling reduces cell therapeutic potential.

Understanding how cells remember previous mechanical environments to influence their fate, or mechanical memory, informs the design of biomaterials and therapies in medicine. Current regeneration therapies, such as cartilage regeneration procedures, require 2D cell expansion processes to achieve large cell populations critical for the repair of damaged tissues. However, the limit of mechanical priming for cartilage regeneration procedures before inducing long-term mechanical memory following expansion processes is unknown, and mechanisms defining how physical environments influence the therapeutic potential of cells remain poorly understood. Here, we identify a threshold to mechanical priming separating reversible and irreversible effects of mechanical memory. After 16 population doublings in 2D culture, expression levels of tissue-identifying genes in primary cartilage cells (chondrocytes) are not recovered when transferred to 3D hydrogels, while expression levels of these genes were recovered for cells only expanded for eight population doublings. Additionally, we show that the loss and recovery of the chondrocyte phenotype correlates with a change in chromatin architecture, as shown by structural remodeling of the trimethylation of H3K9. Efforts to disrupt the chromatin architecture by suppressing or increasing levels of H3K9me3 reveal that only with increased levels of H3K9me3 did the chromatin architecture of the native chondrocyte phenotype partially return, along with increased levels of chondrogenic gene expression. These results further support the connection between the chondrocyte phenotype and chromatin architecture, and also reveal the therapeutic potential of inhibitors of epigenetic modifiers as disruptors of mechanical memory when large numbers of phenotypically suitable cells are required for regeneration procedures.