Regulation with cell size ensures mitochondrial DNA homeostasis during cell growth.

To maintain stable DNA concentrations, proliferating cells need to coordinate DNA replication with cell growth. For nuclear DNA, eukaryotic cells achieve this by coupling DNA replication to cell-cycle progression, ensuring that DNA is doubled exactly once per cell cycle. By contrast, mitochondrial DNA replication is typically not strictly coupled to the cell cycle, leaving the open question of how cells maintain the correct amount of mitochondrial DNA during cell growth. Here, we show that in budding yeast, mitochondrial DNA copy number increases with cell volume, both in asynchronously cycling populations and during G1 arrest. Our findings suggest that cell-volume-dependent mitochondrial DNA maintenance is achieved through nuclear-encoded limiting factors, including the mitochondrial DNA polymerase Mip1 and the packaging factor Abf2, whose amount increases in proportion to cell volume. By directly linking mitochondrial DNA maintenance to nuclear protein synthesis and thus cell growth, constant mitochondrial DNA concentrations can be robustly maintained without a need for cell-cycle-dependent regulation.

Functional biomarkers derived from computed tomography and magnetic resonance imaging differentiate PDAC subgroups and reveal gemcitabine-induced hypo-vascularization.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is a molecularly heterogeneous tumor entity with no clinically established imaging biomarkers. We hypothesize that tumor morphology and physiology, including vascularity and perfusion, show variations that can be detected by differences in contrast agent (CA) accumulation measured non-invasively. This work seeks to establish imaging biomarkers for tumor stratification and therapy response monitoring in PDAC, based on this hypothesis. METHODS AND MATERIALS: Regional CA accumulation in PDAC was correlated with tumor vascularization, stroma content, and tumor cellularity in murine and human subjects. Changes in CA distribution in response to gemcitabine (GEM) were monitored longitudinally with computed tomography (CT) Hounsfield Units ratio (HUr) of tumor to the aorta or with magnetic resonance imaging (MRI) ΔR1 area under the curve at 60 s tumor-to-muscle ratio (AUC60r). Tissue analyses were performed on co-registered samples, including endothelial cell proliferation and cisplatin tissue deposition as a surrogate of chemotherapy delivery. RESULTS: Tumor cell poor, stroma-rich regions exhibited high CA accumulation both in human (meanHUr 0.64 vs. 0.34, p < 0.001) and mouse PDAC (meanAUC60r 2.0 vs. 1.1, p < 0.001). Compared to the baseline, in vivo CA accumulation decreased specifically in response to GEM treatment in a subset of human (HUr -18%) and mouse (AUC60r -36%) tumors. Ex vivo analyses of mPDAC showed reduced cisplatin delivery (GEM: 0.92 ± 0.5 mg/g, vs. vehicle: 3.1 ± 1.5 mg/g, p = 0.004) and diminished endothelial cell proliferation (GEM: 22.3% vs. vehicle: 30.9%, p = 0.002) upon GEM administration. CONCLUSION: In PDAC, CA accumulation, which is related to tumor vascularization and perfusion, inversely correlates with tumor cellularity. The standard of care GEM treatment results in decreased CA accumulation, which impedes drug delivery. Further investigation is warranted into potentially detrimental effects of GEM in combinatorial therapy regimens.

Increasing normality-persisting barriers: Current socio-demographic characteristics of 350 individuals diagnosed with gender dysphoria.

INTRODUCTION: The number of individuals requesting medical treatment for gender dysphoria has increased significantly within the past years. Our purpose was to examine current biographic and socio-demographic characteristics and aspects of legal gender reassignment. DESIGN: Medical files from n = 350 individuals of a German Endocrine outpatient clinic were collected from 2009 to 2017 and analysed retrospectively. RESULTS: Ratio of transwomen to transmen equates to 1:1.89 with a remarkable increase of transmen by the year 2013, showing a reversal of gender distribution compared with previous studies for the first time. Use of illegal substances or self-initiated hormone therapy was rare (4.6 and 2.1%). Satisfaction with gender-affirming hormone therapy was significantly higher in transmen than in transwomen (100% vs 96.2%, P = .005). Use of antidepressants declined significantly after onset of hormone treatment in transmen (13% vs 7%; P = .007). The number of individuals with a graduation diploma was only about half as high as in the general population (14.3% vs 27.3%), whereas unemployment rate was more than twice as high (14% vs 6.9%). Median latency between application for legal gender reassignment and definitive court decision was 9 months. CONCLUSIONS: Our data provide possible indications for a decline of psychosocial burden in individuals diagnosed with gender dysphoria over the last years. However, affected individuals are still limited in their occupational and financial opportunities as well as by a complex and expensive procedure of legal gender reassignment in Germany.

Safety and rapid efficacy of guideline-based gender-affirming hormone therapy: an analysis of 388 individuals diagnosed with gender dysphoria.

OBJECTIVE: Hormone treatment is an important part of gender reassignment therapy in gender dysphoria. Previous data about efficacy and safety are commonly based on small cohorts or they comprise former cohorts under meanwhile obsolete therapy regimes. Our objective was to investigate these topics in a large cohort of individuals under guideline-based treatment. DESIGN/METHODS: Cohort study of medical files of n = 155 male-to-female (transwomen) and n = 233 female-to-male transgender persons (transmen) of an Endocrine outpatient clinic between 2009 and 2017. RESULTS: Median time to reach amenorrhoea in transmen under testosterone monotherapy was 3 months, regardless of whether testosterone undecanoat or gel was used. Transmen with higher levels of hemoglobin 3-4 months after onset of GAHT had a greater chance to reach amenorrhea early, whereas testosterone levels showed no significant correlation (hemoglobin: HR: 1.639; 95% CI: 1.036-2.591, P = 0.035; testosterone: HR: 0.999; 95% CI: 0.998-1.001, P = 0.490). Estradiol levels (ρ -0.117; P = 0.316) had no significant influence on breast development in transwomen. Testosterone levels (ρ -0.398; P < 0.001) and FAI (ρ 0.346; P = 0.004) were significantly negatively correlated with reached Tanner stage. Liver values and blood lipids showed an alignment to reference range of the required sex in both groups. Relevant elevations of liver values were rare (2.44% in transmen, 4.23% in transwomen) and transient in most cases. Most relevant side effects were acne (44.8%), respectively erythrocytosis (up to 5.6%) in transmen and venous thrombembolism (1.9%) in transwomen. CONCLUSIONS: Gender-affirming hormone therapy in accordance with current clinical practice guidelines is efficient and safe.