Loss of epigenetic information as a cause of mammalian aging.

All living things experience an increase in entropy, manifested as a loss of genetic and epigenetic information. In yeast, epigenetic information is lost over time due to the relocalization of chromatin-modifying proteins to DNA breaks, causing cells to lose their identity, a hallmark of yeast aging. Using a system called "ICE" (inducible changes to the epigenome), we find that the act of faithful DNA repair advances aging at physiological, cognitive, and molecular levels, including erosion of the epigenetic landscape, cellular exdifferentiation, senescence, and advancement of the DNA methylation clock, which can be reversed by OSK-mediated rejuvenation. These data are consistent with the information theory of aging, which states that a loss of epigenetic information is a reversible cause of aging.

Non-invasive tests for clinically significant portal hypertension after HCV cure.

BACKGROUND & AIMS: Non-invasive tests (NITs) for clinically significant portal hypertension (CSPH; hepatic venous pressure gradient [HVPG] ≥10 mmHg) have predominantly been studied in patients with active HCV infection. Investigations after HCV cure are limited and have yielded conflicting results. We conducted a pooled analysis to determine the diagnostic/prognostic utility of liver stiffness measurement (LSM)/platelet count (PLT) in this setting. METHODS: A total of 418 patients with pre-treatment HVPG ≥6 mmHg who achieved sustained virological response (SVR) and underwent post-treatment HVPG measurement were assessed, of whom 324 (HVPG/NIT-cohort) also had paired data on pre-/post-treatment LSM/PLT. The derived LSM/PLT criteria were then validated against the direct endpoint decompensation in 755 patients with compensated advanced chronic liver disease (cACLD) with SVR (cACLD-validation-cohort). RESULTS: HVPG/NIT-cohort: Among patients with cACLD, the pre-/post-treatment prevalence of CSPH was 80%/54%. The correlation between LSM/HVPG increased from pre- to post-treatment (r = 0.45 vs. 0.60), while that of PLT/HVPG remained unchanged. For given LSM/PLT values, HVPG tended to be lower post- vs. pre-treatment, indicating the need for dedicated algorithms. Combining post-treatment LSM/PLT yielded a high diagnostic accuracy for post-treatment CSPH in cACLD (AUC 0.884; 95% CI 0.843-0.926). Post-treatment LSM <12 kPa & PLT >150 G/L excluded CSPH (sensitivity: 99.2%), while LSM ≥25 kPa was highly specific for CSPH (93.6%). cACLD-validation-cohort: the 3-year decompensation risk was 0% in the 42.5% of patients who met the LSM <12 kPa & PLT >150 G/L criteria. In patients with post-treatment LSM ≥25 kPa (prevalence: 16.8%), the 3-year decompensation risk was 9.6%, while it was 1.3% in those meeting none of the above criteria (prevalence: 40.7%). CONCLUSIONS: NITs can estimate the probability of CSPH after HCV cure and predict clinical outcomes. Patients with cACLD but LSM <12 kPa & PLT>150 G/L may be discharged from portal hypertension surveillance if no co-factors are present, while patients with LSM ≥25 kPa require surveillance/treatment. LAY SUMMARY: Measurement of liver stiffness by a specific ultrasound device and platelet count (a simple blood test) are broadly used for the non-invasive diagnosis of increased blood pressure in the veins leading to the liver, which drives the development of complications in patients with advanced liver disease. The results of our pooled analysis refute previous concerns that these tests are less accurate after the cure of hepatitis C virus (HCV) infection. We have developed diagnostic criteria that facilitate personalized management after HCV cure and allow for a de-escalation of care in a high proportion of patients, thereby decreasing disease burden.

Age and sex influence the response in lipid metabolism of dehydrated Wistar rats.

Aging is associated a decrease in thirst sensation, which makes old people more susceptible to dehydration. Dehydration produces energy metabolism alterations. Our objective was to determinate the effect of water deprivation (WD) in the lipid metabolism of old male and female rats. Here we show that in the state of WD, aging and sex alters retroperitoneal white adipose tissue (R-WAT) weight of rats, WD old female rats had more lipolysis products than old male rats, a sexual dimorphism in the hormonal response related with metabolism of the adipose tissue of old rats during WD, the expression of P-para mRNA in R-WAT did not present any alteration in animals submitted to WD, the expression of Aqp7 mRNA in R-WAT is altered by WD, age, and sex. Also, WD stimulated an increase in the plasma concentration of oxytocin and the expression of mRNA of the oxytocin receptors in R-WAT.

Cystoid Macular Edema 18 Years after Anterior Chamber Phakic Intraocular Lens Implantation.

We report a case of a 54-year-old female patient who underwent PAC-IOL implantation 18 years prior to presentation. The patient had a best corrected visual acuity (BCVA) 20/20 in the right eye (OD) postoperatively with normal eye exam on routine follow-up since then. The patient presented for acute onset decreased visual acuity in the right eye. BCVA was 20/60, and exam showed blunted macular reflex with no evidence of inflammation. Optical coherence tomography (OCT) showed CME. She was started on topical treatment (ketorolac 0.5%) OD four times daily. Three weeks later, the patient had a BCVA of 20/20 OD with a normal macular reflex and an OCT showing the resolution of the CME. To our knowledge, this is the first reported case of a CME 18 years post PAC-IOL implantation. The possible cause of this incidence could be related to subclinical intraocular inflammation. Ophthalmologists should be aware of the possibility of such a latent CME post-PAC-IOL implantation.

Hydrophilic Lens Opacification after Intravitreal Anti-VEGF Injections: A Case Series.

Our objective in this retrospective case series was to report 4 cases of hydrophilic intraocular lens (IOL) opacifications after repeated intravitreal bevacizumab injections. This is a retrospective analysis of all the cases of IOL opacifications presenting to a tertiary referral ophthalmic center in Beirut between January 2013 and January 2019. Four cases were included in the study, of which one was treated for vitreal hemorrhage, the other for macular edema secondary to wet age-related macular edema, and the rest for macular edema secondary to diabetic retinopathy. The mean age of the patients was 71 years with a male predominance and a mean of 5 injections. The IOL opacifications appeared approximately 24 months after first bevacizumab injection. The opacification could be explained by multiple theories such as a possible anterior or posterior segment subclinical inflammation secondary to intraocular interventions, interaction between the hydrophilic properties of the IOLs and anti-vascular endothelial growth factor injection's content, impurities transmission during injection, or faulty IOL manufacturing.

AMPA and angiotensin type 1 receptors are necessary for hemorrhage-induced vasopressin secretion.

Hypovolemia induced by hemorrhage is a common clinical complication, which stimulates vasopressin (AVP) secretion by the neurohypophysis in order to retain body water and maintain blood pressure. To evaluate the role of brain L-glutamate and angiotensin II on AVP secretion induced by hypovolemia we induced hemorrhage (∼25% of blood volume) after intracerebroventricular (icv) administration of AP5, NBQX, or losartan, which are NMDA, AMPA, and AT1 receptor antagonists, respectively. Hemorrhage significantly increased plasma AVP levels in all groups. The icv injection of AP5 did not change AVP secretion in response to hemorrhage. Conversely, icv administration of both NBQX and losartan significantly decreased plasma AVP levels after hemorrhage. Therefore, the blockade of AMPA and AT1 receptors impaired AVP secretion in response to hemorrhage, suggesting that L-glutamate and angiotensin II acted in these receptors to increase AVP secretion in response to hemorrhage-induced hypovolemia.

An analysis of contact tracing protocol in an over-dispersed SEIQR Covid-like disease.

The aim of this work is to study an over-dispersed SEIQR infectious disease and obtain optimal methods of contact tracing. A prototypical example of such a disease is that of the current SARS-CoV-2 pandemic. In consequence, this study is immediately applicable to the current health crisis. In this paper, we introduce both a discrete and continuous model for various modes of contact tracing. From the continuous model, we derive a basic reproductive number and study the stability of the equilibrium points. We also implement the continuous and discrete models numerically and further analyze the effectiveness of different types of contact tracing and their cost on society. Additionally, through these simulations, we also study the effect that various parameters of the disease have on its evolution.

A novel electrosurgical divider: performance in a self-controlled tonsillectomy study.

PURPOSE: Tonsillectomies are among the most common surgeries in otorhinolaryngology. A novel electrosurgical temperature-controlled instrument (device) promises rapid tonsillectomies and might reduce postoperative pain, but comparative studies to assess performance are warranted. METHODS: This randomized self-controlled clinical trial was conducted from October 2019 to October 2020 at the Department of Otorhinolaryngology, Head and Neck Surgery of the Medical University of Vienna. Forty-eight patients underwent a tonsillectomy with the device on one side and using cold-steel with localized bipolar cauterization on the other side (control). Main outcomes were the time for tonsil removal (per side) and the time to stop bleeding (per side). Secondary measurements were postoperative pain, assessed once on day 0 and five times on days 1, 3, 5, 7, and 10. Postoperative bleeding episodes and consequences were recorded. RESULTS: Device tonsillectomies were performed significantly faster than controls; the mean surgical time difference was 209 s (p < 0.001, 95% CI 129; 288). Intraoperative blood loss was significantly lower on the device side (all p < 0.05). Postoperative measurements of pain and bleeding were similar for both sides. Two return-to-theatre secondary bleeding events were recorded for the control side. CONCLUSION: The novel electrosurgical temperature-controlled divider reduced the tonsillectomy surgical time and intraoperative blood loss, with no apparent negative effects on postoperative pain or bleeding, compared to a cold-steel tonsillectomy with localized bipolar cauterization. In time-restricted settings, the device could be beneficial, particularly after familiarization with device handling. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03793816.

Corneal Haze Secondary to Corneal Collagen Cross-linking in Keratoconus Patients: Treatment and Outcomes.

PURPOSE: The purpose of this study was to evaluate the outcome of patients presenting with mild-to-moderate corneal haze after undergoing corneal collagen cross-linking (CXL) for keratoconus (KCN) and their response to a proposed standardized topical steroid-based treatment. METHODS: This study included 19 eyes of 14 patients presenting with corneal haze after undergoing CXL for KCN. Corrected distance visual acuity, corneal thickness and Kmax values by Pentacam® Scheimpflug tomography, as well as subjective corneal haze changes were evaluated before and after a topical steroid- and cyclosporine-based treatment. RESULTS: Visual acuity improved after the completion of the treatment by 0.043 logMAR (P = 0.017) and Kmax values decreased by 1.17D (P = 0.0024), while the corneal thinnest pachymetry remained stable. Data collected from the examiner's slit-lamp examination description revealed that seven eyes had a decrease in haze compared to 12 eyes with stable or no changes in the haze. CONCLUSION: Our findings suggest an improvement in visual acuity and possible corneal flattening with decreasing Kmax after the completion of topical steroids with taper course treatment in patients suffering from corneal haze post-CXL. This paper also highlights the importance of postcross-linking anti-inflammatory treatment and close follow-up.

AMPA and angiotensin type 1 receptors are necessary for hemorrhage-induced vasopressin secretion

Hypovolemia induced by hemorrhage is a common clinical complication, which stimulates vasopressin (AVP) secretion by the neurohypophysis in order to retain body water and maintain blood pressure. To evaluate the role of brain L-glutamate and angiotensin II on AVP secretion induced by hypovolemia we induced hemorrhage (∼25% of blood volume) after intracerebroventricular (icv) administration of AP5, NBQX, or losartan, which are NMDA, AMPA, and AT1 receptor antagonists, respectively. Hemorrhage significantly increased plasma AVP levels in all groups. The icv injection of AP5 did not change AVP secretion in response to hemorrhage. Conversely, icv administration of both NBQX and losartan significantly decreased plasma AVP levels after hemorrhage. Therefore, the blockade of AMPA and AT1 receptors impaired AVP secretion in response to hemorrhage, suggesting that L-glutamate and angiotensin II acted in these receptors to increase AVP secretion in response to hemorrhage-induced hypovolemia.

Why Does Rubin's Vase Differ Radically From Optical Illusions? Framing Effects Contra Cognitive Illusions.

Many researchers use the term "context" loosely to denote diverse kinds of reference points. The issue is not about terminology but rather about the common conflation of one kind of reference points, such as rules of perception, which is responsible for optical illusions, with another kind, known as "context" or "frame," as exemplified in Rubin's vase. Many researchers regard Rubin's vase as a special kind of optical illusions. This paper rather argues that the two phenomena are radically different. Optical illusions are occasional mistakes that people quickly recognize and eagerly correct, while the different figures of Rubin's vase are not mistakes but, rather, the outcomes of different perspectives that do not need correction. The competing figures in Rubin's vase can, at best, in light of more information, be more warranted or unwarranted. This paper discusses at length one ramification of the proposed distinction. The framing effects, such as loss/gain frame, are the products of contexts and, hence, resemble greatly the figures in Rubin's vase. In contrast, cognitive illusions generated occasionally by the rules of thumb (heuristics) are mistakes and, hence, resemble optical illusions. The proposed distinction carries other ramifications regarding, e.g., happiness studies, moral judgments, and the new philosophy of science.

Combined effects of PNPLA3, TM6SF2 and HSD17B13 variants on severity of biopsy-proven non-alcoholic fatty liver disease.

OBJECTIVE: Several single-nucleotide polymorphisms have been identified to be disadvantageous or protective in regard to disease severity in patients with non-alcoholic fatty liver disease (NAFLD). However, it is unclear, whether including genetic risk factor(s) either alone or combined into risk stratification algorithms for NAFLD actually provides incremental benefit over clinical risk factors. DESIGN: Patients with biopsy-proven NAFLD were genotyped for the PNPLA3-rs738409(minor allele:G), TM6SF2-rs58542926(minor allele:T) and HSD17B13- rs72613567 (minor allele:TA) variants. The NAFLD activity score (NAS) and fibrosis stage (F0-F4) were used to grade and stage all liver biopsy samples. Patients from seven centers throughout Central Europe were considered for the study. RESULTS: 703 patients were included: NAS ≥ 5:173(24.6%); Fibrosis: F3-4:81(11.5%). PNPLA3 G/G genotype was associated with a NAS ≥ 5(aOR 2.23, p = 0.007) and advanced fibrosis (aOR-3.48, p < 0.001).TM6SF2 T/- was associated with advanced fibrosis (aOR 1.99, p = 0.023). HSD17B13 TA/- was associated with a lower probability of NAS ≥ 5(TA/T: aOR 0.65, p = 0.041, TA/TA: aOR 0.40, p = 0.033). Regarding the predictive capability for NAS ≥ 5, well-known risk factors (age, sex, BMI, diabetes, and ALT; baseline model) had an AUC of 0.758, Addition of PNPLA3(AUC 0.766), HSB17B13(AUC 0.766), and their combination(AUC 0.775), but not of TM6SF2(AUC 0.762), resulted in a higher diagnostic accuracy of the model. Addition of genetic markers for the prediction of advanced fibrosis (baseline model: age, sex, BMI, diabetes: AUC 0.777) resulted in a higher AUC if PNPLA3(AUC 0.789), and TM6SF2(AUC 0.786) but not if HSD17B13(0.777) were added. CONCLUSION: In biopsy-proven NAFLD, PNPLA3 G/-, TM6SF2 T/- and HSD17B13 TA/- carriage are associated with severity of NAFLD. Incorporating these genetic risk factors into risk stratification models might improve their predictive accuracy for severity of NAFLD and/or advanced fibrosis on liver biopsy.

Is "willpower" a scientific concept? Suppressing temptation contra resolution in the face of adversity.

The distinction that Ainslie draws among the triple-phenomena "suppression," "resolve," and "habit" is a great advance in decision making theory. But the conceptual machinery "willpower," and its underpinning distinction between small/soon (SS) rewards as opposed to large/later (LL) rewards, provides a faulty framework to understand the triple-phenomena.

POSTOPERATIVE MOVEMENT OF THE FOVEA AFTER SUCCESSFUL SURGERY IN PATIENTS WITH IDIOPATHIC EPIRETINAL MEMBRANES.

PURPOSE: To evaluate the change in the fovea's postoperative location after successful pars plana vitrectomy with combined epiretinal and internal limiting membrane peeling in patients with idiopathic epiretinal membranes (iERMs). METHODS: In this prospective study 32 eyes of 32 patients with iERMs were followed from baseline before until 3 months after surgery. Study measures included 4-m Early Treatment Diabetic Retinopathy Study best-corrected visual acuity, enhanced-depth imaging-optical coherence tomography, and intraoperative fundus photographs. Foveal movement was assessed by measuring the change in the papillofoveal distance (∆PFD). RESULTS: Mean ∆PFD in the study eye was -124 µm (±138) and -272 µm (±213) one day and 3 months after surgery, respectively. Mean ∆PFD after 3 months was greater in the study than in the fellow eye (P < 0.001). ∆PFD at Month 3 did not correlate with the internal limiting membrane area peeled (P = 0.78). CONCLUSION: Foveal movement starts immediately after surgery and causes a statistically significant reduction in PFD after uneventful macular pucker surgery. ∆PFD correlates statistically significantly with baseline best-corrected visual acuity and baseline central retinal thickness. The internal limiting membrane peeling size had no significant effect on the amount of postoperative foveal dislocation.

Genotype imputation and variability in polygenic risk score estimation.

BACKGROUND: Polygenic risk scores (PRSs) are a summarization of an individual's genetic risk for a disease or trait. These scores are being generated in research and commercial settings to study how they may be used to guide healthcare decisions. PRSs should be updated as genetic knowledgebases improve; however, no guidelines exist for their generation or updating. METHODS: Here, we characterize the variability introduced in PRS calculation by a common computational process used in their generation-genotype imputation. We evaluated PRS variability when performing genotype imputation using 3 different pre-phasing tools (Beagle, Eagle, SHAPEIT) and 2 different imputation tools (Beagle, Minimac4), relative to a WGS-based gold standard. Fourteen different PRSs spanning different disease architectures and PRS generation approaches were evaluated. RESULTS: We find that genotype imputation can introduce variability in calculated PRSs at the individual level without any change to the underlying genetic model. The degree of variability introduced by genotype imputation differs across algorithms, where pre-phasing algorithms with stochastic elements introduce the greatest degree of score variability. In most cases, PRS variability due to imputation is minor (< 5 percentile rank change) and does not influence the interpretation of the score. PRS percentile fluctuations are also reduced in the more informative tails of the PRS distribution. However, in rare instances, PRS instability at the individual level can result in singular PRS calculations that differ substantially from a whole genome sequence-based gold standard score. CONCLUSIONS: Our study highlights some challenges in applying population genetics tools to individual-level genetic analysis including return of results. Rare individual-level variability events are masked by a high degree of overall score reproducibility at the population level. In order to avoid PRS result fluctuations during updates, we suggest that deterministic imputation processes or the average of multiple iterations of stochastic imputation processes be used to generate and deliver PRS results.

Impact of Timely Public Health Measures on Kidney Transplantation in Austria during the SARS-CoV-2 Outbreak-A Nationwide Analysis.

SARS-CoV-2 led to considerable morbidity/mortality worldwide and tremendously impacted on daily life. Strict lockdown measures were implemented early to contain the viral outbreak in Austria. Massive changes in organizational structures of healthcare facilities followed with unclear implications on the care of non-COVID-19-affected patients. We studied the nationwide impact of COVID-19 on kidney transplantation in Austria during the first six months of 2020. Concurrent with general lockdown measures, all kidney transplant activity was suspended from 13 March to 9 April. Nevertheless, between January and June, total transplant (p = 0.48) and procured donor organ numbers (p = 0.6) did not differ significantly from earlier years. Ten (0.18%) of 5512 prevalent Austrian kidney transplant recipients were diagnosed with SARS-CoV-2. The case fatality rate (one death; 10%) in renal transplant patients was less than in other countries but higher than in Austria's general population (2.4%). We conclude that early and strict general lockdown measures imposed by the government allowed an early, however cautious, re-opening of Austrian transplant programs and played a crucial role for the favorable outcomes of SARS-CoV-2 in Austrian kidney transplant patients. Even though it may be uncertain whether similar results may be obtainable in other countries, the findings may support early intervention strategies during similar episodes in the future.

Effects of Hyperosmolality on Hypothalamic Astrocytic Area, mRNA Expression and Glutamate Balance In Vitro.

During prolonged dehydration, body fluid homeostasis is challenged by extracellular fluid (ECF) hyperosmolality, which induce important functional changes in the hypothalamus, in parallel with other effector responses, such as the activation of the local renin-angiotensin system (RAS). Therefore, in the present study we investigated the role of sodium-driven ECF hyperosmolality on glial fibrillary acid protein (GFAP) immunoreactivity and protein expression, membrane capacitance, mRNA expression of RAS components and glutamate balance in cultured hypothalamic astrocytes. Our data show that hypothalamic astrocytes respond to increased hyperosmolality with a similar decrease in GFAP expression and membrane capacitance, indicative of reduced cellular area. Hyperosmolality also downregulates the transcript levels of angiotensinogen and both angiotensin-converting enzymes, whereas upregulates type 1a angiotensin II receptor mRNA. Incubation with hypertonic solution also decreases the immunoreactivity to the membrane glutamate/aspartate transporter (GLAST) as well as tritiated-aspartate uptake by astrocytes. This latter effect is completely restored to basal levels when astrocytes previously exposed to hypertonicity are incubated under isotonic conditions. Together with a direct effect on two important local signaling systems (glutamate and RAS), these synaptic rearrangements driven by astrocytes may accomplish for a coordinated increase in the excitatory drive onto the hypothalamic neurosecretory system, ultimately culminating with increased AVP release in response to hyperosmolality.

Aging and low-intensity exercise change oxidative biomarkers in brain regions and radiographic measures of femur of Wistar rats.

We investigated changes in oxidative biomarkers in brain regions such as brainstem, cerebellum, and cerebral cortex of 3-, 6-, 18-, 24-, and 30-month-old rats. We also assessed the effects of low-intensity exercise on these biomarkers in these regions of 6-, 18-, and 24-month-old rats that started exercise on a treadmill at 3, 15, and 21 months of age, respectively. Radiographic images of the femur were taken for all rats. A total of 25 rats (age: twelve 6-, ten 18-, ten 24-, and three 30-month-old rats) were used. Lipid hydroperoxide levels increased in cerebellum at 18 months. Total antioxidant activity exhibited lowest values in brainstem at 3 months. Superoxide dismutase activity did not exhibit significant changes during aging. Total thiol content exhibited lowest values in brain regions of 24- and 30-month-old rats. Exercise reduced total thiol content in brainstem at 6 months, but no change occurred in other regions and other ages. Femur increased its length and width and cortical thickness with advancing age. No change occurred in medullary width. Radiolucency increased and sclerosis was found in cortical and medullary bone with advancing age. Exercise reduced radiolucency and medullary sclerosis. Therefore, aging differentially changed oxidative biomarkers in different brain regions and radiographic measures of the femur. Low-intensity exercise only ameliorated some radiographic measurements of femur. Since the present study possessed limitations (small number of rats per group), a beneficial effect of regular low-intensity exercise on oxidative markers in brain cannot be ruled out.

Brain osmo-sodium sensitive channels and the onset of sodium appetite.

The aim of the present study was to determine whether the TRPV1 channel is involved in the onset of sodium appetite. For this purpose, we used TRPV1-knockout mice to investigate sodium depletion-induced drinking at different times (2/24 h) after furosemide administration combined with a low sodium diet (FURO-LSD). In sodium depleted wild type and TRPV1 KO (SD-WT/SD-TPRV1-KO) mice, we also evaluated the participation of other sodium sensors, such as TPRV4, NaX and angiotensin AT1-receptors (by RT-PCR), as well as investigating the pattern of neural activation shown by Fos immunoreactivity, in different nuclei involved in hydromineral regulation. TPRV1 SD-KO mice revealed an increased sodium preference, ingesting a higher hypertonic cocktail in comparison with SD-WT mice. Our results also showed in SD-WT animals that SFO-Trpv4 expression increased 2 h after FURO-LSD, compared to other groups, thus supporting a role of SFO-Trpv4 channels during the hyponatremic state. However, the SD-TPRV1-KO animals did not show this early increase, and maybe as a consequence drank more hypertonic cocktail. Regarding the SFO-NaX channel expression, in both genotypes our findings revealed a reduction 24 h after FURO-LSD. In addition, there was an increase in the OVLT-NaX expression of SD-WT 24 h after FURO-LSD, suggesting the participation of OVLT-NaX channels in the appearance of sodium appetite, possibly as an anticipatory response in order to limit sodium intake and to induce thirst. Our work demonstrates changes in the expression of different osmo­sodium-sensitive channels at specific nuclei, related to the body sodium status in order to stimulate an adequate drinking.