Cardiomyocyte-fibroblast interaction regulates ferroptosis and fibrosis after myocardial injury.

Neonatal mouse hearts have transient renewal capacity, which is lost in juvenile and adult stages. In neonatal mouse hearts, myocardial infarction (MI) causes an initial loss of cardiomyocytes. However, it is unclear which type of regulated cell death (RCD) occurs in stressed cardiomyocytes. In the current studies, we induced MI in neonatal and juvenile mouse hearts and showed that ischemic cardiomyocytes primarily undergo ferroptosis, a non-apoptotic and iron-dependent form of RCD. We demonstrated that cardiac fibroblasts (CFs) protect cardiomyocytes from ferroptosis through paracrine effects and direct cell-cell interaction. CFs show strong resistance to ferroptosis due to high ferritin expression. The fibrogenic activity of CFs, typically considered detrimental to heart function, is negatively regulated by paired-like homeodomain 2 (Pitx2) signaling from cardiomyocytes. In addition, Pitx2 prevents ferroptosis in cardiomyocytes by regulating ferroptotic genes. Understanding the regulatory mechanisms of cardiomyocyte survival and death can identify potentially translatable therapeutic strategies for MI.

Cardiomyocyte-fibroblast interaction regulates ferroptosis and fibrosis after myocardial injury.

Neonatal mouse hearts have transient renewal capacity which is lost in juvenile and adult hearts. After myocardial infarction (MI) in neonatal hearts, an initial loss of cardiomyocytes occurs but it is unclear through which type of regulated cell death (RCD). In the current studies, we induced MI in neonatal and juvenile mouse hearts, and show that ischemic cardiomyocytes primarily undergo ferroptosis, a non-apoptotic and iron-dependent form of RCD. We demonstrate that cardiac fibroblasts (CFs) protect cardiomyocytes from ferroptosis through paracrine factors and direct cell-cell interaction. CFs show strong resistance to ferroptosis due to high ferritin expression. Meanwhile, the fibrogenic role of CFs, typically considered detrimental to heart function, is negatively regulated by paired-like homeodomain 2 (Pitx2) signaling from cardiomyocytes. In addition, Pitx2 prevents ferroptosis in cardiomyocytes by regulating ferroptotic genes. Understanding the regulatory mechanisms of cardiomyocyte survival and death can identify potentially translatable therapeutic strategies for MI.

Glaucoma Drugs in the Pipeline.

Glaucoma is a chronic disease that can be challenging to treat for both patients and physicians. Most patients will require more than 1 medication over time to maintain their intraocular pressure (IOP) at a physiologically benign level. Patients may become refractory to existing compounds and many struggle with adherence to multiple topical drop regimens. The field of glaucoma therapeutics has been advancing rapidly with an emphasis on compounds comprising multiple molecules/mechanisms of action that offer additivity and are complementary to current therapeutics. Several new topical drop compounds directly targeting the trabecular meshwork (TM)/Schlemm canal/conventional outflow pathway to reduce outflow resistance have obtained US Food and Drug Administration approval in the past year. These include rho kinase inhibitors and nitric oxide donating compounds. Alternative therapies that offer long-term IOP lowering while removing the patient from the drug delivery system are moving forward in development. These include gene therapy and stem cell strategies, which could ease or eliminate the burden of topical drop self-administration for several years. Additionally, a variety of novel formulations and devices are in development that aim for controlled, steady state delivery of therapeutics over periods of months. The future of glaucoma therapy is focusing on an increase in specificity for the individual patient: their type of glaucoma; underlying mechanisms; genetic make-up; comorbid conditions; and rate of progression. Maintaining functional vision and improving patient outcomes remains the goal in glaucoma therapeutics. The current collection of novel therapeutics offers an expanded set of tools to achieve that goal.

Clinical associations with immature breathing in preterm infants: part 2-periodic breathing.

BACKGROUND: Periodic breathing (PB) is a normal immature breathing pattern in neonates that, if extreme, may be associated with pathologic conditions. METHODS: We used our automated PB detection system to analyze all bedside monitor chest impedance data on all infants <35 wk' gestation in the University of Virginia Neonatal Intensive Care Unit from 2009-2014 (n = 1,211). Percent time spent in PB was calculated hourly (>50 infant-years' data). Extreme PB was identified as a 12-h period with PB >6 SDs above the mean for gestational age (GA) and postmenstrual age and >10% time in PB. RESULTS: PB increased with GA, with the highest amount in infants 30-33 wk' GA at about 2 wk' chronologic age. Extreme PB was identified in 76 infants and in 45% was temporally associated with clinical events including infection or necrotizing enterocolitis (NEC), immunizations, or caffeine discontinuation. In 8 out of 28 cases of septicemia and 10 out of 21 cases of NEC, there was a >2-fold increase in %PB over baseline on the day prior to diagnosis. CONCLUSION: Infants <35 wk GA spend, on average, <6% of the time in PB. An acute increase in PB may reflect illness or physiological stressors or may occur without any apparent clinical event.

Clinical associations of immature breathing in preterm infants: part 1-central apnea.

BACKGROUND: Apnea of prematurity (AOP) is nearly universal among very preterm infants, but neither the apnea burden nor its clinical associations have been systematically studied in a large consecutive cohort. METHODS: We analyzed continuous bedside monitor chest impedance and electrocardiographic waveforms and oxygen saturation data collected on all neonatal intensive care unit (NICU) patients <35 wk gestation from 2009 to 2014 (n = 1,211; >50 infant-years of data). Apneas, with bradycardia and desaturation (ABDs), defined as central apnea ≥10 s associated with both bradycardia <100 bpm and oxygen desaturation <80%, were identified using a validated automated algorithm. RESULTS: Number and duration of apnea events decreased with increasing gestational age (GA) and postmenstrual age (PMA). ABDs were more frequent in infants <31 wk GA at birth but were not more frequent in those with severe retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), or severe intraventricular hemorrhage (IVH) after accounting for GA. In the day before diagnosis of late-onset septicemia and necrotizing enterocolitis, ABD events were increased in some infants. Many infants continued to experience short ABD events in the week prior to discharge home. CONCLUSION: Frequency of apnea events is a function of GA and PMA in infants born preterm, and increased apnea is associated with acute but not with chronic pathologic conditions.

Quantification of periodic breathing in premature infants.

Periodic breathing (PB), regular cycles of short apneic pauses and breaths, is common in newborn infants. To characterize normal and potentially pathologic PB, we used our automated apnea detection system and developed a novel method for quantifying PB. We identified a preterm infant who died of sudden infant death syndrome (SIDS) and who, on review of her breathing pattern while in the neonatal intensive care unit (NICU), had exaggerated PB.We analyzed the chest impedance signal for short apneic pauses and developed a wavelet transform method to identify repetitive 10-40 second cycles of apnea/breathing. Clinical validation was performed to distinguish PB from apnea clusters and determine the wavelet coefficient cutoff having optimum diagnostic utility. We applied this method to analyze the chest impedance signals throughout the entire NICU stays of all 70 infants born at 32 weeks' gestation admitted over a two-and-a-half year period. This group includes an infant who died of SIDS and her twin.For infants of 32 weeks' gestation, the fraction of time spent in PB peaks 7-14 d after birth at 6.5%. During that time the infant that died of SIDS spent 40% of each day in PB and her twin spent 15% of each day in PB.This wavelet transform method allows quantification of normal and potentially pathologic PB in NICU patients.

Very long apnea events in preterm infants.

Apnea is nearly universal among very low birth weight (VLBW) infants, and the associated bradycardia and desaturation may have detrimental consequences. We describe here very long (>60 s) central apnea events (VLAs) with bradycardia and desaturation, discovered using a computerized detection system applied to our database of over 100 infant years of electronic signals. Eighty-six VLAs occurred in 29 out of 335 VLBW infants. Eighteen of the 29 infants had a clinical event or condition possibly related to the VLA. Most VLAs occurred while infants were on nasal continuous positive airway pressure, supplemental oxygen, and caffeine. Apnea alarms on the bedside monitor activated in 66% of events, on average 28 s after cessation of breathing. Bradycardia alarms activated late, on average 64 s after cessation of breathing. Before VLAs oxygen saturation was unusually high, and during VLAs oxygen saturation and heart rate fell unusually slowly. We give measures of the relative severity of VLAs and theoretical calculations that describe the rate of decrease of oxygen saturation. A clinical conclusion is that very long apnea (VLA) events with bradycardia and desaturation are not rare. Apnea alarms failed to activate for about one-third of VLAs. It appears that neonatal intensive care unit (NICU) personnel respond quickly to bradycardia alarms but not consistently to apnea alarms. We speculate that more reliable apnea detection systems would improve patient safety in the NICU. A physiological conclusion is that the slow decrease of oxygen saturation is consistent with a physiological model based on assumed high values of initial oxygen saturation.

Study of the diagnostic efficacy of real-time optical coherence tomography as an adjunct to unaided visual inspection with acetic acid for the diagnosis of preinvasive and invasive neoplasia of the uterine cervix.

OBJECTIVES: To determine the sensitivity and specificity of optical coherence tomography (OCT) as an adjunct to unaided visual inspection using acetic acid (VIA) in the detection of cervical intraepithelial neoplasia 2 (CIN 2) in a real-time clinical evaluation. BACKGROUND: This clinical study was a prospective cross-sectional comparative trial that screened 1000 patients (aged 30-50 years) in a low-resource setting. Women with abnormal cervical cytology or positive human papillomavirus (HPV) tests were referred for further evaluation including VIA, OCT imaging, colposcopy, and cervical biopsies. METHODS: The VIA diagnoses were coded by quadrant. The OCT was then performed in all VIA-positive areas and at the squamocolumnar junction in all 4 quadrants. All patients were colposcoped; assessed by quadrant with biopsies at 2, 4, 8, and 10 o'clock; all abnormal areas were biopsied; and endocervical curettage was performed. Data were analyzed using generalized estimating equations and logistic regression. RESULTS: Of the 1000 patients, 175 (17.5%) were HPV positive, 93 (9.3%) had abnormal cervical cytology greater than or equal to atypical squamous cells of undetermined significance, and 211 (21.1%) were either HPV positive or had abnormal cytology. The VIA, OCT, colposcopy, and biopsies were completed on 183 (86.7%) of 211 women. For VIA alone, the sensitivity and specificity in detecting lesions greater than or equal to CIN 2 was 43% and 96%. With the addition of OCT, the sensitivity increases to 62% with a specificity of 80%. CONCLUSIONS: With the addition of OCT, the sensitivity of VIA increased in all analyses for the detection of greater than or equal to CIN II, with a loss in specificity. We hope that the potential of this technology will be realized when a computer algorithm is generated to aid in image interpretation.

Diagnostic efficacy of real-time optical coherence tomography in the management of preinvasive and invasive neoplasia of the uterine cervix.

OBJECTIVE: Determine the sensitivity and specificity of optical coherence tomography (OCT) as an adjunct to colposcopy in the detection of cervical intraepithelial neoplasia (CIN) grade 2 or higher in a real-time clinical evaluation. BACKGROUND: Optical coherence tomography (OCT) uses infrared light similar to ultrasound pulse-echo imaging. Image resolution is optimal in the 1-to-3-mm range. This study is the third in our series of OCT investigations and our first real-time clinical trial. The study was conducted at the Peking University Shenzhen Hospital, Shenzhen, China. METHODS: Nonpregnant women 18 years or older with abnormal cervical cytologic findings or a positive high-risk human papillomavirus test result were recruited. Women were assessed; and diagnoses, recorded by cervical quadrant first with colposcopy, followed by colposcopic directed OCT. A biopsy of the abnormal areas was performed. In normal quadrants, biopsy specimens were obtained at the 2-, 4-, 8-, and 10-o'clock positions at the squamocolumnar junction depending on the quadrant. An endocervical curettage was also done. Individual OCT diagnoses were paired with colposcopic impressions and biopsy specimens to assess its role as a paired secondary screen. Data were analyzed using generalized estimating equations to control for correlation within a woman. RESULTS: One thousand two hundred thirty-seven paired diagnoses from 299 women were analyzed. Median age was 36 years. Ninety-six women (8%) had a diagnosis of CIN 2 or higher. Evaluation by quadrant showed that the sensitivity for CIN 2 or higher decreased by adding OCT to colposcopy, but the specificity increased from 83% to 93%. CONCLUSIONS: We continue to try to improve sensitivity by improving the near-infrared light source, decreasing the scan time to 8 frames per second, and using a larger diameter (5 mm) fiberoptic probe with a newly designed application specific probe sheath.