Early optical coherence tomography evaluation of donor-transmitted atherosclerosis and cardiac allograft vasculopathy: insights from a prospective, single-center study

BACKGROUND

The impact of donor transmitted atherosclerosis as assessed by intravascular ultrasound on development and progression of cardiac allograft vasculopathy (CAV) after heart transplantation (HT) remains poorly defined in contemporary practice. In this exploratory analysis, we sought to assess the prognostic role of early qualitative assessment of donor artery morphology using optical coherence tomography (OCT) as a more sensitive imaging modality.

METHODS

HT recipients were prospectively enrolled for baseline OCT imaging of the left anterior descending coronary artery. OCT findings were classified as normal, homogeneous intimal thickening, and advanced plaque characteristics. The endpoint was a composite of cardiac death, myocardial infarction, or new angiographically detectable CAV stratified by the International Society of Heart and Lung Transplantation criteria up to 4 years of follow-up.

RESULTS

A total of 35 patients underwent baseline OCT of whom 51.4% had normal OCT, 14.3% had homogenous plaque, and 34.3% had advanced characteristics. There were no significant differences in baseline demographics between patients with and without normal morphology. During a mean follow-up of 3.3 ± 0.4 years, the endpoint occurred in 11 patients including 1 death, 7 CAV1, 3 CAV2, and 1 CAV3. Kaplan-Meier analysis revealed a significantly higher event rate in patients with advanced characteristics (log-rank p = 0.010). In multivariate analysis, OCT-based plaque morphology was an independent predictor of clinical events (adjusted hazard ratio 4.57, 95% confidence interval 1.50-13.92, p = 0.008) while maximal intimal thickness ≥0.5 mm was not.

CONCLUSIONS

Early qualitative OCT assessment of donor coronary artery morphology appears to be a reliable marker for predicting future cardiovascular events in HT recipients. Our findings warrant more careful study in a larger cohort.

Cardiac Transplantation Using Hearts With Transient Dysfunction: Role of Takotsubo-Like Phenotype

BACKGROUND

The impact of different types of regional wall motion abnormalities (RWMAs), including the Takotsubo syndrome-like (TTS-like) phenotype, on posttransplant outcomes when using donor hearts with transient left ventricular systolic dysfunction (LVSD) is unknown. We evaluated the prevalence, clinical characteristics, and prognostic association of different RWMAs including TTS-like hypokinesis and posttransplant outcomes when using donor hearts with transient LVSD.

METHODS

From all adult (≥18 years) heart transplants in United Network of Organ Sharing between January 2007 and September 2015, we identified 472 donor hearts with improving or transient LVSD, defined as left ventricular ejection fraction ≤ 40% on initial transthoracic echocardiogram (TTE) that improved to ≥50% on follow-up TTE during donor evaluation. These improved LVSD donors were then subdivided into 3 groups based on RWMAs on the initial TTE, TTS-like (49, 10.38%), non-TTS RWMAs (74, 15.68%), and diffuse global hypokinesis (349, 73.94%), and compared for baseline characteristics and posttransplant outcomes with follow up until June 2018.

RESULTS

Donors with TTS-like LVSD were older and more likely to be female. The type of RWMA on initial TTE (including TTS-like) of transient LVSD donor hearts was not associated with 1-year or 5-year posttransplant mortality. Posttransplant functional status scores of recipients (at 1 year) and donor left ventricular ejection fraction (at median follow-up of 3.6 years) improved in all 3 subgroups. Rates of stroke or pacemaker predischarge were also similar.

CONCLUSIONS

In the largest analysis of transplanted donor hearts with transient LVSD, 1 in 4 had RWMAs on the initial TTE, but this was not associated with adverse posttransplant outcomes. Donor hearts with initial LVSD should be pursued irrespective of TTS-like hypokinesis or other RWMAs.

Outcomes of heart transplantation in patients with human immunodeficiency virus

Human immunodeficiency virus-positive (HIV+) patients are not routinely offered heart transplantation (HT) due to lack of adequate outcomes data. Between January 2004 and March 2017, we identified 41 adult (≥18 years) HT recipients with known HIV+ serostatus at the time of transplant in UNOS and evaluated post-HT outcomes. Overall, Kaplan-Meier (KM) estimates of survival at 1 and 5 years were 85.9% and 77.3%, respectively, with no significant difference in bridge-to-transplant ventricular-assist device (BTT-VAD, n = 22) and no-BTT-VAD (n = 19). KM estimates of cardiac allograft vasculopathy (CAV) and malignancy at 5 years were 32% and 19%, respectively. Using propensity scores, 41 HIV+ HT recipients were matched to 41 HIV- HT recipients for idiopathic dilated-cardiomyopathy; and there was no significant difference in post-HT survival up to 5 years. Furthermore, only 24 centers in the United States had performed HIV+ HT during the study period, indicating that >80% of HT centers in the United States had not performed any HIV+ HT. In a cohort representative of the current status of HIV+ HTs in the United States, we found that the posttransplant survival was excellent and rates of CAV and malignancy were comparable to the overall HT population. These results should encourage greater number of centers to offer HT to suitable HIV+ candidates and help reduce unequal access to HT for HIV+ patients.

Spontaneous coronary artery dissection in a postpartum e-cigarette smoker

Spontaneous coronary artery dissection (SCAD) is a rare but lethal cause of acute coronary syndrome that occurs in young women during the peripartum/postpartum periods. We present a case of a 41-year-old woman with no significant medical history, but was a habitual e-cigarette smoker who presented with atypical chest pain 2 weeks after an uncomplicated delivery while breast feeding. The patient was found to have elevated cardiac enzymes and ST segment elevations in the anterior leads. An urgent cardiac catheterisation was performed, which revealed dissection and occlusion of the left anterior descending artery, and a drug-eluting stent was placed that resulted in the resolution of chest pain. Physiological changes during the postpartum period may be linked to an increased risk of developing SCAD.¹ In addition, e-cigarette smoking is associated with increased oxidative stress and sympathetic activity, which may predispose patients to an increased risk of acute coronary syndrome.

Asian Americans have greater prevalence of metabolic syndrome despite lower body mass index

Objective

To examine the relationship between body mass index and metabolic syndrome for Asian Americans and non-Hispanic Whites, given that evidence shows racial/ethnic heterogeneity exists in how body mass index predicts metabolic syndrome.

Research Design and Methods

Electronic health records of 43 507 primary care patients aged 35 years and older with self-identified race/ethnicity of interest (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese, or non-Hispanic White) were analyzed in a mixed-payer, outpatient-focused healthcare organization in the San Francisco Bay Area.

Results

Metabolic syndrome prevalence is significantly higher in Asians compared to non-Hispanic Whites for every body mass index category. For women at the mean age of 55 and body mass index of 25 kg/m², the predicted prevalence of metabolic syndrome is 12% for non-Hispanic White women compared to 30% for Asians; similarly for men, the predicted prevalence of metabolic syndrome is 22% for non-Hispanic Whites compared to 43% of Asians. Compared to non-Hispanic White women and men with a body mass index of 25 kg/m², comparable prevalence of metabolic syndrome was seen at body mass index of 19.6 kg/m² for Asian women and 19.9 kg/m² for Asian men. A similar pattern was seen in disaggregated Asian subgroups.

Conclusions

Despite lower body mass index values and lower prevalence of overweight/obesity than non-Hispanic Whites, Asian Americans have higher rates of metabolic syndrome over the range of body mass index. Our results indicate that body mass index ranges for defining overweight/obesity in Asian populations should be lower than for non-Hispanic Whites.

Detection of disease recurrence in differentiated thyroid cancer

Thyroid cancer is the most common malignancy of the endocrine system, with an incidence that has been increasing for several decades. Differentiated thyroid carcinomas, which account for more than 90% of thyroid cancers, are generally indolent tumors with excellent long-term prognosis. However, the recurrence rates of differentiated thyroid cancers are high. In recognition of the growing incidence of thyroid cancer and its unfavorable risk of recurrence, several management guidelines have been established in order to effectively diagnose and treat initial and recurrent diseases at an early stage. Furthermore, the guidelines acknowledge the improvements in diagnostic modalities that have brought about a major paradigm shift in the management of thyroid cancer and surveillance for recurrence. This review will discuss the most current and advanced strategies for detection of recurrent differentiated thyroid cancer.

Role of oral anti-diabetic agents in modifying cardiovascular risk factors

Patients with type 2 diabetes have an increased risk for cardiovascular disease (CVD) and it accounts for up to 80% of excess deaths in these patients. It has been recognized that type 2 diabetes is associated with an increased prevalence of CVD risk factors, including hypertension, dyslipidemia, microalbuminuria, and altered hemostasis. The benefit of cardiovascular protection can only be partially explained by controlling hyperglycemia. Some of the oral agents used to treat hyperglycemia significantly modify other cardiovascular risk factors. This article will review oral agents used to treat type 2 diabetes and their effects on modifying CVD risk factors.

CT guided pararectal seed implant for localized prostate cancer: a preliminary report

One hundred and fifty-two patients were treated with CT guided pararectal prostate seed implant (CPSI) alone or in combination with external-beam 3D conformal radiation therapy (EB3DRT) and Androgen Blockage Hormone Therapy (HT). A decrease and normalization in PSA values was seen following treatment in all groups. However, a better therapeutic response was observed in the individuals that received CPSI and EB3DRT with hormone therapy.

Identification of 4-coumarate:coenzyme A ligase (4CL) substrate recognition domains

4-coumarate:CoA ligase (4CL), the last enzyme of the general phenylpropanoid pathway, provides precursors for the biosynthesis of a large variety of plant natural products. 4 CL catalyzes the formation of CoA thiol esters of 4-coumarate and other hydroxycinnamates in a two step reaction involving the formation of an adenylate intermediate. 4 CL shares conserved peptide motifs with diverse adenylate-forming enzymes such as firefly luciferases, non-ribosomal peptide synthetases, and acyl:CoA synthetases. Amino acid residues involved in 4 CL catalytic activities have been identified, but domains involved in determining substrate specificity remain unknown. To address this question, we took advantage of the difference in substrate usage between the Arabidopsis thaliana 4 CL isoforms At4CL1 and At4CL2. While both enzymes convert 4-coumarate, only At4CL1 is also capable of converting ferulate. Employing a domain swapping approach, we identified two adjacent domains involved in substrate recognition. Both substrate binding domain I (sbd I) and sbd II of At4CL1 alone were sufficient to confer ferulate utilization ability upon chimeric proteins otherwise consisting of At4CL2 sequences. In contrast, sbd I and sbd II of At4CL2 together were required to abolish ferulate utilization in the context of At4CL1. Sbd I corresponds to a region previously identified as the substrate binding domain of the adenylation subunit of bacterial peptide synthetases, while sbd II centers on a conserved domain of so far unknown function in adenylate-forming enzymes (GEI/LxIxG). At4CL1 and At4CL2 differ in nine amino acids within sbd I and four within sbd II, suggesting that these play roles in substrate recognition.

Transplanted neuroblasts differentiate appropriately into projection neurons with correct neurotransmitter and receptor phenotype in neocortex undergoing targeted projection neuron degeneration

Reconstruction of complex neocortical and other CNS circuitry may be possible via transplantation of appropriate neural precursors, guided by cellular and molecular controls. Although cellular repopulation and complex circuitry repair may make possible new avenues of treatment for degenerative, developmental, or acquired CNS diseases, functional integration may depend critically on specificity of neuronal synaptic integration and appropriate neurotransmitter/receptor phenotype. The current study investigated neurotransmitter and receptor phenotypes of newly incorporated neurons after transplantation in regions of targeted neuronal degeneration of cortical callosal projection neurons (CPNs). Donor neuroblasts were compared to the population of normal endogenous CPNs in their expression of appropriate neurotransmitters (glutamate, aspartate, and GABA) and receptors (kainate-R, AMPA-R, NMDA-R. and GABA-R), and the time course over which this phenotype developed after transplantation. Transplanted immature neuroblasts from embryonic day 17 (E17) primary somatosensory (S1) cortex migrated to cortical layers undergoing degeneration, differentiated to a mature CPN phenotype, and received synaptic input from other neurons. In addition, 23.1 +/- 13.6% of the donor-derived neurons extended appropriate long-distance callosal projections to the contralateral S1 cortex. The percentage of donor-derived neurons expressing appropriate neurotransmitters and receptors showed a steady increase with time, reaching numbers equivalent to adult endogenous CPNs by 4-16 weeks after transplantation. These results suggest that previously demonstrated changes in gene expression induced by synchronous apoptotic degeneration of adult CPNs create a cellular and molecular environment that is both permissive and instructive for the specific and appropriate maturation of transplanted neuroblasts. These experiments demonstrate, for the first time, that newly repopulating neurons can undergo directed differentiation with high fidelity of their neurotransmitter and receptor phenotype, toward reconstruction of complex CNS circuitry.

Fuzzy assessment of sleep-disordered breathing during continuous positive airway pressure therapy

We propose a new method of quantifying sleep-disordered breathing (SDB) for the purpose of automating continuous positive airway pressure (CPAP) titration. Our algorithm, based on fuzzy logic, emulates the less-than-crisp kind of decision-making generally employed at the human level. Three input variables were first derived on a breath-by-breath basis from respiratory airflow measurements. These were: (1) the relative duration of inspiratory flow limitation in each breath; (2) the degree of hypopnea relative to the past 15 breaths; and (3) the intensity of snoring. Using these descriptors as inputs, our fuzzy inference algorithm produced a "severity index" (SI) quantifying the degree of SDB. Severity index was determined in CPAP titration procedures conducted on one normal snorer and 12 patients with moderate-to-severe obstructive sleep apnea. SI computed over the last 6 minutes of each CPAP level was compared against other more-conventional indices of SDB, such as total pulmonary resistance (RL), the number of apneas and hypopneas (NAH), and the number of arousals (NAr). In all but one of the subjects, the correlation coefficients for SI vs each of RL, NAH, and NAr were significantly different from zero, but not different from each other. The group correlation coefficients for SI vs RL, NAH, and NAr were 0.89, 0.86, and 0.87, respectively, demonstrating that SI accurately quantifies SDB. SI collapses multiple features of the airflow pattern into a single index and, therefore, may be useful as a "feedback" variable for the automatic control of CPAP therapy.

Requirement for Brn-3c in maturation and survival, but not in fate determination of inner ear hair cells

Mutations in the POU domain gene Brn-3c causes hearing impairment in both the human and mouse as a result of inner ear hair cell loss. We show here that during murine embryogenesis, Brn-3c is expressed in postmitotic cells committed to hair cell phenotype but not in mitotic progenitors in the inner ear sensory epithelium. In developing auditory and vestibular sensory epithelia of Brn-3c−/− mice, hair cells are found to be generated and undergo initial differentiation as indicated by their morphology, laminar position and expression of hair cell markers, including myosins VI and VIIa, calretinin and parvalbumin. However, a small number of hair cells are anomalously retained in the supporting cell layer in the vestibular sensory epithelia. Furthermore, the initially differentiated hair cells fail to form stereociliary bundles and degenerate by apoptosis in the Brn-3c−/− mice. These data indicate a crucial role for Brn-3c in maturation, survival and migration of hair cells, but not in proliferation or commitment of hair cell progenitors.

Ventilatory dynamics of transient arousal in patients with obstructive sleep apnea

The hyperpnea that accompanies arousal at the end of obstructive apnea is believed to be due to the progressive build-up in chemical drive during the apnea and a state-related decrease in upper airway resistance. We postulated the existence of a third component: a state-related transient increase in neural drive to the ventilatory pump muscles. To quantify this contribution, we measured the ventilatory response to arousal (VRA) in eight patients with obstructive sleep apnea (OSA) during continuous positive airway pressure (CPAP) therapy, applied at individually titrated levels. CPAP application reduced total pulmonary resistance (RL) to approximately normal levels, stabilizing ventilation and sleep state. Transient arousal from stage 2 sleep was induced using 5-sec tones (60-90 dB). Mean inspiratory flow increased above control on the second and third post-arousal breaths (P < 0.05), with a peak increase of 7.8 +/- 2.9 L/min while the accompanying changes in RL were significant. The time-course of VRA measured in three normal subjects under CPAP was similar to that observed in the OSA patients. However, elimination of CPAP prolonged the VRA time-course. Taken together, these findings demonstrate that: (1) during arousal, the increase in state-related neural respiratory drive is short-lived but not substantial; and (2) the resulting VRA time-course is shaped by the dynamics of the upper airway response to arousal.

Novel genes expressed in the chick otocyst during development: identification using differential display of RNA

Differential display of mRNA is a technique that enables the researcher to compare genes expressed in two or more different tissues or in the same tissue or cell under different conditions. The method is based on polymerase chain reaction amplification and comparison of specific subsets of mRNA. We have used this method to clone partial complementary DNAs (cDNAs; amplicons) for genes expressed in the otocyst in order to identify genes that may be involved in development of the inner ear. A full length cDNA was isolated from an embryonic quail head library with an amplicon (KH121) obtained from the otocyst. This avian cDNA encoded a novel, 172-amino acid acidic protein and detected a major transcript of ca 0.8 kb in RNA from chick embryos and several neonatal chick tissues. The full length avian cDNA had high sequence identity to several human cDNAs (expressed sequence tags) from human fetal tissues, including cochlea, brain, liver/spleen and lung, and from placenta. The human homologue of the avian gene encoded a protein that was 183 amino acids long and had 75.6% amino acid sequence identity to the avian protein. These results identified both the avian and human homologues of an evolutionarily conserved gene encoding a small acidic protein of unknown function; however, expression of this gene was not restricted to otocysts.

Complete cDNAs for CDC42 from chicken cochlea and mouse liver

CDC42 is a member of the ras superfamily of small GTP-binding proteins that are related through the highly conserved GTP-binding domain and are involved in signal transduction pathways. Two full-length CDC42 cDNAs have been isolated: a 2148-bp chick cochlea cDNA and a 2063-bp mouse liver cDNA. Each encodes a CDC42 protein of 191 amino acids. The avian CDC42 protein differs from the mouse at only one amino acid residue, a Thr for a Ser at position 185. Both CDC42 proteins are more similar to the ubiquitous human isoform originally isolated from placenta than to the isoform isolated from fetal brain. Using a probe from the 3' UTR of the mouse liver CDC42 cDNA, we demonstrated that the mouse gene is expressed in all tissues examined. Southern blot analysis of a mouse inter-specific backcross with this gene-specific probe identified at least three CDC42-like (Cdc42l) genes in the mouse genome. Cdc42l1 was mapped to distal mouse Chromosome 4, near Cappb1. Cdc42l2 mapped more proximal on Chromosome 4, whereas Cdc42l3 mapped to the X Chromosome.

Identification of genes expressed after noise exposure in the chick basilar papilla

We used differential display of mRNA, a method based on reverse transcriptase-PCR, to identify genes whose expression increases in response to acoustic trauma in the chick basilar papilla. Identifying these genes would provide insight into processes involved in repair of the damaged epithelium or in hair cell regeneration. We compared mRNA from the basilar papilla of normal chicks, from chicks exposed to an octave band noise (center frequency: 1.5 kHz) presented at 118 dB for 6 h, and from chicks exposed to noise and allowed to recover for 2 days. Thus far, we have identified 70 bands that appear to be differentially displayed on DNA sequencing gels; approximately 40 of these bands have been subcloned and sequenced. DNA sequences were compared with sequences in the GenBank database to identify genes with significant (70-85%) sequence identity to known genes. Chick cDNAs identified included: the parathyroid hormone-related protein, an immediate early gene; the delta-subunit of the neuronal-specific Ca2+/calmodulin-regulated protein kinase II; and the GTP-binding protein CDC42, a member of the ras superfamily of G proteins. A fourth cDNA had 84% sequence identity to an uncharacterized human cDNA (expressed sequence tag), indicating that this is a novel gene. Slot-blot hybridization analysis of these cDNAs probed with labeled DNA generated from mRNA from each experimental group indicated higher levels of mRNA for each of these four genes after noise exposure. These results indicate the potential involvement of both Ca2+/calmodulin-mediated signaling and GTPase cascades in the response to noise damage and during hair cell regeneration in the chick basilar papilla.

Ventilatory dynamics during transient arousal from NREM sleep: implications for respiratory control stability

The polysomnographic and ventilatory patterns of nine normal adults were measured during non-rapid-eye-movement (NREM) stage 2 sleep before and after repeated administrations of a tone (40-72 dB) lasting 5 s. The ventilatory response to arousal (VRA) was determined in data sections showing electrocortical arousal following the start of the tone. Mean inspiratory flow and tidal volume increased significantly above control levels in the first seven breaths after the start of arousal, with peak increases (64.2% > control) occurring on the second breath. Breath-to-breath occlusion pressure 100 ms after the start of inspiration showed significant increases only on the second and third postarousal breaths, whereas upper airway resistance declined immediately and remained below control for > or = 7 consecutive breaths. These results suggest that the first breath and latter portion of the VRA are determined more by upper airway dynamics than by changes in the neural drive to breathe. Computer model simulations comparing different VRA time courses show that sustained periodic apnea is more likely to occur when the fall in the postarousal increase in ventilation is more abrupt.

Estimation of dynamic chemoresponsiveness in wakefulness and non-rapid-eye-movement sleep

We developed a method for quantifying dynamic chemoresponsiveness on the basis of the ventilatory response to pseudorandom binary CO2 stimulation. The dynamic chemoreflex gain (GD) and effective time delay (TDeff) relating breath-to-breath fluctuations in alveolar PCO2 to ventilation were evaluated at frequencies between 0 and 0.05 Hz. Application of the method to simulated "data" showed that estimation errors in GD and TDeff were most likely to be minimized in the range of 0.01-0.03 Hz, corresponding to periodicities of 30-100 s. Estimation of TDeff was generally more susceptible to error than that of GD because of the limited time resolution of the breath-by-breath measurements. In eight awake normal adults, we compared estimates of GD derived from the pseudorandom binary CO2 stimulation test with peripheral and central hypercapnic sensitivities deduced from single-breath and Read rebreathing measurements in the same subject. GD at 0.02 Hz was highly correlated with peripheral hypercapnic sensitivity but poorly correlated with central hypercapnic sensitivity, underscoring the importance of the peripheral chemoreflexes in mediating ventilatory responses to phasic stimuli. Application of the procedure to a different group of 10 healthy volunteers during wakefulness and stage 2 sleep showed decreases in GD in 8 subjects but increases in 2 subjects. However, for the group as a whole, GD and TDeff did not change significantly between wakefulness and sleep. The proposed method may provide information more pertinent to periodic breathing than traditional CO2 response tests do, since the chemoreflex responses to phasic variations in blood gases are likely to be important in determining ventilatory control during sleep.