Elimination of virus-like particles reduces protein aggregation and extends replicative lifespan in Saccharomyces cerevisiae

A major consequence of aging and stress, in yeast to humans, is an increased accumulation of protein aggregates at distinct sites within the cells. Using genetic screens, immunoelectron microscopy, and three-dimensional modeling in our efforts to elucidate the importance of aggregate annexation, we found that most aggregates in yeast accumulate near the surface of mitochondria. Further, we show that virus-like particles (VLPs), which are part of the retrotransposition cycle of Ty elements, are markedly enriched in these sites of protein aggregation. RNA interference-mediated silencing of Ty expression perturbed aggregate sequestration to mitochondria, reduced overall protein aggregation, mitigated toxicity of a Huntington's disease model, and expanded the replicative lifespan of yeast in a partially Hsp104-dependent manner. The results are in line with recent data demonstrating that VLPs might act as aging factors in mammals, including humans, and extend these findings by linking VLPs to a toxic accumulation of protein aggregates and raising the possibility that they might negatively influence neurological disease progression.

Dynamic calcium-mediated stress response and recovery signatures in the fungal pathogen, Candida albicans

IMPORTANCE

Intracellular calcium signaling plays an important role in the resistance and adaptation to stresses encountered by fungal pathogens within the host. This study reports the optimization of the GCaMP fluorescent calcium reporter for live-cell imaging of dynamic calcium responses in single cells of the pathogen, Candida albicans, for the first time. Exposure to membrane, osmotic or oxidative stress generated both specific changes in single cell intracellular calcium spiking and longer calcium transients across the population. Repeated treatments showed that calcium dynamics become unaffected by some stresses but not others, consistent with known cell adaptation mechanisms. By expressing GCaMP in mutant strains and tracking the viability of individual cells over time, the relative contributions of key signaling pathways to calcium flux, stress adaptation, and cell death were demonstrated. This reporter, therefore, permits the study of calcium dynamics, homeostasis, and signaling in C. albicans at a previously unattainable level of detail.

Developmental biology-inspired tissue engineering by combining organoids and 3D bioprinting

Very few tissue-engineered constructs could achieve the desired results in human clinical trials. The main reason is their inability to recapitulate the cellular conformation, biological, and mechanical functions of the native tissue. Here, we highlight the future avenues of tissue regeneration combining developmental biology, organoids, and 3D bioprinting. A deep mechanistic insight into the embryonic level and recapitulating them would be the most promising strategy in next-generation tissue engineering. Rather than focusing on the adult tissue features, the latest developmental re-engineering strategies replicate the developmental phases of tissue development. Integrating developmental re-engineering with 3D bioprinting can regulate several signaling pathways. This would further help to fabricate mini-organ constructs for transplantation or in vitro screening of drugs using an organ-on-a-chip platform.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

In Vitro and Ectopic In Vivo Studies toward the Utilization of Rapidly Isolated Human Nasal Chondrocytes for Single-Stage Arthroscopic Cartilage Regeneration Therapy

Nasal chondrocytes (NCs) have a higher and more reproducible chondrogenic capacity than articular chondrocytes, and the engineered cartilage tissue they generate in vitro has been demonstrated to be safe in clinical applications. Here, we aimed at determining the feasibility for a single-stage application of NCs for cartilage regeneration under minimally invasive settings. In particular, we assessed whether NCs isolated using a short collagenase digestion protocol retain their potential to proliferate and chondro-differentiate within an injectable, swiftly cross-linked and matrix-metalloproteinase (MMP)-degradable polyethylene glycol (PEG) gel enriched with human platelet lysate (hPL). NC-hPL-PEG gels were additionally tested for their capacity to generate cartilage tissue in vivo and to integrate into cartilage/bone compartments of human osteochondral plugs upon ectopic subcutaneous implantation into nude mice. NCs isolated with a rapid protocol and embedded in PEG gels with hPL at low cell density were capable of efficiently proliferating and of generating tissue rich in glycosaminoglycans and collagen II. NC-hPL-PEG gels developed into hyaline-like cartilage tissues upon ectopic in vivo implantation and integrated with surrounding native cartilage and bone tissues. The delivery of NCs in PEG gels containing hPL is a feasible strategy for cartilage repair and now requires further validation in orthotopic in vivo models.

Impact of new-onset left bundle branch block on clinical and echocardiographic outcomes after TAVR with SAPIEN-3 valve

Background

New left bundle branch block (LBBB) is a common finding after transcatheter aortic valve replacement (TAVR) that can result in worse outcomes after TAVR. We aim to investigate the impact of new-onset LBBB after TAVR using the SAPIEN-3 (S3) valve.

Methods

Consecutive patients who underwent transfemoral-TAVR with S3 valve between April 2015 and December 2018 were included. Exclusion criteria included pre-existing LBBB, right bundle branch block, left anterior hemiblock, left posterior hemiblock, wide QRS ≥120 msec, prior permanent pacemaker (PPM), and non-transfemoral access.

Results

Among 612 patients, 11.4% developed new-onset LBBB upon discharge. Implantation depth was the only predictor of new-onset LBBB (OR 1.294; 95% CI 1.121–1.493; p<0.001). The median (IQR) length of stay was longer with new-onset LBBB [3 (2–5) days vs. 2 (1–3) days; p<0.001]. New-onset LBBB was associated with higher thirty-day PPM requirement (18.6% vs. 5.4%; p<0.001) including those implanted after discharge (4.3% vs. 0.9%; p=0.02). There was no difference in 3-year all-cause mortality between both groups (30.9% vs. 30.6%; log-rank p=0.829). Further, new-onset LBBB was associated with lower left ventricular ejection fraction (LVEF) at both 30 days (55.9±11.4% vs. 59.3±9%; p=0.026) and 1 year (55±12% vs. 60.1±8.9%; p=0.002) despite no differences at baseline. These changes were still present when we stratified patients according to baseline LVEF (≥50% or <50%). We also noted higher mean LV end-diastolic volume index (51.4±18.6 vs. 46.4±15.1 ml/m2; p=0.036), and LV end-systolic volume index (23.2±14.1 vs. 18.9±9.7 ml/m2; p=0.009) with new-onset LBBB at 1 year. Lastly, there were significantly higher rates of heart failure readmissions at 1 year with new-onset LBBB (10.7% vs. 4.4%; log-rank p=0.033).

Conclusion

Among our cohort of S3 recipients, new-onset LBBB was associated with higher PPM requirement, worse LVEF, higher LV volumes and increased risk of heart failure hospitalizations. However, it did not affect mortality in the short-to-intermediate post-TAVR period.

Funding Acknowledgement

Type of funding sources: None. Figure 1. All-cause Survival

Impact of doppler velocity index after transcatheter aortic valve replacement using Sapien-3 valve – a single centre experience

Background

Little is known about the hemodynamic performance of Edwards Sapien-3 (S3) valve after Transcatheter Aortic Valve Replacement (TAVR). Doppler velocity index (DVI) is a better indicator of prosthetic valve function as it is independent of valve size and flow, unlike mean gradient and peak velocity which are flow-dependent.

Methods

In this study, we compare outcomes based on differences in DVI among a consecutive series of patients who underwent S3 TAVR between April 2015 and December 2018. Our institutional review board approved the study and informed consents were obtained from the subjects.

Results

Among 921 patients who had follow-up echocardiograms within 30 days after TAVR, 60.8% had DVI ≤0.5, while 39.2% had DVI >0.5. The median 30-day DVI was 0.47 with a standard deviation of 0.11 and mean 0.49 and interquartile range 0.41–0.55. The baseline clinical and procedural characteristics were similar between both groups with the exception of less post-dilation (36.8% vs. 47.4%; p=0.001) and greater implantation depth (2.59±1.99 vs. 2.31±1.9mm; p=0.031) with DVI ≤0.5. The rates of aortic valve calcification, pre dilation, pre-TAVR aortic regurgitation (AR) were similar. At baseline, there were no differences between both groups in mean or peak gradients or aortic velocity time integral (VTI). At 1 year, mean gradients were higher with DVI ≤0.5 (12.7±5.6 vs. 11.1±4.6 mmHg; p=0.001). DVI ≤0.5 was associated with higher peak gradients (24.2±10.2 vs. 21.4±8.7 mmHg; p=0.002), and aortic VTI (51.4±13.5 vs. 46.8±12.2 cm; p<0.001) at 1 year, especially with the 26mm and 29mm prostheses. Compared with DVI>0.5 group, patients in DVI<0.5 group had lower baseline left ventricular ejection fraction (LVEF) (54.5±12.2% vs. 58.9±11.2%; p<0.001), higher left ventricular end-diastolic volume index (LVEDVi) (54.3±20.9 vs. 49.4±17.4 ml/m2; p=0.001), higher LV end-systolic volume index (LVESVi) (25.2±16.5 vs. 21.3±12.7 ml/m2; p=0.001), and similar LV mass index (110.7±31.9 vs. 106.9±32.7 g/m2; p=0.134). 1-year mortality rates among patients who had DVI ≤0.5 compared to DVI >0.5 were lower (6.6% vs. 10.6%; log-rank p=0.033), however no difference was noted at both 2 years (17.3% vs. 20.1%; log-rank p=0.151), and 3 years after TAVR (30.7% vs. 31.2%; log-rank p=0.333).

Conclusions

DVI<0.5 was associated with higher peak gradients and lower baseline LVEF. DVI <0.5 group patients had lower 1-year mortality but similar mortality at 2 and 3-years of follow up.

Funding Acknowledgement

Type of funding sources: None. Figure 1. All-cause SurvivalFigure 2. Hemodynamic Data

Impact of pacing-related differences on clinical and echocardiographic outcomes after TAVR with SAPIEN-3 valve

Background

Data regarding the impact of pacing on outcomes after transcatheter aortic valve replacement (TAVR) is evolving especially with regards to pre-existing PPM. We examined the impact of new and prior PPM on clinical and hemodynamic outcomes after SAPIEN-3 (S3) TAVR.

Methods

Consecutive patients who underwent transfemoral-TAVR using S3 valve between April 2015 and December 2018 at our Clinic were included.

Results

Among 1028 patients, 10.2% required new PPM within 30 days, while 14% had pre-existing PPM. The presence of either prior or new PPM had no impact on 3-year mortality (log-rank p=0.6), or 1-year major adverse cardiac and cerebrovascular event (MACCE) (log-rank p=0.65). New PPM was associated with lower left ventricular ejection fraction (LVEF) at both 30 days (54.4±11.3% vs. 58.4±10.1%; p=0.001), and 1 year (54.2±12% vs. 59.1±9.9%; p=0.009) compared to no PPM. Similarly, prior PPM was associated with worse LVEF at 30 days (53.6±12.3%; p<0.001) and 1 year (55.5±12.1%; p=0.006) compared to no PPM. Interestingly, new PPM was associated with lower 1-year mean gradient (11.4±3.8 vs. 12.6±5.6 mmHg; p=0.04), and peak gradient (21.3±6.5 vs. 24.1±10.4 mmHg; p=0.01) despite no baseline differences. Prior PPM was also associated with lower 1-year mean gradient (10.3±4.4 mmHg; p=0.001), and peak gradient (19.4±8 mmHg; p<0.001), and higher doppler velocity index (0.51±0.12 vs. 0.47±0.13; p=0.039). Moreover, 1-year LV end-systolic volume (LVESVi) was higher with new (23.2±16.1 vs. 20±10.8 ml/m2; p=0.038), and prior PPM (24.5±19.7; p=0.038) compared to no PPM. Prior PPM was associated with higher moderate-to-severe tricuspid regurgitation (35.3% vs. 17.7%; p<0.001). There were no differences with regards to the rest of the studied echocardiographic outcomes at 1 year.

Conclusion

In this S3 cohort, new and prior PPM did not affect 3-year mortality or 1-year MACCE, however they were associated with worse LVEF, higher LVESVi and lower mean and peak gradients on follow-up compared to no PPM.

Funding Acknowledgement

Type of funding sources: None. Figure 1. All-cause Survival

Outcomes of transfemoral-transcatheter aortic valve replacement with Sapien-3 valve in liver cirrhosis patients

Background

Little is known about the outcomes of liver cirrhosis patients with severe aortic stenosis (AS) who undergo transcatheter aortic valve replacement (TAVR).

Methods

We undertook a retrospective analysis of consecutive patients with severe symptomatic AS who underwent transfemoral-TAVR with Sapien-3 valve at our Clinic between April 2015 and December 2018, yielding 32 patients with liver cirrhosis on imaging including ultrasound and/or computed tomography. Their baseline characteristics, procedural and long-term outcomes after TAVR with the non-cirrhotic group were compared, along with their management strategies as per the hepatology team.

Results

Among 1028 patients, 32 were assigned to the cirrhosis, and 996 were assigned to the non-cirrhosis (control) group. Compared with the control group cirrhotic patients were slightly younger in age (74.5 vs 81.2 years), had a slightly higher BMI (31.3 vs 29.3), and had a higher incidence of prior history of myocardial infarction (38% vs 33%). Baseline variables including the history of smoking, hypertension, diabetes, and atrial fibrillation were comparable in both groups. Among cirrhotic patients (n=32), the most common etiologies were non-alcoholic steatohepatitis (NASH) (37.5%), Alcoholism (18.75%), and Hepatitis C (12.5%). The mean MELD-NA score was 11.8 and 67% of patients were Child PUGH Class A and 33% were Child PUGH Class B and all patients had a Child PUGH score of ≥5. 53% of patients (n=17) in the cirrhosis group were evaluated by Hepatology and 12.5% (n=4) were evaluated for a liver transplant but only 1 patient had a liver transplant post-TAVR. Compared with the control group cirrhotic patients had similar 1-year mortality (12% vs 12%, p=1), had a lower rate of 30-day new pacemaker post tavr (6% vs 9% p=0.85), had a higher rate of 1-year readmission for heart failure (12% vs 5% p=0.12) and similar 1-year major adverse cardiac and cerebrovascular event (MACCE) rate (15% vs 14% p=0.98)

Conclusion

Patients with severe AS undergoing TAVR with concomitant liver cirrhosis demonstrate comparable outcomes compared with their non- cirrhotic counterparts. NASH followed by alcoholic cirrhosis was found to be most common etiology.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Seroprevalence of SARS-CoV-2 among potential convalescent plasma donors and analysis of their deferral pattern: Experience from tertiary care hospital in western India

Background and objectives

Seroprevalence estimation of COVID-19 is quite necessary for controlling the transmission of SARS-CoV-2 infection. Seroprevalence rate in recovered COVID-19 patients help us to identify individual with anti-SARS-CoV-2 antibodies and its protective nature. The objective of present study was to evaluate seroprevalence of SARS-CoV-2 among potential convalescent plasma donors and analysis of their deferral reasons.

Materials and methods

A total 400 potential convalescent plasma donors were enrolled over five-month period for this prospective study. Inclusion criteria were lab confirmed COVID-19 recovered patients and 14 days of symptoms free period. All prospective plasmapheresis donors were tested for IgG SARS-CoV-2 antibody through chemiluminescent microparticle immunoassay, CBC, serum protein, blood grouping along with other required test for normal blood donation as per Drugs & Cosmetics Act. After pre donation testing and medical examination if donor was found to be ineligible for plasmapheresis was deferred. Seroprevalence rate was calculated by positive IgG antibody test results among the potential plasma donors.

Results

Seroprevalence rate was 87% for IgG SARS-CoV-2 antibodies in prospective convalescent plasma donors (recovered COVID-19 patients). There was no significant difference in seroprevalence rate between different sub-groups with respect to gender, age, blood groups, Rh factor, mode of treatment, day of Ab testing and repeat plasma donation. Most common reason for their deferral was absent IgG SARS-CoV-2 antibodies (13%) followed by absenteeism of eligible screen donors (6.7%), low Hb (1.7%) and poor veins for plasmapheresis (1.7%). Till five-month study period none of the plasmapheresis develop symptoms of reinfection with COVID-19.

Conclusion

In all, 13% recovered patients did not develop IgG antibodies after SARS-CoV-2 infection. SARS-CoV-2 IgG antibodies persist for quite some time and are protective against reinfection. More long-term serology studies are needed to understand better antibody response kinetics and duration of persistence of IgG antibodies.

Blockage of bone morphogenetic protein signalling counteracts hypertrophy in a human osteoarthritic micro-cartilage model

Bone morphogenetic protein (BMP) signalling plays a significant role during embryonic cartilage development and has been associated with osteoarthritis (OA) pathogenesis, being in both cases involved in triggering hypertrophy. Inspired by recent findings that BMP inhibition counteracts hypertrophic differentiation of human mesenchymal progenitors, we hypothesized that selective inhibition of BMP signalling would mitigate hypertrophic features in OA cartilage. First, a 3D in vitro OA micro-cartilage model was established using minimally expanded OA chondrocytes that was reproducibly able to capture OA-like hypertrophic features. BMP signalling was then restricted by means of two BMP receptor type I inhibitors, resulting in reduction of OA hypertrophic traits while maintaining synthesis of cartilage extracellular matrix. Our findings open potential pharmacological strategies for counteracting cartilage hypertrophy in OA and support the broader perspective that key signalling pathways known from developmental processes can guide the understanding, and possibly the mitigation, of adult pathological features.

Abstract P1-13-05: Efficacy and safety of eflapegrastim confirmed in reducing severe neutropenia in breast cancer patients treated with myelosuppressive chemotherapy in the second Phase 3 randomized controlled multinational trial compared to pegfilgrastim (RECOVER trial)

Background:

Eflapegrastim is a novel investigational biologic comprised of recombinant human G-CSF covalently linked to the human immunoglobulin G4FC fragment using proprietary LAPSCOVERY™ technology with potentially unique distribution to areas rich in FcRn receptors. RECOVER is the second Phase 3 study to investigate the non-inferiority (NI) of eflapegrastim to pegfilgrastim in patients receiving chemotherapy for breast cancer. The first Phase 3 study, ADVANCE, has demonstrated the non-inferiority of eflapegrastim comparing to pegfilgrastim in the duration of severe neutropenia (DSN) in breast cancer patients receiving docetaxel and cyclophosphamide (TC) and was previously published at ASCO 2018 meeting.

TrialDesign:

Patients with Stage I to Stage IIIA breast cancer from centers in the USA, Canada, Poland, Hungary, South Korea and India were treated on Day 1 of each of four 21-day cycles with adjuvant or neo-adjuvant TC. On Day 2 of each cycle, patients received a single subcutaneous dose of either eflapegrastim 13.2 mg/0.6 mL (equivalent to 3.6 mg G-CSF) or pegfilgrastim (6 mg) in a 1:1 ratio. Patients had CBCs drawn on Day 1 prior to chemotherapy and Days 4-15 daily or until recovery of neutropenia in Cycle 1. CBC was also collected on Days 1, 4, 7, 10 and 15 in Cycles 2-4. The primary endpoint was to demonstrate the non-inferiority of eflapegrastim comparing to pegfilgrastim as measured by the mean DSN in Cycle 1 with NI margin of <0.62 day.

Results:

In a total of 237 intent-to-treat patients (randomized to 118 eflapegrastim; 119 pegfilgrastim), median age was 59 years (range 29 to 88 years); mean (SD) DSN was 0.31 (0.688) days for eflapegrastim and 0.39 (0.949) days for pegfilgrastim, demonstrating the non-inferiority (95% CI of ΔDSN: [-0.292, 0.129]; p<0.0001). Non-inferiority of eflapegrastim for DSN was maintained across all 4 cycles. There were no statistically significant differences in secondary endpoints: time to ANC recovery, depth of ANC nadir and incidence of FN at Cycle 1. The common Grade 3/4 adverse events observed in≥5%of patients were similar across both arms and were mainly hematologic including neutropenia, lymphopenia, anemia and leukopenia. Grade 3/4 bone pain and febrile neutropenia rates were similar across both arms and were less than 5%.

Conclusions:

Eflapegrastim, a novel long acting G-CSF demonstrated non-inferiority to pegfilgrastim in the reduction of DSN in breast cancer patients treated with TC and has validated the results from the first Phase 3 ADVANCE study. Eflapegrastim was safe and well-tolerated with a similar safety profile to pegfilgrastim.

Citation Format: Schwartzberg L, Bhat G, Mezei K, Lang I, Moon YW, Senviratne L, Chawla S, Cobb P, Yang Z. Efficacy and safety of eflapegrastim confirmed in reducing severe neutropenia in breast cancer patients treated with myelosuppressive chemotherapy in the second Phase 3 randomized controlled multinational trial compared to pegfilgrastim (RECOVER trial) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-13-05.

Fleck-like deposits and swept source optical coherence tomography characteristics in a case of confirmed ocular chalcosis

A 36-year-old male presented with history of injury in the left eye 3 years back with a copper wire. Examination revealed the presence of typical sunflower cataract with golden yellow deposits over the anterior lens capsule with dull glow and old vitreous hemorrhage. Non-contrast computerized tomography revealed retained intraocular foreign body in the pars plana region. The patient underwent phacoemulsification with intraocular lens implantation followed by pars plana vitrectomy and foreign body removal. Intraoperatively, fleck-like deposits were noted on the retinal surface in a circinate manner around the fovea and also over mid-peripheral retina. Postoperative swept source optical coherence tomography (SS-OCT) was performed to document the location of deposits and their characteristics. Limited literature exists regarding SS-OCT characteristics of ocular chalcosis.

Interplay between hereditary and environmental factors to establish an in vitro disease model of keratoconus

Keratoconus (KC) is a bilateral corneal dystrophy and a multifactorial, multigenic disorder with an etiology involving a strong environmental component and complex inheritance patterns. The underlying pathophysiology of KC is poorly understood because of potential crosstalk between genetic-epigenetic variants possibly triggered by the environmental factors. Here, we decode the etiopathological basis of KC using genomic, transcriptomic, proteomic and metabolic approaches. The lack of relevant models that accurately imitate this condition has been particularly limiting in terms of the effective management of KC. Tissue-engineered in vitro models of KC could address this need and generate valuable insights into its etiopathology for the establishment of disease models to accelerate drug discovery.

Silk-Based Bioinks for 3D Bioprinting

3D bioprinting field is making remarkable progress; however, the development of critical sized engineered tissue construct is still a farfetched goal. Silk fibroin offers a promising choice for bioink material. Nature has imparted several unique structural features in silk protein to ensure spinnability by silkworms or spider. Researchers have modified the structure-property relationship by reverse engineering to further improve shear thinning behavior, high printability, cytocompatible gelation, and high structural fidelity. In this review, it is attempted to summarize the recent advancements made in the field of 3D bioprinting in context of two major sources of silk fibroin: silkworm silk and spider silk (native and recombinant). The challenges faced by current approaches in processing silk bioinks, cellular signaling pathways modulated by silk chemistry and secondary conformations, gaps in knowledge, and future directions acquired for pushing the field further toward clinic are further elaborated.

Regulation of fibrotic changes by the synergistic effects of cytokines, dimensionality and matrix: Towards the development of an in vitro human dermal hypertrophic scar model

Current therapeutic strategies to reduce scarring in full thickness skin defect offer limited success due to poor understanding of scar tissue formation and the underlying signaling pathways. There is an urgent need to develop human cell based in vitro scar tissue models as animal testing is associated with ethical and logistic complications and inter-species variations. Pro-inflammatory cytokines play critical role in regulating scar development through complex interplay and interaction with the ECM and corresponding signaling pathways. In this context, we assessed the responses of cultured fibroblasts with respect to their differentiation into myofibroblasts using optimised cytokines (TGF-β1, IL-6 and IL-8) for scar formation in 2D (tissue culture plate, collagen type I coated plate) vs 3D collagen type I gel based constructs. We attempted to deduce the role of dimensionality of cell culture matrix in modulating differentiation, function and phenotype of cultured fibroblasts. Validation of the developed model showed similarity to etiology and pathophysiology of in vivo hypertrophic scar with respect to several features: 1) transition of fibroblasts to myofibroblasts with convincing expression of α-SMA stress fibers; 2) contraction; 3) excessive collagen and fibronectin secretion; 4) expression of fibrotic ECM proteins (SPARC and Tenascin); 5) low MMP secretion. Most importantly, we elucidated the involvement of TGF-β/SMAD and Wnt/β-catenin pathways in developing in vitro dermal scar. Hence, this relatively simple in vitro human scar tissue equivalent may serve as an alternative for testing and designing of novel therapeutics and help in extending our understanding of the complex interplay of cytokines and related dermal scar specific signaling.

STATEMENT OF SIGNIFICANCE

Scarring of the skin affects almost millions of people per year in the developed world alone, nevertheless the complex pathophysiology and the precise signaling mechanisms responsible for this phenomenon of skin scarring are still unknown. A number of anti-scar drugs are being developed and being tested on animals and monolayer models. However, testing the efficacy of these drugs on lab based 3D in vitro models may prove extremely useful in recapitulating the 3D microenvironment of the native scar tissue. In that context in this study we have demonstrated the development of 3D in vitro dermal scar model, by optimizing a constellation of factors, such as combination of cytokines (TGF-β1,IL-6,IL-8) and cellular dimensionality in inducing the differentiation of dermal fibroblasts to myofibroblasts. This in vitro scar model was successful in replicating hallmark features of hypertrophic scar such as excessive synthesis of fibrotic extracellular matrix, perturbed matrix homeostasis, contraction, diminished MMP synthesis. The study also highlighted significant involvement of TGF-β/SMAD and Wnt/β-catenin signaling pathways in in vitro scar formation.

Morphometry of the lower thoracic and lumbar pedicles and its relevance in pedicle fixation

PURPOSE

To assess the pedicle morphology in the lower thoracic and lumbar spine in an Indian population and to determine the causes of pedicle wall violation by pedicle screws.

METHODS

Computerised tomographic scans of 135 consecutive patients with thoracolumbar and lumbar spine fractures were prospectively analysed to determine the pedicle morphology. The transverse pedicle angle, pedicle diameter and screw path length at 527 uninjured levels were measured. Post-operative CT scans of 117 patients were analysed to determine the accuracy of 468 pedicle screws at 234 vertebrae.

RESULTS

The lowest (mean ± SD) transverse pedicle width in the lower thoracic spine was 5.4 ± 0.70 mm, whereas in the lumbar spine it was 7.2 ± 0.87 mm. The shortest (mean ± SD) screw path length in lower thoracic pedicles was 35.8 ± 2.10 and 41.9 ± 2.18 mm in the lumbar spine. The mean transverse pedicle angle in the lower thoracic spine was consistently less than 5°, whereas it gradually increased from L1 through L5 from 8.5° to 30°. Forty-one screws violated the pedicle wall, due to erroneous angle of screw insertion.

CONCLUSIONS

In the current study, pedicle dimensions were smaller compared to the Western population. In Indian patients, pedicle screws of 5 mm diameter and 30 mm length, and 6 mm diameter and 35 mm length can safely be used in the lower thoracic and lumbar spine, respectively. However, it is important to assess the pedicle morphology on imaging prior to pedicle fixation.

Dynamic Contrast-Enhanced MRI-Derived Intracellular Water Lifetime (τ i ): A Prognostic Marker for Patients with Head and Neck Squamous Cell Carcinomas

BACKGROUND AND PURPOSE

Shutter-speed model analysis of dynamic contrast-enhanced MR imaging allows estimation of mean intracellular water molecule lifetime (a measure of cellular energy metabolism) and volume transfer constant (a measure of hemodynamics). The purpose of this study was to investigate the prognostic utility of pretreatment mean intracellular water molecule lifetime and volume transfer constant in predicting overall survival in patients with squamous cell carcinomas of the head and neck and to stratify p16-positive patients based upon survival outcome.

MATERIALS AND METHODS

A cohort of 60 patients underwent dynamic contrast-enhanced MR imaging before treatment. Median, mean intracellular water molecule lifetime and volume transfer constant values from metastatic nodes were computed from each patient. Kaplan-Meier analyses were performed to associate mean intracellular water molecule lifetime and volume transfer constant and their combination with overall survival for the first 2 years, 5 years, and beyond (median duration, >7 years).

RESULTS

By the last date of observation, 18 patients had died, and median follow-up for surviving patients (n = 42) was 8.32 years. Patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .01) prolonged overall survival by 5 years compared with those with low mean intracellular water molecule lifetime (13 deaths). Similarly, patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .006) longer overall survival at long-term duration than those with low mean intracellular water molecule lifetime (14 deaths). However, volume transfer constant was a significant predictor for only the 5-year follow-up period. There was some evidence (P < .10) to suggest that mean intracellular water molecule lifetime and volume transfer constant were associated with overall survival for the first 2 years. Patients with high mean intracellular water molecule lifetime and high volume transfer constant were associated with significantly (P < .01) longer overall survival compared with other groups for all follow-up periods. In addition, p16-positive patients with high mean intracellular water molecule lifetime and high volume transfer constant demonstrated a trend toward the longest overall survival.

CONCLUSIONS

A combined analysis of mean intracellular water molecule lifetime and volume transfer constant provided the best model to predict overall survival in patients with squamous cell carcinomas of the head and neck.

Why are HIV-infected people not started on antiretroviral therapy? A mixed-methods study from Gujarat, India

Setting: Five purposively selected antiretroviral therapy (ART) centres in Gujarat, India. Objectives: To assess the proportion of ART-eligible people living with the human immunodeficiency virus (PLHIV) who were not initiated on ART within 2 months of being recorded as eligible, to identify factors associated with non-initiation and to explore reasons from the provider's perspective. Design: We used a mixed-methods design (triangulation) of 1) a quantitative phase involving record reviews and cohort analysis (Poisson regression) of PLHIV registered during April 2014-March 2015, and 2) a qualitative phase involving one-to-one interviews with 25 providers. Results: Of 2079 ART-eligible PLHIV, 339 (16%) were not started on ART within 2 months. PLHIV with CD4 counts of <350 cells/μl and patients who were labourers, hospitalised, bedridden or registered with certain ART centres were more likely not to be initiated on ART. Qualitative results were categorised into two broad themes: government health system- and patient-related challenges, which validated and complemented the quantitative findings. Conclusion: Several patient subgroups at greater risk of ART non-initiation were identified, along with reasons for risk; this has important programme implications for achieving the UNAIDS 90-90-90 goal, and particularly the second 90 component of having 90% of diagnosed PLHIV start ART.

A targeted noise reduction observational study for reducing noise in a neonatal intensive unit

BACKGROUND

Excessive noise in neonatal intensive care units (NICUs) can interfere with infants' growth, development and healing.Local problem:Sound levels in our NICUs exceeded the recommended levels by the World Health Organization.

METHODS

We implemented a noise reduction strategy in an urban, tertiary academic medical center NICU that included baseline noise measurements. We conducted a survey involving staff and visitors regarding their opinions and perceptions of noise levels in the NICU. Ongoing feedback to staff after each measurement cycle was provided to improve awareness, engagement and adherence with noise reduction strategies. After widespread discussion with active clinician involvement, consensus building and iterative testing, changes were implemented including: lowering of equipment alarm sounds, designated 'quiet times' and implementing a customized education program for staff.

INTERVENTIONS

A multiphase noise reduction quality improvement (QI) intervention to reduce ambient sound levels in a patient care room in our NICUs by 3 dB (20%) over 18 months.

RESULTS

The noise in the NICU was reduced by 3 dB from baseline. Mean (s.d.) baseline, phase 2, 3 and 4 noise levels in the two NICUs were: LAeq: 57.0 (0.84), 56.8 (1.6), 55.3 (1.9) and 54.5 (2.6) dB, respectively (P<0.01). Adherence with the planned process measure of 'quiet times' was >90%.

CONCLUSIONS

Implementing a multipronged QI initiative resulted in significant noise level reduction in two multipod NICUs. It is feasible to reduce noise levels if QI interventions are coupled with active engagement of the clinical staff and following continuous process of improvement methods, measurements and protocols.

Establishment of in vitro model of corneal scar pathophysiology

Corneal scarring is the major source of permanent blindness worldwide. The complex pathophysiology of corneal scarring is not comprehensibly understood as it involves the interaction of a constellation of pro-fibrotic cytokines influencing several signaling pathways involved in corneal scar development. In the present study, an attempt has been made to generate a relatively simple in vitro corneal scar model using primary corneal keratocytes by exogenously providing an optimized dose of combination of cytokines (TGF-β1, IL-6, and IL-8) involved in scar formation in situ. Data obtained from gene and protein expression analysis depicted enhanced ECM production with discrete expression of myofibroblast specific markers. The protein-protein interactions associated these proteins to various pathways involved in wound healing, cellular migration, and cytoskeletal remodeling justifying high relevance to in vivo scar formation. Hence the developed model can be used to acquire understanding about corneal scar pathophysiology and thus might be useful for designing the treatment modalities and efficacies for controlling scar formation.

Are partners of HIV-infected people being tested for HIV? A mixed-methods research from Gujarat, India

Setting: Four selected antiretroviral therapy (ART) centres of Gujarat State, India, which accounts for 8% of the human immunodeficiency virus (HIV) burden in India. Objectives: 1) To assess the proportion of people living with HIV (PLHIV) whose partners were not tested for HIV; 2) to assess sociodemographic and clinical characteristics of index cases associated with partner testing; and 3) to understand perceived facilitators and barriers to partner testing and make suggestions on how to improve testing from the perspective of the health-care provider. Design: A mixed-method design with a quantitative phase that involved reviewing the programme records of married PLHIV enrolled during 2011-2015, followed by a qualitative phase of key informant interviews. Results: Of 3884 married PLHIV, 1279 (33%) did not have their partners tested for HIV. Factors including index cases being male, illiterate, aged >25 years, belonging to key populations, substance use and being in advanced clinical stages were more likely to be associated with partner non-testing. Non-disclosure of HIV status (due to fear of marital discord) and lack of awareness and risk perception were the key barriers to testing. Conclusion: One third of PLHIV did not have their partners tested for HIV. Several factors were identified as being associated with the non-testing of partners, and solutions were explored that need to be implemented urgently if we are to achieve the 90-90-90 targets and end HIV.

Cord blood lead level in an urban inner-city hospital

Lead levels were measured by inductively coupled plasma mass spectrometry (ICP-MS) in umbilical cord blood samples of 150 neonates in an urban inner-city hospital. The mean (SD) gestation and birth weight of our cohort were 38.8 (1.7) weeks and 3,217 (519) grams. There were 89% African-Americans, 53% males and 79% were born via vaginal delivery. Mean (SD) maternal age was 24.5 (5.8) years. History of drug abuse and smoking was reported in 8.7% and 10.7% respectively, with only 1 mother reporting a history of high lead level in childhood. Prenatal vitamin intake was reported in 99.3%. Cord blood lead level was available in 144 patients, with lead level of <1μg/dL seen in 141 (97.9%) and>1 in 3 (2.1%) patients. No patient had cord blood lead level of >2μg/dL. High lead levels during childhood in high-risk urban population, however, suggest the need for intensive efforts for prevention of environmental exposure to lead in early childhood.

Outcome of uterine sarcoma patients treated with pazopanib: A retrospective analysis based on two European Organisation for Research and Treatment of Cancer (EORTC) Soft Tissue and Bone Sarcoma Group (STBSG) clinical trials 62043 and 62072

BACKGROUND

Uterine sarcomas are a group of mesenchymal tumours comprising several histologies. They have a high recurrence rate following surgery, modest outcome to systemic therapy, and poor overall survival. Pazopanib is a multi-targeted tyrosine kinase inhibitor approved for non-adipocytic advanced soft tissue sarcomas (STS). Here we investigated whether response to pazopanib in patients with uterine sarcomas differs from that of patients with non-uterine sarcomas.

PATIENTS AND METHODS

Uterine sarcoma patients were retrieved from all soft tissue sarcoma patients treated with pazopanib in EORTC Phase II (n=10) and Phase III (PALETTE) (n=34) studies. Patient and tumour characteristics, response, progression free and overall survival data were compared.

RESULTS

Forty-four patients with uterine sarcoma were treated with pazopanib. The majority of patients had uterine leiomyosarcoma (LMS) (n=39, 88.6%) with high grade tumours (n=37, 84.1%) compared to 54.8% (n=164) in the non-uterine population. The median age was 55years (range 33-79) and median follow up was 2.3years. Uterine patients were heavily pre-treated, 61.3% having ≥2 lines of chemotherapy prior to pazopanib compared to 40.8% in the non-uterine population. Five patients (11%), all LMS, had a partial response (95% CI 3.8-24.6). Median progression free survival (PFS) 3.0months (95% CI 2.5-4.7) in uterine versus 4.5 (95% CI 3.7-5.1) in non-uterine STS. Median overall survival (OS) was 17.5months (95% CI 11.1-19.6), longer than the non-uterine population, 11.1months (95% CI 10.2-12.0) (p=0.352).

CONCLUSIONS

Despite heavy pre-treatment, pazopanib shows signs of activity in patients with uterine sarcoma with the similar outcomes to patients with non-uterine STS.

Role of chondroitin sulphate tethered silk scaffold in cartilaginous disc tissue regeneration

Strategies for tissue engineering focus on scaffolds with tunable structure and morphology as well as optimum surface chemistry to simulate the anatomy and functionality of the target tissue. Silk fibroin has demonstrated its potential in supporting cartilaginous tissue formation both in vitro and in vivo. In this study, we investigate the role of controlled lamellar organization and chemical composition of biofunctionalized silk scaffolds in replicating the structural properties of the annulus region of an intervertebral disc using articular chondrocytes. Covalent attachment of chondroitin sulfate (CS) to silk is characterized. CS-conjugated silk constructs demonstrate enhanced cellular metabolic activity and chondrogenic redifferentiation potential with significantly improved mechanical properties over silk-only constructs. A matrix-assisted laser desorption ionization-time of flight analysis and protein-protein interaction studies help to generate insights into how CS conjugation can facilitate the production of disc associated matrix proteins, compared to a silk-only based construct. An in-depth understanding of the interplay between such extra cellular matrix associated proteins should help in designing more rational scaffolds for cartilaginous disc regeneration needs.

Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI

BACKGROUND AND PURPOSE

Characterization of iron deposition associated with demyelinating lesions of multiple sclerosis and neuromyelitis optica has not been well studied. Our aim was to investigate the potential of ultra-high-field MR imaging to distinguish MS from neuromyelitis optica and to characterize tissue injury associated with iron pathology within lesions.

MATERIALS AND METHODS

Twenty-one patients with MS and 21 patients with neuromyelitis optica underwent 7T high-resolution 2D-gradient-echo-T2* and 3D-susceptibility-weighted imaging. An in-house-developed algorithm was used to reconstruct quantitative susceptibility mapping from SWI. Lesions were classified as "iron-laden" if they demonstrated hypointensity on gradient-echo-T2*-weighted images and/or SWI and hyperintensity on quantitative susceptibility mapping. Lesions were considered "non-iron-laden" if they were hyperintense on gradient-echo-T2* and isointense or hyperintense on quantitative susceptibility mapping.

RESULTS

Of 21 patients with MS, 19 (90.5%) demonstrated at least 1 quantitative susceptibility mapping-hyperintense lesion, and 11/21 (52.4%) had iron-laden lesions. No quantitative susceptibility mapping-hyperintense or iron-laden lesions were observed in any patients with neuromyelitis optica. Iron-laden and non-iron-laden lesions could each be further characterized into 2 distinct patterns based on lesion signal and morphology on gradient-echo-T2*/SWI and quantitative susceptibility mapping. In MS, most lesions (n = 262, 75.9% of all lesions) were hyperintense on gradient-echo T2* and isointense on quantitative susceptibility mapping (pattern A), while a small minority (n = 26, 7.5% of all lesions) were hyperintense on both gradient-echo-T2* and quantitative susceptibility mapping (pattern B). Iron-laden lesions (n = 57, 16.5% of all lesions) were further classified as nodular (n = 22, 6.4%, pattern C) or ringlike (n = 35, 10.1%, pattern D).

CONCLUSIONS

Ultra-high-field MR imaging may be useful in distinguishing MS from neuromyelitis optica. Different patterns related to iron and noniron pathology may provide in vivo insight into the pathophysiology of lesions in MS.

High-contrast laser acceleration of relativistic electrons in solid cone-wire targets

The consequences of small scale-length precursor plasmas on high-intensity laser-driven relativistic electrons are studied via experiments and simulations. Longer scale-length plasmas are shown to dramatically increase the efficiency of electron acceleration, yet, if too long, they reduce the coupling of these electrons into the solid target. Evidence for the existence of an optimal plasma scale-length is presented and estimated to be from 1 to 5μm. Experiments on the Trident laser (I=5×10(19)W/cm(2)) diagnosed via Kα emission from Cu wires attached to Au cones are quantitively reproduced using 2D particle-in-cell simulations that capture the full temporal and spatial scale of the nonlinear laser interaction and electron transport. The simulations indicate that 32%±8%(6.5%±2%) of the laser energy is coupled into electrons of all energies (1-3 MeV) reaching the inner cone tip and that, with an optimized scale-length, this could increase to 35% (9%).

Whole-Brain N-Acetylaspartate Concentration Is Preserved during Mild Hypercapnia Challenge

BACKGROUND AND PURPOSE

Although NAA is often used as a marker of neuronal health and integrity in neurologic disorders, its normal response to physiologic challenge is not well-established and its changes are almost always attributed exclusively to brain pathology. The purpose of this study was to test the hypothesis that the neuronal cell marker NAA, often used to assess neuronal health and integrity in neurologic disorders, is not confounded by (possibly transient) physiologic changes. Therefore, its decline, when observed by using (1)H-MR spectroscopy, can almost always be attributed exclusively to brain pathology.

MATERIALS AND METHODS

Twelve healthy young male adults underwent a transient hypercapnia challenge (breathing 5% CO2 air mixture), a potent vasodilator known to cause a substantial increase in CBF and venous oxygenation. We evaluated their whole-brain NAA by using nonlocalizing proton MR spectroscopy, venous oxygenation with T2-relaxation under spin-tagging MR imaging, CBF with pseudocontinuous arterial spin-labeling, and the cerebral metabolic rate of oxygen, during normocapnia (breathing room air) and hypercapnia.

RESULTS

There was insignificant whole-brain NAA change (P = .88) from normocapnia to hypercapnia and back to normocapnia in this cohort, as opposed to highly significant increases: 28.0 ± 10.3% in venous oxygenation and 49.7 ± 16.6% in global CBF (P < 10(-4)); and a 6.4 ± 10.9% decrease in the global cerebral metabolic rate of oxygen (P = .04).

CONCLUSIONS

Stable whole-brain NAA during normocapnia and hypercapnia, despite significant global CBF and cerebral metabolic rate of oxygen changes, supports the hypothesis that global NAA changes are insensitive to transient physiology. Therefore, when observed, they most likely reflect underlying pathology resulting from neuronal cell integrity/viability changes, instead of a response to physiologic changes.

Differentiating Tumor Progression from Pseudoprogression in Patients with Glioblastomas Using Diffusion Tensor Imaging and Dynamic Susceptibility Contrast MRI

BACKGROUND AND PURPOSE

Early assessment of treatment response is critical in patients with glioblastomas. A combination of DTI and DSC perfusion imaging parameters was evaluated to distinguish glioblastomas with true progression from mixed response and pseudoprogression.

MATERIALS AND METHODS

Forty-one patients with glioblastomas exhibiting enhancing lesions within 6 months after completion of chemoradiation therapy were retrospectively studied. All patients underwent surgery after MR imaging and were histologically classified as having true progression (>75% tumor), mixed response (25%-75% tumor), or pseudoprogression (<25% tumor). Mean diffusivity, fractional anisotropy, linear anisotropy coefficient, planar anisotropy coefficient, spheric anisotropy coefficient, and maximum relative cerebral blood volume values were measured from the enhancing tissue. A multivariate logistic regression analysis was used to determine the best model for classification of true progression from mixed response or pseudoprogression.

RESULTS

Significantly elevated maximum relative cerebral blood volume, fractional anisotropy, linear anisotropy coefficient, and planar anisotropy coefficient and decreased spheric anisotropy coefficient were observed in true progression compared with pseudoprogression (P < .05). There were also significant differences in maximum relative cerebral blood volume, fractional anisotropy, planar anisotropy coefficient, and spheric anisotropy coefficient measurements between mixed response and true progression groups. The best model to distinguish true progression from non-true progression (pseudoprogression and mixed) consisted of fractional anisotropy, linear anisotropy coefficient, and maximum relative cerebral blood volume, resulting in an area under the curve of 0.905. This model also differentiated true progression from mixed response with an area under the curve of 0.901. A combination of fractional anisotropy and maximum relative cerebral blood volume differentiated pseudoprogression from nonpseudoprogression (true progression and mixed) with an area under the curve of 0.807.

CONCLUSIONS

DTI and DSC perfusion imaging can improve accuracy in assessing treatment response and may aid in individualized treatment of patients with glioblastomas.