COVID-19 rebound after Paxlovid treatment during Omicron BA.5 vs BA.2.12.1 subvariant predominance period

Paxlovid was authorized by FDA to treat mild-to-moderate COVID-19. In May 2022, the Centers for Disease Control and Prevention (CDC) issued a Health Alert Network Health Advisory on potential COVID-19 rebound after Paxlovid treatment. Since June 2022, Omicron BA.5 has become the dominant subvariant in the US, which is more resistant to neutralizing antibodies than the previous subvariant BA.2.12.1. Questions remain as to how COVID-19 rebound after Paxlovid treatment differs between the BA.5 and BA.2.12.1 subvariants. This is a retrospective cohort study of 15,913 patients who contracted COVID-19 between 5/8/2022-7/18/2022 and were prescribed Paxlovid within 5 days of their COVID-19 infection. The study population was divided into 2 cohorts: (1) BA.5 cohort (n=5,161) - contracted COVID-19 during 6/19/22-7/18/22 when BA.5 was the predominant subvariant2. (2) BA.2.12.1 cohort (n=10,752) - contracted COVID-19 during 5/8/22-6/18/22 when the BA.2.12.1 was the predominant subvariant. The risks of both COVID-19 rebound infections and symptoms 2-8 days after Paxlovid treatment were higher in the BA.5 cohort than in the propensity-score matched BA.2.12.1 cohort: rebound infections (Hazard Ratio or HR: 1.32, 95% CI: 1.06-1.66), rebound symptoms (HR: 1.32, 95% CI: 1.04-1.68). As SARS-CoV-2 evolves with successive subvariants more evasive to antibodies, continuous vigilant monitoring is necessary for COVID-19 rebounds after Paxlovid treatment and longer time duration of Paxlovid treatment warrants evaluation.

Incidence Rates and Clinical Outcomes of SARS-CoV-2 Infection With the Omicron and Delta Variants in Children Younger Than 5 Years in the US

This cohort study assesses the incidence rates and clinical outcomes of SARS-CoV-2 infection with the Omicron and Delta variants in children younger than 5 years in the US.

COVID-19 rebound after Paxlovid and Molnupiravir during January-June 2022

Importance

Recent case reports document that some patients who were treated with Paxlovid experienced rebound COVID-19 infections and symptoms 2 to 8 days after completing a 5-day course of Paxlovid. The Centers for Disease Control and Prevention (CDC) has recently issued a Health Alert Network Health Advisory to update the public on the potential for COVID-19 rebound after Paxlovid treatments. However, the rates of COVID-19 rebound in a real-world population or whether rebound is unique to Paxlovid remains unknown.

Objectives

To examine the rates and relative risks of COVID-19 rebound in patients treated with Paxlovid or with Molnupiravir and to compare characteristics of patients who experienced COVID-19 rebound to those who did not.

Design Setting and Participants

Retrospective cohort study of electronic health records (EHRs) of 92 million patients from a multicenter and nationwide database in the US. The study population comprised 13,644 patients age ≥ 18 years who contracted COVID-19 between 1/1/2022-6/8/2022 and were treated with Paxlovid (n =11,270) or with Molnupiravir (n =2,374) within 5 days of their COVID-19 infection.

Exposures

Paxlovid or Molnupiravir.

Main Outcomes and Measures

Three types of COVID-19 rebound outcomes (COVID-19 infections, COVID-19 related symptoms, and hospitalizations) were examined. Hazard ratios and 95% confidence interval (CI) of 7-day and 30-day risk for COVID-19 rebound between patients treated with Paxlovid and patients treated with Molnupiravir were calculated before and after propensity-score matching.

Results

The 7-day and 30-day COVID-19 rebound rates after Paxlovid treatment were 3.53% and 5.40% for COVID-19 infection, 2.31% and 5.87% for COVID-19 symptoms, and 0.44% and 0.77% for hospitalizations. The 7-day and 30-day COVID-19 rebound rates after Molnupiravir treatment were 5.86% and 8.59% for COVID-19 infection, 3.75% and 8.21% for COVID-19 symptoms, and 0.84% and 1.39% for hospitalizations. After propensity-score matching, there were no significant differences in COVID-19 rebound risks between Paxlovid and Molnupiravir: infection (HR 0.90, 95% CI: 0.73-1.11), COVID-19 symptoms (HR: 1.03, 95% CI: 0.83-1.27), or hospitalizations (HR: 0.92, 95% CI: 0.56-1.55). Patients with COVID-19 rebound had significantly higher prevalence of underlying medical conditions than those without.

Conclusions and Relevance

COVID-19 rebound occurred both after Paxlovid and Molnupiravir, especially in patients with underlying medical conditions. This indicates that COVID-19 rebound is not unique to Paxlovid and the risks were similar for Paxlovid and Molnupiravir. For both drugs the rates of COVID-19 rebound increased with time after treatments. Our results call for continuous surveillance of COVID-19 rebound after Paxlovid and Molnupiravir treatments. Studies are necessary to determine the mechanisms underlying COVID-19 rebounds and to test dosing and duration regimes that might prevent such rebounds in vulnerable patients.

Potential long-term effect of tumor necrosis factor inhibitors on dementia risk: A propensity score matched retrospective cohort study in US veterans

INTRODUCTION

Tumor necrosis factor (TNF) inhibitors are widely used to treat rheumatoid arthritis (RA) and their potential to retard Alzheimer's disease (AD) progression has been reported. However, their long-term effects on the dementia/AD risk remain unknown.

METHODS

A propensity scored matched retrospective cohort study was conducted among 40,207 patients with RA within the US Veterans Affairs health-care system from 2000 to 2020.

RESULTS

A total of 2510 patients with RA prescribed TNF inhibitors were 1:2 matched to control patients. TNF inhibitor use was associated with reduced dementia risk (hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.52-0.80), which was consistent as the study period increased from 5 to 20 years after RA diagnosis. TNF inhibitor use also showed a long-term effect in reducing the risk of AD (HR: 0.57, 95% CI: 0.39-0.83) during the 20 years of follow-up.

CONCLUSION

TNF inhibitor use is associated with lower long-term risk of dementia/AD among US veterans with RA.

COVID infection rates, clinical outcomes, and racial/ethnic and gender disparities before and after Omicron emerged in the US

Background

SARS-CoV-2 infections and hospitalizations are rising in the US and other countries after the emergence of the Omicron variant. Currently, data on infection rates, severity and racial/ethnic and gender disparities from Omicron in the US is limited.

Method

We performed a retrospective cohort study of a large, geographically diverse database of patient electronic health records (EHRs) in the US. The study population comprised 881,473 patients who contracted SARS-CoV-2 infection for the first time between 9/1/2021-1/16/2022, including 147,964 patients infected when Omicron predominated (Omicron cohort), 633,581 when Delta predominated (Delta cohort) and another 99,928 infected when the Delta predominated but just before the Omicron variant was detected in the US (Delta-2 cohort). We examined monthly incidence rates of COVID-19 infections stratified by age groups, gender, race and ethnicity, compared severe clinical outcomes including emergency department (ED) visits, hospitalizations, intensive care unit (ICU) admissions, and mechanical ventilation use between propensity-score matched Omicron and Delta cohorts stratified by age groups (0-4, 5-17, 18-64 and ≥ 65 years), and examined racial/ethnic and gender differences in severe clinical outcomes.

Findings

Among 147,964 infected patients in the Omicron cohort (average age: 39.1 years), 56.7% were female, 2.4% Asian, 21.1% Black, 6.2% Hispanic, and 51.8% White. The monthly incidence rate of COVID infections (new cases per 1000 persons per day) was 0.5-0.7 when Delta predominated, and rapidly increased to 3.8-5.2 when Omicron predominated. In January 2022, the infection rate was highest in children under 5 years (11.0) among all age groups, higher in Black than in White patients (14.0 vs. 3.8), and higher in Hispanic than in non-Hispanic patients (8.9 vs. 3.1). After propensity-score matching for demographics, socio-economic determinants of health, comorbidities and medications, risks for severe clinical outcomes in the Omicron cohort were significantly lower than in the Delta cohort: ED visits: 10.2% vs. 14.6% (risk ratio or RR: 0.70 [0.68-0.71]); hospitalizations: 2.6% vs. 4.4% (RR: 0.58 [0.55-0.60]); ICU admissions: 0.47% vs. 1.00% (RR: 0.47 [0.43-0.51]); mechanical ventilation: 0.08% vs. 0.3% (RR: 0.25 [0.20-0.31]). Similar reduction in disease severity was observed for all age groups. There were significant racial/ethnic and gender disparities in severe clinical outcomes in the Omicron cohort, with Black, Hispanic patients having more ED visits and ICU admissions than White and non-Hispanic patients, respectively and women had fewer hospitalization and ICU admission than men.

Interpretation

The incidence rate of COVID infection during the omicron predominant period (prevalence >92%) was 6-8 times higher than during the Delta predominant period that preceded it consistent with greater infectivity. The incidence rate was highest among those less than 5 years of age, and in Black and Hispanic patients. COVID infections occurring when the Omicron predominated were associated with significantly less frequent severe outcomes than in matched patients when the Delta variant predominated. There were significant racial, ethnic and gender disparities in severe clinical outcomes, with Black and Hispanic patients and men disproportionally impacted.

Comparison of mRNA-1273 and BNT162b2 Vaccines on Breakthrough SARS-CoV-2 Infections, Hospitalizations, and Death During the Delta-Predominant Period

This study examines breakthrough SARS-CoV-2 infections, hospitalizations, and mortality in March-August 2021, when the Delta variant predominated, among a general US cohort vaccinated with mRNA-1273 or BNT162b2.

Increasing life expectancy in cystic fibrosis: Advances and challenges

Since the first description of cystic fibrosis in 1938, there have been significant advances in both quality of life and longevity for people living with this disease. In this article we describe the milestones of the last 80 years and what we perceive to be the remaining barriers to normalcy for this population.

Increased risk for COVID-19 breakthrough infection in fully vaccinated patients with substance use disorders in the United States between December 2020 and August 2021

Individuals with substance use disorders (SUDs) are at increased risk for COVID-19 infection and for adverse outcomes of the infection. Though vaccines are highly effective against COVID-19, their effectiveness in individuals with SUDs might be curtailed by compromised immune status and a greater likelihood of exposures, added to the waning vaccine immunity and the new SARS-CoV-2 variants. In a population-based cohort study, we assessed the risk, time trends, outcomes and disparities of COVID-19 breakthrough infection in fully vaccinated SUD patients starting 14 days after completion of vaccination. The study included 579,372 individuals (30,183 with a diagnosis of SUD and 549,189 without such a diagnosis) who were fully vaccinated between December 2020 and August 2021, and had not contracted COVID-19 infection prior to vaccination. We used the TriNetX Analytics network platform to access de-identified electronic health records from 63 health care organizations in the US. Among SUD patients, the risk for breakthrough infection ranged from 6.8% for tobacco use disorder to 7.8% for cannabis use disorder, all significantly higher than the 3.6% in non-SUD population (p<0.001). Breakthrough infection risk remained significantly higher after controlling for demographics (age, gender, ethnicity) and vaccine types for all SUD subtypes, except for tobacco use disorder, and was highest for cocaine and cannabis use disorders (hazard ratio, HR=2.06, 95% CI: 1.30-3.25 for cocaine; HR=1.92, 95% CI: 1.39-2.66 for cannabis). When we matched SUD and non-SUD individuals for lifetime comorbidities and adverse socioeconomic determinants of health, the risk for breakthrough infection no longer differed between these populations, except for patients with cannabis use disorder, who remained at increased risk (HR=1.55, 95% CI: 1.22-1.99). The risk for breakthrough infection was higher in SUD patients who received the Pfizer than the Moderna vaccine (HR=1.49, 95% CI: 1.31-1.69). In the vaccinated SUD population, the risk for hospitalization was 22.5% for the breakthrough cohort and 1.6% for the non-breakthrough cohort (risk ratio, RR=14.4, 95% CI: 10.19-20.42), while the risk for death was 1.7% and 0.5% respectively (RR=3.5, 95% CI: 1.74-7.05). No significant age, gender and ethnic disparities for breakthrough infection were observed in vaccinated SUD patients. These data suggest that fully vaccinated SUD individuals are at higher risk for breakthrough COVID-19 infection, and this is largely due to their higher prevalence of comorbidities and adverse socioeconomic determinants of health compared with non-SUD individuals. The high frequency of comorbidities in SUD patients is also likely to contribute to their high rates of hospitalization and death following breakthrough infection.

COVID infection severity in children under 5 years old before and after Omicron emergence in the US

Importance

Pediatric SARS-CoV-2 infections and hospitalizations are rising in the US and other countries after the emergence of Omicron variant. However data on disease severity from Omicron compared with Delta in children under 5 in the US is lacking.

Objectives

To compare severity of clinic outcomes in children under 5 who contracted COVID infection for the first time before and after the emergence of Omicron in the US.

Design Setting and Participants

This is a retrospective cohort study of electronic health record (EHR) data of 79,592 children under 5 who contracted SARS-CoV-2 infection for the first time, including 7,201 infected between 12/26/2021-1/6/2022 when the Omicron predominated (Omicron cohort), 63,203 infected between 9/1/2021-11/15/2021 when the Delta predominated (Delta cohort), and another 9,188 infected between 11/16/2021-11/30/2021 when the Delta predominated but immediately before the Omicron variant was detected in the US (Delta-2 cohort).

Exposures

First time infection of SARS-CoV-2.

Main Outcomes and Measures

After propensity-score matching, severity of COVID infections including emergency department (ED) visits, hospitalizations, intensive care unit (ICU) admissions, and mechanical ventilation use in the 3-day time-window following SARS-CoV-2 infection were compared between Omicron and Delta cohorts, and between Delta-2 and Delta cohorts. Risk ratios, and 95% confidence intervals (CI) were calculated.

Results

Among 7,201 infected children in the Omicron cohort (average age, 1.49 ± 1.42 years), 47.4% were female, 2.4% Asian, 26.1% Black, 13.7% Hispanic, and 44.0% White. Before propensity score matching, the Omicron cohort were younger than the Delta cohort (average age 1.49 vs 1.73 years), comprised of more Black children, and had fewer comorbidities. After propensity-score matching for demographics, socio-economic determinants of health, comorbidities and medications, risks for severe clinical outcomes in the Omicron cohort were significantly lower than those in the Delta cohort: ED visits: 18.83% vs. 26.67% (risk ratio or RR: 0.71 [0.66-0.75]); hospitalizations: 1.04% vs. 3.14% (RR: 0.33 [0.26-0.43]); ICU admissions: 0.14% vs. 0.43% (RR: 0.32 [0.16-0.66]); mechanical ventilation: 0.33% vs. 1.15% (RR: 0.29 [0.18-0.46]). Control studies comparing Delta-2 to Delta cohorts show no difference.

Conclusions and Relevance

For children under age 5, first time SARS-CoV-2 infections occurring when the Omicron predominated (prevalence >92%) was associated with significantly less severe outcomes than first-time infections in similar children when the Delta variant predominated.

Comparison of outcomes from COVID infection in pediatric and adult patients before and after the emergence of Omicron

Background

The Omicron SARS-CoV-2 variant is rapidly spreading in the US since December 2021 and is more contagious than earlier variants. Currently, data on the severity of the disease caused by the Omicron variant compared with the Delta variant is limited. Here we compared 3-day risks of emergency department (ED) visit, hospitalization, intensive care unit (ICU) admission, and mechanical ventilation in patients who were first infected during a time period when the Omicron variant was emerging to those in patients who were first infected when the Delta variant was predominant.

Method

This is a retrospective cohort study of electronic health record (EHR) data of 577,938 first-time SARS-CoV-2 infected patients from a multicenter, nationwide database in the US during 9/1/2021-12/24/2021, including 14,054 who had their first infection during the 12/15/2021-12/24/2021 period when the Omicron variant emerged ("Emergent Omicron cohort") and 563,884 who had their first infection during the 9/1/2021-12/15/2021 period when the Delta variant was predominant ("Delta cohort"). After propensity-score matching the cohorts, the 3-day risks of four outcomes (ED visit, hospitalization, ICU admission, and mechanical ventilation) were compared. Risk ratios, and 95% confidence intervals (CI) were calculated.

Results

Of 14,054 patients in the Emergent Omicron cohort (average age, 36.4 ± 24.3 years), 27.7% were pediatric patients (<18 years old), 55.4% female, 1.8% Asian, 17.1% Black, 4.8% Hispanic, and 57.3% White. The Emergent Omicron cohort differed significantly from the Delta cohort in demographics, comorbidities, and socio-economic determinants of health. After propensity-score matching for demographics, socio-economic determinants of health, comorbidities, medications and vaccination status, the 3-day risks in the Emergent Omicron cohort outcomes were consistently less than half those in the Delta cohort: ED visit: 4.55% vs. 15.22% (risk ratio or RR: 0.30, 95% CI: 0.28-0.33); hospitalization: 1.75% vs. 3.95% (RR: 0.44, 95% CI: 0.38-0.52]); ICU admission: 0.26% vs. 0.78% (RR: 0.33, 95% CI:0.23-0.48); mechanical ventilation: 0.07% vs. 0.43% (RR: 0.16, 95% CI: 0.08-0.32). In children under 5 years old, the overall risks of ED visits and hospitalization in the Emergent Omicron cohort were 3.89% and 0.96% respectively, significantly lower than 21.01% and 2.65% in the matched Delta cohort (RR for ED visit: 0.19, 95% CI: 0.14-0.25; RR for hospitalization: 0.36, 95% CI: 0.19-0.68). Similar trends were observed for other pediatric age groups (5-11, 12-17 years), adults (18-64 years) and older adults (≥ 65 years).

Conclusions

First time SARS-CoV-2 infections occurring at a time when the Omicron variant was rapidly spreading were associated with significantly less severe outcomes than first-time infections when the Delta variant predominated.

Association of COVID-19 with New-Onset Alzheimer's Disease

An infectious etiology of Alzheimer's disease has been postulated for decades. It remains unknown whether SARS-CoV-2 viral infection is associated with increased risk for Alzheimer's disease. In this retrospective cohort study of 6,245,282 older adults (age ≥65 years) who had medical encounters between 2/2020-5/2021, we show that people with COVID-19 were at significantly increased risk for new diagnosis of Alzheimer's disease within 360 days after the initial COVID-19 diagnosis (hazard ratio or HR:1.69, 95% CI: 1.53-1.72), especially in people age ≥85 years and in women. Our findings call for research to understand the underlying mechanisms and for continuous surveillance of long-term impacts of COVID-19 on Alzheimer's disease.

Gut-microbiota-microglia-brain interactions in Alzheimer's disease: knowledge-based, multi-dimensional characterization

BACKGROUND

Interactions between the gut microbiota, microglia, and aging may modulate Alzheimer's disease (AD) pathogenesis but the precise nature of such interactions is not known.

METHODS

We developed an integrated multi-dimensional, knowledge-driven, systems approach to identify interactions among microbial metabolites, microglia, and AD. Publicly available datasets were repurposed to create a multi-dimensional knowledge-driven pipeline consisting of an integrated network of microbial metabolite-gene-pathway-phenotype (MGPPN) consisting of 34,509 nodes (216 microbial metabolites, 22,982 genes, 1329 pathways, 9982 mouse phenotypes) and 1,032,942 edges.

RESULTS

We evaluated the network-based ranking algorithm by showing that abnormal microglia function and physiology are significantly associated with AD pathology at both genetic and phenotypic levels: AD risk genes were ranked at the top 6.4% among 22,982 genes, P < 0.001. AD phenotypes were ranked at the top 11.5% among 9982 phenotypes, P < 0.001. A total of 8094 microglia-microbial metabolite-gene-pathway-phenotype-AD interactions were identified for top-ranked AD-associated microbial metabolites. Short-chain fatty acids (SCFAs) were ranked at the top among prioritized AD-associated microbial metabolites. Through data-driven analyses, we provided evidence that SCFAs are involved in microglia-mediated gut-microbiota-brain interactions in AD at both genetic, functional, and phenotypic levels.

CONCLUSION

Our analysis produces a novel framework to offer insights into the mechanistic links between gut microbial metabolites, microglia, and AD, with the overall goal to facilitate disease mechanism understanding, therapeutic target identification, and designing confirmatory experimental studies.

COVID-19 and dementia: Analyses of risk, disparity, and outcomes from electronic health records in the US

Introduction

At present, there is limited data on the risks, disparity, and outcomes for COVID‐19 in patients with dementia in the United States.

Methods

This is a retrospective case‐control analysis of patient electronic health records (EHRs) of 61.9 million adult and senior patients (age ≥ 18 years) in the United States up to August 21, 2020.

Results

Patients with dementia were at increased risk for COVID‐19 compared to patients without dementia (adjusted odds ratio [AOR]: 2.00 [95% confidence interval (CI), 1.94–2.06], P < .001), with the strongest effect for vascular dementia (AOR: 3.17 [95% CI, 2.97–3.37], P < .001), followed by presenile dementia (AOR: 2.62 [95% CI, 2.28–3.00], P < .001), Alzheimer's disease (AOR: 1.86 [95% CI, 1.77–1.96], P < .001), senile dementia (AOR: 1.99 [95% CI, 1.86–2.13], P < .001) and post‐traumatic dementia (AOR: 1.67 [95% CI, 1.51–1.86] P < .001). Blacks with dementia had higher risk of COVID‐19 than Whites (AOR: 2.86 [95% CI, 2.67–3.06], P < .001). The 6‐month mortality and hospitalization risks in patients with dementia and COVID‐19 were 20.99% and 59.26%, respectively.

Discussion

These findings highlight the need to protect patients with dementia as part of the strategy to control the COVID‐19 pandemic.

COVID-19 risk, disparities and outcomes in patients with chronic liver disease in the United States

BACKGROUND

Scientific evidence is lacking regarding the risk of patients with chronic liver disease (CLD) for COVID-19, and how these risks are affected by age, gender and race.

METHODS

We performed a case-control study of electronic health records of 62.2 million patients (age >18 years) in the US up to October 1st, 2020, including 1,034,270 patients with CLD, 16,530 with COVID-19, and 820 with both COVID-19 and CLD. We assessed the risk, disparities, and outcomes of COVID-19 in patients with six major CLDs.

FINDINGS

Patients with a recent medical encounter for CLD were at significantly increased risk for COVID-19 compared with patients without CLD, with the strongest effect in patients with chronic non-alcoholic liver disease [adjusted odd ratio (AOR)=13.11, 95% CI: 12.49-13.76, p < 0.001] and non-alcoholic cirrhosis (AOR=11.53, 95% CI: 10.69-12.43, p < 0.001), followed by chronic hepatitis C (AOR=8.93, 95% CI:8.25-9.66, p < 0.001), alcoholic liver damage (AOR=7.05, 95% CI:6.30-7.88, p < 0.001), alcoholic liver cirrhosis (AOR=7.00, 95% CI:6.15-7.97, p < 0.001) and chronic hepatitis B (AOR=4.37, 95% CI:3.35-5.69, p < 0.001). African Americans with CLD were twice more likely to develop COVID-19 than Caucasians. Patients with COVID-19 and a recent encounter for CLD had a death rate of 10.3% (vs. 5.5% among COVID-19 patients without CLD, p < 0.001) and a hospitalization rate of 41.0% (vs. 23.9% among COVID-19 patients without CLD, p < 0.001).

INTERPRETATION

Patients with CLD, especially African Americans, were at increased risk for COVID-19, highlighting the need to protect these patients from exposure to virus infection.

FUNDING

National Institutes of Health (AG057557, AG061388, AG062272, 1UL1TR002548-01), American Cancer Society (RSG-16-049-01-MPC).

Research in academic medical centers: Two threats to sustainable support

Reductions in federal support and clinical revenue jeopardize biomedical research and, in turn, clinical medicine.

Non-covalent ligand conjugation to biotinylated DNA nanoparticles using TAT peptide genetically fused to monovalent streptavidin

DNA nanoparticles (DNA NPs), which self-assemble from DNA plasmids and poly-L-lysine (pLL)-polyethylene glycol (PEG) block copolymers, transfect several cell types in vitro and in vivo with minimal toxicity and immune response. To further enhance the gene transfer efficiency of DNA NP and control its tropism, we established a strategy to efficiently attach peptide ligands to DNA NPs. The non-covalent biotin-streptavidin (SA) interaction was used for ligand conjugation to overcome problems associated with covalent conjugation methods. A fusion protein of SA with the HIV-1 TAT peptide was cloned, expressed, purified and attached to biotinylated DNA NPs. A modified SA system with tetrameric structure but monovalent biotin binding capacity was adopted and shown to reduce the aggregation of biotinylated DNA NPs compared to neutravidin. Compared to unmodified DNA NPs, TAT modified DNA NPs significantly enhanced in vitro gene transfer, particularly at low DNA concentrations. Studies of cellular uptake and cellular distribution of the DNA NPs indicated that attaching TAT enhanced binding of DNA NPs to cell surface but not internalization at high DNA concentrations. In vivo studies showed that TAT modified DNA NPs mediated equal level of gene transfer to the mouse airways via the luminal route compared to unmodified DNA NPs.

Genetic variation and clinical heterogeneity in cystic fibrosis

Cystic fibrosis (CF), a lethal genetic disease, is characterized by substantial clinical heterogeneity. Work over the past decade has established that much of the variation is genetically conferred, and recent studies have begun to identify chromosomal locations that identify specific genes as contributing to this variation. Transcriptomic and proteomic data, sampling hundreds and thousands of genes and their products, point to pathways that are altered in the cells and tissues of CF patients. Genetic studies have examined more than half a million polymorphic sites and have identified regions, and probably genes, that contribute to the clinical heterogeneity. The combination of these approaches has great potential because genetic profiling identifies putative disease-modifying processes, and transcript and protein profiling is shedding light on the biology involved. Such studies are providing new insights into the disease, such as altered apoptotic responses, oxidative stress dysregulation, and neuronal involvement, all of which may open new therapeutic avenues to exploration.