Johnson, Ruth

Background Obstructive sleep apnea (OSA) increases the risk for metabolic and cardiovascular disease. Telomere shortening has been linked to hypertension, diabetes mellitus, and cardiovascular diseases such as stroke and myocardial infarction. Because these conditions are highly prevalent in sleep apnea, we hypothesized that telomere length (TL) would be reduced in patients with OSA. Methods Genomic DNA was isolated from circulating leukocytes in 176 subjects (42.8 ± 13.8 years, 22.7 % women) who had undergone overnight polysomnographic evaluation. Of these individuals, 92 subjects had an Apnea Hypopnea Index (AHI) >5 events/hour and were classified as OSA patients. TL was measured using a quantitative PCR where a telomere to single copy gene ratio is determined and represented as number of base pairs (bp). The effect of OSA on TL was determined by comparing a control group (no OSA) (AHI<5, n=92) with patients with mild OSA (≥ 5 AHI <15, n=25), and those with moderate to severe OSA (AHI ≥15, n=59) in unadjusted and age‐adjusted models. Results Compared to control subjects, mild and moderate to severe OSA subjects were older: 48.9 ± 11.2 vs. 36.0 ± 11.2 years (p<0.001) and 50.8 ± 13.1 vs. 36.0 ± 11.2 years (p<0.001), respectively. Statistical models examining the effects of OSA severity on TL showed a J‐shaped curve : longer TL in moderate to severe OSA (4867 ± 221 bp) and controls (4820 ± 160 bp), and the shortest TL in mild OSA (4742 ± 155 bp). The mean TL in moderate to severe OSA was significantly longer than in mild OSA (p=0.0048). These effects were more pronounced after adjustment for age, when we observed significant differences in mean TL between moderate to severe OSA and mild OSA (p=0.0036) and between moderate to severe OSA and the control group (p=0.0379) (). However, the mean TL between control subjects and subjects with mild OSA was not different. Conclusion Moderate to severe OSA patients had longer TL compared with mild OSA and control group. This association was independent of age. Even though OSA is associated with increased cardiovascular risk, telomere lengthening in subjects with moderate to severe OSA suggests the presence of protective compensatory mechanisms to prevent telomere shortening in OSA. On the other hand, the existence of longer telomere in subjects with moderate and severe OSA may also indicate triggering of molecular mechanisms which may contribute to cancer development. Further studies are needed to explain the role of hypoxia in telomere dynamics in OSA, and the interactions between telomere length and increased longevity reported in older patients with OSA. Support or Funding Information NIH R01 grant (#HL65176); Singh P. is supported by AHA scientist development grant (11SDG7260046). Becari C. is supported by grant from CNPq‐Brazil (# 203802/2014‐4).

Abstract Renal artery stenosis is common in the elderly population; biomarkers that predict response to restoration of blood flow have not been previously established. Methods We have previously shown in murine model that cuff removal 7 days (7D Cuff-off) after initial placement on the renal artery results in reversible injury whereas cuff removal 14 days (14D Cuff-off) after placement results in irreversible renal injury, when assessed at 28 days after initial surgery. Positive and negative controls consisted of cuff placement for 28 days (28D) and sham surgeries respectively. We performed RNASeq on whole renal cortex to identify innate immune pathways that correlate with reversible versus irreversible injury. Data were normalized to appropriate sham controls in all the groups. Induction of greater than log2 ratio &gt; 2 and p &lt; 0.00001 were considered significant (following adjustment for multiple comparisons). Results As assessed by RNASeq, progression of renal disease (14D Cuff-off & 28D mice) was associated with persistent upregulation of genes associated with T cell signaling and macrophage polarization compared to reversible injury (7D Cuff off). Upregulated genes included but not limited to: CCL5, CCR5, CCL2, CXCL1, CXCL9, CXCL10, CXCR3, TLR2, KLF6, CD74, CD4, CD14, CD44, CD83, CD84, IL1R1, IL1B, SPP1, AIF1, SLC7A2, TRAF1, S100A4, SLC9A9, CRIP1, CLEC7A, CLEC10A, EGR2, MGL2, SOCS2, CTLA2B, and FCGR1. Conclusion We have identified genes associated with T cell and macrophage activation that were down regulated in the 7D Cuff-off versus 14D Cuff-off and 28D mice; future studies in isolated T cells and macrophages will determine whether these genes represents biomarker(s) of renal disease progression in 2K-1C renovascular hypertension.

Aim The aim of this is to identify the gene expression profiles indicative of reversible versus irreversible injury in experimental (murine) renal artery stenosis (RAS). Method Two‐kidney‐one‐cuff hypertension was established by placement of a polytetrafluoroethylene cuff on the right renal artery (N=18). Sham surgery was performed by manipulating the right renal artery without cuff placement (N=6). To determine potential reversibility, the cuff was removed at 7 days (7D cuff‐off, N=6) and 14 days (14D cuff‐off, N=6) after initial RAS surgery. In a control RAS group, the cuff was left in place for 28 days (28D RAS, N=6). Kidneys were harvested at 28 days for assessment of atrophy and fibrosis. Renal blood perfusion and oxygenation were measured using 16.4T MRI. RNASeq analysis was performed on all the groups at 28 days following initial surgery. Results Following cuff placement, intra‐renal perfusion was reduced by 65% (p<0.0001 vs. baseline). In the 7D cuff‐off group intra‐renal perfusion was restored to baseline values after cuff removal, whereas in the 14D cuff‐off group perfusion was not significantly improved following cuff removal. In the 28D RAS group the reduction in perfusion was maintained throughout the study period. The 7D cuff‐off group had a significantly lower % atrophy (7 ± 2.2%, p=0.0042) and % area of interstitial fibrosis (0.57 ± 0.08 %, p<0.0001) compared to 28D RAS group (atrophy 66 ± 13%, area of fibrosis 7.79 ± 0.89 %). The 14D cuff‐off group had severe atrophy (56 ± 16.6%) and interstitial fibrosis (5.05 ± 1.22%) similar to that seen in 28D RAS group. RNASeq analysis data were normalized to appropriate sham controls in all the groups and was performed at 28 days following initial surgery. Induction of greater than Log2 ratio >2 and p values < 0.00001 were considered significant (following adjustment for multiple comparisons). Fibrosis associated genes were differentially regulated in the 7D cuff‐off compared to the 14D cuff‐off and 28D RAS group (table ). Conclusion We conclude that cuff removal at 7 days is associated with relative preservation of renal structure, indicating that renal injury at this point is reversible. We have identified a number of fibrosis associated genes that are differentially regulated in the 7D cuff‐off group versus 14D cuff‐off group. Further analysis will determine the functional relevance of these differentially regulated genes. Support or Funding Information This project was funded by National Institutes of Health, NIAID R01 AI100911. Values of Log 2 Ratio Genes 7D Cuff‐off vs Sham 14D Cuff‐off vs Sham 28D RAS vs Sham COL1A1 0.96 2.62 2.23 COL1A2 0.79 2.07 1.91 COL3A1 1.26 2.60 2.35 MMP12 1.24 2.85 2.95 MMP14 1.34 2.70 2.55 MMP19 2.89 3.86 4.05 MMP2 1.55 3.49 3.22 MMP7 6.96 9.22 9.59 MTOR −0.46 −1.67 −2.06 SERPINE1 1.25 3.37 2.35 TGFB1i1 0.44 1.46 1.53 TGFB2 0.82 1.83 1.97 TGFB3 0.59 1.91 1.99 TGFBi 0.98 1.88 2.02 KLF15 −0.90 −1.76 −2.60 UBD 4.49 6.23 6.18 TIMP1 2.94 5.30 5.16 TIMP2 0.50 1.46 1.52 TIMP3 −0.35 −1.26 −1.36 HSPB1 0.16 2.00 2.13 HSPB8 1.51 2.26 2.30 CCL2 3.44 4.89 4.31 CCL12 2.88 3.71 4.12 SERPINE1 1.25 3.37 2.35 SERPINE2 1.17 2.39 2.35 SERPINF1 2.02 2.76 3.11 SERPINF2 −0.51 −2.03 −2.71 SERPING1 1.15 1.81 2.09 CLU 1.45 2.54 3.07 STC1 0.45 1.99 2.12 SPP1 1.75 3.06 3.37

Telomere length (TL) is associated with cardiovascular disease (CVD) and cancer. Obstructive sleep apnea (OSA) is also linked to higher risk of CVD and cancer, and to TL. We investigated the association between TL and risk of major adverse cardiac events (MACE) and cancer in OSA patients. We studied 210 individuals undergoing sleep-related studies between 2000 and 2007. Baseline characteristics and follow-up data (available in 164 subjects) were obtained from clinic records. Incidence rates were calculated for the entire group and by OSA status. Hazard ratios were calculated to estimate effects of OSA and TL on risk of MACE and cancer. In total, 32 individuals (20%) developed MACE and/or cancer during 12.7-year follow-up. The OSA group had a higher likelihood of cancer (16.0 vs. 4.9 events per 1000 person-years, P = 0.044) but no clear evidence of an elevated incidence of MACE (10.8 vs. 4.8 events per 1000 person-years, P = 0.293) compared to the non-OSA group. There was no association between TL and MACE- (HR = 1.01, 95% CI 0.78–1.28), or cancer-risk (HR = 1.18, 95% CI 0.96–1.43). Our study warrants further investigation of any modulating effect of OSA on TL and the risk of MACE and cancer.

Obstructive sleep apnea (OSA) is associated with cardiometabolic diseases. Telomere shortening is linked to hypertension, diabetes mellitus, and cardiovascular diseases. Because these conditions are highly prevalent in OSA, we hypothesized that telomere length (TL) would be reduced in OSA patients. We identified 106 OSA and 104 non-OSA subjects who underwent polysomnography evaluation. Quantitative PCR was used to measure telomere length in genomic DNA isolated from peripheral blood samples. The association between OSA and TL was determined using unadjusted and adjusted linear models. There was no difference in TL between the OSA and non-OSA (control) group. However, we observed a J-shaped relationship between TL and OSA severity: the longest TL in moderate-to-severe OSA [4,918 ± 230 (SD) bp] and the shortest TL in mild OSA (4,735 ± 145 bp). Mean TL in moderate-to-severe OSA was significantly longer than in the control group after adjustment for age, sex, body mass index, hypertension, dyslipidemia, and depression (β = 96.0, 95% confidence interval: 15.4–176.6, P = 0.020). In conclusion, moderate-to-severe OSA is associated with telomere lengthening. Our findings support the idea that changes in TL are not unidirectional processes, such that telomere shortening occurs with age and disease but may be prolonged in moderate-to-severe OSA. NEW & NOTEWORTHY Here, we show that moderate-to-severe obstructive sleep apnea is associated with longer telomeres, independent of age and cardiovascular risk factors, challenging the hypothesis that telomere shortening is a unidirectional process related to age/disease. A better understanding of the mechanisms underlying telomere dynamics may identify targets for therapeutic intervention in cardiovascular aging/other chronic diseases.

Abstract Despite advances in prevention and early detection strategies, colorectal cancer (CRC) remains the second leading cause of cancer death in the United States. The majority of CRC arises from adenomatous polyps. However, only 5% of all people who receive a colonoscopy will have a lesion determined to be at high risk for malignant transformation. Adenomas are primarily classified based on histology, size, degree of dysplasia and limited genetic mutation information. Further characterization of what contributes to or underlies the malignant transformation of polyps is currently lacking, but is essential to further understand the transition from polyp to cancer and factors that lead only a small portion of polyps to progress onto cancer. Although telomere length is a recognized biomarker in multiple cancers, few studies have addressed the comprehensive role of telomeres in CRC progression. Telomere shortening is a fundamental feature of dividing cells related to the age of the cell and is implicated in carcinogenesis. Telomere length is not solely determined by attrition resulting from cell division, but also through telomere maintenance mechanisms (TMM), which are often exploited in malignant cells. In this study, we will measure the telomere profile (consisting of telomere length and TMM) in normal colon epithelium, polyps and the adjacent tumor trios and normal colon epithelium and cancer-free polyp pairs. Our aim is to determine which telomere features distinguish cancer adjacent polyps from cancer free polyps. This is an innovative approach for identifying the definable telomere-related properties that distinguish polyps with malignant potential that remain benign from those that transform to cancer and progress to invasive lesions. Further characterization of the molecular profile of polyps undergoing the transition to cancer that differentiate cancer free polyps has the potential to be utilized in designing optimal treatment options for patients with polyps that carry the risk of CRC. Citation Format: Brooke R. Druliner, Ruth Johnson, Xiaoyang Ruan, Russell Vanderboom, Donna Felmlee Devine, Jill Washechek Aletto, Lisa A. Boardman. Time lapse to cancer: Defining the transition from polyp to colorectal cancer based on telomere metrics. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-04.

Abstract Introduction: Activation of telomerase and telomere lengthening in patient peripheral blood leukocytes (PBL) is associated with longer survival in cancer patients. There are few studies to date that have measured telomerase activity in clinical PBL samples, and it is unclear how initial collection and processing of PBL samples impact the measurement of telomerase activity. In this study, we assessed if telomerase activity measurement varies based on the method of blood collection, processing and storage. Methods: We first collected whole blood drawn in EDTA tubes from two healthy patients that were then processed three different ways. The first whole blood sample was spun down and the buffy coat was pipetted from the top of the red blood cells, and then placed directly into the -80°C freezer. The next two whole blood samples were isolated using an ACCUSPIN™ tube, which utilizes density gradient separation to recover the PBL without contamination of red blood cells. The resulting PBL from these two samples were suspended in freezing media containing RPMI and DMSO, with one sample also containing penicillin streptomycin glutamine, and then both samples were stored in liquid nitrogen following a slow freeze. We then measured enzymatic telomerase activity in each of the three PBL samples from the two different patients. Results: We detected a comparable level of telomerase activity in all three PBL samples. These findings indicate that telomerase activity can be measured in buffy coat samples from patients independent of how the samples were processed and stored. Conclusions: These findings are important because many biorepositories may not have collected or processed PBL samples by identical processes, therefore not allowing direct comparison across samples. Additionally, our finding that telomerase activity levels are comparable between PBL samples containing red blood cells and those processed using an ACCUSPIN™ tube is valuable because it eliminates the necessity for the extra cost of the ACCUSPIN™ tube, freezing media, antibiotics and use of liquid nitrogen storage tanks. Future studies will focus on the determining the relationship of telomerase activity between the PBL, normal colon and cancer tissue in colorectal cancer patients. Citation Format: Ruth A. Johnson, Brooke R. Druliner, Jill Washechek Alleto, Donna Felmlee Devine, Xiaoyang Ruan, Russell Vanderboom, Lisa A. Boardman. How collection, processing and storage of PBL samples impact the measurement of telomerase activity. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B1-46.

Abstract Introduction: Peripheral blood leukocyte (PBL) telomere length is associated with colon cancer (CC) risk, but the relationship of PBL telomere length to survival in CC patients receiving chemotherapy is unknown. Methods: We measured relative telomere length (RTL) by qPCR of PBL DNA from 2,748 cases (53% male, 85% white, median age 58 yrs) in the North American Phase III Intergroup Trial N0147 that compared disease-free survival (DFS) among completely resected Stage III CC treated with mFOLFOX6 +/- cetuximab. Tumor markers were assessed, and 12% were BRAF mutant; 35% Kras mutant, and 12% deficient mismatch repair (dMMR). Linear and non-linear prognostic associations of PBL RTL to the primary endpoint of DFS were assessed by Cox models. Optimal categories of RTL were developed using cumulative martingale residual plots, designated from shortest to longest RTL (Table 1). Results: Never smokers had longer PBL RTL (p = 0.0006) than past or current smokers. Those with diabetes mellitus (DM) had longer PBL RTL than those without DM (p = 0.0165). PBL RTL was not associated with any tumor markers (MMR status; p = 0.7174; BRAF mutant vs wild-type (wt); p =0.4039; Kras mutant vs wt; p= 0.1149). PBL RTL was significantly associated with DFS in a non-linear form (p = 0.0389). Cases in the longer RTL category had more favorable DFS than those with shorter or longest RTL, (Table), which remained after adjusting for age, sex , T/N stage, grade, tumor markers, and treatment (p = 0.0230). We observed no significant interaction (p = 0.1490) between RTL categories and treatment. Conclusion: We observed a non-linear association between RTL and DFS in stage III CC, suggesting that an optimal range telomere length can influence tumor behavior in CC patients. Future studies of telomere maintenance mechanisms may help to explain the association of RTL with improved DFS. RTL is associated with smoking and DM in CC cases but further studies are needed to determine if either tobacco use or DM affect survival from CC by modulating PBL telomere length. Citation Format: Nivedita Basu, Ruth A. Johnson, Qian Shi, Garth D. Nelson, Julie M. Cunningham, Richard M. Goldberg, Frank A. Sinicrope, Daniel J. Sargent, Steven R. Alberts, Gloria M. Petersen, Stephen N. Thibodeau, Halcyon G. Skinner, Kristin Litzelman, Songwon Seo, Russell J. Vanderboom, Ronald E. Gangnon, Corinne D. Engelman, David N. Rider, Lisa A. Boardman. Telomeres and survival in stage III colon cancers: Findings from NCCTG N0147 (Alliance) study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5102. doi:10.1158/1538-7445.AM2014-5102