Carlos Girod

Telomere Lengths, Pulmonary Fibrosis and Telomerase (TERT) Mutations

Background Telomerase is an enzyme that catalyzes the addition of nucleotides on the ends of chromosomes. Rare loss of function mutations in the gene that encodes the protein component of telomerase (TERT) have been described in patients with idiopathic pulmonary fibrosis (IPF). Here we examine the telomere lengths and pulmonary fibrosis phenotype seen in multiple kindreds with heterozygous TERT mutations. Methods and Findings We have identified 134 individuals with heterozygous TERT mutations from 21 unrelated families. Available medical records, surgical lung biopsies and radiographs were evaluated retrospectively. Genomic DNA isolated from circulating leukocytes has been used to measure telomere lengths with a quantitative PCR assay. We find that telomere lengths of TERT mutation carriers decrease in an age-dependent manner and show progressive shortening with successive generations of mutation inheritance. Family members without TERT mutations have a shorter mean telomere length than normal, demonstrating epigenetic inheritance of shortened telomere lengths in the absence of an inherited TERT mutation. Pulmonary fibrosis is an age-dependent phenotype not seen in mutation carriers less than 40 years of age but found in 60% of men 60 years or older; its development is associated with environmental exposures including cigarette smoking. A radiographic CT pattern of usual interstitial pneumonia (UIP), which is consistent with a diagnosis of IPF, is seen in 74% of cases and a pathologic pattern of UIP is seen in 86% of surgical lung biopsies. Pulmonary fibrosis associated with TERT mutations is progressive and lethal with a mean survival of 3 years after diagnosis. Overall, TERT mutation carriers demonstrate reduced life expectancy, with a mean age of death of 58 and 67 years for males and females, respectively. Conclusions A subset of pulmonary fibrosis, like dyskeratosis congenita, bone marrow failure, and liver disease, represents a “telomeropathy” caused by germline mutations in telomerase and characterized by short telomere lengths. Family members within kindreds who do not inherit the TERT mutation have shorter telomere lengths than controls, demonstrating epigenetic inheritance of a shortened parental telomere length set-point.

Exome sequencing links mutations in PARN and RTEL1 with familial pulmonary fibrosis and telomere shortening

Idiopathic pulmonary fibrosis (IPF) is an age-related disease featuring progressive lung scarring. To elucidate the molecular basis of IPF, we performed exome sequencing of familial kindreds with pulmonary fibrosis. Gene burden analysis comparing 78 European cases and 2,816 controls implicated PARN, an exoribonuclease with no previous connection to telomere biology or disease, with five new heterozygous damaging mutations in unrelated cases and none in controls (P = 1.3 × 10−8); mutations were shared by all affected relatives (odds in favor of linkage = 4,096:1). RTEL1, an established locus for dyskeratosis congenita, harbored significantly more new damaging and missense variants at conserved residues in cases than in controls (P = 1.6 × 10−6). PARN and RTEL1 mutation carriers had shortened leukocyte telomere lengths, and we observed epigenetic inheritance of short telomeres in family members. Together, these genes explain ∼7% of familial pulmonary fibrosis and strengthen the link between lung fibrosis and telomere dysfunction.

Effect of telomere length on survival in patients with idiopathic pulmonary fibrosis: an observational cohort study with independent validation

BACKGROUND Short telomere lengths are found in a subset of patients with idiopathic pulmonary fibrosis, but their clinical significance is unknown. Our aim was to investigate whether patients with various blood leucocyte telomere lengths had different overall survival. METHODS In this observational cohort study, we enrolled patients with interstitial lung disease from Dallas, TX (primary cohort), and from Chicago, IL, and San Francisco, CA (replication cohorts). We obtained genomic DNA samples from unrelated healthy controls in Dallas, TX, and spouses of patients were also enrolled as an independent control group. Telomere lengths were measured in genomic DNA samples isolated from peripheral blood obtained at the time of the initial enrolment assessment. The primary endpoint was transplant-free survival (ie, time to death or lung transplantation) in the Dallas cohort. Findings were validated in the two independent idiopathic pulmonary fibrosis cohorts (Chicago and San Francisco). FINDINGS 370 patients were enrolled into the Dallas cohort between June 17, 2003, and Aug 25, 2011. The 149 patients with idiopathic pulmonary fibrosis had shorter telomere lengths than did the 195 healthy controls (mean age-adjusted log-transformed ratio of telomere to single copy gene was -0.16 [SD 0.23] vs 0.00 [0.18]; p<0.0001); however, telomere lengths of the Dallas patients with idiopathic pulmonary fibrosis (1.33 [SD 0.25]) were similar to the 221 patients with other interstitial lung disease diagnoses (1.46 [0.24]) after adjusting for age, sex, and ethnicity (p=0.47). Telomere length was independently associated with transplant-free survival time for patients with idiopathic pulmonary fibrosis (HR 0.22 [95% CI 0.08-0.63]; p=0.0048), but not for patients with interstitial lung disease diagnoses other than idiopathic pulmonary fibrosis (HR 0.73 [0.16-3.41]; p=0.69). The association between telomere length and survival in patients with idiopathic pulmonary fibrosis was independent of age, sex, forced vital capacity, or diffusing capacity of carbon monoxide, and was replicated in the two independent idiopathic pulmonary fibrosis replication cohorts (Chicago cohort, HR 0.11 [0.03-0.39], p=0.00066; San Francisco cohort, HR 0.25 [0.07-0.87], p=0.029). INTERPRETATION Shorter leucocyte telomere lengths are associated with worse survival in idiopathic pulmonary fibrosis. Additional studies will be needed to establish clinically relevant thresholds for telomere length and how this biomarker might affect risk stratification of patients with idiopathic pulmonary fibrosis. FUNDING US National Heart, Lung, and Blood Institute, National Center for Advancing Translational Sciences, Harroun Family Foundation, and Nina Ireland Lung Disease Program.

Therapeutic plasma exchange in the management of sepsis and multiple organ dysfunction syndrome: A report of three cases

Sepsis with multi organ dysfunction syndrome (MODS) is the most common cause of death in patients in noncoronary intensive care units. Currently, there are no specific treatments that reduce mortality in patients with sepsis and MODS. We report three patients who received therapeutic plasma exchange (TPE) for sepsis with MODS who completely recovered. The first patient, a 3‐year‐old male presented with Methicillin‐resistant Staphylococcus aureus‐associated respiratory, renal, coagulation, hepatic, and neurologic dysfunction. After 5 TPEs, the patient fully recovered. The second patient was a 36‐year‐old pregnant female who developed MODS at 22 weeks of gestation. She had developed respiratory, hepatic, renal, cardiovascular, neurologic, and coagulation dysfunction following pneumonia and concurrent urinary tract infection resulting in an intrauterine fetal demise. After 8 TPEs, the patient was discharged home with only mild residual hepatic dysfunction. The third patient, a 50‐year‐old female with a history of seizure disorder, was found unresponsive in over 100°F heat and diagnosed with Staphylococcus aureus‐associated MODS. Her respiratory, coagulation, neurologic, renal, and hepatic systems were affected. The patient underwent 6 TPEs after which she had marked improvement. In conclusion, TPE may be an effective adjunct therapy in MODS by possibly removing toxic mediators and replacing deficient factors using donor plasma. J. Clin. Apheresis 29:127–131, 2014.

Thoracic Cavernous Lymphangioma Provoking Massive Chyloptysis: A Case Report

Chyloptysis is a relatively rare embodiment of disease that encompasses a lengthy differential and provides many diagnostic and therapeutic challenges. Presented here is the case of a young woman with massive chyloptysis due to a thoracic cavernous lymphangioma arising in the peripartum period. The severity of her condition mandated the use of cardiopulmonary bypass to resect her lymphangioma. We believe that the extent of her symptoms, etiology of disease, and surgical management represent a unique scenario in the literature.

Sepsis at a Safety Net Hospital: Risk Factors Associated With 30-Day Readmission

Background: Sepsis is a leading cause of hospitalization, and subsequent readmissions are frequent and costly. There is an expanding body of literature describing risk factors for readmissions in patients with sepsis. However, there are little data studying medically underserved patients who typically receive their care at a safety net hospital. Methods: In a retrospective cohort study, we evaluated 1355 sepsis survivors at risk of hospital readmission in fiscal year 2013 at a safety net hospital. We described patient characteristics during their initial and readmission hospitalizations and analyzed risk factors associated with 30-day readmission. Results: The 30-day readmission rate among sepsis survivors was 22.6%. Comorbid conditions associated with readmissions included end-stage renal disease (odds ratio [OR], 1.26; 95% confidence interval [CI], 1.17-1.36), malignancy (OR, 1.14; 95% CI, 1.08-1.21), and cirrhosis (OR, 1.11; 95% CI, 1.02-1.20). Bacteremia during the initial hospitalization (OR, 1.07; 95% CI, 1.01-1.15) and being discharged with a vascular catheter (OR, 1.10; 95% CI, 1.01-1.20) were associated with readmission. Less severe sepsis during the initial hospitalization was associated with a reduced risk of 30-day readmission (OR, 0.91; 95% CI, 0.87-0.94). Conclusions: At a safety net hospital, patients who survived their initial sepsis hospitalization had a 30-day readmission rate to our institution of 22.6% that is comparable to rates described in prior studies. Readmission was commonly due to infection. Factors associated with readmission included multiple comorbid medical conditions, bacteremia, and being discharged with a vascular catheter. Further studies in this population are needed to determine potential modifiability of these risk factors in an attempt to reduce sepsis readmissions.