A common polymorphism of the glucocorticoid-receptor gene is related to outcome of intensive care therapy

A common polymorphism of the glucocorticoid-receptor gene is related to traumatic
memories and post-traumatic stress disorder in patients after intensive care therapy
Daniela Hauera/# MD; Florian Weisa/# MD; Andreas Papassotiropoulosc,d MD; Michael Schmoeckele MD; Julia Liekea MS; Ines Kaufmanna MD; Fabian Kirchhoffg; Michael Voge- serg MD; Benno Roozendaalb PhD; Josef Briegela MD; Dominique de Quervainf MD and Department of Anaesthesiologya, Cardiac Surgerye and Clinical Chemistryg, Ludwig- Maximilians University, Munich, Germany; Department of Neuroscience, Section Anatomyb, University Medical Center Groningen, University of Groningen, The Netherlands; Division of Molecular Psychologyc, Life Sciences Training Facilityd, Biozentrum; University of Basel, Switzerland; Division of Cognitive Neurosciencef, University of Basel, Switzerland Florian Weis, MD Ludwig – Maximilians University Klinikum Grosshadern Department of Anaesthesiology 81377 Muenchen; Germany Phone: +49-89-7095-0 (operator) Fax: +49-89-7095-8886 e-mail: [email protected] This study was supported by the Else Kröner-Fresenius Stiftung, the European Science Foun- dation (BALANCE) and in part by the Swiss National Science Foundation (grants PP00B- Key words: glucocorticoid receptor gene; genetic polymorphism; traumatic memories; stress; post-traumatic stress disorder; outcome; #both authors contributed equally to this work Abstract
Objective: Glucocorticoids play a major role in the consolidation and retrieval of traumatic
information. They act through the glucocorticoid receptor (GR) for which, in humans, several polymorphisms have been described. In particular, the BclI single-nucleotide polymorphism (SNP) is associated with hypersensitivity to glucocorticoids and with susceptibility to devel- opment of major depression. Furthermore, in patients with post-traumatic stress disorder (PTSD) carrying the BclI GG genotype, cortisol levels were lower and showed an inverse relationship to PTSD-symptom intensity. Here, we studied the association of the BclI poly- morphism with plasma cortisol levels, traumatic memories, PTSD symptoms and health- related quality of life (HRQL) outcomes in 126 patients undergoing cardiac surgery (CS) and Design: Prospective observational study.
Setting: Cardiovascular intensive care unit in a university hospital.
Patients: 126 patients undergoing CS and ICU treatment.
Interventions: No intervention was performed.
Measurements and Main Results: Validated questionnaires were used to quantify endpoints.
Measurements were taken 1 day before, 1 week and 6 months after CS. Homozygous carriers of the BclI G-allele (BclI*G, n=21) had significantly lower preoperative plasma cortisol lev- els and more long-term traumatic memories from ICU-therapy at 6 months post-CS than het- erozygous or non-carriers (1.9+1.4 vs. 1.0+1.2, p=0.01). Anxiety was significantly more common as a long-term traumatic memory in homozygous BclI*G carriers than in heterozy- gous or non-carriers (57% vs. 35%, p=0.03). PTSD-symptom scores were significantly higher at discharge from ICU in homozygous BclI*G carriers than in heterozygous or non-carriers. Only heterozygous or BclI*G non-carriers had a significant gain in HRQL physical function at 6 months post-CS (p<0.01). Baseline values were not statistically different between carriers Conclusion: Homozygous BclI*G carriers are at risk for traumatic memories, PTSD symp-
toms and lower HRQL after CS and ICU-therapy. The BclI SNP may help to identify indi- viduals at need for tailored medical care. Introduction
Animal and human studies have repeatedly shown that glucocorticoids influence memory in situations of acute and chronic stress (1-3). Glucocorticoids are known to enhance memory consolidation of emotionally arousing experiences (4, 5) but impair memory retrieval under stressful conditions (6, 7). Persistent traumatic memories of highly stressful experiences are a hallmark of stress-related disorders such as post-traumatic stress disorder (PTSD) and changes in glucocorticoid signaling have consistently been demonstrated in humans with PTSD (8-10) as well as in animal models of the disorder (11). In critically ill patients, traumatic memories from treatment in an intensive care unit (ICU) can be associated with PTSD stress symptoms and are influenced by the administered dosages of catecholamines and glucocorticoids in the ICU (12-14). Glucocorticoids influence cognitive and emotional processes through the gluco- corticoid receptor (GR) and changes in GR sensitivity have been shown in patients with PTSD (10, 15) as well as other stress-related disorders such as depression (16). In humans, several single nucleotide polymorphisms (SNPs) of the GR gene have been described which influence GR sensitivity (17, 18). Among these SNPs, the BclI polymorphism, which involves a restriction site in intron 2, 646 base pairs downstream from exon 2, of the GR gene and con- sists of a C to G nucleotide change (BClI GG), is associated with hypersensitivity to glucocor- ticoids. This hypersensitivity has been documented by an increased suppression of adrenocor- ticotropin and cortisol levels following a low-dose dexamethasone challenge (19, 20) and a metabolic profile suggestive of GR hypersensitivity, including an increased risk for cardio- We performed a hypothesis-driven study in patients with cardiovascular disease undergoing CS to investigate whether patients homozygous for the BclI G-allele (BclI *G), which has been associated with higher GR sensitivity, have more traumatic memories from ICU treat- ment and more marked PTSD stress symptoms than heterozygous or non-carriers of this al- Patients and Methods
Patient selection and study design Between July 6, 2004 and July 1, 2005 we prospectively screened all adult patients (>18 years) scheduled for heart surgery at the Department of Cardiac Surgery of the University of Munich for possible inclusion into our study. Inclusion criteria were planned coronary artery bypass grafting or cardiac valve replacement. Exclusion criteria were combined coronary ar- tery and valve disease, emergency procedures, severe alcohol or drug abuse, major pre- existing neurologic disease or psychiatric illness (e.g. major depressive or bipolar disorder, PTSD, somatoform disorder), current use of steroids and severe comorbidities such as chronic organ dysfunction (renal, liver or pulmonale) or cancer. Patients not qualified for study inclu- sion fulfilling the abovementioned exclusion criteria were identified by chart review, patient interview, and direct communication with the attending cardiac surgeons or the private physi- Eligible patients were evaluated for standardized traumatic memories and PTSD-symptom scores at study inclusion and then followed prospectively. Plasma cortisol levels were meas- ured pre- and postoperatively. Reevaluation for traumatic memories from ICU treatment and the development of PTSD stress symptoms was performed 1 week after discharge from the ICU and at 6 months thereafter. Plasma cortisol concentrations, traumatic memories and PTSD stress-symptom intensities were then compared between homozygous and heterozy- The study was approved by the Institutional Review Board of the Ludwig-Maximilians Uni- versity of Munich (protocol #198/99 and #140/99) and data protection met the standard set by German law. Written informed consent was obtained from all subjects (including an addition- General patient assessment consisted of demographics, a detailed evaluation of type and se- verity of cardiac disease, intraoperative data (e.g. duration of surgery and cardiopulmonary bypass) and the prospective recording of predefined ICU treatment variables, including the use and dosages of epinephrine, beta-adrenergic antagonists, glucocorticoids and the sedative drugs midazolam and propofol. These drugs were selected for documentation and analyses because possible effects of these substances on traumatic memory and PTSD symptoms after ICU treatment have previously been described (12). One day before their scheduled operation, the patients were approached by trained research assistants and received a detailed explanation of the purpose of the study. The patients were informed that we were interested in their present and postoperative state of physical and men- tal health, without any direct referral to traumatic memories or PTSD symptoms. After in- formed consent, the patients completed validated questionnaires evaluating standardized traumatic memories and chronic stress symptoms including those of PTSD. One week after discharge from the ICU, while in the normal cardiovascular ward, the patients were approached again and asked to complete the same instruments on traumatic memories from the ICU and PTSD-related symptoms as they did preoperatively. At 6 months after CS, the patients were contacted by phone and, after repeated oral consent, received the same set of Quantification of traumatic memories and PTSD symptoms All patients completed a standardized and validated questionnaire evaluating different catego- ries of traumatic memory and PTSD symptoms from ICU treatment (22). The questionnaire consists of two parts: Part A evaluates four standardized categories of traumatic memory from the ICU and Part B quantifies the presence and intensities of 10 PTSD-related symptoms. This questionnaire has been validated in patients after ICU therapy (22) and used in several other studies in patients after ICU therapy or CS (14, 23-26). A category of traumatic memory as measured by Part A of the questionnaire was defined as the patient’s subjective recollection of (1) nightmares, (2) respiratory distress/dyspnea, (3) feelings of anxiety/panic or (4) pain at anytime between 1 week before CS and 1 week after discharge from the ICU. When completing the questionnaire, the patients were asked to an- swer each of these four items “yes” or “no,” independent of the number of occasions the ad- verse experience occurred (only frequencies were scored). The number with which these four items is answered “yes” by a subject is termed the number of categories of traumatic memory. The intensity of traumatic memories was not specifically evaluated. The severity and presence of PTSD symptoms was quantified by Part B of the questionnaire. This part of the questionnaire resulted from a modification of the Post-Traumatic Stress Symptom 10-Questions (PTSS-10) instrument (27) and evaluates the presence and intensity of 10 PTSD-related stress symptoms: (1) sleep disturbance, (2) nightmares, (3) depression, (4) hyperalertness, (5) withdrawal (emotional numbing and inability to care for others), (6) gene- ralized irritability, (7) frequent changes in mood, (8) guilt, (9) fear and avoidance reactions with regard to the ICU, and (10) increased muscle tension. When evaluating these symptoms, the patients were asked to think back to the last few days (“presently— that means in the past few days—I suffer from. . .”), and then they were asked if they had symptoms expressed by statements such as: “Jumpiness, I am easily frightened by sudden sounds or sudden move- ments” (to evaluate hyperalertness), “fear of places and situations which remind me of the intensive care unit” (to evaluate avoidance reactions), or “a bad conscience, blame myself, have guilt feelings” (to evaluate guilt). Patients rated their symptoms using a scale from 1 (never) to 7 (always). A summary score could then be calculated that ranges from 10 to 70 points, with increasing scores indicating a higher prevalence and intensity of PTSD symp- toms. The questionnaire has been specifically validated in patients after ICU therapy using a double-blind interview performed by psychiatrists. The interviews were performed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria to diagnose PTSD. This validation process demonstrated a high internal consistency (Crohn- bach´s α=0.93) and a high test-retest reliability (intraclass correlation coefficient r=0.89) of the instrument. The specificity and sensitivity for diagnosis of PTSD after ICU treatment at a cut-off value of 35 points of the questionnaire was 97.5% and 77%, respectively (22). Health-related quality of life and chronic pain Health-related quality of life (HRQL) was measured using the German version of the self- administered Medical Outcomes Study Short Form Survey that consists of 36 questions (SF- 36) (28). Pain intensities were determined by using a visual analogue scale ranging from 0 to 10 where 0 indicated no pain and 10 the worst imaginable pain (VAS pain scores). Pain and HRQL measurements were performed at the preoperative visit and at 6 months after surgery. After enrollment into the study, 10 ml of blood was collected in EDTA-coated tubes from each patient. Blood samples were kept frozen at -20 ºC. Genotyping was performed in those patients who had a complete set of questionnaires across all 3 time points of measurements at Genomic DNA was extracted using the QIAamp DNA blood maxi kit (Qiagen, Hilden, Ger- many). Information on the BclI polymorphic site of the GR was derived from the database of single-nucleotide polymorphisms (dbSNP) established by the National Center for Biotechnol- ogy Information (http://www.ncbi.nlm.nih.gov/SNP/ index.html). Genotyping was done with Pyrosequencing on a PyroMark™ID System (Biotage, Uppsala, Sweden). Primers for the BclI polymorphism were: 5’-CTT GCA GAA GAG GAT TCA CAT CA-3’ (forward, 5’- biotinylated), 5’- GTG TGT CTG CCT GAA GGA ATG-3’ (reverse), 5’- GTG TAT CTC AGA AAA GAC CT-3’ (sequencing). Primers for rs3781230 were: 5’-AGG TCT TGC TCA CAG GGT TCT T-3’ (forward), 5’-TTT TGC ACC ATG TTG ACA CCA-3’ (reverse, 5' bio- tinylated), 5’-ACA AGT TAT GTC TGC TGA T-3’ (sequencing primer). Genotype distribu- tions were in Hardy-Weinberg equilibrium. Measurement of plasma cortisol levels Blood sampling for cortisol measurements were performed between 7 and 8 am at the preo- perative time point and in the morning of the first postoperative day. Plasma cortisol levels were measured by isotope dilution liquid chromatography tandem mass spectrometry (LC– MS/MS) as previously described by our group (29). Twenty-nine patients from the study sample received hydrocortisone after the preoperative time point at induction of anesthesia (Table 2). The use of hydrocortisone was not randomized but left to the discretion of the attending anesthesiologists. Hydrocortisone was administered starting with a loading dose (100 mg over 10 min), followed by a continuous infusion of 10 mg/h for 24 h (postoperative day 1 = POD 1), which was reduced to 5 mg/h on POD 2, and then tapered to 3 x 20 mg, i.v. on POD 3, and 3 x 10 mg i.v. on POD 4. Stress doses of hydro- cortisone given during the first 24 h were calculated to be approximately equivalent to the endocrine secretion rate of the adrenal glands under maximal stimulation (30). All variables were tested for normal distribution using the Kolmogorov-Smirnov test. For the initial statistical analyses and in order to increase statistical power, heterozygous and non- carriers of the BclI *G SNP were combined into one group and compared to the second group of homozygous BclI *G carriers. Normally distributed continuous variables between homozy- gous and heterozygous/non BclI *G carriers were compared by t–tests. Nonparametric data were compared by the Mann-Whitney U test. In order to delineate possible gene-dose effects, additional comparisons between non-carriers, heterozygous and homozygous subgroups were performed when the differences between combined groups were significant. For these com- parisons, analysis of variance (ANOVA) in normally distributed data and Kruskal-Wallis One Way Analysis of Variance on Ranks in nonparametric data with Fischer´s LSD post-hoc test was used. Cortisol measurements were transformed to log10 before comparison because un- transformed values were skewed. The log cortisol was normally distributed. Discrete variables were analyzed with the Chi2- or Fisher’s exact test, when appropriate. All statistical calcula- tions were performed using the SPSS 17.0 statistical package (SPSS Inc., Chicago, Il, USA). Results are expressed as mean ± standard deviation (SD). In graphs, mean ± SEM is shown to improve clarity. A p value <0.05 was considered as statistically significant for all compari- One-hundred-and-fifty patients were initially included into the study. Of these patients, 13 (8.7%) had died during post-operative ICU treatment, 137 individuals had complete question- naires at 1 week after discharge from the ICU. A further 11 (8.0%) patients died during the follow-up period and 126 patients returned complete questionnaires at 6 months after CS. These 126 individuals represent the final study population and were subjected to genotyping. Fifty-one patients (40.5%) were non-carriers of the BclI *G, 54 (42.9%) were heterozygous BclI *G carriers and 21 (14%) were homozygous. Heterozygous and non-carriers were com- bined into one group (n=105) and compared to the homozygous group (n=21). Baseline and treatment variables did not differ significantly between both groups and are shown in detail in Differences between homozygous and heterozygous/non-carriers of the BclI *G Homozygous BclI *G carriers had lower basal plasma concentrations and showed no increase in plasma cortisol when receiving stress doses of hydrocortisone At the preoperative time point, homozygous carriers of the BclI *G had significantly lower log10 transformed plasma cortisol levels than heterozygous/non-carriers with no significant postoperative differences in plasma cortisol concentrations (Figure 1). A subgroup analysis with regard to the BclI *G alleles using ANOVA with Fischer´s LSD post-hoc test revealed no significant difference in preoperative log10 transformed plasma cortisol levels between heterozygous and non-carriers (mean difference=-0.05+0.09, p=0.64), but a significant differ- ence between homozygous BclI *G carriers and heterozygous individuals (mean difference=- 0.25+0.12, p=0.03) and a strong trend towards higher cortisol levels in non-carriers compared to homozygous patients (mean difference=-0.21+0.12, p=0.07). Twenty-three of the 105 heterozygous/non-carriers of the BclI*G SNP had received stress doses of hydrocortisone after the preoperative time point vs. 6 of the 21 homozygous carriers. Heterozygous/non-carriers who had received hydrocortisone had significantly higher log10 transformed plasma cortisol levels than heterozygous/non-carriers who were not treated with glucocorticoids (1.3+0.4 vs. 1.0 +0.4 µg/dl, p=0.02). In homozygous individuals, the use of hydrocortisone did not result in increased plasma cortisol levels and log10 cortisol plasma concentrations in homozygous individuals with and without the administration of hydrocorti- sone were nearly identical (1.0+0.6 vs. 1.0+0.5 µg/dl, p=0.99). Homozygous BclI *G carriers had more traumatic memories from ICU therapy The number of recollected traumatic memories from ICU therapy differed significantly be- tween homozygous and heterozygous/non-carriers. Individuals homozygous for the BclI *G SNP had nearly double the number of traumatic memories from ICU treatment at 6 months as had heterozygous/non-carriers (1.9+1.4 vs. 1.0+1.2, p=0.01) with no significant differences at the other two time points (p>0.25, Figure 2). Additional comparisons between non-carriers, heterozygous and homozygous subgroups revealed a gene-dose effect. When compared to non-carriers, heterozygous BclI *G individuals had a higher number of traumatic memories (mean difference to non-carriers: 0.3+0.3), this difference was, however, not statistically sig- nificant (p=0.23). The difference between homozygotes and non-carriers (mean differ- ence=1.1+0.4, p<0.01) as well as the difference to heterozygotes (mean difference: 0.8+0.4, p<0.05) was significant (Figure 3). Anxiety during ICU therapy was significantly more often remembered at 6 months after surgery by homozygous BclI *G carriers than by heterozyg- ous/non-carriers (57% vs. 26% of all patients, p=0.03). Corresponding percentages for recol- lection of pain were 52% vs. 26%, for respiratory distress 38% vs. 26% and for nightmares 52% vs. 33% but these differences were not statistically significant (p>0.10). Homozygous BclI *G carriers had higher PTSD symptom scores after ICU therapy At the preoperative time point, there were no significant differences in PTSD symptom scores between groups. PTSD symptom scores were higher at 1 week after discharge from the ICU in homozygous BclI *G carriers than in heterozygous or non-carriers (25+11 vs. 19+9, p=0.02). Subgroup analyses according to the BclI *G carrier state revealed comparable PTSD symptom scores between non-carriers and heterozygotes (mean difference: -1.0+0.2, p=0.64) and significantly higher stress-symptom scores in homozygotes as compared to heterozygotes (mean difference: -5.4+2.6, p=0.04) and non-carriers (mean difference: -6.3+2.7, p=0.02). PTSD stress-symptom scores in the BclI *G homozygotes were still higher at 6 months after surgery but due to an increase in scores in the heterozygous/non-carrier group during the fol- low-up period this difference was no longer statistically significant (p=0.37, Figure 4). Four of 21 patients (19%) from the homozygous BclI *G group were above the 35 point cut-off value for diagnosis of PTSD vs. 11 from 105 individuals (10%) in the heterozygous/non- Homozygous BclI *G carriers had lower health-related quality of life outcomes SF-36 HRQL physical function summary scores at 6 months after surgery were significantly lower in homozygotes as compared to heterozygous or non BclI *G carriers (38.0±11.6 in homozygotes vs. 45.6±10.4 heterozygous or non-carriers, p=0.02). Subgroup analyses accord- ing to the BclI *G carrier state demonstrated a gene – dose effect. Homozygotes reported sig- nificantly lower physical function summary scores than heterozygous individuals (mean dif- ference=-7.36+3.6, p=0.04) and non-carriers (mean difference=-7.89+3.4, p=0.02). There were no other significant differences in HRQL outcomes between groups. Homozygous indi- viduals showed a trend towards higher VAS chronic pain scores at 6 months after surgery when compared to the heterozygous or non-carrier group (3.1±4.1 vs. 1.4±2.4, p=0.08). There were no significant preoperative differences in HRQL or VAS pain scores between carriers of Discussion
The main finding of this study is that homozygous BclI *G carriers are at an increased risk for adverse outcomes of CS and ICU therapy when compared to heterozygous or non-carriers of the BclI *G allele. This unfavorable outcome did not only include the presence of more trau- matic memories from the ICU and an associated increase in PTSD stress symptoms but also impairment in physical function and a trend towards a higher incidence of chronic pain. As this increased susceptibility of BclI GG carriers for the development of traumatic memories and PTSD-related stress symptoms became only evident after exposure to the stressful events of CS and ICU therapy, this effect may represent a gene-environment interaction. Homozygous BclI *G carriers had lower plasma cortisol levels During the moderately stressful preoperative period, homozygous BclI *G carriers showed significantly lower cortisol plasma levels. This finding is corroborated by another study which investigated healthy volunteers exposed to a standardized psychological laboratory stressor (the Trier Stress Test). Homozygous BclI *G allele carriers in this study showed a significant- ly lower cortisol response (31) which was more pronounced when the stress exposure was repeated (32). Interestingly, when BclI GG homozygotes in our study received stress doses of hydrocortisone, plasma cortisol levels did not increase whereas heterozygotes/non-carriers showed a significant augmentation of cortisol concentrations. The lower cortisol levels in ho- mozygous carriers of the BclI *G genotype could be due to an enhanced adrenal negative feedback action on the hypothalamus-pituitary-adrenal (HPA) axis (19), an increase in corti- sol metabolism or a combination of these and possibly other, unknown factors. In a well-characterized sample of Vietnam veterans with PTSD, the presence of the G-allele in the BclI gene was associated with lower basal cortisol levels and higher scores on the Clinican Administered PTSD Scale (CAPS) in a gene-dose dependent fashion. Furthermore, CAPS scores and basal cortisol levels were negatively correlated (33). Other recently de- scribed SNPs of the GR gene which enhance receptor responsiveness to cortisol (in particular the FKBP5 gene) resulted in a comparable phenotype in individuals with traumatic memories after exposure to a massive stressor (childhood maltreatment or the World Trade Center at- tack) with low basal cortisol levels (34) and an increased risk for PTSD (10). Homozygous BclI *G carriers had more traumatic memories and higher PTSD stress- Glucocorticoids play an important role in the regulation of emotional memory. Enhanced glu- corticoid signaling during stress has repeatedly been shown to strengthen the consolidation of emotionally arousing experiences (35) but to impair emotional memory retrieval (6, 36, 37). Moreover, glucocorticoids are known to have long-term facilitating effects on the extinction of traumatic memories (3). Homozygous BclI *G allele carriers show enhanced GR sensitivity (19) but lower basal cortisol concentrations. At the moment it is not entirely understood how this genotype resulted in an increased number of traumatic memories and higher PTSD stress- symptom scores. It is possible that the increased GR sensitivity of homozygous BclI *G allele carriers resulted in an enhanced consolidation of the traumatic experiences. On the other hand, it is also possible that the lower plasma cortisol levels found in homozygous BclI *G allele carriers facilitated the retrieval of traumatic memories accompanied by a failure to extinguish traumatic information (3). Both effects – and their interaction – could help to explain our find- ings. These assumptions are corroborated by a number of recent findings. One study indicated that long-term survivors of severe acute respiratory distress syndrome with septic shock and multiple traumatic memories from ICU therapy had significantly lower plasma cortisol levels and significantly higher PTSD-symptom scores (38). On the other hand, increasing cortisol levels by administering stress doses of hydrocortisone to critically ill patients undergoing CS as well as to patients with septic shock resulted in significantly lower PTSD stress-symptom scores and an improvement in HRQL outcomes in several controlled studies (13, 14, 39, 40). Likewise, low doses of hydrocortisone administered to individuals with PTSD of non-medical origin resulted in a significant improvement of memory-related PTSD symptoms in a small proof-of-concept study (41). These findings suggest that glucocorticoid signaling plays an important role in the formation and retrieval of traumatic memories and the development of PTSD symptoms in critically ill patients and that some of these effects may be mediated by genetic polymorphisms which influence GR sensitivity. Although we found evidence of lower plasma cortisol concentrations during preoperative stress and after the administration of hydrocortisone in the homozygous BclI GG carriers which could be due to enhanced HPA – axis feed back as a result of increased GR respon- siveness (19), we did not specifically test our patients for the presence for GR hypersensitivity but draw further evidence from several other, carefully performed studies. Increased glucocor- ticoid sensitivity with the GG phenotype is suggested by hyperinsulinemia, increased abdo- minal visceral fat, lower lean body mass (42-44) and the abovementioned increased negative feed back sensitivity of the HPA-axis (19). The increased risk for stress-related disorders after trauma exposure in the presence of a genetically determined GR hyperresponsiveness has been confirmed by other studies in different patient populations and with different GR SNPs (34, 45). Furthermore, the BclI polymorphism has highly tissue-specific effects and this, as mentioned above, could result in both, increased and decreased GR sensitivity in different tissues and different neuronal networks within the brain (31, 46), which makes it difficult to directly relate glucocorticoid signaling in different brain areas to specific neuropsychological findings. Furthermore, the BclI polymorphism is intronic and its effect on the GR gene may be indirect, serving only as a marker of other mutations affecting receptor function. There is, however, evidence that intronic polymorphisms are involved in the splicing process by, among other effects, changing the sequence of so-called intronic splicing silencers and en- hancers, and through other effects that are important for gene expression (47). And finally, despite the fact that our study was hypothesis driven and had a good rationale for the associa- tion under study and investigated a relatively large and homogenous cohort of patients ex- posed to a standardized stressor, the power of our study to exclude possible false positive as- sociations is still relatively low. Our findings need therefore replication in a larger study co- Regardless of these limitations, our findings support the notion that variants of the GR gene might influence traumatic memories, PTSD symptoms and HRQL after ICU therapy and that some of these outcome variables may positively respond to pharmacologic manipulation of glucocorticoid signaling. Preoperative genotyping of the GR may help to identify individuals Acknowledgement
This study is part of the dissertation of Julia Lieke at the Faculty of Medicine of the Ludwig- Maximilians University of Munich (in preparation). Financial Disclosures
There is no conflict of interest for any of the authors References
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The effect of stress doses of hydrocortisone during septic shock on posttraumatic stress disorder and health-related quality of life in survivors. Crit Care Med 1999;27(12):2678-2683. 40. Schelling G, Briegel J, Roozendaal B, et al. The effect of stress doses of hydrocortisone during septic shock on posttraumatic stress disorder in survivors. Biol Psychiatry 2001;50(12):978-985. 41. Aerni A, Traber A, Hock C, et al. Low-dose cortisol treatment reduces symptoms of post-traumatic stress disorder. Am J Psychiatry 2004;161:1488-1490. 42. Weaver JU, Hitman GA, Kopelman PG. An association between a Bc1I restriction fragment length polymorphism of the glucocorticoid receptor locus and hyperinsulinaemia in obese women. J Mol Endocrinol 1992;9(3):295-300. 43. Buemann B, Vohl MC, Chagnon M, et al. Abdominal visceral fat is associated with a BclI restriction fragment length polymorphism at the glucocorticoid receptor gene locus. Obes Res 1997;5(3):186-192. 44. van Rossum EF, Lamberts SW. Polymorphisms in the glucocorticoid receptor gene and their associations with metabolic parameters and body composition. Recent Prog Horm Res 2004;59:333-357. 45. Binder EB. The role of FKBP5, a co-chaperone of the glucocorticoid receptor in the pathogenesis and therapy of affective and anxiety disorders. Psychoneuroendocrinology 2009;34 Suppl 1:S186-195. 46. Panarelli M, Holloway CD, Fraser R, et al. Glucocorticoid receptor polymorphism, skin vasoconstriction, and other metabolic intermediate phenotypes in normal human subjects. J Clin Endocrinol Metab 1998;83(6):1846-1852. 47. van Rossum EF, Russcher H, Lamberts SW. Genetic polymorphisms and multifactorial diseases: facts and fallacies revealed by the glucocorticoid receptor gene. Trends Endocrinol Metab 2005;16(10):445-450. Figure 1: Comparison of log10 transformed plasma cortisol levels between heterozygous or
non-carriers of the BclI *G polymorphism and homozygous BclI GG carriers. Preoperative cortisol measurements were performed in the morning before surgery and post-operative mea- surements in the morning on the day after surgery. *indicates significantly lower preoperative log10 transformed plasma cortisol concentrations in homozygous patients (p=0.04, t-test). Lower log10 transformed plasma cortisol levels in homozygous carriers correspond to 5.0±0.5 vs. 8.2±1.2 µg/dl in heterozygous/non carriers. Data are mean±SEM. Figure 2: Comparison of changes in the number of standardized traumatic memories from
ICU treatment in cardiac surgical patients across 3 time points of measurements between hete- rozygous or non-carriers of the BclI *G allele and homozygous BclI *G allele carriers Figure 3: Number of traumatic memories from ICU treatment at 6 months after CS in rela-
tionship to the Bc/I *G polymorphism of the GR gene. *p<0.01 when homozygotes were compared to non-carriers of the G-allele. #indicates p<0.05 for the difference in traumatic memories between heterozygotes and homozygotes. Data are mean±SEM. Figure 4: Comparison of changes in PTSD stress-symptom scores following ICU treatment in
cardiac surgical patients across 3 time points of measurements between heterozygous or non- carriers of the BclI *G allele and homozygous BclI *G allele carriers (*p=0.02). Data are Patient and Treatment Variables
BclI*GG carri-
Heterozygotes and non-
P-values
carriers of the BclI*G
tiona [min] Duration of aortic cross-clampinga [min] avalues are mean ±SD bAmerican Society of Anesthesiologists classification of perioperative risk cNew York Heart Association classification of heart failure dCanadian Cardiovascular Society classification of angina pectoris eAcute Physiology and Chronic Health Evaluation score Table 1: Comparison of patient and treatment variables and disease severity at study inclu-
sion between homozygous BclI *G allele carriers and heterozygous or non-carriers of the al-
lele.
BclI GG carriers
Heterozygotes and
non-carriers of the
BclI *G allele
ICU [d] Duration of postoperative mechanical ventilationa [hrs] Duration of epinephrine therapya [d] antagonists [% of patients] Perioperative use of hydrocortisonef [% of patients] Acute heart failurec [% of patients] avalues are mean+SD bpostoperative sedation was performed in the ICU with either midazolam or propofol cAcute heart failure was defined by a significantly reduced cardiac function necessitating the application of positively inotropic drugs (drug of first choice was epinephrine in all patients). dAcute renal failure was defined by a doubling of the preoperative plasma creatinine level or oliguria. eAcute lung injury was defined as a pO2/FiO2 ratio of less than 300 during post-operative mechanical ventilation fthere were no significant differences in the demographic-, short- or long-term outcome variables described in the table when homozygous BclI GG – carriers who had received hydrocortisone (n=6) were compared to homozygous individuals who did not (n=13). Likewise, no differences were found between demographic, treatment and outcome variables when heterozygous/non-carriers with (n=23) and without hydrocortisone use (n=72) were compared (data nor shown). Table 2: Treatment variables and incidence of post-operative organ failures in the homozy-
gote and heterozygote/non-carrier group of the BclI *G allele.

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