Human Genetic Variability Contributes to Postoperative Morphine Consumption.

UNLABELLED: High interindividual variability in postoperative opioid consumption is related to genetic and environmental factors. We tested the association between morphine consumption, postoperative pain, and single nucleotide polymorphisms (SNPs) within opioid receptor µ 1 (OPRM1), catechol-O-methyltransferase (COMT), uridine diphosphate glucose-glucuronosyltransferase-2B7, and estrogen receptor (ESR1) gene loci to elucidate genetic prediction of opioid consumption. We analyzed 20 SNPs in 201 unrelated Caucasian patients who underwent abdominal surgery and who were receiving postoperative patient-controlled analgesia-administered morphine. Morphine consumption and pain intensity were dependent variables; age and sex were covariates. A haplotype of 7 SNPs in OPRM1 showed significant additive effects on opioid consumption (P = .007); a linear regression model including age and 9 SNPs in ESR1, OPRM1, and COMT explained the highest proportion of variance of morphine consumption (10.7%; P = .001). The minimal model including 3 SNPs in ESR1, OPRM1, and COMT explained 5% of variance (P = .007). We found a significant interaction between rs4680 in COMT and rs4986936 in ESR1 (P = .007) on opioid consumption. SNPs rs677830 and rs540825 of OPRM1 and rs9340799 of ESR1 were nominally associated with pain Numeric Rating Scale scores. Combinations of genetic variants within OPRM1, COMT, and ESR1 better explain variability in morphine consumption than single genetic variants. Our results contribute to the development of genetic markers and statistical models for future diagnostic tools for opioid consumption/efficacy. PERSPECTIVE: This article presents the efforts dedicated to detect correlations between the genetic polymorphisms and the clinical morphine effect self-administered by patients using a patient-controlled analgesia pump after major surgery. The clinical effect is expressed in terms of morphine consumption and pain scores. REGISTERED ON CLINICALTRIALS.GOV: NCT01233752.

Soluble HLA-G in pregnancies complicated by autoimmune rheumatic diseases.

Autoimmune rheumatic diseases in pregnancies are associated with increased adverse obstetric outcomes. We compared maternal soluble human leucocyte antigen-G (sHLA-G) blood levels in subjects with a rheumatic disease preexisting pregnancy and unaffected controls. Third-trimester blood maternal sHLA-G concentrations were significantly higher in subjects with rheumatic diseases than in controls (mean 93.1ng/ml [SD 42.1] vs 58.1ng/ml [SD 96.3], p=0.003). Cord blood sHLA-G concentrations were significantly higher in rheumatic disease than in those born to control mothers (median 41.2ng/ml [IQR: 3.3-44.0] vs 17.9ng/ml [IQR: 17.2-88.1], p=0.007). A strict positive correlation (r=0.88, p<0.001) was found between the maternal and fetal titers of ANA autoantibodies as well as between maternal and fetal sHLAG circulating levels (r=0.58 and r=0.67, respectively, for controls and cases, p<0.001). Maternal s-HLA-G blood concentrations were significantly higher in subjects with rheumatic disease DEL/DEL homozygous for a polymorphism of the 3' untranslated regulatory region of HLA-G (HLA-G 14bp) than in the corresponding healthy controls (mean values 141.5ng/ml [SD: 166] vs 54.2ng/ml [SD: 35], p=0.009). Increasing maternal and cord blood levels of s-HLA-G concentrations among pregnant subjects with rheumatic diseases compared with controls suggest that autoimmune diseases prompt a maternal and fetal immune response that favors pregnancy immune tolerance.

Temporal variation in soluble human leukocyte antigen-G (sHLA-G) and pregnancy-associated plasma protein A (PAPP-A) in pregnancies complicated by gestational diabetes mellitus and in controls.

PROBLEM: To target gestational diabetes mellitus (GDM) by means of temporal variation in pregnancy-associated plasma protein A (PAPP-A) and soluble human leukocyte antigen-G (sHLA-G). METHOD OF STUDY: Retrospective analysis of PAPP-A and sHLA-G blood levels in historical samples of 112 GDM and 112 controls, drawn at first trimester, and prospective study in 18 GDM and 105 controls collected in triplicate along the pregnancy. Six hundred and sixty-five samples were analyzed. RESULTS: Gestational diabetes mellitus had significantly lower first-trimester PAPP-A concentrations than controls (2343±1519 versus 2996±1955 mU/mL, in retrospective brunch and 2490.57±1828.52 versus 3240.84±1930.69 mU/L in prospective one, P<0.001). First-trimester sHLA-G level was significantly lower in GDM than in controls (52.88±59.69 versus 66.81±50.14 ng/mL, P<0.001) and increased during gestation in diabetic women showing an opposite trend with respect to the controls. CONCLUSION: PAPP-A and sHLA-G are independent markers of GDM. Quantitative variations during pregnancy help to early unravel the onset of GDM.

Genetic variability at COMT but not at OPRM1 and UGT2B7 loci modulates morphine analgesic response in acute postoperative pain.

PURPOSE: To investigate interindividual variability in response to pain treatment, we characterized postoperative patients for morphine metabolism and for COMT, OPRM1 and UGT2B7 polymorphisms. METHODS: A total of 109 patients treated with morphine were genotyped by DNA sequencing for 12 DNA polymorphisms of the COMT, OPRM1 and UGT2B7 genes. The plasma concentration of morphine and of M3G/M6G metabolites were evaluated by means of reversed phase high-performance liquid chromatography coupled with mass spectrometry. RESULTS: An association between average morphine consumption during the first 24 postoperative hours by patient-controlled analgesia (PCA) and COMT haplotypes was found. Specifically, patients with the diplotype for average pain intensity (APS/APS) required the lowest morphine doses compared to the other subjects (p = 0.011). The APS haplotype contains an adenine corresponding to methionine, instead of valine, at position 158 of the COMT protein. Met/Met homozygous patients consumed significantly lower morphine doses than other subjects (p = 0.014); accordingly, Val158Met genotyping alone might be used in the clinical setting to predict PCA morphine need. Considering both COMT Val158Met and OPRM1 A118G polymorphisms, carriers of both the Met/Met and AA genotypes required less morphine than other subjects, although the difference was not significant. The analysis of UGT2B7 revealed the occurrence of two common haplotypes (G_C_C_A_C and A_T_T_G_T) that did not prove to be related with plasma morphine and M3G/M6G concentration. CONCLUSIONS: By considering COMT, OPRM1, and UGT2B7 genotypes, as well as pharmacokinetic results, only COMT polymorphisms appear to be predictive of morphine need in postoperative pain therapy.

Influence of COMT Val158Met polymorphism on Alzheimer's disease and mild cognitive impairment in Italian patients.

COMT (Catechol-O methyltransferase) gene is one of the key players in synaptic plasticity and in learning and memory mechanisms. A single nucleotide polymorphism (rs4680; G to A) in the COMT coding region causes Val158Met aminoacid substitution in the corresponding protein, with Val allele exhibiting a 3- to 4-fold increase in enzyme activity compared to Met. With the purpose of examining the influence of COMT as a genetic risk factor for cognitive impairment, we analyzed a sample of 248 healthy subjects, 276 patients affected by Alzheimer's disease (AD), and 70 subjects with mild cognitive impairment (MCI), the latter condition possibly representing a prodrome for dementia. All subjects were analyzed for COMT rs4680 polymorphism and APOE genotype. Our study strengthens data showing that APOE ε4 allele is an independent risk factor for AD and also a risk factor for MCI. Neither COMT alleles nor genotypes proved to be independently associated with the risk of AD or MCI in our sample. However, we found an association between COMT GG genotype (Val/Val) and APOE ε4 carrier status and the risk of AD and MCI. In particular, when GG genotype is included into the multinomial analysis, the risk of AD and MCI due to APOE ε4 allele is increased of about 2-3 fold; moreover, the risk conferred by the combination of G and ε4 alleles is more pronounced in male patients. To our knowledge, this synergistic effect is here shown for the first time on a population sample representative of Caucasian patients.

How and why to screen for CYP2D6 interindividual variability in patients under pharmacological treatments.

Cytochromes P450 are members of a superfamily of hemoproteins that catalyze a variety of oxidative reactions in the metabolism of endogenous and exogenous hydrophobic substrates. Fifty-eight cytochrome P450 (CYP) isoenzymes belonging to 18 families have been identified in human cells; the corresponding genes are highly polymorphic, and genetic variability underlies interindividual differences in drug response. The polymorphisms of CYP2D6 significantly affect the pharmacokinetics of about 50% of the drugs in clinical use, which are CYP2D6 substrates. The number of functional CYP2D6 alleles per genome determines the existence of four different phenotypes, i.e. poor, intermediate, extensive, and ultrarapid metabolizers. CYP2D6 genetic variants include copy number variations, single nucleotide substitutions, frameshift and insertion/deletion mutations. This review reports some of the different methodological approaches used to screen for CYP2D6 variants and focuses on methods that have improved variation detection, from conventional techniques to more recent microarray technology and high throughput DNA sequencing. In addition, this review reports some results on clinical relevance of CYP2D6 polymorphisms and provides examples of variability in drug response associated with interindividual phenotypic differences.