The pharmacogenetics of tacrolimus in renal transplant patients: association with tremors, new-onset diabetes and other clinical events.

Our study is the first study to investigate the effect of SNPs in CYP3A5, CYP3A4, ABCB1 and POR genes on the incidence of tremors, nephrotoxicity, and diabetes mellitus. A total of 223 renal transplant patients receiving tacrolimus and mycophenolate mofetil (MMF) were recruited. Both adults and children patients participated in the study. Genotyping was performed using PROFLEX-PCR followed by RFLP. MPA and tacrolimus plasma concentrations were measured by immunoassay. The AUC0-12h of MMF was estimated by a Bayesian method. We found a statistically significant association between the CYP3A5*3 and CYP3A4*1B genotypes and the tacrolimus exposure. We found a lower occurrence of nephrotoxicity (p = 0.03), tremor (p = 0.01), and new-onset diabetes (p = 0.002) associated with CYP3A5*1 allele. The CYP3A4*1B allele was significantly associated with a lower occurrence of new-onset diabetes (p = 0.026). The CYP3A5*1 allele was significantly associated with an increased risk of acute and chronic rejection (p = 0.03 and p < 0.001, respectively). Our results support the usefulness of tacrolimus pharmacokinetics in pre-kidney transplant assessments.

A Population Pharmacokinetic Model to Predict the Individual Starting Dose of Tacrolimus for Tunisian Adults after Renal Transplantation.

BACKGROUND: Tacrolimus is the most frequently used immunosuppressive drug for preventing renal rejection. However, its use is hampered by its narrow therapeutic index and large intra and interpatient variability in pharmacokinetics. The objective of this study was to externally validate a tacrolimus population pharmacokinetic model developed for the Dutch population and adjust the model for the Tunisian population for use in predicting the starting dose requirement after kidney transplantation. METHODS: Data on tacrolimus exposure were obtained from kidney transplant recipients (KTRs) during the first 3 months post-transplantation. External validation of the Dutch model and its adjustment for the Tunisian population was performed using nonlinear mixed-effects modeling. RESULTS: In total, 1901 whole-blood predose tacrolimus concentrations from 196 adult KTRs were analyzed. According to a visual predictive check, the Dutch model underestimated the starting dose for the Tunisian adult population. The effects of age, together with the CYP3A5*3 and CYP3A4*22 genotypes on tacrolimus clearance were significantly different in the Tunisian population than in the Dutch population. Based on a bodyweight-based dosing, only 21.9% of tacrolimus concentrations were within the target range, whereas this was estimated to be 54.0% with the newly developed model-based dosing. After adjustment, the model was successfully validated internally in a Tunisian population. CONCLUSIONS: A starting-dose population pharmacokinetic model of tacrolimus for Tunisian KTRs was developed based on a previously published Dutch model. Using this starting dose could potentially increase the percentage of patients achieving target tacrolimus concentrations after the initial starting dose.

Timing matters: diurnal variation of maximal fat oxidation and substrate oxidation rates in metabolic syndrome-a randomized crossover study.

PURPOSE: The aim of this study was to investigate if diurnal oscillation in maximal fat oxidation (MFO) and substrate oxidation rates during exercise exists in subjects with metabolic syndrome (MetS). METHODS: In a randomized crossover design, 14 MetS patients were assigned to two graded exercise tests conditions performed in the morning (between 7:00 and 9:00 a.m) and in the afternoon (between 4:00 and 5:00 p.m). MFO was defined as the highest absolute value of fat oxidation obtained from the average of last 2-min stages during an indirect calorimetry test. RESULTS: MFO increased by 20.6% from morning to afternoon (p = 0.0002, Cohen's d = 0.52). There was a significant time of day, (p < 0.0001, η2p = 0.76) and intensity effect (p = 0.002, η2p = 0.32) in fat oxidation (Fatox) rates indicating that Fatox was higher in the afternoon than in the morning. CONCLUSION: Our study extends previous findings on the existence of diurnal variation in maximal fat oxidation to MetS patients, highlighting the afternoon as a more favorable time for fat utilization during exercise. These findings have practical implications for optimizing training timing in MetS patients. TRIAL REGISTRATION NUMBER: PACTR202306776991260.

Influence of genetic and non-genetic factors on acenocoumarol maintenance dose requirement in a Tunisian population.

PURPOSE: We aimed to study potential variables involved in interindividual variability to acenocoumarol (AC) response in order to establish a pharmacogenetic algorithm (PA) that includes clinical and genetic factors to predict adequate AC dose to stabilize anticoagulation in a cohort of Tunisian patients. METHODS: Genotyping of the CYP2C9, VKORC1, CYP4F2, and CALU polymorphisms was conducted on 246 patients using PCR-RFLP technique. AC normalized maintenance dose (NMD): ((mean maintenance dose/international normalized ratio (INR)) equilibrium) was calculated. The statistical study was carried out with SPSS V20. RESULTS: A significant correlation was found between age, BMI, and daily AC dose (r = - 0.397; p < 0.001 and r = 0.215; p = 0.001, respectively). The carriers of mutated alleles CYP2C9*2 or CYP2C9*3 or VKORC1 haplotypes (H1 and H7) were associated with AC hyper-sensibility. After adjustment to potential covariates, these patients presented supra-therapeutic INR during treatment period and needed low AC dose (ORs* = 0.28 [0.06-0.60], p = 0.004; ORs* = 0.12 [0.04-0.05], p < 0.001; ORs* = 0.45 [0.24-0.84], p = 0.01; and ORs* = 0.28 [0.06-0.98], p = 0.049, respectively). However, carriers of VKORC1 haplotypes (H3 and H12) or mutated alleles CYP4F2 (rs2108622) or CALU (rs1043550) tend to resist to treatment, hence long period of therapy initiation, and must be treated with high AC dose (ORs* = 2.67 [81.12-5.91], p = 0.013; ORs* = 8.76 [1.07-76.26], p = 0.019; ORs* = 3.12 [1.01-9.63], p = 0.047; and ORs* = 3.96 [1.41-11.09], p = 0.009, respectively). A final multivariate regression model explained 48.1% of the global interindividual variability in AC dose requirement. CONCLUSION: The PA demonstrated that VKORC1 and CYP2C9 polymorphisms contribution was more important than clinical factors. Applying the PA would allow dose adjustment to treat patients in a personalized manner.

Resistin polymorphims, plasma resistin levels and obesity in Tunisian volunteers.

BACKGROUND: Adipose tissue is an important endocrine organ that secretes a number of adipokines, like Resistin (RETN); it's an adipocytes-secreted cytokine and has been proposed as a link between obesity and diabetes. Many resistin gene polymorphisms were described and their implication in obesity was controversial. This study was to investigate the prevalence of single nucleotide polymorphisms (SNPs) in RETN gene 420C/G; 44G/A; 62G/A; 394C/G and 299 G/A and their association with Resistin level and obesity in Tunisian volunteers. METHODS: We recruited 169 nonobese (mean age=42.16-14.26 years; mean body mass index [BMI]=24.51-3.69 kg/m2 ) and 160 obese (mean age=47.86-11.17 years; mean BMI=36-4.78 kg/m2 ). Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism. Anthropometric parameters, lipid levels, Glycemia and insulinemia were measured, BMI was calculated and insulinresistance was evaluated with the homeostasis model assessment insulin resistance (HOMA-IR) and resistin level was measured by ELISA. Statistical analyses were performed by SPSS19.0. RESULTS: After adjustment for confounding parameters; the Odds Ratio (OR) of obesity associated with mutated genotypes at 420C/G compared with normal genotype was as: OR=2.17; 95% CI [1.28-3.68], P=.004. The serum Resistin levels present no significant association with all RETN polymorphisms and it was significantly associated with BMI (P=.047). In our haplotype analysis, one haplotype seems to be protective and one other seems to be the highest risk to obesity. CONCLUSION: The 420 C/G Polymorphism were associated with obesity and Leptin concentration in our population.

Association between ABCB1 polymorphisms and response to first-generation antiepileptic drugs in a Tunisian epileptic population.

PURPOSE: We aimed in this study to investigate the association between the ATP-Binding Cassette sub-family B, member1 (ABCB1) polymorphisms: C1236T (rs1128503), G2677T (rs2032582) and C3435T (rs1045642), and the resistance to antiepileptic drugs (AEDs). MATERIALS AND METHODS: The Polymerase Chain Reaction-Restriction Fragment Length Polymorphism genotyping of ABCB1 polymorphisms was conducted on 153 Tunisian epileptic patients treated with AEDs. RESULTS: Two genetic polymorphisms of the ABCB1 gene seemed to influence the response to AEDs. In fact, the G2677T T and the C3435T T alleles appeared to increase the risk of developing AEDs resistance (ORs* = 3.13; 95%CI = [1.16-8.98]; p = 0.024 and ORs* = 3.10; 95%CI = [1.15-8.37]; p = 0.025), respectively. However, the C1236T T allele did not seemed to influence the response to AEDs (ORs* = 1.14; 95%CI = [0.53-3.88]; p = 0.471). Haplotypic analysis indicated high-degree linkage disequilibrium of ABCB1 polymorphisms. Our results showed a synergic effect, in fact patients with the CTT and TTT haplotypes were more likely to be drug resistant than patients with the CGC haplotype, these associations remained significant even after adjustment for confounding parameters (ORs* = 2.68; 95%CI = [1.11-8.25]; p = 0.033 and ORs* = 3.76; 95%CI = [1.69-21.05]; p = 0.006, respectively). CONCLUSION: The G2677T T and C3435T T alleles as well as the TT, CTT and TTT haplotypes seemed to be significantly associated with drug-resistance epilepsy in our population. Genetic predisposition, involved in this resistance, may contribute to the establishment of a personal optimized therapy for newly diagnosed epileptic patients.

Mutational Analysis of Agxt in Tunisian Population with Primary Hyperoxaluria Type 1.

BACKGROUND: Primary hyperoxaluria type 1 (PH1) is an autosomal recessive metabolic disorder caused by inherited mutations in the AGXT gene encoding liver peroxisomal alanine:glyoxylate aminotransferase (AGT). PH1 is a clinically and genetically heterogeneous disorder. The aim of our study was to analyze and characterize the mutational spectrum of PH1 in Tunisian patients. MATERIALS AND METHODS: Molecular studies of 146 Tunisian patients suspected with PH were performed by PCR/Restriction fragment length polymorphism (RFLP) to detect seven mutations described as the most common. Direct sequencing for the 11 exons was performed in patients in whom any mutation was not identified. RESULTS: The genetic diagnosis of PH1 was confirmed in 62.3% of patients. The first molecular approach based on PCR/restriction enzyme test was positive in 37.6% of patients, whereas the second molecular approach based on whole gene sequencing was successful in 24% of cases. Twelve pathogenic mutations were detected in our cohort. Two mutations were novel, and five were detected for the first time in Tunisians. The three most frequent mutations were p.Ile244Thr, p.Gly190Arg, and c.33dupC, with a frequency of 43.4%, 21.4%, and 13.1%, respectively. CONCLUSION: The two novel mutations detected in our study extend the spectrum of known AGXT gene mutations. The screen for the mutations identified in this study can provide a useful, cost-effective, and first-line investigation in Tunisian PH1 patients.

MDR-1 and CYP3A5 Polymorphisms in Pediatric Idiopathic Nephrotic Syndrome: Impact on Susceptibility and Response to Steroids (Preliminary Results).

BACKGROUND: Oral steroid treatment is the first line of therapy for childhood nephrotic syndrome (NS). However, resistance to this treatment has been observed in some patients. Here, we investigated the association of two steroid metabolism-related genes with susceptibility to childhood NS and the steroid response. METHODS: We genotyped the single nucleotide polymorphisms (SNP) of MDR-1 [C1236T (rs1128503), G2677T/A (rs2032582), and C3435T (rs1045642)] and the CYP3A5 gene (A6986G) in 63 NS patients and 110 age and gender matched controls by PCR-RFLP. RESULTS: Based on multivariate logistic regression analysis carrying the G2677A A allele seemed to multiply both the risk of NS and the risk of developing glucocorticoid (GC) resistance by three-fold (OR = 3.50, [1.37 - 7.06] , p < 0.001, OR = 3.07, [1.06 - 26.10], p = 0.048, respectively). When combined into haplotype, the TAT (1236_T, 2677_A, and 3435_T) haplotype conferred a two-fold NS risk (OR = 2.26, [1.11 - 4.58], p = 0.023) and almost three-fold risk to develop resistance to GC (OR = 2.69, [1.12 - 8.79], p = 0.044). However, TAT carriers seemed to have less risk to develop NS at late age (OR = 0.34, [0.12 - 0.92], p = 0.037). The C1236T (MDR-1) and the A6986G (CYP3A5) polymorphisms showed a trend of association to GC resistance but these associations did not reach the statistical significance (OR = 2.83, [0.54 - 14.67], p = 0.294), (OR = 2.11, [0.53 - 8.38], p = 0.28), respectively. CONCLUSIONS: Here we report that only the G2677A polymorphism was associated to NS susceptibility and steroid resistance. The TAT haplotype was associated with NS susceptibility especially at an early age and with steroid resistance.

Genetic Variation in the Renin-Angiotensin System and Diabetic Nephropathy in the Tunisian Population.

BACKGROUND: The aim of this study was to evaluate the association of ACE, angiotensinogen (AGT) and angiotensin II receptor type I (AGTR1) polymorphisms with diabetic nephropathy (DN) in Tunisians. METHODS: The study population comprised 236 type 2 diabetic patients: with nephropathy (DN = 47) and without nephropathy (DM = 189). Genotyping of ACE-I/D-rs1799752, ACE-rs4343G>A, AGT-rs5050A>C, AGT-rs 4762C>T, AGT-rs699A>G, and AGTR1-rs5186A>C was performed by PCR-RFLP. Haplotype and statistical analysis were realized using SNP Analyzer2.0 and SPSS20, respectively. RESULTS: Genotype frequencies were in Hardy-Weinberg equilibrium. After adjustment for potential confounding factors (age, gender, diabetes duration, hypertension…), an increased risk for DN was associated with mutated alleles of rs4762 (OR = 10.25, p = 0.001), rs699 (OR = 22.21, p < 0.001), and rs5186 (OR = 11.25, p < 0.001). However, mutated alleles of rs1799752 seemed to be protector (OR = 0.41, p = 0.011). Adjusted ORs of DN associated with the ACE haplotype (DA) was (OR = 9.56, p = 0.047) and with the ACE-AGT haplotype (ATADAA) was (OR = 5.38, p = 0.032). CONCLUSIONS: This study indicates that common variants in ACE, AGT, and AGTR1 seem to play a role in genetic susceptibility to DN in Tunisian population and provides evidence for a disease haplotype: ATADAA.

Unusual clinical outcome of primary Hyperoxaluria type 1 in Tunisian patients carrying 33_34InsC mutation.

BACKGROUND: Primary hyperoxaluria type 1 (PH1), is a rare and heterogeneous disease and one of major causes of renal insufficiency in Tunisia, caused by mutations in the AGXT gene. 33-34InsC mutation, was mainly described in children with a severe clinical feature leading to early death, but it was uncommonly reported in adult patients. METHODS: Common mutations in AGXT were tested using PCR/RFLP technique in 111 patients (68 adult, 43 children) with suspected PH1. RESULTS: We described 16 cases (eight adult and eight children) with a 33-34InsC mutation with a median age of 24 years [6 months - 73 years]. All children were in end stage renal disease (ESRD) at the median age of 3 years due to lithiasis and/or nephrocalcinosis. Unfortunately, 75% of them died with a median age of 2.5 years. For the majority of adults only spontaneous elimination of urolithiasis were noted, 37.5% preserved until now a normal renal function and 62.5% of them reached ESRD at the median age of 55.8 ± 12.31 years old. CONCLUSION: In this study 33-34InsC mutation gives a controversial clinical effect in children and adults. The implication of other genetic and/or environmental factors can play a crucial role in determining the ultimate phenotype.

Association of ADIPOQ, leptin, LEPR, and resistin polymorphisms with obesity parameters in Hammam Sousse Sahloul Heart Study.

BACKGROUND: Adipose tissue is an important endocrine organ that secretes a number of adipokines, such as adiponectin (ADIPOQ), leptin (LEP), leptin receptor (LEPR), and resistin (RETN) which may be implicated in obesity. Some adipokines' polymorphisms of genes might influence their concentrations and/or activities. Our aim was to study the relationship between seven SNPs in ADIPOQ (+45T

HOGA1 Gene Mutations of Primary Hyperoxaluria Type 3 in Tunisian Patients.

BACKGROUND: Primary hyperoxaluria type 3 (PH3) is due to mutations in the recently identified 4-hydroxy-2-oxoglutarate aldolase (HOGA1) gene. PH3 might be the least severe form with a milder phenotype with good preservation of kidney function in most patients. The aim of this study was to report three PH3 cases carrying mutations in HOGA1. MATERIALS AND METHODS: Genetic analysis of HOGA1 was performed in patients with a high clinical suspicion of PH after sequencing of AGXT and GRHPR genes, which was negative. Also, a complete AGXT/GRHPR MLPA was performed in these patients in order to detect large deletions/insertions. RESULTS AND DISCUSSION: Two different HOGA1 gene mutations were identified: the p.Pro190Leu in a homozygous state and the p.Gly287Val in two patients in homozygous and heterozygous carriers. The median age at onset of clinical symptoms was 3.93 years. Most of the patients had a positive family history for recurrent urolithiasis. The p.Pro190Leu mutation was reported with impaired renal function at follow-up; however, the p.Gly287Val was presented with normal renal function. All patients were presented with urolithiasis, but only one had a nephrocalcinosis. CONCLUSION: This study expanded the number of PH3 patients from 63 to 66 cases. The p.Pro190Leu and the p.Gly287Val mutations found in this study can provide a first-line investigation in Tunisian PH1 patients.

Association between haptoglobin 2-2 genotype and coronary artery disease and its severity in a tunisian population.

Haptoglobin (Hp) polymorphism generates three common human genotypes (Hp1-1, Hp2-1, and Hp2-2), having functional differences, related to the risk of development of cardiovascular diseases. These functions are a consequence of hemoglobin binding that leads to the synthesis of an antioxidant like ferritin. We explored the association of Hp polymorphism with significant coronary stenosis (SCS) and its severity within 400 Tunisian patients, using genotyping, biochemical parameters, and the Gensini score. After adjustments for age and gender, Hp2-2 was associated with the highest ferritin but the lowest Hp concentrations. After adjustments for confounding parameters, the OR of SCS associated with Hp2-2 was 1.74 (95% CI 1.18-2.58; p = 0.005). This effect was enhanced within diabetics (OR 1.90, 95% CI 1.11-3.24; p = 0.018), obese subjects (OR 1.98, 95% CI 1.10-4.86; p = 0.034), and smokers (OR 4.17, 95% CI 1.54-1.29; p = 0.005). The Hp2-2 genotype is associated with an increase in SCS especially in diabetics, the obese, and smokers.

Designing a Simple Electrochemical Genosensor for the Detection of Urinary PCA3, a Prostate Cancer Biomarker.

This study investigates the feasibility of a simple electrochemical detection of Prostate Cancer Antigen 3 (PCA3) fragments extracted from patients' urine, using a thiolated single-strand DNA probe immobilized on a gold surface without using a redox probe. To enhance the PCA3 recognition process, we conducted a comparative analysis of the hybridization location using two thiolated DNA probes: Probe 1 targets the first 40 bases, while Probe 2 targets the fragment from bases 47 to 86. Hybridization with PCA3 followed, using square wave voltammetry. The limit of detection of the designed genosenors were of the order of (2.2 ng/mL), and (1.6 ng/mL) for Probes 1 and 2, respectively, and the subsequent sensitivities were of the order of (0.09 ± 0.01) µA-1 · µg-1 · mL and (0.10 ± 0.01) µA-1 · µg-1 · mL. Specificity tests were then conducted with the sensor functionalized with Probe 2, as it presents better analytical performances. The electrochemical results indicate that the designed sensor can clearly discriminate a complementary target from a non-complementary one. A further modeling of the calibration curves with the Power Law/Hill model indicates that the dissociation constant increases by one order of magnitude, confirming the ability of the designed sensor to perfectly discriminate complementary targets from non-complementary ones.

Association of PON1 and PON2 polymorphisms with PON1 activity and significant coronary stenosis in a Tunisian population.

PON1 and PON2 have attracted considerable attention as candidate genes for coronary heart disease because their enzymes function as key factors in lipoprotein catabolism pathways. We studied the distribution of PON1 and PON2 polymorphisms, including genotyping, lipid profile, and PON1 activity, and their association with PON1 activity and significant coronary stenosis (SCS) in a Tunisian population. PON1 activity was lower in patients with SCS than in controls. It increased with the R allele (QQ < QR < RR) in PON1-192 genotypes and with the L allele (MM < ML < LL) in PON1-55 genotypes. In the presence of metabolic syndrome and diabetes, PON1-192RR and PON2-311CC were associated with an increased risk of SCS and PON1-55MM seems to have lower risk. This association was evident among nonsmokers for PON1-55MM and among smokers for PON1-192RR and PON2-311CC. The GTGC haplotype seemed to increase the risk of SCS compared with the wild haplotype in a Tunisian population.

Effect of Pre-Meal Metformin With or Without an Acute Exercise Bout on Postprandial Lipemic and Glycemic Responses in Metabolic Syndrome Patients: A Randomized, Open Label, Crossover Study.

INTRODUCTION: Both exercise and pre-meal metformin could lower postprandial glucose and lipid profiles. AIMS: To explore whether pre-meal metformin administration is superior to metformin administration with the meal in reducing postprandial lipid and glucose metabolism, and whether its combination with exercise confer superior benefits in metabolic syndrome patients. MATERIALS AND METHODS: In a randomized crossover design, 15 metabolic syndrome patients were assigned to 6 sequences including 3 experimental conditions: metformin administration with a test meal (met-meal), metformin administration 30 min prior to a test meal (pre-meal-met) with or without an exercise bout designed to expend 700 Kcal at 60% VO2 peak performed the evening just before pre-meal-met condition. Only 13 participants (3 males, 10 females; age: 46 ± 9.86, HbA1c: 6.23 ± 0.36) were included in the final analysis. RESULTS: Postprandial triglyceridemia was unaffected by any condition (all P > .05). However, both pre-meal-met (-7.1%, P = .009) and pre-meal-metx (-8.2%, P = .013) significantly reduced total cholesterol AUC with no significant differences between the two latter condition (P = .616). Similarly, LDL-cholesterol levels were significantly lower during both pre-meal-met (-10.1%, P = .013) and pre-meal-metx (-10.7%, P = .021) compared to met-meal with no difference between latter conditions (P = .822). Plasma glucose AUC was significantly reduced by pre-meal-metx compared to both pre-meal-met (-7.5%, P = .045) and met-meal (-8%, P = .03). Insulin AUC was significantly lower during pre-meal-metx compared to met-meal (-36.4%, P = .044). CONCLUSIONS: Metformin administration 30 minutes prior to meal seems to exert favorable effects on postprandial TC and LDL-Cholesterol levels compared to its administration with meal. Addition of one exercise bout only improved postprandial glycemia and insulinemia. TRIAL REGISTRY: Pan African clinical trial registry, Identifier PACTR202203690920424.

DPYD and TYMS polymorphisms as predictors of 5 fluorouracil toxicity in colorectal cancer patients.

Colorectal cancer (CRC) is the third most common cancer and the fourth leading cause of cancer death. 5-Fluorouracil (5-FU) is an essential component of systemic chemotherapy for CRC. Our objective was to determine the genotypic frequency of polymorphisms affecting dihydropyrimidine dehydrogenase (DPYD) and thymidylate synthetase (TYMS) genes and to correlate the genetic profile with the toxicity due to 5-FU, also considering nongenetic factors. This is a prospective study that involved 66 patients. We extracted DNA by salting out methods. We carried out the genotyping of the different polymorphisms by simple PCR for the TYMS 5'UTR and by PCR-RFLP for DPYD: 1905 + 1 G > A, 85 T > C, 496 A > G, 1679 T > G, c.483 + 18G > A and the TYMS: 5'UTR VNTR, 5'UTR G > C and 3'UTR. The study of the association of DPYD and TYMS polymorphisms with the various signs of toxicity under 5-FU revealed that the polymorphisms 496 A > G were significantly associated with hepatotoxicity: OR = 3.85 (p = 0.04). In addition, 85 T > C was significantly associated with mucositis and neurotoxicity: OR = 4.35 (p = 0.03), OR = 3.79 (p = 0.02). For TYMS, the only significant association we observed for 5'UTR with vomiting: OR = 3.34 (p = 0.04). The incidence of adverse reactions related to 5-FU appears to be influenced in patients with CRC by the identified DPYD and TYMS gene polymorphisms in the Tunisian population.

Variability in response to vitamin D supplementation according to vitamin D metabolism related gene polymorphisms in healthy adults.

OBJECTIVE: The aim of this study was to determine the influence of polymorphisms in some key gene actors of the vitamin D (vitD) metabolic pathway on supplementation efficacy. METHODS: In total, 245 healthy participants were recruited from occupational medicine service in Sahloul University Hospital with vitD deficiency [25(OH)D ≤ 30 ng/ml]. After giving an informed consent, all participants were asked to complete a generalized questionnaire and to follow a detailed personalized supplementation protocol. Genetic study was performed by PCR-RFLP for 15 single nucleotide polymorphisms (SNPs) belonging to DBP, CYP2R1, CYP27B14, CYP24A1 and VDR genes. Statistical study was carried out with SPSS23.0. RESULTS: Among the studied SNPs, non-response was significantly associated with variant alleles of rs4588 (OR* = 11.51; p < 0.001), rs10766197 (OR* = 6.92; p = 0.008) and rs12794714 (OR* = 5.09; p = 0.004). These three SNPs contributed in 18.8% in response variability with rs4588 being the most influential (10.3%). There was a significant linear negative correlation between baseline 25(OH)D and post supplementation 25(OH)D concentration (r = -0.437; p < 0.001) as well as a linear negative association between the increase in 25(OH)D concentration and GRS (GRS: genetic risk score = the sum of risk alleles) (r = -0.149; p = 0.033). CONCLUSIONS: DBP-rs4588, CYP2R1-rs10766197 and rs12794714 variants are associated with variations in serum 25(OH)D concentrations and efficacy of response to vitD supplementation in Tunisian adults. Taking into account these variations can help to better adapt vitD intake to ensure a higher response to supplementation.

Six lipoprotein lipase gene polymorphisms, lipid profile and coronary stenosis in a Tunisian population.

Lipoprotein lipase (LPL) is the rate-limiting enzyme in the hydrolysis of triglyceride-rich lipoprotein particles (Chylomicrons and very-low-density lipoprotein). LPL polymorphisms' effects on lipids and coronary artery disease are controversial among studies and populations. Our aim was to study the association between six polymorphisms, haplotypes and significant coronary stenosis (SCS), disease severity and lipid parameters in Tunisian patients. LPL PvuII, 93 T/G, 188 G/E, HindIII, N291S and D9N polymorphisms were analyzed in 316 patients who underwent coronary angiography. Assessment of coronary angiograms identified SCS as the presence of stenosis >50 % in at least one major coronary artery. The stenosis severity was determined by using Gensini score and vessels number. A significant association of SCS with TT of the HindIII polymorphism was showed (odds ratio (OR): 2.84, 95 % CI, 1.19-7.40, p = 0.017) and TG (OR: 1.77, 95 % CI, 1.99-2.82, p = 0.033). The mutated HindIII genotype was significantly associated with increased TG and ApoB/ApoA-I ratio and with decreased HDL-C. Haplotype analysis showed that OR of SCS associated with the CTGTAG haplotype was 2.12 (95 % CI 1.05-4.25, p = 0.032) and with CGGGAA was 0.71 (95 % CI 0.26-1.95, p = 0.022) compared to the CTGTAA. Significant difference in Gensini score was observed among HindIII genotype and haplotypes. A significant association between the mutated genotype of HindIII polymorphism and decreased HDL-C level and increased ApoB/ApoA-I ratio and TG level was showed. Our results suggest that HindIII and D9N polymorphisms and CTGTAG haplotype seem to be considered as marker of predisposition to coronary stenosis. In another hand, HindIII and haplotypes were related to stenosis severity.

Effect of cigarette smoking on paraoxonase 1 activity according to PON1 L55M and PON1 Q192R gene polymorphisms.

OBJECTIVE: This study aims to investigate the effect of cigarette smoking on paraoxonase 1 (PON1) activity according to PON1 L55M and PON1 Q192R gene polymorphisms. MATERIALS AND METHODS: Our sample included 300 voluntary subjects: 138 nonsmokers and 162 current smokers aged 38.47 ± 21.91 and 35.55 ± 16.03 years, respectively. PON1 activity was determined by kinetic methods. L55M and Q192R gene polymorphisms of PON1 were determined by multiplex polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). RESULTS: We found in smokers a significant decrease of PON1 activity before and after adjustment. We noted a significant association between smoking status and lower PON1 activity [odds ratio (OR) = 3.03, confidence interval 95% = 1.5-5.9, p = 0.001]. In smokers, there was significant association between PON1 activity and PON1 L55M polymorphisms (p = 0.01). Also, the 55MM genotype presented the lowest paraoxonase activity, while the 55LL genotype showed the highest one. After adjustment for confounding variables, smokers with PON1 L55M polymorphism had the highest risk for lower PON1 activity; however, PON1 Q192R genotype might protect smokers from decrease in PON1 activity. We found significant interaction between the effect of cigarette smoking and both PON1 L55M and PON1 Q192R polymorphisms on lower PON1 activity. CONCLUSIONS: Cigarette smoking was significantly associated with decrease in PON1 activity. Moreover, PON1 L55M polymorphism predisposes smokers to decreased PON1 activity in contrast to PON1 Q192R genotype.