Lessons from prospective longitudinal follow-up of a French APECED cohort

BACKGROUND

APECED syndrome is a rare disease caused by biallelic mutations of the AIRE gene, usually presenting with the triad "hypoparathyroidism-adrenal failure-chronic mucocutaneous candidiasis (CMC)" and non-endocrine manifestations. The aim of this study was to determine the molecular profile of the AIRE gene, the prevalence of rare manifestations and to characterize immunological disturbances in a French cohort.

PATIENTS AND METHODS

A national, multicenter prospective observational study to collect genetic, clinical, biological and immunological data (NCT03751683).

RESULTS

25 patients (23 families) were enrolled. Eleven distinct AIRE variants were identified, two of which were not previously reported: an intronic variant, c.653-70G > A, and a c.1066del (p.Arg356GlyfsX22) variant (exon 9). The most common was the Finnish variant c.769C > T (16 alleles), followed by the variant c.967_979del13 (15 alleles), which seemed associated with a less severe phenotype. 17/25 patients were homozygote. The median number of clinical manifestations was seven; 19/25 patients presented with the hypoparathyroidism-adrenal failure-CMC triad, 8/13 showed pulmonary involvement, 20/25 had ectodermal dystrophy, 8/25 had malabsorption, and 6/23 had asplenia. Fifteen out of 19 patients had NK cell lymphopenia with an increase in CD4+ and CD8+ T lymphocytes and an age-dependent alteration of B lymphocyte homeostasis compared with matched controls (p < 0.001), related to the severity of the disease. All tested sera (n = 18) were positive for anti-interferon-α, 15/18 for anti-interleukin-22 antibodies, and 13/18 for anti-interleukin-17F antibodies, without clear phenotypic correlation other than with CMC.

CONCLUSION

This first prospective cohort showed a high AIRE genotype variability, with two new gene variants. The prevalence of potentially life-threatening non-endocrine manifestations, was higher with systematic screening. These manifestations could, along with age-dependent B-cell lymphopenia, contribute to disease severity. Systematic screening for all the manifestations of the syndrome would allow earlier diagnosis, supporting vaccination, and targeted therapeutic approaches.

Comparison of biomarker for diagnosis of nitrous oxide abuse: challenge of cobalamin metabolic parameters, a retrospective study

BACKGROUND

Recreational use of nitrous oxide (N₂O) leads to neurological disorders including combined subacute degeneration of spinal cord, psychological disorders, and thrombosis. Serum or urine N₂O assays could not be routinely performed. Hence, it is necessary to investigate other biological markers such as metabolic markers. We aimed here to challenge the three main biological markers used for the diagnosis of nitrous oxide abuse as total vitamin B12, homocysteine, and methylmalonic acid.

METHODS

We retrospectively collected clinical and biological data from 52 patients with known, documented chronic N₂O abuse and associated clinical signs (peripheral neuropathy disability score or thrombosis event). Sera and plasma total vitamin B12, methylmalonic acid (MMA), and homocysteine were performed to identify the most specific marker of chronic N₂O intoxication and related clinical outcomes.

RESULTS

Plasma homocysteine was almost consistently increased in case of N₂O chronic consumption, whereas MMA increase and total vitamin B12 decrease are not systematically found. Our results showed that none of the markers are correlated with levels of N₂O consumptions. However, homocysteine and MMA are correlated with clinical severity, but MMA seems to be a better marker of clinical severity.

CONCLUSION

There is no specific marker of nitrous oxide abuse according to levels of consumption, total vitamin B12 decrease could not be used either as consumption or as severity marker. However, we showed that homocysteine is consistently increased and could be used as marker of recent N₂O consumption. On the other hand, we showed that MMA could be used as a marker of clinical gravity.

Feasibility, safety and effectiveness of a pilot 16-week home-based, impact exercise intervention in postmenopausal women with low bone mineral density

The feasibility and efficacy of home-based, impact exercise are unclear. This pilot impact exercise intervention was feasible and safe, and improved bone health and physical function in postmenopausal women with low bone density. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk.

INTRODUCTION

The feasibility and efficacy of impact exercise in postmenopausal women with low bone mineral density (BMD) are unclear. We aimed to determine adherence, safety and changes in BMD, bone microarchitecture and physical function following a pilot home-based, impact exercise intervention in postmenopausal women with low BMD.

METHODS

Fifty community-dwelling postmenopausal women with BMD T-scores < - 1.0 participated in 16 weeks of home-based impact exercise progressively increasing to 50 multi-directional unilateral hops on each leg daily. Bone density and structure were assessed by lumbar spine and hip dual-energy X-ray absorptiometry (DXA), 3D modelling (3D-SHAPER) of hip DXA scans and distal tibial high-resolution peripheral quantitative computed tomography scans. Physical performance was assessed by repeated chair stand time and stair climb time.

RESULTS

Forty-four women (mean ± SD age 64.5 ± 7.5 years) completed the intervention, with adherence of 85.3 ± 17.3%. Reasons for withdrawal were related soreness (n = 2), unrelated injury (n = 1) and loss of interest (n = 3). Femoral neck areal BMD increased by 1.13 ± 3.76% (p = 0.048). Trabecular volumetric BMD (vBMD) increased at the total hip (2.27 ± 7.03%; p = 0.038) and femoral neck increased (3.20 ± 5.39%; p < 0.001). Distal tibia total vBMD increased by 0.32 ± 0.88% (p = 0.032) and cortical cross-sectional area increased by 0.55 ± 1.54% (p = 0.034). Chair stand and stair climb time improved by 2.34 ± 1.88 s (p < 0.001) and 0.27 ± 0.49 s (p < 0.001), respectively.

CONCLUSION

A 16-week home-based, impact exercise was feasible and may be effective in improving femoral neck areal BMD, total hip and distal tibial vBMD and physical function in postmenopausal women. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk in older populations.

Differential effects of abaloparatide and teriparatide on hip cortical volumetric BMD by DXA-based 3D modeling

In postmenopausal osteoporotic women in ACTIVE, abaloparatide reduced fracture risk and increased areal bone mineral density (BMD) more than teriparatide at the hip and wrist. DXA-based 3D modeling showed significantly greater increases in hip cortical volumetric BMD with abaloparatide versus teriparatide. This may explain differences reported in aBMD by DXA.

INTRODUCTION

In ACTIVE, abaloparatide (ABL) increased bone mineral density (BMD) shown by dual-energy X-ray absorptiometry (DXA) while reducing fracture incidence in postmenopausal osteoporotic women. Changes in DXA BMD with ABL, 80 μg, were significantly greater than with open-label teriparatide (TPTD), 20 μg, at cortical sites including total hip, femoral neck, and 1/3 distal radius. The purpose of this study was to better understand the relative effects of ABL and TPTD on cortical and cancellous compartments in the proximal femur.

METHODS

Hip DXA images from a subset of randomly selected patients in the ACTIVE trial (n = 250/arm) were retrospectively analyzed using three-dimensional modeling methods (3D-SHAPER software) to evaluate changes from baseline at months 6 and 18.

RESULTS

Similar significant increases in trabecular volumetric BMD (vBMD, + 9%) and cortical thickness (+ 1.5%) were observed with ABL and TPTD by 3D-DXA at 18 months. In contrast, only ABL significantly increased cortical vBMD versus baseline (+ 1.3%), and changes in both cortical vBMD and cortical surface BMD were significantly greater with ABL versus TPTD. In the TPTD group, changes in cortical vBMD were inversely correlated with changes in serum CTX (carboxy-terminal telopeptide of type I collagen) and PINP (procollagen type I N-terminal propeptide), suggesting that higher bone turnover may have attenuated cortical gains.

CONCLUSION

These results suggest previously reported differences in areal BMD increases between ABL and TPTD may be due to differential effects on cortical vBMD. Further studies are warranted to investigate how these differences affect therapeutic impact on hip strength in postmenopausal women with osteoporosis.

SUN-598 Phenotypic Study of Meso-Somatous (Roch-Leri) Lipomatosis

Background: Lipomatosis is a condition in which multiple lipomas are present on the body. Different entities which are accompanied by multiple lipomas include Proteus syndrome, Cowden syndrome and related disorders due to PTEN gene mutations, MEN1, benign symmetric lipomatosis (Madelung or Launois-Bensaude disease), Dercum’s Disease, familial lipodystrophy, hibernomas, epidural lipomatosis, familial angiolipomatosis, and meso-somatous lipomatosis (LMS) still called Roch-Leri lipomatosis. LMS is characterized by the presence of many discrete, encapsulated lipomas of 2 to 5 cm, painless, at the level of the trunk and forearms. The aim of the present study was to determine the clinico-biological phenotype of LMS, as compared to controls. Patients and methods: In this single-center study (NCT01784289), 18 healthy controls (C) and 11 LMS were included after examining the cohort of 76 patients referred for suspected lipodystrophic syndrome between 2009 and 2019 in the Endocrinology Department of a University Hospital. Clinical (sex, age, weight, BMI, blood pressure (BP), alcohol consumption), metabolic (fasting blood glucose (FBG) and insulin levels, lipid balance, ASAT, ALAT, GammaGT, leptin), immuno-inflammatory (CBC, lymphocyte immunophenotyping), and anthropometric (% of body fat in DEXA, steatosis and intra-abdominal / total abdominal fat ratio (IAF / TAF) in MRI) were evaluated. Results: The following parameters, expressed as % or median, differed significantly between LMS vs. C groups, respectively: weight 100 vs. 69kg (p<0.01), BMI 30.8 vs. 22.7 (p<0.01), systolic BP 140 vs. 115 (p<0.01) and diastolic BP 80 vs. 70 mmHg (p<0.05), gammaGT 74 vs. 18 IU / L (p<0.01), fasting insulin levels 7.3 vs. 4.7 microIU / mL (p<0.05), leptin 28 vs. 5 ng / mL (p<0.01), CD3 (867 vs. 1444 / mm3 (p<0.01), CD4 499 vs 866 / mm3 (p<0.05), CD8 227 vs. 546 (p<0.05), fat mass 41 vs. 22 (p<0.05). Three LMS patients had hepatic steatosis and 3 a first-degree family member with LMS. Percentage of men (63% vs. 52%, FBG, lipid levels, ASAT, ALT, CBC, IAF / TAF (0.25 vs 0.19) did not differ significantly. The number of lipomas was > 5 in 82% of LMS patients and lipomas were localized first to the forearms (82%), then the thighs (73%) and the abdomen (55%). At diagnosis, the age of LMS patients was 20 years old; 55% of the LMS patients had a BMI above 30 and 45% above 25. No patient had excessive alcohol consumption. Five had a history of auto-immuneor inflammatory disease: 1 hyperthyroidism, 1 hypothyroidism, 1 multiple sclerosis, 1 vitiligo, 1 Raynaud syndrome. Conclusion: LMS mainly affects overweight men and is associated with hypertension, hyperinsulinism, increased gammaGT and a decrease in CD3, CD4 and CD8 lymphocytes, suggesting an immune dysregulation, all the more so that 45% had an associated auto-immune/inflammatory disease.

Associations between physical activity and bone structure in older adults: does the use of self-reported versus objective assessments of physical activity influence the relationship?

Associations of current and previous physical activity (PA) with bone health are unclear. In postmenopausal women with low bone mineral density (BMD), current PA was positively associated with femoral neck BMD and microarchitecture. Past PA was positively associated with tibial microarchitecture. PA appears beneficial for bone health throughout the lifespan.

INTRODUCTION

To compare associations of current and past self-reported bone-specific physical activity, and current accelerometer-determined physical activity (PA), with bone structure (bone mineral density [BMD] and microarchitecture) in postmenopausal women with osteopenia or osteoporosis.

METHODS

Fifty community-dwelling postmenopausal women (mean age 64.4 ± 7.7) with hip or spine BMD T-score < - 1.0 SD were recruited for an exercise intervention. At baseline, current, past and total Bone-specific Physical Questionnaire (BPAQ) scores were self-reported, and percentages of sedentary, light and moderate to vigorous PA (MVPA) were objectively determined by accelerometer measurements. Bone structure was assessed by lumbar spine and hip dual-energy X-ray absorptiometry (DXA), 3D modelling algorithms (3D-SHAPER) of hip DXA scans and distal tibial high-resolution peripheral quantitative computed tomography (HR-pQCT) scans.

RESULTS

Current BPAQ scores and MVPA were significantly positively associated with femoral neck areal BMD (β = 0.315, p = 0.031 and β = 0.311, p = 0.042, respectively) following multivariable adjustments. MVPA was also positively associated with femoral cortical surface BMD (β = 0.333, p = 0.028) and mean cortical thickness (β = 0.374, p = 0.013). Past and total BPAQ scores demonstrated positive associations with tibial trabecular number (β = 0.391, p = 0.008 and β = 0.381, p = 0.010, respectively), and negative associations with trabecular separation (β = - 0.396, p = 0.006 and β = - 0.380, p = 0.009, respectively) and distribution (β = - 0.411, p = 0.004 and β = - 0.396, p = 0.006, respectively). Current BPAQ score was positively associated with tibial cortical periosteal perimeter (β = 0.278, p = 0.014).

CONCLUSION

BPAQ scores were most consistently associated with tibial bone parameters in older women, with past PA having lasting benefits for trabecular microarchitecture, and current PA positively associated with cortical bone.

Discrimination of osteoporosis-related vertebral fractures by DXA-derived 3D measurements: a retrospective case-control study

A retrospective case-control study assessing the association of DXA-derived 3D measurements with osteoporosis-related vertebral fractures was performed. Trabecular volumetric bone mineral density was the measurement that best discriminates between fracture and control groups.

INTRODUCTION

The aim of the present study was to evaluate the association of DXA-derived 3D measurements at the lumbar spine with osteoporosis-related vertebral fractures.

METHODS

We retrospectively analyzed a database of 74 postmenopausal women: 37 subjects with incident vertebral fractures and 37 age-matched controls without any type of fracture. DXA scans at the lumbar spine were acquired at baseline (i.e., before the fracture event for subjects in the fracture group), and areal bone mineral density (aBMD) was measured. DXA-derived 3D measurements, such as volumetric BMD (vBMD), were assessed using a DXA-based 3D modeling software (3D-SHAPER). vBMD was computed at the trabecular, cortical, and integral bone. Cortical thickness and cortical surface BMD were also measured. Differences in DXA-derived measurements between fracture and control groups were evaluated using unpaired t test. Odds ratio (OR) and area under the receiver operating curve (AUC) were also computed. Subgroup analyses according to fractured vertebra were performed.

RESULTS

aBMD of fracture group was 9.3% lower compared with control group (p < 0.01); a higher difference was found for trabecular vBMD in the vertebral body (- 16.1%, p < 0.001). Trabecular vBMD was the measurement that best discriminates between fracture and control groups, with an AUC of 0.733, against 0.682 for aBMD. Overall, similar findings were observed within the subgroup analyses. The L1 vertebral fractures subgroup had the highest AUC at trabecular vBMD (0.827), against aBMD (0.758).

CONCLUSION

This study showed the ability of cortical and trabecular measurements from DXA-derived 3D models to discriminate between fracture and control groups. Large cohorts need to be analyzed to determine if these measurements could improve fracture risk prediction in clinical practice.

SUN-040 Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy (APECED) Syndrome: Prospective Screening of Asplenism and Pneumonitis in a Cohort of 25 Patients

Background: APECED syndrome is a rare monogenic disease caused by homozygous mutation of AIRE gene. It classically presents with chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal insufficiency with an early onset in childhood. Non-endocrine manifestations as ectodermic dystrophy, asplenism and pneumonitis are also observed but their incidence remains unknown and their mechanisms not well understood. APECED has been poorly reported in France although it is widely described in several European countries. The aim of this study was to report on rare manifestations of APECED syndrome in a French cohort. Patients and methods: We performed a multicentric prospective observational study in France in order to collect clinical, biological, immunological and genetic data, after written informed consent in the frame of a PHRC (Hospital Project of Clinical Research #1927). Bronchiolitis, splenic atrophy and ocular manifestations were systematically investigated. Results We enrolled 25 patients between 2009 and 2016. Clinically, the median age at diagnosis was 12 while the median age of the first manifestation was 6, so there was diagnostic delay. The median number of manifestations was seven. 76 % of patients presented with the classical triad. Reduction of lung function was observed in 62% of patients, asplenism in 26%, and ocular manifestation in 33%. Genetically, eleven mutations of the AIRE gene were identified, two of which never previously reported: an intronic variation c.653-70G>A (intron 5) in a patient with hypoparathyroidism as unique manifestation , and c.1066del (p.Arg356GlyfsX22) (exon 9) in a patient from Guadeloupe with composite heterozygous mutations (c.967_979del13; exon 8). The most common AIRE mutation was the mutation R257X. Median age was 26 and sex ratio was 1.1. Biologically, 100% of tested sera were positive for anti-IFNα-antibodies, 15/18 for anti-IL-22, and 13/18 for anti-IL-17F antibodies. Conclusion: This series shows a high genotypic and phenotypic variability of APECED in France, that could be explained by different ethnic origins. The systematic screening for non-classic manifestations shows a more frequent occurrence than in other series. Systematic screening of asplenism and bronchiolitis could be a useful strategy to make an earlier diagnosis, to prevent infections by vaccination and to treat earlier pulmonary involvement. Lastly, antibodies against Th17 cytokines appear as good soluble markers for diagnosis of non-classical presentation of the syndrome.

Chronic Mucocutaneous Candidiasis in Autoimmune Polyendocrine Syndrome Type 1

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is an autosomal recessive disease caused by mutations in the autoimmune regulator (AIRE) gene, characterized by the clinical triad of chronic mucocutaneous candidiasis (CMC), hypoparathyroidism, and adrenal insufficiency. CMC can be complicated by systemic candidiasis or oral squamous cell carcinoma (SCC), and may lead to death. The role of chronic Candida infection in the etiopathogenesis of oral SCC is unclear. Long-term use of fluconazole has led to the emergence of Candida albicans strains with decreased susceptibility to azoles. CMC is associated with an impaired Th17 cell response; however, it remains unclear whether decreased serum IL-17 and IL-22 levels are related to a defect in cytokine production or to neutralizing autoantibodies resulting from mutations in the AIRE gene.

Effects of osteoporosis drug treatments on cortical and trabecular bone in the femur using DXA-based 3D modeling

Effects of osteoporosis drugs on proximal femur cortical and trabecular bone were studied using dual-energy x-ray absorptiometry (DXA)-based 3D modeling method. Changes observed in this head-to-head study were consistent with those obtained using computed tomography in the literature.

INTRODUCTION

The aim of the present study was to assess the effects of osteoporosis drugs on cortical and trabecular bone at the proximal femur using DXA-based 3D modeling.

METHODS

We retrospectively analyzed 155 patients stratified by treatments: naive of treatment (NAIVE), alendronate (AL), denosumab (DMAB), and teriparatide (TPTD). DXA scans were performed at baseline and after treatment, and areal bone mineral density at spine and femur were measured. A software algorithm (3D-SHAPER) was used to derive 3D models from hip DXA scans and compute: trabecular and cortical volumetric BMD (vBMD), cortical thickness (Cth), and cortical surface BMD (cortical sBMD). Changes from baseline were normalized at 24 months and evaluated in terms or percentage.

RESULTS

After 24 months, a non-significant decrease was observed for trabecular vBMD, Cortical sBMD, Cth, and cortical vBMD (- 2.3, - 0.8, - 0.3, and - 0.5%) in the NAIVE group. Under AL and DMAB, significant increases were observed in trabecular vBMD (3.8 and 7.3%), cortical vBMD (1.4 and 2.0%), and cortical sBMD (1.5 and 3.6%). An increase in Cth was observed in patients under DMAB (1.8%). Under TPTD, a significant increase in Trabecular vBMD was observed (5.9%) associated with a non-significant increase of Cth (+ 1%) concomitant with a decrease in cortical vBMD (- 1.1%).

CONCLUSION

Results obtained in this head-to-head study are consistent with those obtained using computed tomography in the literature. DXA-based modeling techniques could complement standard DXA examination to monitor treatment effects on trabecular and cortical compartments.

Analysis of the evolution of cortical and trabecular bone compartments in the proximal femur after spinal cord injury by 3D-DXA

Marked trabecular and cortical bone loss was observed at the proximal femur short-term after spinal cord injury (SCI). 3D-DXA provided measurement of vBMD evolution at both femoral compartments and cortical thinning, thereby suggesting that this technique could be useful for bone analysis in these patients.

INTRODUCTION

SCI is associated with a marked increase in bone loss and risk of osteoporosis development short-term after injury. 3D-DXA is a new imaging analysis technique providing 3D analysis of the cortical and trabecular bone from DXA scans. The aim of this study was to assess the evolution of trabecular macrostructure and cortical bone using 3D-DXA in patients with recent SCI followed over 12 months.

METHODS

Sixteen males with recent SCI (< 3 months since injury) and without antiosteoporotic treatment were included. Clinical assessment, bone mineral density (BMD) measurements by DXA, and 3D-DXA evaluation at proximal femur (analyzing the integral, trabecular and cortical volumetric BMD [vBMD] and cortical thickness) were performed at baseline and at 6 and 12 months of follow-up.

RESULTS

vBMD significantly decreased at integral, trabecular, and cortical compartments at 6 months (- 8.8, - 11.6, and - 2.4%), with a further decrease at 12 months, resulting in an overall decrease of - 16.6, - 21.9, and - 5.0%, respectively. Cortical thickness also decreased at 6 and 12 months (- 8.0 and - 11.4%), with the maximal decrease being observed during the first 6 months. The mean BMD losses by DXA at femoral neck and total femur were - 17.7 and - 21.1%, at 12 months, respectively.

CONCLUSIONS

Marked trabecular and cortical bone loss was observed at the proximal femur short-term after SCI. 3D-DXA measured vBMD evolution at both femoral compartments and cortical thinning, providing better knowledge of their differential contributory role to bone strength and probably of the effect of therapy in these patients.

The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease

Background

Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD.

Aim

The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone.

Methods

Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry.

Results

The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD.

Conclusions

Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.

Influence of Acetaminophen Consumption on Perceived Exertion at the Lactate Concentration Threshold

The purpose of this investigation was to study effects of acetaminophen consumption on ratings of perceived exertion and estimated time limit responses at the lactate threshold. 98 young regional to national level athletes performed a graded exhausting exercise on an outdoor running track to estimate their maximal aerobic velocity and the velocity associated with their lactate concentration threshold. Urine (30 mL) was collected during this test and analysed for numerous substances. During urinary screening for doping substances, 9 acetaminophen consumers (9.2%) among the 98 included athletes were detected. These acetaminophen consumers have significantly lower perceived exertion at velocity corresponding to the lactate concentration threshold than nonconsumers (11.9 ± 2.1 vs 13.6 ± 2.1, respectively) although they were at the same relative exercise intensity. This result shows that acetaminophen consumption may have mediated the perceived exertion response at the lactate concentration threshold. This may then suggest that the pain induced by training load could be a factor in use of self-prescribed pain relievers. Such consumption must be taken into account by medical staff, trainers, or educators who have to give information on the use and adverse effects of this substance and to propose palliative methods to their athletes.

Prevention of isoniazid toxicity by NAT2 genotyping in Senegalese tuberculosis patients

Isoniazid (INH), recommended by WHO (World Health Organization) in the treatment of tuberculosis (TB), is metabolized primarily by the genetically polymorphic N-acetyltransferase 2 (NAT2) enzyme. The human population is divided into three different phenotypic groups according to acetylation rate: slow, intermediate, and fast acetylators. The objective of this study was to explore the relationship between NAT2 genotypes and the serum concentrations of INH. Blood samples from 96 patients with TB were taken for the analysis. NAT2 polymorphisms on coding region were examined by polymerase chain reaction (PCR) direct sequencing; the acetylation status was obtained by measuring isoniazid (INH) and its metabolite, acetylisoniazid (AcINH) in plasma was obtained by using the liquid chromatography coupled to mass spectrometry. TB patients were distributed into two groups of fast and slow acetylators according to the acetylation index calculated based on the plasma concentration of INH in the 3rd hour (T3) after an oral dose. Our PCR analysis identified several alleles, where NAT2*4, NAT2*5A, NAT2*6A, and NAT2*13A were the most important. The concentrations of INH varied between 1.10 mg/L and 13.10 mg/L at the 3rd hour and between 0.1 and 9.5 mg/L at the 6th hour. The use of the acetylating index I₃ allowed the classification of tested patients into two phenotypic groups: slow acetylators (44.3% of TB patients), and rapid acetylators (55.7%). Patient’s acetylation profile provides valuable information on their therapeutic, pharmacological, and toxicological responses.

Interplay between bile acid metabolism and microbiota in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) physiopathology is multifactorial and roles for both microbiota and bile acid (BA) modifications have been proposed. We investigated role of dysbiosis, transit pattern and BA metabolism in IBS.

METHODS

Clinical data, serum, and stool samples were collected in 15 healthy subjects (HS), 16 diarrhea-predominant (IBS-D) and 15 constipation-predominant IBS (IBS-C). Fecal microbiota composition was analyzed by real-time PCR. Sera and fecal BA profiles, 7α-C4 levels, and in vitro BA transformation activity by fecal microbiota were measured by mass spectrometry. Serum Fibroblast Growth Factor 19 (FGF19) was assayed by ELISA.

KEYS RESULTS

Dysbiosis was present in IBS patients with an increase in Escherichia coli in IBS-D patients (p = 0.03), and an increase in Bacteroides (p = 0.01) and Bifidobacterium (p = 0.04) in IBS-C patients. Sera primary and amino-conjugated BA were increased in IBS-D (63.5 ± 5.5%, p = 0.01 and 78.9 ± 6.3%, p = 0.03) and IBS-C patients (55.9 ± 5.5%, p = 0.04 and 65.3 ± 6.5%, p = 0.005) compared to HS (37.0 ± 5.8% and 56.7 ± 8.1%). Serum 7α-C4 and FGF19 levels were not different among all three groups. Fecal primary BA were increased in IBS-D patients compared to HS, including chenodeoxycholic acid which has laxative properties (25.6 ± 8.5% vs 3.5 ± 0.6%, p = 0.005). Bile acid deconjugation activity was decreased in IBS-D (p = 0.0001) and IBS-C (p = 0.003) feces. Abdominal pain was positively correlated with serum (R = 0.635, p < 0.001) and fecal (R = 0.391, p = 0.024) primary BA.

CONCLUSIONS & INFERENCES

Different sera and fecal BA profiles in IBS patients could be secondary to dysbiosis and further differences between IBS-C and IBS-D could explain stool patterns. This study opens new fields in IBS physiopathology and suggests that modification of BA profiles could have therapeutic potential.

Acute Methiopropamine Intoxication After "Synthacaine" Consumption

Use of methiopropamine (MPA), a synthetic metamfetamine analog, has been detected since 2011 in Europe, but there is limited information on its acute toxicity. A 30-year-old man was admitted to the emergency department in a confused state, with paranoid delusion, auditory and visual hallucinatory experiences, and incoherent speech following the use of "synthacaine" (a slang term derived from "synthetic" and "cocaine"). Toxicological screening for pharmaceuticals and drugs of abuse by liquid chromatography-diode-array detector, gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS-MS) detected MPA, which was subsequently quantified by a specific LC-MS-MS method. Of note, 13 h after presentation to the emergency department, the plasma concentration of MPA was 14 ng/mL. This case report confirms the toxicity of MPA and the need for toxicological analysis to confirm the substance actually ingested by users of new psychoactive substances.