Second-tier Testing for 21-Hydroxylase Deficiency in the Netherlands: A Newborn Screening Pilot Study

CONTEXT

Newborn screening (NBS) for classic congenital adrenal hyperplasia (CAH) consists of 17-hydroxyprogesterone (17-OHP) measurement with gestational age-adjusted cutoffs. A second heel puncture (HP) is performed in newborns with inconclusive results to reduce false positives.

OBJECTIVE

We assessed the accuracy and turnaround time of the current CAH NBS algorithm in comparison with alternative algorithms by performing a second-tier 21-deoxycortisol (21-DF) pilot study.

METHODS

Dried blood spots (DBS) of newborns with inconclusive and positive 17-OHP (immunoassay) first HP results were sent from regional NBS laboratories to the Amsterdam UMC Endocrine Laboratory. In 2017-2019, 21-DF concentrations were analyzed by LC-MS/MS in parallel with routine NBS. Diagnoses were confirmed by mutation analysis.

RESULTS

A total of 328 DBS were analyzed; 37 newborns had confirmed classic CAH, 33 were false-positive and 258 were categorized as negative in the second HP following the current algorithm. With second-tier testing, all 37 confirmed CAH had elevated 21-DF, while all 33 false positives and 253/258 second-HP negatives had undetectable 21-DF. The elevated 21-DF of the other 5 newborns may be NBS false negatives or second-tier false positives. Adding the second-tier results to inconclusive first HPs reduced the number of false positives to 11 and prevented all 286 second HPs. Adding the second tier to both positive and inconclusive first HPs eliminated all false positives but delayed referral for 31 CAH patients (1-4 days).

CONCLUSION

Application of the second-tier 21-DF measurement to inconclusive first HPs improved our CAH NBS by reducing false positives, abolishing the second HP, and thereby shortening referral time.

Donor metabolic characteristics drive effects of faecal microbiota transplantation on recipient insulin sensitivity, energy expenditure and intestinal transit time

OBJECTIVE

Bariatric surgery improves glucose metabolism. Recent data suggest that faecal microbiota transplantation (FMT) using faeces from postbariatric surgery diet-induced obese mice in germ-free mice improves glucose metabolism and intestinal homeostasis. We here investigated whether allogenic FMT using faeces from post-Roux-en-Y gastric bypass donors (RYGB-D) compared with using faeces from metabolic syndrome donors (METS-D) has short-term effects on glucose metabolism, intestinal transit time and adipose tissue inflammation in treatment-naïve, obese, insulin-resistant male subjects.

DESIGN

Subjects with metabolic syndrome (n=22) received allogenic FMT either from RYGB-D or METS-D. Hepatic and peripheral insulin sensitivity as well as lipolysis were measured at baseline and 2 weeks after FMT by hyperinsulinaemic euglycaemic stable isotope (²H₂-glucose and ²H₅-glycerol) clamp. Secondary outcome parameters were changes in resting energy expenditure, intestinal transit time, faecal short-chain fatty acids (SCFA) and bile acids, and inflammatory markers in subcutaneous adipose tissue related to intestinal microbiota composition. Faecal SCFA, bile acids, glycaemic control and inflammatory parameters were also evaluated at 8 weeks.

RESULTS

We observed a significant decrease in insulin sensitivity 2 weeks after allogenic METS-D FMT (median rate of glucose disappearance: from 40.6 to 34.0 µmol/kg/min; p<0.01). Moreover, a trend (p=0.052) towards faster intestinal transit time following RYGB-D FMT was seen. Finally, we observed changes in faecal bile acids (increased lithocholic, deoxycholic and (iso)lithocholic acid after METS-D FMT), inflammatory markers (decreased adipose tissue chemokine ligand 2 (CCL2) gene expression and plasma CCL2 after RYGB-D FMT) and changes in several intestinal microbiota taxa.

CONCLUSION

Allogenic FMT using METS-D decreases insulin sensitivity in metabolic syndrome recipients when compared with using post-RYGB-D. Further research is needed to delineate the role of donor characteristics in FMT efficacy in human insulin-resistant subjects.

TRIAL REGISTRATION NUMBER

NTR4327.

The effect of a diiodothyronine mimetic on insulin sensitivity in male cardiometabolic patients: a double-blind randomized controlled trial

Background and aims

Obesity and its associated cardiometabolic co-morbidities are increasing worldwide. Since thyroid hormone mimetics are capable of uncoupling the beneficial metabolic effects of thyroid hormones from their deleterious effects on heart, bone and muscle, this class of drug is considered as adjacent therapeutics to weight-lowering strategies. This study investigated the safety and efficacy of TRC150094, a thyroid hormone mimetic.

Materials and Methods

This 4-week, randomized, placebo-controlled, double-blind trial was conducted in India and The Netherlands. Forty subjects were randomized at a 1∶1 ratio to receive either TRC150094 dosed at 50 mg or placebo once daily for 4 weeks. Hyperinsulinemic euglycemic clamp and ¹H-Magnetic Resonance Spectroscopy (MRS) were performed before and after treatment.

Results

At baseline, subjects were characterized by markedly impaired hepatic and peripheral insulin sensitivity. TRC150094 dosed 50 mg once daily was safe and well tolerated. Hepatic nor peripheral insulin sensitivity improved after TRC150094 treatment, expressed as the suppression of Endogenous Glucose Production from 59.5 to 62.1%; p = 0.477, and the rate of glucose disappearance from 28.8 to 26.4 µmol kg⁻¹min⁻¹, p = 0.185. TRC150094 administration did not result in differences in fasting plasma free fatty acids from 0.51 to 0.51 mmol/L, p = 0.887 or in insulin-mediated suppression of lipolysis from 57 to 54%, p = 0.102. Also, intrahepatic triglyceride content was unaltered.

Conclusion

Collectively, these data show that, in contrast to the potent metabolic effects in experimental models, TRC150094 at a dose of 50 mg daily does not improve the metabolic homeostasis in subjects at an increased cardiometabolic risk. Further studies are needed to evaluate whether TRC150094 has beneficial effects in patients with more severe metabolic derangement, such as overt diabetes mellitus and hypertriglyceridemia.

Trial Registration

clinicaltrials.gov NCT01408667

Maintenance of peripheral naive T cells: a mouse-man divide (159.1)

Insights from T-cell dynamic studies in mice are widely extrapolated to men and vice versa, while no formal proof exists that such extrapolations are justified. At the same time, there is a lot of controversy about the dynamic properties of T cells, including life span and the relative contributions of thymus output and peripheral proliferation to the maintenance of the naive T-cell pool during aging. We have investigated the hypothesis that part of this controversy is due to improper extrapolation of dynamic parameters of T cells from mice to men. By combining in vivo kinetic labeling using deuterated water, thymectomy experiments, analysis of TRECs, the expression of the thymic proximity marker CD31, and mathematical modeling, we have quantified the contributions of de novo T-cell production by the thymus and peripheral naive T-cell division to life-long maintenance of the naive T-cell pool in both mice and men under normal physiological conditions. Our results show that mice and men are incomparable with respect to naive T-cell maintenance. While in mice - throughout their life time - the naive T-cell pool is almost exclusively sustained by thymus output, the maintenance of the adult human naive T-cell pool occurs almost exclusively through peripheral T-cell division. These findings put serious constraints on the use of mouse experiments to understand immunological processes such as T-cell reconstitution in lymphopenic patients or the effects of aging in healthy humans.

A rosiglitazone-induced increase in adiponectin does not improve glucose metabolism in HIV-infected patients with overt lipoatrophy

HIV-infected patients on antiretroviral therapy frequently develop changes in body fat distribution and disturbances in glucose metabolism, associated with reduced adiponectin levels. Because adiponectin, principally the high-molecular-weight (HMW) form, has insulin-sensitizing properties, we investigated the effects of an increase in adiponectin on glucose metabolism in HIV-lipodystrophy. In this randomized, double-blind, placebo-controlled trial, we included HIV-1-infected patients with severe lipoatrophy, with an undetectable viral load and who had received neither protease inhibitors nor stavudine for ≥6 mo. Patients were randomized to rosiglitazone [8 mg daily (n = 8)] to increase adiponectin levels or placebo (n = 5) for 16 wk. Peripheral glucose disposal, glucose production, and lipolysis were measured after an overnight fast and during a hyperinsulinemic-euglycemic clamp using stable isotopes. Body composition was assessed by computed tomography and dual-energy X-ray absorptiometry. Although body fat distribution was unaffected, rosiglitazone increased total plasma adiponectin levels by 107% (P < 0.02) and the ratio of HMW to total adiponectin by 73% (P < 0.001). In the placebo group, neither total adiponectin levels (P = 0.62) nor the ratio of HMW to total adiponectin changed (P = 0.94). The marked increase in adiponectin induced by rosiglitazone was not associated with significant changes in basal endogenous glucose production (P = 0.90), basal lipolysis (P = 0.90), insulin-mediated suppression of glucose production (P = 0.17) and lipolysis (P = 0.54) nor with changes in peripheral glucose disposal (P = 0.13). Acknowledging the limited statistical power of our small study, these findings, if confirmed by larger studies, could question the importance of adiponectin in regulating glucose metabolism in HIV-lipodystrophy.

A single bolus infusion of C-reactive protein increases gluconeogenesis and plasma glucose concentration in humans

Recently, we reported that C-reactive protein (CRP) elicits inflammatory and procoagulant responses in humans. In addition, CRP has been associated with the development of type 2 diabetes mellitus. To further explore interactions between CRP and glucose handling, we evaluated the effects of CRP infusion on glucose metabolism in humans. Seven healthy white male volunteers (age, 39.3 +/- 16.9 years) received a single bolus infusion of 1.25 mg/kg purified recombinant human (rh) CRP or CRP-free diluent in a crossover design. C-reactive protein infusion induced an inflammatory response, which was followed by increased plasma concentrations of norepinephrine (3 hours) and cortisol (4 hours). Concomitantly, plasma concentrations of insulin and C-peptide decreased transiently. These metabolic changes increased plasma glucose concentrations from 8 hours after CRP infusion, which was preceded by an increased rate of glucose appearance that was a direct consequence of increased gluconeogenesis. In conclusion, CRP infusion induces an inflammatory response followed by increased norepinephrine and cortisol levels, which results in increased gluconeogenesis. This finding implies that elevated levels of CRP in humans may in fact contribute to altered glucose metabolism and thereby may contribute to the induction of type 2 diabetes mellitus.

Association of insulin resistance with hyperglycemia in streptozotocin-diabetic pigs: effects of metformin at isoenergetic feeding in a type 2-like diabetic pig model

Insulin-mediated glucose metabolism was investigated in streptozotocin (STZ)-treated diabetic pigs to explore if the STZ-diabetic pig can be a suitable model for insulin-resistant, type 2 diabetes mellitus. Pigs (approximately 40 kg) were meal-fed with a low-fat (5%) diet. Hyperinsulinemic (1, 2, and 8 mU kg(-1) min(-1)) clamps and/or 6,6-(2)H-glucose infusion studies were performed in 36 pigs. Diabetic (slow, 30-minute infusion of 130 mg STZ/kg) vs normal pigs were nonketotic, showed fasting hyperglycemia (21.7 +/- 1.1 vs 5.3 +/- 0.2 mmol/L), comparable plasma insulin (9 +/- 7 vs 5 +/- 1 mU/L), and elevated triglyceride concentrations (1.0 +/- 0.3 vs 0.2 +/- 0.1 mmol/L). After a standard meal, plasma triglycerides, cholesterol, and nonesterified fatty acid concentrations were significantly higher in diabetic vs normal pigs (1.2 +/- 0.3 vs 0.3 +/- 0.1, 2.3 +/- 0.2 vs 1.7 +/- 0.1, and 1.5 +/- 0.5 vs 0.2 +/- 0.1 mmol/L, respectively, P < .05). Fasting whole-body glucose uptake, hepatic glucose production, and urinary glucose excretion were increased (P < .01) in diabetic vs normal pigs (9.1 +/- 0.6 vs 4.8 +/- 0.4, 11.4 +/- 0.6 vs 4.8 +/- 0.4, and 2.3 +/- 0.2 vs 0.0 +/- 0.0 mg kg(-1) min(-1)). During hyperinsulinemic euglycemia (approximately 6 mmol/L), whole-body glucose uptake was severely reduced (P < .01) and hepatic glucose production was moderately increased (P < .05) in diabetic vs normal pigs (6.7 +/- 1.3 vs 21.1 +/- 2.2 and 1.7 +/- 0.5 vs 0.8 +/- 0.3 mg kg(-1) min(-1)) despite plasma insulin concentrations of 45 +/- 5 vs 24 +/- 5 mU/L, respectively. Metformin vs placebo treatment of diabetic pigs (twice 1.5 g/d) for 2 weeks during isoenergetic feeding (1045 kJ/kg body weight(0.75)) resulted in a reduction in both fasting and postprandial hyperglycemia (14.7 +/- 1.5 vs 19.4 +/- 0.6 and 24.9 +/- 2.2 vs 35.5 +/- 4.9 mmol/L), a reduction in daily urinary glucose excretion (approximately 250 vs approximately 350 g/kg food), and an increase in insulin-stimulated glucose disposal (9.4 +/- 2.2 vs 5.8 +/- 1.7 mg kg(-1) min(-1); P < .05), respectively. In conclusion, a slow infusion of STZ (130 mg/kg) in pigs on a low-fat diet induces the characteristic metabolic abnormalities of type 2 diabetes mellitus and its sensitivity to oral metformin therapy. It is therefore a suitable humanoid animal model for studying different aspects of metabolic changes in type 2 diabetes mellitus. Insulin resistance in STZ-diabetic pigs is most likely secondary to hyperglycemia and/or hyperlipidemia and therefore of metabolic origin.

The maximal tolerable intravenous dosage of pentoxifylline in AIDS patients does not inhibit lipopolysaccharide-stimulated tumor necrosis factor alpha production

Tumor necrosis factor alpha (TNF-alpha) may be involved in the pathogenesis of metabolic and endocrine changes in HIV infection. Pentoxifylline (PTX) is able to suppress the production of TNF-alpha in vitro. The effect of two dosages of intravenously administered PTX on clinical symptoms and ex vivo LPS-stimulated TNF-alpha production was evaluated in six clinically stable AIDS patients in a saline-controlled study. PTX in a dosage of 1.5 mg/min was tolerated without side effects. PTX in a dosage of 2.1 mg/min resulted in intolerable nausea and necessitated termination of infusion after 30 min. The average plasma concentration of PTX after infusion of 1.5 mg/min for 6 hr was 510+/-56 ng/ml, which is considerably below the concentrations that have been reported to suppress TNF-alpha production in vitro. No effect of PTX infusion (1.5 mg/min) on LPS-stimulated TNF production ex vivo was found. Our conclusion is that the maximally tolerated i.v. dosage of PTX in AIDS patients is 1.5 mg/min. LPS-stimulated ex vivo TNF-alpha production, at the LPS concentrations tested, was not inhibited by the plasma concentration of PTX that could be achieved at this dosage.

Liquorice-induced hypertension--a new understanding of an old disease: case report and brief review

The case is described of a 40-year-old female with severe hypertension and hypokalaemic metabolic alkalosis, due to prolonged liquorice ingestion. The pseudo-aldosterone-like effects of liquorice have always been attributed to glycyrrhizic acid, but its biochemical substrate has remained elusive. It is now known that glycyrrhetenic acid, the hydrolytic metabolite of glycerrhizic acid, is the active component of liquorice which causes inhibition of the peripheral metabolism of cortisol. Cortisol binds with the same affinity as aldosterone to the mineralocorticoid receptor resulting in a hypermineralocorticoid condition. Ingestion of liquorice may therefore result in retention of sodium and water, hypertension, hypokalaemia, alkalosis and suppression of the renin-aldosterone system. The literature on liquorice-induced hypertension is briefly reviewed with emphasis on the biochemical features of this mineralocorticoid excess syndrome.

Improved method for the determination of serotonin in plasma by high-performance liquid chromatography using on-line sample pre-treatment

An improved method for the determination of serotonin in platelet-rich plasma (PRP) and platelet-poor plasma (PPP), by reversed-phase high-performance liquid chromatography with electrochemical detection and direct plasma injection, is described. The chromatographic system comprises a strong cation-exchange pre-column and a C18 analytical column. The method is selective, rapid, simple and sensitive, and offers good reproducibility and recovery. Reference values for serotonin concentrations in healthy adults (n = 10) are 31 nM for PPP and 6 nmol per 10(9) platelets for PRP. The conditions used for the preparation of PRP and PPP may influence the serotonin concentration in PRP.