Confirmation of an IRAK3 polymorphism as a genetic marker predicting response to anti-TNF treatment in rheumatoid arthritis.

Several genetic variants in Toll-like receptor (TLR) and nuclear factor (NF)-κB signalling pathways have been reported associated with responsiveness to tumour necrosis factor inhibitor (anti-TNF) treatment in rheumatoid arthritis (RA). The present study was undertaken to replicate these findings. In a retrospective case-case study including 1007 Danish anti-TNF-treated RA patients, we genotyped 7 previously reported associated single-nucleotide polymorphisms (SNPs) in these pathways. Furthermore, 5 SNPs previously reported by our group were genotyped in a subcohort (N=469). Primary analyses validated the IRAK3 rs11541076 variant as associated (odds ratio (OR)=1.33, 95% confidence interval (CI): 1.00-1.77, P-value=0.047) with a positive treatment response (EULAR (European League Against Rheumatism) good/moderate vs none response at 4±2 months), and found the NLRP3 rs461266 variant associated (OR=0.75, 95% CI: 0.60-0.94, P=0.014) with a negative treatment response. Meta-analyses combining data from previous studies suggested smaller effect sizes of associations between variant alleles of CHUK rs11591741, NFKBIB rs3136645 and rs9403 and a negative treatment response. In conclusion, this study validates rs11541076 in IRAK3, a negative regulator of TLR signalling, as a predictor of anti-TNF treatment response, and suggests true positive associations of previously reported SNPs within genes encoding activators/inhibitors of NF-κB (CHUK, MYD88, NFKBIB, and NLRP3).

Genetically determined high activity of IL-12 and IL-18 in ulcerative colitis and TLR5 in Crohns disease were associated with non-response to anti-TNF therapy.

Anti-tumour necrosis factor-α (TNF-α) is used for treatment of severe cases of inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). However, one-third of the patients do not respond to the treatment. A recent study indicated that genetically determined high activity of pro-inflammatory cytokines, including interleukin-1ß (IL-1ß), IL-6 and interferon gamma (IFN-γ), are associated with non-response to anti-TNF therapy. Using a candidate gene approach, 21 functional single-nucleotide polymorphisms (SNPs) in 14 genes in the Toll-like receptors, the inflammasome and the IFNG pathways were assessed in 482 and 256 prior anti-TNF naïve Danish patients with CD and UC, respectively. The results were analysed using logistic regression (adjusted for age and gender). Eight functional SNPs were associated with anti-TNF response either among patients with CD (TLR5 (rs5744174) and IFNGR2 (rs8126756)), UC (IL12B (rs3212217), IL18 (rs1946518), IFNGR1 (rs2234711), TBX21 (rs17250932) and JAK2 (rs12343867)) or in the combined cohort of patient with CD and UC (IBD) (NLRP3 (rs10754558), IL12B (rs3212217) and IFNGR1 (rs2234711)) (P<0.05). Only the association with heterozygous genotype of IL12B (rs3212217) (OR: 0.24, 95% CI: 0.11-0.53, P=0.008) among patients with UC withstood Bonferroni correction for multiple testing. In conclusion, Our results suggest that SNPs associated with genetically determined high activity of TLR5 among patients with CD and genetically determined high IL-12 and IL-18 levels among patients with UC were associated with non-response. Further studies will evaluate whether these genes may help stratifying patients according to the expected response to anti-TNF treatment.

Systematic review and meta-analysis: pharmacogenetics of anti-TNF treatment response in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects ~1% of the Caucasian population. Over the last decades, the availability of biological drugs targeting the proinflammatory cytokine tumour necrosis factor α, anti-TNF drugs, has improved the treatment of patients with RA. However, one-third of the patients do not respond to the treatment. We wanted to evaluate the status of pharmacogenomics of anti-TNF treatment. We performed a PubMed literature search and all studies reporting original data on associations between genetic variants and anti-TNF treatment response in RA patients were included and results evaluated by meta-analysis. In total, 25 single nucleotide polymorphisms were found to be associated with anti-TNF treatment response in RA (19 from genome-wide association studies and 6 from the meta-analyses), and these map to genes involved in T cell function, NFκB and TNF signalling pathways (including CTCN5, TEC, PTPRC, FCGR2A, NFKBIB, FCGR2A, IRAK3). Explorative prediction analyses found that biomarkers for clinical treatment selection are not yet available.

Associations between functional polymorphisms in the NFκB signaling pathway and response to anti-TNF treatment in Danish patients with inflammatory bowel disease.

Antitumor necrosis factor-α (TNF-α) is used for treatment of severe cases of inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). However, one-third of the patients do not respond to the treatment. Genetic markers may predict individual response to anti-TNF therapy. Using a candidate gene approach, 39 mainly functional single nucleotide polymorphisms (SNPs) in 26 genes regulating inflammation were assessed in 738 prior anti-TNF-naive Danish patients with IBD. The results were analyzed using logistic regression (crude and adjusted for age, gender and smoking status). Nineteen functional polymorphisms that alter the NFκB-mediated inflammatory response (TLR2 (rs3804099, rs11938228, rs1816702, rs4696480), TLR4 (rs5030728, rs1554973), TLR9 (rs187084, rs352139), LY96 (MD-2) (rs11465996), CD14 (rs2569190), MAP3K14 (NIK) (rs7222094)), TNF-α signaling (TNFA (TNF-α) (rs361525), TNFRSF1A (TNFR1) (rs4149570), TNFAIP3(A20) (rs6927172)) and other cytokines regulated by NFκB (IL1B (rs4848306), IL1RN (rs4251961), IL6 (rs10499563), IL17A (rs2275913), IFNG (rs2430561)) were associated with response to anti-TNF therapy among patients with CD, UC or both CD and UC (P ⩽ 0.05). In conclusion, the results suggest that polymorphisms in genes involved in activating NFκB through the Toll-like receptor (TLR) pathways, genes regulating TNF-α signaling and cytokines regulated by NFκB are important predictors for the response to anti-TNF therapy among patients with IBD. Genetically strong TNF-mediated inflammatory response was associated with beneficial response. In addition, the cytokines IL-1ß, IL-6 and IFN-γ may be potential targets for treating patients with IBD who do not respond to anti-TNF therapy. These findings should be examined in independent cohorts before these results are applied in a clinical setting.

Nephrogenous cyclic AMP levels in primary hyperparathyroidism.

The clinical utility of urinary cyclic adenosine-3',5'-monophosphate (cAMP) determinations has been limited by the overlap between hyperparathyroid and normal patients. We evaluated the potential of the parathyroid hormone (PTH)-dependent, nephrogenous cAMP in the diagnosis of hyperparathyroidism. Twenty-three patients with primary hyperparathyroidism and 19 control subjects had two-hour urine collections and blood sampling at midpoint. Nephrogenous cAMP level was calculated as total urinary cAMP excretion minus the amount filtered. The total urinary cAMP excretion (micromols per gram of creatinine) was higher in hyperparathyroid patients (6.8 +/- .5 SE), but overlapped with values obtained in controls (2.9 +/- .15). The level of nephrogenous cAMP (percent of total) was also higher in hyperparathyroid patients (72.5 +/- 1.8) than controls (26.3 +/- 4.1) and clearly separated the groups. Determination of nephrogenous cAMP levels may be useful in the diagnosis of hyperparathyroidism.

Clinical resistance to vasopressin. Detection of antibody by hemagglutination.

We describe a patient with hypothalamic diabetes insipidus who after 20 years became refractory to the effect of commercial vasopressin injection. Vasopressin antibodies were measured using a sensitive hemagglutination technique. Resistance was associated with a high titer of antibodies that disappeared once vasopressin therapy was withdrawn and the diabetes insipidus was controlled with chlorpropamide. Antibodies were also measured in four additional patients with diabetes insipidus while they were or were not receiving vasopressin. A patient who had received the drug for only two years already had a substantial titer of antibodies to vasopressin, but in this case the response to the hormone was not impaired.

Total body retention of orally administered 47-calcium in primary hyperparathyroidism.

Using a whole body radiation detector, we have measured the total body retention of 47-Ca 7 days after oral administration of the isotope to patients with various disorders of calcium metabolism. The percent retention of 47-Ca given with 90 mg of unlabeled (carrier) calcium varied with the calcium metabolic status as follows: normals (n equals 14), 33-43 percent (mean 38); primary hyperparathyroidism (n equals 28), 32-74 percent (mean 52); idiopathic hypercalciuria (n equals 9), 34-49 percent (mean 42); and hypercalcemia of other etiology (n equals 3), 23-26 percent (mean 25). Almost half (13/28) of those with hyperparathyroidism showed a retention above 55 percent, distinguishing them from subjects with idiopathic hypercalciuria. Retention of 47-Ca correlated poorly with clinical measures of severity of hyperparathyroidism. When isotope was diluted with a smaller amount of carrier calcium (20 mg), retention was increaseed in normals (n equals 5) to 46-54 percent (mean 50) and in hyperparathyroidism (n equals 5) to 64-87 percent (mean 73). After surgical cure of hyperparathyroidism retention of isotope returned toward normal in 5 of 7 subjects. Whole body retention of orally administered 47-Ca may prove useful in detecting hyperparathyroidism in subjects with mild hypercalcemia or hypercalciuria.

Blood-to-cerebrospinal fluid barrier for cyclic adenosine monophosphate in man.

A definite blood to lumbar CSF barrier for cyclic adenosine monophosphate (cAMP) exists in man under physiologic conditions. Lumbar CSF cAMP level remained unchanged, while the CSF glucose level rose significantly after a glucagon hydrochloride infusion that caused a 40-fold increase in the plasma cAMP level.

Cerebrospinal fluid norepinephrine alterations during electrical stimulation of cerebellar, cerebral surfaces in epileptic patients.

Lumbar cerebrospinal fluid norepinephrine concentrations were determined by radioenzymatic assay in five epileptic patients receiving double-blind cerebellar stimulation and in three epileptic patients with subdural cerebral surface electrodes. Mean CSF norepinephrine levels were significantly elevated by chronic cerebellar stimulation and significantly depressed after intermittent cerebral cortical stimulation. Lumbar CSF cyclic adenosine monophosphate levels determined by radioimmunoassay were not significantly altered by either cerebellar or cerebral surface stimulation. Our study suggests that (1) electrical stimulation of the anterodorsal cerebellum in man evokes alterations in noradrenergic metabolism. Cerebellar stimulation-induced elevations in norepinephrine may inhibit cerebellar, cerebral, and spinal neuronal activity. In addition, (2) noradrenergic responses to brain surface stimulation may exhibit regional specificity, and (3) noradrenergic alterations evoked by cerebral surface stimulation may not mimic those induced in isolated brain preparations.

Significance of non-steady-state serum digoxin concentrations.

In order better to define the optimal time for sample collection, the authors examined the serial concentrations of digoxin in serum and urine of six hospitalized patients during the first 8 hours after administration of their maintenance doses of digoxin. Expressed as % of baseline value, mean serum digoxin concentrations 1/2, 1, 1 1/2, 2,4, 6, and 8 hours after administration of the drug were 167, 185, 228, 256, 175, 145, and 134%, respectively. Steady-state serum concentrations were not established until 6-8 hours after administration of the drug, and high serum values during the first 6 hours did not correlate with clinical and/or electrocardiographic evidence of digoxin toxicity. It is concluded that when serum digoxin levels are utilized as an index of digitalization or toxicity in patients on maintenance therapy, the blood samples should be drawn just prior to the daily dose and no sooner than 6 hours after administration of the drug.

Plasma testosterone, luteinizing hormone, and follicle-stimulating hormone after vasectomy.

Plasma testosterone, LH, and FSH were measured in 24 healthy subjects prior to and after bilateral vasectomy. No significant changes were noted in any of the hormones 42 and 87 days after surgery; this indicated that normal testicular function persisted during the period of study.

Elevations in cerebrospinal fluid norepinephrine during unilateral and bilateral cerebellar stimulation in man.

Lumbar cerebrospinal fluid (CSF) norepinephrine concentrations determined by radioenzymatic assay in four epileptic patients were significantly higher during either chronic unilateral or bilateral cerebellar stimulation than those determined after a 7-day period without stimulation. The mean CSF norepinephrine levels noted during these two modes of cerebellar stimulation were not significantly different. The percentage of increase in CSF norepinephrine in one patient receiving 200/sec stimulation was 3 times higher than those noted in the three patients undergoing 10/sec stimulation. These evoked alterations in norepinephrine metabolism may relate to the reported modulation of spasticity and cerebral neuronal excitability during chronic cerebellar stimulation. Lumbar CSF cyclic adenosine monophosphate levels determined by radioimmunoassay were not significantly altered by either mode or frequency of cerebellar stimulation.

Cerebrospinal fluid GABA reductions in seizure patients evoked by cerebellar surface stimulation.

Lumbar cerebrospinal fluid (CSF) gamma-aminobutyric acid (GABA) levels determined by fluorometric assay in four seizure patients were found to be significantly lower during bilateral, continuous cerebellar stimulation than those determined after a 7-day period without stimulation. The CSF GABA concentrations during chronic unilateral, alternating cerebellar stimulation were reduced in three seizure patients but unchanged in a fourth patient. The percentage decrease in CSF GABA appeared to be independent of cerebellar stimulation frequency. These findings suggest that GABA-mediated neuronal transmission is depressed during cerebellar surface stimulation and this evoked reduction in GABA activity may compromise the efficacy of cerebellar stimulation in the treatment of epilepsy. Lumbar CSF cyclic guanosine monophosphate levels determined by radioimmunoassay were not significantly altered by either mode or frequency of cerebellar stimulation.

Is the weight loss of hyperbaric habitation a disorder of osmoregulation?

To examine the weight loss of hyperbaric helium-oxygen habitation, we measured the exchange of liquids and calories in six men who lived in this atmosphere for 32 d. The maximum pressure was 49.5 ATA. The men lost 3.7-10.1 kg, in spite of warm ambient (31-32 degrees C) temperatures and adequate calories (2,737 kcal/d) provided for the sedentary ways of chamber living. Weight loss and a calculated fluid deficit were accompanied by significant hemoconcentration, shown by increases in serum proteins. These changes were followed by a rise in urinary aldosterone and vasopressin, but not thirst. Weight loss in hyperbaric atmospheres is probably multifactorial, but our data suggests an uncoupling of normal osmoregulation may have occurred in the present set of subjects. This may have been due to altered lung mechanics, increased catecholamines, or effects of high pressure on cellular responses to vasopressin.