Blood gene expression biomarkers of response to anti-TNF drugs in pediatric inflammatory bowel diseases before initiation of treatment

BACKGROUND/AIMS

Changes in gene expression profiles among individuals with inflammatory bowel diseases (IBDs) could potentially influence the responsiveness to anti-TNF treatment. The aim of this study was to identify genes that could serve as predictors of early response to anti-TNF therapies in pediatric IBD patients prior to the initiation of treatment.

METHODS

We conducted a prospective, longitudinal, and multicenter study, enrolling 24 pediatric IBD patients aged less than 18 years who were initiating treatment with either infliximab or adalimumab. RNA-seq from blood samples was analyzed using the DESeq2 library by comparing responders and non-responders to anti-TNF drugs.

RESULTS

Bioinformatic analyses unveiled 102 differentially expressed genes, with 99 genes exhibiting higher expression in responders compared to non-responders prior to the initiation of anti-TNF therapy. Functional enrichment analyses highlighted defense response to Gram-negative bacteria (FDR = 2.3 ×10-7) as the most significant biological processes, and hemoglobin binding (FDR = 0.002), as the most significant molecular function. Gene Set Enrichment Analysis (GSEA) revealed notable enrichment in transcriptional misregulation in cancer (FDR = 0.016). Notably, 13 genes (CEACAM8, CEACAM6, CILP2, COL17A1, OLFM4, INHBA, LCN2, LTF, MMP8, DEFA4, PRTN3, AZU1, and ELANE) were selected for validation, and a consistent trend of increased expression in responders prior to drug administration was observed for most of these genes, with findings for 4 of them being statistically significant (CEACAM8, LCN2, LTF2, and PRTN3).

CONCLUSIONS

We identified 102 differentially expressed genes involved in the response to anti-TNF drugs in children with IBDs and validated CEACAM8, LCN2, LTF2, and PRTN3. Genes participating in defense response to Gram-negative bacterium, serine-type endopeptidase activity, and transcriptional misregulation in cancer are good candidates for anticipating the response to anti-TNF drugs in children with IBDs.

Polymorphisms indicating risk of inflammatory bowel disease or antigenicity to anti-TNF drugs as biomarkers of response in children

Few genetic polymorphisms predict early response to anti-TNF drugs in inflammatory bowel disease (IBD), and even fewer have been identified in the pediatric population. However, it would be of considerable clinical interest to identify and validate genetic biomarkers of long-term response. Therefore, the aim of the study was to analyze the usefulness of biomarkers of response to anti-TNFs in pediatric IBD (pIBD) as long-term biomarkers and to find differences by type of IBD and type of anti-TNF drug. The study population comprised 340 children diagnosed with IBD who were treated with infliximab or adalimumab. Genotyping of 9 selected SNPs for their association with early response and/or immunogenicity to anti-TNFs was performed using real-time PCR. Variants C rs10508884 (CXCL12), A rs2241880 (ATG16L1), and T rs6100556 (PHACTR3) (p value 0.049; p value 0.03; p value 0.031) were associated with worse long-term response to anti-TNFs in pIBD. DNA variants specific to disease type and anti-TNF type were identified in the pediatric population. Genotyping of these genetic variants before initiation of anti-TNFs would enable, if validated in a prospective cohort, the identification of pediatric patients who are long-term responders to this therapy.

Association between HLA DNA Variants and Long-Term Response to Anti-TNF Drugs in a Spanish Pediatric Inflammatory Bowel Disease Cohort

The genetic polymorphisms rs2395185 and rs2097432 in HLA genes have been associated with the response to anti-TNF treatment in inflammatory bowel disease (IBD). The aim was to analyze the association between these variants and the long-term response to anti-TNF drugs in pediatric IBD. We performed an observational, multicenter, ambispective study in which we selected 340 IBD patients under 18 years of age diagnosed with IBD and treated with anti-TNF drugs from a network of Spanish hospitals. Genotypes and failure of anti-TNF drugs were analyzed using Kaplan-Meier curves and Cox logistic regression. The homozygous G allele of rs2395185 and the C allele of rs2097432 were associated with impaired long-term response to anti-TNF drugs in children with IBD after 3 and 9 years of follow-up. Being a carrier of both polymorphisms increased the risk of anti-TNF failure. The SNP rs2395185 but not rs2097432 was associated with response to infliximab in adults with CD treated with infliximab but not in children after 3 or 9 years of follow-up. Conclusions: SNPs rs2395185 and rs2097432 were associated with a long-term response to anti-TNFs in IBD in Spanish children. Differences between adults and children were observed in patients diagnosed with CD and treated with infliximab.

The use of amino acid formulas in pediatric patients with allergy to cow's milk proteins: Recommendations from a group of experts

One of the most common food allergies in children is cow's milk allergy (CMA). In breast-fed infants with CMA, the mother is encouraged to avoid dairy products. If this is not possible, or in formula fed infants, use of hypoallergenic replacement formulas such as extensively hydrolyzed formulas (EHF) is recommended. However, in ∼5% of patients EHFs are not tolerated and/or allergy symptoms can persist. When EHFs are ineffective and in severe forms of CMA, amino acid-based formulas (AAF) should be considered. Six pediatric gastroenterologists with extensive experience in food allergy management reviewed scientific publications and international clinical practice guidelines to provide practical recommendations on AAF. The guidelines reviewed had discrepancies and ambiguities around the specific indications for using formulas as a milk substitute. The panel recommends AAFs as the first therapeutic option in anaphylaxis due to CMA, in acute and chronic severe food protein-induced enterocolitis syndrome, in CMA associated with multiple food allergy, and in cases of eosinophilic esophagitis not responding to an extended exclusion diet or not eating solids. The main benefit of AAF is its absence of residual allergenicity, making it a safe treatment option in severe CMA patients who do not tolerate or respond to an EHF.

Long-Term Outcome of Children with Short Bowel Syndrome Treated with a Modification of the STEP Technique Avoiding Mesenteric Defect

BACKGROUND

 The Serial Transverse Enteroplasty Procedure (STEP) Registry has reported a 47% success to achieve enteral autonomy in pediatric short bowel syndrome (SBS). We have performed the STEP with a technical modification (MSTEP) consisting in stapler application without mesenteric defects that can also be applied to the duodenum. Our experience with this technique is described.

MATERIALS AND METHODS

 In this study, 16 children with SBS underwent MSTEP (2005-2019). Indications were nutritional autonomy achievement (n = 11, with duodenal lengthening in 5/11) and bacterial overgrowth treatment (n = 5).

RESULTS

 With a median follow-up of 5.8 years (0.7-13.7 years), 5 of 11 (45%) patients achieved enteral autonomy, 4 of them with duodenal lengthening. Four of four who preserved > 50% colon, while only one of seven with < 50% of colon achieved enteral autonomy (p < 0.05). After redo procedures, three of four attained enteral autonomy. Thus, 8 of 11 (73%) progressed to enteral autonomy, including all with duodenal lengthening. One child, already parenteral nutrition free, died due to central line sepsis. All the patients from the bacterial translocation group improved their metabolic/nutritional status, but one required subsequent enterectomy of the lengthened intestine due to multiple ulcers in the staple lines.

CONCLUSION

 The effectiveness of MSTEP to achieve enteral autonomy seems similar to the classical STEP. It can be applied to the duodenum. The retained colon length may influence the post-STEP enteral autonomy achievement.

COVID-19 Gastrointestinal Manifestations Are Independent Predictors of PICU Admission in Hospitalized Pediatric Patients

Multicenter study conducted in 15 hospitals including 101 COVID-19 pediatric inpatients aiming to describe associated gastrointestinal (GI) manifestations. GI symptoms were present in 57% and were the first manifestation in 14%. Adjusted by confounding factors, those with GI symptoms had higher risk of pediatric intensive care unit admission. GI symptoms are predictive of severity in COVID-19 children admitted to hospitals.

Pharmacogenetics of trough serum anti-TNF levels in paediatric inflammatory bowel disease

AIMS

Identifying DNA variants associated with trough serum anti-tumour necrosis factor (TNF) levels could predict response to treatment in inflammatory bowel disease (IBD). To date, no specific studies have been performed in children. The aim of this study was to identify genetic variants associated with trough serum anti-TNF levels and whether these variants are differential markers for infliximab and adalimumab.

METHODS

We included 154 children (age < 18 years) from 17 hospitals who had been diagnosed with IBD and actively treated with infliximab or adalimumab. Twenty-one polymorphisms were genotyped using real-time PCR. Trough serum anti-TNF levels were measured using enzyme-linked immunosorbent assay (ELISA). The association between DNA polymorphisms and the therapeutic range or the absolute values of anti-TNF drugs was analysed by Fisher exact test, student's t-test and logistic regression.

RESULTS

The variants rs5030728 (TLR4) and rs11465996 (LY96) were associated with subtherapeutic infliximab levels. rs1816702 (TLR2) was associated with supratherapeutic levels and rs3397 (TNFRSF1B) with subtherapeutic levels of adalimumab (P < .05). In addition, rs1816702 (TLR2) and rs2569190 (CD14) were associated with absolute values of trough serum adalimumab, and rs2569190 (CD14) was associated with absolute values of trough serum adalimumab and infliximab (P < .05).

CONCLUSION

Genotyping of these DNA variants before starting treatment may help to select the best anti-TNF drug in paediatric patients. The SNP rs1816702 is the most promising marker for tailoring the anti-TNF regimen in children with IBD. For the first time, DNA variants are associated with trough serum anti-TNF levels.

Severe renal Fanconi and management strategies in Arthrogryposis-Renal dysfunction-Cholestasis syndrome: a case report

Background

Arthrogryposis-Renal dysfunction-Cholestasis syndrome (ARC, MIM#208085) is a rare multisystem disease due to mutations in the VPS33B and VIPAR genes, both involved in maintaining apical-basolateral cell polarity. The correlation between mutations and phenotype in the ARC Syndrome is not well described. We report on a 6 year old patient who presented with severe renal Fanconi as first manifestation of ARC related to a combined de novo mutation in the VPS33B gene.

Case presentation

A 6 year old girl presented during the first year of life with severe renal Fanconi as the first manifestation of ARC-Syndrome. This case presents all defining features of ARC syndrome (including liver, skin and articular manifestations) with predominantly renal impairment at presentation. This novel mutation may be associated with a pronounced renal phenotype in ARC. Furthermore, we report on the successful use of LDL-Apheresis and biliodigestive derivation for treatment of cholestatic pruritus with encouraging results.

Conclusion

ARC is a heterogeneous disorder with early mortality. This case report contributes to a better understanding of this rare disorder, describes a novel mutation in the VPS33B gene and presents an innovative rescue treatment approach.

Duodenal lengthening in short bowel with dilated duodenum

Although duodenal dilatation occurs in children with short bowel syndrome (SBS) facilitating dismotility and bacterial overgrowth, the duodenum has been an untouchable intestinal segment for lengthening procedures owing to its close relationship with bilio-pancreatic structures and blood supply shared with the pancreas. Three children (age range, 0.5-7 years) with SBS and dilated duodenum underwent a novel surgical procedure of duodenal lengthening combined with a technical modification of serial transverse enteroplasty (STEP). Pre-STEP, jejunum length was 5, 35 and 45cm, respectively. Duodenal lengthening was performed with sequential transverse applications of an endoscopic stapler on the anterior and posterior wall of the duodenum to avoid bilio-pancreatic structure injury. Two patients underwent 3 duodenal firings (stapler of 35mm) and the third 5 firings (stapler of 45mm). Duodenal firings were 17%, 21% and 83% of the total firings.

RESULTS

No surgical complications occurred. One patient developed transient episodes of D-lactic acidosis. Two patients (5 and 45cm) were weaned off parenteral nutrition at 12months post-surgery and the remaining patient´s (35cm) parenteral calorie requirements have decreased by 60%.

CONCLUSION

Duodenal lengthening is effective since it tailors and increases the absorptive surface of the duodenum, even in cases of extreme SBS.

PRESENT; PREScription of Enteral Nutrition in pediaTric Crohn's disease in Spain

OBJECTIVES

Exclusive enteral nutrition (EEN) is one of the therapeutic strategies used to induce remission in pediatric Crohn's disease (CD). Although its use is recommended in clinical practice guidelines and consensus documents, the frequency of this practice in Spain is unknown.

METHODS

A 70-item questionnaire (

PRESENT

PREScription of Enteral Nutrition in pediaTric Crohn's disease in Spain) was drafted and distributed through the SEGHNP (Spanish Society for Pediatric Gastroenterology, Hepatology and Nutrition) e-mail list.

RESULTS

We received information from 51 Pediatric Gastroenterology Units. Of the 287 patients newly diagnosed with CD in 2011-2012 at these centres (139 in 2011, 148 in 2012), 182 (63%) received EEN (58% in 2011 and 68% in 2012). 26% of the patients who received EEN in the period studied (64/246) did so during relapses. All the physicians (100%) who responded to the questionnaire believe that EEN is effective in inducing clinical remission in mild to moderate CD. However, 24.5% of respondents never use EEN during relapses. The enteral formulas used most often used were polymeric formulas specific for CD (70.6%) and the preferred administration route was oral, with 60.8% using flavouring and 9.3% allowing a variable percentage of calories in the form of other foods. 65% use 5-ASA together with EEN, 69% use antibiotics and 95% immunomodulators (thiopurines). The duration of EEN tends to be 8 weeks (47.1%), and transition to regular diet was achieved sequentially over a variable period of time. Regarding barriers and limiting factors for the use of EEN, those most frequently reported include lack of acceptance by the patient and/or family (71%), lack of time and/or ancillary staff (69%) and difficulty in convincing the patient and/or family of the suitability of treatment (43%).

CONCLUSIONS

EEN use rates are similar to those of other European questionnaires. Tools that facilitate acceptance by the patient and family are needed. Increasing the time dedicated to this therapeutic modality is likewise important. Given the disparity of criteria for indicating treatment with EEN, it would be useful to have widely accepted clinical practice guidelines or protocols that facilitate the decision to use it.

Dietary treatment of colic caused by excess gas in infants: Biochemical evidence

AIM: To evaluate the impact of feeding colicky infants with an adapted formula on the hydrogen breath test and clinical symptoms.

METHODS: Hydrogen expiration was measured by SC MicroLyzer gas chromatography at inclusion and 15 d after treatment with an adapted low-lactose formula in 20 colicky infants.

RESULTS: All babies were symptomatic: 85% with excess gas, 75% with abnormal feeding pattern, and 85% with excessive crying. The hydrogen breath test at inclusion was abnormal: 35 ± 3.1 ppm. After 15 d feeding with an adapted low-lactose formula, crying and flatulence decreased in 85% of patients (P < 0.001). For infants in whom no decrease of gas was reported, crying was still reduced (P < 0.01). Moreover, the feeding pattern was improved in 50% of infants when it was initially considered as abnormal. Finally, the hydrogen breath test decreased significantly (10 ± 2.5 ppm, P < 0.01).

CONCLUSION: This study showed an association between clinical improvement and evidence of decreased levels of hydrogen when the infants were fed with a specially designed, low-lactose formula.

Effects of cocaine administration on VTA cell activity in response to prefrontal cortex stimulation

The repeated use of psychostimulants in humans has been associated with progressive enhancement of anxiety, panic attacks, and eventually paranoid psychosis. The appearance of such behaviors has been termed behavioral sensitization, which forms part of the basic pathological mechanisms involved in drug addiction. Psychostimulants act via a circuit involving the ventral tegmental area (VTA), prefrontal cortex (PFC), and nucleus accumbens. The PFC sends glutamatergic projections that activate dopaminergic neurons in the VTA. These projections provide an extremely important excitatory drive necessary for the development of sensitization. The effects of cocaine administration on the response of dopaminergic VTA cells to activation of the PFC have not been reported. Here the effects of acute cocaine administration on VTA cell response to PFC stimulation are examined. Statistical analysis of the changes in spontaneous activity and evoked response revealed a significant decrease in spontaneous activity at 1.0 mg/kg i.v. after cocaine treatment compared to baseline levels. The net effect was an increase in signal-to-noise ratio. Treatment with MK-801 at a dose of 2 mg/kg showed that the excitatory response was, at least partially, NMDA-mediated. Prazosin pretreatment (0.5 mg/kg i.p.) did not prevent a significant decrease in spontaneous activity brought about by cocaine (15 mg/kg, i.p.). Nonetheless, prazosin alone induced a significant decrease in the response to PFC stimulation when compared to baseline. In addition, iontophoretic application of norepinephrine (NE) onto VTA cells revealed that NE potentiated (19.2%), enhanced (26.9%), or suppressed (46.2%) the glutamate-evoked response in VTA cells. The results suggest that a possible role of cocaine in the process of sensitization might be to amplify the PFC-induced excitation at the VTA. Since the iontophoretic release of NE in almost half of the sampled cells produced similar effects to those of cocaine it may suggest a possible NE-mediated mechanism for cocaine actions.

Effects of intravenous cocaine administration on cerebellar Purkinje cell activity

The goal of the present study was to investigate the effects of intravenous cocaine administration on cerebellar Purkinje cell firing. Extracellular neuron activity was recorded and cells were locally excited with spaced microiontophoretic pulses of glutamate. Glutamate-evoked and spontaneous discharges were compared before and immediately following cocaine administration. Cocaine injections (1. 0 and 0.25 mg/kg, i.v.) induced a reversible suppression of both spontaneous activity and glutamate-evoked excitation. Procaine was ineffective in producing similar actions. Cocaine only inhibited glutamate-induced excitation in animals pre-treated with reserpine (5 mg/kg, i.p.). Propranolol injections (10 mg/kg, i.p.) were ineffective in blocking cocaine-induced inhibitions. Yohimbine (5 mg/kg, i.p.) pre-treatment abolished cocaine-induced suppressions of either spontaneous or glutamate-evoked excitation. Therefore, cocaine administration decreases Purkinje cell spontaneous and glutamate-evoked discharges by a mechanism involving alpha(2)-adrenoceptor activation. It is suggested that by changing the normal function of the cerebellum cocaine can produce drug-related alterations in overt behavior and cognition.

Chronic imipramine treatment induces downregulation of alpha-2 receptors in rat's locus coeruleus and A2 region of the tractus solitarius

Imipramine is an effective antidepressant agent that blocks the reuptake of monoamines. In order to understand some of its basic mechanisms of action, we investigated the effects of chronic imipramine administration (10 mg/kg, i.p.; 21 days) on the alpha-2 receptor population of several brain sites. Alpha-2 receptor density was estimated by in vitro autoradiography using [3H]Idazoxan. The densitometric analysis revealed a decreased receptor density in the A2 region of the tractus solitarius (20%) and locus coeruleus (16%). No changes were observed in the amygdala, pyriform cortex, periacueductal gray and the bed nucleus of the stria terminalis. These results suggest that chronic imipramine treatment selectively modulates the alpha-2 receptor population localized in the brain stem norepinephrine-rich nuclei and not in the population present on limbic structures innervated by noradrenergic terminal projections. The possible physiological consequences of this selective modulation of alpha-2 receptors are discussed.