Author Archives: gutsandgrowth

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About gutsandgrowth

I am a pediatric gastroenterologist at GI Care for Kids (previously called CCDHC) in Atlanta, Georgia. The goal of my blog is to share some of my reading in my field more broadly. In addition, I wanted to provide my voice to a wide range of topics that often have inaccurate or incomplete information. Before starting this blog in 2011, I would tear out articles from journals and/or keep notes in a palm pilot. This blog helps provide an updated source of information that is easy to access and search, along with links to useful multimedia sources. I was born and raised in Chattanooga. After graduating from the University of Virginia, I attended Baylor College of Medicine. I completed residency and fellowship training at the University of Cincinnati at the Children’s Hospital Medical Center. I received funding from the National Institutes of Health for molecular biology research of the gastrointestinal tract. During my fellowship, I had the opportunity to work with some of the most amazing pediatric gastroenterologists and mentors. Some of these individuals included Mitchell Cohen, William Balistreri, James Heubi, Jorge Bezerra, Colin Rudolph, John Bucuvalas, and Michael Farrell. I am grateful for their teaching and their friendship. During my training with their help, I received a nationwide award for the best research by a GI fellow. I have authored numerous publications/presentations including original research, case reports, review articles, and textbook chapters on various pediatric gastrointestinal problems. In addition, I have been recognized by Atlanta Magazine as a "Top Doctor" in my field multiple times. Currently, I am the vice chair of the section of nutrition for the Georgia Chapter of the American Academy of Pediatrics. In addition, I am an adjunct Associate Clinical Professor of Pediatrics at Emory University School of Medicine. Other society memberships have included the North American Society for Pediatric Gastroenterology Hepatology and Nutrition (NASPGHAN), American Academy of Pediatrics, the Food Allergy Network, the American Gastroenterology Association, the American Association for the Study of Liver Diseases, and the Crohn’s and Colitis Foundation. As part of a national pediatric GI organization called NASPGHAN (and its affiliated website GIKids), I have helped develop educational materials on a wide-range of gastrointestinal and liver diseases which are used across the country. Also, I have been an invited speaker for national campaigns to improve the evaluation and treatment of gastroesophageal reflux disease, celiac disease, eosinophilic esophagitis, hepatitis C, and inflammatory bowel disease (IBD). Some information on these topics has been posted at my work website, www.gicareforkids.com, which has links to multiple other useful resources. I am fortunate to work at GI Care For Kids. Our group has 17 terrific physicians with a wide range of subspecialization, including liver diseases, feeding disorders, eosinophilic diseases, inflammatory bowel disease, cystic fibrosis, DiGeorge/22q, celiac disease, and motility disorders. Many of our physicians are recognized nationally for their achievements. Our group of physicians have worked closely together for many years. None of the physicians in our group have ever left to join other groups. I have also worked with the same nurse (Bernadette) since I moved to Atlanta in 1997. For many families, more practical matters about our office include the following: – 14 office/satellite locations – physicians who speak Spanish – cutting edge research – on-site nutritionists – on-site psychology support for abdominal pain and feeding disorders – participation in ImproveCareNow to better the outcomes for children with inflammatory bowel disease – office endoscopy suite (lower costs and easier scheduling) – office infusion center (lower costs and easier for families) – easy access to nursing advice (each physician has at least one nurse) I am married and have two sons (both adults). I like to read, walk/hike, bike, swim, and play tennis with my free time. I do not have any financial relationships with pharmaceutical companies or other financial relationships to disclose. I have helped enroll patients in industry-sponsored research studies.

Don’t forget the liver for APC patients

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A recent case report serves a useful reminder that patients with APC gene mutation are at risk for hepatoblastoma (JPGN 2012; 55: 334-36).  A comprehensive review on this subject and APC gene disorders in general (along with related disorders) can be found at the following link: (APC-Associated Polyposis Conditions – GeneReviews™ – NCBI …)

One of the authors of the online link is a well-established expert in the field (Randall W Burt, MD) and updated the link in October 2011.

With regard to hepatoblastoma:

“The risk for hepatoblastoma in FAP is 750 to 7500 times higher than in the general population, although the absolute risk is estimated at less than 2%. The majority of hepatoblastomas occur prior to age three years.”

Screening for hepatoblastoma in FAP?

“Efficacy in individuals with FAP is unclear. Screening protocols in Beckwith-Wiedemann syndrome, in which the risk for hepatoblastoma is also increased, often include frequent (every 2-3 months) abdominal ultrasound examinations and measurement of serum alpha-fetoprotein concentrations and have resulted in early detection of hepatoblastomas. Screening for hepatoblastoma in FAP using the same protocol may be considered from infancy to age five years. However, the optimal interval for hepatoblastoma screening in FAP is not known, although it has been recommended that screening should occur at least every three months.”

Additional references:

  • -Liver Tx 2008; 14: 1545.  Reviews predisposing conditions to hepatoblastoma & HCC, screening & Rx.  Disorders include Beckwith-Wiedeman, FAP, tyrosinemia, GSD type II, PFIC type 2, Alagille, EHBA, HBV, TPN-cholestasis/extreme prematurity.
  • -J Pediatr 2005; 146: 204.  Review of Cincy experience and algorithm for hepatoblastoma management.
  • -H F A Vasen, G M G Möslein, A Alonso, et al. Guidelines for the clinical management of Familial adenomatous polyposis (FAP) Gut 2008 57: 704-713
  • -Polymnia Galiatsatos, ,William D. Foulkes. Familial Adenomatous Polyposis Am J Gastroenterol 2006;101:385–398
  • -Gastroenterol 2001; 121: 195-197 &198-213. Guidelines & technical review of genetic testing for FAP & HNPCC.

How new therapies impact colectomy in UC patients

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Has the need for colectomy changed with the increasing use of more potent medical therapies for ulcerative colitis (UC)?  One article gives some insight into this question (Inflamm Bowel Dis 2012; 18: 1641-46).

This French study followed 151 patients with newly diagnosed UC from 2000-2008; median followup was 58 months. During this time, 21 patients (14%) underwent colectomy.  1.3% required colectomy in the first year following diagnosis.

Looking closer at their study, 55% of patients had pancolitis.  Cyclosporin usage, typically given in refractory cases, was the only medication determined to be a predictive factor for surgery.

Medication usage during study period:

  • 68% oral mesalamine products
  • 72% systemic corticosteroids
  • 7% methotrexate
  • 49% azathioprine
  • 9% cyclosporin
  • 30% had received at least one anti-TNF agent

The authors concede several limitations, including the evolving nature of UC treatment.  Yet, they conclude that colectomy still is frequently needed and the use of IBD medications, including anti-TNF, “does not appear to reduce the long-term need for surgery in UC.”

I take issue with the last sentence.  Whether anti-TNF agents prove to be a disease-modifying treatment over the long-term is not known.  In this particular cohort, only 30% were even exposed to these agents.  My conclusion: we need a study designed to answer the question.  This would require larger numbers of patients followed prospectively for many years.

Related blog entries:

Itchy and Scratchy

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On TV’s “The Simpsons,” “Itchy” is a sadistic blue mouse and “Scratchy” is a hapless black cat (The Itchy & Scratchy Show – Wikipedia, the free encyclopedia, The Simpsons – Itchy and Scratchy – YouTube).  In real life being real itchy is not a joke; it is a common problem with cholestatic liver disease.  Beneficial treatments for pruritus may be partly due to their effects on serum autotaxin (Hepatology 2012; 56: 1391-1400, editorial 1194).

In this study, blood was drawn from different treatment groups:

  • 17 patients receiving colsevelam (a bile acid sequestrant)
  • 10 patients receiving MARS (molecular absorbance recirculating system)
  • 6 patients receiving rifampicin
  • 5 patients receiving nasobiliary drainage
  • Also, autotaxin levels were drawn from healthy controls, atopic dermatitis, Hodgkin’s disease (with and without pruritus), uremic patients, and cholestatic patients without pruritus

The most common diagnosis in all of the cholestatic groups was primary biliary cirrhosis; though some patients had primary sclerosing cholangitis, progressive familial intrahepatic cholestasis, benign recurrent intrahepatic cholestasis or other liver disorders.

Key findings:

  • Serum autotaxin is increased in pruritic cholestatic liver patients but not in other forms of pruritus.  In addition, autotaxin is normal in cholestatic patients without pruritus.
  • The level of autotaxin correlates closely with the effectiveness of the treatment as gauged by itch intensity

The reasons for pruritus in cholestasis have not been clear.  Several theories have been advanced regarding pathogenesis.  Specifically, retained bile acids and increased opiate activity have been thought to play a role.  More recently, lysophosphatidic acid (LPA) levels have been noted to be elevated in the serum of patients with cholestatic itch.  Injection of LPA into mice results in scratching activity.  LPA activity is a consequence of autotaxin.

Other important points:

  1. Rifampicin has been shown to reduce autotaxin levels in vivo.
  2. MARS and nasobiliary drainage do not directly drain autotaxin; their effects on autotaxin must result by eliminating another factor which stimulates autotaxin production.
  3. Autotaxin is likely to be a useful objective biological marker for pruritus and to evaluate potential novel treatments.
  4. Autotaxin elevation can occur in other noncholestatic inflammatory disease in which pruritus is not a feature; thus, the reasons for pruritus are likely multifactorial and not due to a simple causal role for autotaxin.

Related blog entries:

Challenges with primary sclerosing cholangitis | gutsandgrowth

BRIC, PFIC, and nasobiliary drainage | gutsandgrowth

Additional references:

  • -J Hepatol 2009; 51: 237-67.  EASL practice guidelines on mgt of cholestatic liver disease
  • -JPGN 2010; 51: 787.  Use of naltrexone in severe pruritus due to cholestasis: 1-2/kg/day. n=4.
  • -JPGN 2008; 46: 241.  Excellent review.  BRIC caused by FIC1 mutations (same as PFIC1).  Nasobiliary drainage of bile may be helpful.
  • -Hepatology 2007; 45: 666.  Use of sertraline (75-100mg; start with 25mg –in adults)
  •  -Clin Gastro & Hep 2007; 5:776 Use of zoloft for pruritus in cholestasis.
  • -Hepatology 2005; 42: 222. summary of cholestasis workshop
  • -JPGN 1999; 29: 442.  Rifampin treatment for cholestasis. 90% response, 40% complete response.  Extrahepatic cases c much better response.  No toxicity observed.
  • -Clin Liver Dis 2006; 10: 27-53.

Gene:                       Disorder (protein)

  1. ABCB11                     PFIC 2, BRIC 2 (BSEP)
  2. ABCB4                       PFIC 3, ICP (MDR3)
  3. CFTR                         CF (CFTR)
  4. ATP8B1                      PFIC1 -Byler’s (FIC1), BRIC, GFC -Greenland Familial
  5. CLDN1                       NISCH (Claudin 1) -neonatal sclerosing cholangitis/icthyosis VPS33B                     ARC syndrome (Vascular protein sorting 33) -arthrogryposis-   renal dysfn-cholestasis, low GGT
  6. AKR1D1                    BAS: Bile acid synthetic defect: neonatal cholestasis with giant cell hepatitis   (5Beta-reductase)
  7. HSD3B7                    BAS (C27-3Beta-HSD)
  8. CYP7BI                     BAS (CYP7BI)
  9. TJP2 (ZO-2)              FHC: Familial hypercholanemia (tight junction protein)
  10. BAAT                        FHC (BAAT)
  11. EPHX1                     FHC (epoxide hydrolase)
  12. JAG1                        Alagille (JAG1) JAG1 is transmembrance cell-surface protein important in   regulating cell fate during embryogenesis
  13. PKHD1                     ARPKD (fibrocystin -important in ciliary function and tubulogenesis)
  14. PRKCSH                  ADPLD (hepatocystin)
  15. ABCC2                     Dubin-Johnson syndrome (MRP2)
  16. CIRH1A                    NAIC -N Amer Indian childhood cirrhosis (Cirhin)

Ustekinumab for Crohn’s Disease

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Ustekinumab is emerging as an option for inflammatory bowel disease.  A study examining its effectiveness for TNF-refractory Crohn’s disease has been published (NEJM 2012; 367: 1519-28).

In this trial, members of CERTIFI (Crohn’s Evaluation of Response to Ustekinumab Anti-Interleukin-12/23 for Induction) from 153 centers in 12 countries assessed the efficacy of Ustekinumab in 526 adult patients.  The primary outcome was a clinical response (CDAI >100 point drop) at 6 weeks.

Ustekinumab (currently approved for plaque psoriasis) is a ‘fully human IgG1κ monoclonal antibody’ which blocks the activity of interleukin-12 (IL-12) and interleukin-23 (IL-23) by inhibiting receptors on T cells, natural killer cells, and antigen-presenting cells.  IL-12 and IL-23 have been implicated in the pathophysiology of Crohn’s disease.

This study of ustekinumab was a 36-week randomized, double-blind, placebo-controlled phase 2b trial.  The first 8 weeks were for induction.  After induction, based on response, patients were enrolled in a 28-week maintenance phase.  Initial dosing was 1, 3, or 6 mg/kg of intravenous ustekinumab or placebo.  Maintenance dose was 90 mg subcutaneously.

Patients were permitted to continue receiving stable doses of drugs.  However, entry requirements included a washout period for intravenous glucocorticoids (3 weeks), TNF antagonists (8 weeks), and natalizumab (12 months).

Results:

  • 36.6%, 34.1% and 39.7% of ustekinumab patients (1, 3, and 6 mg/kg respectively) responded at 6 weeks compared with 23.5% of placebo.  The difference was statistically significant for 6 mg/kg/dose.
  • Maintenance therapy (among responders) noted increased clinical remission with ustekinumab compared with placebo 41.7%  vs 27.4%.
  • Overall rates of infection were similar. Serious infections were noted in 6 patients receiving ustekinumab compared with 1 placebo-treated patient.  Infusion reactions were uncommon.
  • Patients who did not have a response to ustekinumab in the induction phase did not benefit from additional ustekinumab in the maintenance phase.

Overall, in this study, patients dosed at 6 mg/kg during induction were more likely to have a response but not more likely to have a remission.  Since all patients in this study had failed at least one TNF antagonist and 50% had failed at least two, the benefit of ustekinumab in other Crohn’s disease patients remains undefined.

Related blog entries:

CHOOSE TNF TRIAL | gutsandgrowth

Vedolizumab -another new IBD treatment | gutsandgrowth

Adding Methotrexate to anti-TNF therapy | gutsandgrowth

Targeted aspirin therapy to improve colorectal cancer survival

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A recent study shows that a specific subset of patients with colorectal cancer are most likely to benefit from aspirin therapy (NEJM 2012; 367: 1596-606).

This study used data from two prospective cohort studies, the Nurses’ Health Study (n=121,700) and the Health Professionals Follow-up Study (n=51,500).  Among these patients, data was analyzed from 964 in whom there was known information on the presence or absence of the PIK3CA mutation.  In total, only 161 of these 964 patients had mutations in PIK3CA; 66 of these took aspirin and 95 did not.

Mutations in PIK3CA affect the gene encoding phosphatidylinositol-4,5-bisphosphonate-3-kinase and occur in 15-20% of colorectal cancers.  Up-regulation of this gene enhances prostaglandin E2 synthesis and prostaglandin-endoperoxide synthase 2 (also known as cyclooxygenase-2) which results in the inhibition of apoptosis in colon-cancer cells. Due to this mechanism, the authors hypothesized that blocking this pathway with aspirin would have a beneficial outcome with regard to tumor molecular characteristics and patient outcomes.

Mutations in PIK3CA were detected with PCR and pyrosequencing after DNA extraction from paraffin-embedded tissues.

Among patients with mutated-PIK3CA colorectal cancers, regular use of aspirin after diagnosis was associated with better survival.  Hazard ratio for cancer-related death was 0.18 and overall death rate also was lower with hazard ratio of 0.54.  In patients without this mutation (wild-type PIK3CA), regular use of aspirin was not associated with a survival advantage; hazard ratio of cancer-specific survival was 0.96 and overall survival hazard ratio was 0.94.

While this study had data on a large number of other characteristics, including BRAF, KRAS, CIMP, LINE-1, and microsatellite instability, it lacked statistical power to examine many of these other modification effects.

These data, if confirmed, indicate a role for aspirin in colorectal cancer patients with PIK3CA mutations.

Related blog entries:

Microbial transfer for metabolic syndrome?

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Animal models have demonstrated an association between microbiota composition and obesity.  Now, a study shows that the transfer of intestinal microbiota from lean human donors to individuals with metabolic syndrome can improve insulin sensitivity (Gastroenterology 2012; 143: 913-16).

It is known that the small intestine has sensing mechanisms to improve insulin sensitivity via neuronal circuits and changes in microbe composition may be one of the stimuli for this mechanism.  Given the association of altered microbiota with obesity, the investigators divided 18 patients with metabolic syndrome to receive either an allogenic infusion (n=9) of gut microbiota or an autologus infusion (n=9) of gut microbiota.

All subjects underwent small bowel biopsies and then subsequently had lavage through a duodenal tube.  In the allogenic group, the infusate was derived from lean male donors (BMI <23 kg/m-squared).  Insulin sensitivity was measured before and 6 weeks after infusions.

Results:

  • Fecal microbiota of obese subjects was characterized by lower microbial diversity and higher amounts of certain microbes (eg. Bacteroidetes).
  • Peripheral insulin sensitivity improved after allogenic infusion with a median of 26.2 μmol/kg/min prior to 45.3 μmol/kg/min at the six-week measurement.  It was unchanged in those with the autologous infusion as noted in Figure 1.
  • Gut microbial diversity increased significantly after allogenic infusion 178 ± 62 –>234 ± 40 species.  It was essentially unchanged in the autologous group (from 184 ± 71 to 211 ± 50).  Heat maps (Figure 2) help illustrate the microbial changes in the subjects.
  • The authors conclude that butyrate derived from many of the increased bacterial group probably has a regulatory role in improving insulin sensitivity.  Butyrate can prevent translocation of endotoxic compounds derived from gut microbiota which can promote insulin resistance.

Perhaps in a few years, besides limiting the consumption of sugary beverages in places like NYC, beverages with “lean” microbes and or “lean” probiotics may become important.

Do we need clinical scores in pediatric pancreatitis?

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A retrospective study (2003-2007) confirms the limited utility of severity scores in pediatric pancreatitis (JPGN 2012: 55: 266-67). The authors collected data from 48 children; 13 were considered to have severe acute pancreatitis (AP).

Three clinical scores, Ranson, Glasgow modified, and DeBanto, were compared; in addition, the Balthazar computed tomography (BCT) severity index was examined.  Based on their cohort, the clinical scoring systems had a specificity of about 85% but a poor sensitivity of about 55% (53-62%).  The BCT had a sensitivity of 80% and a specificity of 86%. Though, to limit radiation exposure, ultrasonography is preferred over routine use of CT scanning for most pediatric patients.

These data indicate that it is not necessary to remember Ranson’s criteria (or to download a app for that).

More “Survivin” in Crohn’s disease

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Survivin is a member of the inhibitors of apoptosis family.  It helps regulate cell division and prevents cell death.  (Gastroenterology 2012; 143: 1017-26).  While survivin has been shown to be important in cancer, it appears to be important in inflammatory and autoimmune disorders.

In the referenced study, lamina propria T cells (LPT) were isolated from mucosal samples of patients with Crohn’s disease (CD), ulcerative colitis (UC), and controls.  Expression of survivin was assessed by immunohistochemistry, confocal microscopy, and immunoblotting.

LPTs from patients with Crohn’s disease had increased survivin levels; this was not seen in control patients or UC patients.  Furthermore, the investigators showed that the survivin (bound to heat shock protein) was resistant to proteasome degradation.

Implications of this study: 

Survivin may have crucial consequences for CD and other inflammatory/autoimmune diseases; cell proliferation and apoptosis alteration may be important in the pathogenesis of  in these disorders.

Two new drugs for obesity

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Undoubtedly, a safe, effective medication for obesity would be a pharmaceutical blockbuster.  The record so far on previous medications has been dismal.  Many have been abandoned due to safety concerns, including sibutramine (myocardial infarction and stroke) as well as dexfenfluramine/fenfluramine (valvulopathy).  Two new FDA-approved agents have shown promise but caution in their use will be needed (NEJM 2012; 367: 1577-79).  Neither agent has approval for pediatric usage.

Belviq (lorcaserin) is a selective agonist of the serotonin 5-HT-2C receptor and Qsymia (phentermine with topiramate) is a combination sympathomimetic amine (anorectic agent) with an antiepileptic drug.

In studies with lorcaserin, three studies (1-year placebo-controlled) have shown that the number of patients losing >5% of body weight was increased compared to placebo.  Mean percentage body weight loss with lorcaserin was -5.8% in first two studies and -4.5% in third study.  In contrast, placebo patients who received lifestyle counseling lost  -2.5% and -1.5% respectively.  Overall, up to 47% of patients receiving medication lost more than 5% body weight.

Potential safety concerns with lorcaserin:  initially there were concerns due to increased incidence of tumors in rats and possible valvulopathy (eg. mitral or aortic valve regurgitation).  However, the FDA has concluded that it is unlikely that these are likely to occur in humans.

With phentermine/topiramate, two placebo-controlled studies have shown an increase in patients losing >5% of body weight compared to placebo.  In the first study, the mean percentage change in body weight was -10.9% combination (dosage 15 mg/92 mg) compared with -1.6% for placebo.  In the second study, this dosage led to a -9.8% reduction compared with -1.2% in placebo patients. Overall, up to 70% of patients receiving medication lost more than 5% body weight.

With regard to safety, it is known that topiramate is teratogenic and increases the risk of orofacial cleft.  Due to this, approval for this combination requires a risk evaluation and mitigation strategy (REMS) which permits only specially-certified pharmacies to dispense along with formal training for prescribers. In addition, this combination has been associated with mildly increased heart rate. Due to favorable changes in blood pressure, the FDA concluded that this medication had a good benefit-risk balance.  But, the manufacturer recommends against it use in patients with cardiac issues or cerebrovascular disease.

With both new medications, other safety concerns include the risk of increased psychiatric effects.  In addition, specific recommendations include the following:

  • Only recommended in adults with BMI ≥30 or adults with BMI ≥27 with at least one weight-related comorbidity
  • With both medications, if weight loss not adequate after 12 weeks then discontinue medication.  With lorcaserin, if weight loss is not ≥5%, then discontinue.  With phentermine/topiramate, if weight loss is not ≥3% at 12 weeks (with 7.5 mg/46 mg), consider dosage increase and/or discontinuation.

Related blog entries:

Can NALFD be improved with bile acid sequestration?

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Probably not (Hepatology 2012; 56: 922-32).

Because bile acid sequestrants like colesevelam (& cholestyramine) lower plasma low density lipoprotein (LDL) levels and can improve glycemic control, a recent study tested the hypothesis that this would result in improvement in patients with biopsy-proven nonalcoholic steatohepatitis (NASH).

Methods: 50 patients were randomly assigned to either colesevelam 3.75 g/d or placebo for 24 weeks.  All patients had a liver biopsy within 6 months as a baseline study.  The primary outcome was liver fat as measured by a MRI technique (proton-density fat-fraction or PDFF) and by MR spectroscopy. At the start and conclusion of the study patients had biochemical assays, MRI-PDFF & MR spectroscopy; also, patients had a liver biopsy at completion of study.

Results: The colesevelam group had increased fat at the conclusion of the study period by a mean difference of 5.6% with PDFF and 4.9% with MR spectroscopy, both compared with placebo group.  In addition, liver biopsy did not detect any effect of treatment.  Looking at the biochemical indices, there was also a trend of increased transaminases in the treatment group compared to the control group (Table 3 in study).

Conclusions: The authors indicate that the increased fat may be due to a compensatory increase in bile acid synthesis.  Also, as the changes in fat were only detected on MRI, future NASH studies may benefit from this technique as well.

Related blog entries:

NAFLD Guidelines 2012 | gutsandgrowth

Pediatric NAFLD Position Paper | gutsandgrowth