Alexander Bondoc, MD

Bondoc is an investigator and pediatric surgeon in the Division of Pediatric General and Thoracic Surgery. Bondoc’s laboratory investigates novel molecular pathways important in the development of aggressive hepatoblastoma (HB), the most common primary liver tumor in children. The lab is currently investigating the role of glypican 3 (GPC3) and enhancer of zeste 2 (EZH2) in development of HB. These investigations may be pivotal in the discovery of novel therapies to treat patients, the importance of GPC3 protein cleavage in HB tumor growth and proliferation, and understanding the specific mechanism of EZH2 in HB. His lab utilizes single-cell sequencing technology to explore tumor heterogeneity and define the characteristics of tumor driver cell clusters. Bondoc’s laboratory generates patient-derived xenografts (PDX) of human HB and hepatocellular carcinoma (HCC) to augment understanding of the genotypic and phenotypic behavior of pediatric liver tumors. Used as an in-vivo method for pre-clinical studies, murine models are also applicable for therapeutic testing and drug development.

Gregory Tiao, MD

Tiao is the head of the Division of Pediatric General and Thoracic Surgery and surgical director of liver transplantation. Tiao is also a member of the Liver Tumor Program and the Children’s Oncology Group Liver Tumor Committee. The Tiao lab, including Rajamouli Pasula, PhD, research assistants Bryan Donnelly and Haley Temple, along with surgical resident, Stephen Hartman, MD, continues work on the pathogenesis of biliary atresia through an ongoing R01 grant. Specifically, this grant focuses on how the amino acid sequence “SRL” (445-447), found within the VP4 protein of certain strains of rotavirus, utilizes a unique receptor on the surface of cholangiocytes and dendritic cells governing intracellular trafficking of the virus resulting in activation of an innate immune response.

Mechanistic studies utilizing multiple novel single amino acid mutant strains of Rhesus rotavirus (RRV) corresponding to known cellular receptor binding sites (Heat shock cognate protein 70 (Hsc70), sialic acid, and integrin alpha2beta1) demonstrated high mobility group box-1 protein (HMGB1) release from cholangiocytes was dependent on RRV VP4 protein’s ability to bind to Hsc70 on the surface of cells. Cholangiocytes infected with other viruses isolated from biliary atresia patients (Reovirus, CMV) induced HMGB1 release illustrating a potential common pathway for disease initiation. A recently published manuscript in Hepatology Communications entitled “Rhesus Rotavirus receptor binding site affects HMGB1 release, altering the pathogenesis of experimental biliary atresia” reported these findings.

Researchers evaluated the role of transcription factor Tbx21 (T-bet) gene in the progression of biliary atresia. Newborn T-bet knockout (KO) pups infected with Rhesus rotavirus resulted in a decreased Th1 inflammatory chemokine/cytokine profile when compared to infected wild-type mice. Analysis of the mononuclear cell profile from T-bet KO mice revealed both a significant decrease in the total number of CD3, CD4 and CD8 T cells and their effector molecules granzyme A, perforin, and FasL resulting in the extrahepatic bile ducts of these T-bet KO mice remaining patent post-infection. A manuscript published in Cells entitled “T-bet deficiency attenuates bile duct injury in experimental biliary atresia.” reported these findings.

Tiao and James Geller, MD, are study co-chairs on the Children’s Oncology Group (COG) Pediatric Hepatic Malignancy International Therapeutic Trial (PHITT). The expectation is for this trial to run for the next five years and accrue 500 patients in North America with 1,200 participants worldwide.

Jason Frischer, MD

Frischer is the director of the Colorectal Center and associate director of the Division of Pediatric General and Thoracic Surgery. Frischer is also director of the Extracorporeal Membrane Oxygenation (ECMO) Program.

Frischer published eight peer-reviewed articles this past year and was the guest editor for the April 2022 issue on Hirschsprung's disease in the Seminars in Pediatric Surgery. This 12-chapter issue focused on the most up-to-date issues associated with Hirschsprung disease. He co-authored two manuscripts within this issue, including "Surgical History of Hirschsprung Disease" and "Hirschsprung disease in low- and middle-income countries."

This past year, he also published three multi-institutional collaborative articles on pediatric colorectal diseases as part of the PCPLC. He also published two papers on ECMO; one describing the cost of ECMO and another focused on anticoagulation. Finally, he published a cumulative paper describing bowel management outcomes entitled, "Prospective quality of life outcomes in pediatric fecal incontinence following bowel management." This paper was a collaborative work with the Colorectal Center and multiple psychologists demonstrating our center's results using a quality of life tool validated by our team.

Frischer and the Colorectal Center team studied the impact of radiology imaging on the clinical treatment plans for Bowel Management Program patients. The team captured and compiled data from every cohort since January 2021. Providers develop a plan based on medical history, clinical symptoms, daily bowel movement logs, medication, enemas, diet, and more independent from and prior to viewing radiology imaging. In doing so, the team is identifying where there are opportunities to reduce and individualize radiology imaging.

Providers are identifying a subset of good candidates and offering them a low-radiation alternative to the traditional program with fewer x-rays. With the traditional program involving daily abdominal x-rays over the course of six days, and often a water-soluble contrast enema, the appointments, cost, radiation exposure, and demands of real-time imaging results can decrease accessibility to the expertise of the Colorectal Center and decrease the ability to deliver care remotely. Preliminary results show promising signs for research-validated program innovations. Patients and families involved in the low-radiation program receive evaluations at specified intervals over time using severity score and quality of life measurements to ensure outcomes are comparably high.

Frischer and the colorectal team are preparing to host the 2022 PCPLC International Colorectal Course and Symposium, which hosts approximately 400 leaders and trainees focused on pediatric colorectal surgery.

Jose Peiro, MD, PhD

A research team led by Peiro, the director of endoscopic fetal surgery at the Fetal Care Center, continues to investigate the basic mechanisms of pediatric and fetal surgical congenital malformations, focusing especially upon fetal myelomeningocele (MMC), congenital diaphragmatic hernia (CDH), fetal hydrocephalus, and gastroschisis.

The focus of MMC is to improve the fetoscopic approach for intrauterine repair by evaluating different patches and sealants in large animal models in collaboration with biomedical engineers at the University of Cincinnati with professor Chia-Ying Lin's lab and then translating these techniques for use in the human fetus. Peiro and Lin recently received an award from R01 to support their research using an innovative "smart patch" for the fetoscopic procedure to repair MMC using a sheep model. In addition, a clinical trial is comparing fetoscopic MMC repair in humans versus the standardized open fetal surgery approach. An MRI prenatal assessment is in process to analyze the early anatomic improvements after fetal surgery for MMC. Researchers are determining the mechanistic processes and pathways activated in the neuro-inflammation and neurodegeneration that appear in open neural tube defects by means of rodent and sheep models. The team is studying ways to use neural progenitor cells collected from the cerebrospinal and amniotic fluid of MMC patients as a potential form of neural regeneration (cell therapy). In collaboration with Aimen Shaaban's lab at the Ann & Robert H. Lurie Children's Hospital in Chicago, they use a mouse model of neural tube defects to investigate how maternal immune status can influence on incidence of congenital malformations.

Evaluating Fetal Surgery to Support Lung Development

The Peiro lab continues to study animal models that indicate early fetal tracheal occlusion may induce faster and better fetal lung growth. Recently, they opened a new avenue of research by determining the metabolomic energetic cellular failure in the compressed fetal lung. They described comparison of a novel surgically-induced CDH model in rats with gene-expression to the teratogen nitrofen-induced CDH model in a collaborative study with Jeffrey Whitsett, MD, and his research group. This group uses rodents to determine a new radiologic prenatal and postnatal biomarker by 3D lung assessment for better prognosis of pulmonary hypertension. In collaboration with Brian Varisco, MD, and his lab, the Peiro lab is investigating molecular pathways involvement in lung growth after tracheal occlusion by proteomics in rabbit and sheep models. Moreover, they continue to clinically offer fetoscopic tracheal occlusion in human fetuses with severe CDH by detachable balloon insertion. This work will contribute to a new multi-center future trial.

Innovative Neuro-Endoscopic Prenatal Surgery for Congenital Obstructive Hydrocephalus

In the last eight years, Peiro's lab worked hard to assess a very innovative prenatal surgery to treat congenital hydrocephalus by fetal endoscopic third ventriculostomy (fETV) in large animal models as a bridge to implement this therapy in human clinic soon. They developed a novel model to generate severe obstructive hydrocephalus in fetal lambs by injecting a polymer in the cisterna magna by trans-uterine approach at mid-gestation. With this model they were able to make feasible endoscopic exploration of the enlarged lateral ventricles and create a third ventricular floor ostomy or opening to re-circulate the cerebrospinal fluid and decompress and preserve the fragile brain tissue in development. Now, they are working on demonstrating the cellular and molecular positive effects of this prenatal therapy.

Neuroenteric and Lymphatic Disorders Related to Gastroschisis

In gastroschisis, researchers are analyzing the neurodegenerative and lymphatic anomalies associated with fetal gastroschisis, and their implication with intestinal hypomotility and malabsorption in the rat and fetal rabbit model. They are studying the origin and presence of intrauterine growth restriction in these fetuses with gastroschisis in collaboration with Mounira Habli, MD, and looking for new prenatal strategies and therapies to decrease the intestinal edema and inflammation.

Meera Kotagal, MD, MPH

Kotagal is a pediatric surgeon in the Division of Pediatric General and Thoracic Surgery and director of the Surgical Equity Research Fellowship and director for Pediatric Trauma Services. Kotagal's interest is in variation in care and outcomes and how we can reduce the associated inequities. Her research focuses on disparities in injury-related morbidity and mortality and interventions used to close that gap.

Through funding from a Place Outcomes Research Award, Kotagal is examining the social determinants of health at a neighborhood level that underlie and drive pediatric injury in the Cincinnati region. The work will help us understand the broader contextual factors driving who gets injured and how severe those injuries are.

Initial analysis reveals that children from higher deprivation neighborhoods, who are disproportionately Black and publicly insured, experience a higher burden of interpersonal violence-related admissions. Future research will focus on initiatives to engage community members to identify neighborhood-specific injury prevention efforts.

Participation in different multi-center studies examined the association of pediatric injuries and the Covid-19 pandemic. Of note, there was an increase in non-accidental trauma in African American and older children. Findings also showed an association between the pandemic and increased pediatric firearm injuries above expected rates based on historical patterns.

Michael Helmrath, MD

Helmrath focuses his career on complex gastrointestinal diseases. He actively leads multidisciplinary clinical, translational and basic science programs. He currently serves as the director of Surgical Research for Cincinnati Children’s. Helmrath oversees extramural, translational and basic science studies focused on intestinal failure, obesity and type 2 diabetes, esophageal atresia, Hirschprung’s disease and cystic fibrosis. His basic science laboratory focuses specifically on the role of intestinal stem cells in small intestinal physiology. Multiple NIH awards since 2002 are continuously funding his work. His U01 award, U01DK103117, aims to lead to a deeper understanding of regional influence within the intestinal stem cell populations that may contribute to physiological and disease-specific differences commonly seen between the proximal and distal intestine. As part of the Intestinal Stem Cell Consortium he keeps actively involved in the intestinal stem cell field. His long-term research goal is to establish translational therapies for the management of patients with complex gastrointestinal diseases.

Nikolai Timchenko, PhD

Timchenko is a professor in the Division of Pediatric General and Thoracic Surgery at Cincinnati Children's and UC Department of Surgery. He is also head of Liver Tumor Biology for the Liver Tumor Program. His lab investigates mechanisms of hepatoblastoma (HBL), hepatocellular carcinoma (HCC), and mechanisms of non-alcoholic fatty liver disease (NAFLD).

Liver Cancer: The origin of liver cancer is under intensive investigation; however, researchers do not know a great deal about tumor-originating cell types and mechanisms that initiate aggressive pediatric liver cancer. Timchenko's lab generated five unique animal models with accelerated or inhibited liver cancer after treatments with certain carcinogens. Investigations of molecular pathways in these animal models showed that de-differentiation of hepatocytes into stem-like cells is the origin of hepatocellular carcinoma. In collaboration with Tiao and Bondoc within the division, Geller, from the Division of Oncology, and other members of the Liver Tumor Program, Timchenko analyzed a large cohort of liver samples from patients with HBL discovering molecular basis for two types of HBL. He found that classic (mild) HBL results from a failure of hepatic stem cells to differentiate into hepatocytes and that there is an association with this failure with the activation of FXR-Gankyrin axis. Timchenko recently published two papers which found that inhibition of Gankyrin by small molecule cjoc42 inhibits proliferation of cancer cells and increases the efficiency of drugs used for treatments of HBL patients.

During the last eight years, Timchenko's lab collected and investigated specimens from patients with pediatric liver cancers using procedures that prevent the loss of protein modifications and degradation. This approach allowed examination of critical pathways in liver cancer previously missed due to insufficient protection during the collection of samples. The most important discovery with these HBL tumor samples is the identification of human genomic regions that activate multiple oncogenes in pediatric liver cancer. These DNA regions are cancer-enhancer genomic regions or aggressive liver cancer domains (CEGRs/ALCDs). Timchenko's recent paper in Hepatology showed that, in aggressive HBL, the ph-S6-p53-PARP1 complexes activate CEGRs/ALCDs-containing oncogenes. He found that inhibition of PARP1 activity in patient-derived xenografts (PDXs) inhibits tumor growth. Search of the giant human DNA-Seq datasets (over 11,000 ChIP-Seq datasets) identified a β-catenin pathway that might activate CEGRs/ALCDs-containing oncogenes via direct binding of β-catenin-TCF4 complexes to CEGRs/ALCDs-dependent oncogenes. Timchenko is currently investigating if activation of β-catenin-TCF4-CEGRs/ALCDs pathway occurs in aggressive HBL and contributes to the aggressive features of HBL including lung metastases.

Timchenko is also working with epigenetic regulation of pediatric liver cancer. De-differentiation of hepatocytes into cancer cells is a first step of development of liver cancer. Timchenko recently published a paper showing the de-differentiation of hepatocytes involves repression of markers of hepatocytes and the increase of liver proliferation. Analyses of a fresh bio-bank of specimens from HBL patients showed that a significant portion of the HBL patients have increased levels of an oncogenic de-ph-S190-C/EBPα, SP5, and HDAC1 compared to amounts of these proteins in adjacent regions. Timchenko found creation of oncogenic de-ph-S190-C/EBPα in aggressive HBL by PP2A phosphatase, which increased within the nucleus and de-phosphorylates C/EBPα at Ser190. C/EBPα-HDAC1 and Sp5-HDAC1 complexes are abundant in hepatocytes which de-differentiate into cancer cells. Studies in HBL cells revealed that C/EBPα-HDAC1 and Sp5-HDAC1 complexes reduce markers of hepatocytes and p21 via repression of their promoters. Pharmacological inhibition of C/EBPα-HDAC1 and Sp5-HDAC1 complexes by SAHA and siRNA-mediated inhibition of HDAC1 increases expression of hepatocyte markers, p21, and inhibits proliferation of cancer cells.

Timchenko's lab showed that development of another liver cancer, fibrolamellar carcinoma (FLC) also involves the activation of CEGRs/ALCDs oncogenes. The underlying molecular mechanisms associate with FLC-specific mutation that generates fusion oncoprotein DNAJB1-PKAc. Timchenko found that DNAJB1-PKAc phosphorylates β-catenin at Ser675 leading to increase of β-catenin-TCF4 complexes and to activation of CEGRs/ALCDs containing collagens and oncogenes. The recent Timchenko's paper in Hepatology Communications demonstrated that the reduction of this axis by inhibitor of beta-catenin PRI-724 inhibits Fibrolamellar cancer in FLC organoids through a block of activation of fibrotic genes and oncogenes.

NAFLD: Investigations of NAFLD by Timchenko's lab resulted in discovering a triggering event that causes NAFLD. This event is the elevation of cdk4 and subsequent stimulation of a cascade of pathways that lead to NAFLD. Timchenko found the inhibition of cdk4 prevents / reverses early steps of NAFLD in animal models. Recent investigations by Timchenko's lab reveal that cdk4 inhibitors also correct age-associated steatosis and many other age-related liver disorders. Since the FDA approved the use of cdk4 inhibitors, and they are in clinical trials for liver cancer, it is possible to initiate clinical trials for NAFLD with these drugs. These discoveries received extensive media coverage. Since cdk4 is a strong promoter of liver proliferation, Timchenko's lab investigated the role of proliferation in NAFLD using two animal models with inhibited and accelerated liver proliferation. These studies found that liver proliferation, but not steatosis, is an essential driver of high fat-mediated fibrosis. Since obesity-associated NAFLD represents the most common cause of pediatric liver fatty disease, the ongoing studies in Timchenko's lab focus on the role of liver proliferation in pediatric fatty liver disease and mechanisms of this disease. Particularly, Timchenko found that epigenetic activation of C/EBPalpha is a key event in development of obese-pregnancy-associated liver disorders in children. Genetic mutation of this pathway in mouse models blocks development of obese-pregnancy-associated NAFL and NASH.

Soona Shin, PhD

Shin is a member of the Liver Tumor Program. Her research aims to decipher the molecular and cellular mechanism of childhood liver cancer with a focus on fibrolamellar carcinoma and to investigate the role of facultative postnatal hepatic progenitor cells in liver disease. The Shin lab employs molecular genetic approaches to test this hypothesis and collaborates with Timchenko and Bondoc to discover novel strategies for preventing and treating liver cancer.

Todd Jenkins, PhD

Jenkins is an associate professor in the Division of Pediatric General and Thoracic Surgery and director of the data coordinating center for Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS). His research focuses on obesity and surgical outcomes. He recently received a UM1 award from the National Institutes of Health, NIDDK, titled “Continuation of Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS), Biostatistics Research Center” in collaboration with Changchun Xie, PhD, professor of biostatistics in the Department of Environmental Health at the University of Cincinnati. The New England Journal of Medicine (May 2019) recently published the latest findings from the Teen-LABS study. He serves as co-principal investigator with Meg Zeller, PhD, from the Division of Behavioral Medicine and Clinical Psychology, on the NIH-NIDDK (R01) funded project, “Adolescent Bariatric Surgery: Weight and Psychosocial Risk in Young Adulthood.”