Growth hormone is required for children to realize their full potential to grow taller. Those children who are unable to make normal amount of growth hormone do not grow well. Fortunately, daily growth hormone injections are an available therapy and robustly restore growth in these children. More rarely, some children can make growth hormone but can not respond to it properly due to various genetic reasons. One such reason is mutation of a gene termed PAPPA2. This gene produces a protein required for growth hormone to work. Specifically, the PAPPA2 protein liberates IGF-1 — the major growth hormone induced growth factor — to allow it to promote growth. Persons who lack a proper PAPPA2 gene thus do not grow well. An active question in the field regards whether giving IGF-1 supplements might overcome this issue and promote growth in children with this condition. Dr. Eirene Alexandrou from our Division was part of a team that studied this question and have now published their findings. Their results suggest that indeed IGF-1 can improve growth in children with genetic mutations in PAPPA2, but that the therapy may not completely normalize growth. Because IGF-1 therapy can have side effects, they suggest weighing pros and cons with each family when considering treatment. Their findings have been published in the journal Hormone Research in Paediatrics. The abstract has been indexed in Pubmed and can be found here.
Persons with cystic fibrosis typically have an imbalance in their fatty acid levels. A prominent aspect of this imbalance is a deficiency of linoleic acid, which is one of the so-called essential fatty acids. Despite decades of research, the mechanisms of the imbalance are not fully understood. To better understand this fatty acid imbalance, a group of researchers at the University of Iowa, Kansas State University, and the Karolinska Institutet in Stockholm Sweden worked together to study pigs and ferret with cystic fibrosis. The results showed that the imbalance exists at birth even before first feeding. This result argues strongly against one of the leading prior hypotheses which was that the imbalance might stem from the nutrient malabsorption that occurs in cystic fibrosis. Instead, the results suggest that several molecular mechanisms might be responsible for the imbalance, including excess metabolism of arachidonic acid, oxidative isomerization of unsaturated fatty acids, and/or biliary loss of phospholipids containing unsaturated fatty acids. The senior author of the resulting manuscript describing the findings was Dr. Norris from our Division. The work can be found published in the journal Clinical Science (link).
Cystic fibrosis is a genetic disease that causes dysfunction in multiple systems, but especially in the lungs which progressively deteriorate. The past few years have seen massive progress in the medical treatment of cystic fibrosis. Drugs have come to market that correct the basic molecular defects that cause cystic fibrosis. These drugs are classified as “highly effective modulator therapies”. These therapies must be tailored to each person, by matching to the different mutations that cause cystic fibrosis. In 2019, a blend of three modulators was approved for treatment of the most common form of cystic fibrosis involving the “F508del” mutation. This therapy combines elexacaftor, tezacaftor, and ivacaftor (“ETI”). This therapy dramatically improves lung dysfunction in persons with cystic fibrosis due to F508del mutation. Persons with cystic fibrosis are at very high risk to develop diabetes. For example, those who have only have F508del mutation have an over 80% chance of developing diabetes by middle age. It is currently not known if ETI-therapy for cystic fibrosis will impact diabetes risk. To address this knowledge gap, investigators from 5 institutions conducted a study of twenty persons with cystic fibrosis. Each person underwent an oral glucose tolerance test before and roughly 10 months after starting ETI-therapy. Interestingly, there was not a significant change in glucose levels after starting ETI. However, C-peptide levels increased with ETI therapy, consistent increased insulin secretion. Accordingly, an insulin resistance index significantly increased as did body mass index. Taken together, these results suggest that ETI therapy produces a degree of insulin resistance, likely related to an increase in body mass index. The longer term impact of ETI and related therapies on diabetes risk and body weight will need careful ongoing study. The faculty investigators involved in the study from our division were Dr. Larson Ode and Dr. Norris. The publication describing the study and results can be found at this Pubmed link.
Therapies for cystic fibrosis are becoming far more effective, improving health and extending life for those with this genetic disease. Decades ago, most persons with cystic fibrosis often died before reaching reproductive capacity. Thankfully, this is no longer the case. For this reason, counseling about reproduction is thus more important than ever in this population. However, little is known about how often health care teams provide reproductive counseling for these patients. This is even more important, because pregnancy can have a highly adverse impact on health in those with cystic fibrosis. To better understand the issue, Dr. Katie Larson Ode and colleagues have reviewed medical charts of persons with cystic fibrosis. They found that most patients did not receive documented reproductive counseling. This highlights a potential gap in care that could be readily addressed. The results from the study have now been published in the journal Pediatric Pulmonology, and indexed in PubMed at this link.
Over the past decade, evidence has emerged indicating that high blood sugars in type 1 diabetes cause adverse brain changes in children. The adverse changes include abnormal brain structural alterations and reduced functioning on some cognitive tests. Over the past few years, hybrid closed-loop insulin pumps have become commercially available. These devices combine a continuous glucose monitor (CGM) with an insulin pump that is controlled by an algorithm that uses the CGM data to inform insulin delivery. The hybrid closed-loop insulin pumps aim to keep blood sugar in the low 100s (mg/dL). These systems can often improve average blood sugars and reduce the severity and frequency of low and high blood sugars. It is thus natural to ask whether the improved blood sugar control offered by a hybrid closed-loop insulin pumps might reduce the adverse brain effects of type 1 diabetes in children. Dr. Mike Tansey and Dr. Eva Tsalikian from our Division were among a small group of diabetes physicians across the United States who designed such a study to answer this very question. The initial results from the study were just published in the prestigious journal Nature Communications (click for PubMed link). Their randomized clinical study involved 42 adolescents with type 1 diabetes who were randomized to a hybrid closed-loop insulin pump versus conventional therapy. They were studied 6 months later, undergoing a brain MRI and cognitive testing. Although this study was considered a pilot trial, the results showed significantly less adverse impacts in those randomized to the hybrid closed-loop insulin pumps. The hybrid closed-loop insulin pump group performed better on a cognitive test of perceptual reasoning and had fewer abnormal structural brain changes. These results add to the growing evidence showing that excessive hyperglycemia is damaging to the developing brain during childhood. Thus study shows the important positive impact that hybrid closed-loop insulin pumps can make in improving blood sugar levels and long term outcomes in children with diabetes.
There is a drastic need to devise better approaches to prevent, treat, and ultimately reverse diabetes. Essential to any progress is the constant training of skilled cohorts of research investigators. To this end, since 2017, the University of Iowa has nurtured a Diabetes Research Training Program. The Program supports mentored postdoctoral training focused on various diabetes research topics. Six postdoctoral trainees are supported at any given time, typically for two years each. To date, 19 postdoctoral trainees have been support by this Program, including pediatric endocrine faculty Dr. Pinnaro while she was a fellow. The Program was conceived by adult endocrinologist Dr. Dale Abel and pediatric endocrinologist Dr. Norris. Based on a proposal detailing their vision, they received a 5-year “T32” grant from the NIH to fund the program 2017-2022. During this time, the Program has been a resounding success, with most trainees having progressed onward in their research careers in academia or related private industry. Based on the strengths of the initial trainees, their research, and career progress, last year Drs. Norris and Abel wrote a renewed 5-year proposal for ongoing training. Today, we are pleased to announce that the proposal was viewed very favorably and that an additional 5 years of grant support will be provided by the NIH (you can view a summary of the grant at this link). Future or existing pediatric endocrine fellows who are interested a career focused on diabetes research can benefit from this program and are encouraged to contact Dr. Norris to discuss the application process.
For reasons that are not well understood, persons with cystic fibrosis are at very high risk to develop diabetes. A major factor in this risk is poor secretion of insulin from beta-cells. A research team at the University of Iowa has now published findings that may have identified one of the root causes. The team found exceptionally high levels of reactive oxygen species in pancreas with cystic fibrosis. Furthermore, the islets isolated from cystic fibrosis pancreases exhibited increased production of reactive oxygen species and impaired secretion of insulin. However, two different approaches aimed at reducing or neutralizing excess reactive oxygen species production failed to improve insulin secretion. Nonetheless, the findings highlight what might be an important contributor to poor insulin secretion in persons with cystic fibrosis. From our division, Dr. Andrew Norris contributed to the research and publication. The paper can be found at this DOI link and a full text version can be found at this PubMed Central link.
Each June, the American Diabetes Association hosts its annual scientific meeting. This meeting is the world’s largest and most important gathering focused on diabetes research, attracting over 10,000 attendees who come from across the world to hear the latest cutting edge research. This year, the University of Iowa was featured in a short video film shown at the meeting. The video focused on how the Fraternal Order of Eagles Diabetes Research Center (FOE-DRC) is advancing diabetes research . The FOE-DRC was created in 2008 when the Fraternal Order of Eagles pledged $25 million to establish a diabetes research center at the University of Iowa. With this gift, the FOE-DRC has grown to include over 100 faculty researchers from across the University. Collectively, these faculty conduct over $30 million of NIH-funded research annually. Several members of our Division are faculty in the FOE-DRC: Drs. Curtis, Larson Ode, Norris, Pinnaro, Tansey, and Tsalikian. Earlier this year, the American Diabetes Association requested that investigators at the University of Iowa help create a short video highlighting the work of the FOE-DRC. The video is now available on youtube (link to video here). The video highlights work by two members of our Division: Dr. Larson Ode and Dr. Norris, as well as several colleagues in the Division of (Adult) Metabolism and Diabetes and in the FOE-DRC.
Turner syndrome affects over 70,000 women in the United States. Turner syndrome is caused by loss genetic material from one X chromosome in a process that happens long before birth. Turner syndrome increases the risk of a variety of physical and medical changes such as shorter stature, subtle changes in facial structure, delayed puberty, congenital heart disease, and frequent ear infections. It has more recently been recognized that Turner syndrome also increases the risk of anxiety and depression. To better address the situation, Dr. Eirene Alexandrou recently developed an approach by which medical providers can screen persons with Turner syndrome using a simple questionnaire. She found that a high proportion, over half, of women with Turner syndrome had elevated anxiety levels. The results of Dr. Alexandrou’s study have been published this month in the journal “Hormone Research in Paediatrics” after peer review. The abstract of the work can be found on Pubmed (link). The results highlight the importance of multidisciplinary specialty clinics for persons with Turner syndrome, such as the clinic here led by Dr. Alexandrou and Dr. Pinnaro.
Type 2 diabetes affects over 35 million Americans and is a leading cause of disability, expense, and mortality. Type 2 diabetes occurs worldwide and some countries have rates up to roughly three times higher than in the US. Type 2 diabetes rates are climbing, in part because there are not optimal therapies and preventative strategies. Dr. Norris has contributed to a team that has identified a novel molecular target to treat type 2 diabetes. The new findings have now been published in the scientific journal Nature Communications (link). The new target is a protein named SWELL1. It is a chloride transport protein and is involved in beta-cell and adipose tissue functions. Interestingly, certain small molecules that inhibit SWELL1 both improve insulin sensitivity and increase beta-cell function. This combination of effects potently improved blood sugar levels in mice, indicating that these types of SWELL1 inhibitors may be a very effective means to treat and/or prevent type 2 diabetes.