Publications by authors named "Stefanie Peters"

10 Publications

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The Impact of Nonpharmacological Interventions on Patient Experience, Opioid Use, and Health Care Utilization in Adult Cardiac Surgery Patients: Protocol for a Mixed Methods Study.

JMIR Res Protoc 2021 Feb 16;10(2):e21350. Epub 2021 Feb 16.

Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, United States.

Background: Despite pharmacological treatments, patients undergoing cardiac surgery experience severe anxiety and pain, which adversely affect outcomes. Previous work examining pediatric and nonsurgical adult patients has documented the effectiveness of inexpensive, nonpharmacological techniques to reduce anxiety and pain as well as health care costs and length of hospitalization. However, the impact of nonpharmacological interventions administered by a dedicated comfort coach has not been evaluated in an adult surgical setting.

Objective: This trial aims to assess whether nonpharmacological interventions administered by a trained comfort coach affect patient experience, opioid use, and health care utilization compared with usual care in adult cardiac surgery patients. This study has 3 specific aims: assess the effect of a comfort coach on patient experience, measure differences in inpatient and outpatient opioid use and postoperative health care utilization, and qualitatively evaluate the comfort coach intervention.

Methods: To address these aims, we will perform a prospective, randomized controlled trial of 154 adult cardiac surgery patients at Michigan Medicine. Opioid-naive patients undergoing first-time, elective cardiac surgery via sternotomy will be randomized to undergo targeted interventions from a comfort coach (intervention) versus usual care (control). The individualized comfort coach interventions will be administered at 6 points: preoperative outpatient clinic, preoperative care unit on the day of surgery, extubation, chest tube removal, hospital discharge, and 30-day clinic follow-up. To address aim 1, we will examine the effect of a comfort coach on perioperative anxiety, self-reported pain, functional status, and patient satisfaction through validated surveys administered at preoperative outpatient clinic, discharge, 30-day follow-up, and 90-day follow-up. For aim 2, we will record inpatient opioid use and collect postdischarge opioid use and pain-related outcomes through an 11-item questionnaire administered at the 30-day follow-up. Hospital length of stay, readmission, number of days in an extended care facility, emergency room, urgent care, and an unplanned doctor's office visit will be recorded as the primary composite endpoint defined as total days spent at home within the first 30 days after surgery. For aim 3, we will perform semistructured interviews with patients in the intervention arm to understand the comfort coach intervention through a thematic analysis.

Results: This trial, funded by Blue Cross Blue Shield of Michigan Foundation in 2019, is presently enrolling patients with anticipated manuscript submissions from our primary aims targeted for the end of 2020.

Conclusions: Data generated from this mixed methods study will highlight effective nonpharmacological techniques and support a multidisciplinary approach to perioperative care during the adult cardiac surgery patient experience. This study's findings may serve as the foundation for a subsequent multicenter trial and broader dissemination of these techniques to other types of surgery.

Trial Registration: ClinicalTrials.gov NCT04051021; https://clinicaltrials.gov/ct2/show/NCT04051021.

International Registered Report Identifier (irrid): DERR1-10.2196/21350.
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http://dx.doi.org/10.2196/21350DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7925147PMC
February 2021

Chronic linaclotide treatment reduces colitis-induced neuroplasticity and reverses persistent bladder dysfunction.

JCI Insight 2018 10 4;3(19). Epub 2018 Oct 4.

Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia.

Irritable bowel syndrome (IBS) patients suffer from chronic abdominal pain and extraintestinal comorbidities, including overactive bladder (OAB) and interstitial cystitis/painful bladder syndrome (IC-PBS). Mechanistic understanding of the cause and time course of these comorbid symptoms is lacking, as are clinical treatments. Here, we report that colitis triggers hypersensitivity of colonic afferents, neuroplasticity of spinal cord circuits, and chronic abdominal pain, which persists after inflammation. Subsequently, and in the absence of bladder pathology, colonic hypersensitivity induces persistent hypersensitivity of bladder afferent pathways, resulting in bladder-voiding dysfunction, indicative of OAB/IC-PBS. Daily administration of linaclotide, a guanylate cyclase-C (GC-C) agonist that is restricted to and acts within the gastrointestinal tract, reverses colonic afferent hypersensitivity, reverses neuroplasticity-induced alterations in spinal circuitry, and alleviates chronic abdominal pain in mice. Intriguingly, daily linaclotide administration also reverses persistent bladder afferent hypersensitivity to mechanical and chemical stimuli and restores normal bladder voiding. Linaclotide itself does not inhibit bladder afferents, rather normalization of bladder function by daily linaclotide treatment occurs via indirect inhibition of bladder afferents via reduced nociceptive signaling from the colon. These data support the concepts that cross-organ sensitization underlies the development and maintenance of visceral comorbidities, while pharmaceutical treatments that inhibit colonic afferents may also improve urological symptoms through common sensory pathways.
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http://dx.doi.org/10.1172/jci.insight.121841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6237488PMC
October 2018

cGMP Imaging in Brain Slices Reveals Brain Region-Specific Activity of NO-Sensitive Guanylyl Cyclases (NO-GCs) and NO-GC Stimulators.

Int J Mol Sci 2018 Aug 7;19(8). Epub 2018 Aug 7.

Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany.

Impaired NO-cGMP signaling has been linked to several neurological disorders. NO-sensitive guanylyl cyclase (NO-GC), of which two isoforms-NO-GC1 and NO-GC2-are known, represents a promising drug target to increase cGMP in the brain. Drug-like small molecules have been discovered that work synergistically with NO to stimulate NO-GC activity. However, the effects of NO-GC stimulators in the brain are not well understood. In the present study, we used Förster/fluorescence resonance energy transfer (FRET)-based real-time imaging of cGMP in acute brain slices and primary neurons of cGMP sensor mice to comparatively assess the activity of two structurally different NO-GC stimulators, IWP-051 and BAY 41-2272, in the cerebellum, striatum and hippocampus. BAY 41-2272 potentiated an elevation of cGMP induced by the NO donor DEA/NO in all tested brain regions. Interestingly, IWP-051 potentiated DEA/NO-induced cGMP increases in the cerebellum and striatum, but not in the hippocampal CA1 area or primary hippocampal neurons. The brain-region-selective activity of IWP-051 suggested that it might act in a NO-GC isoform-selective manner. Results of mRNA in situ hybridization indicated that the cerebellum and striatum express NO-GC1 and NO-GC2, while the hippocampal CA1 area expresses mainly NO-GC2. IWP-051-potentiated DEA/NO-induced cGMP signals in the striatum of NO-GC2 knockout mice but was ineffective in the striatum of NO-GC1 knockout mice. These results indicate that IWP-051 preferentially stimulates NO-GC1 signaling in brain slices. Interestingly, no evidence for an isoform-specific effect of IWP-051 was observed when the cGMP-forming activity of whole brain homogenates was measured. This apparent discrepancy suggests that the method and conditions of cGMP measurement can influence results with NO-GC stimulators. Nevertheless, it is clear that NO-GC stimulators enhance cGMP signaling in the brain and should be further developed for the treatment of neurological diseases.
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http://dx.doi.org/10.3390/ijms19082313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6122017PMC
August 2018

Real-Time Imaging Reveals Augmentation of Glutamate-Induced Ca Transients by the NO-cGMP Pathway in Cerebellar Granule Neurons.

Int J Mol Sci 2018 Jul 26;19(8). Epub 2018 Jul 26.

Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.

Dysfunctions of NO-cGMP signaling have been implicated in various neurological disorders. We have studied the potential crosstalk of cGMP and Ca signaling in cerebellar granule neurons (CGNs) by simultaneous real-time imaging of these second messengers in living cells. The NO donor DEA/NO evoked cGMP signals in the granule cell layer of acute cerebellar slices from transgenic mice expressing a cGMP sensor protein. cGMP and Ca dynamics were visualized in individual CGNs in primary cultures prepared from 7-day-old cGMP sensor mice. DEA/NO increased the intracellular cGMP concentration and augmented glutamate-induced Ca transients. These effects of DEA/NO were absent in CGNs isolated from knockout mice lacking NO-sensitive guanylyl cyclase. Furthermore, application of the cGMP analogues 8-Br-cGMP and 8-pCPT-cGMP, which activate cGMP effector proteins such as cyclic nucleotide-gated cation channels and cGMP-dependent protein kinases (cGKs), also potentiated glutamate-induced Ca transients. Western blot analysis failed to detect cGK type I or II in our primary CGNs. The addition of phosphodiesterase (PDE) inhibitors during cGMP imaging showed that CGNs degrade cGMP mainly via Zaprinast-sensitive PDEs, most likely PDE5 and/or PDE10, but not via PDE1, 2, or 3. In sum, these data delineate a cGK-independent NO-cGMP signaling cascade that increases glutamate-induced Ca signaling in CGNs. This cGMP⁻Ca crosstalk likely affects neurotransmitter-stimulated functions of CGNs.
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http://dx.doi.org/10.3390/ijms19082185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121606PMC
July 2018

The Absence of Sensory Axon Bifurcation Affects Nociception and Termination Fields of Afferents in the Spinal Cord.

Front Mol Neurosci 2018 8;11:19. Epub 2018 Feb 8.

Developmental Neurobiology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.

A cGMP signaling cascade composed of C-type natriuretic peptide, the guanylyl cyclase receptor Npr2 and cGMP-dependent protein kinase I (cGKI) controls the bifurcation of sensory axons upon entering the spinal cord during embryonic development. However, the impact of axon bifurcation on sensory processing in adulthood remains poorly understood. To investigate the functional consequences of impaired axon bifurcation during adult stages we generated conditional mouse mutants of Npr2 and cGKI ( and ) that lack sensory axon bifurcation in the absence of additional phenotypes observed in the global knockout mice. Cholera toxin labeling in digits of the hind paw demonstrated an altered shape of sensory neuron termination fields in the spinal cord of conditional Npr2 mouse mutants. Behavioral testing of both sexes indicated that noxious heat sensation and nociception induced by chemical irritants are impaired in the mutants, whereas responses to cold sensation, mechanical stimulation, and motor coordination are not affected. Recordings from C-fiber nociceptors in the hind limb skin showed that Npr2 function was not required to maintain normal heat sensitivity of peripheral nociceptors. Thus, the altered behavioral responses to noxious heat found in mice is not due to an impaired C-fiber function. Overall, these data point to a critical role of axonal bifurcation for the processing of pain induced by heat or chemical stimuli.
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http://dx.doi.org/10.3389/fnmol.2018.00019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5809486PMC
February 2018

Dorsal root ganglion axon bifurcation tolerates increased cyclic GMP levels: the role of phosphodiesterase 2A and scavenger receptor Npr3.

Eur J Neurosci 2016 12 3;44(12):2991-3000. Epub 2016 Nov 3.

Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft, 13092, Berlin, Germany.

A cyclic GMP (cGMP) signaling pathway, comprising C-type natriuretic peptide (CNP), its guanylate cyclase receptor Npr2, and cGMP-dependent protein kinase I, is critical for the bifurcation of dorsal root ganglion (DRG) and cranial sensory ganglion axons when entering the mouse spinal cord and the hindbrain respectively. However, the identity and functional relevance of phosphodiesterases (PDEs) that degrade cGMP in DRG neurons are not completely understood. Here, we asked whether regulation of the intracellular cGMP concentration by PDEs modulates the branching of sensory axons. Real-time imaging of cGMP with a genetically encoded fluorescent cGMP sensor, RT-PCR screens, in situ hybridization, and immunohistology combined with the analysis of mutant mice identified PDE2A as the major enzyme for the degradation of CNP-induced cGMP in embryonic DRG neurons. Tracking of PDE2A-deficient DRG sensory axons in conjunction with cGMP measurements indicated that axon bifurcation tolerates increased cGMP concentrations. As we found that the natriuretic peptide scavenger receptor Npr3 is expressed by cells associated with dorsal roots but not in DRG neurons itself at early developmental stages, we analyzed axonal branching in the absence of Npr3. In Npr3-deficient mice, the majority of sensory axons showed normal bifurcation, but a small population of axons (13%) was unable to form T-like branches and generated turns in rostral or caudal directions only. Taken together, this study shows that sensory axon bifurcation is insensitive to increases of CNP-induced cGMP levels and Npr3 does not have an important scavenging function in this axonal system.
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http://dx.doi.org/10.1111/ejn.13434DOI Listing
December 2016

Sildenafil Potentiates a cGMP-Dependent Pathway to Promote Melanoma Growth.

Cell Rep 2016 Mar 10;14(11):2599-610. Epub 2016 Mar 10.

Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany. Electronic address:

Sildenafil, an inhibitor of the cGMP-degrading phosphodiesterase 5 that is used to treat erectile dysfunction, has been linked to an increased risk of melanoma. Here, we have examined the potential connection between cGMP-dependent signaling cascades and melanoma growth. Using a combination of biochemical assays and real-time monitoring of melanoma cells, we report a cGMP-dependent growth-promoting pathway in murine and human melanoma cells. We document that C-type natriuretic peptide (CNP), a ligand of the membrane-bound guanylate cyclase B, enhances the activity of cGMP-dependent protein kinase I (cGKI) in melanoma cells by increasing the intracellular levels of cGMP. Activation of this cGMP pathway promotes melanoma cell growth and migration in a p44/42 MAPK-dependent manner. Sildenafil treatment further increases intracellular cGMP concentrations, potentiating activation of this pathway. Collectively, our data identify this cGMP-cGKI pathway as the link between sildenafil usage and increased melanoma risk.
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http://dx.doi.org/10.1016/j.celrep.2016.02.028DOI Listing
March 2016

Heat-shock protein HSPB1 attenuates microRNA miR-1 expression thereby restoring oncogenic pathways in prostate cancer cells.

Anticancer Res 2014 Jul;34(7):3475-80

Department of Urology, University Medicine Greifswald, Greifswald, Germany.

Background: Heat-shock proteins (HSPs) as well as microRNAs have been identified to orchestrate crucial mechanisms in prostate cancer (PCa) progression and treatment resistance. Due to cytoprotective properties of HSPB1 we analyzed molecular mechanisms of drug resistance in PCa cell culture systems, and notably found HSPB1 functionality linked to microRNA miR-1 activities.

Materials And Methods: HSPB1 and miR-1 levels were genetically modified in PCa cell lines and alterations in molecular and cellular responses were assessed by quantitative reverse transcription/polymerase chain reaction, western blotting, and proliferation assays.

Results: Our data provided for the first time evidence that HSPB1 regulates miR-1 expression, and subsequently restores oncogenic signaling pathways of androgen receptor (AR) and transforming growth factor β1 (TGFB1).

Conclusion: Our data point towards HSPB1 and miR-1 involvement in development of castration-resistant PCa and therefore represent promising targets for anticancer therapy of advanced PCa.
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July 2014

Androgen receptor (AR) inhibitor ErbB3-binding protein-1 (Ebp1) is not targeted by the newly identified AR controlling signaling axis heat-shock protein HSP27 and microRNA miR-1 in prostate cancer cells.

World J Urol 2015 Mar 6;33(3):323-7. Epub 2014 May 6.

Department of Urology, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany,

Purpose: Androgen receptor (AR) networks are predominantly involved in prostate cancer (PCa) progression; consequently, factors of AR regulation represent promising targets for PCa therapy. The ErbB3-binding protein 1 (Ebp1) is linked to AR suppression and chemoresistance by so far unknown mechanisms. In this study, an assumed regulation of Ebp1 by the newly identified AR controlling signaling axis heat-shock protein 27 (HSP27)-microRNA-1 (miR-1) was examined.

Methods: Transfection experiments were carried out overexpressing and knockdown HSP27 and miR-1, respectively, in LNCaP and PC-3 cells. Afterward, HSP27- and miR-1-triggered Ebp1 protein expression was monitored by Western blotting.

Results: AR-positive LNCaP cells and AR-negative PC-3 cells possessed diverse basal expression levels of Ebp1. However, subsequent studies revealed no differences in cellular Ebp1 concentrations after modulation of HSP27 and miR-1. Furthermore, docetaxel incubation experiments exhibited no effects on Ebp1 protein synthesis.

Conclusion: In PCa, Ebp1 has been described as a regulator of AR functionality and as an effector of PCa therapy resistance. Our data suggest that Ebp1 functionality is independent from heat-shock-protein-regulated progression networks in PCa.
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http://dx.doi.org/10.1007/s00345-014-1307-4DOI Listing
March 2015

Shortened isoforms of the androgen receptor are regulated by the cytoprotective heat-shock protein HSPB1 and the tumor-suppressive microRNA miR-1 in prostate cancer cells.

Anticancer Res 2013 Nov;33(11):4921-6

Department of Urology, University Medicine Greifswald, Ferdinand-Sauerbruch-Str., D-17475 Greifswald, Germany,

Background: Shortened, constitutively active androgen receptor (AR) isoforms have been characterized and linked to tumor progression and chemoresistance in prostate cancer (PCa). We examined the regulation of shortened AR isoforms by a newly-identified AR regulatory signaling pathway involving heat-shock protein HSPB1 and microRNA miR-1.

Materials And Methods: HSPB1 and miR-1 were modulated by overexpression and knock-down approaches utilizing the model PCa system, 22Rv1. Subsequently, AR isoform expression levels were quantified by western blot analysis.

Results: HSPB1 was identified as an inducer and miR-1 as an inhibitor of AR variants, with no detectable discrimination between long and short AR isoform regulation.

Conclusion: In 22Rv1 cells, all AR isoforms were co-regulated by the cytoprotective factor HSPB1 and the tumor suppressor miR-1. Notably, our data provide evidence that HSPB1 inhibition is able to target expression of long as well as of short AR isoforms.
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November 2013
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