Ceren Yarar-Fisher

Dr. Ceren Yarar-Fisher


Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
21 November 2022 in Physiological Reports
Verified
Journal Article
Open access
JLJia Li
Jia Li
BGBarbara Gower
Barbara Gower
AMAmie McLain
Amie McLain
CYCeren Yarar-Fisher
Ceren Yarar-Fisher
We explored the impact of a low‐carbohydrate/high‐protein diet (LC/HP, ~30% energy from protein, 40% energy from carbohydrate) on indices of metabolic function and body composition in individuals with chronic spinal cord injury (SCI). Adults with SCI (≥3 years post‐injury, C4‐L2, AIS A‐D) and insulin resistance or pre‐diabetes were randomly assigned to an 8‐week iso‐caloric LC/HP diet group (n = 11) or control group (n = 14). All LC/HP meals were delivered weekly to participants' homes, and participants in the control group consumed their habitual diet. Each participant underwent an oral glucose tolerance test (OGTT) to assess glucose tolerance, insulin, area under the curve (AUC) for glucose and insulin, Matsuda Index, glucose‐stimulated insulin secretion (GSIS), disposition index, and hepatic insulin extraction (HIE). Fasting blood lipid and inflammation were assessed, and body composition was estimated using dual‐energy x‐ray absorptiometry. A linear mixed model was used to evaluate the main effect of diet, time, and their interaction. Compared to the control group, participants in the LC/HP group had reduced total body fat mass (LC/HP: −5.9%, Control: 0.7%), visceral fat mass (LC/HP: −16.2%, Control: 5.2%), total‐ (LC/HP: −20.1, Control: 3.7 mg/dl), and LDL‐cholesterol (LC/HP: −13.9, Control: 3.1 mg/dl) (pdiet*time < 0.05 for all). Regardless of group, AUCinsulin and peak insulin during the OGTT decreased, and HIE increased over time (ptime < 0.05). A trend for diet*time interaction was observed for glucoseOGTT120min (LC/HP: −20.7, Control: 3.0 mg/dl, pdiet*time = 0.09) and peak C‐peptide (LC/HP: −2.1, Control: 0.0 ng/ml, pdiet*time = 0.07). HDL‐cholesterol, lean body mass, Matsuda Index, fasting glucose, insulin, insulinOGTT120min, AUCglucose, pancreatic beta cell function (GSIS, disposition index), and inflammation (C‐reactive protein, IL‐6, IL‐8, IL‐10, TNF‐α) did not change over time. In conclusion, our results suggest that individuals with SCI and insulin resistance may adopt an LC/HP diet to improve body composition and lipid profiles. Its impact on glucose metabolism and inflammation remains inconclusive and warrants future investigations.

AAAmal Alharbi
Amal Alharbi
JLJia Li
Jia Li
EWErika Womack
Erika Womack
MFMatthew Farrow
Matthew Farrow
CYCeren Yarar-Fisher
Ceren Yarar-Fisher
Maintaining healthy myofiber type and metabolic function early after spinal cord injury (SCI) may prevent chronic metabolic disorders. This study compares the effects of a 2–5 week combined (aerobic + resistance) neuromuscular electrical stimulation (Comb-NMES) regimen versus a sham control treatment on muscle protein signaling for glucose uptake, myofiber type distribution, and metabolic function. Twenty participants (31 ± 9 years of age) with an SCI (C4-L1, AIS level A–C) within 14 days of the SCI were randomly assigned to control (N = 8) or Comb-NMES (N = 12). Sessions were given three times per week. Fasting blood samples and vastus lateralis muscle biopsies were collected 24–48 h before or after the last session. Western blots were performed to quantify proteins, immunohistochemical analyses determined muscle myofiber distribution, and enzymatic assays were performed to measure serum glucose, insulin, and lipids. Our main findings include a decrease in fasting glucose (p < 0.05) and LDL-C (p < 0.05) levels, an upregulation of CamKII and Hexokinase (p < 0.05), and an increase in type I (+9%) and a decrease in type IIx (−36%) myofiber distribution in response to Comb-NMES. Our findings suggest that maintaining healthy myofiber type and metabolic function may be achieved via early utilization of Comb-NMES.

4 August 2022 in Trials
Verified
Journal Article
Open access
PDF file
JAJacob J. Adams
Jacob J. Adams
BLByron Lai
Byron Lai
JRJIM H RIMMER
JIM H RIMMER
DPDanielle Powell
Danielle Powell
CYCeren Yarar-Fisher
Ceren Yarar-Fisher
GFGordon Fisher
Gordon Fisher
Background: The number of exercise trials examining cardiometabolic outcomes in spinal cord injury (SCI) is low, and prescribed exercise is often inconvenient for individuals with SCI to perform within their community. Individuals with SCI experience a myriad of barriers to exercise participation, which can include a lack of time, accessible or usable equipment and facilities, and transportation. Thus, it is imperative to identify effective modes of exercise that provide the greatest overall health benefits but do not require a significant time commitment. Low-volume high intensity interval training (HIIT) has demonstrated the same improvements in cardiometabolic health as moderate intensity exercise training (MIT), despite only requiring 20% of the total time commitment in adults without disabilities and more recently in individuals with SCI. Objectives: The primary purpose of this study is to integrate a 16 week home-based telehealth HIIT arm crank exercise training program in individuals with SCI and assess changes in cardiometabolic health. Methods: Men and women between the ages of 19 and 60 with a confirmed diagnosis of SCI between C7 and T12 will be recruited for this study. Participants will be randomized to 16 weeks of telehealth HIIT exercise two days per week or a no-exercise control group. Aerobic capacity, muscular strength, blood lipids, glucose tolerance, resting energy expenditure, blood pressure, and body composition will be assessed at baseline and 16 weeks post-training. Discussion: Inactivity associated with SCI leads to chronic cardiometabolic health conditions. The majority of exercise interventions to date show that exercise is capable of increasing physical function, aerobic capacity, and muscle mass, and strength. Additionally, we have recently shown the ability of HIIT to improve blood lipid and glucose concentrations. Advances in telehealth exercise approaches have improved the capability to prescribe home-based exercise programs. Therefore, we hypothesize that the utilization of a home-based telehealth HIIT program will improve cardiometabolic health markers, yield high adherence (> 75%), and will be more enjoyable in individuals with SCI. Trial registration: Telehealth High-Intensity Interval Exercise and Cardiometabolic Health in Spinal Cord Injury NCT04940598

Verified
Journal Article
Open access
PDF file
AAAmal Alharbi
Amal Alharbi
JLJia Li
Jia Li
EWErika Womack
Erika Womack
MFMatthew Farrow
Matthew Farrow
CYCeren Yarar-Fisher
Ceren Yarar-Fisher
In individuals with a spinal cord injury (SCI), rapid skeletal muscle atrophy and metabolic dysfunction pose profound rehabilitation challenges, often resulting in substantial loss of muscle mass and function. This study evaluates the effect of combined neuromuscular electrical stimulation (Comb-NMES) on skeletal muscle cross-sectional area (CSA) and inflammatory signaling within the acute phase of SCI. We applied a novel Comb-NMES regimen, integrating both high-frequency resistance and low-frequency aerobic protocols on the vastus lateralis muscle, to participants early post-SCI. Muscle biopsies were analyzed for CSA and inflammatory markers pre- and post-intervention. The results suggest a potential preservation of muscle CSA in the Comb-NMES group compared to a control group. Inflammatory signaling proteins such as TLR4 and Atrogin-1 were downregulated, whereas markers associated with muscle repair and growth were modulated beneficially in the Comb-NMES group. The study’s findings suggest that early application of Comb-NMES post-SCI may attenuate inflammatory pathways linked to muscle atrophy and promote muscle repair. However, the small sample size and variability in injury characteristics emphasize the need for further research to corroborate these results across a more diverse and extensive SCI population.

15 December 2017 in Spinal Cord Series and Cases
Verified
Journal Article
Open access
PDF file
BWBrent Womble
Brent Womble
ETEdward Taub
Edward Taub
BHBrennan Hickson
Brennan Hickson
JPJoshua Purvis
Joshua Purvis
VMVictor W. Mark
Victor W. Mark
GUGitendra Anthony Uswatte
Gitendra Anthony Uswatte
Introduction The purpose of this case study was to determine if a subject with chronic high tetraplegia (C3 AIS A) could learn to use an initially paralyzed upper extremity on the basis of training procedures alone. Case presentation Initially, an AIS examination revealed no purposive movement below the neck other than minimal shoulder movement. Training was carried out weekly over 39 months. Training began based on electromyographic biofeedback; the electrical activity of a muscle (biceps or triceps) was displayed visually on a computer monitor and the subject was encouraged to progressively increase the magnitude of the response in small increments on a trial-by-trial basis (i.e., shaping). When small, overt movements began to appear; these were, in turn, shaped so that their excursion progressively increased. Training then progressed to enable lifting the arm with the aid of the counterweight of a Swedish Help Arm. Mean movement excursions in the best session were: internal rotation 52.5 cm; external rotation 26.9 cm; shoulder extension 22.1 cm; shoulder flexion 15.2 cm; pronation/supination 120°; extension of index finger (D2) 2.5 cm. Movements were initially saltatory, becoming smoother over time. With the Swedish Help Arm, the subject was able to lift her hand an average of 24.3 cm in the best session with 0.7 kg counterweight acting at the wrist (1.9 J of work). Discussion Results suggest in preliminary fashion the effectiveness of this approach for improving upper extremity function after motor complete high tetraplegia. Thus, future studies are warranted. Possible mechanisms are discussed.

28 January 2025 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
AAAmal Alharbi
Amal Alharbi
EWErika Womack
Erika Womack
CYCeren Yarar-Fisher
Ceren Yarar-Fisher
Introduction: This case report examines the impact of a novel combined neuromuscular electrical stimulation (Comb-NMES) regimen on muscle glucose signaling, fiber type distribution, and metabolic function in a patient with acute spinal cord injury (SCI) and lower motor neuron lesions (LMNLs). Case Report: A 32-year-old male with complete T9 SCI underwent a ten-session Comb-NMES intervention targeting the quadriceps. Muscle biopsies and blood samples were analyzed pre- and post-intervention to evaluate changes in muscle fiber types, key metabolic proteins, fasting insulin, glucose, and lipid profiles. Results: The intervention led to a 74.7% and 28.2% reduction in fasting insulin and glucose, respectively. Muscle analysis showed significant increases in CaMK II, Hexokinase II, and IRS-1, indicating improved glucose metabolism. Conclusions: Comb-NMES training markedly improved metabolic control and muscle glucose metabolism in a patient with acute SCI and LMNLs. Enhanced insulin sensitivity and glucose utilization were evidenced by upregulated metabolic proteins, which suggests that Comb-NMES is a promising intervention for improving muscle and metabolic health in SCI patients with LMNLs. Further studies are needed to confirm these benefits and explore the long-term effects.