Brad Dieter

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Papers by Brad Dieter

Sodium–Glucose Cotransporter 2 Inhibition and Diabetic Kidney Disease

Diabetes, Jan 14, 2019

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Effect of Small and Large Energy Surpluses on Strength, Muscle, and Skinfold Thickness

Research Square (Research Square), Aug 2, 2023

Background A goal of many who perform resistance training (RT) is to increase muscle mass and str... more Background A goal of many who perform resistance training (RT) is to increase muscle mass and strength. An energy surplus is commonly advised to support such gains; however, if too large, it could cause unwanted fat gain without augmenting adaptation. Thus, we randomized 21 trained lifters into maintenance energy (MAIN), 5% (MOD), and 15% (HIGH) energy surplus groups while performing RT 3d/wk for eight weeks to determine if skinfold thicknesses (ST), squat and bench one-repetition maximum (1-RM), or biceps brachii or quadriceps muscle thicknesses (MT) were in uenced by group assignment. COVID-19 complications reduced our ability to recruit and retain participants, leaving 17 completers. Thus, in addition to Bayesian ANCOVA group comparisons, we regressed outcomes against body mass (BM) changes to analyze the relationship between BM gain, ST increases, and increase in 1-RM and MT. For all outcomes we reported Bayes Factors (BF 10) indicating the odds ratio of the likelihood of one hypothesis relative to another (e.g., a BF 10 = 2 indicates the hypothesis is twice as likely as another) and coe cients of determination (R 2) for regressions. Results ANCOVAs provided no evidence in support of the group model for MT or squat 1-RM. However, there was moderate (BF 10 = 9.9) and strong evidence (BF 10 = 14.5) that MOD increased bench 1-RM more than HIGH and MAIN, respectively. Further, there was moderate evidence (BF 10 = 4.2) MOD increased ST more than MAIN and weak evidence (BF 10 = 2.4) HIGH increased ST more than MAIN. The regression provided strong evidence that BM changes predicted changes in ST (BF 10 = 14.3, R 2 = 0.49) and weak evidence that BM changes predicted changes in biceps MT (BF 10 = 1.4, R 2 = 0.24), but no evidence any other variable was predicted by BM changes. Conclusions While some group-based differences were found, our larger N regression provides the most generalizable evidence. Therefore, we conclude faster rates of BM gain (and by proxy larger surpluses) primarily increase rates of ST gain rather than augmenting 1-RM or MT. However, the biceps, the muscle group which received the greatest stimulus in this study, may have been positively impacted by greater BM gain, albeit slightly. Our ndings are limited to the con nes of this study, where a group of lifters with mixed training experience performed moderate volumes 3d/wk for eight weeks. Thus, future work is needed to evaluate the relationship between BM gains, increases in ST and RT adaptations in other contexts.

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Transdermal delivery of carnosine into equine skeletal muscle

Comparative Exercise Physiology, May 24, 2021

The dipeptide carnosine consists of β-alanine and L-histidine. It plays a major role in skeletal ... more The dipeptide carnosine consists of β-alanine and L-histidine. It plays a major role in skeletal muscle metabolism, especially as an intracellular buffer and antioxidant. Increasing intramuscular carnosine has been shown to improve recovery from exercise and increase anaerobic threshold and time-to-exhaustion. Dietary supplementation with carnosine does not effectively increase intramuscular carnosine due to the presence of carnosinase in the blood. However, an effective transdermal delivery process could expediently increase intramuscular concentrations of carnosine. This study’s objective was to examine the efficacy of a transdermal system for delivering carnosine into the skeletal muscle of horses, using a randomised, placebo controlled, crossover study. Carnosine plus a proprietary transdermal delivery agent or the agent alone (placebo) were applied to the middle gluteal muscles of 10 Thoroughbred racehorses, and muscle biopsies were taken before and 30, 60, and 120 min after application. Muscle carnosine concentration was measured using an enzyme-linked immunosorbent assay. A two-way repeated measures analysis of variance was used to test for the main effects of time and treatment (placebo or carnosine) as well as an interaction between time and treatment. Independent F-tests examined the change in intramuscular carnosine levels from baseline to each time point (30, 60, and 120 min). There was a significant main effect of treatment (P=0.004), no significant main effect for time (P=0.18), and a non-significant interaction of treatment with time (P=0.08). Mean intramuscular carnosine concentrations increased from baseline to 120 min. Compared to concentrations following placebo application, carnosine was greater by ~35% at 30 min (P=0.002) and ~46% after 60 min (P=0.044), but not at 120 min (P=0.20). The results indicated that intramuscular carnosine can be increased using a transdermal delivery system within 60 min of application which could have important implications for the health of horses, and their capacity to perform and recover from physical activity.

Exponential Modeling of VO2 Kinetics in Endurance-Trained Diabetic Mice

International Journal of Exercise Science: Conference Proceedings, 2015

Rodent models of type 2 diabetes mellitus (T2DM) are often used to study aerobic exercise trainin... more Rodent models of type 2 diabetes mellitus (T2DM) are often used to study aerobic exercise training (AET) in diabetes. However, it is not known how T2DM affects oxygen consumption (VO2) kinetics in rodents, or whether rodent fitness is improvedby the same low- to moderate-intensity exercise that is prescribed for humans with T2DM. PURPOSE: The purpose of this study was to determine the effects of T2DM and exercise on VO2 kinetic parameters in mice. METHODS: Non-diabetic (C57) and genetically type 2 diabetic (db/db; DB) mice were treadmill trained for eight weeks. Mice completed maximal exercise tests in a metabolic modular treadmill at baseline, week 4, and week 8. Weekly exercise progressed from 40-70% of the peak workload achieved in these tests. VO2 data were smoothed using LOWESS regression and fitted to a one-component (1C) and a 2C exponential kinetic model. RESULTS: After eight weeks of training, absolute VO2 was significantly increased from baseline in both DB (239 ± 14 ml/min vs 189 ± 6, PDB mice was 83% lower than C57 mice. A 1C exponential model showed that the VO2 intercept for weeks 0, 4, and 8 was significantly lower in DB mice than C57 mice (P2max when fitted to the whole exercise protocol and the on-transient of exercise, respectively. CONCLUSION: These data provide reference values for VO2max in DB mice, and show that a 1C exponential model is more useful than a 2C model for determining τ in diabetic mice. Low- to moderate-intensity exercise training increased absolute VO2max in both DB and C57 mice without changing τ, suggesting that cardiovascular fitness can improve independent of VO2 kinetics in these mice

Women with COPD Experience Increased Symptom Burden, Frequent and Severe Exacerbation, and Impaired Functional Capacity as compared to Men in SPIROMICS

PowerPoint Slides for: Medication Intervention for Chronic Kidney Disease Patients Transitioning from Hospital to Home: Study Design and Baseline Characteristics

Background: The hospital readmission rate in the population with chronic kidney disease (CKD) is ... more Background: The hospital readmission rate in the population with chronic kidney disease (CKD) is high and strategies to reduce this risk are urgently needed. Methods: The CKD-Medication Intervention Trial (CKD-MIT; www.clinicaltrials.gov; NCTO1459770) is a single-blind (investigators), randomized, clinical trial conducted at Providence Health Care in Spokane, Washington. Study participants are hospitalized patients with CKD stages 3-5 (not treated with kidney replacement therapy) and acute illness. The study intervention is a pharmacist-led, home-based, medication management intervention delivered within 7 days after hospital discharge. The primary outcome is a composite of hospital readmissions and visits to emergency departments and urgent care centers for 90 days following hospital discharge. Secondary outcomes are achievements of guideline-based targets for CKD risk factors and complications. Results: Enrollment began in February 2012 and ended in May 2015. At baseline, the age ...

Supplementary Material for: Medication Intervention for Chronic Kidney Disease Patients Transitioning from Hospital to Home: Study Design and Baseline Characteristics

Background: The hospital readmission rate in th... more Background: The hospital readmission rate in the population with chronic kidney disease (CKD) is high and strategies to reduce this risk are urgently needed. Methods: The CKD-Medication Intervention Trial (CKD-MIT; www.clinicaltrials.gov; NCTO1459770) is a single-blind (investigators), randomized, clinical trial conducted at Providence Health Care in Spokane, Washington. Study participants are hospitalized patients with CKD stages 3-5 (not treated with kidney replacement therapy) and acute illness. The study intervention is a pharmacist-led, home-based, medication management intervention delivered within 7 days after hospital discharge. The primary outcome is a composite of hospital readmissions and visits to emergency departments and urgent care centers for 90 days following hospital discharge. Secondary outcomes are achievements of guideline-based targets for CKD risk factors and complications. Results: Enrollment began in February 2012 and ended in May 2015. At baseline, the age of participants was 69 ± 11 years (mean ± SD), 50% (77 of 155) were women, 83% (117 of 141) had hypertension and 56% (79 of 141) had diabetes. At baseline, the estimated glomerular filtration rate was 41 ± 14 ml/min/1.73 m2 and urine albumin-to-creatinine ratio was 43 mg/g (interquartile range 8-528 mg/g). The most frequent diagnosis category for the index hospital admission was cardiovascular diseases at 34% (53 of 155), but the most common single diagnosis for admission was community-acquired acute kidney injury at 10% (16 of 155). Conclusion: Participants in CKD-MIT are typical of acutely ill hospitalized patients with CKD. A medication management intervention after hospital discharge is under study to reduce post-hospitalization acute care utilization and to improve CKD management.

Effect of Small and Large Energy Surpluses on Strength, Muscle, and Skinfold Thickness in Resistance-Trained Individuals: A Parallel Groups Design

Sports Medicine - Open

Background Many perform resistance training (RT) to increase muscle mass and strength. Energy sur... more Background Many perform resistance training (RT) to increase muscle mass and strength. Energy surpluses are advised to support such gains; however, if too large, could cause unnecessary fat gain. We randomized 21 trained lifters performing RT 3 d/wk for eight weeks into maintenance energy (MAIN), moderate (5% [MOD]), and high (15% [HIGH]) energy surplus groups to determine if skinfold thicknesses (ST), squat and bench one-repetition maximum (1-RM), or biceps brachii, triceps brachii, or quadriceps muscle thicknesses (MT) differed by group. COVID-19 reduced our sample, leaving 17 completers. Thus, in addition to Bayesian ANCOVA comparisons, we analyzed changes in body mass (BM) with ST, 1-RM, and MT changes via regression. We reported Bayes factors (BF10) indicating odds ratios of the relative likelihood of hypotheses (e.g., BF10 = 2 indicates the hypothesis is twice as likely as another) and coefficients of determination (R2) for regressions. Results ANCOVAs provided no evidence sup...

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Knockdown of the 110kDa Subunit of OGT Dysregulates Cardiac Remodeling in Response to Pressure Overload

The FASEB Journal, 2015

Muscle Activation Patterns Differ Between Cyclists with Patellofemoral Pain and Those Without

B.P. Dieter University of Idaho, Moscow, ID Patellofemoral pain (PFP) syndrome is pervasive and d... more B.P. Dieter University of Idaho, Moscow, ID Patellofemoral pain (PFP) syndrome is pervasive and debilitating in the sport of cycling. It occurs in 36% of professional cyclists and has been shown to account for more than 57% of all time-loss injuries. Despite the body of literature relating to PFP and the high rate of occurrence in cycling, little is known about the underlying mechanisms causing PFP in cyclists. In order to prevent and treat PFP syndrome in the sport of cycling, a clear understanding of the mechanisms responsible for causing the pathology needs to be developed. PURPOSE: The purpose of this study was to determine if there were differences in muscle activation patterns (onset and offset time) of the vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST), and biceps femoris (BF) between cyclists with and without PFP during submaximal cycling. METHODS: 10 healthy cyclists (6 female, 4 male; Weight=71.9±16.5 kg; Age=40.2± 12.2 yrs; Cycling Experience=123.9±51.6 miles/week) were matched with 7 cyclists with PFP syndrome (1 female, 6 male; Weight=79.8±9.4 kg; Age 46.4±13.8; Cycling Experience=142±3 miles/week) Each participant completed a 10 min warm-up followed by a 10 min cycling trial during which surface EMG was recorded for the VM, VL, ST, and BF muscles. Sagittal plane knee kinematic data were also recorded using an electrogoniometer. An analysis of variance was conducted to compare differences between groups with alpha level set at 0.05 RESULTS: Baseline characteristics were similar between groups (p\u3e0.05). No significant difference between groups was found for the relative onset times of the VM and VL (VMVLON) (p=0.805). There were significant differences between groups for the relative offset time of the VM and VL (VMVLOFF) (p=0.032), with the PFP group displaying earlier relative offset time of the VM. There was also a significant difference in the relative onset time of BF and ST (STBFON) (pOFF) (p=0.024) with the PFP group displaying later BF offset. CONCLUSION: These data suggest trained cyclists with PFP syndrome display different muscle activation patterns than asymptomatic cyclists, potentially resulting in altered patellofemoral kinematics

O-GlcNAc Plays a Role in Nrf2 Regulation in the Myocardium

The FASEB Journal, 2015

The redox sensitive transcription factor NF-E2–related factor 2 (Nrf2) protects against oxidative... more

Supplementary Material for: Association of Serum Amyloid A with Kidney Outcomes and All-Cause Mortality in American Indians with Type 2 Diabetes

Background: Serum amyloid A (SAA) induces inflammation and ... more Background: Serum amyloid A (SAA) induces inflammation and apoptosis in kidney cells and is found to be causing the pathologic changes that are associated with diabetic kidney disease (DKD). Higher serum SAA concentrations were previously associated with increased risk of end-stage renal disease (ESRD) and death in persons with type 2 diabetes and advanced DKD. We explored the prognostic value of SAA in American Indians with type 2 diabetes without DKD or with early DKD. Methods: SAA concentration was measured in serum samples obtained at the start of follow-up. Multivariate proportional hazards models were employed to examine the magnitude of the risk of ESRD or death across tertiles of SAA concentration after adjustment for traditional risk factors. The C statistic was used to assess the additional predictive value of SAA relative to traditional risk factors. Results: Of 256 participants (mean ± SD glomerular filtration rate [iothalamate] = 148 ± 45 mL/min, and median [interquartile range] urine albumin/creatinine = 39 [14-221] mg/g), 76 developed ESRD and 125 died during a median follow-up period of 15.2 and 15.7 years, respectively. After multivariable proportional hazards regression, participants in the 2 highest SAA tertiles together exhibited a 53% lower risk of ESRD (hazard ratio [HR] 0.47, 95% CI 0.29-0.78), and a 30% lower risk of death (HR 0.70, 95% CI 0.48-1.02), compared with participants in the lowest SAA tertile, although the lower risk of death was not statistically significant. Addition of SAA to the ESRD model increased the C statistic from 0.814 to 0.815 (p = 0.005). Conclusions: Higher circulating SAA concentration is associated with a reduced risk of ESRD in American Indians with type 2 diabetes.

Posibles Efectos Ergogénicos de la Vitamina D Sobre el Rendimiento y la Recuperación Deportiva

Association of Acute Kidney Injury with Cardiovascular Events and Death in Systolic Blood Pressure Intervention Trial

American Journal of Nephrology, 2019

Rationale and Objective: In the Systolic Blood Pressure Intervention Trial, the possible relation... more Rationale and Objective: In the Systolic Blood Pressure Intervention Trial, the possible relationships between acute kidney injury (AKI) and risk of major cardiovascular events and death are not known. Study Design: Post hoc analysis of a multicenter, randomized, controlled, open-label clinical trial. Setting and Participants: Hypertensive adults without diabetes who were ≥50 years of age with prior cardiovascular disease, chronic kidney disease (CKD), 10-year Framingham risk score > 15%, or age > 75 years were assigned to a systolic blood pressure target of < 120 mm Hg (intensive) or < 140 mm Hg (standard). Predictor: AKI episodes. Outcomes: The primary outcome was a composite of myocardial infarction, acute coronary syndrome, stroke, decompensated heart failure, or cardiovascular death. The secondary outcome was death from any cause. Analytical Approach: AKI was defined using the Kidney Disease: Improving Global Outcomes modified criteria based solely upon serum creati...

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Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training

Frontiers in Nutrition, 2019

Resistance training is commonly prescribed to enhance strength/power qualities and is achieved vi... more Resistance training is commonly prescribed to enhance strength/power qualities and is achieved via improved neuromuscular recruitment, fiber type transition, and/ or skeletal muscle hypertrophy. The rate and amount of muscle hypertrophy associated with resistance training is influenced by a wide array of variables including the training program, plus training experience, gender, genetic predisposition, and nutritional status of the individual. Various dietary interventions have been proposed to influence muscle hypertrophy, including manipulation of protein intake, specific supplement prescription, and creation of an energy surplus. While recent research has provided significant insight into optimization of dietary protein intake and application of evidence based supplements, the specific energy surplus required to facilitate muscle hypertrophy is unknown. However, there is clear evidence of an anabolic stimulus possible from an energy surplus, even independent of resistance training. Common textbook recommendations are often based solely on the assumed energy stored within the tissue being assimilated. Unfortunately, such guidance likely fails to account for other energetically expensive processes associated with muscle hypertrophy, the acute metabolic adjustments that occur in response to an energy surplus, or individual nuances like training experience and energy status of the individual. Given the ambiguous nature of these calculations, it is not surprising to see broad ranging guidance on energy needs. These estimates have never been validated in a resistance training population to confirm the "sweet spot" for an energy surplus that facilitates optimal rates of muscle gain relative to fat mass. This review not only addresses the influence of an energy surplus on resistance training outcomes, but also explores other pertinent issues, including "how much should energy intake be increased," "where should this extra energy come from," and "when should this extra energy be consumed." Several gaps in the literature are identified, with the hope this will stimulate further research interest in this area. Having a broader appreciation of these issues will assist practitioners in the establishment of Slater et al. Energy Surplus and Resistance Training dietary strategies that facilitate resistance training adaptations while also addressing other important nutrition related issues such as optimization of fuelling and recovery goals. Practical issues like the management of satiety when attempting to increase energy intake are also addressed.

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Moving Sport and Exercise Science Forward: A Call for the Adoption of More Transparent Research Practices

The primary means for disseminating sport and exercise science research is currently through jour... more The primary means for disseminating sport and exercise science research is currently through journal articles. However, not all studies, especially those with null ﬁndings, make it to formal publication. This publication bias towards positive ﬁndings may contribute to questionable research practices. Preregistration is a solution to prevent the publication of distorted evidence resulting from this system. This process asks authors to register their hypotheses and methods before data collection on a publicly available repository or by submitting a Registered Report. In the Registered Reports format, authors submit a Stage 1 manuscript to a participating journal that includes an introduction, methods, and any pilot data indicating the exploratory or conﬁrmatory nature of the study. After a Stage 1 peer review, the manuscript can then be oﬀered in-principle acceptance, rejected, or sent back for revisions to improve the quality of the study. If accepted, the project is guaranteed publi...

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GLP-1 receptor agonists in diabetic kidney disease: from the patient-side to the bench-side

American Journal of Physiology-Renal Physiology, 2018

Diabetic kidney disease (DKD), one of the most common and severe microvascular complications of d... more Diabetic kidney disease (DKD), one of the most common and severe microvascular complications of diabetes, is the leading cause of chronic kidney disease and end-stage kidney disease worldwide. Since the development of renin-angiotensin system inhibition nearly three decades ago, no new therapeutic agents have received regulatory approval for treatment of DKD. Glucagon-like peptide-1 (GLP-1) receptor agonists, a class of newer antihyperglycemic agents, have shown promise for prevention of DKD onset and progression. This perspective summarizes clinical and experimental observations to give insight into biological mechanisms beyond glycemic control, such as natriuresis and anti-inflammatory actions, for preservation of kidney function in patients with diabetes.

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Effects of macro- and micronutrients on exercise-induced hepcidin response in highly trained endurance athletes

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 2017

Iron deficiency has ergolytic effects on athletic performance. Exercise-induced inflammation impe... more Iron deficiency has ergolytic effects on athletic performance. Exercise-induced inflammation impedes iron absorption in the digestive tract by upregulating the expression of the iron regulatory protein, hepcidin. Limited research indicates the potential of specific macro- and micronutrients on blunting exercise-induced hepcidin. Therefore, we investigated the effects of postexercise supplementation with protein and carbohydrate (CHO) and vitamins D and K on the postexercise hepcidin response. Ten highly trained male cyclists (age: 26.9 ± 6.4 years; maximal oxygen uptake: 67.4 ± 4.4 mL·kg·min completed 4 cycling sessions in a randomized, placebo-controlled, single-blinded, triple-crossover study. Experimental days consisted of an 8-min warm-up at 50% power output at maximal oxygen uptake, followed by 8 × 3-min intervals at 85% power output at maximal oxygen uptake with 1.5 min at 60% power output at maximal oxygen uptake between each interval. Blood samples were collected pre- and po...

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Medication Therapy Management after Hospitalization in CKD: A Randomized Clinical Trial

Clinical journal of the American Society of Nephrology : CJASN, Jan 7, 2018

CKD is characterized by remarkably high hospitalization and readmission rates. Our study aim was ... more CKD is characterized by remarkably high hospitalization and readmission rates. Our study aim was to test a medication therapy management intervention to reduce subsequent acute care utilization. The CKD Medication Intervention Trial was a single-blind (investigators), randomized clinical trial conducted at Providence Health Care in Spokane, Washington. Patients with CKD stages 3-5 not treated by dialysis who were hospitalized for acute illness were recruited. The intervention was designed to improve posthospitalization care by medication therapy management. A pharmacist delivered the intervention as a single home visit within 7 days of discharge. The intervention included these fundamental elements: comprehensive medication review, medication action plan, and a personal medication list. The primary outcome was a composite of acute care utilization (hospital readmissions and emergency department and urgent care visits) for 90 days after hospitalization. Baseline characteristics of pa...

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Muscle Weakness and Diabetes Jointly Exacerbate the Rate of Functional Disability among Older Mexican Americans

Medicine & Science in Sports & Exercise, 2017