Inflammatory diseases causing joint and bone destruction: rheumatoid arthritis and hemophilic arthropathy.

Various diseases and conditions cause joint disorders. Osteoarthritis (OA) is characterized by the degeneration of articular cartilage, synovitis, and anabolic changes in surrounding bone tissues. In contrast, rheumatoid arthritis (RA) and hemophilic arthropathy (HA) display marked destruction of bone tissues caused by synovitis. RA is a representative autoimmune disease. The primary tissue of RA pathogenesis is the synovial membrane and involves various immune cells that produce catabolic cytokines and enzymes. Hemophilia is a genetic disorder caused by a deficiency in blood clotting factors. Recurrent intra-articular bleeding leads to chronic synovitis through excessive iron deposition and results in the destruction of affected joints. Although the triggers for these two joint diseases are completely different, many cytokines and enzymes are common in the pathogenesis of both RA and HA. This review focuses on the similarities between joint and bone destruction in RA and HA. The insights may be useful in developing better treatments for hemophilia patients with arthropathy and osteoporosis by leveraging advanced therapeutics for RA.

Preparation of [1'-13 C]citric acid as a probe in a breath test to evaluate tricarboxylic acid cycle flux.

[1'-13 C]Citric acid (1) was efficiently prepared from dimethyl 1,3-acetonedicarboxylate in two steps as a probe for a breath test. The synthetic method was selected because of the yield and reproducibility. Compound 1 was orally administrated to rats, and the time course of the increase of 13 CO2 /12 CO2 ratios (Δ13 CO2 ) in their breath was successfully followed, indicating the metabolism of 1. Thus, the 13 C-breath test using 1 is a promising method to evaluate tricarboxylic acid (TCA) cycle flux.

Systematic review and meta-analysis for the 2024 update of the Japan College of Rheumatology clinical practice guidelines for the management of rheumatoid arthritis.

OBJECTIVES: To update evidence on the efficacy and safety of disease-modifying antirheumatic drugs (DMARDs) and provide information to the taskforce for the 2024 update of the Japan College of Rheumatology (JCR) clinical practice guidelines (CPG) for the management of rheumatoid arthritis (RA). METHODS: We searched various databases for randomised controlled trials on RA published until June 2022, with no language restriction. For each of the 15 clinical questions, 2 independent reviewers screened the articles, evaluated the core outcomes, and performed meta-analyses. RESULTS: Subcutaneous injection of methotrexate (MTX) showed similar efficacy to oral MTX in MTX-naïve RA patients. Ozoralizumab combined with MTX improved drug efficacy compared to the placebo in RA patients with inadequate response (IR) to csDMARD. Rituximab with and without concomitant csDMARDs showed similar efficacy to other bDMARDs in bDMARD-IR RA patients. Combined Janus kinase inhibitors and MTX achieved similar clinical responses and equal safety during a 4-year period compared to tumour necrosis factor inhibitors in MTX-IR RA patients. Biosimilars showed efficacy equivalent to that of the original bDMARDs in csDMARD-IR and bDMARD-IR RA patients. CONCLUSION: This systematic review provides latest evidence for the 2024 update of the JCR CPG for RA management.

Combining age, sex, body mass index, sport level, and preoperative quadriceps strength improves the predictive ability of quadriceps strength recovery after anterior cruciate ligament reconstruction.

PURPOSE: This study compared the predictive ability of each independent predictor with that of a combination of predictors for quadriceps strength recovery one year after anterior cruciate ligament (ACL) reconstruction. METHODS: Patients who underwent primary ACL reconstruction using hamstring autografts were enrolled. Quadriceps strength, hamstring strength, and anterior tibial translation were measured, and the limb symmetry index (LSI) of the quadriceps and the hamstrings was calculated preoperatively and one year after surgery. Patients were classified into two groups according to the LSI of the quadriceps strength at one year postoperatively (≥ 80% or < 80%). Multivariate logistic regression analysis identified the independent predictors of quadriceps strength recovery, and the cut-off value was calculated using the receiver operating characteristic curve. A model assessing predictive ability of the combination of independent predictors was created, and the area under the curve (AUC) for each independent predictor was calculated by using the receiver-operating characteristic curves and the DeLong method. RESULTS: Of the 646 patients, 414 (64.1%) had an LSI of at least 80% for quadriceps strength one year after surgery, and 232 patients (35.9%) had an LSI of < 80%. Age, sex, body mass index (BMI), preinjury sport level, and LSI of preoperative quadriceps strength were independently associated with quadriceps strength recovery one year after ACL reconstruction. The cut-off values were age: 22.5 years; sex: female; BMI: 24.3 kg/m2; preinjury sport level: no sport; and LSI of preoperative quadriceps strength: 63.3%. The AUC of the model assessing the predictive ability of the combination of age, sex, BMI, preinjury sport level, and LSI of preoperative quadriceps strength was significantly higher (0.73) than that of similar factors of preoperative quadriceps strength (AUC: 0.63, 0.53, 0.56, 0.61, and 0.68, p < 0.01, respectively). CONCLUSION: The combination of age, sex, BMI, preinjury sport level, and LSI of preoperative quadriceps strength had a superior predictive ability for quadriceps strength recovery at one year after ACL reconstruction than these predictors alone. Multiple factors, including patient characteristics and preoperative quadriceps strength, should be considered when planning rehabilitation programs to improve quadriceps strength recovery after ACL reconstruction. LEVEL OF EVIDENCE: III.

Extension contracture stiff knee in haemophilia: Surgical timing and procedure for total knee arthroplasty.

INTRODUCTION: Total knee arthroplasty (TKA) for a stiff knee of patients with haemophilia (PWH) represents a challenge for orthopaedic surgeons for the difficulties of exposing the knee and high complication rate compared to a flexible knee. AIM: To optimize the surgical exposure in primary TKA for PWH and to propose a threshold angle of extension contracture in treating haemophilic knee joints, retrospectively. METHODS: Sixty-seven primary TKAs for PWH (mean age, 48 years) were performed, and incisional approaches to joint were standard (58 cases) and V-Y quadricepsplasty (V-Y) (9 cases). The decision of surgical approach was decided intraoperatively by two surgeons. Pre- and post-knee angles were evaluated in each group. Variables in the V-Y group were evaluated using univariate logistic regression analysis and receiver operating characteristic curve analysis. RESULTS: Univariate logistic regression analysis demonstrated that the preoperative range of motion (ROM) and flexion were significantly associated with V-Y. Threshold values of preoperative flexion and ROM resulting in V-Y using receiver operating characteristic analysis were 45° and 35°, respectively. CONCLUSIONS: Primary TKA for PWH using a standard approach may be performed before the stage preoperative flexion <45° and ROM <35°.

Evaluations of daily teriparatide using finite-element analysis over 12 months in rheumatoid arthritis patients.

INTRODUCTION: The objective of this study was to quantitatively evaluate the effects of daily teriparatide on rheumatoid arthritis patients using predicted bone strength (PBS) assessed by quantitative computed tomography-based finite-element analysis (QCT/FEA) and using bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DXA), and to prospectively investigate clinical determinants associated with PBS and BMD increases. MATERIALS AND METHODS: Participants comprised 39 patients (mean age, 69 years; disease activity score assessing 28 joints with CRP, 3.0; previous vertebral fractures, 82%) enrolled in this study. BMD by DXA and PBS by QCT/FEA of lumbar spine (LS) and proximal femur were measured at baseline, and after 6 and 12 months. In the groups showing increases in these values, variables that may have affected these increases were evaluated using univariate logistic regression analysis. RESULTS: Daily teriparatide treatment significantly increased not only LS BMD, but also LS PBS in RA patients with osteoporosis after both 6 and 12 months of treatment. Increases in N-terminal type I procollagen propeptide (PINP) at 1 and 3 months were significantly associated with increased LS PBS at 12 months according to univariate logistic regression analysis. The threshold value for increased PINP at 1 month for increased PBS at 12 months was 75 µg/L. CONCLUSIONS: Increased LS PBS at 12 months was predicted by increased PINP at 1 month from baseline.

Risk of deep venous thrombosis after total knee arthroplasty in patients with haemophilia A.

INTRODUCTION: Venous thromboprophylaxis remains controversial in patients with haemophilia undergoing major orthopaedic surgery, due to clotting factor replacement therapy to correct the patient's inherent haemostatic defect during procedure, at least in theory. We have previously reported that deep venous thrombosis (DVT) was not detected on ultrasonography (US) after total knee arthroplasty (TKA) in 36 Japanese patients with haemophilia. AIM: To evaluate the prevalence of DVT after TKA among haemophilic A patients using not only US, but also contrast-enhanced CT prospectively. METHODS: This study enrolled 11 TKAs in 11 Japanese patients with haemophilia A not having any history of inhibitor. A pneumatic compression device was used from the beginning of the operation until the patient could perform standing exercises (day 2). US of the lower extremities was performed before and after surgery (day 2) to detect DVT. Contrast-enhanced CT was performed after surgery (day 7) to detect VTE. D-dimer was measured at pre- and postoperative time. RESULTS: Mean (±standard deviation) age at the time of operation was 50.5 ± 12.3 years. DVT was not found on either pre- or postoperative examinations by US, but contrast-enhanced CT was detected DVT in two cases. No patients showed clinical signs for VTE during hospitalization, and no additional treatment for VTE. No episodes of unexpected bleeding were encountered. CONCLUSION: Contrast-enhanced CT detected DVT in 18% of haemophilia A patients who underwent TKA despite no detection of DVT on US. We must consider how to prevent and treat VTE in patients with haemophilia scheduled to undergo orthopaedic surgery.

Prediction of quadriceps strength recovery after anterior cruciate ligament reconstruction with a hamstring autograft: Decision tree analysis.

BACKGROUND: The wide variations in patient demographics and concomitant injuries make the prediction of which patients will regain strength quickly following anterior cruciate ligament (ACL) reconstruction challenging. This study aimed to identify the dominant factor affecting quadriceps strength recovery after ACL reconstruction with a hamstring tendon autograft and to construct a predictive model for quadriceps strength recovery using decision tree analysis. METHODS: Three hundred and eighty-six patients who underwent ACL reconstruction with a hamstring tendon autograft were included in this study. The isokinetic quadriceps strength at 60°/s was measured preoperatively and at 6 months after surgery. The quadriceps strength index (QSI) was calculated by normalising the peak torque of the involved leg with the uninvolved leg and multiplying it by 100. A stepwise multiple linear regression and a decision tree analysis were performed to assess whether or not the following parameters affect quadriceps strength recovery at 6 months: socio-demographic data and maximum isokinetic quadriceps strength. RESULTS: The preoperative QSI, age, and pre-injury Tegner activity scale were independently correlated with quadriceps strength recovery at 6 month after surgery. The decision tree analysis demonstrated that patients were expected to have a QSI ≥85% at 6 months after surgery if they met one of the following conditions: (1) age <23 years with a preoperative QSI ≥78.8%, (2) age ≥29 years with a preoperative QSI ≥98.0%, or (3) age <16 years with a preoperative QSI <58.5% and pre-injury Tegner activity scale ≥9. By contrast, patients ≥29 years with a preoperative QSI <98.0% were likely to achieve a quadriceps strength index <70% at 6 months after surgery. CONCLUSIONS: Based on the results of the decision tree analysis, younger patients could achieve good quadriceps recovery even if they have a lower preoperative QSI, whereas patients ≥29 years need a higher preoperative QSI to obtain good muscle recovery.

[The sequential therapy of romosozumab followed by denosumab for osteoporosis.]

Romosozumab is a bone-forming agent with a dual effect of increasing bone formation and decreasing bone resorption by inhibiting sclerostin. In the pivotal Fracture study in postmenopausal women with osteroposis(FRAME)and the extension trial, 12 months of romosozumab led to persistent fracture, especially new vertebral fracture, reduction benefit and ongoing BMD(bone mineral density)gains when follow 24 months of denosumab. The sequence therapy of romosozumab followed by denosumab may be a promising regimen for the treatment of osteoporosis.

Assessing joint destruction in the knees of patients with rheumatoid arthritis by using a semi-automated software for magnetic resonance imaging: therapeutic effect of methotrexate plus etanercept compared with methotrexate monotherapy.

OBJECTIVES: To evaluate the prevention of knee joint destruction and clinical efficacy of methotrexate (MTX) plus etanercept (ETN) compared with MTX monotherapy in patients with rheumatoid arthritis (RA) by using semi-automated software for magnetic resonance imaging (MRI) scan analysis. MATERIALS AND METHODS: This study enrolled patients with active moderate-to-severe RA who displayed an inadequate response to oral MTX at screening. Patients were assigned to receive either MTX plus ETN or MTX monotherapy (≥10 mg/week). The primary endpoint was the quantitative knee cartilage volume using our software developed for MRI scan analysis. RESULTS: A total of 18 female patients were enrolled in this study and allocated to the MTX + ETN group (n = 9) or the MTX monotherapy group (n = 9). At 52 weeks, the quantitative knee cartilage volume was significantly reduced compared with baseline in both groups (MTX plus ETN group: 2.3 ± 2.3 cm3; MTX monotherapy group: 2.4 ± 1.6 cm3); however, the difference was not significant. CONCLUSION: The semi-automated software for MRI scan analysis can reveal useful and potentially clinically important information about the characteristics of knee joint destruction in patients with RA.

Factors affecting quadriceps strength recovery after anterior cruciate ligament reconstruction with hamstring autografts in athletes.

PURPOSE: Patients typically return to sports activities 6-12 months after anterior cruciate ligament (ACL) reconstruction, and quadriceps strength has been used as one of the criteria to return to sports activities. The purpose of this study is to identify the factors that affect quadriceps strength recovery after ACL reconstruction with a hamstring tendon autograft 6 months after surgery. METHODS: Isokinetic quadriceps strength at 60°/s was measured preoperatively and 6 months after surgery in 193 athletes who underwent ACL reconstruction with a hamstring tendon autograft. The quadriceps strength index was calculated by normalizing the peak torque of the involved leg with the uninvolved leg. The subjects were divided into two groups according to the quadriceps strength index 6 months after surgery: at least 85 % (n = 84) or less than 85 % (n = 109). Multivariate logistic regression analysis and a receiver operating curve analysis were performed. RESULTS: The preoperative quadriceps strength index [odds ratio (OR) 1.02; 95 % confidence interval (CI) 1.01-1.03], age (OR 0.92; 95 % CI 0.86-0.98), sex (OR 2.45; 95 % CI 1.19-5.18), and knee pain (OR 0.17; 95 % CI 0.04-0.52) were independently associated with quadriceps strength recovery. The cut-off value of the preoperative quadriceps strength index was 70.2 % to obtain at least 85 % quadriceps strength index 6 months after surgery. CONCLUSION: To achieve sufficient quadriceps strength recovery at the timing of return to sports activities following ACL reconstruction using a hamstring tendon autograft, preoperative quadriceps strength, age, sex, and knee pain should be considered. LEVEL OF EVIDENCE: III.

Cycling Wheelchair Provides Enjoyable Pedaling Exercises with Increased Physiological Indexes.

The cycling wheelchair (CWC) can be used as a pedaling exercise machine. However, physiological indexes in the CWC at various pedaling rates and the difference between the CWC and the existing pedaling machines such as the portable ergometer (ERG) are unclear. The aim of this study was to measure physiological indexes in the CWC at various pedaling rates and compare the CWC to the ERG, focusing on psychological stress. The present non-randomized crossover study included ten healthy men (22.3 ± 1.2 years) who performed pedaling exercise with the CWC and the ERG. Both experiments were composed of three pedaling exercise sessions (40, 60, and 80 rpm). Physiological indexes, consisting of oxygen consumption, heart rate, perceived breathlessness and leg fatigue, and salivary amylase activity (SAA), an index of psychological stress, were measured. The metabolic equivalent (METs) and the rate of change in SAA from rest to immediately after each pedaling session (ΔSAA) were calculated. In the CWC, all physiological indexes significantly increased with pedaling rates. The METs were 2.2 ± 0.3, 2.7 ± 0.4, and 3.5 ± 0.4 at 40, 60, and 80 rpm, respectively. In comparison between the CWC and the ERG, ΔSAA was lower in the CWC than in the ERG at 60 and 80 rpm. Our results indicate that the CWC pedaling can provide low or moderate intensity exercises with adjusting pedaling rates and is less stressful than the ERG. Thus, the CWC is a useful pedaling machine to promote regular and enjoyable exercises.

The impact of joint disease on the Modified Health Assessment Questionnaire scores in rheumatoid arthritis patients: A cross-sectional study using the National Database of Rheumatic Diseases by iR-net in Japan.

OBJECTIVES: To investigate the effect of bilateral and unilateral joint disease on the Modified Health Assessment Questionnaire (MHAQ) scores and the differences in joint weighting in rheumatoid arthritis patients. METHODS: A total of 9212 subjects from the Japanese nationwide cohort database NinJa, 2011, were analyzed. The presence or absence of disease in each joint, including swelling and/or tenderness, was investigated. The correlations between bilateral and unilateral disease in each joint and MHAQ scores were investigated using multivariable logistic regression analysis. RESULTS: The patients' mean age and disease duration was 63.2 and 12.2 years, respectively. The Disease Activity Score-28 was 3.3. The odds ratios of physical impairment according to the MHAQ using multivariable logistic regression models for bilateral and unilateral joints, respectively, were: shoulder, 4.0 and 1.8; elbow, 2.6 and 1.8; wrist, 1.9 and 1.5; hip, 1.7 and 3.0; knee, 2.6 and 1.9; ankle, 2.3 and 2.0, finger, 1.4 and 1.2; and toe, 1.0 and 1.1. The shoulder, elbow, wrist, knee, and ankle had a significant effect on physical impairment. CONCLUSIONS: The MHAQ score was significantly affected by shoulder, elbow, wrist, knee, and ankle joint disease. Furthermore, bilateral disease tended to have a greater effect on physical impairment than unilateral disease.

[Anti-osteoporosis drugs based on the guidelines for the Prevention and Treatment of Osteoporosis (2011 edition) ].

The aim of osteoporosis treatment is to reduce fracture risk. Many kinds of anti-osteoporosis drugs are available in these days, and most of them increase bone mineral density and reduce the risk of fractures. Japanese 2011 guidelines for prevention and treatment of osteoporosis documents the recommendation level of each osteoporosis drugs. It is important to select drugs appropriate for each osteoporosis patient considering the mechanisms of drug action and their clinical efficiency.

Is polypharmacy a risk factor for aspiration pneumonia in older adults? A case-control study.

INTRODUCTION: The incidence of aspiration pneumonia and the number of medicines prescribed increase with older age. Many medicines pose a risk for aspiration pneumonia, especially those that decrease swallowing function. Older adults with polypharmacy often receive a combination of these medicines. This study aimed to clarify whether polypharmacy is a risk factor for aspiration pneumonia. METHODS: Older adults aged ≥ 65 years receiving oral medicines were included in this case-control study. Patients hospitalized for pneumonia served as the case group, and other age-matched hospitalized patients served as the control group. Patient data were collected retrospectively, and logistic regression analysis was performed using items that showed significant differences in the univariate analysis as explanatory variables. RESULTS: Logistic regression analysis revealed that the number of medicines was not a risk factor for aspiration pneumonia; however, it was associated with the Functional Oral Intake Scale score, male sex, body mass index, and number of comorbidities. CONCLUSION: Although polypharmacy is often defined only by the number of medicines, it is not a risk factor for aspiration pneumonia. A detailed comparison of prescription medicines between the pneumonia and non-pneumonia groups is necessary.

Association Between Psychological Readiness to Return to Sports at 3 Months Postoperatively and Risk of Second ACL Injury.

Background: Psychological readiness to return to sports (RTS) has been associated with second anterior cruciate ligament (ACL) injury. However, this relationship is controversial because covariates such as anatomic and knee function characteristics have not been adequately considered. Purpose/Hypothesis: To investigate whether psychological readiness in the early postoperative period can predict the occurrence of a second ACL injury within 24 months after primary ACL reconstruction (ACLR) using propensity score analysis. It was hypothesized that patients with high ACL-RSI after injury (ACL-RSI) scores at 3 months postoperatively would have a second ACL injury within the projected postoperative period. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 169 patients who underwent primary ACLR using hamstring tendon autografts between November 2017 and July 2021 and also underwent knee functional assessments at 3 months postoperatively. The ACL-RSI scale was used to assess psychological readiness for RTS. A second ACL injury was defined if ipsilateral or contralateral ACL injury was confirmed by examination within 24 months postoperatively. Based on a previous study showing that 65 was the highest cutoff value for the ACL-RSI score for RTS, we classified patients into 2 groups: those with high ACL-RSI scores (≥65; group H) and those with low ACL-RSI scores (<65; group L). We generated 1-to-1 matched pairs using propensity score analysis and used log-rank testing to compare the rate of second ACL injury between the 2 groups. Results: More patients returned to any sports activities within 12 months in group H than in group L (90% vs 73%; P = .03). A second ACL injury within 24 months postoperatively was identified in 7% of patients (13/169). The rate of second ACL injury was significantly higher in group H than in group L (17.6% vs 3.4%; P = .001). In 43 matched pairs extracted using propensity scoring, the rate of second ACL injury was also higher in group H than in group L (18.6% vs 4.7%; P = .04). Conclusion: Patients with a higher ACL-RSI score at 3 months exhibited a significantly higher incidence of second ACL injury within 24 months after primary ACLR.

[Rheumatoid arthritis and bone -periarticular and systemic bone loss-].

In rheumatoid arthritis (RA) , the osteoclast pathway is activated by an abnormal immune condition accompanied by chronic inflammation, resulting in periarticular osteoporosis and local bone destruction around joints. In addition, multiple factors including pharmacotherapies such as steroids, and reduced physical activity, lead to systemic osteoporosis. These conditions expose patients to increased fracture risk. In RA treatment, it is important to achieve suppression of fracture risk by controlling inflammation, which is associated with periarticular osteoporosis and bone destruction, using disease-modifying anti-rheumatic drugs or biologic agents and by improving systemic osteoporosis using anti-osteoporotic agents.

[Secondary osteoporosis or secondary contributors to bone loss in fracture. Therapeutic intervention of rheumatoid arthritis bone loss].

In rheumatoid arthritis (RA) , the osteoclast pathway is activated by abnormal immune conditions accompanied by chronic inflammation resulting in periarticular osteoporosis and local bone destruction around joints. In addition, multiple factors lead to systemic osteoporosis, including reduced physical activity and pharmacotherapies such as steroids. These conditions cause decreased bone mineral density and bone quality, and expose patients to an increased risk of fracture. When treating patients with RA osteoporosis, it is important to improve systemic osteoporosis using anti-osteoporotic agents, and to suppress fracture risk by controlling inflammation (which is associated with periarticular osteoporosis and bone destruction) with a combination of disease-modifying anti-rheumatic drugs or biological agents.

[Bone structure in rheumatoid arthritis].

In rheumatoid arthritis (RA) , the osteoclast pathway is activated by abnormal immune conditions accompanied by chronic inflammation, resulting in periarticular osteoporosis and local bone destruction around joints. In addition, multiple factors, including reduced physical activity and pharmacotherapies such as steroids, lead to systemic osteoporosis. These conditions cause decreasing bone mineral density and deterioration of bone quality, and expose patients to increased risk of fracture. Understanding the bone structures of RA and evaluating fracture risk are central to the treatment of RA.

Effect of high-intensity interval exercise on renal artery hemodynamics in healthy young adults.

BACKGROUND: High-intensity interval exercise is useful for sustained exercise; however, its effect on renal artery hemodynamics is unclear. This study aimed to evaluate changes in renal artery blood flow velocity due to high-intensity interval exercise. METHODS: Ten healthy adults (age, 23.5±1.2 years) completed high-intensity interval exercise and moderate-intensity continuous exercise protocols on separate days. The high-intensity interval exercise protocol (total duration, 26 min) comprised eight sets of high-intensity exercise sessions at 85% maximum oxygen uptake for 1 min, with intervals of 40% maximum oxygen uptake for 2 min between sets. The moderate-intensity continuous exercise protocol comprised 40 min of exercise at 40% maximum oxygen uptake. Renal artery blood flow velocity and natural log-transformed high frequency spectral power (an index of cardiac parasympathetic nervous system activity) were measured before and after exercise. Additionally, exercise enjoyment was measured using a questionnaire. RESULTS: Renal artery blood flow velocity did not significantly differ between protocols or timepoints for either protocol. However, the natural log-transformed high frequency spectral power was significantly lower with high-intensity interval exercise than with moderate-intensity continuous exercise (P<0.001, F=25.97) during exercise and at 10 min after exercise, and it did not return to pre-exercise levels with high-intensity interval exercise. Moreover, there was no significant difference in exercise enjoyment between the two protocols. CONCLUSIONS: In healthy young adults, high-intensity interval exercise reduces parasympathetic activity; however, it does not produce any significant changes in renal artery hemodynamics after exercise.