Relationship between tendon structure, stiffness, gait patterns and patient reported outcomes during the early stages of recovery after an Achilles tendon rupture.

After an Achilles tendon (AT) injury, the decision to return to full weightbearing for the practice of sports or strenuous activities is based on clinical features only. In this study, tendon stiffness and foot plantar pressure, as objective quantitative measures that could potentially inform clinical decision making, were repeatedly measured in 15 patients until 3 months after the AT rupture by using shear wave elastography (SWE) and wearable insoles, respectively. Meanwhile, patient reported outcomes assessing the impact on physical activity were evaluated using the Achilles Tendon Total Rupture Score (ATRS). At week-2 post-injury, stiffness of the injured tendon varied from 6.00 ± 1.62 m/s (mean ± SD) close to the rupture to 8.91 ± 2.29 m/s when measured more distally. While near complete recovery was observed in distal and middle regions at week-8, the shear wave velocity in the proximal region recovered to only 65% of the contralateral value at week-12. In a parallel pre-clinical study, the tendon stiffness measured in vivo by SWE in a rat model was found to be strongly correlated with ex vivo values of the Young's modulus, which attests to the adequacy of SWE for these measures. The insole derived assessment of the plantar pressure distribution during walking showed slight sub-optimal function of the affected foot at week-12, while the ATRS score recovered to a level of 59 ± 16. Significant correlations found between tendon stiffness, insole variables and distinct ATRS activities, suggest clinical relevance of tendon stiffness and foot plantar pressure measurements. These results illustrate how an alteration of the AT structure can impact daily activities of affected patients and show how digital biomarkers can track recovery in function over time.

Assessment of Low-Grade Focal Cartilage Lesions in the Knee With Sodium MRI at 7 T: Reproducibility and Short-Term, 6-Month Follow-up Data.

OBJECTIVES: Several articles have investigated potential of sodium (Na) magnetic resonance imaging (MRI) for the in vivo evaluation of cartilage health, but so far no study tested its feasibility for the evaluation of focal cartilage lesions of grade 1 or 2 as defined by the International Cartilage Repair Society. The aims of this study were to evaluate the ability of Na-MRI to differentiate between early focal lesions and normal-appearing cartilage, to evaluate within-subject reproducibility of Na-MRI, and to monitor longitudinal changes in participants with low-grade, focal chondral lesions. MATERIALS AND METHODS: Thirteen participants (mean age, 50.1 ± 10.9 years; 7 women, 6 men) with low-grade, focal cartilage lesions in the weight-bearing region of femoral cartilage were included in this prospective cohort study. Participants were assessed at baseline, 1 week, 3 months, and 6 months using morphological MRI at 3 T and 7 T, compositional Na-MRI at 7 T, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Na signal intensities corrected for coil sensitivity and partial volume effect (Na-cSI) were calculated in the lesion, and in weight-bearing and non-weight-bearing regions of healthy femoral cartilage. Coefficients of variation, repeated measures analysis of covariance models, and Pearson correlation coefficients were calculated to evaluate within-subject reproducibility as well as cross-sectional and longitudinal changes in Na-cSI values. RESULTS: The mean coefficients of variation of Na-cSI values between the baseline and 1-week follow-up were 5.1% or less in all cartilage regions. Significantly lower Na-cSI values were observed in lesion than in weight-bearing and non-weight-bearing regions at all time points (all P values ≤ 0.002). Although a significant decrease from baseline Na-cSI values in lesion was found at 3-month visit (P = 0.015), no substantial change was observed at 6 months. KOOS scores have improved in all subscales at 3 months and 6 months visit, with a significant increase observed only in the quality of life subscale (P = 0.004). CONCLUSIONS: In vivo Na-MRI is a robust and reproducible method that allows to differentiate between low-grade, focal cartilage lesions and normal-appearing articular cartilage, which supports the concept that compositional cartilage changes can be found early, before the development of advanced morphological changes visible at clinical 3-T MRI.

Effects of duloxetine on norepinephrine and serotonin transporter activity in healthy subjects.

Duloxetine selectively inhibits the serotonin (5-HT) and norepinephrine (NE) transporters (5-HTT and NET, respectively), as demonstrated in vitro and in preclinical studies; however, transporter inhibition has not been fully assessed in vivo at the approved dose of 60 mg/d. Here, the in vivo effects of dosing with duloxetine 60 mg once daily for 11 days in healthy subjects were assessed in 2 studies: (1) centrally (n = 11), by measuring concentrations of 5-hydroxyindoleacetic acid, 3,4-dihydroxyphenylglycol (DHPG), and NE in cerebrospinal fluid, and (2) versus escitalopram 20 mg/d (n = 32) in a 2-period crossover study by assessing the ΔDHPG/ΔNE ratio in plasma during orthostatic testing and by pharmacokinetic/pharmacodynamic modeling of reuptake inhibition using subjects' serum in cell lines expressing cloned human 5-HTT or NET. At steady state, duloxetine significantly reduced concentrations of DHPG and 5-hydroxyindoleacetic acid (P < 0.05), but not NE, in cerebrospinal fluid; DHPG was also decreased in plasma and urine. The ΔDHPG/ΔNE ratio in plasma decreased significantly more with duloxetine than escitalopram (65% and 21%, respectively; P < 0.0001). Ex vivo reuptake inhibition of 5-HTT was comparable (EC50 = 44.5 nM) for duloxetine and escitalopram, but duloxetine inhibited NET more potently (EC50 = 116 nM and 1044 nM, respectively). Maximal predicted reuptake inhibition for 5-HTT was 84% for duloxetine and 80% for escitalopram, and that for NET was 67% and 14%, respectively. In summary, duloxetine significantly affected 5-HT and NE turnover in the central nervous system and periphery; these effects presumably occurred via inhibition of reuptake by the 5-HTT and NET, as indicated by effects on functional reuptake inhibition ex vivo.

Evaluation of the effects of duloxetine and escitalopram on 24-hour heart rate variability: a mechanistic study using heart rate variability as a pharmacodynamic measure.

A decrease in heart rate variability (HRV) can indicate increased sympathetic nervous system activity and possibly increased norepinephrine levels. In this randomized, placebo- and escitalopram (ESC)-controlled, subject-blind, 2-period, crossover study, 26 healthy subjects 50 to 65 years old received duloxetine (DLX) 60 mg once daily or ESC 20 mg once daily for 11 days, each in sequential study periods separated by a 10-day or more washout period. Continuous electrocardiogram recordings were obtained by Holter monitoring (baseline, day 9, and day 10 of treatment). Duloxetine and ESC did not produce any clinically significant effects on standard measures of HRV, which included SD of normal R-R intervals and the root mean square difference among successive R-R normal intervals index values, mean change in SD of normal R-R intervals, and frequency domain analysis. However, treatment with DLX was associated with significantly less change from baseline in total beats per 24 hours than ESC, which was an unexpected finding compared with previous observations in which vital signs were measured at a specific time point while awake. In conclusion, in healthy adults exposed to DLX or ESC, no clinically significant effects on HRV were observed.

Effects of atomoxetine on the QT interval in healthy CYP2D6 poor metabolizers.

AIM: The effects of atomoxetine (20 and 60 mg twice daily), 400 mg moxifloxacin and placebo on QT(c) in 131 healthy CYP2D6 poor metabolizer males were compared. METHODS: Atomoxetine doses were selected to result in plasma concentrations that approximated expected plasma concentrations at both the maximum recommended dose and at a supratherapeutic dose in CYP2D6 extensive metabolizers. Ten second electrocardiograms were obtained for time-matched baseline on days -2 and -1, three time points after dosing on day 1 for moxifloxacin and five time points on day 7 for atomoxetine and placebo. Maximum mean placebo-subtracted change from baseline model-corrected QT (QT(c)M) on day 7 was the primary endpoint. RESULTS: QT(c)M differences for atomoxetine 20 and 60 mg twice daily were 0.5 ms (upper bound of the one-sided 95% confidence interval 2.2 ms) and 4.2 ms (upper bound of the one-sided 95% confidence interval 6.0 ms), respectively. As plasma concentration of atomoxetine increased, a statistically significant increase in QT(c) was observed. The moxifloxacin difference from placebo met the a priori definition of non-inferiority. Maximum mean placebo-subtracted change from baseline QT(c)M for moxifloxacin was 4.8 ms and this difference was statistically significant. Moxifloxacin plasma concentrations were below the concentrations expected from the literature. However, the slope of the plasma concentration-QT(c) change observed was consistent with the literature. CONCLUSION: Atomoxetine was not associated with a clinically significant change in QT(c). However, a statistically significant increase in QT(c) was associated with increasing plasma concentrations.

Efficacy and safety of exenatide once-weekly vs exenatide twice-daily in Asian patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: To compare safety and efficacy of the extended-release formulation exenatide once weekly (EQW) vs exenatide twice daily (EBID) for 26 weeks in type 2 diabetes patients from China, India, Japan, South Korea and Taiwan. MATERIALS AND METHODS: A randomized, comparator-controlled, open-label study included 681 patients with type 2 diabetes inadequately controlled (hemoglobin A1c [HbA1c] ≥7 and ≤11%) with oral antihyperglycemic medications (OAMs). Patients added 2 mg EQW or 10 µg EBID to current OAMs. Safety was re-evaluated 10 weeks after last treatment. RESULTS: EQW was superior to EBID on HbA1c measures at week 26 (Least-squares mean treatment difference: -0.31% [95% confidence interval -0.49, -0.14%]). More EQW-treated patients achieved target HbA1c ≤7.0% (P = 0.003), ≤6.5% (P < 0.001), or ≤6.0% (P = 0.003). Fasting serum glucose reductions were greater among EQW-treated patients (P < 0.001). Blood glucose profiles improved in both treatment groups (P < 0.001). Weight loss occurred with both treatments, but was greater with EBID. Adverse events (≥10%, either group) were nausea, injection-site induration, dyslipidemia and vomiting. Injection-site induration was more frequent with EQW, whereas nausea, vomiting and hypoglycemia were less frequent. One episode each of major hypoglycemia (EBID) and pancreatitis (EQW) were reported. CONCLUSION: In this population, EQW and EBID showed efficacious glucose and weight control; safety and tolerability were consistent with observations in non-Asian patients. This trial was registered with ClinicalTrials.gov (no. NCT00917267).

Safety of exenatide once weekly for 52 weeks in Japanese patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: An initial 26-week, randomized, open-label study compared the efficacy and safety of exenatide 10 mcg twice daily with exenatide 2 mg once weekly in Asian patients with type 2 diabetes who experienced inadequate glycemic control with oral antidiabetes medications. The aim of this study was to evaluate the safety of exenatide once weekly in Japanese patients, a subset of the initial patient population, who continued into this extension study for an additional 26 weeks of therapy on exenatide once weekly, followed by 10 weeks without exenatide once weekly. MATERIALS AND METHODS: Japanese patients initially assigned to exenatide twice daily (n = 62) switched to exenatide once weekly for the extended 26 weeks, and patients initially assigned to exenatide once weekly (n = 74) continued on this regimen for the remainder of the study (total treatment of 52 weeks). RESULTS: A total of 68% of patients reported one or more treatment-emergent adverse events during the extension period; the most common of these were nasopharyngitis (14%) and vomiting (6%). No major hypoglycemic episodes were reported. Improvements in glycated hemoglobin, fasting plasma glucose and postprandial glucose were maintained over 52 weeks of treatment. At week 52, bodyweight remained reduced from baseline. CONCLUSIONS: Exenatide once weekly added to oral antidiabetes medication was well tolerated in Japanese patients with type 2 diabetes, and was associated with glycemic control and weight loss through to 52 weeks, supporting the use of exenatide once weekly as an adjunctive treatment for type 2 diabetes in this patient population. The initial 26-week portion of this trial was registered with ClinicalTrials.gov (no. NCT00917267).

Safety of exenatide once weekly in patients with type 2 diabetes mellitus treated with a thiazolidinedione alone or in combination with metformin for 2 years.

BACKGROUND: Patients with type 2 diabetes mellitus are routinely treated with combinations of glucose-lowering agents. The adverse event (AE) profile and effects on glycemic control have not been assessed for the glucagon-like peptide-1 receptor agonist exenatide once weekly in combination with a thiazolidinedione (TZD) with or without metformin. OBJECTIVE: This study was conducted to examine the long-term safety profile and changes in glycemic control and weight for exenatide once weekly with TZD with or without metformin in patients with type 2 diabetes mellitus over 2 years. METHODS: In this single-arm, open-label trial with treatment up to 104 or 117 weeks, patients received 2 mg exenatide once weekly while continuing treatment with a TZD with or without metformin. Patients were either exenatide-naïve before this study or had previously received exenatide twice daily, which was discontinued on initiating exenatide once weekly. Patients were on a stable dosage of TZD (rosiglitazone or pioglitazone) and, if applicable, metformin. Treatment-emergent AEs were defined as those first occurring or worsening post baseline. Descriptive statistics were used for absolute and change-from-baseline data, and a one-sample t test for within-group change in glycosylated hemoglobin (HbA(1c)). RESULTS: Of 134 patients in the intent-to-treat population (baseline mean [SD] HbA(1c),7.2% [1.0%]), 44 were exenatide-naïve (baseline HbA(1c), 7.8% [1.0%]) and 90 switched from exenatide twice daily (baseline HbA(1c), 7.0% [0.8%]). Of intent-to-treat patients, 106 (79%) completed the final treatment visit (week 104 or week 117). The most common AEs were nausea (17% of patients) and injection-site nodule (12% of patients). Serious AEs were reported in 14% of patients and 5% withdrew because of a treatment-emergent AE. No identifiable pattern of serious AEs was observed. There were 4 reports of edema and no reports of heart failure. No major hypoglycemia was reported; minor hypoglycemia was reported in 4% of patients. Exenatide-naïve patients experienced mean (SE) HbA(1c) reductions of -0.7% (0.2%) and weight reductions of -2.7 (0.8) kg, whereas patients with prior exposure to exenatide twice daily experienced a reduction of -0.4% (0.1%) in HbA(1c) and no change in weight. CONCLUSIONS: Adverse events over 2 years were consistent with the reported safety profiles of exenatide once weekly and TZDs. Exenatide-naïve patients experienced improvements in HbA(1c) and weight, while patients with the benefit of prior exenatide therapy experienced an additional reduction from baseline in HbA(1c) and no additional change in weight after 2 years. ClinicalTrials.gov identifier: NCT00753896.

Effect of exenatide on cholecystokinin-induced gallbladder emptying in fasting healthy subjects.

Exenatide is a glucagon-like peptide-1 receptor agonist for the treatment of type 2 diabetes and has been shown to lower blood glucose through multiple mechanisms, including glucose-dependent insulin secretion, suppression of postprandial glucagon release and slowing of gastric emptying. The effects of exenatide on biliary motility are unknown. This study evaluated the effect of a single dose of exenatide on cholecystokinin (CCK)-induced gallbladder emptying. Healthy subjects participated in this randomized, 2-period, double-blind crossover study. Fasting subjects received a single subcutaneous injection of exenatide (10 µg) or placebo 60 min before CCK infusion. Gallbladder volume and ejection fraction (EF) were assessed by ultrasonography before, during, and after CCK infusion (0.003 µg/kg infused over 50 min at 2 mL/min). The diameters of the main pancreatic duct and common bile duct were measured sonographically at the same time points before, during, and following CCK infusion. Administration of exenatide did not affect pre-CCK infusion gallbladder volume or EF compared to placebo. During the CCK-infusion, the mean minimum gallbladder volume was similar for exenatide (13.68 mL) and placebo (11.05 mL) (least squares mean [LSM] difference of 2.62 mL; 95% confidence interval [CI], -0.53, 5.78), but the mean maximum EF was lower for exenatide (28.79%) versus placebo (46.13%) (LSM difference of -17.34%; 95% CI, -30.54, -4.13). Exenatide had no clinically significant effects on pancreatic or bile duct diameters. In conclusion, exenatide reduced CCK-induced gallbladder emptying compared with placebo in fasting healthy subjects.

Safety and efficacy of once-weekly exenatide compared with insulin glargine titrated to target in patients with type 2 diabetes over 84 weeks.

OBJECTIVE: We recently reported that after 26 weeks, exenatide once weekly (EQW) resulted in superior A1C reduction, reduced hypoglycemia, and progressive weight loss compared with daily insulin glargine (IG) in patients with type 2 diabetes who were taking metformin alone or with sulfonylurea. This 84-week extension study assessed the long-term safety and efficacy of EQW versus IG. RESEARCH DESIGN AND METHODS: This multicenter, open-label, randomized, two-arm, parallel trial assessed change in A1C, proportions of patients achieving A1C <7.0 and ≤6.5%, body weight, incidence of hypoglycemia, and overall safety. RESULTS: Of 415 patients who completed 26 weeks, 390 (194 EQW and 196 IG patients) entered the extension study. At 84 weeks, A1C decreased from baseline (8.3%) by -1.2% for EQW vs. -1.0% for IG (P = 0.029). The proportions of patients who achieved end point A1C targets <7.0 and ≤6.5% were 44.6% for EQW patients vs. 36.8% for IG patients (P = 0.084) and 31.3% for EQW patients vs. 20.2% for IG patients (P = 0.009), respectively. Patients taking EQW lost 2.1 kg of body weight, whereas those taking IG gained 2.4 kg (P < 0.001). Among patients taking metformin plus sulfonylurea, the incidence of minor hypoglycemia was 24% for EQW patients vs. 54% for IG patients (P < 0.001); among patients taking metformin alone, it was 8% for EQW patients vs. 32% for IG patients (P < 0.001). Among adverse events occurring in ≥5% of patients, diarrhea and nausea occurred more frequently (P < 0.05) in the EQW group than in the IG group (12 vs. 6% and 15 vs. 1%, respectively). CONCLUSIONS: After 84 weeks, patients treated with EQW continued to experience better glycemic control with sustained overall weight loss and a lower risk of hypoglycemia than patients treated with IG.

Evaluation of methods for achieving stable INR in healthy subjects during a multiple-dose warfarin study.

PURPOSE: No consistent method is available for finding stable warfarin maintenance doses and fast stabilization of international normalized ratio (INR) values among healthy subjects in experimental warfarin interaction studies. Using data from an earlier study that targeted a stable INR of 1.5-2.0 to test an interaction, we retrospectively evaluated potential dosing algorithms using all methods available to us to decrease the time needed for INR stabilization, which could be useful for future interaction studies in healthy subjects. METHODS: Published pharmacogenetic and clinical dosing algorithms used to initiate pharmacotherapy with warfarin were applied, predicted doses and actual doses were compared by regression analysis, and concentration-time profiles of S-warfarin were simulated using SimCYP® software. RESULTS: No demographic variables were significantly associated with time to reach a stable, low-intensity INR in this population of relatively young, healthy subjects. Predicted and actual doses were positively correlated for the pharmacogenetic algorithm, but not for the clinical algorithm. INR levels and S-warfarin concentrations were associated with CYP2C9 and VKORC1 genotypes. CONCLUSIONS: Induction to a pharmacodynamic steady state for warfarin for future multiple-dose warfarin drug-interaction studies in healthy volunteers may be predicted using a pharmacogenetic-based dosing algorithm. Simulations revealed that the desired subtherapeutic INR level may be achieved by reducing the predicted dose by approximately 15%. Further study is needed to assess the applicability of this approach to decrease attrition rates and the time needed to reach INR stabilization.

Systematic decrements in QTc between the first and second day of contiguous daily ECG recordings under controlled conditions.

BACKGROUND: Many thorough QT (TQT) studies use a baseline day and double delta analysis to account for potential diurnal variation in QTc. However, little is known about systematic changes in the QTc across contiguous days when normal volunteers are brought into a controlled inpatient environment. METHODS: Two separate crossover TQT studies included 2 days of no treatment lead-in days with ECG collection preceding periods of drug treatment . In the first study, there were two pairs of such contiguous days with 10 replicate electrocardiograms (ECGs) collected at six time points, and in the second study, there were four pairs of contiguous days with nine replicate ECGs collected at five time points. These lead-in day pairs provided the opportunity to evaluate any systematic changes across contiguous first and second days of an inpatient environment. Within-patient consistency of change across pairs of days as well as within day, diurnal variation could also be evaluated. RESULTS: Modest (4.2 ms [range 1.9-6.5 ms]) but consistent decreases (significant [P < 0.05] for all 32 comparisons) were observed (probability: ≤5.4 × 10(-16)). Although group behavior with respect to QTc was consistent, individual subjects demonstrated substantial variability across pairs of days. Evidence of diurnal variation was weak and inconsistent. Magnitude of any diurnal variation was less than magnitude of change across days. CONCLUSIONS: Subjects show a systematic decrease in QTc from first day to second day of inpatient status and do not demonstrate a significant diurnal pattern. The magnitude of this systematic change is sufficient to influence QTc study interpretation.

Effects of angiotensin-converting enzyme inhibition on transient ischemia: the Quinapril Anti-Ischemia and Symptoms of Angina Reduction (QUASAR) trial.

OBJECTIVES: We sought to determine whether angiotensin-converting enzyme inhibition (ACE-I) (i.e., quinapril) prevents transient ischemia (exertional and spontaneous) in patients with coronary artery disease (CAD). BACKGROUND: It is known that ACE-I reduces the risk of death, myocardial infarction (MI), and other CAD-related outcomes in high-risk patients. Numerous studies have confirmed that ACE-I improves coronary flow and endothelial function. Whether ACE-I also decreases transient ischemia is unclear, because no studies have been adequately designed or sufficiently powered to evaluate this issue. METHODS: Using a randomized, double-blinded, placebo-controlled, multicenter design, we enrolled 336 CAD patients with stable angina. None had uncontrolled hypertension, left ventricular (LV) dysfunction, or recent MI, and all developed electrocardiographic (ECG) evidence of ischemia during exercise. They were randomly assigned to one of two groups: 40 mg/day quinapril (n = 177) or placebo (n = 159) for 8 weeks. Patients then entered an additional eight-week treatment phase to examine the full dose range. Those assigned to 40 mg quinapril continued that dose and those assigned to placebo were titrated to 80 mg/day. Treadmill testing, the Seattle Angina Questionnaire, and ambulatory ECG monitoring were used to assess responses at baseline and at 8 and 16 weeks. RESULTS: The groups did not differ significantly at entry or in terms of indexes assessing myocardial ischemia at 8 or 16 weeks of treatment. In this low-risk population, ACE-I was not associated with serious adverse events. CONCLUSIONS: Our findings suggest short-term ACE-I in CAD patients without hypertension, LV dysfunction, or acute MI is not associated with significant effects on transient ischemia.