RESUMEN
Preclinical evidence demonstrates that senescent cells accumulate with aging and that senolytics delay multiple age-related morbidities, including bone loss. Thus, we conducted a phase 2 randomized controlled trial of intermittent administration of the senolytic combination dasatinib plus quercetin (D + Q) in postmenopausal women (n = 60 participants). The primary endpoint, percentage changes at 20 weeks in the bone resorption marker C-terminal telopeptide of type 1 collagen (CTx), did not differ between groups (median (interquartile range), D + Q -4.1% (-13.2, 2.6), control -7.7% (-20.1, 14.3); P = 0.611). The secondary endpoint, percentage changes in the bone formation marker procollagen type 1 N-terminal propeptide (P1NP), increased significantly (relative to control) in the D + Q group at both 2 weeks (+16%, P = 0.020) and 4 weeks (+16%, P = 0.024), but was not different from control at 20 weeks (-9%, P = 0.149). No serious adverse events were observed. In exploratory analyses, the skeletal response to D + Q was driven principally by women with a high senescent cell burden (highest tertile for T cell p16 (also known as CDKN2A) mRNA levels) in which D + Q concomitantly increased P1NP (+34%, P = 0.035) and reduced CTx (-11%, P = 0.049) at 2 weeks, and increased radius bone mineral density (+2.7%, P = 0.004) at 20 weeks. Thus, intermittent D + Q treatment did not reduce bone resorption in the overall group of postmenopausal women. However, our exploratory analyses indicate that further studies are needed testing the hypothesis that the underlying senescent cell burden may dictate the clinical response to senolytics. ClinicalTrials.gov identifier: NCT04313634 .
RESUMEN
CONTEXT: Reduced bone material strength index (BMSi) and increased cortical porosity (CtPo) have emerged as potentially contributing to fracture risk in type 2 diabetes mellitus (T2DM) patients. OBJECTIVE: To determine whether BMSi or CtPo are related to other diabetic complications. DESIGN: Cross-sectional observational study. SETTING: Subjects recruited from a random sample of southeast Minnesota residents. PARTICIPANTS: A total of 171 T2DM patients (mean age, 68.8 years) and 108 age-matched nondiabetic controls (mean age, 67.3 years). MAIN MEASURES: Bone material strength index was measured using microindentation, skin advanced glycation end-products (AGEs) measured using autofluorescence, high-resolution peripheral quantitative computed tomography at the distal radius and tibia, assessment of diabetic microvascular complications including urine microalbuminuria, retinopathy, neuropathy, and vascular disease (ankle brachial index and transcutaneous oxygen tension [TcPO2]). All analyses were adjusted for age, sex, and body mass index. RESULTS: Skin AGEs were negatively correlated with the BMSi in both T2DM (r = -0.30, P < 0.001) and control (r = -0.23, P = 0.020) subjects. In relating diabetic complications to CtPo, we found that T2DM patients with clinically significant peripheral vascular disease (TcPO2 ≤ 40 mm Hg) had higher (+21.0%, P = 0.031) CtPo at the distal tibia as compared to controls; in these subjects, CtPo was negatively correlated with TcPO2 at both the distal tibia (r = -0.39, P = 0.041) and radius (r = -0.41, P = 0.029). CONCLUSIONS: Our findings demonstrate that bone material properties are related to AGE accumulation regardless of diabetes status, while CtPo in T2DM patients is linked to TcPO2, a measure of microvascular blood flow.
Asunto(s)
Densidad Ósea/fisiología , Diabetes Mellitus Tipo 2/complicaciones , Angiopatías Diabéticas/epidemiología , Productos Finales de Glicación Avanzada/metabolismo , Fracturas Osteoporóticas/epidemiología , Anciano , Índice Tobillo Braquial , Estudios Transversales , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Angiopatías Diabéticas/diagnóstico , Angiopatías Diabéticas/fisiopatología , Femenino , Productos Finales de Glicación Avanzada/análisis , Humanos , Masculino , Persona de Mediana Edad , Fracturas Osteoporóticas/fisiopatología , Porosidad , Radio (Anatomía)/diagnóstico por imagen , Radio (Anatomía)/fisiopatología , Factores de Riesgo , Piel/química , Piel/metabolismo , Tibia/diagnóstico por imagen , Tibia/fisiopatología , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Advanced glycation end products (AGEs) are formed via the nonenzymatic glycation of sugars with amino acids. Two AGEs, Nε-(1-carboxymethyl)-L-Lysine (CML) and pentosidine, have been observed to be elevated in subjects suffering from a multitude of chronic disease states, and accumulation of these compounds may be related to the pathophysiology of disease progression and aging. METHODS: We describe here the development and validation of a specific and reproducible LC-MS/MS method to quantify CML and pentosidine in human serum with lower limits of quantitation of 75 ng/mL and 5 ng/mL, respectively. The analyte calibration curve exhibited excellent linearity at a range of 0-10 900 ng/mL for CML and 0-800 ng/mL for pentosidine. High-low linearity of 5 serum pairs was assessed, with a mean recovery of 103% (range 94-116%) for CML, and 104% (range 97-116%) for pentosidine. RESULTS: Serum concentrations of CML and pentosidine were quantified in 30 control and 30 subjects with chronic renal insufficiency. A significant increase in both analytes was observed in renal failure compared to control subjects (2.1-fold and 8.4-fold, respectively; P < 0.001 for both). In a separate cohort of 49 control versus 95 subjects with type 2 diabetes mellitus (T2DM), serum CML but not serum pentosidine, was significantly elevated in the T2DM patients, and CML was also correlated with glycemic control, as assessed by hemoglobin A1c (r = 0.34, P < 0.001). CONCLUSIONS: These mass spectroscopy-based assays for serum CML and pentosidine should be useful in accurately evaluating circulating levels of these key AGEs in various disease states.
Asunto(s)
Arginina/análogos & derivados , Diabetes Mellitus Tipo 2/sangre , Productos Finales de Glicación Avanzada/sangre , Lisina/análogos & derivados , Lisina/sangre , Espectrometría de Masas/métodos , Insuficiencia Renal/sangre , Arginina/sangre , Humanos , Reproducibilidad de los ResultadosRESUMEN
Bone remodeling consists of resorption by osteoclasts followed by formation by osteoblasts, and osteoclasts are a source of bone formation-stimulating factors. Here we utilize osteoclast ablation by denosumab (DMAb) and RNA-sequencing of bone biopsies from postmenopausal women to identify osteoclast-secreted factors suppressed by DMAb. Based on these analyses, LIF, CREG2, CST3, CCBE1, and DPP4 are likely osteoclast-derived coupling factors in humans. Given the role of Dipeptidyl Peptidase-4 (DPP4) in glucose homeostasis, we further demonstrate that DMAb-treated participants have a significant reduction in circulating DPP4 and increase in Glucagon-like peptide (GLP)-1 levels as compared to the placebo-treated group, and also that type 2 diabetic patients treated with DMAb show significant reductions in HbA1c as compared to patients treated either with bisphosphonates or calcium and vitamin D. Thus, our results identify several coupling factors in humans and uncover osteoclast-derived DPP4 as a potential link between bone remodeling and energy metabolism.
Asunto(s)
Huesos/metabolismo , Metabolismo Energético , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Anciano , Anciano de 80 o más Años , Animales , Remodelación Ósea , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Denosumab/administración & dosificación , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Dipeptidil Peptidasa 4/genética , Dipeptidil Peptidasa 4/metabolismo , Metabolismo Energético/efectos de los fármacos , Femenino , Humanos , Persona de Mediana Edad , Osteoblastos/efectos de los fármacos , Osteoclastos/efectos de los fármacos , Estudios Prospectivos , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismoRESUMEN
Central quantitative computed tomography (QCT) is increasingly used in clinical trials and practice to assess bone mass or strength and to evaluate longitudinal changes in response to drug treatment. Current studies utilize single-energy (SE) QCT scans, which may be confounded both by the amount of bone marrow fat at baseline and changes in marrow fat over time. However, the extent to which marrow fat changes either underestimate volumetric BMD (vBMD) measurements at baseline or under-/overestimate longitudinal changes in vivo in humans remains unclear. To address this issue, 197 early postmenopausal women [median age (IQR) 56.7 (54.4-58.7) years] underwent spine and hip QCT scans at baseline and 3â¯years using a 128-slice dual-source dual-energy (DE) scanner. The scans were analyzed as either SE scans (100â¯kVp) or DE scans (100â¯kVp and 140â¯kVp), with the latter accounting for bone marrow fat. At baseline, vertebral trabecular vBMD was (median) 17.6% lower (Pâ¯<â¯0.001) while femur neck (FN) cortical vBMD was only 3.2% lower (Pâ¯<â¯0.001) when assessed by SE vs DE scanning. SE scanning overestimated the 3â¯year rate of bone loss for trabecular bone at the spine by 24.2% (Pâ¯<â¯0.001 vs DE rates of loss) but only by 8.8% for changes in FN cortical vBMD (Pâ¯<â¯0.001 vs DE rates of loss). The deviation between SE and DE rates of bone loss in trabecular vBMD became progressively greater as the rate of bone loss increased. These findings demonstrate that SE QCT scans underestimate trabecular vBMD and substantially overestimate rates of age-related bone loss due to ongoing conversion of red to yellow marrow. Further, the greater the rate of bone loss, the greater the overestimation of bone loss by SE scans. Although our findings are based on normal aging, recent evidence from animal studies demonstrates that the skeletal anabolic drugs teriparatide and romosozumab may markedly reduce marrow fat, perhaps accounting for the disproportionate increases in trabecular vBMD by SE QCT as compared to dual-energy X-ray absorptiometry with these agents. As such, future studies using recently available DE scanning technology that has satisfactory precision and radiation exposure are needed to evaluate changes in trabecular vBMD independent of changes in marrow fat with aging and drugs that may alter marrow fat composition.