These findings suggest that, theoretically, exaggerated urinary loss of VDBP in T1D, particularly in persons with albuminuria, could contribute mechanistically to vitamin D deficiency in this disease.
OBJECTIVE -Dysregulation of matrix metalloproteinase (MMP)-2 may contribute pathologically to the development of diabetes complications, including diabetic retinopathy and coronary and peripheral arterial disease. Our objective was to explore whether systemic MMP-2 dysregulation could be demonstrated in type 1 diabetes and to determine how MMP-2 concentration relates to disease status.RESEARCH DESIGN AND METHODS -In this cross-sectional study, MMP-2 concentrations and MMP-2 activity were measured in plasma and timed urine samples from 93 type 1 diabetic and 50 healthy control subjects, aged 14 -40 years. Relationships between MMP-2 concentrations in these biological fluids and subject characteristics (sex, age, and duration of type 1 diabetes), indexes of glycemic control (A1C, fasting plasma glucose, and continuous glucose monitoring system average daily glucose), and measurements of renal function (urinary albumin excretion and glomerular filtration rate) were examined.RESULTS -Urine and plasma MMP-2 concentrations and plasma MMP-2 activity were all significantly elevated in type 1 diabetic subjects compared with those in control subjects. Urine MMP-2 concentrations, in particular, were correlated with several clinical parameters that infer increased risk for diabetic comorbidity and specifically for diabetic nephropathy, including higher A1C, longer duration of disease, evidence of renal hyperfiltration, and the presence of microalbuminuria.CONCLUSIONS -Urine and plasma MMP-2 concentrations are dysregulated in type 1 diabetes; urinary excretion of MMP-2, in particular, might provide a unique biomarker of diabetes-induced intrarenal pathologic processes. Diabetes Care 30:2321-2326, 2007M atrix metalloproteinases (MMPs) constitute a group of enzymes that hydrolyze protein components of the extracellular matrix (1). The subgroup of MMPs known as gelatinases, specifically gelatinase A (MMP-2) and gelatinase B (MMP-9) digest collagen, denatured collagens (i.e., gelatins), laminin, elastin, and fibronectin, among other substrates (2), and have been implicated in the pathological processes that contribute to fibrotic diseases, tumor progression, and inflammation (1,3,4).Dysregulation of gelatinase activity has also been implicated in the pathophysiology of diabetes complications. Specifically, gelatinase concentrations are increased in the systemic circulation ) and in the vitreous (MMP-2 [6] and MMP-9 [7]) of type 1 diabetic patients with diabetic retinopathy. Elevated retinal levels of MMP-2 and MMP-9 have also been demonstrated in an animal model of diabetic retinopathy (8). Increased circulating concentrations of MMP-2 have been observed in pediatric patients with type 1 diabetes who developed microangiopathy over a 5-year interval (9). Systemic concentrations of MMP-2 and MMP-9, in addition to gelatinase activity levels, are also increased in patients with type 2 diabetes and peripheral arterial disease (10).Data suggesting a link between MMP-2 dysregulation and diabetic nephropathy also exist but appear contra...
OBJECTIVEProteinuria is the hallmark of diabetic nephropathy; yet, glomerular histology does not fully explain mechanisms contributing to proteinuria. Our objective was to identify proteins in the urine of individuals with type 1 diabetes and microalbuminuria that might implicate a mechanistic pathway operative in proteinuria.RESEARCH DESIGN AND METHODSUsing a GeLC/MS platform proteomics approach, we compared the urine proteome from 12 healthy nondiabetic individuals, 12 subjects with type 1 diabetes yet normal urinary albumin excretion rates, and 12 subjects with type 1 diabetes and microalbuminuria (type 1 diabetes + microalbuminuria).RESULTSThe abundance of megalin and cubilin, two multiligand receptors expressed in kidney proximal tubule cells and involved with the reuptake of filtered albumin and megalin/cubilin ligands, was significantly increased in type 1 diabetes + microalbuminuria urine, compared with both nonalbuminuric groups.CONCLUSIONSAberrant shedding of megalin and cubilin could contribute to albuminuria in diabetes and to deficiency states of important vitamins and hormones.
Neutrophil gelatinase-associated lipocalin (NGAL), a biomarker of renal injury, can bind matrix metalloproteinase-9 (MMP-9) and inhibit its degradation, thereby sustaining MMP-9 proteolytic activity. MMP-9 is produced by renal podocytes, and podocyte MMP production can be modified by high ambient glucose levels. Moreover, dysregulation of MMP-9 activity, gene expression, or urine concentrations has been demonstrated in T2DM-associated nephropathy and in non-diabetic proteinuric renal diseases. Our objective was to determine whether NGAL/MMP-9 dysregulation might contribute to or serve as a biomarker of diabetic nephropathy in type 1 DM (T1DM). Plasma MMP-9, and urine NGAL and MMP-9 concentrations were measured in 121 T1DM and 55 control subjects and examined relative to indicators of glycemia, renal function, and degree of albuminuria. T1DM was associated with a significant increase in urinary excretion of both NGAL and MMP-9, and urine NGAL:Cr (NGAL corrected to urine creatinine) and urine MMP-9:Cr concentrations were highly correlated with each other. Both were also positively correlated with measurements of glycemic control and with albuminuria. Plasma MMP-9, urine MMP-9, and urine NGAL concentrations were significantly higher in females compared to males, and urine MMP-9:Cr concentrations displayed a menstrual cycle specific pattern. Increased urinary excretion of NGAL and MMP-9 supports a role for NGAL/MMP-9 dysregulation in renal dysfunction; moreover, genderspecific differences could support a gender contribution to pathological mechanisms or susceptibility for the development of renal complications in diabetes mellitus.
KeywordsEDTA; particle-based flow cytometry; sample processingThe authors appreciate the critical comments of Professor K. Jung, and agree with his demonstration, here and elsewhere (1,2), that differences between serum and plasma samples exist for measurement of MMP-9. We also agree, and have cautioned in our original manuscript, that plasma is the preferred clinical specimen for measurement of both MMP-8 and MMP-9 (3). Serum levels of these MMPs are very likely influenced by release of MMPs following degranulation of leukocytes and platelets during the ex vivo blood clotting process in the specimen collection tube (4). Finally, we agree that clinical research studies reporting on circulating MMP concentrations should clearly specify the sample collection methodology. Serum samples utilized in our analyses were prepared using "gold top" BD Vacutainers® (with clot activators and silicon coating, Becton Dickinson and Company, Franklin Lakes, USA) #367382; by centrifugation at 3400 rpm (2000×g) for 5 min.We would challenge, however, the inference that serum is never "appropriate" for the physiological ascertainment of MMP concentrations or that conclusions relative to MMP-9 can be generalized to all MMP measurements. For disease states characterized by cellular inflammatory responses, such as multiple sclerosis (5,6) and coronary artery disease (7-9), or malignant proliferation of inflammatory cell types such as multiple myeloma (10,11) and chronic lymphocytic leukemia (12,13), differences in serum measurements of MMPs have been detected and may provide a marker of pertinent intracellular protease activity. Alternatively, elevated concentrations of MMPs in serum might emanate from a circulating cell-type associated with a pathological condition. Moreover, recognizing that serum concentrations of MMPs have been assayed in disease states to identify clinically relevant or prognostic biomarkers of disease activation (10), we would suggest that both age-appropriate and specimen-appropriate reference ranges (or control data) be used in the interpretation of MMP concentrations in biological fluids. Finally, in our laboratory, Fluorokine® MultiAnalyte Profiling (F-MAP) methods have been used effectively for the simultaneous measurement of multiple MMPs in various biological fluids, including plasma, serum and urine (data not shown) and these measurements and their interrelationships may provide useful information.To demonstrate that differences in plasma vs. serum MMP-9 concentrations cannot necessarily be generalized to all MMPs, we offer some additional clinical data. We have recently assayed paired plasma (potassium EDTA BD Vacutainers®) and serum ("redtop" BD Vacutainers® with clot activator and silicon coated) specimens for MMP-1, -2, -3, -8 and -9 using F-MAP
Purpose To determine whether dysregulation of circulating concentrations of undercarboxylated osteocalcin (UC-OC) or GLA-carboxylated osteocalcin (GLA-OC) occurs in patients with type 1 diabetes, a condition of insulin deficiency without insulin resistance. Methods We measured serum concentrations of UC-OC and GLA-OC in 115 subjects with type 1 diabetes (T1D), ages 14–40 years, and in 55 age-matched healthy control subjects. Relationships between UC-OC and GLA-OC concentrations and patient characteristics (gender, age), indices of glycemic control (HbA1c, fasting plasma glucose, C-peptide concentration, 3-day average glucose measured by a continuous glucose sensor, total daily insulin dose) and circulating indices of skeletal homeostasis [Total calcium, 25-OH vitamin D, parathyroid hormone, IGF-I, type 1 collagen degradation fragments (CTX), adiponectin, leptin] were examined. Between group differences in the concentrations of UC-OC and GLA-OC were the main outcome measures. Results Although adiponectin levels were higher in the T1D group, between-group comparisons did not reveal statistically significant differences in concentration of UC-OC, GLA-OC, CTX or leptin between the T1D and control populations. Instead, by multivariate regression modeling, UC-OC was correlated with younger age (p<0.001), higher CTX (p<0.001), lower HbA1c (p=0.013) and higher IGF-I (p=0.086). Moreover, within the T1D subgroup, UC-OC was positively correlated with C-peptide: Glucose ratio (reflecting endogenous insulin secretion); with IGF-I (reflecting intra-portal insulin sufficiency); and with total daily insulin dose. Conclusions In T1D, UC-OC appears to correlate positively with markers of insulin exposure, either endogenously produced or exogenously administered.
Initiation of insulin pump therapy at diagnosis improved glycemic control, was well tolerated, and contributed to improved patient satisfaction with treatment. This study also suggests that earlier use of pump therapy might help to preserve residual β-cell function, although a larger clinical trial would be required to confirm this.
In recent months, the coronavirus pandemic has significantly affected almost every industry in the United States, including health care and higher education. Faculty and students at colleges and schools of pharmacy nationwide have needed to quickly adapt as the delivery of curricula has shifted to primarily online format. Additionally, experiential rotations have been significantly affected as practice settings such as hospitals and outpatient clinics have limited students’ interactions with patients or stopped allowing students on-site altogether. Our commentary will explore strategies that have been employed by experiential education coordinators and pharmacy preceptors from various settings to navigate experiential education during these difficult times while ensuring students successfully meet requirements for graduation. These will include descriptions of transitioning advanced pharmacy practice experiences (APPEs) to virtual format, how to safely involve students in the care of COVID-19 patients, and managing scheduling issues.
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