ABSTRACT
AIMS: Recently, dipeptidyl peptidase 3 (DPP3) has been discovered as the peptidase responsible for cleavage of angiotensin (1-7) [Ang (1-7)]. Ang (1-7) is part of the angiotensin-converting enzyme-Ang (1-7)-Mas pathway which is considered to antagonize the renin-angiotensin-aldosterone system (RAAS). Since DPP3 inhibits the counteracting pathway of the RAAS, we hypothesize that DPP3 might be deleterious in the setting of heart failure. However, no data are available on DPP3 in chronic heart failure. We therefore investigated the clinical characteristics and outcome related to elevated DPP3 concentrations in patients with worsening heart failure. METHODS AND RESULTS: Dipeptidyl peptidase 3 was measured in 2156 serum samples of patients with worsening heart failure using luminometric immunoassay (DPP3-LIA) by 4TEEN4 Pharmaceuticals GmbH, Hennigsdorf, Germany. Predictors of DPP3 levels were selected using multiple linear regression with stepwise backward selection. Median DPP3 concentration was 11.45 ng/mL with a range from 2.8 to 84.9 ng/mL. Patients with higher DPP3 concentrations had higher renin [78.3 (interquartile range, IQR 26.3-227.7) vs. 120.7 IU/mL (IQR 34.74-338.9), P < 0.001, for Q1-3 vs. Q4] and aldosterone [88 (IQR 44-179) vs. 116 IU/mL (IQR 46-241), P < 0.001, for Q1-3 vs. Q4] concentrations. The strongest independent predictors for higher concentration of DPP3 were log-alanine aminotransferase, log-total bilirubin, the absence of diabetes, higher osteopontin, fibroblast growth factor-23 and N-terminal pro-B-type natriuretic peptide concentrations (all P < 0.001). In univariable survival analysis, DPP3 was associated with mortality and the combined endpoint of death or heart failure hospitalization (P < 0.001 for both). After adjustment for confounders, this association was no longer significant. CONCLUSIONS: In patients with worsening heart failure, DPP3 is a marker of more severe disease with higher RAAS activity. It may be deleterious in heart failure by counteracting the Mas receptor pathway. Procizumab, a specific antibody against DPP3, might be a potential future treatment option for patients with heart failure.
Subject(s)
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Heart Failure , Renin-Angiotensin System , Aldosterone , Biomarkers , Heart Failure/drug therapy , HumansABSTRACT
BACKGROUND: Dipeptidyl peptidase 3 (DPP3) is a cytosolic enzyme involved in the degradation of various cardiovascular and endorphin mediators. High levels of circulating DPP3 (cDPP3) indicate a high risk of organ dysfunction and mortality in cardiogenic shock patients. METHODS: The aim was to assess relationships between cDPP3 during the initial intensive care unit (ICU) stay and short-term outcome in the AdrenOSS-1, a prospective observational multinational study in twenty-four ICU centers in five countries. AdrenOSS-1 included 585 patients admitted to the ICU with severe sepsis or septic shock. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by the Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use and need for renal replacement therapy. cDPP3 levels were measured upon admission and 24 h later. RESULTS: Median [IQR] cDPP3 concentration upon admission was 26.5 [16.2-40.4] ng/mL. Initial SOFA score was 7 [5-10], and 28-day mortality was 22%. We found marked associations between cDPP3 upon ICU admission and 28-day mortality (unadjusted standardized HR 1.8 [CI 1.6-2.1]; adjusted HR 1.5 [CI 1.3-1.8]) and between cDPP3 levels and change in renal and liver SOFA score (p = 0.0077 and 0.0009, respectively). The higher the initial cDPP3 was, the greater the need for organ support and vasopressors upon admission; the longer the need for vasopressor(s), mechanical ventilation or RRT and the higher the need for fluid load (all p < 0.005). In patients with cDPP3 > 40.4 ng/mL upon admission, a decrease in cDPP3 below 40.4 ng/mL after 24 h was associated with an improvement of organ function at 48 h and better 28-day outcome. By contrast, persistently elevated cDPP3 at 24 h was associated with worsening organ function and high 28-day mortality. CONCLUSIONS: Admission levels and rapid changes in cDPP3 predict outcome during sepsis. Trial Registration ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015.
Subject(s)
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/analysis , Mortality/trends , Sepsis/blood , Aged , Biomarkers/analysis , Biomarkers/blood , Chi-Square Distribution , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Female , Humans , Intensive Care Units/organization & administration , Intensive Care Units/statistics & numerical data , Male , Middle Aged , Multiple Organ Failure/blood , Multiple Organ Failure/physiopathology , Organ Dysfunction Scores , Proportional Hazards Models , Prospective Studies , Sepsis/mortality , Sepsis/physiopathology , Statistics, NonparametricABSTRACT
Sepsis is a global economic and health burden. Dipeptidyl peptidase 3 (DPP3) is elevated in the plasma of septic patients. The highest levels of circulating DPP3 (cDPP3) are found in non-survivor septic shock patients. The aim of this study was to evaluate the benefits of inhibiting cDPP3 by a specific antibody, Procizumab (PCZ), on cardiac function in an experimental model of sepsis, the caecal ligature and puncture (CLP) model. Rats were monitored by invasive blood pressure and echocardiography. Results are presented as mean ± SD, with p <0.05 considered significant. PCZ rapidly restored left ventricular shortening fraction (from 39 ± 4% to 51 ± 2% before and 30 min after PCZ administration (p = 0.004)). Cardiac output and stroke volume were higher in the CLP + PCZ group when compared to the CLP + PBS group (152 ± 33 mL/min vs 97 ± 25 mL/min (p = 0.0079), and 0.5 ± 0.1 mL vs 0.3 ± 1.0 mL (p = 0.009), respectively) with a markedly reduced plasma DPP3 activity (138 ± 70 U/L in CLP + PCZ group versus 735 ± 255 U/L (p = 0.048) in the CLP + PBS group). Of note, PCZ rapidly reduced oxidative stress in the heart of the CLP + PCZ group when compared to those of the CLP + PBS group (13.3 ± 8.2 vs 6.2 ± 2.5 UI, p = 0.005, 120 min after administration, respectively). Our study demonstrates that inhibition of cDPP3 by PCZ restored altered cardiac function during sepsis in rats.
Subject(s)
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/antagonists & inhibitors , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Enzyme Inhibitors/pharmacology , Heart/drug effects , Heart/physiopathology , Sepsis/blood , Sepsis/physiopathology , Animals , Disease Models, Animal , Hemodynamics/drug effects , Male , Proof of Concept Study , Rats , Rats, Wistar , Sepsis/enzymology , Systole/drug effects , Systole/physiologyABSTRACT
BACKGROUND: Dipeptidyl peptidase-3 (DPP3) is a metallopeptidase which cleaves bioactive peptides, notably angiotensin II, and is involved in inflammation regulation. DPP3 has been proposed to be a myocardial depressant factor and to be involved in circulatory failure in acute illnesses, possibly due to angiotensin II cleavage. In this study, we evaluated the association between plasmatic DPP3 level and outcome (mortality and hemodynamic failure) in severely ill burn patients. METHODS: In this biomarker analysis of a prospective cohort study, we included severely ill adult burn patients in two tertiary burn intensive care units. DPP3 was measured at admission (DPP3admin) and 3 days after. The primary endpoint was 90-day mortality. Secondary endpoints were hemodynamic failure and acute kidney injury (AKI). RESULTS: One hundred and eleven consecutive patients were enrolled. The median age was 48 (32.5-63) years, with a median total body surface area burned of 35% (25-53.5) and Abbreviated Burn Severity Index (ABSI) of 8 (7-11). Ninety-day mortality was 32%. The median DPP3admin was significantly higher in non-survivors versus survivors (53.3 ng/mL [IQR 28.8-103.5] versus 27.1 ng/mL [IQR 19.4-38.9]; p < 0.0001). Patients with a sustained elevated DPP3 had an increased risk of death compared to patients with high DPP3admin but decreased levels on day 3. Patients with circulatory failure had higher DPP3admin (39.2 ng/mL [IQR 25.9-76.1] versus 28.4 ng/mL [IQR 19.8-39.6]; p = 0.001) as well as patients with AKI (49.7 ng/mL [IQR 30.3-87.3] versus 27.6 ng/mL [IQR 19.4-41.4]; p = 0.001). DPP3admin added prognostic value on top of ABSI (added chi2 12.2, p = 0.0005), Sequential Organ Failure Assessment (SOFA) score at admission (added chi2 4.9, p = 0.0268), and plasma lactate at admission (added chi2 6.9, p = 0.0086) to predict circulatory failure within the first 48 h. CONCLUSIONS: Plasma DPP3 concentration at admission was associated with an increased risk of death, circulatory failure, and AKI in severely burned patients. Whether DPP3 plasma levels could identify patients who would respond to alternative hemodynamic support strategies, such as intravenous angiotensin II, should be explored.
Subject(s)
Acute Kidney Injury/blood , Burns/complications , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/analysis , Patient Admission/statistics & numerical data , Shock/blood , Aged , Burns/blood , Burns/physiopathology , Cohort Studies , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Female , Humans , Male , Middle Aged , Prognosis , Prospective Studies , Risk Factors , Severity of Illness IndexABSTRACT
BACKGROUND: The neuronal ceroid lipofuscinosis 2 (NCL2) or classic late-infantile neuronal ceroid lipofuscinosis (LINCL) is a neurogenetic disorder caused by mutations in the TPPI gene, which codes for the lysosomal tripeptidyl peptidase 1 (TPPI) EC 3.4.14.9. Loss of functional TPPI activity results in progressive visual and neurological symptoms starting at around 1-2 years of age causing early death. METHODS: We report a DBS-based TPPI assay that cleaves a synthetic tetrapeptide substrate generating a product that is detected by HPLC. Probands and carriers were identified with 100% accuracy (7 probands, 30 carriers, 13 controls). RESULTS: The assay detected a single TPPI activity at a lower pH towards the substrate tested. TPPI activity measurable when extracted at lower pH while inactive at neutral pH showed steady increase for at least 8 h incubation. No loss in TPPI activity was observed when DBS were stored for at least 2 weeks either in freezer, refrigerator, room temperature or 42 °C. CONCLUSION: A sequence variant causing Arg339Gln substitution in a proband had 12% TPPI. TPPI activity can be reliably measured in DBS, giving an opportunity to diagnose NCL2 at birth and refer patients for enzyme replacement or other therapies for earliest intervention, or alternatively offers a second-tier confirmatory test.
Subject(s)
Aminopeptidases/metabolism , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/metabolism , Dried Blood Spot Testing , Neuronal Ceroid-Lipofuscinoses/blood , Neuronal Ceroid-Lipofuscinoses/diagnosis , Serine Proteases/metabolism , Aminopeptidases/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Humans , Neuronal Ceroid-Lipofuscinoses/enzymology , Serine Proteases/blood , Tripeptidyl-Peptidase 1ABSTRACT
Anti-dipeptidyl-peptidase-like protein 6 (DPPX) encephalitis is a rare type of autoimmune encephalitis. We present a case of a 72-year-old male with anti-DPPX encephalitis who developed rapidly progressive cognitive decline, psychiatric and sleep problems, severe abdominal pain and diarrhea. Antibodies against DPPX were positive both in serum and cerebrospinal fluid. 18F-FDG PET-MR imaging indicated hypometabolism in the bilateral temporal lobes and thalamus. No related tumors were found, and the patient responded to immunotherapy without relapse at the 3-year follow-up. The present case enriches the understanding of the clinical, imaging manifestations and prognosis of anti-DPPX encephalitis.
Subject(s)
Autoantibodies/blood , Dementia/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Disease Progression , Encephalitis/blood , Nerve Tissue Proteins/blood , Potassium Channels/blood , Sleep Initiation and Maintenance Disorders/blood , Aged , Dementia/complications , Dementia/diagnostic imaging , Encephalitis/complications , Encephalitis/diagnostic imaging , Humans , Male , Remission Induction , Sleep Initiation and Maintenance Disorders/complications , Sleep Initiation and Maintenance Disorders/diagnostic imagingABSTRACT
AIMS: Dipeptidyl peptidase 3 (DPP3) is a protease involved in the degradation of cardiovascular mediators. Its administration has been shown to be associated with impaired cardiac contraction and kidney haemodynamics while its inhibition restored cardiac contraction in a pre-clinical model of severe heart failure in mice. Circulating DPP3 (cDPP3) was found to be elevated in shock. The present study aims to assess the association between cDPP3 and worsening haemodynamics, namely refractory shock, in a cohort of cardiogenic shock (CS). METHODS AND RESULTS: This is an ancillary study of OptimaCC, a prospective, double-blind, multicentre, randomized study assessing efficacy and safety of catecholamines in 57 patients with CS after acute myocardial infarction. cDPP3 was measured in plasma at inclusion, 24 h, 48 h, and 72 h, and haemodynamic and biological parameters were recorded at inclusion. cDPP3 values were higher in refractory CS than non-refractory CS at inclusion (median [interquartile range]; 76.1 [37.9-238.7] ng/mL vs. 32.8 [23.9-47.6] ng/mL, P = 0.014), at 24 h (P < 0.001) and up to 48 h (P = 0.027). Furthermore, cDPP3 at inclusion discriminated CS patients who did develop refractory shock vs. non-refractory with an area under the curve of 0.73 (95% confidence interval [CI] 0.55-0.92). The high cDPP3 group (cDPP3 ≥59.1 ng/mL) at inclusion had a higher Simplified Acute Physiology Score II (SAPS II), lower cardiac index and lower estimated glomerular filtration rate. More importantly, in CS patients with high cDPP3 at inclusion, those who rapidly decreased cDPP3 at 24 h exhibited a striking reduction in the occurrence of refractory shock and death. CONCLUSION: In CS patients, cDPP3 gives an early prediction of outcome, including development of refractory status and/or survival. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov Identifier NCT01367743.
Subject(s)
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Heart Failure , Shock, Cardiogenic/diagnosis , Double-Blind Method , Hemodynamics , Humans , Prospective Studies , Shock, Cardiogenic/bloodABSTRACT
AIMS: Acute heart failure is a high mortality disease and its pathophysiology is not completely understood. Dipeptidyl peptidase 3 (DPP3) is a cytosolic enzyme involved in angiotensin II and enkephalins cleavage. The aim of this study was to investigate the association of circulating DPP3 (cDPP3) levels and mortality in cardiogenic shock patients and to determine the effects of high cDPP3 on organ function in a heart failure (HF) model in mice. METHODS AND RESULTS: cDPP3 was measured in 174 patients in cardiogenic shock and high cDPP3 levels were associated with an increased short-term mortality risk (standardized hazard ratio: 1.4 (1.1-1.8)) and severe organ dysfunction. Additionally, a rapid decrease in cDPP3 in cardiogenic shock patients within 24 h of admission was associated with a favourable outcome. This study showed that injection of DPP3 induced myocardial depression (-10 ± 2% of shortening fraction) and impaired kidney haemodynamics (+0.30 ± 0.02 of renal resistive index) in healthy mice. cDPP3 inhibition by Procizumab, a specific antibody directed against cDPP3, promptly normalized cardiac function and kidney haemodynamics in an acute heart failure mouse model, with a marked reduction in oxidative stress and inflammatory signalling. CONCLUSION: Our study demonstrated cDPP3 is a newly discovered myocardial depressant factor, the levels of which at admission are associated with mortality in severe HF patients. Furthermore, inhibition of cDPP3 by Procizumab improved haemodynamics in a mouse model of HF. Our results suggest that DPP3 could be a new biomarker and biotarget for severe HF.
Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/antagonists & inhibitors , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Heart Failure , Animals , Anti-Arrhythmia Agents , Biomarkers , Heart Failure/drug therapy , Heart Failure/mortality , Hemodynamics/drug effects , Humans , MiceABSTRACT
BACKGROUND: The ubiquitously expressed dipeptidyl peptidase 3 (DPP3) is involved in protein metabolism, blood pressure regulation, and pain modulation. These diverse functions of DPP3 are attributed to the degradation of bioactive peptides like angiotensin II. However, because of limitations in currently available assays for determination of active DPP3 in plasma, the exact physiological function of DPP3 and its role in the catabolism of bioactive peptides is understudied. Here, we developed 2 assays to specifically detect and quantify DPP3 protein and activity in plasma and validated DPP3 quantification in samples from critically ill patients. METHODS: Assay performance was evaluated in a sandwich-type luminometric immunoassay (LIA) and an enzyme capture activity assay (ECA). DPP3 plasma concentrations and activities were detected in a healthy, population-based cohort and in critically ill patients suffering from severe sepsis and septic shock. RESULTS: The DPP3-LIA and DPP3-ECA show an almost ideal correlation and very similar and robust performance characteristics. DPP3 activity is detectable in plasma of predominantly healthy subjects with a mean (±SD) of 58.6 (±20.5) U/L. Septic patients show significantly increased DPP3 plasma activity at hospital admission. DPP3 activities further increase in patients with more severe conditions and high mortality risk. CONCLUSION: We developed 2 highly specific assays for the detection of DPP3 in plasma. These assays allow the use of DPP3 as a biomarker for the severity of acute clinical conditions and will be of great value for future investigations of DPP3's role in bioactive peptide degradation in general and the angiotensin II pathway in specific.
Subject(s)
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases , Immunoassay/methods , Sepsis/blood , Shock, Septic/blood , Biomarkers/analysis , Biomarkers/blood , Critical Illness/mortality , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/analysis , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Humans , Peptides/metabolism , Predictive Value of Tests , Reproducibility of Results , Risk Assessment/methodsABSTRACT
PURPOSE: CLN2 disease is a genetic disorder caused by dysfunction of the lysosomal enzyme tripeptidyl peptidase 1 (TPP1) that belongs to the neuronal ceroid lipofuscinoses (NCL) and leads to epilepsy, dementia, and death in young persons. CLN2 disease has recently become treatable by enzyme replacement, which can only be effective when the disease is diagnosed early. We have investigated the reliability of a test for TPP1 deficiency in dried blood specimens (DBS) to detect CLN2 disease. RESULTS: During a 12-year period we have received 3882 samples for testing TPP1. Quality of samples was checked by measuring two additional lysosomal enzyme activities. For 50 samples with subnormal TPP1 activity and good sample quality, we obtained adequate clinical and molecular genetic data. All 50 patients had doubtless evidence of CLN2 disease (including seven atypical patients) as shown by clinical findings and the presence of known pathogenic CLN2 variants. Our institution is a major reference center for NCL, and we have never received information that a patient with a normal DBS test was later diagnosed with CLN2 disease. CONCLUSIONS: We consider our TPP1 test on DBS to be a reliable, convenient and inexpensive tool for a first diagnostic step in suspected CLN2 disease.
Subject(s)
Aminopeptidases/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Dried Blood Spot Testing/methods , Fluorometry/methods , Neuronal Ceroid-Lipofuscinoses/blood , Neuronal Ceroid-Lipofuscinoses/enzymology , Serine Proteases/blood , Female , Humans , Male , Neuronal Ceroid-Lipofuscinoses/genetics , Phenotype , Time Factors , Tripeptidyl-Peptidase 1ABSTRACT
We first characterized PPT1 and TPP1 enzymes in dried blood spots (DBS), plasma/serum, and leukocytes/lymphocytes using neuronal ceroid lipofuscinosis (NCL) 1 and 2 patients and control subjects. PPT1 enzyme had only one acid form in control DBS, plasma/serum, and leukocytes/lymphocytes and showed deficient activities in these samples from NCL 1 patients. Conversely, TPP1 enzymes in control DBS and leukocytes/lymphocytes consisted of two forms, an acidic form and a neutral form, whereas serum TPP1 enzyme had only a neutral form. In control subjects, the optimal pH of PPT1 enzyme in DBS, plasma/serum, and leukocytes/lymphocytes was 4.5 to 5.0 in the acidic form, whereas TPP1 enzyme in control DBS and leukocytes/lymphocytes was pHâ¯4.5 and 6.5, respectively. In NCL 1 and 2, both PPT1 and TPP1 enzyme activities in DBS, plasma, and leukocytes/lymphocytes were markedly reduced in acidic pH, whereas heterozygotes of NCL 1 and 2 in the acidic form showed intermediate activities between patients and control subjects. In neutral conditions, pHâ¯6.0, the PPT1 enzyme activities in NCL 1 patients showed rather higher residual activities and intermediate activities in heterozygotes in NCL 1, which was probably caused by mutated proteins in three cases with NCL 1 patients. TPP1 enzyme activities at neutral pHâ¯6.5 to 7.0 in DBS and leukocytes/lymphocytes showed higher enzyme activities in NCL 2 patients and heterozygotes. The reason for the increases of neutral TPP1 enzyme activities at pHâ¯6.5 to 7.0 in NCL 2 DBS and leukocytes/lymphocytes, is obscure, but possibly caused by secondary activation of neutral TPP1 enzyme due to the absence of the acidic form. Interestingly, TPP1 activity in serum only consisted of a neutral form, no acidic form, and was not deficient in any NCL 2 patient. Therefore, we can diagnose NCL 1 patients by plasma/serum enzyme assay of PPT1, but not diagnose NCL 2 by serum TPP1 enzyme assay. A pilot study of newborn screening of NCL 1 and 2 has been established by more than 1000 newborn DBS assays. Using this assay system, we will be able to perform newborn screening of NCL 1 and 2 by DBS.
Subject(s)
Aminopeptidases/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Leukocytes/chemistry , Membrane Proteins/blood , Neonatal Screening/methods , Neuronal Ceroid-Lipofuscinoses/diagnosis , Serine Proteases/blood , Thiolester Hydrolases/blood , Adult , Child , Child, Preschool , Dried Blood Spot Testing/methods , Female , Humans , Hydrogen-Ion Concentration , Infant, Newborn , Male , Mutation , Pilot Projects , Tripeptidyl-Peptidase 1ABSTRACT
Neuronal ceroid lipofuscinoses (NCLs) are a heterogeneous group of lysosomal storage disorders. NCLs include the rare autosomal recessive neurodegenerative disorder neuronal ceroid lipofuscinosis type 2 (CLN2) disease, caused by mutations in the tripeptidyl peptidase 1 (TPP1)/CLN2 gene and the resulting TPP1 enzyme deficiency. CLN2 disease most commonly presents with seizures and/or ataxia in the late-infantile period (ages 2-4), often in combination with a history of language delay, followed by progressive childhood dementia, motor and visual deterioration, and early death. Atypical phenotypes are characterized by later onset and, in some instances, longer life expectancies. Early diagnosis is important to optimize clinical care and improve outcomes; however, currently, delays in diagnosis are common due to low disease awareness, nonspecific clinical presentation, and limited access to diagnostic testing in some regions. In May 2015, international experts met to recommend best laboratory practices for early diagnosis of CLN2 disease. When clinical signs suggest an NCL, TPP1 enzyme activity should be among the first tests performed (together with the palmitoyl-protein thioesterase enzyme activity assay to rule out CLN1 disease). However, reaching an initial suspicion of an NCL or CLN2 disease can be challenging; thus, use of an epilepsy gene panel for investigation of unexplained seizures in the late-infantile/childhood ages is encouraged. To confirm clinical suspicion of CLN2 disease, the recommended gold standard for laboratory diagnosis is demonstration of deficient TPP1 enzyme activity (in leukocytes, fibroblasts, or dried blood spots) and the identification of causative mutations in each allele of the TPP1/CLN2 gene. When it is not possible to perform both analyses, either demonstration of a) deficient TPP1 enzyme activity in leukocytes or fibroblasts, or b) detection of two pathogenic mutations in trans is diagnostic for CLN2 disease.
Subject(s)
Aminopeptidases/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Early Diagnosis , Neuronal Ceroid-Lipofuscinoses/blood , Serine Proteases/blood , Aminopeptidases/genetics , Brain/physiopathology , Child, Preschool , Dementia/complications , Dementia/physiopathology , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/genetics , Dried Blood Spot Testing , Enzyme Replacement Therapy , Female , Humans , Language Development Disorders/complications , Language Development Disorders/physiopathology , Leukocytes/enzymology , Male , Mutation , Neuronal Ceroid-Lipofuscinoses/complications , Neuronal Ceroid-Lipofuscinoses/genetics , Neuronal Ceroid-Lipofuscinoses/physiopathology , Phenotype , Serine Proteases/genetics , Tripeptidyl-Peptidase 1ABSTRACT
OBJECTIVE: To characterize pathogenic effects of antibodies to dipeptidyl-peptidase-like protein 6 (DPPX), a subunit of Kv4.2 potassium channels, on gut and brain neurons. METHODS: We identified a new patient with anti-DPPX encephalitis and analyzed the effects of the patient's serum and purified immunoglobulin G (IgG), and of serum of a previous patient with anti-DPPX encephalitis, on the activity of enteric neurons by voltage-sensitive dye imaging in guinea pig myenteric and human submucous plexus preparations. We studied the subcellular localization of DPPX by immunocytochemistry in cultured murine hippocampal neurons using sera of 4 patients with anti-DPPX encephalitis. We investigated the influence of anti-DPPX-containing serum and purified IgG on neuronal surface expression of DPPX and Kv4.2 by immunoblots of purified murine hippocampal neuron membranes. RESULTS: The new patient with anti-DPPX encephalitis presented with a 2-month episode of diarrhea, which was followed by tremor, disorientation, and mild memory impairment. Anti-DPPX-IgG-containing sera and purified IgG increased the excitability and action potential frequency of guinea pig and human enteric nervous system neurons. Patient sera revealed a somatodendritic and perisynaptic neuronal surface staining that colocalized with the signal of commercial anti-DPPX and Kv4.2 antibodies. Incubation of hippocampal neurons with patient serum and purified IgG resulted in a decreased expression of DPPX and Kv4.2 in neuronal membranes. CONCLUSIONS: Hyperexcitability of enteric nervous system neurons and downregulation of DPPX and Kv4.2 from hippocampal neuron membranes mirror the clinical phenotype of patients with anti-DPPX encephalitis and support a pathogenic role of anti-DPPX antibodies in anti-DPPX encephalitis.
Subject(s)
Antibodies, Anti-Idiotypic/blood , Brain/pathology , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Encephalitis/blood , Myenteric Plexus/pathology , Nerve Tissue Proteins/blood , Neurons/pathology , Potassium Channels/blood , Aged , Animals , Antibodies, Anti-Idiotypic/administration & dosage , Brain/drug effects , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/administration & dosage , Encephalitis/diagnosis , Guinea Pigs , Humans , Immunoglobulin G/administration & dosage , Immunoglobulin G/blood , Male , Mice , Myenteric Plexus/drug effects , Nerve Tissue Proteins/administration & dosage , Neurons/drug effects , Potassium Channels/administration & dosage , RatsABSTRACT
The purpose of this article is to characterize skin lesions in cynomolgus monkeys following vildagliptin (dipeptidyl peptidase-4 inhibitor) treatment. Oral vildagliptin administration caused dose-dependent and reversible blister formation, peeling and flaking skin, erosions, ulcerations, scabs, and sores involving the extremities at ≥5 mg/kg/day and necrosis of the tail and the pinnae at ≥80 mg/kg/day after 3 weeks of treatment. At the affected sites, the media and the endothelium of dermal arterioles showed hypertrophy/hyperplasia. Skin lesion formation was prevented by elevating ambient temperature. Vildagliptin treatment also produced an increase in blood pressure and heart rate likely via increased sympathetic tone. Following treatment with vildagliptin at 80 mg/kg/day, the recovery time after lowering the temperature in the feet of monkeys and inducing cold stress was prolonged. Ex vivo investigations showed that small digital arteries from skin biopsies of vildagliptin-treated monkeys exhibited an increase in neuropeptide Y-induced vasoconstriction. This finding correlated with a specific increase in NPY and in NPY1 receptors observed in the skin of vildagliptin-treated monkeys. Present data provide evidence that skin effects in monkeys are of vascular origin and that the effects on the NPY system in combination with increased peripheral sympathetic tone play an important pathomechanistic role in the pathogenesis of cutaneous toxicity.
Subject(s)
Adamantane/analogs & derivatives , Neuropeptide Y/adverse effects , Nitriles/adverse effects , Pyrrolidines/adverse effects , Skin Diseases/pathology , Skin/drug effects , Vascular System Injuries/pathology , Adamantane/administration & dosage , Adamantane/adverse effects , Administration, Oral , Animals , Blood Pressure/drug effects , Cold Temperature , Dipeptidases/blood , Dipeptidyl Peptidase 4/metabolism , Dipeptidyl-Peptidase IV Inhibitors , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Macaca fascicularis , Neuropeptide Y/administration & dosage , Nitriles/administration & dosage , Norepinephrine/urine , Pyrrolidines/administration & dosage , Skin/pathology , Skin Diseases/chemically induced , Stress, Physiological , Vascular System Injuries/chemically induced , Vasoconstriction/drug effects , VildagliptinABSTRACT
The effects of noncompetitive prolyl endopeptidase inhibitor benzyloxycarbonyl-methionyl-2(S)-cyanopyrrolidine were studied in rats with the experimental dopamine deficiency-dependent depressive syndrome induced by systemic injections of a pre-neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin for 14 days. The inhibitor (3.0 mg/kg, i.p., 30 min before pre-neurotoxin injection on days 8-14) alleviated depression symptoms and promoted normalization of behavioral activity after drug withdrawal. The obtained data reflected therapeutic antidepressant properties of inhibitor for prolyl endopeptidase benzyloxycarbonyl-methionyl-2(S)-cyanopyrrolidine.
Subject(s)
Behavior, Animal/drug effects , Depressive Disorder/drug therapy , Dopamine/deficiency , Methionine/analogs & derivatives , Pyrrolidines/therapeutic use , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/administration & dosage , Animals , Anxiety/metabolism , Body Weight , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/antagonists & inhibitors , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/metabolism , Male , Methionine/pharmacology , Methionine/therapeutic use , Prolyl Oligopeptidases , Pyrrolidines/pharmacology , Rats , Rats, Wistar , Serine Endopeptidases/drug effects , Serine Endopeptidases/metabolism , Sucrose/metabolismABSTRACT
Egypt has the highest prevalence of hepatitis C virus infection worldwide. CXCL10 is a potent chemoattractant that directs effector lymphocytes to sites of inflammation. It has been reported that plasma CXCL10 is processed by dipeptidylpeptidase IV (DPPIV) thus leading to the generation of an antagonist form. Using Luminex-based immunoassays we determined the concentration of different forms of CXCL10 (total, agonist, and antagonist). We also evaluated plasma soluble DPPIV (sDPPIV) concentration and plasma dipeptidylpeptidase (DPP) activity. Using flow cytometry and immunohistochemistry, we analyzed the distribution of lymphocyte subsets. Plasma CXCL10 was elevated in chronic HCV patients, however the agonist form was undetectable. Increased sDPPIV concentration and DPP activity supported the NH2-truncation of CXCL10. Finally, we demonstrated an increased frequency of CXCR3(+) cells in the peripheral blood, and low numbers of CXCR3(+) cells within the lobular regions of the liver. These findings generalize the observation of chemokine antagonism as a mechanism of immune modulation in chronic HCV patients and may help guide the use of new therapeutic immune modulators.
Subject(s)
Chemokine CXCL10/blood , Dipeptidyl Peptidase 4/blood , Hepatitis C, Chronic/immunology , Adolescent , Adult , Chemokine CXCL10/antagonists & inhibitors , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Egypt , Female , Hepacivirus/immunology , Hepatitis C, Chronic/virology , Humans , Inflammation/immunology , Liver/cytology , Liver/immunology , Liver/metabolism , Lymphocyte Subsets/immunology , Lymphocyte Subsets/metabolism , Male , Middle Aged , Receptors, CXCR3/metabolism , Young AdultABSTRACT
Late infantile neuronal ceroid lipofuscinosis (LINCL) is caused by mutations in the gene encoding tripeptidyl-peptidase 1 (TPP1). LINCL patients accumulate lysosomal storage materials in the CNS accompanied by neurodegeneration, blindness, and functional decline. Dachshunds homozygous for a null mutation in the TPP1 gene recapitulate many symptoms of the human disease. The objectives of this study were to determine whether intrathecal (IT) TPP1 treatment attenuates storage accumulation and functional decline in TPP1-/- Dachshunds and to characterize the CNS distribution of TPP1 activity. TPP1 was administered to one TPP1-/- and one homozygous wild-type (WT) dog. An additional TPP1-/- and WT dog received vehicle. Four IT administrations of 32 mg TPP1 formulated in 2.3 mL of artificial cerebrospinal fluid (aCSF) or vehicle were administered monthly via the cerebellomedullary cistern from four to seven months of age. Functional decline was assessed by physical and neurological examinations, electrophysiology, and T-maze performance. Neural tissues were collected 48 h after the fourth administration and analyzed for TPP1 activity and autofluorescent storage material. TPP1 was distributed at greater than WT levels in many areas of the CNS of the TPP1-/- dog administered TPP1. The amount of autofluorescent storage was decreased in this dog relative to the vehicle-treated affected control. No improvement in overall function was observed in this dog compared to the vehicle-treated TPP1-/- littermate control. These results demonstrate for the first time in a large animal model of LINCL widespread delivery of biochemically active TPP1 to the brain after IT administration along with a decrease in lysosomal storage material. Further studies with this model will be necessary to optimize the dosing route and regimen to attenuate functional decline.
Subject(s)
Aminopeptidases/pharmacology , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/pharmacology , Lysosomes/metabolism , Neuronal Ceroid-Lipofuscinoses/drug therapy , Neuronal Ceroid-Lipofuscinoses/metabolism , Serine Proteases/pharmacology , Aminopeptidases/administration & dosage , Aminopeptidases/blood , Aminopeptidases/genetics , Aminopeptidases/therapeutic use , Animals , CHO Cells , Central Nervous System/metabolism , Chromatography, Gel , Chromatography, Ion Exchange , Cricetinae , Cricetulus , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/administration & dosage , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/genetics , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/therapeutic use , Dogs , Electrophysiology , Fluorescence , Gene Knockout Techniques , Humans , Immunoassay , Immunoglobulin E/blood , Injections, Spinal , Magnetic Resonance Imaging , Maze Learning/drug effects , Recombinant Proteins/pharmacology , Serine Proteases/administration & dosage , Serine Proteases/blood , Serine Proteases/genetics , Serine Proteases/therapeutic use , Tripeptidyl-Peptidase 1Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Glucagon-Like Peptide 1/analogs & derivatives , Glucagon-Like Peptide 1/pharmacology , Incretins/pharmacology , Blood Glucose/drug effects , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/blood , Dipeptidyl-Peptidase IV Inhibitors/pharmacology , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/antagonists & inhibitors , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood , Humans , LiraglutideABSTRACT
Linagliptin (BI 1356) is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor in clinical development for the treatment of type 2 diabetes. It exhibits non-linear pharmacokinetics and shows concentration-dependent plasma protein binding to its target, DPP-4. The aim of this study was to investigate the impact of saturable binding of linagliptin to plasma and tissue DPP-4 by comparing the pharmacokinetics of linagliptin in wildtype and DPP-4 deficient Fischer rats using non-compartmental and model-based data analysis. The non-compartmental analysis revealed a significantly reduced AUC in DPP-4 deficient rats compared with wildtype rats when single intravenous doses Subject(s)
Dipeptidyl Peptidase 4/blood
, Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/blood
, Purines/pharmacology
, Quinazolines/pharmacology
, Animals
, Binding Sites
, Diabetes Mellitus, Type 2/drug therapy
, Diabetes Mellitus, Type 2/enzymology
, Diabetes Mellitus, Type 2/metabolism
, Dipeptidyl-Peptidase IV Inhibitors/pharmacology
, Linagliptin
, Rats
, Rats, Inbred F344