Assessing carnosinase 1 activity for diagnosing congenital disorders of glycosylation.

Diagnosing Congenital Disorders of Glycosylation (CDG) is challenging due to clinical heterogeneity and the limited sensitivity of the classic serum transferrin isoelectric focusing (IEF) or capillary zone electrophoresis test. This study investigates the potential of using the glycoprotein carnosinase 1 (CN1) activity as a diagnostic marker for CDG patients. CN1 activity was measured photometrically in serum from 81 genetically confirmed CDG patients and healthy individuals. While the IEF transferrin method detected 77 patients, four remained undetected. In healthy individuals, serum CN1 activity ranged from 0.1 to 6.4 µmol/ml/h depending on age, with mean CN1 activities up to four-fold higher than in CDG patients. CDG patients´ CN1 activities never exceeded 2,04 µmol/ml/h. Using the 25th percentile to differentiate between groups, the test performance varied by age. For children over 10 years old, the sensitivity and specificity were 96 % and 83 %, respectively. For those under 10, sensitivity and specificity dropped to 71 % and to 64 %. However, CN1 activity successfully identified three of four patients with normal IEF patterns. Although mean CN1 activity in CDG patients is significantly lower than in healthy controls, the test's reliability for classic CDG diagnosis is limited, as the diagnosis is usually made at a young age. Nevertheless, it is a simple, cost-effective assay that can complement classic tests, especially in settings with limited access to complex methods or for patients with normal transferrin patterns but suspicious for CDG.

Prolidase activity in women with polycystic ovarian syndrome undergoing assisted conception.

Background: Prolidase is a manganese (Mn)-dependent cytosolic exopeptidase that degrades imidodipeptides with C-terminal proline or hydroxyproline. Prolidase recycling from imidodipeptides plays a critical role in collagen resynthesis and extracellular matrix (ECM) remodelling. Following an increase in gonadotropins, ovarian and follicular collagen undergo substantial degradation. Abnormal ovarian ECM composition is associated with polycystic ovary syndrome (PCOS). This study aimed to examine prolidase activity in the serum and follicular fluid (FF) of women undergoing in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) treatment, comparing those with PCOS to those with normal ovarian function.Methods: This prospective study enrolled 50 participants, of whom 44 were included. PCOS diagnosis followed the Rotterdam consensus criteria, with 20 patients constituting the study group. The control group comprised 24 individuals with mild-to-moderate male infertility. Prolidase enzyme activity in serum and FF was measured using the Chinard reagent via spectrophotometric analysis and compared between the groups.Results: Serum and FF prolidase levels were significantly lower in patients with PCOS (p < 0.05). A direct correlation was observed between serum and FF prolidase levels (p < 0.05). Although blastocyst quality scoring (BQS) significantly decreased in PCOS patients, no statistical difference was observed in the clinical pregnancy rate between the groups (p < 0.05) (p > 0.05). A negative correlation existed between serum prolidase levels and total antral follicle (AF) count (p < 0.05). Conversely, both serum and FF prolidase levels positively correlated with BQS (r = 0.574)(p < 0.05) (r = 0.650)(p < 0.05).Conclusions: Patients with PCOS showed lower serum and FF prolidase levels, indicating abnormal degradation of ovarian and follicular collagen, potentially causing anovulation.

Polycystic ovary syndrome (PCOS), the most prevalent endocrinopathy among reproductive-aged women, affects approximately 3­15% of this demographic. Long-term disorders such as cardiovascular disease, type 2 diabetes mellitus, obesity, and infertility are commonly associated with PCOS, with approximately 70% of affected women experiencing infertility. Although the aetiology of PCOS remains unclear, complex multigenic disorders and environmental factors such as abnormal ovarian extracellular matrix composition, disruption of the inflammatory pathway, and lifestyle factors have been found to be related.This study addresses the aetiology of PCOS, focusing on the close association between abnormal ovarian extracellular matrix composition and the syndrome, as seen in previous reports. Prolidase is a manganese-dependent cytosolic exopeptidase that degrades imidodipeptides using the C-terminal proline or hydroxyproline. Proline recycling from imidodipeptides by prolidase plays a critical role in the resynthesis of collagen and remodelling of the extracellular matrix. Our aim was to evaluate prolidase activity in the serum and follicular fluid of women diagnosed with PCOS. Our findings revealed a direct correlation between serum and follicular fluid prolidase levels, both of which were diminished in women with PCOS. Furthermore, a negative correlation was observed between serum prolidase levels and total antral follicle count indicating a potential link between prolidase activity and ovarian follicle development. In contrast, both serum and follicular fluid prolidase levels were positively correlated with blastocyst quality. In conclusion, PCOS patients showed lower serum and follicular fluid prolidase levels, indicating abnormal degradation of ovarian and follicular collagen, and potentially causing anovulation. Future studies measuring manganese levels in larger numbers of participants are required.

Prolidase activity in aqueous and serum samples of cataract cases with Pseudoexfoliation syndrome.

Pseudoexfoliation syndrome (PEX) represents an age-related systemic disease that is characterized by the accumulation of extracellular matrix material in ocular tissues and visceral organs. Abnormal matrix remodeling is thought to be one of the important factors in the etiopathogenesis of the disease. Prolidase represents an enzyme, which takes a significant part in collagen biosynthesis and remodeling of the extracellular matrix. The purpose of the current research was to assess the prolidase enzyme activity in the aqueous and serum samples of subjects with PEX. The study population consisted of 66 subjects, involving 33 subjects with age-related cataract among patients with PEX and 33 subjects with age-related cataract without PEX. The prolidase activity measurement was performed using the modified Chinard's method. Significantly increased aqueous prolidase activity was detected in the group with PEX (p < 0.01). Despite about a three times higher increase in the serum prolidase activity of the group with PEX in comparison with the control group, the two groups did not differ statistically significantly (p > 0.05). The high prolidase enzyme activity in the aqueous samples of subjects with PEX suggests that the collagen cycle and the remodeling of the extracellular matrix are accelerated. These results can be a guide for understanding the formation mechanisms of PEX.

Correlation between serum carnosinase concentration and renal damage in diabetic nephropathy patients.

Diabetic nephropathy (DN) is one of the major complications of diabetes and contributes significantly towards end-stage renal disease. Previous studies have identified the gene encoding carnosinase (CN-1) as a predisposing factor for DN. Despite this fact, the relationship of the level of serum CN-1 and the progression of DN remains uninvestigated. Thus, the proposed study focused on clarifying the relationship among serum CN-1, indicators of renal function and tissue injury, and the progression of DN. A total of 14 patients with minimal changes disease (MCD) and 37 patients with DN were enrolled in the study. Additionally, 20 healthy volunteers were recruited as control. Further, DN patients were classified according to urinary albumin excretion rate into two groups: DN with microalbuminuria (n = 11) and DN with macroalbuminuria (n = 26). Clinical indicators including urinary protein components, serum carnosine concentration, serum CN-1 concentration and activity, and renal biopsy tissue injury indexes were included for analyzation. The serum CN-1 concentration and activity were observed to be the highest, but the serum carnosine concentration was the lowest in DN macroalbuminuria group. Moreover, within DN group, the concentration of serum CN-1 was positively correlated with uric acid (UA, r = 0.376, p = 0.026) and serum creatinine (SCr, r = 0.399, p = 0.018) and negatively correlated with serum albumin (Alb, r = - 0.348, p = 0.041) and estimated glomerular filtration rate (eGRF, r = - 0.432, p = 0.010). Furthermore, the concentration of serum CN-1 was discovered to be positively correlated with indicators including 24-h urinary protein-creatinine ratio (24 h-U-PRO/CRE, r = 0.528, p = 0.001), urinary albumin-to-creatinine ratio (Alb/CRE, r = 0.671, p = 0.000), urinary transferrin (TRF, r = 0.658, p = 0.000), retinol-binding protein (RBP, r = 0.523, p = 0.001), N-acetyl-glycosaminidase (NAG, r = 0.381, p = 0.024), immunoglobulin G (IgG, r = 0.522, p = 0.001), cystatin C (Cys-C, r = 0.539, p = 0.001), beta-2-microglobulin (ß2-MG, r = 0.437, p = 0.009), and alpha-1-macroglobulin (α1-MG, r = 0.480, p = 0.004). Besides, in DN with macroalbuminuria group, serum CN-1 also showed a positive correlation with indicators of fibrosis, oxidative stress, and renal tubular injury. Taken together, our data suggested that the level of CN-1 was increased as clinical DN progressed. Thus, the level of serum CN-1 might be an important character during the occurrence and progression of DN. Our study will contribute significantly to future studies focused on dissecting the underlying mechanism of DN.

Plasma oxidative-stress parameters and prolidase activity in patients with various causes of abdominal pain.

PURPOSE: We aimed to investigate the predictive power of plasma prolidase activity and oxidative-stress parameters for distinguishing in patients with various causes of non-traumatic abdominal pain who presented to the emergency department. METHODS: This study enrolled 100 consecutive adult patients and 100 age- and sex-matched healthy controls. The patients were divided into surgically treated patients (STP); medically treated patients (MTP) and nonspecific abdominal pain (NSAP) patients. As predictors of early oxidative changes, the plasma prolidase activity, total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) were assessed using a novel automated method. RESULTS: No significant difference was observed between the patients and the controls with respect to age or sex (p = 0.837 and 0.188, respectively). The plasma TOS, OSI value, and prolidase activity were significantly higher in the patients with abdominal pain than in the controls (p < 0.001, p = 0.001, and p < 0.001, respectively); however, there was no significant difference in the TAS (p = 0.211). The mean plasma TOS, OSI value, and prolidase activity differed significantly among the three groups (p < 0.001, p = 0.001, and p < 0.001, respectively). The STP had the highest TOS and prolidase activity. However, there was no significant difference in the mean plasma TAS in either group of patients (p = 0.419). CONCLUSION: The plasma prolidase activity and TOS level, as biomarkers of oxidative stress, enable discrimination of patients with NSAP from those with surgical abdominal pain that requires emergent surgical treatment.

Is there a correlation between obstructive sleep-apnea syndrome severity and prolidase activity as an oxidative stress marker?

OBJECTIVE: Obstructive sleep apnea syndrome (OSAS) is a highly prevalent breathing disorder in sleep. The aim of this study was to evaluate the relationship between OSAS and prolidase activity, the oxidative stress index (OSI), total antioxidative capacity (TAC), total oxidative capacity (TOC) and the carotid intima media thickness (CIMT). METHOD: : After night polysomnography, 74 people were diagnosed with OSAS and simple snoring. Plasma prolidase activities, TAC and TOC were measured in blood samples taken in the morning after the sleep study. The patients' bilateral common carotid arteries were scanned. RESULTS: In total, 56 patients were in OSAS group [13 subjects 23.2% mild, 19 subjects 33.9% moderate, 24 subjects 42.8% severe] and 18 in simple snoring control group. The mean Prolidase, TOC, TAC and OSI levels were 744.7 ± 156.8, 59.2 ± 19.2, 2.12 ± 0.41, 3.12 ± 1.03, in the mild OSAS group, 761.6 ± 114.4, 57.9 ± 18.3, 2.03 ± 0.37, 3.15 ± 0.8, in the moderate OSAS group, 754.08 ± 133.9, 51.15 ± 12.1, 1.97 ± 0.27, 2.8 ± 0.82, in the severe OSAS group, and 711.9 ± 139, 52.3 ± 15.1, 1.83 ± 0.32, 3.06 ± 0.92 in the control group, respectively. Mean CIMT measurements were 0.71(±0,13) in the OSAS group and 0.76(±0.07) in the control group. CONCLUSION: There was no difference between the control and OSAS groups in terms of the parameters studied. Further studies should be undertaken in order to clarify the relation.

Identification and characterisation of carnostatine (SAN9812), a potent and selective carnosinase (CN1) inhibitor with in vivo activity.

Carnosinase 1 (CN1) has been postulated to be a susceptibility factor for developing diabetic nephropathy (DN). Although its major substrate, carnosine, is beneficial in rodent models of DN, translation of these findings to humans has been hampered by high CN1 activity in human serum resulting in rapid degradation of carnosine. To overcome this hurdle, we screened a protease-directed small-molecule library for inhibitors of human recombinant CN1. We identified SAN9812 as a potent and highly selective inhibitor of CN1 activity with a Ki of 11 nM. It also inhibited CN1 activity in human serum and serum of transgenic mice-overexpressing human CN1. Subcutaneous administration of 30 mg/kg SAN9812 led to a sustained reduction in circulating CN1 activity in human CN1 transgenic (TG) mice. Simultaneous administration of carnosine and SAN9812 increased carnosine levels in plasma and kidney by up to 100-fold compared to treatment-naïve CN1-overexpressing mice. To our knowledge, this is the first study reporting on a potent and selective CN1 inhibitor with in vivo activity. SAN9812, also called carnostatine, may be used to increase renal carnosine concentration as a potential therapeutic modality for renal diseases linked to glycoxidative conditions.

Evaluation of Serum Paraoxonase, Arylesterase, Prolidase Activities and Oxidative Stress in Patients with Alopecia Areata.

BACKGROUND: Alopecia areata (AA) is a disease characterized by the hair loss sharply limited in any part of the body, especially on the scalp, in circular or oval areas. The purpose of this study is to search the serum paraoxonase 1 (PON1), arylesterase and oxidative status with serum prolidase activities in people with AA. METHODS: The study included 60 AA and 50 healthy control subjects. In both groups, serum PON1, prolidase, arylesterase activities, total oxidative status (TOS) and total antioxidant capacity (TAS) levels and oxidative stress index (OSI) were calculated. RESULTS: TOS, OSI levels and prolidase activity in patients with AA were found to be significantly higher compared to the control group (p = 0.02, p = 0.004, p < 0.001, respectively), whereas PON1 and arylesterase activities were significantly lower (p < 0.001, p = 0.005, respectively). There was no difference in serum TAS levels between the two groups. CONCLUSION: This comprehensive work shows that the role of oxidative stress is very important in the pathogenesis of AA. In this study, we believe that we clarified the pathogenesis of oxidative stress for AA patients by investigating the TAS, TOS, OSI levels, PON1, arylesterase and prolidase enzyme activity parameters.

Serum prolidase level in patients with brucellosis and its possible relationship with pathogenesis of the disease: a prospective observational study

Background/aim: Changes in collagen metabolism and fibroblastic activity may play a role in the pathogenesis of brucellosis. The prolidase enzyme plays an important role in collagen synthesis. We aimed to investigate the association of prolidase levels with brucellosis. Materials and methods: Serum prolidase levels in 20 patients newly diagnosed with brucellosis were compared with levels in 30 healthy control subjects. Patients with brucellosis were reassessed 3 months later for prolidase, other laboratory measurements, and response to treatment. Results: The levels of serum prolidase were significantly higher in brucellosis patients compared with those of healthy controls. Prolidase, sedimentation, and C-reactive protein levels were significantly lower after antibrucellosistreatment than before treatment. Conclusion: The current study is the first to demonstrate significantly increased serum prolidase levels in patients with brucellosis compared with healthy controls. Prolidase levels also significantly decreased with antibrucellosis treatment. This finding provides a new experimental basis to understand the pathogenesis of brucellosis in relation to collagen metabolism. The increase in serum prolidase levels might be related to several factors such as tissue destruction, increased fibroblastic activity, and granuloma formation, all of which are involved in the natural history of brucellosis.

Evaluation of serum prolidase activity and oxidative stress markers in men with BPH and prostate cancer.

BACKGROUND: Prostate cancer (PCa) and benign prostatic hyperplasia (BPH) are diseases of elderly men and are related to increased oxidative stress (OS). Although prolidase has a role in collagen metabolism, it is also used to evaluate OS in many diseases. However, there is a lack of data about serum prolidase activity (SPA) in prostate cancer. The aim of this study was to evaluate and compare SPA levels in males with BPH and PCa. METHODS: Evaluation was made of a total of 81 men who underwent transrectal ultrasound guided prostate biopsy for a definitive diagnosis due to high PSA levels. Patients were separated into 2 groups as BPH and PCa patients. Pre-biopsy malondialdehyde (MDA), superoxide dismutase (SOD), PSA levels and serum prolidase activities (SPA) were compared between the groups and the correlations of SPA with the other parameters were also investigated in both groups. RESULTS: BPH was diagnosed in 51 patients and PCa in 30. The mean age of patients was similar in both groups as 63.25 ± 5.81 years in the BPH group 65.30 ± 7.35 years in the PCa group(p:0.081). The median MDA and SOD levels were insignificantly increased in the PCa patients. SPA values were similar in BPH and PCa patients. SPA did not correlate with age, PSA, MDA or SOD levels in either group. CONCLUSIONS: Our study results revealed that serum prolidase activity is similar in BPH and PCa cases and is not correlated with MDA, SOD or PSA levels.

Evaluation of prolidase activity and oxidative stress in patients with oral lichen planus and oral lichenoid contact reactions.

OBJECTIVE: The aim of this study was to evaluate prolidase activity and oxidative stress in patients with oral lichen planus (OLP) and oral lichenoid contact reactions (OLCR) using serum and salivary samples and to compare these biomarkers with each other as well as with a group of healthy subjects in order to be able to opine their role in the estimation of OLP and OLCR. PATIENTS AND METHODS: Eighteen recently diagnosed patients with OLP, 32 patients with OLCR and 18 healthy controls with matched periodontal status were recruited to the study. Prolidase activity, lipid peroxidation product malondialdehyde (MDA), sialic acid (SA), and advanced oxidation protein products (AOPPs) levels in both serum and saliva were determined. Additionally, salivary flow rate and its buffering capacity were estimated. Statistical analyses were performed using the chi-square test, t-test, Mann-Whitney U-test, and Spearman's rho correlation coefficient. RESULTS: No statistically significant differences were observed between the study groups and the control group regarding to the basic characteristics and the periodontal status (P > 0.05). There were no statistically significant differences between OLP and OLCR groups regarding to the distribution of lesions' type, severity, and location (P > 0.05). No significant differences were found between the two study groups with regard to Prolidase activity, MDA, SA, and AOPPs (P ˃ 0.05), whereas statistically significant differences were found between the two study groups and the control group with regard to all evaluated parameters except of serum prolidase (P ˂ 0.01). Moderate correlation was found between salivary MDA and the OLP/OLCR lesion severity, whereas a weak correlation was observed between serum SA and the OLP/OLCR lesion severity (P ˂ 0.05). CONCLUSIONS: The findings of this study suggest an increased prolidase activity and oxidative stress and imbalance in the antioxidant defense system in biological fluids of patients with OLP and OLCR when compared with the healthy subjects. Both OLP and OLCR patients revealed almost similar prolidase activity and oxidative stress levels although these two conditions have different etiopathogenesis.

Serum prolidase level in ankylosing spondylitis: low serum levels as a new potential gold standard biomarker for disease activity.

Ankylosing spondylitis (AS) is a chronic inflammatory disorder that mainly affects the sacroiliac joints and axial skeleton. The aim of this study was to assess serum prolidase level (SPL) and its association with disease activity in patients with AS. This prospective study included 75 AS patients. Thirty age- and gender-matched healthy controls were enrolled. AS patients were considered as active if BASDAI score was ≥4 or inactive if BASDAI score was <4. There were 34 AS patients in the active group and 41 AS patients in the inactive group. Anti-TNF-monoclonal antibody treatment was started in patients in the active group. These active patients were reassessed 6 months later. BASDAI, ASDAS, visual analogue scale, short-form-general health survey questionnaire, C-reactive protein, erythrocyte sedimentation rate and SPL were measured in all AS patients before and after treatment. The SPL was significantly lower in inactive AS patients than in control group, and also, SPL was significantly lower in active AS patients than in inactive patients. All activity parameters were successful in separating active and inactive AS patients. However, the only parameter that could distinguish active patients from inactive patients was prolidase. The optimum cutoff point of SPL to identify patients with active AS was 23.13 ng/mL with sensitivity, specificity, positive predictive value and negative predictive value of 100 %. Serum prolidase level was successful in measuring disease activity and had as high sensitivity and specificity as BASDAI and was superior to other activity parameters.

The Value of Serum Prolidase Activity in Progression of Microalbuminuria in Patients With Type 2 Diabetes Mellitus.

BACKGROUND: Prolidase is a cytosolic exopeptidase that plays a pivotal role in collagen turnover. Diabetic nephropathy (DN) is associated with structural changes in glomerular basement membrane accompanied with increased amounts of collagen. Prolidase is known to be abundant in kidney and collagen accumulation is increased in DN, so we aimed to determine the value of serum prolidase activity (SPA) in predicting the progression of nephropathy in type 2 diabetes mellitus (DM). METHODS: Thirty type 2 DM patients having microalbuminuria (microalbuminuric group), 30 type 2 DM patients without albuminuria (normoalbuminuric group), and 28 healthy controls (control group) were enrolled. Study groups had similar age, sex distribution, and body mass index (BMI). RESULTS: Metabolic parameters, SPA and urinary microalbumin were determined. SPA was significantly higher in microalbuminuric group when compared with normoalbuminuric and control groups (P = 0.05 and P < 0.001, respectively). Triglyceride levels were significantly higher and high density lipoprotein cholesterol (HDL-C) levels were significantly lower in microalbuminuric group compared to control group (Both P < 0.05). SPA showed a negative correlation with HDL-C level and a positive correlation with urinary albumin excretion (r = -0.219, P < 0.05 and r = 0.39, P < 0.001 respectively). In regression analysis, albumin excretion was the sole parameter influencing SPA. CONCLUSION: SPA appears to be higher in type 2 DM patients having microalbuminuria compared to patients without microalbuminuria and healthy controls. The pathophysiological role and the significance of SPA in predicting DN need to be further evaluated.

Serum prolidase activity, oxidative stress, and antioxidant enzyme levels in patients with renal cell carcinoma.

OBJECTIVES: Prolidase is a member of the matrix metalloproteinase family. It plays a vital role in collagen turnover, matrix remodeling, and cell growth. Reactive oxygen species (ROS) have been implicated in the pathogenesis of various diseases, including cancers. Oxidative stress can cause tumor angiogenesis and may be carcinogenic. However, the relationship between antioxidant capacity and various cancers has been researched in several clinical trials. In our study, we aimed to identify serum prolidase activity, oxidative stress, and antioxidant enzyme levels in patients with renal tumors and to evaluate their relationships with each other. MATERIALS AND METHODS: A total of 37 male patients with renal cell cancer and with a mean age of 56.28 ± 3.1 were included in the study. The control group comprising 36 male patients (mean age 56.31 ± 2.9) was randomly selected among the volunteers. Serum samples for measurement of superoxide dismutase (SOD), glutathione peroxidase (GSHPx), glutathione-S-transferase (GST), malondialdehyde (MDA), glutathione (GSH), and prolidase levels were kept at -20°C until they were used. RESULTS: Serum prolidase activity and MDA levels were significantly higher in renal cancer patients than in controls (all, p < 0.05), while SOD, GSHPx, and GST levels were significantly lower (p < 0.05). CONCLUSION: Our results indicate that increased prolidase seems to be related to increased oxidative stress along with decreased antioxidant levels in renal cancer.

Prolidase.

Prolidase (EC.3.4.13.9) or proline dipeptidase, is one of the unique enzyme capable of degrading dipeptides, in which a proline or hydroxyproline residue is located at the C-terminal position. Prolidase has a unique function in all cell types; therefore, the mechanisms and parameters involved in prolidase activity regulation are of special interest. Could prolidase be a good biomarker in different physiologic and pathologic conditions? This is an important question. There is no consensus on the answer to this question. It is of great importance during collagen turnover, inflammation, tissue fibrosis and skeletal abnormalities.Prolidase itself without other biochemical markers may not provide information to clinicians about disease activity. So, I think it should be evaluated together with other serum biochemical markers.This review will serve to discuss many in vivo functions of prolidase, as well as level prolidase activity in diagnosis and monitoring of treatment in the various diseases (Ref. 50).

The value of prolidase enzyme in rats with experimentally induced mild and severe pancreatitis.

INTRODUCTION: Acute pancreatitis is basically considered as activation of inactive proenzymes in the pancreas and digestion of the gland itself. This study was performed to determine if prolidase enzyme, which plays a role in collagen metabolism, could be used as a parameter to assess the severity of pancreatitis in experimentally induced mild and severe pancreatitis. MATERIAL AND METHOD: To create experimentally induced acute pancreatitis 0.1 ml of normal saline solution (NSS) was given five times with an interval of one hour to rats in the first group; 50 µg/kg of cerulein five times with an interval of one hour in the second group; 80 µg/kg of cerulein five times with an interval of one hour in the third group, in the form of intraperitoneal injection. RESULTS: When the serum prolidase values at beginning, 1st, 5th and 24th hours in group II and III were compared among themselves, there was a statistically significant increase(p < 0.05). The evaluation between groups revealed a statistically significant increase in the value of serum prolidase in group II and group III compared with the control group (p < 0.05). In comparisons performed with tissue values, a statistically significant increase determined in the value of serum prolidase in group II and group III compared with the control group was observed (p < 0.05). CONCLUSION: The findings obtained in our study showed that prolidase activity increases directly proportionaly with the severity of pancreatitis. This allows us to postulate that prolidase enzyme activities provide guidance about the metabolism of collagen in patients with acute pancreatitis, serious damage occurring in collagen protein and metabolic control is further distorted depending on the duration and intensity of damage but to be able to speak more precisely, there is a need for further, more detailed and extensive researchs (Tab. 8, Fig. 2, Ref. 30).

Aerobic and resistance training do not influence plasma carnosinase content or activity in type 2 diabetes.

A particular allele of the carnosinase gene (CNDP1) is associated with reduced plasma carnosinase activity and reduced risk for nephropathy in diabetic patients. On the one hand, animal and human data suggest that hyperglycemia increases plasma carnosinase activity. On the other hand, we recently reported lower carnosinase activity levels in elite athletes involved in high-intensity exercise compared with untrained controls. Therefore, this study investigates whether exercise training and the consequent reduction in hyperglycemia can suppress carnosinase activity and content in adults with type 2 diabetes. Plasma samples were taken from 243 males and females with type 2 diabetes (mean age = 54.3 yr, SD = 7.1) without major microvascular complications before and after a 6-mo exercise training program [4 groups: sedentary control (n = 61), aerobic exercise (n = 59), resistance exercise (n = 63), and combined exercise training (n = 60)]. Plasma carnosinase content and activity, hemoglobin (Hb) A1c, lipid profile, and blood pressure were measured. A 6-mo exercise training intervention, irrespective of training modality, did not decrease plasma carnosinase content or activity in type 2 diabetic patients. Plasma carnosinase content and activity showed a high interindividual but very low intraindividual variability over the 6-mo period. Age and sex, but not Hb A1c, were significantly related to the activity or content of this enzyme. It can be concluded that the beneficial effects of exercise training on the incidence of diabetic complications are probably not related to a lowering effect on plasma carnosinase content or activity.

N-acetylated α-linked acidic dipeptidase is identified as an antigen of Histoplasma capsulatum.

Histoplasmosis, one of the most important mycoses, needs to be diagnosed rapidly and accurately. The main method used to diagnose histoplasmosis is serological detection of antibodies to the Histoplasma capsulatum H and M antigens. Several other protein antigens have been reported in H. capsulatum; however, they have not been used for diagnosis. In this study, we explored novel antigens that were detected during H. capsulatum infection. We obtained a protein mixture from H. capsulatum yeast cells after vigorous mixing in a 0.1% Triton X-100 solution. From the resultant pool, we detected nine spots that reacted with sera from patients with histoplasmosis and identified eight seroactive proteins with mass spectrometry. The seroactive proteins were purified, and their antigenicities were tested with an enzyme-linked immunosorbent assay (ELISA). ELISA revealed that the titer of the patients' sera to N-acetylated α-linked acidic dipeptidase was significantly higher than those of healthy volunteers (P < 0.01). These data indicate that N-acetylated α-linked acidic dipeptidase of H. capsulatum is recognized as a major antigen during histoplasmosis.

Serum prolidase levels in Graves' disease without ophthalmopathy and its association with oxidative status.

OBJECTIVE: The aim of this study was to evaluate serum prolidase levels and its association with oxidative stress in autoimmune thyroid disease (AITD). MATERIALS AND METHODS: 25 with Hashimoto thyroiditis (HT) and 25 patients Graves' disease (GD), and 27 healthy controls were enrolled in the study. The patients with signs of Graves' ophthalmopathy were excluded from the study. Serum samples were obtained in euthyroid period at the third month of treatment. Serum prolidase, total antioxidant status (TAS), total oxidative stress (TOS), and total free sulfhydryl (-SH) levels were measured. RESULTS: Serum prolidase levels were significantly higher in the patients with GD compared to the HT and the healthy control group. Oxidative stress index (OSI) and TOS levels of the patients with both GD and HT were significantly higher compared to those of the control group (p < 0.001, for each), while -SH levels were significantly lower (p < 0.001, for each). There was no significant difference between the patients with HT and healthy control group in terms of prolidase levels (p = 0.580). Prolidase levels were positively correlated with TOS and OSI and negatively correlated with -SH (r = 0.565, p = 0.003; r = 0.604, p = 0.001; r = -0.532, p = 0.006). CONCLUSION: Serum prolidase activity is increased in GD patients without signs of ophthalmopathy, and showed a positive correlation with oxidative stress parameters.

Evaluation of the utility of serum prolidase as a marker for liver fibrosis.

BACKGROUND: Liver dysfunction is common and often unrecognized. Liver biopsy is the gold standard in the assessment of liver fibrosis, but has disadvantages. We assessed the diagnostic accuracy of serum prolidase enzyme activity (SPA) in predicting the presence and degree of liver fibrosis, as compared with liver biopsy. Further, we evaluated the effect of hemolysis on measured SPA levels. METHODS: We undertook a prospective case control study. Thirty eight outpatients without apparent liver illness and 20 patients with liver pathology scheduled to undergo liver biopsy had their SPA levels measured. RESULTS: Patients undergoing liver biopsy had higher SPA levels (361 (268) IU/l [median (interquartile range)]) compared with controls (169 (160) (P < 0.001)). A SPA cutoff value of 200 IU/l yielded a sensitivity of 89%, specificity of 59%, an odds ratio of 11.5, negative predictive value of 92%, and a positive predictive value of 50%. Hemolysis causes an apparent increase in SPA levels. CONCLUSION: Higher SPA levels in patients undergoing liver biopsies compared with controls may reflect the presence of liver fibrosis. SPA levels could not be used to stage the degree of fibrosis. SPA measurement may be useful in the diagnostic workup of suspected liver disease.