Establishment of the first stool bank in an Eastern European country and the first series of successful fecal microbiota transplantations in Bulgaria.

OBJECTIVE: For safe implementation and broader application of fecal microbiota transplantation (FMT), quality controlled stool banking is a must. Establishing a stool bank is a complex, time-consuming, and expensive process, making it a real challenge in an Eastern European country. We aimed to establish the first stool bank in Eastern Europe - in Bulgaria. SUBJECTS AND METHODS: A multidisciplinary team of gastroenterologists, microbiologists, infectionists, and geneticists was set up. We used a questionnaire based on the First European FMT Consensus in order to recruit possible stool donors. Laboratory blood and stool tests were performed on all potential donors. RESULTS: Between October 2018 and April 2019, 112 donor volunteers completed a questionnaire; 70 (62.5%) were excluded, mainly because of age above 50, an unhealthy BMI, and risk behavior. Fourty-two (37.5%) donor candidates were invited for laboratory testing of blood and feces, of which 12 (28.6%) passed this screening. Of 12 donors, 4 (33%) failed at the following screening test, which is performed every 3-6 months. Finally, 8 (7.14%) active donors were enrolled. Ten successful FMTs were performed on patients with recurrent Clostridium difficile infection. CONCLUSIONS: Even though we found many healthy volunteers, only a low percentage (7.14%) of them were suitable to become feces donors. Establishing a stool bank in an Eastern European country is essential for making FMT safe and more popular as a treatment method, finding further implementation and regulation of FMT and supporting physicians offering this treatment to their patients.

Evaluation of the clinical value of the newly identified urine biomarker HIST1H4K for diagnosis and prognosis of prostate cancer in Bulgarian patients.

PURPOSE: Searching for diagnostic and prognostic biomarkers for prostate cancer (PC) is main public health priority. DNA methylation in body fluids is a stable, easily detectable and promising PC biomarker. The major advantages of urine-based assays are their noninvasive nature and the ability to monitor PC with heterogeneous foci. The aim of this study was to determine the diagnostic value of the recently identified candidate PC biomarker HIST1H4K. METHODS: We investigated DNA methylation of HIST1H4K in urine samples from 57 PC patients, 29 controls with benign prostatic hyperplasia (BPH) and 50 young asymptomatic men (YAM) by MethyLight real-time PCR. RESULTS: The frequency of HIST1H4K promoter hypermethylation significantly discriminated PC patients from YAM (AUC =0.763; 95% CI 0.672-0.839; p<0.0001), but did not show any statistical difference between PC patients and BPH controls (AUC=0.513, 95% CI 0.402-0.622; p=0.8255). HIST1H4K could not outperform the prostatic specific antigen (PSA) in our sample (AUC=0.785; 95% CI 0.679-0.870; p<0.0001). Methylation of HIST1H4K showed significant correlation with aging (r=0.5418; p<0.0001), but with no other clinicopathological characteristics. CONCLUSION: The results suggest that the promoter hypermethylation of HIST1H4K is rather due to aging than related to prostate carcinogenesis. To elucidate this observation analysis of larger samples is needed.

Microsatellite instability and promoter hypermethylation of MLH1 and MSH2 in patients with sporadic colorectal cancer.

PURPOSE: Inactivation of the genes involved in DNA mismatch repair (MMR) is associated with microsatellite instability (MSI) and loss of heterozygosity (LOH). The aim of the current study was to assess the presence of MSI and promoter hypermethylation of MLH1 and MSH2 in Bulgarian PATIENTS WITH SPORADIC COLORECTAL CANCER (CRC) AND TO ANALYZE THEIR POSSIBLE EFFECT ON THE DEVELOPMENT, PROGRESSION AND PROGNOSIS OF THE DISEASE. METHODS: We examined MSI in 126 patients with sporadic CRC and the methylation status of the MLH1 and MSH2 promoter regions in the cases with MSI/LOH by using a panel of 5 microsatellite markers (BAT26, D5S346, D18S35, D2S123 and FGA) and methyl-specific PCR (MSP) of bisulfite converted DNA. RESULTS: MSI/LOH was found in 36 (28.6%) patients. Among them, 30 were analyzed for promoter hypermethylation of MLH1 and we detected hypermethylation in 15 (50%) of them, whereas promoter hypermethylation of MSH2 was observed only in one case. The presence of MSI/LOH was associated with younger age (p=0.002), more advanced stage (III/IV stage) (p=0.029), lower degree of differentiation (p=0.001), and right-sided tumor localization (p=0.0002), but not with overall survival (log rank, p=0.566). CONCLUSION: Our data suggest that sporadic CRCs with MSI/LOH are more aggressive, develop earlier and progress faster to more advanced stage. The most frequent cause of failure of DNA MMR system appeared to be the hypermethylation of CpG islands of the promoter region of MLH1, whereas the methylation of MSH2 was a rare event.

Emergence of the active site of spleen exonuclease upon association of the two basic monomers of the tetrameric enzyme.

The 5'-->3' exonuclease from beef spleen is a 160-kDa tetramer consisting of four subunits of two types. Partial reduction of the tetramer led to one stable intermediate state of the enzyme with Mr = 80 kDa. The aim of this paper was to attribute the exonucleolytic activity to one of the two monomers, to the dimer or to the tetramer. The different forms of the exonuclease were separated by SDS-polyacrylamide gel electrophoresis, transferred on an Immobilon-P membrane and subsequently renaturated. Antibodies monospecific against each of the two monomers as well as against the dimer were isolated and their inhibitory effect on the holoenzyme determined. It was found that after renaturation the two monomers did not possess any exonuclease activity while the 80-kDa dimer showed a lower recovery of the specific activity of the enzyme (20.8+/-0.23 nkat/nmol, (n = 5)) in comparison with the 160-kDa tetramer (64.8+/-0.75 nkat/nmol (n = 5)). It was demonstrated that the antibodies monospecific against the dimer caused 53% maximum inhibition of the 160-kDa exonuclease. The antibodies monospecific against 25- and 55-kDa monomers did not inhibit the activity of the holoenzyme. No single-strand endonuclease activity of the spleen exonuclease was observed when using supercoiled Bluescript KS+ plasmid DNA as a substrate. This data suggest the emergence of an 80 kDa active form of beef spleen exonuclease upon association of two monomers of the tetrameric enzyme.

Oligomeric protein structure of beef spleen exonuclease.

A one-step purification of beef spleen exonuclease in the form of a DNA-enzyme complex is described. The purity of the exonuclease was verified by two-dimensional gel electrophoresis. It possesses molecular mass 160 kDa and pI 6.92. The one-dimensional sodium dodecyl sulfate gel after reduction with beta-mercaptoethanol suggests that the 160-kDa exonuclease consists of four polypeptide chains of two different types with molecular masses 55 and 25 kDa. The tetrameric structure of the exonuclease is supported by intermolecular disulfide bonds, and their partial reduction leads to the formation of one stable intermediate with molecular mass 80 kDa formed by binding one 55-kDa with one 25-kDa subunit into a dimer. During two-dimensional gel electrophoresis, the dimer showed pI 6.92 while monomers showed pI 6.78 for the 55-kDa and pI 6.29 for the 25-kDa. Two other intermediate states of two big and one small (135 kDa) and two small and one big subunit (105 kDa) were also visualized. They are unstable and easily dissociated into one 80-kDa dimer and either one 55-kDa or one 25-kDa monomer. The immunoblotting analysis with specific polyclonal antibodies against 160-kDa protein confirmed the subunit structure of the exonuclease. It was found that both monomers are glycosylated.

Search for Extrapancreatic Effects of New Oral Hypoglycemic Agent A-4166: 1. Oral Glucose Tolerance Tests in Normal and Hereditary Insulin Resistant Rats.

OBJECTIVE: To test the effect of new oral hypoglycemic compound A-4166 on insulin secretion during oral glucose challenge in normal and hereditary non-obese, hypertriglyceridemic, insulin resistant and hypertensive rats fed either a normal or high fat diet. METHODS: The rats used were 15 weeks old males of Wistar Charles River strain (controls) and Wistar-derived hereditary hypertriglyceridemic (hHTg) rats of our own colony. They were fed either basal (12 cal% of fat) or high fat diet (70 cal% fat). After 3 weeks of feeding the above diets, the oral glucose tolerance tests (2 g/kg) were carried out in unrestrained conscious rats kept in special metabolic cages after overnight fasting and ten minutes after the administration of A-4166 (100 mg/kg) or placebo by the stomach tube. Plasma glucose, triglycerides, free fatty acids and insulin levels were measured by routine analytical methods. RESULTS: High fat diet feeding resulted in an increase in fasting plasma insulin in both rat strains, while fasting plasma glucose in high fat diet fed animals remained unchanged as compared to those fed basal diet. No differences in the fasting FFA levels were found. The glucose area under curve (AUC) did not differ between the two strains used and high fat diet resulted in a higher glucose AUC in both strains. The administration of A-4166 improved the glucose tolerance in all animals, namely in those fed the basal diet. Insulin AUC showed very similar pattern in both rat strains proving the stimulatory effect of A-4166 on insulin secretion during an oral glucose challenge. High fat feeding resulted in an impairment of insulin action, but the administration of A-4166 restored the antilipolysis in both strains to the normal range. CONCLUSIONS: The previously reported hypoglycemic action of A-4166 resulting from the increased insulin secretion was confirmed. Moreover, some beneficial action of A-4166 on antilipolysis in vivo was demonstrated.

The effect of the new oral hypoglycemic agent A-4166 on glucose turnover in the high fat diet-induced and/or in the hereditary insulin resistance of rats.

A-4166, a phenylalanine derivative, is a hypoglycemic agent, which has been shown to improve blood glucose levels mainly due to the rapid and short term stimulation of insulin release. Nevertheless, a possible extrapancreatic action of A-4166 has not yet been investigated. Therefore, insulin action (euglycemic hyperinsulinemic 6.4 mU.kg-1.min-1 clamp plus 3H-2-deoxyglucose tracer administration) was studied after 3 weeks on either standard (BD) or high fat (HF) diet in normal control (C) or in hereditary insulin resistant (hHTg) rats which were given a single dose of A-4166 (10 mg per kg BW, i.v.) 60 min after clamp commencement. HF feeding reduced the glucose infusion rate (GIR) required to maintain euglycemia to about 50% of C (p < 0.001). In hHTg rats, HF did not further pronounce the pre-existing decrease of GIR of hHTg animals fed BD. A-4166 changed GIR neither in C, nor in the hHTg group. The estimated glucose disposal (Rd) (C-BD: 32.3 +/- 1.9 vs C-HF: 25.5 +/- 1.9 mg.kg-1.min-1, p < 0.001) and glucose metabolic index (Rg') in skeletal muscles (Q. femoris: C-BD: 25.6 +/- 1.5 vs C-HF: 12.3 +/- 1.1 mmol.100 g-1.min-1, p < 0.001) were reduced by HF in control rats but were not restored by a concomitant bolus of A-4166. Nevertheless, in hHTg rats fed the HF diet a single dose of A-4166 brought back their Rd (hHTg-HF: 23.5 +/- 1.3 vs hHTg-HF plus A-4166: 31.0 +/- 3.5 p < 0.03) and Rg' (Soleus muscle: hHTg-HF: 29.2 +/- 3.2 vs hHTg-HF plus A-4166: 41.3 +/- 4.0) to values of the control group on BD. In summary, a) a single bolus administration of A-4166 to the control or to the insulin resistant hHTg rats, fed either the BD or HF diets, did not abolish the reduction of GIR required to maintain euglycemia during hyperinsulinemic clamps; b) nevertheless, A-4166 caused a significant increase of the estimated plasma glucose disposal (Rd) and skeletal muscle glucose metabolic index (Rg') of hHTG rats fed the HF diet; c) we suggest that A-4166 may have an extrapancreatic action but this needs to be proven using a long-term administration plan of A-4166.

Single-strand-specific DNase activity is an inherent property of the 140-kDa protein of the snake venom exonuclease.

Polyclonal antibodies against the exonuclease from Crotalus adamanteus venom (the 140-kDa protein) inhibit both the exonucleolytic and the single-strand-specific endonucleolytic activities, present in the exonuclease preparation. The antibodies also diminish the ability of the enzyme to split the negatively supercoiled Bluescript KS+ in the AT-rich fragment near-by the transcription termination site of the Ampicillin gene. Therefore the single-strand-specific endonucleolytic activity was attributed to the protein molecule of the exonuclease. The processivity of the exonucleolytic action was found to be less than 3 monomers as indicated by the heparin trapping method.

Decreased glucose transporter protein (GLUT4) in skeletal muscle of hypertriglyceridaemic insulin-resistant rat.

Protein levels (Western blot) of the major glucose transporter isoform (GLUT4) were measured in skeletal muscles (quadriceps femoris) of an animal model of human metabolic syndrome X, i.e. the hereditary hypertriglyceridaemic (HTG) insulin-resistant rats fed various diets. The results were compared with the data obtained in normal Wistar rats which underwent the identical protocol. In HTG rats fed the basal diet (B) or high-sucrose diet (HS) (known to induce hypertriglyceridaemia and to impair insulin action), a decrease of GLUT4 protein levels (B: Control 100 +/- 3 vs HTG 46 +/- 5%, p < 0.005; HS: Control 80 +/- 9 vs HTG 49 +/- 3%, p < 0.005) was observed. Furthermore, marine fish oil (FO) rich in n-3 polyunsaturated fatty acids (PUFA), added to the basal diet (30 wt % of n-3 PUFA) reduced the GLUT4 protein levels (B: 100 +/- 3 vs B+FO: 42 +/- 4%, p < 0.005) in control rats to values similar to those found in HTG rats (B: 46 +/- 4%). However, dietary FO did not have any effect in HTG rats (49 +/- 3%). Feeding the high-sucrose diet supplemented with FO to both the control and HTG rats was followed by a further decrement of GLUT4 protein (Control 15 +/- 5 vs HTG 14 +/- 4%). In conclusions, a) the hereditary HTG rats had by about 50% lower GLUT4 protein levels in the quadriceps femoris muscle in comparison to normal Wistar rats; b) high-sucrose diet or raised dietary intake of n-3 PUFA did not further alter the number of glucose carriers in quadriceps femoris muscle in HTG rats and c) feeding the high-sucrose diet with higher proportion of n-3 PUFA was associated with an additional reduction of the GLUT4 protein level in this muscle.

Modulation of the hypolipidemic effect of fish oil by inhibition of adipose tissue lipolysis with acipimox, a nicotinic acid analog.

To assess the possible benefits of combined hypolipidemic therapy (acipimox+marine fish oil) on lipid and lipoprotein metabolism, male Wistar rats were fed for 14 days a high sucrose diet (70 cal% sucrose) alone or a high sucrose diet supplemented with acipimox (0.2 g/100 g diet) and/or fish oil (1 ml orally daily; 30 wt% of n-3 PUFA). Feeding a high sucrose diet increased (control: 61 +/- 6 vs HS: 110 +/- 8 nmol.min-1.mg-1, p < 0.001) the activity of acetyl CoA carboxylase in the liver, this was normalized by fish oil but not acipimox alone (HS+FO: 68 +/- 4; HS+ACI: 95 +/- 4; HS+ACI+FO: 71 +/- 2 nmol.min-1.mg-1). Increased triglyceride concentration in serum and muscle tissue (m. soleus and heart) of high sucrose-fed animals was suppressed equally by fish oil, acipimox, and/or both. The cholesterol-lowering effect of fish oil was also present in the liver (p < 0.005). The cholesterol-lowering action of acipimox was accompanied by the accumulation of cholesterol in the liver (p < 0.005), whereas the combination of acipimox+fish oil did not change the liver cholesterol content. After fish oil the LDL binding capacity of liver plasma membranes was increased 1.6-fold (p < 0.001). LDL receptor activity was significantly decreased in HS+ACI group (p < 0.05), but remained unchanged in HS+FO+ACI-fed animals. In summary, (a) the hypotriglyceridemic effect of fish oil in high sucrose-induced HTG is due to its inhibitory effects at the level of fatty acid synthesis; (b) decreased triglyceride production and output from the liver prevent triglyceride accumulation in muscle tissue; (c) the cholesterol-lowering action of acipimox but not fish oil was accompanied by an accumulation of cholesterol in the liver; (d) the latter phenomenon may be due to the opposite effects of both drugs on cholesterol catabolism via hepatic LDL receptors.

Muscle GLUT 4 protein levels and impaired triglyceride metabolism in streptozotocin diabetic rats. Effect of a high sucrose diet and fish oil supplementation.

Our data indicate that (a) the existence of a defect in the clearance of circulating TG and persistence of muscle TG deposition in the high sucrose-fed neonatal streptozotocin diabetic rat, which (b) can only be partially corrected by raised dietary n-3 PUFA intake. (c) Skeletal muscle of STZ type II-like diabetic rats contains about 40% less glucose transporters, and (d) this situation cannot be changed by any of the dietary treatments employed. (e) These findings indicate that muscle TG accumulation may have no direct relation to glucose transport in muscle.

Effect of dietary fish oil on 2-deoxy-D-3H glucose uptake in isolated adipocytes of rats fed various diets.

High sucrose diet-induced insulin resistance and mild glucose intolerance are associated with decreased insulin binding to isolated adipocytes and reduced insulin action in adipose tissue. Enhanced dietary intake of omega-3 polyunsaturated fatty acids (n-3-FA) counteracts these disorders. To provide more information on the possible role of membrane-related glucose transport processes, basal and insulin-stimulated 2-deoxy-D-3H glucose uptake was evaluated in isolated adipocytes obtained from rats on various dietary regimens. For 2 weeks animals were fed three different isocaloric (18 cal% proteins, 19 cal% fat, and 63 cal% carbohydrate) diets: (1) a standard rat chow (B), (2) a high sucrose diet (S, 63 cal% sucrose), or (3) an S diet supplemented with marine fish oil (S + FO, Martens, 30 wt% of n-3-FA). High dietary n-3-FA intake resulted in a significant decline in both basal (0.05 +/- 0.01 pmol/10(6) fat cells; mean +/- SEM) and insulin-stimulated (10(-6) M) (0.20 +/- 0.01) glucose uptake when compared with the control (basal: 0.12 +/- 0.02; insulin: 0.35 +/- 0.02) and/or the S group (basal: 0.18 +/- 0.03; insulin: 0.43 +/- 0.03), indicating decreases in insulin responsiveness and sensitivity (ED50: B: 0.03 +/- 0.01; S: 0.03 +/- 0.01; S + FO: 0.73 +/- 0.2 nM; p < 0.01 for S + FO vs B and S + FO vs S). Fish oil supplementation induced an increase in adipocyte size (B: 69 +/- 1.6; S: 70 +/- 2.5 and S + FO: 76 +/- 2.2 microns; B: S + FO p < 0.05) and a decrease in plasma membrane microviscosity (B: 4.08 +/- 0.3; S: 5.39 +/- 0.5; S + FO: 3.10 +/- 0.3; p < 0.05). Rates of basal and insulin-stimulated glucose uptake did not correlate with plasma membrane microviscosity; however, a negative relation to fat cell size was found (r = -0.484; p < 0.05). On the other hand, a positive correlation between both basal (r = 0.504; p < 0.05) and insulin-stimulated (10(-6) M, r = 0.640; p < 0.02) glucose uptake and blood glucose levels was observed. In conclusion, these data (a) suggest a less important role of diet-induced changes in plasma membrane microviscosity for glucose uptake in adipose tissue, and (b) leave unclear the mechanism of why dietary fish oil decreases the sensitivity of glucose uptake to insulin in isolated rat adipocytes.

Effect of a low salt diet on blood pressure and vasoactive hormones in the hereditary hypertriglyceridemic rat.

In hereditary HTG rats, basal systolic blood pressure using tail-cuff sphygmomanometry was significantly higher (122.1 +/- 2.1 mm Hg; n = 16) than that in NTG animals (107.1 +/- 1.52; n = 16). A low salt diet did not influence blood pressure in NTG rats during the consecutive 4 weekly periods. However, in the second week blood pressure in HTG rats rose significantly in both the control rats on a normal salt diet and those on a low salt diet (132.5 +/- 1.89, n = 8, and 132.6 +/- 1.93, n = 8). No further changes were registered in the third and fourth week in control HTG rats. On the other hand, blood pressure fell significantly in HTG rats on a low salt diet in the third week in comparison with the second week (119.5 +/- 3.2, n = 8), and it increased again in the fourth week (123.0 +/- 2.35, n = 8). Hormones in plasma were determined at the end of the experiment. Plasma levels of norepinephrine were not influenced by differences in salt intake and were significantly higher by about 45% in HTG than in NTG animals. The lowest concentration of corticosterone in plasma was found in control HTG rats (1.2 +/- 0.2 vs 4.6 +/- 0.8 micrograms/100 ml in control NTG rats). Nevertheless, corticosterone concentration increased in HTG rats on a low salt diet at comparable values found in NTG rats on a low salt diet (3.1 +/- 0.8 vs 4.3 +/- 1.5). Plasma renin activity and plasma aldosterone concentrations were not different in the NTG and HTG groups and were uninfluenced by the diets (Table 1). We conclude that the elevated blood pressure in HTG rats and its variations during the experiment may reflect more pronounced sympathetic activity in HTG rats rather than blood pressure dependency on different salt intake.