Effects of Oral Glucose on Intermediary Metabolism in Continuous Ambulatory Peritoneal Dialysis Patients versus Healthy Subjects

Objective

To explore the mechanisms and metabolic consequences of the insulin resistance of patients treated by continuous ambulatory peritoneal dialysis (CAPD).

Design

CAPD patients and healthy subjects ingested a similar mean oral glucose load per kilogram of fat-free mass (FFM) [1.20 ± 0.03 g/(kg FFM) vs 1.20 ± 0.06 g/(kg FFM); CAPD vs healthy subjects]. Substrate oxidation was monitored over 6 hours using indirect calorimetry.

Setting

Peritoneal dialysis unit of a tertiary-care institutional center.

Outcome Measures

Glycemia, insulinemia, substrate oxidation.

Patients

Six CAPD patients (68 ± 5 yr) and 6 healthy subjects (24 ± 1 yr). The CAPD patients had similar body mass index (21.4 ± 1.3 vs 22.9 ± 1.1 kg/m2), a higher percent fat (25.8% ± 3.7% vs 16% ± 2.2%; p < 0.05), and a lower FFM (42.2 ± 2.2 kg vs 56.5 ± 2.6 kg; p < 0.01) than healthy subjects.

Results

The CAPD patients displayed a higher glycemic and insulinemic responses to glucose than did healthy subjects (p < 0.05), but similar glucose oxidation and storage. Lipid oxidation and plasma nonesterified fatty acids were not increased in CAPD patients versus healthy subjects, in spite of a higher adiposity. Fat oxidation was related to fat mass in CAPD patients (r2 = 0.77, p < 0.05) but not in healthy subjects (r2 = 0.05).

Conclusion

CAPD patients display an insulin -resistance not explained by an increased lipid oxidation. The maintenance of intracellular glucose utilization at the expense of higher glycemic and insulinemic responses suggests a defective glucose transport.

Contagious agalactia monitoring in caprine herds through regular bulk tank milk sampling

Surveillance and control of Mycoplasma spp. responsible for contagious agalactia (CA) in caprine herds are important challenges in countries with a large small-ruminant dairy industry. In the absence of any clinical signs, being able to determine the potential circulation of mycoplasmas within a herd could help to prevent biosecurity issues during animal exchanges between farms and improve health management practices. The objective of this study was to determine whether regular sampling of bulk tank milk was suitable for such surveillance. Twenty farms were sampled once a month for 2 yr and CA-responsible mycoplasmas were detected by real-time PCR on DNA extracted from milk, using 3 different DNA extraction methods. The pattern of mycoplasma excretion in bulk tank milk was assessed over time and several herd characteristics were recorded together with any event occurring within the herds. In general, the results obtained with the different detection methods were comparable and mainly agreed with the culture results. Several patterns of excretion were observed but were not related to herd characteristics (size, breed, and so on). Recurrence of the same (sub)species and same pulsed-field gel electrophoresis subtype during the 2-yr period is indicative of the considerable persistence of mycoplasmas. This persistence was associated with intermittent excretion. In conclusion, bulk tank milk sampling could be valuable for controlling CA in caprine herds provided it is repeated several times, yet to be defined, per year and analyzed using an appropriate methodology and the right cut-off for interpretation.

Prevalence of tick-borne pathogens in adult Dermacentor spp. ticks from nine collection sites in France

The importance of Dermacentor spp. in the transmission of tick-borne pathogens is not well recognized in Europe. To investigate the role of Dermacentor spp. in the transmission of tick-borne pathogens, questing ticks were collected in 9 sites from southern to northwestern France (Camargue Delta to Eastern Brittany) where Dermacentor spp. exist and tick-borne diseases had occurred previously. Three tick species were collected during the spring and autumn of 2009. Collected ticks (both males and females) included D. marginatus (n=377), D. reticulatus (n=74), and I. ricinus (n=45). All ticks were analyzed by PCR or reverse line blot for the presence of pathogens' DNA. Pathogens analyzed were based on veterinarian reports and included Anaplasma phagocytophilum, Coxiella burnetii, Anaplasma marginale, Borrelia burgdorferi, Bartonella spp., Babesia spp., Theileria spp., and Francisella sp. Francisella tularensis was not detected in any of the analyzed ticks. In D. marginatus, infection prevalence for A. phagocytophilum (3%) was similar to that found in I. ricinus in Europe. Other pathogens present in D. marginatus included A. marginale (0.5%), Bartonella spp. (9%), C. burnetii (12%), F. philomiragia (1.3%), and Theileria annulata/Babesia bovis (0.3%), which were detected for the first time in France. Pathogens detected in D. reticulatus included A. marginale (1%), Bartonella spp. (12%), C. burnetii (16%), Borrelia spp. (1.5%), and F. philomiragia (19%). Pathogens detected in I. ricinus included A. phagocytophilum (41%), Bartonella spp. (9%), C. burnetii (18%), A. marginale (1%), Borrelia spp. (4.5%), and Babesia sp. (7%). This study represents the first epidemiological approach to characterize tick-borne pathogens infecting Dermacentor spp. in France and that may be transmitted by ticks from this genus. Further experiments using experimental infections and transmission may be now conducted to analyze vector competency of Dermacentor spp. for these pathogens and to validate such hypothesis.

Detection by real-time RT-PCR of a bovine respiratory syncytial virus vaccine in calves vaccinated intranasally

Seventeen four- to five-week-old calves that were not shedding bovine respiratory syncytial virus (BRSV) were vaccinated intranasally against the disease and sampled by nasal swabbing on 16 different days for up to 20 days after vaccination. BRSV vaccine virus was detected in 15 of the 17 calves. Five of the calves were PCR positive on only one swab, eight were PCR positive on two to five swabs and two were PCR positive on more than five swabs. Twelve of the calves were positive only before day 14 and three were positive after day 14. The nasal shedding of BRSV vaccine virus was very variable.

[Demography of nephrologists in France in 2002]

This survey was performed using data generated by a mailing sent with the collaboration of regional coordinators in 2002 to all the nephrologists identified in France. 1326 nephrologists were included in the pool, with an average of 22 nephrologists per million population (pmp), ranging from 14 to 29 pmp according to the different regions. Their mean (and median) age was 46.6 years, 30% were female. 63.5% of the nephrologists were working in a public hospital, 19.3% in private clinics, 13.3% in non-profit associations, 2% and 0.4% in research units or with industry, respectively. The data were used to generate a register of all the French nephrologists. 47 retirements per year are anticipated between 2010 and 2019, which yields an indication for the number of new nephrologists to be certified in this time-span. The gap between the future retirees and the newly trained nephrologists is very deep and cannot be bridged with the currently operating modes of recruitment. The increasing incidence and prevalence of patients with end stage renal failure will considerably increase the need of nephrologists, which is all the more amplified by the recent modification of the French law concerning the weekly upper limit of working time for physicians. Urgent measures have to be taken for preventing the consequences of dearth of nephrologists clearly anticipated for the next 10 years.

Acute metabolic effects of dialysis fluids during CAPD

Because the osmotic agents currently used for peritoneal dialysis, ie, glucose or amino acids, are also substrates, a metabolic transfer occurs during their peritoneal absorption. After the delivery of a 3.86% glucose dialysis solution, about 100% of the glucose absorbed through the peritoneal is oxidized. So, this glucose contributes fully to the energy load of the patients. Peritoneal glucose delivery also entertains hyperglycaemia and hyperinsulinaemia as compared to oral glucose. When compared to healthy subjects, oral glucose in continuous ambulatory peritoneal dialysis (CAPD) patients induces a higher glycaemic and insulinaemic response. This traduces insulin resistance in CAPD patients even after months of that renal replacement therapy. When amino acids are used in place of glucose in dialysis solution, they stimulate whole body protein turnover and are used mainly for protein synthesis. When a meal is coingested, protein breakdown is inhibited which reinforces the positive effect of the solution on protein balance.

Effects of an amino acid dialysate on leucine metabolism in continuous ambulatory peritoneal dialysis patients

BACKGROUND

Protein-energy malnutrition is frequent in continuous ambulatory peritoneal dialysis (CAPD) patients. The use of amino acids in the dialysate could improve the protein balance, especially if associated to a concomitant energy intake.

METHODS

A 1.1% amino acid solution for peritoneal dialysis was administered to CAPD patients over 30 minutes during concomitant absorption of 600 ml water (control study) or of a 600 kcal meal/600 ml. Leucine metabolism was studied using the combination of intravenous [2H3] and intraperitoneal [13C] leucine.

RESULTS

The rate of leucine appearance was stimulated by 56 and 53% (control and meal) at 45 minutes. The rates of leucine appearance and disappearance were lower from 180 to 300 minutes during the meal versus control study (P < 0.05). Proteolysis was unaffected during the control study and was inhibited by 25% during the meal study (P < 0.05). During the five-hour cycle dialysis with or without a meal, 80% of the leucine administered into the peritoneum was absorbed. Forty-one percent was retained in the splanchnic bed. Forty-three percent was used for protein synthesis, and 16% was oxidized.

CONCLUSIONS

This amino acids solution is efficaciously utilized for protein synthesis in CAPD patients with no effect on protein breakdown. The concomitant ingestion of a carbohydrate-lipid meal inhibits protein breakdown and reinforces a positive effect of the amino acids solution on protein balance.

Effects of severe protein restriction with ketoanalogues in advanced renal failure

OBJECTIVE

To compare a severe protein restriction diet supplemented with ketoanalogues to a moderate protein restriction diet in order to limit glomerular filtration rate (GFR) decrease in an advanced renal insufficiency stage.

DESIGN

Prospective randomised study conducted to compare a severe protein restriction diet (0.30 g/kg/day) supplemented with a preparation of ketoanalogues, hydroxyanalogues of aminoacids and aminoacids (Group A) to a moderate protein restriction diet (0.65 g/kg/day) (Group B).

PATIENTS

50 uremic patients included (25 in each group) with GFR is <20 mL/min/1.73m2.

RESULTS

There were no statistically significant differences between the two dietary regimens for the renal survival. But uremia decreased significantly in Group A (22.7+/-5.2 to 18.5+/-6.7 mmol/L) and increased in Group B (26.8+/-9.0 to 34.9+/-9.9 mmol/L). Calcemia increased in Group A from 2.28+/-0.18 to 2.42+/-0.17 mmol/L, p<0.01 with a stable phosphoremia while calcemia decreased in Group B (2.33+/-0.18 to 2.25+/-0.17 mmol/L, p<0.05). At the end of the study, Group A was different from Group B for calcemia (2.42+/-0.17 vs. 2.25+/-0.17 mmol/L, p<0.01), phosphoremia (1.39+/-0.30 vs. 1.80+/-0.65 mmol/L, p<0.02), alkaline phosphatase (61.42+/-22.93 vs. 78.8+/-27.0, p<0.05) and parathormone plasma levels (2.71+/-1.55 vs. 5.91+/-1.41 ng/mL, p<0.001).

COMMENTS

Compared to a moderate protein restriction (0.65 g/kg/day), a severe protein restriction (0.3 g/kg/day) supplemented by ketoanologues does not limit GFR decrease when GFR is below 20 mL/min/1.73m2, but improves phosphocalcic plasma parameters.

Effects of oral glucose on intermediary metabolism in continuous ambulatory peritoneal dialysis patients versus healthy subjects

OBJECTIVE

To explore the mechanisms and metabolic consequences of the insulin resistance of patients treated by continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

CAPD patients and healthy subjects ingested a similar mean oral glucose load per kilogram of fat-free mass (FFM) [1.20+/-0.03 g/(kg FFM) vs 1.20+/-0.06 g/(kg FFM); CAPD vs healthy subjects]. Substrate oxidation was monitored over 6 hours using indirect calorimetry.

SETTING

Peritoneal dialysis unit of a tertiary-care institutional center.

OUTCOME MEASURES

Glycemia, insulinemia, substrate oxidation.

PATIENTS

Six CAPD patients (68+/-5 yr) and 6 healthy subjects (24+/-1 yr). The CAPD patients had similar body mass index (21.4+/-1.3 vs 22.9+/-1.1 kg/m2), a higher percent fat (25.8%+/-3.7% vs 16%+/-2.2%; p < 0.05), and a lower FFM (42.2+/-2.2 kg vs 56.5+/-2.6 kg; p < 0.01) than healthy subjects.

RESULTS

The CAPD patients displayed a higher glycemic and insulinemic responses to glucose than did healthy subjects (p < 0.05), but similar glucose oxidation and storage. Lipid oxidation and plasma nonesterified fatty acids were not increased in CAPD patients versus healthy subjects, in spite of a higher adiposity. Fat oxidation was related to fat mass in CAPD patients (r2 = 0.77, p < 0.05) but not in healthy subjects (r2 = 0.05).

CONCLUSION

CAPD patients display an insulin-resistance not explained by an increased lipid oxidation. The maintenance of intracellular glucose utilization at the expense of higher glycemic and insulinemic responses suggests a defective glucose transport.

Glucose oxidation after a peritoneal and an oral glucose load in dialyzed patients

Glucose oxidation and thermogenesis were studied after a peritoneal (P) and an oral (O) glucose load in nine chronically uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD) for 24.4 +/- 5.8 months. The O load (50 g) given was equivalent to the amount of glucose absorbed over six hours through the peritoneum of the subjects (51.7 +/- 3.3 g). Glucose oxidation and energy expenditure were obtained using indirect calorimetry in basal state and over the six hours following the glucose load. Glucose oxidation rate was higher from 60 to 180 minutes after O than after P (P < 0.05), with peak values of 3.85 +/- 0.28 mg.kg-1.min-1 and 2.80 +/- 0.17 mg.kg-1.min-1 respectively (P < 0.05). Cumulated glucose oxidation over six hours was 53.6 +/- 0.6 versus 47.0 +/- 3.4 g after O and P respectively (NS). Glucose-induced thermogenesis was 8.7 +/- 2.9% versus 5 +/- 1.9% after O and P, respectively (NS). The route of administration of glucose induces different kinetics of the glucose oxidation rate, but a similar amount of glucose absorbed either by the peritoneum or by the gut contributes in a similar extent to glucose and energy balance.

[Demography of nephrologists in France]

This study used data from a mailing sent during years 1991-1992 to 1096 physicians. The response rate was 94%, providing a registry. The data showed the different kinds of diploma of the certified nephrologists. The vast majority of nephrologists ranges from 35 to 49 years old with a tendancy to be younger if they are working in a renal transplant unit. The number of retirement per year is given from 1993 to 2011 in order to evaluate the number of nephrologist to be certified in the future.