Tissue Inhibitors of Metalloproteinase 1 (TIMP-1) and 3 (TIMP-3) as New Markers of Acute Kidney Injury After Massive Burns

BACKGROUND Acute kidney injury (AKI) is a common and serious complication after massive burn injury. One of the postulated etiologies is destruction of the extracellular matrix of nephrons, caused by a local imbalance between matrix metalloproteinases (MMPs) and specific inhibitors. The aim of this study was to analyze the dynamics of tissue inhibitors of metalloproteinases (TIMPs) during the first 5 days after massive thermal injury and the relationship with the risk of AKI. MATERIAL AND METHODS Thirty-three adults (22 men, 11 women) with severe burns were enrolled in the study. The values of TIMPs 1 to 4 were measured in blood serum and urine using the multiplex Luminex system. The associations between TIMPs and the risk of AKI were analyzed by using the generalized linear mixed models for repeated measurements. RESULTS Significant changes in serum and urine activities of TIMPs were confirmed, especially during the first 2 days after burn injury. Almost half of patients presented renal problems during the study. Significant differences between values of TIMPs in AKI and non-AKI status were also observed. However, a significant relationship between concentration of TIMPs and risk of AKI was confirmed only for urine TIMP-1 and serum TIMP-3. CONCLUSIONS The evaluation of TIMPs in the early stage after burn injury has potential benefits. The important roles of urine TIMP-1 and serum TIMP-3, as novel markers of the risk of AKI development, were confirmed. Other parameters require further analysis.

P0641ANALYSIS OF ACUTE KIDNEY INJURY PROGNOSTIC FACTORS IN SEVERELY BURNED PATIENTS (PRELIMINARY RESULTS)

Background and Aims

AKI is one of the most common and severe complications in severely burned patients. However, it’s aetiology, risk factors, clinic course, treatment and prognostic is still not very clear. The aim of the study was to analyse of incidence, clinic course and risk factors of the Acute Renal Injury (AKI) after massive burn injuries.

Method

33 patients (pts); 11 (33,3%) females, 33 (66,7%) males; admitted to the hospital due to severe burn injury (total body surface area TBSA ≥15%) were involved in the study from 01.01.2017 till 30.06.2019. Mean age of the group was 48,3 (±18,8) years. Patients admitted to the hospital later than 72 hours after injury were excluded from the project. Mean time-period from the injury to the admission time was 2,1 (±0,9) hours. Mean injured skin surface was 42,2 (±18,1%) of the TBSA, the 3rd degree of burn was confirmed at 21 (63,6%) pts, respiratory tract was injured at 23 (69,7%) pts. None of the pts presented symptoms of chronic kidney disease before the injury. Basic life parameters, diuresis and chosen biochemical parameters (i.e. renal function) were measured at each patient once daily from admission till 7th day. Additionally the concentration of chosen novel AKI biomarkers (CystatinC, Neutrophil gelatinase-associated lipocalin, Kidney injury molecule-1, Interleukin-6 and 18, Insulin-like growth factor-binding protein 7, Tissue inhibitors of metalloproteinases 1÷4) were also measured in urine and blood sample during each first 3 day of hospitalisation and compared with the standard renal function parameters. Mean time of the 1st measurement was 44,7(±17,7), the 2nd - 70,8 (±19,2) and 3rd - 94,8 (±19,2) hours after injury. AKI criteria were as follows: decrease in glomerular filtration rate (GFR) of less than 60 ml/min at admission, decrease in GFR of more than 75% compared to baseline, decrease in the daily diuresis of less than 500 ml/24 hours.

Results

The medium hospitalisation time was 28,1(±21,5) days. During observation time, clinical and biochemical symptoms of AKI were confirmed in 20 pts (60,6%). 8 (24,2% of all, 40,0% with AKI) required renal replacement therapy RRT: 37,5% (3 pts) - intermitted haemodialysis, 25,0% (2 pts) - continuous veno-venous haemodiafiltration and 37,5% (3 pts) – both methods. AKI developed usually in 3rd day of hospitalisation (maximum in 19th) and RRT usually started at the 8th day (maximum at 20th). The overall mortality was 48,5% (16 pts), 70,0% (14 pts) with AKI and 87,5% (7 patients) in RRT group. Death usually occurred at the 19(±15) day after injury. 2 (12,5%) pts died from hemodynamic disorders in first 7 days, in 59 and 120 hour respectively. There were 14 (87,5%) pts in the group of late mortality (more than 7 days after injury), mean time of death was 24,5 (±15) days, in 57,1% connected with severe infection. The major causes of death in all were: cardiac arrest 14 (87,5%), cardiovascular failure 8 (50,0%), burn/septic shock 5 (37,5%), or respiratory failure 2 (12,5%) pts. The confirmed risk factors of AKI and mortality were injury more than 15% of TBSA, 3rd degree of burn injury age >65 years old, hemodynamic instability demanding catecholamine (p<0,05). AKI was also confirmed as an independent risk factor of mortality (p=0,004). The early analysis suggest potentially benefit of using novel biomarkers AKI in the clinic practise with superiority over standard AKI parameters (the final results of collected data analysis are still in progress).

Conclusion

AKI is a frequent and important problem in severely burned patients. The occurrence of AKI significantly worsens the prognosis for survival. It is predicted by such factors as injury more than 15% of TBSA, 3rd degree of burn injury, older age and hemodynamic instability. Assessment of renal function, including novel AKI biomarkers, is an important prognostic factor after thermal injury and should be routine evaluated during treatment of burned patient.

FRAX prognostic and intervention thresholds in the management of major bone fractures in hemodialysis patients: A two-year prospective multicenter cohort study

PURPOSE

The usefulness of FRAX in predicting major bone fractures in patients with end-stage kidney disease on maintenance hemodialysis treatment has been confirmed in previous studies. For meaningful clinical use, the prognostic and intervention FRAX thresholds need to be established.

METHODS

The primary aim of our study was to calculate the optimal cut-off point of FRAX for the best prediction of an increased bone fracture risk in dialysis patients and additionally, to propose its intervention threshold, indicating the need for antifracture pharmacological treatment. The study included 718 hemodialysis patients, who were followed up for two years. Thirty low-energy major bone fractures were diagnosed during the study period. We used the Polish version of FRAX (without the DXA examination) and some particular variables of the FRAX calculator. The optimal cut-off point for prediction of an increased major bone fracture risk was based on the analysis of the sensitivity and specificity curves of FRAX.

RESULTS

The analysis revealed FRAX >5% (sensitivity of 70.0%, specificity of 69.8%) as the prognostic threshold for major bone fractures. Its sensitivity for bone fracture prediction was significantly higher, but specificity lower than those of FRAX ≥10%, used in general Polish population. The reason for this can be an underestimation of bone fracture risk with FRAX in dialysis patients.

CONCLUSIONS

We conclude that the FRAX prognostic threshold for identification of an increased risk of major bone fractures in hemodialysis patients is >5%. We propose to use this specific value of FRAX as an intervention threshold for pharmacological antifracture treatment in hemodialysis patients.

Early and Late Acute Kidney Injury in Severely Burned Patients

Background

This study evaluated factors influencing early and late occurrence of AKI in severely burned patients and assessed the relationship between time of occurrence of AKI and mortality of AKI patients.

Material/Methods

Renal function was evaluated at 3 time points: at admission, at the critical point or middle point of hospitalization, and at the endpoint for which death or a discharge from the center was considered. AKI criteria were: decrease in GFR of less than 60 ml/min at admission, decrease in GFR of more than 75% compared to baseline, and decrease in the daily diuresis of less than 500 ml/24 h.

Results

At admission, 15.1% of the patients had eGFR <60 ml/min. AKI occurred in 38.5% of cases. The occurrence of AKI was associated with: elderly age (p<0.001), female sex (p=0.017), overweight and obesity (p=0.055); extent and depth of burns, respiratory failure, low protein concentration (for all p<0.001), low blood pressure (p=0.014), and high WBC (p=0.010). Early AKI was detected in 28% of patients. Mortality was 100% with the initial GFR ≥60, 100% with the initial GFR <60 and early deterioration of renal function, 80% with the initial GFR <60 and late worsening, and 60% with the initial GFR <60 and no worsening. Late AKI was observed in 10% of patients and mortality in this group was 79.2%. Mortality in the entire group with AKI was 88.0% versus 24.5%.

Conclusions

The frequent occurrence of AKI, especially early, worsens the prognosis for survival. Assessment of renal function should be included in the prognostic scales for burned patients.

[Case of young woman with Graves' disease and incomplete distal renal tubular acidosis with severe progress and cardiac arrest]

Diagnostic of renal tubular disorders can be often difficult. Incomplete form of distal Renal Tubular Acidosis (dRta) in course of Graves' disease was de novo recognized in a young woman hospitalized with a deep deficiency of potassium in blood serum complicated with cardiac arrest. Series of tests assessing the types and severity of water-electrolyte, acid-base and thyroid disorders were performed during a complex diagnosis. During the treatment of acute phase of the disease we intensified efforts to maintain basic life functions and to eliminate deep water-electrolyte disturbances. In the second phase of the treatment we determined an underlying cause of the disease, recognized dRTA, and introduced a specific long-term electrolyte and hormonal therapy. To confirm the diagnosis oral test with ammonium chloride (Wrong-Davies' test) was performed. After completion of the diagnostic and therapeutic process, the patient was included in the nephrological supervision on an outpatient basis. The basic drug for the therapy was sodium citrate. After a year of observation and continuing treatment we evaluated therapeutic results as good and permanent.

Dental caries in rats associated with Candida albicans

In addition to occasional opportunistic colonization of the oral mucosa, Candida albicans is frequently found in carious dentin. The yeast's potential to induce dental caries as a consequence of its pronounced ability to produce and tolerate acids was investigated. Eighty caries-active Osborne-Mendel rats were raised on an ampicillin-supplemented diet and exposed to C. albicans and/or Streptococcus mutans, except for controls. Throughout the 28-day test period, the animals were offered the modified cariogenic diet 2000a, containing 40% various sugars. Subsequently, maxillary molars were scored for plaque extent. After dissection, the mandibular molars were evaluated for smooth surface and fissure caries. Test animals exposed to C. albicans displayed considerably more advanced fissure lesions (p < 0.001) than non-exposed controls. While S. mutans yielded similar results, a combined association of C. albicans and S. mutans had no effect on occlusal caries incidence. Substituting dietary sucrose by glucose did not modify caries induction by C. albicans. However, animals fed a diet containing 20% of both sugars showed no differences to non-infected controls. Smooth surface caries was not generated by the yeast. This study provides experimental evidence that C. albicans is capable of causing occlusal caries in rats at a high rate.

Microbial ingrowth around single- and multi-component adhesives studied in vitro

The aim of this study was to compare the in vitro microbial leakage in 4 micro-hybrid composites in combination with 4 single-component dental adhesives (Scotchbond 1/Z100 MP = group 1; Syntac Single-Component/Tetric Flow = group 3; OptiBond Solo/XRV Herculite = group 5; Solobond M/Arabesk Top = group 7) and 4 multi-component dental adhesives (Scotchbond Multi-Purpose/Z100 MP = group 2; Syntac/Tetric Flow = group 4; OptiBond FL/XRV Herculite = group 6; Solobond Plus/Arabesk Top = group 8). Ninety-four mixed standardized Class V cavities of human caries-free extracted premolars were filled with eight different composite adhesive systems using a one-layer (groups 1-4) or a two-layer technique (groups 5-8). After thermocycling and incubation in a broth culture of Streptococcus mutans and Lactobacillus acidophilus, followed by decalcification and staining, the extent and the type of microbial leakage were measured histologically. The extent of microbial leakage in the composite restorations was very low in all groups and there were no significant differences between adhesives. Z100 MP in combination with single- and multi-component adhesives showed a significantly higher microbial leakage than Tetric Flow systems (U test: p=0.037). XRV Herculite adhesive systems showed significantly less extensive microbial leakage than Arabesk Top adhesive systems (U test: p<0.001). The single-component dental adhesives achieved a marginal adaptation of composites comparable to that of multi-component adhesives in vitro.

[Lifestyle, living conditions and health status--a cross-sectional study of the Saxon population in the period 1993 to 1994]

The aim of this cross-sectional study was to record the living conditions, lifestyle variables and health status in a part of the population of Saxony and to examine statistical relationships between the three categories. The interview by post took place from March 1993 to August 1994. The sample consisted of 602 participants, i.e. a return of 52.3%. The survey proved conditionally representative for the population of Saxony. Statistical methods used were Chi2 test, H test, Spearman correlation and multiple regression procedures. Males and females showed clear differences in their lifestyles and in the state of health. It was found that the lifestyle was associated with age. The following variables were significantly associated with the subjective health status: sex, daily routine, number of negative life events, utilisation of preventive measures, contentment, age, and domicile. Significant connections were found between the objective health status (number of chronic diseases) and the variables: utilisation of preventive measures, number of negative life events, employment, daily routine, smoking, alcohol consumption, contentment, and age. In the statistical relationship the primary health status had the most distinct influence on the lifestyle and this covered the influence of lifestyle on health status.

Antibacterial effects of Nd:YAG laser irradiation within root canal dentin

The microbial flora of the root canal dentin can cause failures in the conventional treatment of infected root canals if it cannot be sufficiently removed by preparation and chemical disinfection of the root canal. The aim of this study is to examine the bactericidal effects of neodymium:yttriumaluminum garnet (Nd:YAG) laser irradiation in the depth of the root canal dentin. Following sterilization, longitudinal section dentin slices of different thicknesses (100-1000 microns) were inoculated on one side with 4 microliters of a Streptococcus mutans suspension. The opposite sides of the dentin slices were then irradiated four times for 10-20 sec (according to the sample area) using the Nd:YAG laser at a setting of 1.5 W, 15 pps with a 200 microns glass fiber from an angle of about 5 degrees. The bacteria were then removed from the dentin using vibration and plated out on culture dishes that were selective for Streptococcus mutans. When compared with untreated control slices, counting of the colonies revealed a highly significant elimination of bacteria for all thicknesses following laser irradiation. Although the intensity of the laser irradiation decreased after penetration of a 1000-micron dentin slice, the bactericidal mode of action was still effective.

[Oral health behavior and state and the effect and necessity of dental care in young and medium adults (Dresden prevention study)]

In a baseline examination of a preventive study 319 randomly recruited patients of a dental school aged between 16 and 35 years were inquired about oral health behavior and the oral health state was determined clinically. The spectrum of methods included extended anamnesis, plaque index according to Silness/Löe, DMF/T- and GPM/T-index. The health behaviour and the derived preventive and curative care needs show that the majority of patients need individual oral hygiene and nutrition advising, professional oral hygiene measures, fluoride application, as well as filling therapy. Early therapy of periodontitis is of importance.

[Chlorhexidine in the treatment of root canal infection and its sequels]

The plaque inhibitor chlorhexidine digluconate was used for intra- and transcanal irrigation in the endodontic treatment triad for periapical lesions (circumscribed, diffuse, fistulating, cystic, suspected cystic lesions). 50 patients were followed up by clinical and standardized radiologic studies. In another 18 patients microbiologic criteria were also used. 16 root canals showed pretreatment infection with mixed aerobic and anaerobic organisms. Mechanical preparation of the root canals with or without extension of the foramen and triple irrigation with 0.5% chlorhexidine digluconate produced clinical relief of symptoms (49 pts.), sterility (14 of 18 pts.) and reduction of the size of periapical lesions (12 pts.). At a mean follow-up of 24 months 30 patients have so far shown complete restitution of periapical bone.

[Toxicity of different endodontic antiseptics]

The median lethal dose (LD 50) of endodontic antiseptics sodium hypochlorite, chloramine and chlorhexidine digluconate was determined in experiment on albino mice using the method described by Litchfield and Wilcoxon. Sodium hypochlorite and chloramine have shown a twice stronger toxic effect than chlorhexidine digluconate. The difference was significant.

[Antimicrobial effect of endodontic antiseptics]

The endodontic antiseptics chloramine, sodium hypochlorite and chlorhexidine digluconate were evaluated for antimicrobial effect by a complex of susceptibility testing. In the agar diffusion test, tube dilution test and plate flooding test chlorhexidine digluconate was the most efficient agent against isolates of infected root canal.

[The effect of various caries preventive agents on the microflora of albino rats]

An experiment with 80 Wistar rats was performed to study, using cultural methods, the effect of locally and internally applied caries-preventive agents on the microbiological situation in the oral cavity and on the surface of the skin. Especially in case of combined internal and local application, fluoride-containing preparations exerted an inhibitory effect on the oral microflora that had been altered by a cariogenic diet and on the bacterial invasion of the skin. The influence of a locally applied mineral solution on bacterial growth was only insignificant.