A Complex Evaluation of the In-Vivo Biocompatibility and Degradation of an Extruded ZnMgSr Absorbable Alloy Implanted into Rabbit Bones for 360 Days.

The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure-the removal of the plates and screws-can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface.

Zn-0.8Mg-0.2Sr (wt.%) Absorbable Screws-An In-Vivo Biocompatibility and Degradation Pilot Study on a Rabbit Model.

In this pilot study, we investigated the biocompatibility and degradation rate of an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. An alloy screw was implanted into one of the tibiae of New Zealand White rabbits. After 120 days, the animals were euthanized. Evaluation included clinical assessment, microCT, histological examination of implants, analyses of the adjacent bone, and assessment of zinc, magnesium, and strontium in vital organs (liver, kidneys, brain). The bone sections with the implanted screw were examined via scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). This method showed that the implant was covered by a thin layer of phosphate-based solid corrosion products with a thickness ranging between 4 and 5 µm. Only negligible changes of the implant volume and area were observed. The degradation was not connected with gas evolution. The screws were fibrointegrated, partially osseointegrated histologically. We observed no inflammatory reaction or bone resorption. Periosteal apposition and formation of new bone with a regular structure were frequently observed near the implant surface. The histological evaluation of the liver, kidneys, and brain showed no toxic changes. The levels of Zn, Mg, and Sr after 120 days in the liver, kidneys, and brain did not exceed the reference values for these elements. The alloy was safe, biocompatible, and well-tolerated.

The cytokine production of peripheral blood mononuclear cells reflects the autoantibody profile of patients suffering from type 1 diabetes.

Type 1 diabetes (T1D) is an autoimmune disorder characterised by the immune-mediated destruction of insulin-producing pancreatic beta cells. The inflammatory process appears to be primarily mediated by pro-inflammatory Th1 lymphocytes, while the role Th17 cells in T1D is currently being investigated. T1D is characterised by the presence of autoantigen-specific autoantibodies. This study was conducted using patients with confirmed T1D and healthy control subjects. We examined the effect of the patient's autoantibody profile on peripheral blood mononuclear cell (PBMC) cytokine production following stimulation with the major diabetogenic autoantigens GAD65 and IA2. IFN-gamma and IL17 production was detected by ELISPOT and the ratio of basic cellular populations in PBMCs was measured by flow cytometry. We demonstrated a significant interaction between the patient's autoantibody profile and mode of stimulation. This suggests that autoantigen stimulation has a different effect on different groups of patients depending on their autoantibody profile. An increased production of IL17 was found in patients with high IA2 autoantibodies compared to patients with low levels of autoantibodies and healthy controls regardless of the mode of stimulation. The titre of IA2 autoantibodies positively correlates with the proportion of Tc lymphocytes and negatively correlates with the proportion of Th lymphocytes. Our results show that a patient's autoantibody profile reflects the type of cellular immune responses. It seems that the high titre of IA2 autoantibodies is related to increased production of IL17 and an increased proportion of Tc lymphocytes. This finding may be useful in designing immunointervention studies to prevent T1D.

Maternal BMI and HDL as predictors of pregnancy outcome in women with type 1 diabetes.

OBJECTIVE: Diabetes in pregnancy is associated with increased risks of maternal as well as foetal complications. METHODS: Retrospective data on 96 women and their 96 newborns were anonymously statistically analysed to assess pregnancies of type 1 diabetes (T1D) women managed in our hospital in past nine years. The outcomes of the neonates were divided into three categories according to the clinical status, presence of congenital abnormalities and infant's treatment. RESULTS: We found out that the outcome of newborn infants associated with maternal HbA1c before gestation as well as during the whole course of pregnancy (p < 0.02 for all). Surprisingly, neonatal outcome was strongly associated with the maternal BMI (p < 0.05). In our model, a lowering of BMI by one grade led to an 18% increase in the chance that the newborn will have no health problems. We did not observe an important worsening of chronic diabetic complications in mothers; however, regarding maternal clinical status, we found that preeclampsia occurrence was strongly and independently connected to HDL level (p < 0.01). CONCLUSION: Our data demonstrate that lower pregestational BMI could substantially improve T1D mothers' pregnancy outcome. Lower HDL levels in T1D mothers during pregnancy correlate with higher risk of preeclampsia development.

Experience with real time continuous glucose monitoring in stabilising fluctuating glycaemia during intensive care of the preterm infant of a diabetic mother.

OBJECTIVE: The newborns of diabetic mothers suffer from perinatal complications more frequently than the newborns of healthy women. METHODS: We used for 7 days a real time continuous glucose monitoring system (RT-CGMS) to monitor glucose homeostasis and manage glucose administration in a premature newborn of a diabetic mother. RESULTS: The boy was born at 35 + 5 gestational weeks with typical signs of diabetic fetopathy. RT-CGMS revealed 2 late hypoglycaemia episodes on the 2nd and 4th days. The sensor readings correlated well with glycaemia measured in the laboratory (r = 0.908, p = 0.005). To support conclusions of this case report, we attached the data of five other preterm newborns of diabetic mothers who were later successfully treated according to the RT-CGMS data as well. CONCLUSIONS: This approach allows timely response to glycaemia instability and is applicable even in preterm infants.

The effect of diabetes-associated autoantigens on cell processes in human PBMCs and their relevance to autoimmune diabetes development.

Type 1 Diabetes (T1D) is considered to be a T-helper- (Th-) 1 autoimmune disease; however, T1D pathogenesis likely involves many factors, and sufficient tools for autoreactive T cell detection for the study of this disease are currently lacking. In this study, using gene expression microarrays, we analysed the effect of diabetes-associated autoantigens on peripheral blood mononuclear cells (PBMCs) with the purpose of identifying (pre)diabetes-associated cell processes. Twelve patients with recent onset T1D, 18 first-degree relatives of the TD1 patients (DRL; 9/18 autoantibody positive), and 13 healthy controls (DV) were tested. PBMCs from these individuals were stimulated with a cocktail of diabetes-associated autoantigens (proinsulin, IA-2, and GAD65-derived peptides). After 72 hours, gene expression was evaluated by high-density gene microarray. The greatest number of functional differences was observed between relatives and controls (69 pathways), from which 15% of the pathways belonged to "immune response-related" processes. In the T1D versus controls comparison, more pathways (24%) were classified as "immune response-related." Important pathways that were identified using data from the T1D versus controls comparison were pathways involving antigen presentation by MHCII, the activation of Th17 and Th22 responses, and cytoskeleton rearrangement-related processes. Genes involved in Th17 and TGF-beta cascades may represent novel, promising (pre)diabetes biomarkers.

Case report: type 1 diabetes in monozygotic quadruplets.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the lack of insulin due to an autoimmune destruction of pancreatic beta cells. Here, we report a unique case of a family with naturally conceived quadruplets in which T1D was diagnosed in two quadruplets simultaneously. At the same time, the third quadruplet was diagnosed with the pre-diabetic stage. Remarkably, all four quadruplets were positive for anti-islet cell antibodies, GAD65 and IA-A2. Monozygotic status of the quadruplets was confirmed by testing 14 different short tandem repeat polymorphisms. Serological examination confirmed that all quadruplets and their father suffered from a recent enteroviral infection of EV68-71 serotype. To assess the nature of the molecular pathological processes contributing to the development of diabetes, immunocompetent cells isolated from all family members were characterized by gene expression arrays, immune-cell enumerations and cytokine-production assays. The microarray data provided evidence that viral infection, and IL-27 and IL-9 cytokine signalling contributed to the onset of T1D in two of the quadruplets. The propensity of stimulated immunocompetent cells from non-diabetic members of the family to secrete high level of IFN-α further corroborates this conclusion. The number of T regulatory cells as well as plasmacytoid and/or myeloid dendritic cells was found diminished in all family members. Thus, this unique family is a prime example for the support of the so-called 'fertile-field' hypothesis proposing that genetic predisposition to anti-islet autoimmunity is 'fertilized' and precipitated by a viral infection leading to a fully blown T1D.

Is there any relationship between cytokine spectrum of breast milk and occurence of eosinophilic colitis?

AIM: The aim of our study was to analyse cytokine composition of human milk and its relationship to the development of eosinophilic colitis (EC). METHODS: Cytokines were measured by ELISA method in breast milk of 20 mothers of infants who developed EC and 20 controls. RESULTS: We found significantly higher concentrations of interferon-gamma (IFN-gamma) (Th1 cytokine) in breast milk received by EC infants compared to controls (p = 0.0004). In contrary, IL-18 (Th1-inducing cytokine) was significantly higher in breast milk received by healthy infants comparing to EC infants (p = 0.001). Regulatory cytokine transforming growth factor beta1 (TGF-beta1) showed higher concentrations in breast milk received by healthy infants, although the difference from EC group was not significant (p = 0.072). CONCLUSION: The results of our study showed that infants with EC were receiving breast milk with a possibly risky cytokine pattern indicating cytokine imbalance, impaired immunoregulation and the early Th1 shift.