[Application of the Chinese Expert Consensus on Diabetes Classification in clinical practice]

Objective: To evaluate the diagnostic for classification of newly diagnosed diabetes patients and assess the application of the screening tests recommended by the 2022 Chinese Expert Consensus on Diabetes Classification. Methods: Retrospective case series study. The data from the electronic medical record system of patients with new-onset diabetes mellitus (within 1 year of disease onset) who attending the Diabetes Specialist Outpatient Clinic at the Second Xiangya Hospital of Central South University from January 1, 2018 to December 31, 2021 were collected for the analysis. Based on the consensus, patients were categorized according their age of onset, body mass index (BMI), and suspicion of type 1 diabetes mellitus (T1DM). The chi-square statistic was used to compare key classifier indicators, including C-peptide, islet autoantibodies, and genetic markers, in the subgroups. The diagnosis in suspected T1DM patients was also evaluated. The screening strategy recommended in the consensus was further assessed using a logistic regression model and the area under the receiver-operating curve (AUC). Results: A total of 3 384 patients with new-onset diabetes were included. The average age of disease onset was (46.3±13.9) years, and 61.0% (2 065/3 384) of the patients were male. The proportions of patients who completed C-peptide and glutamic acid decarboxylase antibody (GADA) tests were 36.6% (1 238/3 384) and 37.5% (1 269/3 384), respectively. There were no significant differences in C-peptide test results among the subgroups (all P>0.05). In contrast, the GADA detection rate was higher in patients with young age of onset (<30 years old), in those who were non-obese (BMI<24 kg/m2), and in those clinically suspected of T1DM (all P<0.05). According to the diagnostic pathway proposed by the consensus, only 57.4% (1 941/3 384) of patients could be subtyped. For a definitive diagnosis, the remaining patients needed completion of C-peptide, islet autoantibody, genetic testing, or follow-up. Furthermore, among patients with clinical features of suspected T1DM, the antibody positivity rate was higher than in non-suspected T1DM patients [24.5% (154/628) vs. 7.1% (46/646), P<0.001]. When the clinical features of suspected T1DM defined in the consensus were taken as independent variables and antibody positivity was considered the outcome variable in the logistic regression model, young onset, non-obese onset, and ketosis onset could enter the model. Based on AUC analysis, the accuracy of the diagnostic model was 0.77 (95%CI 0.73-0.81), suggesting that the clinical features of suspected T1DM in the consensus have good clinical diagnostic value for this patient subgroup. Conclusions: There was a significant discrepancy between the clinical practice of diabetes classification and the process recommended by the consensus, which was specifically reflected in the low proportions of both subtyping indicator testing and definitively subtyped diabetes patients. Attention should be pay to the classification diagnosis process proposed in the consensus and the clinical detection rate of key diabetes subtyping indicators such as C-peptide and islet autoantibodies for diabetes classification should be improved. Noteworthy, the screening strategy for T1DM proposed by the consensus showed good clinical application value.

[The relation between residual β-cell function and autoimmune status in long-term type 1 diabetes patients]

Objective: We aimed to investigate the autoimmune status of long-term type 1 diabetes mellitus (T1DM) patients with residual β-cell function. Methods: The residual β-cell function of long-term (disease duration≥10 years) autoimmune T1DM patients from the T1DM Integrated Management Clinic of the Second Xiangya Hospital was assessed by serum C-peptide levels. Patients with fasting or 2-hour postprandial C-peptide levels over the lower sensitivity limit of detection (16.7 pmol/L) were grouped as C-peptide-positive, and others were grouped as C-peptide-negative. We screened and enrolled all the C-peptide-positive patients (n=19). C-peptide-negative patients with matched sex, age, duration, BMI (n=19) and healthy controls (n=19) were recruited at the same time. The frequencies of CD4+T cell (Th1/Th2/Th17/Treg) and B cell (MZB/FoB/B10) subsets, the expression of PD-1/PD-L1 on T and B lymphocytes, and the levels of T1DM related cytokines including IFN-γ, TNF-α, IL-1β, IL-1RA, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, IL-23 and IP-10 were tested. We compared these parameters in patients with different levels of β-cell function. Results: In healthy controls, C-peptide-negative and C-peptide-positive patients, the frequencies M (Q₁, Q₃) of Th1 cells were 9.93% (7.45%, 15.20%), 14.90% (11.70%, 18.00%) and 10.20% (6.93%, 15.80%) (P=0.015), and the frequencies M (Q₁, Q₃) of Treg cells were 3.52% (2.92%, 5.68%),2.88% (1.64%, 3.22%) and 3.12% (2.81%, 4.81%) (P=0.005), and the frequencies M(Q₁,Q₃) of PD-1+B cells were 4.69% (2.64%, 6.37%), 2.11% (1.45%, 3.63%) and 4.20% (2.53%, 6.01%) (P=0.003), respectively. The levels of IL-6 M(Q₁,Q₃)were 26.43(18.06, 33.35) ng/L, 42.97 (25.52, 66.30) ng/L, and 22.07 (14.85, 34.45) ng/L (P=0.006), and the levels of IP-10 M(Q₁,Q₃) were 107.39 (76.19, 126.07) ng/L, 188.82 (131.27, 348.18) ng/L and 128.26 (114.31, 136.50) ng/L (P<0.001) in healthy controls, C-peptide-negative and C-peptide-positive patients, respectively. Compared with C-peptide-positive patients, the frequency of Th1 cells and the levels of IL-6 and IP-10 cytokines were higher, while the frequencies of Treg cells and PD-1+B cells were lower in C-peptide-negative patients (all P<0.05). Conclusions: Long-term T1DM patients with residual β-cell function had lower frequency of Th1 cells, lower levels of IL-6, IP-10 cytokines, and higher frequencies of Treg and PD-1+B cells, which indicated a pronounced autoimmune tolerance.

High dislocation density-induced large ductility in deformed and partitioned steels

A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

Serial experimental and clinical studies on the pathogenesis of multiple organ dysfunction syndrome (MODS) in severe burns

These serial clinical and experimental studies were designed to clarify the pathogenesis of postburn MODS. Both animal and clinical studies were performed. In animal experiments, 46 male cross-bred dogs were cannulated with Swan-Ganz catheters and 39 of them were inflicted with 50% TBSA third degree burns (7 were used as controls). The burned dogs were randomly divided into 4 groups: immediate infusion, delayed infusion, delayed fast infusion and delayed fast infusion combined with ginsenosides. All dogs were kept under constant barbiturate sedation during the whole study period. Hemodynamics, visceral MDA, mitochondrial respiratory control rate (RCR) and ADP/O ratio, ATP, succinic dehydrogenase (SDH), organ water content as well as light and electron microscopy of visceral tissues were determined. In the clinical study, 61 patients with extensive deep burns were chosen, of which 16 sustained MODS. Plasma TXB2/6-keto-PGF1alpha ratio, TNF, SOD, MDA, circulatory platelet aggregate ratio (CPAR), PGE2, interleukin-1, total organ water content and pathological observations of visceral tissues from patients who died of MODS were carried out. Results demonstrated that ischemic-reperfusion damage due to severe shock, sepsis and inhalation injury are three main causes of postburn death. All inflammatory mediators increased markedly in both animals and patients who sustained organ damage or MODS. SDH, RCR, ADP/O and ATP decreased significantly. These findings suggested that ischemic damage and systemic inflammatory response syndrome (SIRS) initiated by mediators or cytokines might be important in the pathogenesis of postburn MODS.

Blood gas studies in dogs with severe steam inhalation injury

The dynamic changes in blood gases in 34 dogs suffering severe steam inhalation injury were studied during the first 14 days post-burn to determine the effects of inhalation injury on lung function. Nineteen dogs received only severe steam inhalation injury, while 15 other dogs received both 30 per cent total body surface area (TBSA) deep burns and steam inhalation injury. The results showed marked reductions of PaO2, PaCO2, AB, SBE, T-CO2, SB, BBp, pHNR and SatO2 (P less than 0.05 approximately 0.01), whereas the P(A-a)O2 increased (P less than 0.05 approximately 0.01) within week 1 post-burn in both groups. These data suggest that the injured animals were suffering from hypoxaemia and respiratory alkalosis induced by disturbance of the gas-exchange function of the lungs. There was also metabolic acidosis, which was closely related to high fever, excessive catabolism, and particularly to hypoxaemia in week 1 post-burn. If the animals survived through the critical period (1-7 days post-burn), most of the abnormal gas parameters then gradually returned to the pre-burn levels. It is clear, therefore, that blood gas monitoring in patients with inhalation injury is not only of diagnostic importance but also of prognostic value.