The etiology and pathogenesis of type 1 diabetes - A personal, non-systematic review of possible causes, and interventions

Advances in the Pathogenesis and Treatment Strategies for Type 1 Diabetes Mellitus

Type 1 diabetes (T1D) is a complex autoimmune disorder distinguished by the infiltration of immune cells into pancreatic islets, primarily resulting in damage to pancreatic β-cells. Despite extensive research, the precise pathogenesis of T1D remains elusive, with its etiology linked to a complex interplay of genetic, immune, and environmental factors. While genetic predispositions, such as HLA and other susceptibility genes, are necessary, they do not fully account for disease development. Environmental influences such as viral infections and dietary factors may contribute to the disease by affecting the immune system and epigenetic modifications. Additionally, endogenous retroviruses (ERVs) might play a role in T1D pathogenesis. Current therapeutic approaches, including insulin replacement therapy, immune omodulatory therapy, autoantigen immunotherapy, organ transplantation, and genetic modification, offer potential to alter disease progression but are still constrained by limitations. This review presents updated knowledge on T1D, with a focus on risk factors, predisposing hypotheses, and recent advancements in therapeutic strategies.

Comparison of pediatric diabetic ketoacidosis in newly diagnosed versus known patients with type 1 diabetes mellitus: A single-center study

OBJECTIVES

To compare the demographic, clinical, and biochemical characteristics of newly diagnosed versus known patients with type 1 diabetes mellitus (T1DM) presenting with diabetic ketoacidosis (DKA) in a tertiary care center in the Western region of Saudi Arabia.

METHODS

We retrospectively reviewed 147 children and adolescents diagnosed with T1DM who presented with DKAs between January 2019 and December 2023. Data on age, gender, nationality, economic status, episode severity, presenting symptoms, and biochemical markers were collected and analyzed.

RESULTS

The mean patient age was 7.24 years, with known patients being older (mean age: 8.24 years) than newly diagnosed patients (mean age: 6.34 years). Most patients (55.8%) belonged to the middle-childhood age group (6 to 11 years). Among known patients, the most prevalent symptoms included vomiting, reported by 62 (88.6%) individuals, and abdominal pain, which affected 55 (78.6%). In contrast, new patients exhibited a strikingly high incidence of polyuria, with 68 (88.3%) cases, and polydipsia, affecting 65 (84.4%) individuals.

CONCLUSION

The DKA incidence was higher in newly diagnosed patients, particularly in the middle-childhood age group. Economic factors may contribute to disease manifestations, and newly diagnosed patients had longer DKA symptom durations. The higher DKA incidence and severity in newly diagnosed patients, particularly in certain age groups, underscores the importance of increased disease awareness and early diagnosis.

Early Onset of Type 1 Diabetes in Kuwait: Distinct Clinical, Metabolic, and Immunological Characteristics

OBJECTIVE

Exploring early-onset diabetes in terms of describing characteristics at time of diagnosis might aid in a better understanding of etiology and may have implications on management and prevention. The aim of this study was to investigate the prevalence of early-onset type 1 diabetes (T1D) in Kuwait as well as describe their baseline clinical, biochemical, and immunological characteristics.

METHODS

Medical records of children newly diagnosed with T1D and registered in the Childhood-Onset Diabetes electronic Registry (CODeR) in Kuwait between 2017 and 2022 were reviewed. Early-onset T1D was defined as diagnosis at age younger than 6 years.

RESULTS

2,051 children were registered with new-onset T1D between 2017 and 2022, of which 657 (32.0%) were diagnosed at early onset. There has been a trend of slight increase in the percentage of early-onset T1D after 2020 (15.2%) with a prevalence of 18.4% and 20.2% in 2021 and 2022, respectively (p = 0.056). Age at onset was inversely related to admission to the pediatric intensive care unit (OR = 0.90, 95% CI: 0.85, 0.95, p < 0.0001) and was directly related to positive celiac autoimmunity (p = 0.022), higher hemoglobin A1C (p < 0.0001), and C-peptide levels (p < 0.0001). However, age at onset of T1D was inversely related to the higher vitamin D levels (p < 0.0001).

CONCLUSION

These findings reinforce the need for increased attention to be given to study the development of T1D in children of younger age. This in turn will support special management and prevention measures targeted toward this vulnerable age group.

Applications of Genome-Editing Technologies for Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by the destruction of insulin-producing pancreatic β-cells by the immune system. Although conventional therapeutic modalities, such as insulin injection, remain a mainstay, recent years have witnessed the emergence of novel treatment approaches encompassing immunomodulatory therapies, such as stem cell and β-cell transplantation, along with revolutionary gene-editing techniques. Notably, recent research endeavors have enabled the reshaping of the T-cell repertoire, leading to the prevention of T1D development. Furthermore, CRISPR-Cas9 technology has demonstrated remarkable potential in targeting endogenous gene activation, ushering in a promising avenue for the precise guidance of mesenchymal stem cells (MSCs) toward differentiation into insulin-producing cells. This innovative approach holds substantial promise for the treatment of T1D. In this review, we focus on studies that have developed T1D models and treatments using gene-editing systems.

Challenges and opportunities in the islet transplantation microenvironment: a comprehensive summary of inflammatory cytokine, immune cells, and vascular endothelial cells

It is now understood that islet transplantation serves as a β-cell replacement therapy for type 1 diabetes. Many factors impact the survival of transplanted islets, especially those related to the microenvironment. This review explored microenvironmental components, including vascular endothelial cells, inflammatory cytokines, and immune cells, and their profound effects on post-islet transplantation survival rates. Furthermore, it revealed therapeutic strategies aimed at targeting these elements. Current evidence suggests that vascular endothelial cells are pivotal in facilitating vascularization and nutrient supply and establishing a new microcirculation network for transplanted islets. Consequently, preserving the functionality of vascular endothelial cells emerges as a crucial strategy to enhance the survival of islet transplantation. Release of cytokines will lead to activation of immune cells and production and release of further cytokines. While immune cells hold undeniable significance in regulating immune responses, their activation can result in rejection reactions. Thus, establishing immunological tolerance within the recipient's body is essential for sustaining graft functionality. Indeed, future research endeavors should be directed toward developing precise strategies for modulating the microenvironment to achieve higher survival rates and more sustained transplantation outcomes. While acknowledging certain limitations inherent to this review, it provides valuable insights that can guide further exploration in the field of islet transplantation. In conclusion, the microenvironment plays a paramount role in islet transplantation. Importantly, we discuss novel perspectives that could lead to broader clinical applications and improved patient outcomes in islet transplantation.

SARS-CoV-2 Positive Serology and Islet Autoantibodies in Newly Diagnosed Pediatric Cases of Type 1 Diabetes Mellitus: A Single-Center Cohort Study

Acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, although presenting less severe forms of the disease in children, seems to play a role in the development of other conditions, including type 1 diabetes mellitus (T1DM). After the beginning of the pandemic, an increase in the number of T1DM pediatric patients was observed in several countries, thus leading to many questions about the complex relationship between SARS-CoV-2 infection and T1DM. Our study aimed to highlight possible correlations between SARS-CoV-2 serology and T1DM onset. Therefore, we performed an observational retrospective cohort study that included 158 children diagnosed with T1DM in the period April 2021-April 2022. The presence or absence of SARS-CoV-2 and T1DM-specific antibodies and other laboratory findings were assessed. In the group of patients with positive SARS-CoV-2 serology, a higher percentage had detectable IA-2A antibodies, more children were positive for all three islet autoantibodies determined (GADA, ICA, and IA-2A), and a higher mean HbA1c value was found. No difference existed between the two groups regarding DKA presence and severity. A lower C-peptide level was found in the patients presenting diabetic ketoacidosis (DKA) at T1DM onset. When compared to a group of patients diagnosed before the pandemic, an increased incidence of both DKA and severe DKA, as well as a higher age at diagnosis and higher levels of HbA1c were present in our study group. These findings have important implications for the ongoing monitoring and management of children with T1DM after the COVID-19 pandemic and highlight the need for further research to better understand the complex relationship between SARS-CoV-2 infection and T1DM.

Clostridia and Enteroviruses as Synergistic Triggers of Type 1 Diabetes Mellitus

What triggers type 1 diabetes mellitus (T1DM)? One common assumption is that triggers are individual microbes that mimic autoantibody targets such as insulin (INS). However, most microbes highly associated with T1DM pathogenesis, such as coxsackieviruses (COX), lack INS mimicry and have failed to induce T1DM in animal models. Using proteomic similarity search techniques, we found that COX actually mimicked the INS receptor (INSR). Clostridia were the best mimics of INS. Clostridia antibodies cross-reacted with INS in ELISA experiments, confirming mimicry. COX antibodies cross-reacted with INSR. Clostridia antibodies further bound to COX antibodies as idiotype-anti-idiotype pairs conserving INS-INSR complementarity. Ultraviolet spectrometry studies demonstrated that INS-like Clostridia peptides bound to INSR-like COX peptides. These complementary peptides were also recognized as antigens by T cell receptor sequences derived from T1DM patients. Finally, most sera from T1DM patients bound strongly to inactivated Clostridium sporogenes, while most sera from healthy individuals did not; T1DM sera also exhibited evidence of anti-idiotype antibodies against idiotypic INS, glutamic acid decarboxylase, and protein tyrosine phosphatase non-receptor (islet antigen-2) antibodies. These results suggest that T1DM is triggered by combined enterovirus-Clostridium (and possibly combined Epstein-Barr-virus-Streptococcal) infections, and the probable rate of such co-infections approximates the rate of new T1DM diagnoses.