Letter to the Editor: Mechanistic insights into tumor necrosis factor-α-mediated islet β-cell apoptosis in acute pancreatitis-associated abnormal glucose metabolism

Abstract

The study by Chen et al, published in the recent issue of the World Journal of Gastroenterology, which systematically elucidate the role of tumor necrosis factor-α (TNF-α) in abnormal glucose metabolism following acute pancreatitis, demonstrating that TNF-α induces islet β-cell apoptosis through activation of the Bax/Bcl-2/caspase-3 pathway. While these findings provide mechanistic insights, the study’s scope remains limited by insufficient investigation into upstream/downstream TNF-α signaling, including the role of TNF receptor subtypes and potential crosstalk with other inflammatory or metabolic pathways. The translational potential of TNF-α inhibition in preventing pancreatitis-associated diabetes is promising, yet clinical application requires careful assessment of potential risks, including increased susceptibility to infection and impaired tissue repair, particularly during the acute inflammatory phase. Further validation in broader populations and longer-term studies is needed to establish safety, efficacy, and optimal timing for such interventions.

Key Words: Acute pancreatitis; Glucose metabolism; Tumor necrosis factor-α; Apoptosis; Islet β-cell; Post-pancreatitis diabetes mellitus; Insulin secretion

Core Tip: Chen et al demonstrate the role of tumor necrosis factor-α (TNF-α) in promoting islet β-cell apoptosis via the Bax/Bcl-2/caspase-3 pathway during acute pancreatitis, which contributes to abnormal glucose metabolism. While acknowledging the therapeutic potential of TNF-α inhibition, the letter highlights limitations such as unexplored upstream signaling and clinical issues, urging future research into broader mechanisms and prospective validations.

TO THE EDITOR

We have read with great interest the article by Chen et al[1], published in the recent issue of the World Journal of Gastroenterology. This study significantly improves our understanding of the metabolic complications following acute pancreatitis (AP), particularly by elucidating the inflammatory mechanisms linking AP to post-pancreatitis diabetes mellitus (PPDM)[2]. We appreciate the opportunity to discuss the findings of this work and, at the same time, address its limitations to guide future investigations into specific mechanisms, such as tumor necrosis factor-α (TNF-α) receptor involvement and crosstalk with other signaling pathways.

Clinical findings and mechanistic validation

The retrospective analysis of 369 AP patients reveals a significant abnormal glucose metabolism (AGM) incidence of 40.38% during hospitalization, consistent with previous epidemiological reports[3]. The multivariate analysis identifying body mass index, AP severity, recurrence frequency, and lung injury as independent risk factors provides insights for clinical risk stratification[4-6]. However, the retrospective design and lack of long-term follow-up data somewhat limit our understanding of the natural progression from AGM to overt diabetes. Prospective studies with extended monitoring are thus needed to clarify the precise timeline and reliable predictors for PPDM development[7,8].

To mechanistically link these clinical observations, the authors used a combination of in vitro and in vivo models. Their experimental results clearly demonstrate a dose-dependent effect of TNF-α on promoting β-cell apoptosis through the Bax/Bcl-2/caspase-3 pathway. A strength of their approach is the use of conditioned medium from lipopolysaccharide-stimulated acinar cells to simulate the paracrine inflammatory microenvironment of AP on β-cells, thus providing a physiologically relevant model. Moreover, the addition of glucose-stimulated insulin secretion assays successfully bridges the observed β-cell apoptosis with functional insulin secretion deficits.

Therapeutic implications and translational potential

The demonstration that TNF-α inhibition attenuates β-cell apoptosis and restores insulin secretion function highlights a promising therapeutic avenue. This approach aligns with growing interest in targeting inflammatory pathways for metabolic disorders, particularly given the clinical availability of TNF-α inhibitors for autoimmune conditions[9-11]. Historically, TNF-α blockade in AP remained largely hypothetical[12] and did not advance into clinical trials due to practical and scientific challenges. However, renewed preclinical and clinical interest (Clinical Trial NCT03684278) has emerged in recent years, supporting the re-evaluation of this strategy[13,14].

However, putting these findings into clinical practice requires a balanced perspective. Potential risks, including increased susceptibility to infection and impaired tissue repair, particularly during acute inflammation, must be carefully evaluated. Moreover, the optimal intervention window, for instance distinguishing early vs late intervention, and the patient subgroups most likely to benefit, such as those defined by AP severity or genetic background, remain to be clearly defined. Future clinical trials should therefore systematically assess safety, efficacy, treatment timing, and patient subgroup classification. Such well-designed studies will provide a more thorough and clinically useful assessment of TNF-α inhibition in this context.

Limitations and future research directions

The study specifically focuses on the TNF-α-mediated Bax/Bcl-2/caspase-3 apoptotic pathway after AP. Although this pathway is clearly involved, the investigation did not explore the upstream regulators of TNF-α expression or the potential distinct roles of TNF-α receptor (TNFR) subtypes (TNFR1/TNFR2), leaving the mechanistic initiation and specificity incompletely defined. Mechanistically, further investigation is required to elucidate the upstream signaling events that drive TNF-α elevation in AP, as well as to determine the specific contributions of TNFR1 and TNFR2 to β-cell apoptosis. We also suggest examining the role of TNFR1/TNFR2 signaling and its potential crosstalk with the nuclear factor kappa-B or mitogen-activated protein kinase pathways in mediating this apoptotic process.

Moreover, while the present work highlights one prominent pathway, a more comprehensive understanding of AP-related diabetes requires comparing this mechanism with other established hypotheses. These include, but are not limited to, post-inflammatory islet fibrosis, alterations in incretin physiology, persistent low-grade inflammation, and dysfunction of the pancreatic endocrine-exocrine axis. It is crucial to explore this broader spectrum of mechanisms, as targeting a single pathway alone may not be sufficient to effectively prevent or ameliorate pancreatogenic diabetes. Consequently, future research should also evaluate the potential of combination therapies that simultaneously target multiple inflammatory and fibrotic pathways, which may yield superior therapeutic benefits.

CONCLUSION

In conclusion, Chen et al[1] study offers insights into β-cell apoptosis driven by TNF-α as a key factor of AGM after AP, with promising implications for clinical targeting. However, the limited exploration of upstream pathways and the absence of long-term follow-up underscore the need for prospective studies. We encourage continued research into inflammatory pathways in pancreatogenic diabetes to improve both basic science and clinical applications.