Letter to the Editor: Tumor necrosis factor-α signaling and β-cell apoptosis in acute pancreatitis - integrating molecular mechanisms and metabolic implications

Abstract

The recent study by Chen et al, published in the World Journal of Gastroenterology, provides valuable evidence that tumor necrosis factor-α (TNF-α) contributes to acute metabolic disorder after acute pancreatitis through Bax/Bcl-2-mediated β-cell apoptosis. Their study elegantly combines clinical observations with experimental data, but the biological framework underlying TNF-α signaling in β-cell damage is more complex than a single apoptotic pathway. TNF-α appears to function as a central hub, linking nuclear factor kappa B (NF-κB) activation, oxidative and endoplasmic reticulum stress, and cytokine cross-talk, all of which influence β-cell survival. The apoptotic cascade described by Chen et al can be viewed as one effector branch of this wider network. Moreover, TNF-α affects key metabolic aspects of β-cell function, including mitochondrial activity and GLUT2-dependent glucose handling, suggesting that metabolic dysfunction and apoptosis may arise together as part of an integrated stress response. By briefly outlining these additional mechanisms, this article places TNF-α within a broader inflammatory-metabolic context that complements and extends their interpretation.

Key Words: Tumor necrosis factor-α; β-cell apoptosis; Oxidative stress; Endoplasmic reticulum stress; Glucose metabolism; Acute pancreatitis; Post-pancreatitis diabetes mellitus; Inflammatory signaling

Core Tip: Tumor necrosis factor-α (TNF-α) contributes to dysglycemia after acute pancreatitis not only by activating apoptotic pathways, but also by coordinating a broader network of inflammatory, oxidative, endoplasmic reticulum stress, and metabolic signals that impair β-cell function. Recognizing TNF-α as an upstream integrator, rather than a single apoptotic trigger, helps explain the heterogeneity of post-pancreatitis dysglycemia and highlights new therapeutic opportunities aimed at enhancing β-cell metabolic resilience.

TO THE EDITOR

Understanding how inflammatory mediators contribute to post-acute pancreatitis (AP) disturbances in glucose regulation is a rapidly evolving area. This article seeks to place recent mechanistic findings in a broader context, proposing that tumor necrosis factor-α (TNF-α) should be viewed not merely as an apoptotic trigger, but as an upstream coordinator within a wider network of interdependent β-cell stress pathways, with relevant implications for the heterogeneity of post-pancreatitis diabetes mellitus (PPDM). In this context, the recent study by Chen et al[1] published in the World Journal of Gastroenterology provides valuable mechanistic evidence that TNF-α promotes abnormal glucose metabolism by activating the Bax/Bcl-2/caspase-3 apoptotic pathway in pancreatic β-cells. Their work, combining clinical observations with in vitro and in vivo models, adds an important piece to the understanding of the pathophysiology of post-pancreatitis dysglycemia. As acknowledged by the authors themselves, their experiments did not explore upstream TNF receptor signaling or the interplay between nuclear factor kappa B (NF-κB)/mitogen-activated protein kinases (MAPK) and apoptotic pathways, indicating that additional components of TNF-α-driven β-cell stress remain to be elucidated. When positioned within the broader body of β-cell biology and inflammation research, their findings suggest a more complex picture in which TNF-α acts not as a single pro-apoptotic insult but as an upstream coordinator of multiple stress pathways. This broader perspective may help frame their results within current concepts regarding PPDM, an increasingly recognized clinical entity characterized by heterogeneous mechanisms and often distinct from type 2 diabetes[2-5].

TNF-α AS AN UPSTREAM HUB OF INTEGRATED β-CELL STRESS SIGNALING

In the context of the mechanisms discussed by Chen et al[1], pro-inflammatory cytokines, including TNF-α, IL-1β, and IFN-γ, are known to activate interconnected networks that impair β-cell function and viability. Rather than acting through isolated pathways, cytokine signaling triggers NF-κB activation, MAPK pathways, oxidative stress, and endoplasmic reticulum (ER) stress, as described by Eizirik et al[4].

Importantly, these processes are tightly interconnected: ER stress can exacerbate oxidative stress, mitochondrial dysfunction amplifies apoptotic susceptibility, and oxidative-inflammatory interactions can reinforce β-cell stress signaling[4,6,7]. In this context, mitochondrial dysfunction, including loss of mitochondrial membrane potential (ΔΨm), further amplifies β-cell susceptibility to apoptotic signaling. Within this framework, the apoptotic cascade identified by Chen et al[1], although central, can be interpreted as one effector branch of a broader integrated stress response. Studies by Maestre et al[8] and Gurzov et al[9] show that cytokine- and metabolite-induced β-cell injury often arises from the convergence of mitochondrial impairment, reactive oxygen species accumulation, impaired calcium handling and synergistic cytokine signaling. This integrated view supports the positioning of TNF-α upstream, as an amplifier of multiple stress signals rather than as a single pro-apoptotic trigger.

Together, these established mechanisms provide a broader context in which the findings of Chen et al[1] can be interpreted.

METABOLIC DYSFUNCTION AS A PARALLEL CONTRIBUTOR TO POST-AP DYSGLYCEMIA

In addition to apoptosis, Chen et al[1] demonstrate that higher TNF-α levels correlate with impaired insulin secretion and that TNF-α inhibition partially restores β-cell function. This aligns with extensive evidence that inflammation disrupts core metabolic processes required for glucose-stimulated insulin secretion. Consistent with the functional alterations reported by Chen et al[1], β-cell glucose sensing relies on GLUT2-mediated glucose uptake and mitochondrial ATP generation. Thorens[10] established the essential role of GLUT2 in glucose-stimulated insulin secretion, while oxidative stress-driven mitochondrial dysfunction can impair the tight coupling between glucose sensing and insulin exocytosis[6,8,9]. Dinić et al[6] and Eguchi et al[5] further highlight how redox imbalance compromises ATP production and overall β-cell metabolic resilience. These findings support the notion that, during AP-related inflammation, β-cell metabolic dysfunction and apoptosis may develop in parallel. Clinical data reinforce this interpretation: PPDM can occur even in the absence of extensive necrosis, suggesting that functional impairment of surviving β-cells is an important component of early dysglycemia[2-5].

β-CELL IDENTITY ALTERATIONS: AN ADDITIONAL MECHANISM TO CONSIDER

A growing body of evidence indicates that prolonged oxidative and ER stress may induce loss of β-cell identity, characterized by transcriptional instability and dedifferentiation, compromising insulin secretion even in viable cells[7,11,12]. This phenomenon may help explain the variability and partial reversibility of post-AP glucose dysregulation reported in recent clinical studies[2-5]. Although the study by Chen et al[1] was not designed to assess β-cell identity, incorporating this possibility into the mechanistic framework provides a more nuanced view of how inflammation affects endocrine function beyond apoptosis alone.

THERAPEUTIC IMPLICATIONS: COMBINING APOPTOSIS-TARGETED AND METABOLISM-TARGETED STRATEGIES

The protective effect of pharmacologic TNF-α inhibition observed by Chen et al[1] is biologically plausible and consistent with the central role of TNF-α in coordinating β-cell stress. However, given the pleiotropic roles of TNF-α in host defense and tissue repair, systemic blockade may not always be feasible. Within this conceptual framework, the notion that cellular metabolic vulnerability is closely associated with increased susceptibility to inflammatory injury has been highlighted in the context of metabolic rewiring in hepatocellular carcinoma[13]. Together, these observations support a generalizable principle whereby impaired metabolic adaptability sensitizes cells to inflammatory and oxidative stress, a concept that can reasonably be extended to β-cells exposed to AP-related inflammation. In addition, AP itself is now recognized as a disease of organelle stress, in which early dysfunction of the ER, mitochondria, and autophagy-lysosomal systems initiates local and systemic inflammatory responses[14].

Integrating this perspective with the data by Chen et al[1] supports the view that TNF-α-driven apoptosis occurs against the background of pre-existing organelle and metabolic stress in β-cells (Figure 1).

Figure 1 Integrated model of tumor necrosis factor-α-mediated β-cell stress during acute pancreatitis. Acute pancreatitis induces a strong inflammatory milieu that triggers a surge of tumor necrosis factor-α (TNF-α) released from acinar and infiltrating immune cells. TNF-α activates several convergent β-cell stress pathways, including nuclear factor kappa B, JNK and p38 mitogen-activated protein kinase signaling; accumulation of reactive oxygen species and mitochondrial inefficiency; maladaptive endoplasmic reticulum stress and activation of the unfolded protein response (UPR), with induction of C/EBP homologous protein, a key pro-apoptotic UPR effector; and loss of mitochondrial membrane potential (ΔΨm), increasing susceptibility to cytochrome-c-dependent apoptosis. Together, these pathways amplify Bax upregulation, Bcl-2 downregulation and caspase-3 activation, ultimately driving β-cell apoptosis. These processes impair insulin secretion, contribute to abnormal glucose metabolism, and increase the risk of post-pancreatitis diabetes mellitus. The figure illustrates the proposed “upstream hub” model, in which TNF-α integrates multiple convergent stress signals rather than acting as a single downstream effector. AGM: Abnormal glucose metabolism; GSIS: Glucose-stimulated insulin secretion; PPDM: Post-pancreatitis diabetes mellitus; NF-κB: Nuclear factor kappa B; MAPK: Mitogen-activated protein kinases.

CONCLUSION

The study by Chen et al[1] provides compelling evidence that TNF-α contributes to dysglycemia after AP by activating a key apoptotic pathway. By integrating their results with contemporary knowledge of β-cell inflammatory, metabolic and identity-related stress responses, this article proposes a more integrated mechanistic framework. Recognizing TNF-α as an upstream organizer of multiple convergent stress pathways may better explain the clinical spectrum of PPDM and identify new therapeutic opportunities aimed not only at blocking apoptosis but also at reinforcing β-cell functional resilience. Future studies aimed at dissecting how inflammatory signaling intersects with β-cell metabolic resilience may help identify targeted interventions capable of preserving endocrine function after acute pancreatitis, beyond apoptosis-centered strategies alone.