In this study, we analyzed the production of interferon γ (IFN-γ) and interleukin 10 (IL-10) by peripheral blood mononuclear cells (PBMCs) in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the capacity of monocytes to produce tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) following IFN-γ stimulation and the associated role of IL-10 in TNF-α and IL-6 production. Patients and Methods: In vitro experiments were conducted on PBMCs obtained from 19 patients with T2DM and 17 healthy participants. PBMCs were isolated from venous blood by density gradient centrifugation, followed by 3-day phytohemagglutinin induction. In vitro production of TNF-α, IL-6, IFN-γ, and IL-10 was measured using the multiplex immunoassay. Statistical analysis was performed using IBM SPSS 23 version. Results: IFN-γ concentration in the T2DM group was significantly lower than that in control group (T2DM 7,700.86 ± 3,037.77 vs control 10,672.69 ± 5,625.50 pg/mL; p = 0.048). However, TNF-α, IL-6, and IL-10 levels showed no significant difference between the two groups. The TNF-α/IFN-γ and IL-6/IFN-γ ratios were significantly higher in T2DM than in the control group (p = 0.026 and p = 0.048, respectively). In T2DM, the high TNF-α/IFN-γ ratio was consistent, with the low baseline IL-10 level (p = 0.022). Conclusion: In T2DM, T-cell response is impaired with significantly reduced IFN-γ production, and simultaneously, circulatory monocytes show enhanced cellular responsiveness to inflammatory stimuli. The low baseline IL-10 level likely contributes to such an immune response.

Type 2 Diabetes Mellitus (T2DM) is a very serious global problem. In Indonesia, this disease attacks at the most productive age; consequently, it can reduce economic status and life expectancy. The pathogenesis of T2DM is very closely related to inflammation and macrophage accumulation. However, no anti-inflammatory agent has been proven to play a role in the management of T2DM. Butyrate is a short chain fatty acid produced from resistant starch fermentation in the intestinal lumen. It is able to bind to GPR41 and GPR43 receptors on monocytes, so that it can change the pattern of cytokine expression, activation, migration and cell differentiation. Hence, it is interesting to examine the anti-inflammation effect of butyrate and the effect on monocyte migration. A total of 37 subjects were examined in this study. They were divided into two groups, with and without butyrate treatment. We analyzed two pro-inflammatory cytokines (Tumor Necrosis Factor TNF-α and Interleukin IL-6) and one anti-inflammatory cytokine, IL 10. Monocytes were isolated in type 1 collagen gel for migration testing using the µ-slide chemotaxis IBIDI. Image analysis used ImageJ and Chemotaxis tool software. There was a significant difference in the TNFα/IL 10 ratio between healthy groups and T2DM. Butyrate also appears to suppress TNFα cytokine production and increase IL10 production. It also decreases the accumulation distance of monocyte migration in T2DM.

Aim: To analyze indoleamine 2,3-dioxygenase (IDO) production in the cell culture supernatant of phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) from type 2 DM (T2DM) patients and investigate IDO’s association to pro- and anti-inflammatory cytokines. Subjects and methods: PBMC samples were collected from 21 T2DM patients and 17 normoglycemic participants, then stimulated with PHA for 3 days. Cytokine and IDO concentrations were measured in the PBMC culture supernatants. In vitro production of TNF-α, IL-6, interferon-γ, and IL-10 were measured using multiplex immunoassay. IDO concentration was assessed using ELISA. To assess how PHA stimulation altered IDO production and to minimize the unstimulated baseline effect of T2DM, we subtracted the PHA-stimulated IDO concentration from the unstimulated one. IBM SPSS version 23 was used for statistical analysis. Results: The IDO concentrations in the PBMC culture supernatants were significantly higher in T2DM patients regardless of whether they were unstimulated ( P < .001) or PHA-stimulated ( P = .012). Reduced IDO production was observed in 52.8% of T2DM patients and was associated with older age and lower interferon-γ levels. Conversely, 42.8% of T2DM patients showed increased IDO concentrations, which were correlated with the IL-6/IL-10 ratio ( r = 0.683, P = .021) and interferon-γ/IL-10 ratio ( r = 0.517, P = .077). Conclusion: The interferon-γ level was reduced in the PBMC culture supernatant of T2DM patients with reduced IDO production. Reduced IDO production in T2DM patients following PHA stimulation was associated with older age and, notably, higher baseline IDO concentrations. Since IDO is primarily produced by dendritic cells, reduced IDO production after PHA stimulation may indicate dendritic cell dysfunction.

Type 2 diabetes mellitus (T2DM) is associated with chronic low-grade inflammation, which is marked by the dysregulation of innate and adaptive immune responses. Therefore, reducing inflammation, possibly through an immunoregulatory agent, may play a role in T2DM treatment. Butyrate is the most potent short-chain fatty acid (SCFA), and it exerts anti-inflammatory properties by inhibiting histone deacetylase activity. As an immunoregulatory agent, sodium butyrate can inhibit nuclear factor kB (NF-kB) activation and reduce the production of pro-inflammatory cytokines in immune cells. The aim of the study was to measure the level of plasma butyrate in poorly controlled T2DM and normoglycemic participants and to compare the response of peripheral blood mononuclear cells (PBMCs) to sodium butyrate treatment between the groups by measuring production of the following cytokines: tumor necrosis factor (TNF)-α, interleukin (IL)-6, interferon (IFN)-γ, IL-13, and IL-10. The in vitro study examined the PBMCs of 15 participants with poorly controlled T2DM and 15 normoglycemic participants. PBMCs were cultured with the following stimulations for two days at a temperature of 37°C and 5% CO2: 100 ng/mL lipopolysaccharide (LPS), 1 mM sodium butyrate, or a combination of 100 ng/mL LPS and 1 mM sodium butyrate. Plasma butyrate was measured using gas chromatography-mass spectrometry, and cytokines from culture supernatant were analyzed using magnetic beads multiplex assay. Plasma butyrate levels in participants with poorly controlled T2DM did not significantly differ from those in normoglycemic participants (p = 0.105). Compared to treatment with an LPS-stimulated PBMC culture, treatment with 1 mM sodium butyrate reduced the levels of TNF-α (p &lt; 0.039) and IFN-γ (p &lt; 0.038) in normoglycemic participants. The same general trend was seen in PBMC from participants with poorly controlled T2DM, but higher variability appeared to preclude statistical significance. These data suggest that butyrate may modulate inflammatory cytokine production in human PBMCs, but more research is needed to determine if butyrate is anti-inflammatory in poorly controlled T2DM.