Single-cell and spatial omics: exploring hypothalamic heterogeneity

Elucidating the complex dynamic cellular organization in the hypothalamus is critical for understanding its role in coordinating fundamental body functions. Over the past decade, single-cell and spatial omics technologies have significantly evolved, overcoming initial technical challenges in capturing and analyzing individual cells. These high-throughput omics technologies now offer a remarkable opportunity to comprehend the complex spatiotemporal patterns of transcriptional diversity and cell-type characteristics across the entire hypothalamus. Current single-cell and single-nucleus RNA sequencing methods comprehensively quantify gene expression by exploring distinct phenotypes across various subregions of the hypothalamus. However, single-cell/single-nucleus RNA sequencing requires isolating the cell/nuclei from the tissue, potentially resulting in the loss of spatial information concerning neuronal networks. Spatial transcriptomics methods, by bypassing the cell dissociation, can elucidate the intricate spatial organization of neural networks through their imaging and sequencing technologies. In this review, we highlight the applicative value of single-cell and spatial transcriptomics in exploring the complex molecular-genetic diversity of hypothalamic cell types, driven by recent high-throughput achievements.

Use of a long-term continuous glucose monitor for predicting sulfonylurea dose in patients with neonatal diabetes mellitus: a case series

Neonatal diabetes mellitus (NDM) is a monogenic form of diabetes that presents with uncontrolled hyperglycemia during the first 6 months of life. NDM is a rare disease in which gene variants mainly cause β-cell loss or dysfunction (6q24 duplication, KCNJ11, and ABCC8). Although NDM is primarily treated through insulin therapy, it is highly challenging to manage blood glucose levels using insulin therapy during infancy. In contrast, KCNJ11 and ABCC8 mutant patients received oral sulfonylureas (SU) instead of insulin injections; however, the dose and frequency differ among individuals. Continuous glucose monitoring (CGM) is useful in patients with type 1 diabetes; but reports on patients with NDM are lacking. Herein, we report two cases of NDM with the KCNJ11 variant. We used CGM not only during insulin injection therapy but also after switching to oral SU therapy. The CGM data can also be used to determine the dose and frequency of SU. Furthermore, long-term CGM may be useful for adjusting SU dose and frequency, and maintaining good glycemic control not only during insulin injection but also during oral SU therapy.

Role of copper chelating agents: between old applications and new perspectives in neuroscience

The role of copper element has been an increasingly relevant topic in recent years in the fields of human and animal health, for both the study of new drugs and innovative food and feed supplements. This metal plays an important role in the central nervous system, where it is associated with glutamatergic signaling, and it is widely involved in inflammatory processes. Thus, diseases involving copper (II) dyshomeostasis often have neurological symptoms, as exemplified by Alzheimer's and other diseases (such as Parkinson's and Wilson's diseases). Moreover, imbalanced copper ion concentrations have also been associated with diabetes and certain types of cancer, including glioma. In this paper, we propose a comprehensive overview of recent results that show the importance of these metal ions in several pathologies, mainly Alzheimer's disease, through the lens of the development and use of copper chelators as research compounds and potential therapeutics if included in multi-target hybrid drugs. Seeing how copper homeostasis is important for the well-being of animals as well as humans, we shortly describe the state of the art regarding the effects of copper and its chelators in agriculture, livestock rearing, and aquaculture, as ingredients for the formulation of feed supplements as well as to prevent the effects of pollution on animal productions.

Context-dependent role of sirtuin 2 in inflammation

Sirtuin 2 is a member of the sirtuin family nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases, known for its regulatory role in different processes, including inflammation. In this context, sirtuin 2 has been involved in the modulation of key inflammatory signaling pathways and transcription factors by deacetylating specific targets, such as nuclear factor κB and nucleotide-binding oligomerization domain-leucine-rich-repeat and pyrin domain-containing protein 3 (NLRP3). However, whether sirtuin 2-mediated pathways induce a pro- or an anti-inflammatory response remains controversial. Sirtuin 2 has been implicated in promoting inflammation in conditions such as asthma and neurodegenerative diseases, suggesting that its inhibition in these conditions could be a potential therapeutic strategy. Conversely, arthritis and type 2 diabetes mellitus studies suggest that sirtuin 2 is essential at the peripheral level and, thus, its inhibition in these pathologies would not be recommended. Overall, the precise role of sirtuin 2 in inflammation appears to be context-dependent, and further investigation is needed to determine the specific molecular mechanisms and downstream targets through which sirtuin 2 influences inflammatory processes in various tissues and pathological conditions. The present review explores the involvement of sirtuin 2 in the inflammation associated with different pathologies to elucidate whether its pharmacological modulation could serve as an effective strategy for treating this prevalent symptom across various diseases.

Assessing the potential fasting and postprandial mechanisms involved in the acute hypoglycemic and anti-hyperglycemic effects of four selected plants from Iran used in traditional Persian medicine

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Persian medicine (TPM), people often use herbal infusions as a dosage form to treat diseases related to hyperglycemia, known as 'dam-kardeh'. Traditionally, herbal preparations of Eryngium bungei Boiss. (E. b), Tragopogon buphthalmoides (DC.) Boiss. (T. b), Salvia hydrangea DC. ex Benth. (S. h), and Juniperus polycarpos K. Koch. (J. p) are used to manage diabetes in Iran. However, there is no evidence of their effectiveness in controlling glucose levels and their mechanisms remain unclear.

AIM OF THE STUDY

This study aimed to investigate whether traditional doses of plant infusions can have hypoglycemic and/or anti-hyperglycemic effects during fasting and/or postprandial states and establish the basis for future research on their potential mechanisms of action.

MATERIALS AND METHODS

The effects of traditional doses of herbal extracts on blood glucose levels in STZ-NA-induced hyperglycemic rats were investigated in 2-h acute tests during fasting and postprandial states (with a glucose load). In addition, the potential inhibitory effect in vitro of enzymes involved in relevant pathways, such as gluconeogenesis (fructose-1,6-bisphosphatase, FBPase and glucose-6-phosphatase, G6Pase), carbohydrate breakdown (intestinal α-glucosidases), and insulin sensitivity (protein tyrosine phosphatase 1B, PTP-1B) was evaluated. Acute toxicity tests were carried out and HPLC-SQ-TOF was used to analyze the chemical profiles of the plant extracts.

RESULTS

In the fasting state, T. b, S. h, and E. b were as effective as glibenclamide in lowering blood glucose levels in hyperglycemic rats. Moreover, all three suppressed G6Pase and FBPase enzymatic activity by 90-97% and 80-91%, respectively. On the other hand, significant postprandial hypoglycemic efficacy was observed for E. b, S. h, and T. b. Based on the AUC values, T. b caused a reduction comparable to the therapeutic efficacy of repaglinide. When investigating the possible mechanisms of action involved in this activity, E. b, S. h, and T. b showed significant inhibition of PTP-1B in vitro (>70%). Finally, all plant extracts showed no signs of acute toxicity. Several compounds that may contribute to biological activities were identified, including phenolic acids and flavonoid glycosides.

CONCLUSIONS

The present study supports the traditional use of T. b, E. b and S. h for the control of diabetes in the fasting and postprandial state. Moreover, these plants were found to be rich in bioactive compounds with hypoglycemic and antihyperglycemic activities. On the other hand, J. p, showed a modest effect only in the fasting state and after 90 min. Further studies are needed to expand these results by analyzing the chemical composition and using complementary experimental models.

Identification of Senkyunolide I as a novel modulator of hepatic steatosis and PPARα signaling in zebrafish and hamster models

ETHNOPHARMACOLOGICAL RELEVANCE

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver-related morbidity and mortality, with hepatic steatosis being the hallmark symptom. Salvia miltiorrhiza Bunge (Smil, Dan-Shen) and Ligusticum striatum DC (Lstr, Chuan-Xiong) are commonly used to treat cardiovascular diseases and have the potential to regulate lipid metabolism. However, whether Smil/Lstr combo can be used to treat NAFLD and the mechanisms underlying its lipid-regulating properties remain unclear.

PURPOSE

To assess the feasibility and reliability of a short-term high-fat diet (HFD) induced zebrafish model for evaluating hepatic steatosis phenotype and to investigate the liver lipid-lowering effects of Smil/Lstr, as well as its active components.

METHODS

The phenotypic alterations of liver and multiple other organ systems were examined in the HFD zebrafish model using fluorescence imaging and histochemistry. The liver-specific lipid-lowering effects of Smil/Lstr combo were evaluated endogenously. The active molecules and functional mechanisms were further explored in zebrafish, human hepatocytes, and hamster models.

RESULTS

In 5-day HFD zebrafish, significant lipid accumulation was detected in the blood vessels and the liver, as evidenced by increased staining with Oil Red O and fluorescent lipid probes. Hepatic hypertrophy was observed in the model, along with macrovesicular steatosis. Smil/Lstr combo administration effectively restored the lipid profile and alleviated hepatic hypertrophy in the HFD zebrafish. In oleic-acid stimulated hepatocytes, Smil/Lstr combo markedly reduced lipid accumulation and cell damage. Subsequently, based on zebrafish phenotypic screening, the natural phthalide senkyunolide I (SEI) was identified as a major molecule mediating the lipid-lowering activities of Smil/Lstr combo in the liver. Moreover, SEI upregulated the expression of the lipid metabolism regulator PPARα and downregulated fatty acid translocase CD36, while a PPARα antagonist sufficiently blocked the regulatory effect of SEI on hepatic steatosis. Finally, the roles of SEI on hepatic lipid accumulation and PPARα signaling were further verified in the hamster model.

CONCLUSIONS

We proposed a zebrafish-based screening strategy for modulators of hepatic steatosis and discovered the regulatory roles of Smil/Lstr combo and its component SEI on liver lipid accumulation and PPARα signaling, suggesting their potential value as novel candidates for NAFLD treatment.

The causal relationship between bacterial pneumonia and diabetes: a two-sample mendelian randomization study

BACKGROUND

Previous observational studies have established the high prevalence of bacterial pneumonia in diabetic patients, which in turn leads to increased mortality. However, the presence of a causal connection between bacterial pneumonia and diabetes remains unobserved.

METHODS

We chose genome-wide significant (Ρ < 1 × 10-5 and Ρ < 1 × 10-6) and independent (r2 < 0.001) single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) to proceed a bidirectional two-sample MR study. The extracted SNPs explored the relationship between bacterial pneumonia and diabetes by Inverse variance weighted (IVW), MR-Egger, and weighted median methods. In addition, we conducted the Heterogeneity test, the Pleiotropy test, MR-presso and the Leave-one-out (LOO) sensitivity test to validate the reliability of results.

RESULTS

In an MR study with bacterial pneumonia as an exposure factor, four different types of diabetes as outcome. It was observed that bacterial pneumonia increases the incidence of GDM (OR = 1.150 (1.027-1.274, P = 0.011) and T1DM (OR = 1.277 (1.024-1.531), P = 0.016). In the reverse MR analysis, it was observed that GDM (OR = 1.112 (1.023-1.201, P = 0.009) is associated with an elevated risk of bacterial pneumonia. However, no significant association was observed bacterial pneumonia with T1DM and other types of diabetes (P > 0.05).

CONCLUSION

This study utilizing MR methodology yields robust evidence supporting a bidirectional causal association between bacterial pneumonia and GDM. Furthermore, our findings suggest a plausible causal link between bacterial pneumonia and T1DM.

Characterizing the effects of Dechlorane Plus on β-cells: a comparative study across models and species

Epidemiological studies consistently link environmental toxicant exposure with increased Type 2 diabetes risk. Our study investigated the diabetogenic effects of a widely used flame retardant, Dechlorane Plus (DP), on pancreatic β-cells using rodent and human model systems. We first examined pancreas tissues from male mice exposed daily to oral gavage of either vehicle (corn oil) or DP (10, 100, or 1000 μg/kg per day) and fed chow or high fat diet for 28-days in vivo. DP exposure did not affect islet size or endocrine cell composition in either diet group. Next, we assessed the effect of 48-hour exposure to vehicle (DMSO) or DP (1, 10, or 100 nM) in vitro using immortalized rat β-cells (INS-1 832/3), primary mouse and human islets, and human stem-cell derived islet-like cells (SC-islets). In INS-1 832/3 cells, DP did not impact glucose-stimulated insulin secretion (GSIS) but significantly decreased intracellular insulin content. DP had no effect on GSIS in mouse islets or SC-islets but had variable effects on GSIS in human islets depending on the donor. DP alone did not affect insulin content in mouse islets, human islets, or SC-islets, but mouse islets co-exposed to DP and glucolipotoxic (GLT) stress conditions (28.7 mM glucose + 0.5 mM palmitate) had reduced insulin content compared to control conditions. Co-exposure of mouse islets to DP + GLT amplified the upregulation of Slc30a8 compared to GLT alone. Our study highlights the importance and challenges of using different in vitro models for studying chemical toxicity.

Serum from pregnant donors induces human beta cell proliferation

Pancreatic beta cells are among the slowest replicating cells in the human body and have not been observed to increase in number except during the fetal and neonatal period, in cases of obesity, during puberty, as well as during pregnancy. Pregnancy is associated with increased beta cell mass to meet heightened insulin demands. This phenomenon raises the intriguing possibility that factors present in the serum of pregnant individuals may stimulate beta cell proliferation and offer insights into expansion of the beta cell mass for treatment and prevention of diabetes. The primary objective of this study was to test the hypothesis that serum from pregnant donors contains bioactive factors capable of inducing human beta cell proliferation. An immortalized human beta cell line with protracted replication (EndoC-βH1) was cultured in media supplemented with serum from pregnant and non-pregnant female and male donors and assessed for differences in proliferation. This experiment was followed by assessment of proliferation of primary human beta cells. Sera from five out of six pregnant donors induced a significant increase in the proliferation rate of EndoC-βH1 cells. Pooled serum from the cohort of pregnant donors also increased the rate of proliferation in primary human beta cells. This study demonstrates that serum from pregnant donors stimulates human beta cell proliferation. These findings suggest the existence of pregnancy-associated factors that can offer novel avenues for beta cell regeneration and diabetes prevention strategies. Further research is warranted to elucidate the specific factors responsible for this effect.

Small RNA-Seq and real time rt-qPCR reveal islet miRNA released under stress conditions

Replacement of beta cells through transplantation is a potential therapeutic approach for individuals with pancreas removal or poorly controllable type 1 diabetes. However, stress and death of beta cells pose significant challenges. Circulating miRNA has emerged as potential biomarkers reflecting early beta cell stress and death, allowing for timely intervention. The aim of this study was to identify miRNAs as potential biomarkers for beta cell health. Literature review combined with small RNA sequencing was employed to select islet-enriched miRNA. The release of those miRNA was assessed by RT-qPCR in vivo, using a streptozotocin induced diabetes mouse model and in vitro, through mouse and human islets exposed to varying degrees of hypoxic and cytokine stressors. Utilizing the streptozotocin induced model, we identified 18 miRNAs out of 39 candidate islet-enriched miRNA to be released upon islet stress in vivo. In vitro analysis of culture supernatants from cytokine and/or hypoxia stressed islets identified the release of 45 miRNAs from mouse and 8 miRNAs from human islets. Investigation into the biological pathways targeted by the cytokine- and/or hypoxia-induced miRNA suggested the involvement of MAPK and PI3K-Akt signaling pathways in both mouse and human islets. We have identified miRNAs associated with beta cell health and stress. The findings allowed us to propose a panel of 47 islet-related human miRNA that is potentially valuable for application in clinical contexts of beta cell transplantation and presymptomatic early-stage type 1 diabetes.

Decreased islet amyloid polypeptide staining in the islets of insulinoma patients

Islet amyloid polypeptide (IAPP) is a factor that regulates food intake and is secreted from both pancreatic islets and insulinoma cells. Here, we aimed to evaluate IAPP immunohistochemically in islets or insulinoma cells in association with clinical characteristics. We recruited six insulinoma patients and six body mass index-matched control patients with pancreatic diseases other than insulinoma whose glucose tolerance was confirmed to be normal preoperatively. IAPP and IAPP-insulin double staining were performed on pancreatic surgical specimens. We observed that the IAPP staining level and percentage of IAPP-positive beta cells tended to be lower (p = 0.1699) in the islets of insulinoma patients than in those of control patients, which might represent a novel IAPP expression pattern under persistent hyperinsulinemia and hypoglycemia.

COVID-19 vaccines and blood glucose control: Friend or foe?

PURPOSE

To overview the recent literature regarding the relationship between COVID-19 vaccines and glycemic control.

METHODS

Data were extracted from text and tables of all available articles published up to September 2023 in PubMed Database describing glucose homeostasis data in subjects exposed to COVID-19 vaccines, focusing on patients with diabetes mellitus (DM).

RESULTS

It is debated if the immune system impairment observed in diabetic patients makes them susceptible to lower efficacy of vaccines, but evidence suggests a possible improvement in immune response in those with good glycemic control. Despite their proven protective role lowering infection rates and disease severity, COVID-19 vaccines can result in diabetic ketoacidosis, new-onset diabetes, or episodes of hyper- or hypoglycemia.

CONCLUSIONS

Evidence with COVID-19 vaccines highlights the strong relationship existing between DM and immune system function. Clinicians should strive to achieve optimal glucose control before vaccination and promptly manage possible glucose homeostasis derangement following vaccine exposure.

3D evaluation of the extracellular matrix of hypoxic pancreatic islets using light sheet fluorescence microscopy

Pancreatic islet transplantation is a promising treatment for type 1 diabetes, but the survival and function of transplanted islets are hindered by the loss of extracellular matrix (ECM) during islet isolation and by low oxygenation upon implantation. This study aimed to evaluate the impact of hypoxia on ECM using a cutting-edge imaging approach based on tissue clearing and 3D microscopy. Human and rat islets were cultured under normoxic (O2 21%) or hypoxic (O2 1%) conditions. Immunofluorescence staining targeting insulin, glucagon, CA9 (a hypoxia marker), ECM proteins (collagen 4, fibronectin, laminin), and E-cadherin (intercellular adhesion protein) was performed on fixed whole islets. The cleared islets were imaged using Light Sheet Fluorescence Microscopy (LSFM) and digitally analyzed. The volumetric analysis of target proteins did not show significant differences in abundance between the experimental groups. However, 3D projections revealed distinct morphological features that differentiated normoxic and hypoxic islets. Under normoxic conditions, ECM could be found throughout the islets. Hypoxic islets exhibited areas of scattered nuclei and central clusters of ECM proteins, indicating central necrosis. E-cadherin was absent in these areas. Our results, demonstrating a diminution of islets' functional mass in hypoxia, align with the functional decline observed in transplanted islets experiencing low oxygenation after grafting. This study provides a methodology combining tissue clearing, multiplex immunofluorescence, Light Sheet Fluorescence Microscopy, and digital image analysis to investigate pancreatic islet morphology. This 3D approach allowed us to highlight ECM organizational changes during hypoxia from a morphological perspective.

Maternal betel quid use during pregnancy and child growth: a cohort study from rural Bangladesh

BACKGROUND

Chewing betel quid (BQ) - a preparation commonly containing areca nut and slaked lime wrapped in betel leaf - is entrenched in South Asia. Although BQ consumption during pregnancy has been linked to adverse birth outcomes, its effect on postnatal growth remains largely unexplored.

OBJECTIVE

We examined the associations of BQ use during pregnancy with children's height-for-age and body mass index-for-age z-scores (HAZ and BAZ, respectively) and fat and fat-free mass along with sex-based differences in association in rural Bangladesh.

METHODS

With a prospective cohort design, we assessed BQ use among mothers enrolled in the Preterm and Stillbirth Study, Matlab (n = 3140) with a structured questionnaire around early third trimester. Children born to a subset of 614 women (including 134 daily users) were invited to follow-up between October 2021 and January 2022. HAZ and BAZ were calculated from anthropometric assessment, and fat and fat-free mass were estimated using bioelectric impedance. Overall and sex-specific multiple linear regression models were fitted.

RESULTS

Growth data were available for 501 children (mean age 4.9 years): 43.3% of them were born to non-users, 35.3% to those using prior to or less-than-daily during the survey, and 21.3% to daily users. No statistically significant associations were observed after adjusting for sex, parity, maternal height and education, and household wealth.

CONCLUSIONS

There was no effect of BQ use during pregnancy on postnatal growth in this study. Longitudinal studies following up those born to heavy users beyond childhood are warranted for capturing long-term implications of prenatal BQ exposure.

Contextual awareness, response and evaluation (CARE) of diabetes in poor urban communities in Ghana: the CARE diabetes project qualitative study protocol

Diabetes remains a major, global clinical and public health threat with consistent rises in prevalence around the world over the past four decades. Two-thirds of the projected increases in global diabetes prevalence to 2045 are expected to come from low- and middle-income countries, including those in sub-Saharan Africa. Ghana is typical of this trend. However, there are gaps in evidence regarding the appropriate development of interventions and well-targeted policies for diabetes prevention and treatment that pay due attention to relevant local conditions and influences. Due consideration to community perspectives of environmental influences on the causes of diabetes, access to appropriate health services and care seeking for diabetes prevention and management is warranted, especially in urban settings. The 'Contextual Awareness, Response and Evaluation (CARE): Diabetes in Ghana' project is a mixed methods study in Ga Mashie, Accra. An epidemiological survey is described elsewhere. Six qualitative studies utilising a range of methodologies are proposed in this protocol to generate a contextual understanding of type 2 diabetes mellitus in an urban poor population. They focus on community, care provider, and policy stakeholder perspectives with a focus on food markets and environmental influences, the demand and supply of health services, and the history of the Ga Mashie community and its inhabitants. The results will be shared with the community in Ga Mashie and with health policy stakeholders in Ghana and other settings where the findings may be usefully transferable for the development of community-based interventions for diabetes prevention and control.