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Recurrent non-severe hypoglycemia (RH) in patients with diabetes might be associated with cognitive impairment. Previously, we found that mitochondrial dysfunction plays an important role in this pathological process; however, the mechanism remains unclear. The objective of this study was to determine the molecular mechanisms of mitochondrial damage associated with RH in diabetes mellitus (DM). We found that RH is associated with reduced hippocampal mitophagy in diabetic mice, mainly manifested by reduced autophagosome formation and impaired recognition of impaired mitochondria, mediated by the PINK1/Parkin pathway. The same impaired mitophagy initiation was observed in an in vitro high-glucose cultured astrocyte model with recurrent low-glucose interventions. Promoting autophagosome formation and activating PINK1/Parkin-mediated mitophagy protected mitochondrial function and cognitive function in mice. The results showed that impaired mitophagy is involved in the occurrence of mitochondrial dysfunction, mediating the neurological impairment associated with recurrent low glucose under high glucose conditions., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organization that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in or the review of, the manuscript entitled., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aims: This study examined the association between hypoglycemia and mild cognitive impairment (MCI) among patients with type 2 diabetes mellitus (T2DM) and identified risk factors for MCI in patients with hypoglycemia., Methods: In this retrospective study, 328 patients with T2DM were screened in 2019 and followed up in 2022. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA). The diagnosis of MCI was based on established criteria. Risk ratio (RR) with 95 % confidence intervals (CI) was calculated to estimate the risk of MCI. Univariate and multivariate logistic regression analyses were conducted to identify risk factors for MCI in those with hypoglycemia., Results: Patients with hypoglycemia had lower cognitive performance 3 years later. The RR of MCI was 2.221 (95 % CI 1.269-3.885). Multivariate logistic analysis showed that low grip strength, existing diabetic retinopathy (DR), and multiple hypoglycemia episodes were associated with higher odds of MCI in patients with hypoglycemia (adjusted odds ratio [OR] 0.909 [95 % CI 0.859-0.963]), 3.078 [95 % CI 1.158-12.358], and 4.642 [95 % CI 1.284-16.776], respectively, all P < 0.05)., Conclusions: Hypoglycemia increased MCI risk among patients with T2DM. Low grip strength, DR, and multiple hypoglycemia episodes may be potential risk factors for hypoglycemia-associated MCI., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Hypoglycemia is a common adverse reaction to glucose-lowering treatment. Diabetes mellitus (DM) combined with recurrent nonsevere hypoglycemia (RH) can accelerate cognitive decline. Currently, the metabolic pattern changes in cognition-related brain regions caused by this combined effect of DM and RH (DR) remain unclear. In this study, we first characterized the metabolic profiles of the hippocampus in mice exposed to DR using non-targeted metabolomic platforms. Our results showed that DR induced a unique metabolic pattern in the hippocampus, and several significant differences in metabolite levels belonging to the histidine metabolism pathway were discovered. Based on these findings, in the follow-up experiment, we found that histidine treatment could attenuate the cognitive impairment and rescue the neuronal and synaptic damage induced by DR in the hippocampus, which are closely related to ameliorated mitochondrial injury. These findings provide new insights into the metabolic mechanisms of the hippocampus in the progression of DR, and l-histidine supplementation may be a potential metabolic therapy in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Severe hypoglycemia is closely related to adverse cardiovascular outcomes in patients with diabetes; however, the specific mechanism remains unclear. We previously found that severe hypoglycemia aggravated myocardial injury and cardiac dysfunction in diabetic mice, and that the mechanism of damage was related to mitochondrial oxidative stress and dysfunction. Based on the key regulatory role of mitophagy in mitochondrial quality control, this study aimed to further explore whether the myocardial damage caused by severe hypoglycemia is related to insufficient mitophagy and to clarify their underlying regulatory relationship. After severe hypoglycemia, mitochondrial reactive oxygen species increased, mitochondrial membrane potential and ATP content decreased, and pathological mitochondrial damage was aggravated in the myocardium of diabetic mice. This was accompanied by decreased mitochondrial biosynthesis, increased fusion, and downregulated PTEN-induced kinase 1 (PINK1)/Parkin-dependent mitophagy. Treating diabetic mice with the mitophagy activator and polyphenol metabolite urolithin A activated PINK1/Parkin-dependent mitophagy, reduced myocardial oxidative stress and mitochondrial damage associated with severe hypoglycemia, improved mitochondrial function, alleviated myocardial damage, and ultimately improved cardiac function. Thus, we provide insight into the prevention and treatment of diabetic myocardial injury caused by hypoglycemia to reduce adverse cardiovascular outcomes in patients with diabetes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The present study aimed to determine the relationship between astrocytes and recurrent non-severe hypoglycemia (RH) 2 -associated cognitive decline in diabetes. RH induced cognitive impairment and neuronal cell death in the cerebral cortex of diabetic mice, accompanied by excessive activation of astrocytes. Levels of the neurotrophins BDNF and GDNF, together with BDNF and GDNF- related signaling, were downregulated by RH. In vitro, recurrent low glucose (RLG) 3 impaired cell viability and induced apoptosis of high-glucose cultured astrocytes. Accumulating mitochondrial ROS and dysregulated mitochondrial functions, including abnormal morphology, decreased membrane potential, downregulated ATP levels, and disrupted bioenergetic status, were observed in these cells. SS-31 mediated protection of mitochondrial functions reversed RLG-induced cell viability defects and neurotrophin production. These findings demonstrate that RH induced astrocyte overactivation and mitochondrial dysfunction, leading to astrocyte-derived neurotrophin disturbance, which might contribute to diabetic cognitive decline. Targeting astrocyte mitochondria might represent a neuroprotective therapy for hypoglycemia-associated neurodegeneration in diabetes., (Copyright © 2021. Published by Elsevier B.V.)