Investigating the Association between Diabetic Neuropathy and Vitamin D in Emirati Patients with Type 2 Diabetes Mellitus.

(1) Background: Vitamin D deficiency is a common public health problem in the United Arab Emirates (UAE) and globally, and interestingly, improvements in diabetic neuropathy after taking Vitamin D supplementation for a short time have been reported. Despite living in a country that is sunny all year round, hypovitaminosis D, indicated by an obvious low serum vitamin D level, has been recurrently noted in the UAE, as well as in the surrounding Arabian Gulf countries. This problem is receiving much attention and attracting clinical and academic interest. Therefore, the main objective of the present study is to identify the association, if any, between vitamin D deficiency and the development of diabetic neuropathy in the UAE population with T2DM. (2) Methods: a total of 600 Emirati patients (male and female) with T2DM, aged between 20 and 80, were recruited from University Hospital Sharjah (UHS). The medical records of the patients were reviewed and analyzed. (3) Results: The results of the present study showed that among the 600 patients, 50% were affected with diabetic neuropathy. Vitamin D level in patients with neuropathy were estimated to be around 20 ng/mL (IQR 14-25), and vitamin D levels were significantly higher (33 ng/mL (IQR 20-42)) among patients without neuropathy, with p < 0.001. Another important finding was that patients without neuropathy had a better vitamin D status, with only 19% being deficient and 18% having insufficient vitamin D levels, compared to patients with neuropathy, where 39% were deficient (vitamin D < 20 ng/mL) and 44% had insufficient vitamin D levels (20-30 ng/mL). (4) Conclusion: The findings of the present study show that the prevalence of vitamin D deficiency (low serum 25-hydroxy vitamin D 25-OHD level) is significantly high in diabetic neuropathy in Emirati patients with T2DM.

Effects of Varying Glucose Concentrations on ACE2's Hypothalamic Expression and Its Potential Relation to COVID-19-Associated Neurological Dysfunction.

The coronavirus disease 2019 (COVID-19) pandemic has negatively impacted millions of lives, despite several vaccine interventions and strict precautionary measures. The main causative organism of this disease is the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) which infects the host via two key players: the angiotensin-converting enzyme 2 (ACE2) and the transmembrane protease, serine 2 (TMPRSS2). Some reports revealed that patients with glycemic dysregulation could have increased susceptibility to developing COVID-19 and its related neurological complications. However, no previous studies have looked at the involvement of these key molecules within the hypothalamus, which is the central regulator of glucose in the brain. By exposing embryonic mouse hypothalamic neurons to varying glucose concentrations, we aimed to investigate the expression of ACE2 and TMPRSS2 using quantitative real time polymerase chain reaction and western blotting. A significant and time-dependent increase and decrease was observed on the viability of hypothalamic neurons with increasing and decreasing glucose concentrations, respectively (p < 0.01 and p < 0.001, respectively). Under the same increasing and decreasing glucose conditions, the expression of hypothalamic ACE2 also revealed a significant and time-dependent increase (p < 0.01). These findings suggest that SARS-CoV-2 invades the hypothalamic circuitry. In addition, it highlights the importance of strict glycemic control for COVID-19 in diabetic patients.

COVID-19 and Neurological Impairment: Hypothalamic Circuits and Beyond.

In December 2019, a novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, the capital of Hubei, China. The virus infection, coronavirus disease 2019 (COVID-19), represents a global concern, as almost all countries around the world are affected. Clinical reports have confirmed several neurological manifestations in COVID-19 patients such as headaches, vomiting, and nausea, indicating the involvement of the central nervous system (CNS) and peripheral nervous system (PNS). Neuroinvasion of coronaviruses is not a new phenomenon, as it has been demonstrated by previous autopsies of severe acute respiratory syndrome coronavirus (SARS-CoV) patients who experienced similar neurologic symptoms. The hypothalamus is a complex structure that is composed of many nuclei and diverse neuronal cell groups. It is characterized by intricate intrahypothalamic circuits that orchestrate a finely tuned communication within the CNS and with the PNS. Hypothalamic circuits are critical for maintaining homeostatic challenges including immune responses to viral infections. The present article reviews the possible routes and mechanisms of neuroinvasion of SARS-CoV-2, with a specific focus on the role of the hypothalamic circuits in mediating the neurological symptoms noted during COVID-19 infection.

Potential role of hypothalamic microRNAs in regulation of FOS and FTO expression in response to hypoglycemia.

Hypoglycemia-associated autonomic failure (HAAF) is a serious complication of diabetes which is associated with the absence of physiological homeostatic counter-regulatory mechanisms that are controlled by the hypothalamus and sympathetic nervous system. Identification of biomarkers for early detection of HAAF requires an advanced understanding of molecular signature of hypoglycemia which is yet to be identified. The outcomes of the present study have shown that the viability and the apoptotic rate of the hypothalamic neurons (mHypoE-N39) were decreased significantly due to hypoglycemia in a dose-dependent fashion (p < 0.05). Although there are more than 1000 miRNAs differentially expressed in hypothalamus, only twelve miRNAs (miR-7a, miR-7b, miR-9, miR-29b, miR-29c, miR-30a, miR-30b, miR-30c, miR-101b-3p, miR-181a-5p, miR-378-3p and miR-873-5p) were correlated to two main hypothalamic regulatory proteins, FOS and FTO. Expression of these proteins was very sensitive to hypoglycemia. We demonstrated that hypoglycemia modulates the expression of hypothalamic miRNAs that are related to FOS and FTO.