Genetic Factors Associated with the Development of Neuropathy in Type 2 Diabetes.

Neuropathy is a serious and frequent complication of type 2 diabetes (T2DM). This study was carried out to search for genetic factors associated with the development of diabetic neuropathy by whole exome sequencing. For this study, 24 patients with long-term type 2 diabetes with neuropathy and 24 without underwent detailed neurological assessment and whole exome sequencing. Cardiovascular autonomic function was evaluated by cardiovascular reflex tests. Heart rate variability was measured by the triangle index. Sensory nerve function was estimated by Neurometer and Medoc devices. Neuropathic symptoms were characterized by the neuropathy total symptom score (NTSS). Whole exome sequencing (WES) was performed on a Thermo Ion GeneStudio S5 system determining the coding sequences of approximately 32,000 genes comprising 50 million base pairs. Variants were detected by Ion Reporter software and annotated using ANNOVAR, integrating database information from dbSNP, ClinVar, gnomAD, and OMIM. Integrative genomics viewer (IGV) was used for visualization of the mapped reads. We have identified genetic variants that were significantly associated with increased (22-49-fold) risk of neuropathy (rs2032930 and rs2032931 of recQ-mediated genome instability protein 2 (RMI2) gene), rs604349 of myosin binding protein H like (MYBPHL) gene and with reduced (0.07-0.08-fold) risk (rs917778 of multivesicular body subunit 12B (MVB12B) and rs2234753 of retinoic acid X receptor alpha (RXRA) genes). The rs2032930 showed a significant correlation with current perception thresholds measured at 5 Hz and 250 Hz for n. medianus (p = 0.042 and p = 0.003, respectively) and at 5 Hz for n. peroneus (p = 0.037), as well as the deep breath test (p = 0.022) and the NTSS (p = 0.023). The rs2032931 was associated with current perception thresholds (p = 0.003 and p = 0.037, respectively), deep breath test (p = 0.022), and NTSS (p = 0.023). The rs604349 correlated with values measured at 2000 (p = 0.049), 250 (p = 0.018), and 5 Hz (p = 0.005) for n. medianus, as well as warm perception threshold measured by Medoc device (p = 0.042). The rs2234753 showed correlations with a current perception threshold measured at 2000 Hz for n. medianus (p = 0.020), deep breath test (p = 0.040), and NTSS (p = 0.003). There was a significant relationship between rs91778 and cold perception threshold (p = 0.013). In our study, genetic variants have been identified that may have an impact on the risk of neuropathy developing in type 2 diabetic patients. These results could open up new opportunities for early preventive measures and might provide targets for new drug developments in the future.

The analysis of the effect of the COVID-19 pandemic on patients with hereditary angioedema type I and type II.

Due to the similarity between the pathomechanism of SARS-CoV-2 infections and hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE), a possibility emerged that C1-INH-HAE may worsen the course of the infection, or that the infection may influence the severity of angioedema (HAE) attacks in C1-INH-HAE patients. Our study aimed to evaluate the effects of the COVID-19 pandemic on the quality of life (QoL) of Hungarian C1-INH-HAE patients, and to survey the acute course of the infection, post COVID symptoms (PCS), vaccination coverage and the side effects of vaccines in this patient population. 93 patients completed our questionnaire between 1st July 2021 and 31st October 2021. In this same period and between March 2019 and March 2020, 63 patients completed the angioedema quality of life questionnaire (AE-QoL). Out of those patients infected with SARS-CoV-2 in the examined period (18/93 patients; 19%), 5% required hospitalization, 28% experienced HAE attacks in the acute phase of the infection, and 44% experienced PCS. A total number of 142 doses of vaccines were administered to the patients. Serious vaccine reactions did not occur in any case, 4 (5%) out of the 73 vaccinated patients experienced HAE attacks. No significant difference (p = 0.59) was found in the median of the AE-QoL total score, or in the number of HAE attacks prior and during the pandemic. Based on our study, HAE patients did not experience more serious SARS-CoV-2 infection, and it did not aggravate the course of HAE either. Changes in the QoL were not significant, and vaccines were safe in HAE patients.

Vitamin D in the Prevention and Treatment of Diabetic Neuropathy.

PURPOSE: Neuropathy is one of the most important complications of diabetes. According to recent advances, vitamin D deficiency might play a role in the development and progression of diabetic neuropathy. Moreover, therapeutic vitamin D supplementation has the potential to improve this condition. The aim of the present review was to summarize new data available in this area. METHODS: The PubMed database was searched for articles written in English and published through September 2021, using combinations of the following key words: vitamin D, diabetes, diabetes mellitus, diabetic neuropathy, polyneuropathy, peripheral neuropathy, cardiac autonomic neuropathy, supplementation, and therapy. FINDINGS: A number of studies have suggested that vitamin D deficiency can play a significant role in the development of peripheral neuropathy, diabetic foot ulcers, as well as cardiovascular autonomic neuropathy in patients with type 2 diabetes. Vitamin D supplementation might serve as an effective adjuvant therapy for neuropathic pain and may slow or stop the progression of neural damage. IMPLICATIONS: Vitamin D therapy for diabetic complications could be a reliable option; however, further studies are needed to confirm this notion.

Diabetic Cardiovascular Autonomic Neuropathy, the Handgrip Test and Ambulatory Blood Pressure Monitoring Parameters: Are There Any Diagnostic Implications?

Cardiovascular autonomic neuropathy (CAN) is a common complication of diabetes mellitus. Cardiovascular reflex tests (CARTs) are the gold standard in the diagnosis of CAN, but the handgrip test is no longer recommended to be performed. Previously, the inverse association between the presence of hypertension and handgrip test abnormality was demonstrated and hypertension as major cause for excessive diastolic blood pressure rise during handgrip testing in diabetic individuals proposed. The aim of the present study is to describe more precisely the association between handgrip test and hypertension by performing ambulatory blood pressure monitoring (ABPM) among diabetic patients. A more comprehensive evaluation of the relationship between cardiovascular autonomic function, hypertension and the handgrip test was targeted using heart rate variability (HRV) analysis. Our study involved 163 patients with diabetes. Cardiovascular autonomic neuropathy was assessed by the CARTs and sustained handgrip test was performed. All patients underwent ABPM and HRV analysis well. CAN was diagnosed in 69 patients. Significant associations were found between the diastolic blood pressure increase in response to handgrip exercise and the 24-h (rho = 0.245, p = 0.003), daytime (rho = 0.230, p = 0.005) and night-time (rho = 0.230, p = 0.006) mean systolic and 24-h diastolic (rho = 0.176, p = 0.034) blood pressure values, systolic blood pressure load (rho = 0.252, p = 0.003) and systolic (rho = 0.236, p = 0.005) and diastolic (rho = 0.165, p = 0.047) hyperbaric impacts. Higher values of ambulatory blood pressure monitoring parameters are associated with greater increases in diastolic blood pressure during isometric handgrip exercise. Diastolic blood pressure elevations during the handgrip test are also correlated, in order to diminished heart rate variability parameters attributable to parasympathetic dysfunction highlighting the pivotal role of sympathetic overactivity in evolving handgrip test results. Our study provides further evidence on the inverse association between handgrip test abnormality and hypertension in diabetic patients.

Why Not to Use the Handgrip Test in the Assessment of Cardiovascular Autonomic Neuropathy Among Patients with Diabetes Mellitus?

OBJECTIVE: Historically, a set of 5 Cardiovascular Autonomic Reflex Tests (CARTs) were considered to be the gold standard in the assessment of Cardiovascular Autonomic Neuropathy (CAN). However, measuring diastolic Blood Pressure (BP) response to sustained handgrip is omitted in recent guidelines. We aimed to assess the association between the handgrip and the other 4 tests as well as to identify determinants of the handgrip test results in diabetic patients. PATIENTS AND METHODS: 353 patients with diabetes (DM) were recruited (age: 60.2±7.4 years; female: 57.2%; BMI: 29.3±2.1 kg/m2; DM duration: 15.6±9.9 years; HbA1c: 7.8±1.4% (66 mmol/mol); with type 1 DM: 18.1%). CAN was assessed by 5 CARTs: the deep breathing test, Valsalva ratio, 30/15 ratio, handgrip and orthostatic hypotension test. RESULTS: Sensitivity and specificity of the handgrip test in the diagnosis of definite CAN were 24.6% (95%CI 17.7-33.1%) and 79.4% (95%CI 73.3-84.4%), respectively. Results of the handgrip test did not show any association with those of the deep-breathing test (y=0.004, p=0.563), 30/15 ratio (y=0.282, p=0.357), Valsalva ratio (y=-0.058, p=0.436) and orthostatic hypotension (y=-0.026, p=0.833). Handgrip test abnormality showed an independent association with higher initial diastolic BP (OR 1.05, p=0.0009) and an independent inverse association with the presence of hypertension (OR=0.42, p=0.006). CONCLUSION: Our data confirm that the handgrip test should no longer be part of the cardiovascular autonomic testing being highly dependent on hypertensive status and baseline diastolic BP. Exaggerated exercise pressor response is proposed as putative mechanism for the inverse association between abnormal results of the handgrip test and hypertension. Adequate CARTs are important to allow their use in clinical trials and for the prevention of DM-associated complications by initiating early treatment.

Is there an association between diabetic neuropathy and low vitamin D levels?

In the past few years, the effects of vitamin D that go beyond its relationship with bone metabolism have come into the focus of scientific attention. Research concerning diabetes and its complications has become a public health priority. An increasing number of reports link vitamin D deficiency to diabetes; however, so far, there has only been limited and contradictory data available on the correlation between diabetic peripheral neuropathy and vitamin D. Studies of people with type 2 diabetes confirmed the relationship between vitamin D deficiency and neuropathy incidence as well as the severity of the symptoms caused by neuropathy. The latest studies are also suggesting a relationship between the incidence of plantar ulcers and vitamin D deficiency.

Heart rate variability is severely impaired among type 2 diabetic patients with hypertension.

INTRODUCTION: The aim of our study was to evaluate the relative effect of diabetes and hypertension on heart rate variability. RESEARCH DESIGN AND METHODS: Four age-matched groups including type 2 diabetic patients with and without hypertension, non-diabetic patients with essential hypertension and healthy control subjects were studied. Autonomic function was evaluated by the standard cardiovascular reflex tests and 24-hour heart rate variability measurement. Heart rate variability was characterized by the triangular index value and by the spectral components of the frequency domain analysis. RESULTS: According to the two-way analysis of variance on ranks, all parameters were influenced negatively by diabetes (heart rate variability triangular index: p < 0.001; low-frequency component: p < 0.0001; high-frequency component: p < 0.001; and total power: p < 0.0001), whereas hypertension had a negative effect only on the low-frequency component (p < 0.05). The interaction between hypertension and diabetes was not significant, indicating that their effects on the heart rate variability parameters are additive. Beat-to-beat variation upon deep breathing, the most sensitive cardiovascular reflex test was also negatively influenced by both diabetes (p < 0.001) and hypertension, (p < 0.05), and their effects were additive. CONCLUSIONS: Diabetes appears to have a greater effect on autonomic dysfunction compared with hypertension. Patients suffering from both diabetes and hypertension are at the highest risk of reduced heart rate variability. Early assessment of the autonomic nerve function is suggested in diabetic patients with hypertension.

[Vitamin D and neuropathy]. / D-vitamin és neuropathia.

Diabetes is a widespread disease and, therefore, studies dealing with diabetes and its complications are very important for public health. Numerous reports link vitamin D deficiency to the increased risk of diabetes mellitus and complications such as neuropathy. However, there are limited and conflicting data available on vitamin D deficiency in patients with diabetic peripheral neuropathy. Studies in type 2 diabetics confirmed the relationship between vitamin D deficiency and incidence of neuropathy. Recent reports suggest a relationship between the incidence of plantar ulcers and vitamin D deficiency.