Effects of L-carnitine supplementation on the quality of life in diabetic patients with muscle cramps

Biomedical role of L-carnitine in several organ systems, cellular tissues, and COVID-19

Carnitine is a conditionally necessary vitamin that aids in energy creation and fatty acid metabolism. Its bioavailability is higher in vegetarians than in meat-eaters. Deficits in carnitine transporters occur because of genetic mutations or in conjunction with other illnesses. Carnitine shortage can arise in health issues and diseases-including hypoglycaemia, heart disease, starvation, cirrhosis, and ageing-because of abnormalities in carnitine control. The physiologically active form of L-carnitine supports immunological function in diabetic patients. Carnitine has been demonstrated to be effective in the treatment of Alzheimer's disease, several painful neuropathies, and other conditions. It has been used as a dietary supplement for the treatment of heart disease, and it also aids in the treatment of obesity and reduces blood glucose levels. Therefore, L-carnitine shows the potential to eliminate the influences of fatigue in COVID-19, and its consumption is recommended in future clinical trials to estimate its efficacy and safety. This review focused on carnitine and its effect on tissues, covering the biosynthesis, metabolism, bioavailability, biological actions, and its effects on various body systems and COVID-19.

Relationship Between Muscle Cramps and Diabetic Retinopathy in Patients with Type 2 Diabetes

AIM

Patients with type 2 diabetes (T2DM) often suffer from muscle cramps of varying severity. Studies have shown that muscle cramp is closely related to local microcirculation perfusion disorders. Diabetic retinopathy can not only reflect the microcirculation perfusion in the eye but also the systemic microcirculation in patients with diabetes. The aims of this study were to investigate the relationship between muscle cramps and diabetic retinopathy in patients with type 2 diabetes.

METHODS

A total of 150 adult patients with type 2 diabetes were enrolled and administered a questionnaire on muscle cramping, along with a visual analogue scale for pain. Diabetic retinopathy (DR) was determined by using fundus photography and graded as non-proliferative DR (NPDR) and proliferative DR (PDR). To assess whether there was an association between the muscle cramps and diabetic retinopathy, we conducted binomial logistic regression analysis.

RESULTS

Our study revealed that 48% of patients with T2DM experienced muscle cramps in the past three months. Patients self-reported suffering from muscle cramps exhibited a higher prevalence of DR (61% vs 38%, P < 0.05) and PDR (22% vs 4%, P < 0.05) compared with patients without muscle cramps. Serum 25-(OH) vitamin D, calcium, and magnesium levels were not significantly different between patients with and without muscle cramps. After adjusting for age, duration of diabetes, HbA1c, vitamin D, potassium, calcium, and magnesium, we demonstrated that diabetic retinopathy (OR, 2.18; 95% CI, 1.01-4.69; P< 0.05) and albumin (OR, 0.90; 95% CI, 0.82-1.00; P< 0.05) were highly associated with muscle cramps. Binomial logistic regression analysis also indicated that severity of DR is associated with muscle cramps. In addition, DR and PDR were found to be associated with muscle cramp frequency (P for trend < 0.05), duration (P for trend < 0.05), and pain severity (P for trend < 0.05).

CONCLUSION

Muscle cramps occur frequently in diabetes and are correlated with diabetic retinopathy and albumin. Patients with PDR exhibited a higher frequency, severity, and longer duration relative to those with NPDR or without DR. Our findings suggested that muscle cramps in individuals with T2DM might be a result of microvascular dysfunction. Modulation of microvascular perfusion might thus provide a therapeutic target for alleviating muscle cramps.

Effectiveness of 4-Week Oral Taurine Treatment for Muscle Cramps in Patients with Liver Cirrhosis: A Single-Arm Pilot Study

PURPOSE

Painful muscle cramps are a common complication in liver cirrhosis patients, and no effective treatment is available. This pilot study aimed to evaluate whether taurine supplementation improves muscle cramps in Korean cirrhotic patients.

MATERIALS AND METHODS

Ten cirrhotic patients who experienced muscle cramps one or more times/week were enrolled in this prospective single-arm study and administered with an oral taurine solution (1 g/50 mL) thrice a day for 4 weeks. Taurine was discontinued for the subsequent 4 weeks. The frequency and intensity of muscle cramps were evaluated using a questionnaire at weeks 0, 2, 4, 6, and 8 after the start of treatment.

RESULTS

At baseline, the median frequency of muscle cramps was six times/week, and all patients had severe pain. Muscle cramp scores (frequency×intensity) decreased in seven patients by weeks 4 and 8 after treatment initiation. Compared to baseline muscle cramp scores [median 21, interquartile range (IQR): 8-84], median muscle cramp scores were lower at week 4 (6.5, IQR: 3-12, p=0.126) and week 8 (5, IQR: 1.5-56, p=0.066). All five patients whose baseline plasma taurine levels were below the normal limit showed increased taurine levels at week 4; 60% of them experienced improvements in their muscle cramps. Of the five patients with normal or higher taurine levels, 80% experienced an improvement in symptoms at week 4. The safety and tolerability of the 4-week taurine therapy were excellent.

CONCLUSION

Oral taurine therapy for 4 weeks improved muscle cramps safely in cirrhotic patients.

Network pharmacology and metabolomics study on the intervention of traditional Chinese medicine Huanglian Decoction in rats with type 2 diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes mellitus (T2DM) is currently one of the most prominent and global chronic conditions. Huanglian Decoction (HLD) is a traditional Chinese medicine (TCM) preparation that has been used to treat T2DM for thousands of years in China. However, its mechanism of action at the metabolic level is still unclear. The purpose of this work is to study the mechanism of HLD in treating T2DM based on metabolomics and network pharmacology.

MATERIALS AND METHODS

In this study, metabolomics combined with network pharmacology was used to elucidate the therapeutic mechanism of HLD in T2DM. Serum samples were collected from rats with T2DM, induced by a high-sugar and high-fat diet combined with streptozotocin (STZ), to measure the levels of biochemical markers. Urinary metabolomics-based analysis using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) was conducted to evaluate the differential metabolites from multiple metabolic pathways.

RESULTS

After treatment with HLD for 4 weeks, biochemical indicators, including fasting blood glucose (FBG), blood lipid, fasting insulin (FINS), insulin sensitivity index (ISI), and homeostasis model assessment of insulin resistance (HOMA-IR), were significantly improved. Metabolomics results revealed that HLD regulated the biomarkers, such as cytosine, L-carnitine, betaine, phenylalanine, glucose, citrate, phenylpyruvate, and hippuric acid in glyoxylate and dicarboxylate metabolism, phenylalanine metabolism, and tricarboxylic acid (TCA) cycle. The combination of network pharmacology, metabolomics, western blot, and PCR showed that HLD can treat T2DM by enhancing the gene and protein expression levels of glucose transporter 4 (GLUT4), insulin receptor (INSR), and mitogen-activated protein kinase 1 (MAPK1) to interfere with glyoxylate and dicarboxylate metabolism.

CONCLUSIONS

The study based on metabolomics and network pharmacology indicated that HLD can improve T2DM through multiple targets and pathways, and it may be a useful alternative therapy for the treatment of T2DM.

Effect of l-carnitine supplementation on muscle cramps induced by stroke: A case report

l-carnitine, a compound responsible for transportation of acyl groups across cell membranes and modulating intracellular acyl-coenzyme A levels, is reported to reduce muscle cramps in patients with liver cirrhosis and diabetes and those on dialysis. A 79-y-old man with right-sided paralysis was admitted to our hospital and diagnosed with cerebral infarction. Nocturnal leg cramps appeared in the affected side and caused sleep disturbance. Supplementation with l-carnitine reduced the number of nocturnal leg cramps and alleviated sleep disturbance. It also plays an important role in nerve protection and treatment for carnitine deficiency. Patients with stroke-induced paralysis experience muscle wasting, which might reduce pooled carnitine in the affected side. This case suggests that stroke may cause localized carnitine deficiency, and l-carnitine supplementation might be effective for muscle cramps induced by stroke. To the best of our knowledge, this is the first case of l-carnitine supplementation for muscle cramps triggered by cerebral infarction.

Clinical features of liver cirrhosis patients with muscle cramping: a multicenter study

BACKGROUND

There has been a small number of reports mention the clinical features including quality of life (QOL) in liver cirrhosis (LC) patients with muscle cramping and therapeutic efficacy for muscle cramping. We evaluated clinical features of muscle cramping and treatments in such patients.

PATIENTS AND METHODS

Two-hundred and eighty-nine LC outpatients (70.6 ± 10.5 years old; male: female = 149: 140) were questioned regarding the presence or absence of muscle cramps within the last 3 months, including frequency, severity of related pain using a visual analogue scale, cramp locations, time of day, duration, sleep disturbance, daily activity decline, and being conscious of QOL decline. At the next hospital-visit, 3 or 4 months later, the subjects, who treated with medical intervention, received the same questionnaire.

RESULTS

Patients with muscle cramps (n = 160) included a higher percentage of females (53.8 vs. 41.9%, P = 0.045), worse Child-Pugh score (5: 6: 7: 8: 9: 10 = 91: 36: 15: 10: 4: 4 vs. 85: 25: 12: 5: 0: 2, P = 0.043) and lower platelet count (10.2 ± 4.7 vs. 11.8 ± 5.0 × 104/µl, P = 0.006) as compared to those without cramps (n = 129). Of the 160 with cramping, 82 (51.3%), received treatment with several types of medication, with l-carnitine the most administered drug (n = 66: 80.5%), and those also showed a tendency to complain about muscle cramps at night, sleep disturbance, reduced daily activity, and being conscious of QOL decline (each P < 0.01). We observed that frequency, visual analogue scale, sleep disturbance, daily activity, duration of muscle cramping, and being conscious of QOL decline were improved after the intervention (each P < 0.001, respectively).

CONCLUSION

Intervention for muscle cramping improves total QOL in LC patients with such symptom.

Urinary Metabolomics Study of the Intervention Effect of Hypoglycemic Decoction on Type 2 Diabetes Mellitus Rats Model

The hypoglycemic decoction (HD) is a traditional Chinese medicine (TCM) preparation for the treatment of diabetes mellitus (DM), with a remarkable therapeutic effect. However, its mechanism of action is still unclear at the metabolic level. In this study, the biochemical markers from type 2 DM (T2DM) rats, induced by a high-sugar and high-fat diet combined with streptozotocin (STZ), were detected. The metabolomics-based analysis using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was conducted to evaluate urine samples from control, model, metformin, and HD groups. After oral administration of HD for 28 days, the general state, weight, fasting blood glucose (FBG), blood lipid level, oral glucose tolerance test (OGTT), fasting insulin (FINS), insulin sensitivity index (ISI), and homeostasis model assessment of insulin resistance (HOMA-IR) were significantly improved (P < 0.01). The western blotting showed that HD can enhance the protein expression of glucose transporter 4 (GLUT4) and adenosine monophosphate-activated protein kinase (AMPK). The metabolomics results revealed that after treatment with HD, the levels of L-carnitine, 1-methyladenosine, 1-methylhistamine, and 3-indoleacrylic acid were upregulated and the levels of riboflavin, phenylalanine, atrolactic acid, 2-oxoglutarate, citrate, isocitrate, cortisol, and glucose were downregulated. The main mechanism may be closely related to the regulation of the tricarboxylic acid (TCA) cycle, phenylalanine metabolism, glyoxylate metabolism, and dicarboxylate metabolism. Additionally, it was also found that HD can regulate the protein expression of GLUT4 and AMPK to interfere with TCA cycle and carbohydrate metabolism to treat T2DM.