Effects of Prolonged Intermittent Fasting Model on Energy Metabolism and Mitochondrial Functions in Neurons.

Background: Calorie restriction (CR) during daily nutrition has been shown to affect the prognosis of many chronic diseases such as metabolic syndrome, diabetes, and aging. As an alternative nutrition model, prolonged intermittent fasting (PF) in humans is defined by the absence of food for more than 12 h. In our previous human studies, CR and PF models were compared and it was concluded that the two models might have differences in signal transduction mechanisms. We have investigated the effects of these models on neurons at the molecular level in this study. Methods: Neurons (SH-SY5Y) were incubated with normal medium (N), calorie-restricted medium (CR), fasting medium (PF), and glucose-free medium (G0) for 16 h. Simultaneously, ketone (beta-hydroxybutyrate; bOHB) was added to other experiment flasks containing the same media. Concentrations of lactate, lactate dehydrogenase (LDH), bOHB, and glucose were measured to demonstrate the changes in the energy metabolism together with the mitochondrial functions of cells. Citrate synthase activity and flow cytometric mitochondrial functions were investigated. Results: At the end of incubations, lactate and LDH levels were decreased and mitochondrial activity was increased in all ketone-added groups (P < .01) regardless of the glucose concentration in the environment. In the fasting model, these differences were more prominent. Conclusion: Our results demonstrated that neurons use ketones regardless of the amount of glucose, and bOHB-treated cells had positive changes in mitochondrial function. We conclude that the presence of bOHB might reverse neuron damage and that exogenous ketone treatment may be beneficial in the treatment of neurological diseases in the future.

Leukocyte telomere length as a compensatory mechanism in vitamin D metabolism.

Vitamin D deficiency is common among postmenopausal women. Telomere length can be a potential protective mechanism for age-related diseases. The objective of our study is to examine the association of vitamin D supplementation on leukocyte telomere length (LTL) in healthy postmenopausal women with vitamin D deficiency. The study was designed as a placebo-controlled study to investigate the short-term effects of vitamin D supplementation and seasonal changes on vitamin D related parameters, including 25(OH)D, 1,25(OH)2D parathormone (PTH), Vitamin D binding protein (VDBP), vitamin D receptor (VDR), and telomere length in a cohort of postmenopausal women (n = 102). The group was divided as supplementation (n = 52) and placebo groups (n = 50). All parameters were measured before and after treatment. Serum VDBP levels were measured by ELISA method and VDR, GC (VDBP) gene expressions and relative telomere lengths were measured in peripheral blood mononuclear cells (PBMC) using a quantitative real-time PCR method. The results demonstrate that baseline levels were similar between the groups. After vitamin D supplementation 25(OH)D, 1,25(OH)2D, PTH and VDBP levels were changed significantly compared to the placebo group. At the end of the study period, LTL levels were significantly increased in both groups and this change was more prominent in placebo group. The change in GC expression was significant between treatment and placebo groups but VDR expression remained unchanged. Even though the study was designed to solely assess the effects of vitamin D supplementation, LTL was significantly increased in the whole study group in summer months suggesting that LTL levels are affected by sun exposure and seasonal changes rather than supplementation. The study displayed the short-term effect of Vitamin D supplementation on vitamin D, PTH levels, LTL and vitamin D associated gene expressions. The relation between Vitamin D and LTL is not linear and could be confounded by several factors such as the population differences, regional and seasonal changes in sun exposure.

Institutional experience of newborn screening for inborn metabolism disorders by tandem MS in the Turkish population.

Background The tandem mass spectrometry method in the screening of congenital metabolic disorders is not included in routine national newborn screening programmes in Turkey. To evaluate the distribution of acylcarnitines and amino acid levels in normal newborns, establish acylcarnitine and amino acid cut-off levels and further preliminary results of inherited metabolic disorders inferentially in the Turkish population. Methods Newborn screening tests performed by tandem MS from 2016 to 2018 were retrospectively reviewed. The study group included 17,066 newborns born in our hospitals located in various regions of Turkey. Blood samples were obtained from infants older than 24 h of age. Among the 17,066 newborns, the metabolic screening data of 9,994 full-term newborns (>37 weeks) were employed to obtain the percentile distribution of the normal population. The study group (17,066) was screened for 26 types of inborn error of metabolism. Results Our established cut-offs, were compared with the cut-offs determined by Region for Stork Study and Centers for Disease Control. Among the 26 screened disorders, a total of 12 cases (8 amino acid metabolism disorders, 1 urea cycle defect, 2 organic acidaemias and 1 fatty acid oxidation disorder) were identified. Conclusions Because of the high rate of consanguineous marriages in Turkey, the development of a nationwide screening panel is necessary for early detection and management of potentially treatable inherited metabolic disorders.

Glutaric acidemia type II patient with thalassemia minor and novel electron transfer flavoprotein-A gene mutations: A case report and review of literature.

Glutaric acidemia type II (GAII), also known as multiple acyl-CoA dehydrogenase deficiency, is an autosomal recessive inborn error of amino acid and fatty acid metabolism. We report a case of GAII with novel electron transfer flavoprotein (ETF)-A mutations in a 2-year-old female with thalassemia minor. The patient developed an episode of hypoglycemia and hypotonicity on the postnatal first day. Laboratory investigations revealed elevations of multiple acyl carnitines indicating glutaric acidemia type II in newborn screening analysis. Urinary organic acids were evaluated for the confirmation and revealed a high glutaric acid excretion. Genetic analysis revealed two novel mutations in the ETF-A gene, which are considered to be compound heterozygote. At the 8 mo of life ketone therapy was added, which significantly increased the neuromotor development. The patient had been closely followed for two years with carnitine, riboflavin, coenzyme Q10, and ketone supplementation in addition to a high carbohydrate diet. Although the patient had comorbidity like thalassemia minor, her neuromotor development was normal for her age and had no major health problems. This specific case expands the previously reported spectrum of this disease.

Analysis of Changes in Parathyroid Hormone and 25 (OH) Vitamin D Levels with Respect to Age, Gender and Season: A Data Mining Study.

BACKGROUND: 25 (OH) vitamin D3 (25(OH)D) and parathyroid hormone (PTH) are important regulators of calcium homeostasis. The aim of this study was to retrospectively determine the cut-off for sufficient 25(OH)D in a four-season region and the influence of age, seasons, and gender on serum 25(OH)D and PTH levels. METHODS: Laboratory results of 9890 female and 2723 male individuals aged 38.8±22.1 years who had simultaneous measurements of 25(OH)D and PTH were retrospectively analyzed by statistical softwares. Serum 25(OH)D and PTH levels were measured by a mass spectrometry method and by an electrochemiluminescence immunoassay, respectively. RESULTS: Mean serum 25(OH)D levels showed a sinusoidal fluctuation throughout the year and were significantly (p<0.01) higher in summer and autumn. On the other hand, PTH levels were significantly higher (p<0.01) in women and showed an opposite response to seasonal effects relative to 25(OH)D. Lowest levels of 25(OH)D were detected in people aged between 20 and 40 years whereas PTH hormone levels were gradually increasing in response to aging. The significant exponential inverse relationship that was found between PTH and 25(OH)D (PTH=exp(4.12-0.064*sqrt(25(OH)D)) (r=-0.325, R- squared=0.105, p<0.001)) suggested that the cut-off for sufficient 25(OH)D should be 75 nmol/L. CONCLUSIONS: Our retrospective study based on large data set supports the suitability of the currently accepted clinical cut-off of 75 nmol/L for sufficient 25(OH)D. However, the issue of assessing Vitamin D deficiency remains difficult due to seasonal variations in serum 25(OH)D. Therefore, PTH measurements should complement 25(OH)D results for diagnosing Vitamin D deficiency. It is imperative that seasonally different criteria should be considered in future.

Hepatitis C virus positive patient diagnosed after detection of atypical cryoglobulin.

A 60-year-old male patient presented with jaundice and dark urine for three days, icteric sclerae and skin rash on his legs for six months. Laboratory investigations revealed an atypical cryoglobulinemia with high hepatitis C virus (HCV)-RNA levels. Imaging studies showed cholestasis was accompanying HCV. Capillary zone electrophoresis using immunosubtraction method revealed a polyclonal immunoglobulin G and immunoglobulin A (IgA) monoclonal cryoglobulin and that IgA lambda was absent in immunofixation electrophoresis. After a liver biopsy, chronic hepatitis C, HCV related mixed cryoglobulinemia and cryoglobulinemic vasculitis were diagnosed and antiviral therapy was initiated. Our HCV patient presented with cryoglobulinemic symptoms with an atypical cryoglobulinemia that was detected by an alternative method: Immunosubtraction by capillary electrophoresis. Different types of cryoglobulins may therefore have a correlation with clinical symptoms and prognosis. Therefore, the accurate immunotyping of cryoglobulins with alternative methods may provide more information about cryoglobulin-generated pathology.

A triclonal gammopathy in a relapsing multiple myeloma patient, detected by immunosubtraction method.

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the malignant proliferation of a plasma cell clone that produces a monoclonal immunoglobulin. Diagnosis and management of patients with monoclonal gammopathies depend on accurate identification and characterization of monoclonal proteins. We present a 67-year-old male patient with anaemia, weakness and weight loss for six months. His physical examination was normal with no fever, and no bone lesions were present in the imaging studies. Laboratory investigations revealed low haemoglobin and albumin concentrations with high total protein and beta 2-microglobulin concentrations. Capillary zone electrophoresis with immunosubtraction method revealed a triclonal pattern of M-protein (IgG κ + IgG λ + IgA κ) which was not prominent with immunofixation electrophoresis. After bone marrow biopsy, MM with triclonal gammopathy was diagnosed and autologous stem cell transplantation was performed. Six months later, again a triclonal M-protein was detected by immunosubtraction method, and a relapse was confirmed with a second bone marrow biopsy. The occurrence of monoclonal and biclonal gammopathies can often be seen upon diagnosis in plasma cell dyscrasias and lymphoproliferative disorders, but triclonal paraproteins are very rare and their clinical significance is unknown. In this particular patient, triclonality was detected by an alternative method called immunosubtraction by capillary electrophoresis. The patient was resistant to therapy suggesting that more than one monoclonal M protein may be a negative prognostic factor, and with new technologies and methods, the number of patients with different monoclonal patterns may increase.

Voice and speech changes in various phases of menstrual cycle.

BACKGROUND: The reproductive system in females undergoes a regular cyclic change known as the menstrual cycle. Laryngeal changes are evident and fluctuate systematically during the reproductive years with the menstrual cycle. The impact of estrogens in concert with progesterone produces the characteristics of the female voice, with a fundamental frequency (F(0)) higher than that of male. OBJECTIVE: To characterize changes in voice and speech in adolescent females in different phases of the menstrual cycle--during menstruation, after menstruation, mid-menstrual cycle, and premenstruation. MATERIALS AND METHODS: Sixteen adult females who were nonusers of oral contraceptives participated in a cross-sectional study of menstrual cycle influences on voicing and speaking tasks. Acoustic analysis (F(0), intensity, perturbation measurements [jitter and shimmer], and harmonic-to-noise ratio), maximum phonation time (MPT), s/z ratio, and perceptual assessments (grade [G], roughness [R], breathiness [B], asthenia [A], and strain [S] [GRBAS] and Voice Handicap Index-10 [VHI-10]) scales were performed during all phases. RESULTS: None of the acoustic analysis parameters and MPT and s/z ratio measurements revealed statistically significant difference (P > 0.05). Perceptual voice assessment scales either clinician based or patients self-evaluated showed significant differences among phases (P < 0.05). CONCLUSIONS: The objective voice analysis methods, such as acoustic analysis, MPT, and s/z ratio, determined no difference; however, the subjective voice analysis methods, such as clinician-based perceptual assessment (GRBAS) and patients self-evaluation (VHI-10) scales, demonstrated significant changes during different phases of menstrual cycle.

The protective effects of spirulina in cyclophosphamide induced nephrotoxicity and urotoxicity in rats.

OBJECTIVE: To evaluate the role of Spirulina, a blue-green algae with antioxidant properties in the protection of cyclophosphamide-induced nephrotoxicity and hemorrhagic cystitis in rats. METHODS: The control group (C) was sacrificed 24 hours after being given a single dose of saline intraperitoneally (150 mg/kg) on the seventh day of the experiment. The rats in the second group (CP) were sacrificed 24 hours after being given a single dose of cyclophosphamide, intraperitoneally (150 mg/kg) on the seventh day of the experiment. Spirulina was administered to the third group (SP+CP) orally (1000 mg/kg bw/day) for 7 days and a single dose of cyclophosphamide was injected intraperitoneally (150 mg/kg) on the seventh day of the experiment. At the eighth day of the experiment, malondialdehyde, superoxide dismutase, and catalase levels in renal and urinary bladder tissues were measured. Histomorphology in urinary bladder, apoptosis by caspase 3 immunostaining, and TUNEL assay in kidney were also evaluated. RESULTS: Tissue levels of malondialdehyde in the SP+CP group were significantly lower versus CP group (P < .05). Tissue levels of superoxide dismutase and catalase in the SP+CP group were significantly higher vs the CP group (P < .05). The histomorphologic alteration in urinary bladder in the SP+CP group was significantly lower vs that in the CP group. In the kidney, apoptosis in the SP+CP group as shown with TUNEL assay and immunohistochemistry was significantly lower vs that in the CP group (P < .05). CONCLUSION: Pretreatment with Spirulina protects the rats from cyclophosphamide-induced nephro-urotoxicity via its antioxidant and anti-apoptotic properties.

Melatonin with 1,25-dihydroxyvitamin D3 protects against apoptotic ischemia-reperfusion injury in the rat kidney.

This study was designed to evaluate the preventive role of melatonin (Mel) and 1,25-dihydroxyvitamin D3 (VD3) in biochemical and apoptotic events leading to tissue injury and renal dysfunction after ischemia-reperfusion (I/R). Thirty male Wistar rats were divided into five groups: sham-operated, I/R, Mel + I/R, VD3 + I/R, and Mel + VD3 + I/R. The rats were intraperitoneally administered with Mel (10 mg/kg), VD3 (0.5 µg/kg), or Mel (10 mg/kg) plus VD3 (0.5 µg/kg) each day at 1 week prior to ischemia. Right nephrectomy was initially performed and left renal I/R injury was induced by 45 min of bilateral renal ischemia followed by 45 min of reperfusion. After reperfusion, kidneys and blood were obtained for histopathologic and biochemical evaluation. Mel and VD3 had an ameliorative effect on biochemical parameters such as serum creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, and apoptosis (caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining) in the kidneys against renal I/R injury in rats. Additionally, VD3 combined with Mel significantly reduced apoptotic and histological alterations when compared with Mel or VD3 alone. This preventive effect on renal tubular apoptosis was remarkable when Mel was combined with VD3.

Bone turnover and maternal 25(OH) vitamin D3 levels during pregnancy and the postpartum period: should routine vitamin D supplementation be increased in pregnant women?

OBJECTIVE: To investigate the relationship between 25(OH) vitamin D3 levels and maternal bone turnover during pregnancy and lactation. STUDY DESIGN: Thirty pregnant women and 30 healthy non-pregnant controls were included the study. The pregnant women were examined in the 12th, 25th and 32nd gestational weeks and 6 weeks after delivery. The controls were examined once. Serum concentrations of 25(OH) vitamin D3, parathyroid hormone (PTH), cross-linked C-terminal telopeptide of type I collagen (CTX), calcium, and phosphate were measured. RESULTS: In the 32nd week and the postpartum period, 25(OH) vitamin D3 deficiency rates were 13.3% and 33.3%, respectively. Serum 25(OH) vitamin D3 levels were below the detection limit in 10% and 33%, respectively, of the same subjects. In the control group, rates of 25(OH) vitamin D3 deficiency and "below detection limit" were 30% and 23%, respectively. While 25(OH) vitamin D3 and CTX levels were not correlated to each other in the first trimester, a negative correlation was found in the 2nd and 3rd trimesters and the postpartum period between 25(OH) vitamin D3 and CTX levels (r=-0.472, p=0.048; r=-0.893, p<0.0001, r=-0.881, p<0.001, respectively). No correlation between 25(OH) vitamin D3 and CTX levels was found in controls. CONCLUSION: We consider that 25(OH) vitamin D3 supplementation of women could both decrease maternal bone resorption and lead to enhanced bone mass in offspring during later life. Since women are prone to 25(OH) vitamin D3 insufficiency, we suggest higher doses of 25(OH) vitamin D3 should be given to pregnant subjects.

Negative correlation between D-dimer and homocysteine levels during pregnancy and the postpartum period: a prospective study.

OBJECTIVE: There have been conflicting data about the role of increased levels of homocysteine (Hcy) on haemostatic system. We aim to investigate prospectively the relation between serum Hcy levels and changes in haemostatic system in pregnancy and postpartum period. STUDY DESIGN: Sixty-eight healthy pregnant women were included in the study. Blood samples were obtained in the 11th gestational week, 25th gestational week, 32nd gestational week and postpartum 4th week. The haemoglobin levels, white blood cell count (WBC), platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, D-dimer, Hcy, vitamin B12, and folate levels were measured. RESULTS: Serum Hcy levels were negatively correlated with D-dimer levels (r = -0.57, p < 0.0001). The highest levels of D-dimer (1046.62 ± 322.01 ng/ml) were achieved in the third trimester and the lowest levels of serum Hcy (4.45 ± 1.23 mmol/l) were detected in the same trimester. In postpartum fourth week, D-dimer levels were decreased to normal levels (238.27 ± 198.59 ng/ml) while the serum Hcy levels were reached to the highest levels (7.99 ± 1.36 mmol/l). CONCLUSION: The negative correlation between Hcy and D-dimer levels may be a compensatory mechanism to maintain the normal haemostatic balance in pregnancy. Hence, possible advantage of low Hcy levels in pregnancy may be to prevent undesired thrombosis.

Relationship between bone mineral density, bone turnover markers and homocysteine, folate and vitamin B12 levels in postmenopausal women.

PURPOSE: We aimed to investigate whether levels of homocysteine (Hcy), folate, and vitamin B12 are related to bone turnover markers and bone mineral density (BMD) in postmenopausal women. METHODS: One hundred and twenty postmenopausal women were divided into three groups: osteoporotic, osteopenic and normal, according to the BMD measurements. The age, weight, body mass index (BMI), years since menopause (YSM), gravidity, parity, bone turnover markers [type I collagen C-telopeptides (CTx) and bone-specific alkaline phosphatase (BAP)], serum Hcy, parathyroid hormone (PTH), vitamin B12, folate, calcium and magnesium levels were compared with each other. RESULTS: Twenty-five women had osteoporotic, 42 women had osteopenic, and 53 had normal BMD values. After adjusting for confounding factors, serum Hcy levels were significantly higher in osteoporotic women [adj OR = 38.95 (1.474-1029.88) p = 0.02]. The age, YSM, PTH, CTx and BAP levels were related to serum Hcy in all women (beta = 0.523, p = 0.0001; beta = 0.446, p = 0.001; beta = 0.295, p = 0.005; beta = 0.239, p = 0.026; beta = 0.451, p = 0.001, respectively). CONCLUSIONS: Our data showed that vitamin B12, folate and Hcy levels were not related with BMD in postmenopausal women. We think that one of the underlying mechanisms of increased Hcy levels and osteoporosis may be a mechanistic link which cannot detected by BMD or biochemical markers.

Homocysteine levels and echocardiographic findings in obstructive sleep apnea syndrome.

BACKGROUND: The obstructive sleep apnea syndrome (OSAS) is characterized by repeated upper airway obstruction during sleep together with decreases in oxygen saturation leading to a series of pathological events, primarily in the cardiovascular system. Elevated plasma homocysteine levels have recently been considered as an independent risk factor for vascular disease, and increased levels are attributed to cardiovascular diseases. OBJECTIVES: We aimed to investigate the possible relationship between homocysteine levels and echocardiographic findings in OSAS patients at different stages of disease. METHODS: Thirty-eight patients (23 males and 15 females) with polysomnographically verified OSAS (mean age, 49 +/- 12 years, range 27-74) and a mean body mass index of 31.27 +/- 5.24 kg/m(2) (range 22.60-47.90) were prospectively studied. Plasma levels of homocysteine, cholesterols, triglycerides, vitamin B(12) and high-sensitive C-reactive protein (hsCRP), as well as echocardiographic and lung function parameters were assessed. RESULTS: Homocysteine levels were elevated in all OSAS groups and were statistically significantly different between the mild and moderate/severe groups. Significant differences were present between the variables nocturnal oxygen desaturation (NOD), respiratory arousal and light sleep among the mild and moderate/severe groups. We found a significant positive correlation between homocysteine levels and NOD duration, and hsCRP levels were positively correlated with the apnea-hypopnea index and NOD duration. CONCLUSIONS: In all OSAS groups, homocysteine levels were elevated regardless of the presence of cardiac dysfunction. Echocardiographic abnormalities were primarily left-ventricular (LV) hypertrophy and LV diastolic dysfunction and could be observed in all OSAS severity groups.

The effect of vitamin C on ischemia reperfusion injury because of prolonged tourniquet application with reperfusion intervals.

We examined the effect of vitamin C on muscle injury distal to the tourniquet which was applied for 4 hours with 10- and 20-minute reperfusion intervals after 2 hours of tourniquet. Sixty-four Sprague-Dawley rats were allocated to 4 randomized groups. After 2 hours tourniquet, 10- and 20-minutes of reperfusion were allowed to half of each group respectively. Afterward an additional 2 hours compression was applied. Except the control group the animals received vitamin C intravenously, before the first tourniquet in Group I, at the reperfusion interval in Group II, and at both times in Group III. Malondialdehyde levels were measured in blood and the tibialis anterior muscle. The muscle was histopathologically examined. The data was evaluated statistically. The effects of timing and the dose of vitamin C on ischemia reperfusion injury remain controversial and there was no statistical difference between 10- and 20-minute reperfusion intervals. But the blood malondialdehyde levels showed that vitamin C has a positive effect on the muscle injury caused by ischemia-reperfusion.

Is there any relationship between streptococcal infection and multiple sclerosis?

BACKGROUND: Multiple sclerosis (MS) is an immune-mediated inflammatory demyelinating disease of uncertain etiology. Although the mechanisms of inducting autoimmunity by some of the infectious agents have been investigated, there is not yet enough research on streptococcal infections. MATERIAL/METHODS: To understand the effect of past group A streptococcal infection on MS, antistreptolysin O (ASO) and antideoxyribonuclease B (ADNase B) were measured in 21 patients with relapsing-remitting MS and 21 healthy blood donors by nephelometric assay. RESULTS: ADNase B levels in the patients with MS were found to be significantly higher than in the controls (p<0.001); however, ASO levels were similar in both groups. CONCLUSIONS: These findings indicate that a relationship between multiple sclerosis and streptococcal infections may exist, but to acquire a better understanding of the role of group A streptococci in the pathogenesis of multiple sclerosis, more studies with animal models are necessary.

Nitric oxide, endothelin-1, and superoxide production in arterial bypass grafts.

In this study, basal and thrombin-stimulated release of nitric oxide and endothelin-1 in the internal mammary artery and the radial artery were measured, together with superoxide radicals generated after anoxia and reoxygenation. Arterial segments were obtained from patients undergoing coronary bypass operations. Quantification of nitric oxide was performed by measuring the stable oxidation products of nitric oxide. Endothelin levels were measured by an enzyme immunoassay kit, and the superoxides were measured by lucigenin-enhanced chemiluminescence. Basal and stimulated release of nitric oxide from the internal mammary artery is significantly higher than that in the radial artery. On the other hand, basal release of endothelin-1 is less in the internal mammary artery than in the radial artery, but similar after stimulation. In our study, the quantity of superoxide radicals produced by the internal mammary artery was greater than that produced by the radial artery. Our results show that there are differences between these 2 arteries in regard to production of nitric oxide, endothelin-1, and superoxide radicals. These differences may have a role in the process of atherogenesis and may contribute to long-term patency of arterial bypass grafts. These results may also explain the mechanism of radial artery graft spasm in coronary artery surgery and may constitute a basis for future pharmacological and clinical improvements for successful surgical application.

Effects of intermittent fasting on serum lipid levels, coagulation status and plasma homocysteine levels.

BACKGROUND: During Ramadan, Muslims fast during the daylight hours for a month. The duration of restricted food and beverage intake is approximately 12 h/day which makes Ramadan a unique model of intermittent fasting. Many physiological and psychological changes are observed during Ramadan that are probably due to the changes in eating and sleeping patterns. METHODS: Serum total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), prothrombin time, activated partial thromboplastin time (aPTT), plasma fibrinogen, D-dimer and homocysteine levels were measured in 24 healthy fasting volunteers (12 females, 12 males) aged 21-35 years. Venous blood samples were taken 1 week before Ramadan, on the 21st day of Ramadan and 20 days after Ramadan. RESULTS: No significant changes were observed on serum total cholesterol, triglycerides and LDL levels. HDL levels were significantly elevated during Ramadan (p < 0.001) and 20 days after Ramadan (p < 0.05). Prothrombin time, aPTT, fibrinogen and D-dimer levels were in the physiologic limits in all samples but D-dimer levels were significantly low at the end of Ramadan in comparison to pre- and post-fasting levels (p < 0.001). Homocysteine levels, being still in reference ranges, were low during Ramadan (p < 0.05) and reached the pre-fasting levels after Ramadan. CONCLUSION: Our results demonstrate that intermittent fasting led to some beneficial changes in serum HDL and plasma homocysteine levels, and the coagulation status. These changes may be due to omitting at least one meal when the body was particularly metabolically active and possibly had a low blood viscosity level at the same time. We conclude that intermittent fasting may have beneficial effects on hemostatic risk markers for cardiovascular diseases.