Fahr Syndrome - an Important Piece of a Puzzle in the Differential Diagnosis of Many Diseases.

Fahr syndrome is a rare neurodegenerative disorder characterized by symmetrical, bilateral calcifications in the basal ganglia, nucleus gyrus and cerebral cortex. The continuous advancement as well as widespread use of brain imaging have contributed to the increasing detection rates of such changes. Nevertheless, their etiology is understood only partially and the methods of causative treatment are limited. Due to various symptoms, Fahr syndrome may resemble diseases from the field of neurology, psychiatry, cardiology and even urology. This article provides an up-to-date review of the literature concerning Fahr syndrome in terms of clinical practice.

Radiological Evaluation of Strategic Structures in Patients with Mild Cognitive Impairment and Early Alzheimer's Disease.

BACKGROUND: The aim of the study was to evaluate the diagnostic value of two measurement techniques in patients with cognitive impairment - automated volumetry of the hippocampus, entorhinal cortex, parahippocampal gyrus, posterior cingulate gyrus, cortex of the temporal lobes and corpus callosum, and fractional anisotropy (FA) index measurement of the corpus callosum using diffusion tensor imaging. MATERIAL/METHODS: A total number of 96 patients underwent magnetic resonance imaging study of the brain - 33 healthy controls (HC), 33 patients with diagnosed mild cognitive impairment (MCI) and 30 patients with Alzheimer's disease (AD) in early stage. The severity of the dementia was evaluated with neuropsychological test battery. The volumetric measurements were performed automatically using FreeSurfer imaging software. The measurements of FA index were performed manually using ROI (region of interest) tool. RESULTS: The volumetric measurement of the temporal lobe cortex had the highest correct classification rate (68.7%), whereas the lowest was achieved with FA index measurement of the corpus callosum (51%). The highest sensitivity and specificity in discriminating between the patients with MCI vs. early AD was achieved with the volumetric measurement of the corpus callosum - the values were 73% and 71%, respectively, and the correct classification rate was 72%. The highest sensitivity and specificity in discriminating between HC and the patients with early AD was achieved with the volumetric measurement of the entorhinal cortex - the values were 94% and 100%, respectively, and the correct classification rate was 97%. The highest sensitivity and specificity in discriminating between HC and the patients with MCI was achieved with the volumetric measurement of the temporal lobe cortex - the values were 90% and 93%, respectively, and the correct classification rate was 92%. CONCLUSIONS: The diagnostic value varied depending on the measurement technique. The volumetric measurement of the atrophy proved to be the best imaging biomarker, which allowed the distinction between the groups of patients. The volumetric assessment of the corpus callosum proved to be a useful tool in discriminating between the patients with MCI vs. early AD.

Predicting the conversion of mild cognitive impairment to Alzheimer's disease based on the volumetric measurements of the selected brain structures in magnetic resonance imaging.

INTRODUCTION: Mild cognitive impairment (MCI) is defined as abnormal cognitive state, but does not meet the criteria for the diagnosis of dementia. According to the new guidelines Alzheimer's disease (AD) involves not only dementia's phase but also predementia phase which is asymptomatic and pathological process in the brain is already present. For this reason it is very important to determine the suitability of markers which should be positive before onset of the first symptoms. One of these biomarkers is a structural magnetic resonance imaging with hippocampal volumetric assessment. The aim of this study was to investigate the usefulness of structural brain magnetic resonance imaging with volumetric assessment of the hippocampus and entorhinal cortex, posterior cingulate gyrus, parahippocampal gyrus, temporal gyri: superior, medial and inferior, to predict the conversion of MCI to AD. MATERIAL AND METHODS: Magnetic resonance imaging of brain was performed at the baseline visit in 101 patients diagnosed with MCI. Clinic follow-ups were scheduled after 6.12 and 24 months. RESULTS: Amongst 101 patients with MCI, 17 (16.8%) converted into AD within two years of observation. All measured volumes were lower in converters than non-converters. Discriminant analysis was conducted and sensitivity for MCI conversion to AD was 64.7%, specificity 96.4%. 91% of patients were correctly classified (converter or non-converter). CONCLUSIONS: Volumetric measurements may help clinicians to predict MCI conversion to AD but due to low sensitivity it cannot be use separately. The study group requires further observation.

Analysis of calcium homeostasis in fresh lymphocytes from patients with sporadic Alzheimer's disease or mild cognitive impairment.

Alzheimer's disease (AD) is the most widespread, age-related neurodegenerative disorder. Its two subtypes are sporadic AD (SAD) of unknown etiology and genetically encoded familial AD (FAD). The onset of AD is often preceded by mild cognitive impairment (MCI). Calcium dynamics were found to be dysregulated in FAD models, but little is known about the features of calcium dynamics in SAD. To explore calcium homeostasis during the early stages of SAD, we investigated store-operated calcium entry (SOCE) and inositol triphosphate receptor (IP3R)-mediated calcium release into the cytoplasm in unmodified B lymphocytes from MCI and SAD patients and compared them with non-demented subjects (NDS). Calcium levels in the endoplasmic reticulum and both the rising and falling SOCE slopes were very similar in all three groups. However, we found that SAD and MCI cells were more prone to IP3R activation than NDS cells, and increases in calcium levels in the cytoplasm were almost twice as frequent in SAD cells than in NDS cells. MCI cells and SAD cells exhibited an enhanced magnitude of calcium influx during SOCE. MCI cells but not SAD cells were characterized by higher basal cellular calcium levels than NDS cells. In summary, perturbed calcium homeostasis was observed in peripheral cells from MCI and SAD patients. Thus, lymphocytes obtained from MCI subjects may be promising in the early diagnosis of individuals who will eventually develop SAD. However, no conclusions are made regarding SAD due to the limited number patients. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.

Polymorphisms of paraoxonase 1 and 2 genes and the risk of multiple sclerosis in the Polish population.

BACKGROUND AND PURPOSE: The aim of this study was to test the hypothesis that polymorphisms of the paraoxonase genes PON1 and PON2 may be associated with increased risk of developing multiple sclerosis (MS) in the Polish population. MATERIAL AND METHODS: We studied the significance of the PON gene polymorphisms C311S, A162G, Q192R and L55M in 221 patients (including 145 women) with MS and in 661 healthy controls. In the MS population, mean Expanded Disability Status Scale score was 2.92, mean age was 36.8 years, and mean disease duration was 7.7 years. PON genotyping was determined using polymerase chain reaction and restriction enzyme digestion. RESULTS: According to our results, the PON1 and PON2 genotypes distribution did not differ between the MS patients and the controls. CONCLUSIONS: The polymorphisms of the PON genes studied are not related to increased risk of MS in the Polish population.

Interleukin-6 gene (-174 C/G ) and apolipoprotein E gene polymorphisms and the risk of Alzheimer disease in a Polish population.

BACKGROUND AND PURPOSE: Inflammation plays a prominent role in Alzheimer disease (AD) pathogenesis. Interleukin-6 (IL-6), a pro-inflammatory cytokine, and some genetic variations in the IL-6 gene have been reported to be associated with a risk of AD. However, the results of the conducted studies are equivocal. MATERIAL AND METHODS: We genotyped IL-6 (-174 C/G) and apolipoprotein E gene (APOE) common polymorphisms in a large case-controlled study in a Polish population. We included 361 patients aged ≥ 65 years with AD (mean age 75.8 ± 5.3 years, 232 females [64.3%]) and 200 controls (75.3 ± 7.4 years; 119 females [59.5%]), without any neurological deficit, cognitive complaints or history of neurological diseases. The IL-6 polymorphism was genotyped using TaqMan SNP allelic discrimination by means of an ABI 7900HT (Applied Biosystems, Foster City, CA). RESULTS: The distribution of the IL-6 (-174 C/G) genotypes was similar to that in the controls (AD: C/C = 15.79%, C/G = 51.25%, G/G = 32.96% vs. controls: C/C = 21.50%, C/G = 45.50%, G/G = 33.0%, p > 0.05). Our study confirms previous reports that APOE 4 is strongly related to the risk of AD (OR = 6.17; 95% CI: 4.01-9.49). APOE status did not affect the distribution of the studied IL-6 polymorphism. CONCLUSION: IL-6 (-174 C/G) polymorphism is not a risk factor for late onset AD in a Polish population.

PIN1 gene variants in Alzheimer's disease.

BACKGROUND: Peptidyl-prolyl isomerase, NIMA-interacting 1 (PIN1) plays a significant role in the brain and is implicated in numerous cellular processes related to Alzheimer's disease (AD) and other neurodegenerative conditions. There are confounding results concerning PIN1 activity in AD brains. Also PIN1 genetic variation was inconsistently associated with AD risk. METHODS: We performed analysis of coding and promoter regions of PIN1 in early- and late-onset AD and frontotemporal dementia (FTD) patients in comparison with healthy controls. RESULTS: Analysis of eighteen PIN1 common polymorphisms and their haplotypes in EOAD, LOAD and FTD individuals in comparison with the control group did not reveal their contribution to disease risk.In six unrelated familial AD patients four novel PIN1 sequence variants were detected. c.58+64C>T substitution that was identified in three patients, was located in an alternative exon. In silico analysis suggested that this variant highly increases a potential affinity for a splicing factor and introduces two intronic splicing enhancers. In the peripheral leukocytes of one living patient carrying the variant, a 2.82 fold decrease in PIN1 expression was observed. CONCLUSION: Our data does not support the role of PIN1 common polymorphisms as AD risk factor. However, we suggest that the identified rare sequence variants could be directly connected with AD pathology, influencing PIN1 splicing and/or expression.

Variation in NPC1, the gene encoding Niemann-Pick C1, a protein involved in intracellular cholesterol transport, is associated with Alzheimer disease and/or aging in the Polish population.

There is abundant evidence that cholesterol metabolism, especially as mediated by the intercellular transporter APOE, is involved in the pathogenesis of sporadic, late-onset Alzheimer disease (SLAD). Identification of other genes involved in SLAD pathogenesis has been hampered since gene association studies, whether individual or genome-wide, experience difficulty in finding appropriate controls in as much as 25% or more of normal adults will develop SLAD. Using 152 centenarians as additional controls and 120 "regular", 65-75-year-old controls, we show an association of genetic variation in NPC1 with SLAD and/or aging. In this preliminary study, we find gradients of two non-synonymous SNP's allele frequencies in NPC1 from centenarians through normal controls to SLAD in this non-stratified Polish population. An intervening intronic SNP is not in Hardy-Weinberg equilibria and differs between centenarians and controls/SLAD. Haplotypes frequencies determined by fastPHASE were somewhat different, and the predicted genotype frequencies were very different between the three groups. These findings can also be interpreted as indicating a role for NPC1 in aging, a role also suggested by NPC1's role in Dauer formation (hibernation, a longevity state) in Caenorhabditis elegans.

Analysis of APBB2 gene polymorphisms in sporadic Alzheimer's disease.

The accumulation of beta-amyloid (Abeta) in the brain plays a central role in the pathogenesis of Alzheimer's disease (AD). The processing of Abeta precursor protein to Abeta is modulated by binding proteins including APBB2 [amyloid beta precursor protein-binding family B member 2, FE65-like, FE65L1]. We investigated two intronic SNPs within the APBB2 gene: rs13133980 and hCV1558625 (rs17443013), among Polish AD patients and healthy controls (n=213, 171). The frequencies of rs13133980 alleles and genotypes did not differ between cases and controls, irrespective of age of onset or APOE epsilon4 carrier status. The hCV1558625 G allele was over-represented in patients with onset under age 70 compared to controls in the same age range (57% vs. 43%, p=0.03). The association between the hCV1558625 G allele and susceptibility for AD at relatively young ages needs to be confirmed in other samples.

Analysis of UBQLN1 variants in a Polish Alzheimer's disease patient: control series.

Late-onset Alzheimer's disease (LOAD) is the most common neurodegenerative disorder, and has a complex etiology. Recently an intronic polymorphism in the ubiquilin 1 gene (UBQLN1) and a particular haplotype was reported to be associated with LOAD. We investigated whether variants in UBQLN1 confer a risk for the disease in 407 Polish LOAD patients and 407 controls. We observed a weak association with the rs2781002 polymorphism, however, contrary to the initial reports, in our group the association was with the A allele. Risk estimation for AA versus GG genotypes showed that the AA genotype is a weak risk factor for AD (OR = 1.8, 95% CI = 1.1-3.1, p = 0.025). This effect was stronger in a group of LOAD patients without APOE4 allele. Haplotype analyses indicate that there is an increase of haplotypes with an A allele in the case group. Also, the specific haplotypes with the A allele that increase AD risk differ between the APOE4-positive and APOE4-negative pools. However, the association observed seems to be driven mostly by rare (<5%) haplotypes. Results suggest a need for additional association studies and in silico analysis of the UBQLN1 locus.

Association between genetic and environmental factors and the risk of Alzheimer's disease.

The only well confirmed genetic risk factor for sporadic Alzheimer's disease (AD) is the possession of apolipoprotein E (APOE) epsilon4 allele. As it contributes to 40-70% of AD cases, a large proportion of genetic variance may be determined by additional loci. Our aim was to estimate how reported genetic factors (APOE, NOS3, MTHFR) interact to increase the risk for AD and combine them with environmental factors (homocysteine, vitamin B12, cholesterol). Genotyping was performed in 154 AD patients and 176 healthy controls. Levels of homocysteine, vitamin B12 and cholesterol were assessed in subgroups of 100 AD patients and 100 controls. We found a difference in APOE epsilon4 and NOS3 G/G distribution between groups (p<0.005). Plasma total homocysteine was increased and vitamin B12 decreased in AD patients (p<0.001). The influence of APOE epsilon4 and NOS3 G alleles on the risk of AD was independent of homocysteine, vitamin B12 levels and MTHFR status.

Regulatory region single nucleotide polymorphisms of the apolipoprotein E gene as risk factors for Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by a complex aetiology. The ε4 allel of the apolipoprotein E gene (APOE) is the only confirmed genetic risk factor for the development of AD. In addition, polymorphisms at the promoter region of the APOE gene are assumed to modulate the susceptibility to AD by their different affinity to the transcription factors thus affecting the expression of the gene. In the presented study, we investigated the association between -491 A/T (rs449647), -427C/T, (rs769446) and -219 T/G (rs405509) single nucleotide polymorphisms (SNPs) of APOE gene and AD risk in the Polish population. We found that only the -491 T allele and -491 A/T genotype acted as protective factors against AD, whereas the -219 T/G heterozygosity increased risk for AD in APOE ε4 carriers but not in APOE ε4 non-carriers. What is more, haplotype frequency estimation showed significant positive for A-T-T-C-C and A-T-G-C-C haplotypes or negative for A-T-T-T-C and T-T-T-T-C haplotypes associations with AD. These results contribute to the evidence that APOE promoter polymorphisms modulate risk for AD.

Plasma adiponectin array in women with Alzheimer's disease.

Introduction Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease. Typical features of AD include memory loss, social dysfunction and physical impairment. Although the pathological findings in the central nervous system are well established, the etiological factors are poorly known. Recent studies suggested the role of metabolic disturbances in the development of AD neurodegeneration. Adiponectin, an anti-inflammatory and metabolism regulating factor, was linked to AD. Aim The aim was to examine whether adiponectin fractions combined with insulin/insulin resistance-associated metabolic parameters correlate with AD progression. Material and methods The study comprised 98 women: 27 with moderate to severe AD, 31 with AD at early stage and 40 healthy controls, matched for age and BMI. To evaluate memory impairment, the MMSE was performed. Plasma total adiponectin and its high-, medium- and low molecular weights were measured with ELISA. Anthropometric, clinical and metabolic parameters were assessed. Correlations between adiponectin array and measured parameters were evaluated. Results In comparison to the controls, enhanced levels of total and medium molecular weight adiponectin characterized AD individuals. In AD, we found correlations between adiponectin array, and anthropometric and biochemical parameters. After adjustment to BMI, a significant increase of the total adiponectin and high- and medium molecular weight fractions was observed. A negative correlation between low molecular weight adiponectin and MMSE was found. Conclusions Our results indicate a possible link between adiponectin variations and AD. We hypothesize that changes in adiponectin profile observed in AD result from compensatory mechanism against neuropathological processes, as well as from adiponectin homeostasis impairment.

Hypermethylation of TRIM59 and KLF14 Influences Cell Death Signaling in Familial Alzheimer's Disease.

Epigenetic mechanisms play an important role in the development and progression of various neurodegenerative diseases. Abnormal methylation of numerous genes responsible for regulation of transcription, DNA replication, and apoptosis has been linked to Alzheimer's disease (AD) pathology. We have recently performed whole transcriptome profiling of familial early-onset Alzheimer's disease (fEOAD) patient-derived fibroblasts. On this basis, we demonstrated a strong dysregulation of cell cycle checkpoints and DNA damage response (DDR) in both fibroblasts and reprogrammed neurons. Here, we show that the aging-correlated hypermethylation of KLF14 and TRIM59 genes associates with abnormalities in DNA repair and cell cycle control in fEOAD. Based on the resulting transcriptome networks, we found that the hypermethylation of KLF14 might be associated with epigenetic regulation of the chromatin organization and mRNA processing followed by hypermethylation of TRIM59 likely associated with the G2/M cell cycle phase and p53 role in DNA repair with BRCA1 protein as the key player. We propose that the hypermethylation of KLF14 could constitute a superior epigenetic mechanism for TRIM59 hypermethylation. The methylation status of both genes affects genome stability and might contribute to proapoptotic signaling in AD. Since this study combines data obtained from various tissues from AD patients, it reinforces the view that the genetic methylation status in the blood may be a valuable predictor of molecular processes occurring in affected tissues. Further research is necessary to define a detailed role of TRIM59 and KLF4 in neurodegeneration of neurons.

Overactive BRCA1 Affects Presenilin 1 in Induced Pluripotent Stem Cell-Derived Neurons in Alzheimer's Disease.

The BRCA1 protein, one of the major players responsible for DNA damage response has recently been linked to Alzheimer's disease (AD). Using primary fibroblasts and neurons reprogrammed from induced pluripotent stem cells (iPSC) derived from familial AD (FAD) patients, we studied the role of the BRCA1 protein underlying molecular neurodegeneration. By whole-transcriptome approach, we have found wide range of disturbances in cell cycle and DNA damage response in FAD fibroblasts. This was manifested by significantly increased content of BRCA1 phosphorylated on Ser1524 and abnormal ubiquitination and subcellular distribution of presenilin 1 (PS1). Accordingly, the iPSC-derived FAD neurons showed increased content of BRCA1(Ser1524) colocalized with degraded PS1, accompanied by an enhanced immunostaining pattern of amyloid-ß. Finally, overactivation of BRCA1 was followed by an increased content of Cdc25C phosphorylated on Ser216, likely triggering cell cycle re-entry in FAD neurons. This study suggests that overactivated BRCA1 could both influence PS1 turnover leading to amyloid-ß pathology and promote cell cycle re-entry-driven cell death of postmitotic neurons in AD.

Combined use of biochemical and volumetric biomarkers to assess the risk of conversion of mild cognitive impairment to Alzheimer's disease.

INTRODUCTION: The aim of our study was to evaluate the usefulness of several biomarkers in predicting the conversion of mild cognitive impairment (MCI) to Alzheimer's disease (AD): ß-amyloid and tau proteins in cerebrospinal fluid and the volumetric evaluation of brain structures including the hippocampus in magnetic resonance imaging (MRI). MATERIAL AND METHODS: MRI of the brain with the volumetric assessment of hippocampus, entorhinal cortex, posterior cingulate gyrus, parahippocampal gyrus, superior, medial and inferior temporal gyri was performed in 40 patients diagnosed with mild cognitive impairment. Each patient had a lumbar puncture to evaluate ß-amyloid and tau protein (total and phosphorylated) levels in the cerebrospinal fluid. The observation period was 2 years. RESULTS: Amongst 40 patients with MCI, 9 (22.5%) converted to AD within 2 years of observation. Discriminant analysis was conducted and sensitivity for MCI conversion to AD on the basis of volumetric measurements was 88.9% and specificity 90.3%; on the basis of ß-amyloid and total tau, sensitivity was 77.8% and specificity 83.9%. The combined use of the results of volumetric measurements with the results of proteins in the cerebrospinal fluid did not increase the sensitivity (88.9%) but increased specificity to 96.8% and the percentage of correct classification to 95%.

Association between Cerebrospinal Fluid Biomarkers for Alzheimer's Disease, APOE Genotypes and Auditory Verbal Learning Task in Subjective Cognitive Decline, Mild Cognitive Impairment, and Alzheimer's Disease.

In the course of Alzheimer's disease (AD), early pathological changes in the brain start decades before any clinical manifestation. The concentration levels of AD cerebrospinal fluid (CSF) biomarkers, such as amyloid-ß1-42 (Aß1-42), total tau (T-tau), and phosphorylated tau (P-tau), may reflect a cerebral pathology facilitating an early diagnosis of the disease and predicting a cognitive deterioration. The aim of this study was to estimate the prevalence of AD CSF biomarkers in those individuals with a subjective cognitive decline (SCD), a mild cognitive impairment (MCI), and Alzheimer's dementia (AD-D), together with the relationships between the biomarkers, an APOE ɛ4 presence, and a verbal episodic memory performance. We included 252 patients from the memory clinic with a diagnosis of SCD (n = 85), MCI (n = 87), and AD-D (n = 80). A verbal episodic memory performance level was assessed and was based on a delayed recall trial from the 10-word list of an auditory verbal learning task (AVLT). We found that the patients with more severe cognitive impairments had significantly lower levels of Aß1-42 and higher levels of T-tau and P-tau. This pattern was also typical for the APOE ɛ4 carriers, who had lower levels of Aß1-42 than the noncarriers in the AD-D and MCI groups. The levels of T-tau and P-tau were significantly higher in the APOE ɛ4 carriers than in the noncarriers, but only in the MCI patients. The AVLT performance in the whole study samples was predicted by age, Aß1-42, and the T-tau CSF biomarkers, but not by the APOE genotyping.

CYP46: a risk factor for Alzheimer's disease or a coincidence?

Excess cholesterol is removed from the brain via hydroxylation mediated by cholesterol 24S-hydroxylase (CYP46). Although serum and cerebrospinal fluid (CSF) concentrations of 24S-hydroxycholesterol are altered during the progress of Alzheimer's disease, studies carried out to date in different populations on the association of CYP46 gene polymorphisms and risk of AD have been inconclusive. In this report, we analyzed CYP46 polymorphisms in 215 Polish AD cases and 173 healthy individuals. A fragment of CYP46 intron 2 was amplified by PCR reaction and sequenced. We discovered a new single nucleotide substitution in CYP46 intron 2, but found no difference in particular genotype or allele frequencies between AD patients and controls. However, the GG genotype of the known rs754203 polymorphic site might be a risk factor for AD, especially in APOE varepsilon4 carriers. Interestingly, in AD patients the rs754203 G allele was more frequent in males than in females. However, considering the extreme divergence of results obtained by different authors, a clear connection between the CYP46 gene and AD is questionable.

The Frequency of c.550delA Mutation of the CANP3 Gene in the Polish LGMD2A Population.

BACKGROUND: Limb girdle muscular dystrophy 2A (LGMD2A) is the most frequent LGMD variant in the European population, representing about 40% of LGMD. The c.550delA mutation in the CANP3 (calcium activated neutral protease 3) gene is the most commonly reported mutation in LGMD2A. Prevalence of this mutation in the Polish population has not been previously investigated. The aim of this study was to identify and estimate the frequency of the c.550delA mutation in Polish LGMD2A patients. METHODS: Polymerase chain reaction-sequencing analysis, restriction fragment length polymorphism polymerase chain reaction method. RESULTS: We analyzed 76 families affected with LGMD and identified 62 probands with mutations in the CANP3 gene. C.550delA was the most common mutation identified, being found in 78% of the LGMD2A families. The remaining mutations observed multiple times were as follows: c.598-612del15ntd; c.2242C>T; c.418dupC; c.1356insT, listed in terms of decreasing frequency. Two novel variants in the CANP3 gene, that is, c.700G>A Gly234Arg and c.661G>A Gly221Ser were also characterized. Overall, mutations in the LGMD2A gene were estimated to be present in 81% of patients with the LGMD phenotype who were without sarcoglycans and dysferlin deficiency on immunocytochemical analysis. The frequency of the heterozygous c.550delA mutation in the healthy Polish population was estimated at 1/124. CONCLUSIONS: The c.550delA is the most frequent CANP3 mutation in the Polish population, thus sequencing of exon 4 of this gene could identify the majority of LGMD2A patients in Poland.

Plasma leptin levels and free leptin index in women with Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by irreversible and progressive loss of memory and other cognitive functions. Controversies still exist on the precise mechanisms contributing to neurodegeneration. Obesity and disturbances in metabolic homeostasis are thought to be AD risk factors. Adipokine leptin has receptors in the brain, also in the regions related to AD. Leptin may protect against AD. The aim was to assess leptin and soluble leptin receptor levels in plasma as well as free leptin index (FLI) in correlation with metabolic status of women diagnosed with Alzheimer's disease. Eighteen women with moderate to severe stage of AD, 40 women with AD at early stage, and 42 female controls, matched for age and body mass index, participated in the study. Leptin and soluble leptin receptor levels were measured with RIA and IRMA, respectively. Then, FLI was calculated. In addition, metabolic parameters (lipid profile, glucose and insulin concentrations, HOMA-IR) were estimated. Clinical and anthropometric data were collected. The Mini-Mental State Examination (MMSE) as a cognitive impairment measurement was performed. Correlations with both leptin and FLI, and MMSE, clinical and biochemical parameters were evaluated. Leptin levels and FLI were significantly lower and leptin receptor concentrations were higher in AD subjects when compared with the controls. In AD group leptin, soluble leptin receptor and FLI correlated with selected metabolic parameters but not with MMSE. We conclude that alterations in leptin, leptin receptor, and FLI were the most intensified in advanced AD. However, these results did not correlate with dementia stage measured with MMSE. Therefore, further intensive research is needed to explain the mechanisms involved in this phenomenon.