Can Adipokine FAM19A5 Be a Biomarker of Metabolic Disorders?

Aim

One of the most critical functions of adipose tissue is the production of adipokines, ie, numerous active substances that regulate metabolism. One is the newly discovered FAM19A5, whose older name is TAFA-5.

Purpose

The study aimed to review the literature on the FAM19A5 protein.

Methods

The review was conducted in December 2023 using the PubMed (Medline) search engine. Sixty-four papers were included in the review.

Results

This protein exhibits the characteristics of an adipokine with positive features for maintaining homeostasis. The results showed that FAM19A5 was highly expressed in adipose tissue, with mild to moderate expression in the brain and ovary. FAM19A5 may also inhibit vascular smooth muscle cell proliferation and migration through the perivascular adipose tissue paracrine pathway. Serum levels of FAM19A5 were decreased in obese children compared with healthy controls. There are negative correlations between FAM19A5, body mass index, and fasting insulin. Serum FAM19A5 level is correlated with type 2 diabetes, waist circumference, waist-to-hip ratio, glutamic pyruvic transferase, fasting plasma glucose, HbA1c, and mean shoulder pulse wave velocity. FAM19A5 expression was reduced in mice with obesity. However, the data available needs to be clarified or contradictory.

Conclusion

Considering today's knowledge about FAM19A5, we cannot consider this protein as a biomarker of the metabolic syndrome. According to current knowledge, FAM19A5 cannot be considered a marker of metabolic disorders because the results of studies conducted in this area are unclear.

Does metabolically healthy obesity exist? A 32-year-old man with BMI 78 kg/m2 - to treat or not to treat?

Not required for Clinical Vignette.

Resistin is not a useful insulin resistance marker for non-obese patients

Resistin, an adipokine produced in fat tissue, may be linked to insulin resistance (IR) and type 2 diabetes. Previous data are controversial and have focused mainly on obese patients. We aimed to evaluate whether resistin plays a role in the development of IR in normal-weight individuals. The study involved 77 normal-weight participants. We defined IR using different indexes and cut-off points. Resistin, fasting insulin, glucose, and lipids concentrations and anthropometric parameters were measured. Serum resistin concentration was not associated with IR. Resistin concentration was weakly related to age in all insulin-sensitive groups and low-density lipoprotein cholesterol concentration in all IR groups. Moreover, a weak negative correlation between high-density lipoprotein cholesterol and resistin concentrations was observed in the IR group categorised by the 1.69 cut-off of the homeostasis model assessment of IR. The data suggest that resistin is not a useful marker for the prediction of IR in normal-weight individuals.

The criteria of the identification of metabolic obesity among people with normal body weight and their use in everyday practice

Obesity and the metabolic syndrome caused by it constitute one of the biggest health issues of the 21st century. However, a problem of “a concealed form of obesity” — metabolic obesity with a normal body weight, which manifests clinically through the occurrence of metabolism disorders related to obesity among people with a normal body mass index — was pointed out in the 1980s. This affliction entails similar health consequences and causes many more problems in diagnosis and early treatment because a lack of obesity does not make doctors search for the traits of metabolic syndrome among seemingly healthy patients. The aim of this study is to present a proposition of diagnostic criteria for this disease in the historical perspective and to consider the possibilities of their use in everyday clinic practice.

The first detection of Neospora caninum DNA in the colostrum of infected cows

Limited data is available on the vertical transmission of Neospora caninum via the colostrum. The results of our previous research revealed the presence of N. caninum DNA in the milk of seropositive cows. The aim of the present work is to demonstrate parasite DNA in colostrum samples. A polymerase chain reaction using Np21 and Np6 primers was applied to DNA isolated from the colostrum sediment in order to amplify the corresponding genomic Nc-5 region. The expected 328-bp product was obtained in colostrum samples collected both on the calving day and the day after. This is the first detection of N. caninum DNA in the colostrum of seropositive cows, and these findings implicate the possibility of N. caninum transmission through the colostrum.

[Methods and tools for parasite differentiation within the genus Trichinella]

This review summarizes the major biological, biochemical and molecular methods which have been developed during last 20 years to distinguish parasites of the genus Trichinella. From the time of the discovery of Trichinella in 1835 until the 1970, it was assumed that trichinellosis was caused by a single species of parasite, Trichinella spiralis. Many biological parameters have been compared to differentiate the parasite, such as host specificity, geographical distribution, reproductive abilities, nurse cell development and resistance to freezing. Now, investigators realize that the genus Trichinella is a much more complex group of parasites and simple biological methods are non sufficient. In order to identify and better characterize the species and genotypes of Trichinella it was necessary to develop more sensitive techniques. First, for detecting Trichinella infection immunological methods have been used, such as detection of antibodies in host blood and antigens of parasites using monoclonal antibodies against immunodominant proteins. Later, biochemical techniques have been used such as isoenzyme analysis. The main goal of these methods is to provide a simple, rapid and reproducible techniques to differentiate Trichinella parasites. For this purpose DNA-based methods appeared the best ones. Beginning with the use restriction enzymes, repetitive DNA probes for detection of parasite DNA, and later techniques based on the polymerase chain reaction (PCR), give results at the high level of sensitivity. All of this information has been used to construct a new taxonomy of the genus Thrichinella. To date, 11 taxa have been recognized in the genus: 8 species (Trichinella spiralis T1, Trichinella nativa T2, Trichinella britovi T3, Trichinella pseudospiralis T4, Trichinella murrelli T5, Trichinella nelsoni T7, Trichinella papuae T10, Trichinella zimbabwensis T 11) and additionally three genotypes whose taxonomic status is yet uncertain (T6, T8, T9). Based upon morphology, epidemiology of trichinellosis, geographical distribution and host range of the parasite, two main groups are recognized in the genus Trichinella. The first group comprises species that encapsulate in host muscle tissue, while the species of the second group do not encapsulate. The species and genotypes of the first group infect only mammals (T. spiralis, T. nativa, T. britovi, T. murrelli, T. nelsoni, T6, T8 and T9), whereas of the three species from the second group, one parasitizes mammals and birds (T. pseudospiralis) and the other two infect mammals and reptiles (T. papuae and T. zimbabwensis). Due to the big genetic differences between Trichinella isolates, investigators predict that the number of species and genotypes found within Trichinella will be increased.

Antibodies to Neospora caninum in the blood of European bison (Bison bonasus bonasus L.) living in Poland

The prevalence of antibodies to Neospora caninum was examined in European bison (Bison bonasus bonasus L.) living in free and fenced areas in Poland. Sera of 320 European bison, different ages and sexes, from breeding areas in Poland were tested for N. caninum antibodies using ELISA test. Positive antibody responses were found in 23 bison (prevalence 7.3%). Additionally, all positive sera were tested by Western blot to verify the ELISA results. The Western blot results confirmed the presence of antibodies to Neospora tachyzoites antigens in all 23 sera tested. The antibodies were detected against a wide range of NC-1 tachyzoite antigens. The antibody responses were directed against proteins at: 9.5, 17, 21, 27, 31, 36.5, 38, 40, 43, 47, 48.5, 53.5 and 58 kDa. The most heavily stained bands had molecular weights of 9.5, 17, 27 and 58 kDa. The most important is that antibody to N. caninum was detected for the first time in sera from bison cow shot in 1988. It is the year of recognition of this protozoan parasite. Our results indicate strongly the presence of N. caninum in European bison in Poland and suggest that a sylvatic cycle of N. caninum can exist. However, further studies are needed to evaluate the existence of a sylvatic cycle of N. caninum. The study on the effect of the infection on the health status and conservation of European bison should be taken under consideration too.

Molecular identification of Trichinella spiralis and Trichinella britovi by diagnostic multiprimer large mitochondrial rRNA amplification

Trichinella parasites with different epidemiological features still occur in Europe and four species of genus Trichinella have been identified: T. spiralis, T. britovi, T. nativa and T. pseudospiralis. Until now, two of them, T. spiralis and T. britovi, have been identified in Poland. In our studies we selected sequence coding for large mitochondrial rRNA (mt LrDNA) as a genetic marker and developed a sensitive LrDNA multiprimer PCR assay allowing for rapid identification of T. spiralis and T. britovi, parasites present in wild and domestic animals in Poland.