Oleg A Alexeyev

Umeå University, Umeå, Västerbotten, Sweden

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Publications (45)182.93 Total impact

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    ABSTRACT: Mice lacking ALK activity have previously been reported to exhibit subtle behavioral phenotypes. In this study of ALK of loss of function mice we present data supporting a role for ALK in hypogonadotropic hypogonadism in male mice. We observed lower level of serum testosterone at P40 in ALK knock-out males, accompanied by mild disorganization of seminiferous tubules exhibiting decreased numbers of GATA4 expressing cells. These observations highlight a role for ALK in testis function and are further supported by experiments in which chemical inhibition of ALK activity with the ALK TKI crizotinib was employed. Oral administration of crizotinib resulted in a decrease of serum testosterone levels in adult wild type male mice, which reverted to normal levels after cessation of treatment. Analysis of GnRH expression in neurons of the hypothalamus revealed a significant decrease in the number of GnRH positive neurons in ALK knock-out mice at P40 when compared with control littermates. Thus, ALK appears to be involved in hypogonadotropic hypogonadism by regulating the timing of pubertal onset and testis function at the upper levels of the hypothalamic-pituitary gonadal axis.
    PLoS ONE 05/2015; 10(5):e0123542. DOI:10.1371/journal.pone.0123542 · 3.23 Impact Factor
  • A.C. Jahns · H. Eilers · R. Ganceviciene · O.A. Alexeyev ·
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    ABSTRACT: Background The pathogenesis of acne vulgaris is multi-factorial with increased sebum production, alteration of the quality of sebum lipids, dysregulation of the hormone microenvironment, follicular hyperkeratinisation and Propionibacterium acnes-driven inflammation as major contributory factors. Hyperproliferation of keratinocytes is believed to contribute to hypercornification and eventually leads to comedone development. While the distribution of P. acnes is relatively well documented in acneic and healthy skin, little is known on other Propionibacterium species: granulosum and avidum.Objectives This study aimed at direct visualization of three major propionibacteria directly in 117 control and 26 acneic skin samples. In addition, keratinocyte proliferation was evaluated.Methods Propionibacteria were visualized by immunofluorescence microscopy and keratinocyte proliferation was assessed by Ki67, K16 and p63 immunochemistry.ResultsP. acnes was identified in the majority of samples tested (n=68, 48%), while P. granulosum could be identified at n=12 (8%) samples and P. avidum was not detected at all. Unexpectedly, acne samples did not show higher keratinocyte proliferation than controls. Neither was there any association between bacterial colonization and expression of Ki67/K16/p63.Conclusion Our findings do not support earlier notions of follicular keratinocyte hyperproliferation as a cause of ductal hypercornification in acneic face skin. Further studies on mechanisms underlying hypercornification in acne pathogenesis are needed.This article is protected by copyright. All rights reserved.
    British Journal of Dermatology 10/2014; 172(4). DOI:10.1111/bjd.13436 · 4.28 Impact Factor
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    Anika C. Jahns · Oleg A. Alexeyev ·
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    ABSTRACT: Propionibacterium acnes is regarded as a common member of the human skin microbiome, often occurring in biofilms. Little is known about the size of bacterial biofilms in hair follicles as a few sections of biopsy tissue are routinely evaluated. Transversal sectioning provides a better opportunity for histologic analyses of hair follicles which can be followed through the different morphological levels. Direct visualization of P. acnes biofilms in hundreds of consecutive sections allowed insight into the 3D distribution in human hair follicles as well as investigating the depth of biofilm distribution within hair follicles and revealed four distinct colonization patterns of P. acnes biofilms. Results have shown that an individual P. acnes biofilm can spread for 1900 μm in a terminal hair follicle. This information can be of help while designing potential anti-biofilm treatment.This article is protected by copyright. All rights reserved.
    Experimental Dermatology 06/2014; 23(9). DOI:10.1111/exd.12482 · 3.76 Impact Factor
  • A. C. Jahns · B. Lundskog · D. Nosek · H. Killasli · L. Emtestam · O. A. Alexeyev ·

    Journal of the European Academy of Dermatology and Venereology 03/2014; 29(5). DOI:10.1111/jdv.12448 · 2.83 Impact Factor
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    ABSTRACT: Hidradenitis suppurativa (acne inverse) (HS) is a chronic skin disease primarily affecting hair follicles. The aetiology of HS is unknown, but infection is believed to play some role. This retrospective study investigated the microbial colonization directly in skin appendices in HS skin samples. Archival samples from 27 patients with HS were screened by immunofluorescence labelling with monoclonal and polyclonal antibodies against Gram-positive bacteria, Propionibacterium acnes and Propionibacterium granulosum. Fluorescence in situ hybridization was used for further species identification of Staphylococcus spp. Overall, 17 patients (63%) were found positive for bacterial colonization. Of these, 15 showed colonization in hair follicles and/or sinus tracts. The most commonly identified bacteria were DAPI labelled coccoids that were seen in 71% of the positive patients in the form of biofilms and microcolonies. P. acnes was found as biofilms in hair follicles of two patients. Staphylococcus aureus and coagulase-negative staphylococci were not detected in any sample. The results of this study indicate a common bacterial presence in HS skin lesions. Bacterial biofilms are not uncommon and their pathogenic role needs further evaluation.
    Apmis 01/2014; 122(9). DOI:10.1111/apm.12220 · 2.04 Impact Factor
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    ABSTRACT: Propionibacterium acnes (P. acnes) and Propionibacterium granulosum (P. granulosum) are common skin colonizers that are implicated as possible contributing factors in acne vulgaris development. We have established direct visualization tools for the simultaneous detection of these closely related species with immunofluorescence assay and fluorescence in situ hybridization (FISH). As proof of principle, we were able to distinguish P. acnes and P. granulosum bacteria in multi-species populations in vitro as well as in a mock skin infection model upon labelling with 16S rRNA probes in combinatorial FISH as well as with antibodies. Furthermore, we report the co-localization of P. acnes and P. granulosum in the stratum corneum and hair follicles from patients with acne vulgaris as well as in healthy individuals. Further studies on the spatial distribution of these bacteria in skin structures in various skin disorders are needed.
    Anaerobe 07/2013; 23. DOI:10.1016/j.anaerobe.2013.07.002 · 2.48 Impact Factor
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    Oleg A Alexeyev ·
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    ABSTRACT: Skin harbours large communities of colonizing bacteria. The same bacterial species can exist in different physiological states: viable, dormant, non-viable. Each physiological state can have a different impact on skin health and disease. Various analytical methodologies target different physiological states of bacteria, and this must be borne in mind while interpreting microbiological tests and drawing conclusions about possible cause-effect relationships.
    Experimental Dermatology 07/2013; 22(7):443-446. DOI:10.1111/exd.12160 · 3.76 Impact Factor
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    ABSTRACT: Folliculitis is a common inflammatory skin syndrome. Several microbial organisms have been put forward as causative agents, but few studies visualized microbes directly in inflamed hair follicles. This retrospective study investigated bacterial and fungal colonization of inflamed hair follicles in patients with clinically diagnosed non-infectious folliculitis. Skin biopsies from 39 folliculitis patients and 27 controls were screened by fluorescence in situ hybridization (FISH) using broad-range bacterial and fungal probes and by immunofluorescence microscopy using a monoclonal antibody towards Gram-positive bacteria. Specific monoclonal and polyclonal antibodies towards Staphylococcus spp. and Propionibacterium acnes were applied for further species identification. Inflamed follicles were associated with bacterial colonization in 10 samples (26%) and fungal colonization in three samples (8%). Staphylococcus spp. were observed in inflamed follicles in seven samples (18%). Two samples were positive for P. acnes, which were identified as either type II or type IB/type III. Both Staphylococcus spp. and P. acnes were seen in macrocolonies/biofilm structures. In conclusion, one-third of patients with clinically diagnosed, non-infectious folliculitis exhibited microbial colonization with predominance of Staphylococcus spp.
    Apmis 05/2013; 122(1). DOI:10.1111/apm.12103 · 2.04 Impact Factor
  • Oleg A Alexeyev · Christos C Zouboulis ·
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    ABSTRACT: Journal of Investigative Dermatology accepted article preview online, 8 March 2013; doi:10.1038/jid.2013.116.
    Journal of Investigative Dermatology 03/2013; 133(9). DOI:10.1038/jid.2013.116 · 7.22 Impact Factor
  • Anika C Jahns · Irina Golovleva · Ruth H Palmer · Oleg A Alexeyev ·

    Journal of dermatological science 12/2012; 70(1). DOI:10.1016/j.jdermsci.2012.11.592 · 3.42 Impact Factor
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    ABSTRACT: Rosacea is a common skin disease in adults affecting mainly the facial skin. Although inflammation appears to play a pathogenic role in rosacea, initiating factors are largely unknown. Microbial involvement in the development of rosacea has been suggested previously. We aimed to visualize Propionibacterium acnes in the skin compartments of rosacea patients. Facial skin biopsies from 82 rosacea patients and 25 controls were stained with a P. acnes-specific monoclonal antibody (QUBPa3). Seven of 82 patients (8.5%) tested positive for P. acnes which was present either as a biofilm (57% of positive) or a microcolony (43%) in colonized patients. Our results suggest that P. acnes does not play a major role in the pathogenesis of rosacea.
    Apmis 11/2012; 120(11):922-5. DOI:10.1111/j.1600-0463.2012.02920.x · 2.04 Impact Factor
  • O.A. Alexeyev · A.C. Jahns ·
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    ABSTRACT: A connection between acne vulgaris and Propionibacterium acnes has long been suggested. Over the years, several human skin microbiota sampling methods have been evolved and applied, e.g. swab, scrape, extraction techniques including cyanoacrylate gel sampling as well as punch biopsy. Collected samples have been processed following various methodologies ranging from culture studies to probe labelling and molecular analysis. Direct visualization techniques have recently shown the existence of anatomically distinct skin P. acnes populations: epidermal and follicular. P. acnes biofilms appear to be a common phenomenon. Current sampling approaches target different skin populations of P. acnes and the presence of microbial biofilms can influence the retrieval of P. acnes. The anatomical considerations must be taken into account while interpreting microbiological data.
    Anaerobe 08/2012; 18(5):479-83. DOI:10.1016/j.anaerobe.2012.07.001 · 2.48 Impact Factor
  • Anika C Jahns · Oleg A Alexeyev ·

    Journal der Deutschen Dermatologischen Gesellschaft 05/2012; 10(5):358-9. DOI:10.1111/j.1610-0387.2012.07878_suppl.x · 2.05 Impact Factor

  • Journal of dermatological science 03/2012; 67(1):63-6. DOI:10.1016/j.jdermsci.2012.03.004 · 3.42 Impact Factor
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    ABSTRACT: Acne vulgaris is a disorder of the sebaceous follicles. Propionibacterium acnes can be involved in inflammatory acne. This case-control study aimed at investigating the occurrence and localization of P. acnes in facial biopsies in acne and to characterize the P. acnes phylotype in skin compartments. Specific monoclonal and polyclonal antibodies were applied to skin biopsies of 38 patients with acne and matching controls to localize and characterize P. acnes and to determine expression of co-haemolysin CAMP factor, a putative virulence determinant. Follicular P. acnes was demonstrated in 18 (47%) samples from patients with acne and eight (21%) control samples [odds ratio (OR) 3·37, 95% confidence interval (CI) 1·23-9·23; P = 0·017]. In 14 (37%) samples from patients with acne, P. acnes was visualized in large macrocolonies/biofilms in sebaceous follicles compared with only five (13%) control samples (OR 3·85, 95% CI 1·22-12·14; P = 0·021). Macrocolonies/biofilms consisting of mixed P. acnes phylotypes expressing CAMP1 were detected in both case and control samples. Only four samples tested positive for the presence of Staphylococcus spp. and fungi were not observed. We have for the first time visualized different P. acnes phylotypes in macrocolonies/biofilms in sebaceous follicles of skin biopsies. Our results support the hypothesis that P. acnes can play a role in the pathogenesis of acne as acne samples showed a higher prevalence of follicular P. acnes colonization, both in terms of follicles containing P. acnes and the greater numbers of bacteria in macrocolonies/biofilms than in control samples.
    British Journal of Dermatology 02/2012; 167(1):50-8. DOI:10.1111/j.1365-2133.2012.10897.x · 4.28 Impact Factor
  • Anika C Jahns · Oleg A Alexeyev ·

    Journal der Deutschen Dermatologischen Gesellschaft 01/2012; 10(5):358. DOI:10.1111/j.1610-0387.2012.07878.x · 2.05 Impact Factor
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    ABSTRACT: The immune stimulating bacterium Propionibacterium acnes is a frequent colonizer of benign and malignant prostate tissue. To understand the pathogenesis of the earliest phase of this infection, we examined the P. acnes triggered immune response in cultivated prostate epithelial cells. Prostate epithelial cells are triggered to secrete IL-6, IL-8 and GM-CSF when infected with P. acnes. The secretion of cytokines is accompanied by NFkappaB related upregulation of the secreted cytokines as well as several components of the TLR2-NFkappaB signaling pathway. P. acnes has potential to trigger a strong immune reaction in the prostate glandular epithelium. Upon infection of prostate via the retrograde urethral route, the induced inflammatory reaction might facilitate bacterial colonization deeper in the prostate tissue where persistent inflammation may impact the development of prostate diseases as hyperplasia and/or malignancy.
    BMC Microbiology 04/2010; 10(1):126. DOI:10.1186/1471-2180-10-126 · 2.73 Impact Factor
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    ABSTRACT: The conversion of soluble peptides and proteins into polymeric amyloid structures is a hallmark of many age-related degenerative disorders, including Alzheimer's disease, type II diabetes and a variety of systemic amyloidoses. We report here that amyloid formation is linked to another major age-related phenomenon--prostate tissue remodelling in middle-aged and elderly men. By using multidisciplinary analysis of corpora amylacea inclusions in prostate glands of patients diagnosed with prostate cancer we have revealed that their major components are the amyloid forms of S100A8 and S100A9 proteins associated with numerous inflammatory conditions and types of cancer. In prostate protease rich environment the amyloids are stabilized by dystrophic calcification and lateral thickening. We have demonstrated that material closely resembling CA can be produced from S100A8/A9 in vitro under native and acidic conditions and shows the characters of amyloids. This process is facilitated by calcium or zinc, both of which are abundant in ex vivo inclusions. These observations were supported by computational analysis of the S100A8/A9 calcium-dependent aggregation propensity profiles. We found DNA and proteins from Escherichia coli in CA bodies, suggesting that their formation is likely to be associated with bacterial infection. CA inclusions were also accompanied by the activation of macrophages and by an increase in the concentration of S100A8/A9 in the surrounding tissues, indicating inflammatory reactions. These findings, taken together, suggest a link between bacterial infection, inflammation and amyloid deposition of pro-inflammatory proteins S100A8/A9 in the prostate gland, such that a self-perpetuating cycle can be triggered and may increase the risk of malignancy in the ageing prostate. The results provide strong support for the prediction that the generic ability of polypeptide chains to convert into amyloids could lead to their involvement in an increasing number of otherwise apparently unrelated diseases, particularly those associated with ageing.
    PLoS ONE 02/2009; 4(5):e5562. DOI:10.1371/journal.pone.0005562 · 3.23 Impact Factor
  • Oleg Alexeyev · Jan Olsson · Fredrik Elgh ·

    Urology 05/2008; 73(2):220-4. DOI:10.1016/j.urology.2008.02.052 · 2.19 Impact Factor
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    ABSTRACT: Prostate tissues from patients with prostate cancer and benign prostatic hyperplasia (BPH) frequently contain histological inflammation, and a proportion of these patients show evidence of Propionibacterium acnes infection in the prostate gland. We developed a multicolor fluorescent in situ hybridization (FISH) assay targeting P. acnes 23S rRNA along with a 14-kb region of the P. acnes genome. This assay was used to analyze prostate tissues from patients with prostate cancer and BPH. P. acnes infection of the prostate gland was demonstrated in prostatic tissue in 5 of 10 randomly selected prostate cancer patients. FISH analysis and confocal laser microscopy imaging revealed intracellular localization and stromal biofilm-like aggregates as common forms of P. acnes infection in prostate tissues from both prostate cancer and BPH patients. A sequential analysis of prostate tissue from individual patients suggested that P. acnes can persist for up to 6 years in the prostate gland. These results indicate that P. acnes can establish a persistent infection in the prostate gland. Further study is needed to clarify the link between this bacterium and prostatic inflammation which may contribute to the development of BPH and prostate cancer.
    Journal of Clinical Microbiology 12/2007; 45(11):3721-8. DOI:10.1128/JCM.01543-07 · 3.99 Impact Factor

Publication Stats

640 Citations
182.93 Total Impact Points


  • 1996-2015
    • Umeå University
      • • Department of Medical Biosciences
      • • Department of Clinical Microbiology
      Umeå, Västerbotten, Sweden
  • 1994-1999
    • Samara State Medical University
      Kuibyshev, Samara, Russia
  • 1997
    • Samara State University
      Kuibyshev, Samara, Russia