{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T13:09:12Z","timestamp":1779887352622,"version":"3.53.1"},"reference-count":53,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T00:00:00Z","timestamp":1779840000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Unexplained infertility affects up to 30% of couples and has been associated with heat shock proteins (HSP) and endometrial stress. HSPs and their co-chaperones are part of a complex network of proteins responsible for maintaining protein homeostasis and cell survival. This exploratory hypothesis-generating study investigated the possible relationship between HSPs and unexplained infertility. Twenty-five women were recruited from an IVF clinic. Eleven were confirmed for unexplained infertility (UI), while fourteen were age- and body mass index (BMI)-matched couples with confirmed male factor infertility (MFI), acting as controls. Blood samples were obtained at day 21 of the luteal phase, and plasma measurement of 19 HSPs and co-chaperones undertaken using the slow off-rate modified aptamer (SomaScan) platform. Welch\u2019s t-test and a permutation test were used to compare group means, and Pearson\u2019s correlations to examine relationships with HSPs. Of the 19 proteins measured, plasma HSP70 was decreased (permutation p = 0.002) in cases with unexplained infertility, while HSC70 and STIP1 were increased (permutation p = 0.017 and p = 0.001, respectively) when compared to MFI control. HSP70 was negatively correlated to both HSC70 and STIP 1 in UI (r = \u22120.77, permutation p = 0.017; \u22120.80, permutation p = 0.003, respectively), but not in MFI, whilst HSC70 and STIP1 were positively correlated in both UI and MFI (r = 0.93, permutation p = 0.001; r = 0.65, permutation p = 0.035, respectively). The HSP70-HSC70-STIP1 axis showed HSC70-STIP1 coupling with an inverse relationship with inducible HSP70, findings that may suggest dysregulation of constitutive and stress-inducible chaperone systems in UI.<\/jats:p>","DOI":"10.3390\/ijms27114817","type":"journal-article","created":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T12:31:56Z","timestamp":1779885116000},"page":"4817","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["An Exploratory Study of Heat Shock Protein Changes in Women with Unexplained Infertility"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6501-7055","authenticated-orcid":false,"given":"Zainab","family":"Alhalwachi","sequence":"first","affiliation":[{"name":"School of Medicine, Royal College of Surgeons in Ireland, Medical University of Bahrain, Busaiteen 15503, Bahrain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3544-2231","authenticated-orcid":false,"given":"Thozhukat","family":"Sathyapalan","sequence":"additional","affiliation":[{"name":"Hull York Medical School, University of Hull, Hull HU6 7RX, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5762-3917","authenticated-orcid":false,"given":"Alexandra E.","family":"Butler","sequence":"additional","affiliation":[{"name":"School of Medicine, Royal College of Surgeons in Ireland, Medical University of Bahrain, Busaiteen 15503, Bahrain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5887-7257","authenticated-orcid":false,"given":"Stephen L.","family":"Atkin","sequence":"additional","affiliation":[{"name":"School of Medicine, Royal College of Surgeons in Ireland, Medical University of Bahrain, Busaiteen 15503, Bahrain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Nugent, C.N., and Chandra, A. (2024). Infertility and Impaired Fecundity in Women and Men in the United States, 2015\u20132019, National Health Statistics Reports.","DOI":"10.15620\/cdc\/147886"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Wei, Y., Lin, Z., Huang, Q., Wu, H., Wang, R., and Wang, J. (2025). Burden of female infertility in 204 countries and territories, 1990-2021: Results from the Global Burden of Disease Study 2021. J. Psychosom. Obstet. Gynaecol., 46.","DOI":"10.1080\/0167482X.2025.2459618"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1001\/jama.2021.4788","article-title":"Diagnosis and management of infertility: A review","volume":"326","author":"Carson","year":"2021","journal-title":"JAMA"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1038\/s41572-023-00459-w","article-title":"Male infertility","volume":"9","author":"Eisenberg","year":"2023","journal-title":"Nat. Rev. Dis. Primers"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1055\/s-0040-1721377","article-title":"The Role of Oocyte Quality in Explaining \u201cUnexplained\u201d Infertility","volume":"38","author":"Homer","year":"2020","journal-title":"Semin. Reprod. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2110","DOI":"10.1093\/humrep\/del113","article-title":"Luteinized unruptured follicle syndrome: Incidence and recurrence rate in infertile women with unexplained infertility undergoing intrauterine insemination","volume":"21","author":"Qublan","year":"2006","journal-title":"Hum. Reprod."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Schattman, G.L., Esteves, S.C., and Agarwal, A. (2015). Unexplained infertility. Female Reproductive Dysfunction, Springer.","DOI":"10.1007\/978-1-4939-2140-9"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Santamaria, X., and Sim\u00f3n, C. (2021). Endometrial factor in unexplained infertility and recurrent implantation failure. Seminars in Reproductive Medicine, Thieme Medical Publishers, Inc.","DOI":"10.1055\/s-0041-1735199"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"103848","DOI":"10.1016\/j.rbmo.2024.103848","article-title":"The prevalence of endometriosis in unexplained infertility: A systematic review","volume":"49","author":"Bafort","year":"2024","journal-title":"Reprod. Biomed. Online"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1186\/s12978-023-01578-z","article-title":"Lifestyle and environmental risk factors for unexplained male infertility: Study protocol for Australian Male Infertility Exposure (AMIE), a case\u2013control study","volume":"20","author":"Biggs","year":"2023","journal-title":"Reprod. Health"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1111\/j.1479-828X.2009.01119.x","article-title":"Lifestyle factors in people seeking infertility treatment\u2013a review","volume":"50","author":"Anderson","year":"2010","journal-title":"Aust. N. Z. J. Obstet. Gynaecol."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Guideline Group on Unexplained Infertility, Romualdi, D., Ata, B., Bhattacharya, S., Bosch, E., Costello, M., Gersak, K., Homburg, R., Mincheva, M., and Norman, R. (2023). Evidence-based guideline: Unexplained infertility. Hum. Reprod., 38, 1881\u20131890.","DOI":"10.1093\/humrep\/dead150"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1253","DOI":"10.1093\/oxfordjournals.humrep.a138689","article-title":"Expression of heat shock protein 70 kDa in human endometrium of normal and infertile women","volume":"9","author":"Nip","year":"1994","journal-title":"Hum. Reprod."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"753","DOI":"10.1007\/s12192-015-0609-9","article-title":"Interaction between the inducible 70-kDa heat shock protein and autophagy: Effects on fertility and pregnancy","volume":"20","author":"Sisti","year":"2015","journal-title":"Cell Stress Chaperones"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Singh, M.K., Shin, Y., Ju, S., Han, S., Choe, W., Yoon, K.-S., Kim, S.S., and Kang, I. (2024). Heat shock response and heat shock proteins: Current understanding and future opportunities in human diseases. Int. J. Mol. Sci., 25.","DOI":"10.3390\/ijms25084209"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2897","DOI":"10.1007\/s00018-018-2836-6","article-title":"Roles of heat shock factor 1 beyond the heat shock response","volume":"75","author":"Barna","year":"2018","journal-title":"Cell. Mol. Life Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"3894","DOI":"10.1038\/srep03894","article-title":"Uterine selection of human embryos at implantation","volume":"4","author":"Brosens","year":"2014","journal-title":"Sci. Rep."},{"key":"ref_18","first-page":"54","article-title":"The overview and role of heat shock proteins (HSP) especially HSP 60 and 70 in reproduction and other pathologies (a literature review)","volume":"26","author":"Berestoviy","year":"2021","journal-title":"Me\u0434\u0438\u0447\u043d\u0456 \u041fepc\u043fe\u043a\u0442\u0438\u0432\u0438"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Swelum, A.A.-A., Hashem, N.M., Abo-Ahmed, A.I., Abd El-Hack, M.E., and Abdo, M. (2020). The role of heat shock proteins in reproductive functions. Heat Shock Proteins in Inflammatory Diseases, Springer.","DOI":"10.1007\/7515_2020_32"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"123","DOI":"10.5534\/wjmh.2014.32.3.123","article-title":"Understanding the role of heat shock protein isoforms in male fertility, aging and apoptosis","volume":"32","author":"Purandhar","year":"2014","journal-title":"World J. Men\u2019s Health"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1136","DOI":"10.1016\/S0015-0282(01)02892-8","article-title":"Decreased expression of the heat shock protein hsp70-2 is associated with the pathogenesis of male infertility","volume":"76","author":"Feng","year":"2001","journal-title":"Fertil. Steril."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Niinuma, S.A., Lubbad, L., Lubbad, W., Moin, A.S.M., and Butler, A.E. (2023). The role of heat shock proteins in the pathogenesis of polycystic ovarian syndrome: A review of the literature. Int. J. Mol. Sci., 24.","DOI":"10.3390\/ijms24031838"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1186\/s13048-019-0548-7","article-title":"Abnormal expression of HSP70 may contribute to PCOS pathology","volume":"12","author":"Wu","year":"2019","journal-title":"J. Ovarian Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1111\/aji.12525","article-title":"Potential role of heat-shock protein 70 and interleukin-15 in the pathogenesis of threatened spontaneous abortions","volume":"76","author":"Gulic","year":"2016","journal-title":"Am. J. Reprod. Immunol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Jee, B., Dhar, R., Singh, S., and Karmakar, S. (2021). Heat Shock Proteins and Their Role in Pregnancy: Redefining the Function of \u201cOld Rum in a New Bottle\u201d. Front. Cell Dev. Biol., 9.","DOI":"10.3389\/fcell.2021.648463"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1007\/s12192-008-0067-8","article-title":"Increased serum heat-shock protein 70 levels reflect systemic inflammation, oxidative stress and hepatocellular injury in preeclampsia","volume":"14","author":"Molvarec","year":"2009","journal-title":"Cell Stress Chaperones"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1007\/s12192-014-0516-5","article-title":"The oxidation of HSP70 is associated with functional impairment and lack of stimulatory capacity","volume":"19","author":"Grunwald","year":"2014","journal-title":"Cell Stress Chaperones"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1186\/1477-7827-10-49","article-title":"The effects of oxidative stress on female reproduction: A review","volume":"10","author":"Agarwal","year":"2012","journal-title":"Reprod. Biol. Endocrinol."},{"key":"ref_29","first-page":"135","article-title":"Malonyldialdehyde and total antioxidant status in the peritoneal fluid of infertile women","volume":"70","author":"Polak","year":"1999","journal-title":"Ginekol. Pol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"839","DOI":"10.1038\/ncb0901-839","article-title":"Heat-shock protein 70 antagonizes apoptosis-inducing factor","volume":"3","author":"Ravagnan","year":"2001","journal-title":"Nat. Cell Biol."},{"key":"ref_31","unstructured":"Jurisicova, A. (1998). Programmed Cell Death During Mammalian Preimplantation Embryo Development, Genetic Regulation and Developmental Consequences. [Ph.D. Thesis, University of Toronto]."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Deka, K., and Saha, S. (2018). Regulation of mammalian HSP70 expression and stress response. Regulation of Heat Shock Protein Responses, Springer.","DOI":"10.1007\/978-3-319-74715-6_1"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"5975","DOI":"10.1038\/s41467-020-19783-w","article-title":"The Hsp70-Hsp90 co-chaperone Hop\/Stip1 shifts the proteostatic balance from folding towards degradation","volume":"11","author":"Bhattacharya","year":"2020","journal-title":"Nat. Commun."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"692","DOI":"10.1016\/j.fertnstert.2014.05.021","article-title":"Toward the identification of a subset of unexplained infertility: A sperm proteomic approach","volume":"102","author":"McReynolds","year":"2014","journal-title":"Fertil. Steril."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Dhamad, A.E., Zhou, Z., Zhou, J., and Du, Y. (2016). Systematic Proteomic Identification of the Heat Shock Proteins (Hsp) that Interact with Estrogen Receptor Alpha (ER\u03b1) and Biochemical Characterization of the ER\u03b1-Hsp70 Interaction. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0160312"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2229","DOI":"10.1210\/me.2008-0089","article-title":"Minireview: The intersection of steroid receptors with molecular chaperones: Observations and questions","volume":"22","author":"Smith","year":"2008","journal-title":"Mol. Endocrinol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"14326","DOI":"10.1073\/pnas.0505775102","article-title":"Cochaperone immunophilin FKBP52 is critical to uterine receptivity for embryo implantation","volume":"102","author":"Tranguch","year":"2005","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Smith, C.E., Tsai, Y.C., Liang, Y.H., Khago, D., Mariano, J., Li, J., Tarasov, S.G., Gergel, E., Tsai, B., and Villaneuva, M. (2021). A structurally conserved site in AUP1 binds the E2 enzyme UBE2G2 and is essential for ER-associated degradation. PLoS Biol., 19.","DOI":"10.1371\/journal.pbio.3001474"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"354","DOI":"10.1016\/j.pharmthera.2012.08.014","article-title":"Comprehensive review on the HSC70 functions, interactions with related molecules and involvement in clinical diseases and therapeutic potential","volume":"136","author":"Liu","year":"2012","journal-title":"Pharmacol. Ther."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Tang, T., Fu, J., Zhang, C., Wang, X., Cao, H., and Chen, L. (2024). Exploring the role of endoplasmic reticulum stress in recurrent spontaneous abortion: Identification of diagnostic biomarkers and immune cell interactions. Heliyon, 10.","DOI":"10.1016\/j.heliyon.2024.e38964"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"7343","DOI":"10.1038\/s41467-022-35143-2","article-title":"HSP90-CDC37-PP5 forms a structural platform for kinase dephosphorylation","volume":"13","author":"Oberoi","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"101","DOI":"10.3390\/genes4020101","article-title":"The Role of Mitogen-Activated Protein Kinase-Activated Protein Kinases (MAPKAPKs) in Inflammation","volume":"4","author":"Moens","year":"2013","journal-title":"Genes"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"15107","DOI":"10.1074\/jbc.M111204200","article-title":"HSP70 as endogenous stimulus of the Toll\/interleukin-1 receptor signal pathway","volume":"277","author":"Vabulas","year":"2002","journal-title":"J. Biol. Chem."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.jri.2018.12.001","article-title":"Involvement of ILR4\u03b1 and TLR4 in miscarriages","volume":"131","author":"Kolben","year":"2019","journal-title":"J. Reprod. Immunol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/j.fertnstert.2020.11.015","article-title":"Diagnosis and treatment of infertility in men: AUA\/ASRM guideline part I","volume":"115","author":"Schlegel","year":"2021","journal-title":"Fertil. Steril."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1016\/j.fertnstert.2020.11.016","article-title":"Diagnosis and treatment of infertility in men: AUA\/ASRM guideline part II","volume":"115","author":"Schlegel","year":"2021","journal-title":"Fertil. Steril."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Malik, H., Zamouri, S., Akkawi, S., Mehra, S., Mouaki, R., Sathyapalan, T., Nandakumar, M., Butler, A.E., and Atkin, S.L. (2025). Endothelial Protein Changes Indicative of Endometriosis in Unexplained Infertility, an Exploratory Study. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26136485"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Brennan, E., Radhi, M.K., Husain, Z.A., Sathyapalan, T., Moin, A.S.M., Butler, A.E., and Atkin, S.L. (2025). Differential Expression of Complement Pathway Components in Unexplained Infertility Versus Male Factor Infertility: Insights from an Exploratory Pilot Study. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms262010168"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.rbmo.2012.05.006","article-title":"The Alpha consensus meeting on cryopreservation key performance indicators and benchmarks: Proceedings of an expert meeting","volume":"25","author":"Medicine","year":"2012","journal-title":"Reprod. Biomed. Online"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1093\/clinchem\/18.6.499","article-title":"Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge","volume":"18","author":"Friedewald","year":"1972","journal-title":"Clin. Chem."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1007\/BF00280883","article-title":"Homeostasis model assessment: Insulin resistance and \u03b2-cell function from fasting plasma glucose and insulin concentrations in man","volume":"28","author":"Matthews","year":"1985","journal-title":"Diabetologia"},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Gold, L., Ayers, D., Bertino, J., Bock, C., Bock, A., Brody, E., Carter, J., Cunningham, V., Dalby, A., and Eaton, B. (2010). Aptamer-based multiplexed proteomic technology for biomarker discovery. PLoS ONE, 5.","DOI":"10.1038\/npre.2010.4538.1"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"14357","DOI":"10.1038\/ncomms14357","article-title":"Connecting genetic risk to disease end points through the human blood plasma proteome","volume":"8","author":"Suhre","year":"2017","journal-title":"Nat. Commun."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/27\/11\/4817\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T12:37:04Z","timestamp":1779885424000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/27\/11\/4817"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,27]]},"references-count":53,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["ijms27114817"],"URL":"https:\/\/doi.org\/10.3390\/ijms27114817","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,27]]}}}