Human Sperm Cryopreservation as an Alternative to the Decline of Sperm Quality With Aging

September 8, 2026 updated by: IVI Murcia
This observational study will evaluate whether sperm cryopreservation can help preserve sperm quality and molecular characteristics that may be affected by increasing paternal age. Men aged 18 years and older will provide a semen sample and a blood sample for laboratory analysis. Each semen sample will be divided into fresh, slow-frozen, and vitrified aliquots. The study will compare sperm quality (as assessed by computer-assisted sperm analysis), DNA methylation profiles, DNA fragmentation, sperm telomere length before and after cryopreservation. The effects of age on these parameters will also be assessed. The impact of age on seminal plasma extracellular vesicle composition and blood cell telomere length will also be analysed. The goal is to determine whether sperm cryopreservation may represent a strategy for preserving sperm characteristics associated with younger paternal age.

Study Overview

Status

Recruiting

Conditions

Detailed Description

The aging process is associated with declining fertility and increased risks of adverse reproductive and offspring health outcomes. Although the effects of maternal age have been extensively studied, the impact of paternal aging on sperm quality, reproductive outcomes, and molecular characteristics of sperm remains incompletely understood.

The primary objective of this study is to evaluate whether sperm cryopreservation may serve as an alternative to the use of sperm collected at older ages in assisted reproduction treatments. The primary endpoint is the difference in sperm DNA methylation patterns between fresh ejaculated samples and samples subjected to cryopreservation. Cryopreservation will be considered a potentially valid strategy if DNA methylation patterns remain substantially preserved following the cryopreservation process.

At least 45 male participants will be recruited and grouped according to age. Participants will provide one semen sample and a peripheral blood sample. Following routine semen analysis, each semen sample will be divided into three aliquots: fresh, slow-frozen, and vitrified. Cryopreserved aliquots will be stored in liquid nitrogen and subsequently thawed or warmed for analysis.

Standard semen parameters, including volume, concentration, motility, sperm kinetics, and morphology, will be evaluated. Additional analyses will include sperm DNA methylation, DNA fragmentation, telomere length, and characterization of extracellular vesicles and their composition. Identical assessments will be performed on fresh and cryopreserved samples to compare the effects of slow freezing and vitrification.

Secondary objectives include evaluating age-related differences in semen quality and molecular biomarkers, identifying markers associated with biological gamete age, characterizing age-related differences in seminal extracellular vesicles, and exploring associations between sperm molecular characteristics and lifestyle. Participants will also complete validated questionnaires regarding lifestyle and dietary habits.

Study Type

Observational

Enrollment (Estimated)

45

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Adult men aged 18-65 years attending IVI Murcia for semen analysis, fertility assessment, semen donation, or assisted reproduction treatment who meet the study eligibility criteria and provide informed consent. Participants will provide semen and blood samples for laboratory assessment of sperm quality and molecular characteristics before and after cryopreservation.

Description

Inclusion Criteria:

  • Male participants aged 18 to 65 years
  • Attending IVI Murcia for semen analysis and/or assisted reproduction treatment
  • Able and willing to provide written informed consent
  • Willing to provide a semen sample and a blood sample for research purposes

Exclusion Criteria:

  • Previous diagnosis of azoospermia or severe oligozoospermia (sperm concentration <1 million sperm/mL)
  • Known chromosomal abnormality (abnormal karyotype)
  • Known Y chromosome microdeletion
  • Febrile illness within the previous 3 months
  • Presence of varicocele
  • Current use of vitamin or antioxidant supplements intended to improve semen quality

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Men aged 18-39 years
Male participants aged 18-39 years who provide semen and blood samples for laboratory assessment of sperm quality and molecular characteristics. Semen samples are divided into fresh, slow-frozen, and vitrified aliquots for comparative analysis.
Men aged 40-49 years
Male participants aged 40-49 years who provide semen and blood samples for laboratory assessment of sperm quality and molecular characteristics. Semen samples are divided into fresh, slow-frozen, and vitrified aliquots for comparative analysis.
Men aged ≥50 years
Male participants aged 50 years and older who provide semen and blood samples for laboratory assessment of sperm quality and molecular characteristics. Semen samples are divided into fresh, slow-frozen, and vitrified aliquots for comparative analysis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sperm DNA methylation profile
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
DNA methylation levels of a predefined nine-gene panel measured by pyrosequencing with duplicate measurements and compared between fresh, slow-frozen, and vitrified sperm samples.
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sperm concentration
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Sperm concentration (million sperm/mL) measured using computer-assisted sperm analysis (CASA).
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Total sperm motility
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Percentage of motile sperm measured using CASA.
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Progressive sperm motility
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Percentage of progressively motile sperm measured using computer-assisted sperm analysis (CASA).
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Normal sperm morphology
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Percentage of sperm with normal morphology assessed by microscopic evaluation of stained slides according to World Health Organization (WHO) criteria.
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Sperm DNA fragmentation
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
DNA fragmentation measured in fresh, slow-frozen, and vitrified sperm samples.
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Sperm telomere length
Time Frame: Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Sperm telomere length measured in fresh, slow-frozen, and vitrified sperm samples.
Baseline (study semen collection visit) and after thawing of cryopreserved semen samples, through study completion (up to 9 months).
Seminal plasma extracellular vesicle composition
Time Frame: Baseline (study semen collection visit).
Characterization of seminal plasma extracellular vesicle composition in fresh semen samples.
Baseline (study semen collection visit).

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blood leukocyte telomere length
Time Frame: Baseline (study blood collection visit).
Blood cell telomere length measured to investigate its relationship with participant age and sperm molecular characteristics.
Baseline (study blood collection visit).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

IVI Murcia

Collaborators

European Union

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 10, 2026

Primary Completion (Estimated)

March 31, 2027

Study Completion (Estimated)

September 30, 2027

Study Registration Dates

First Submitted

June 29, 2026

First Submitted That Met QC Criteria

September 8, 2026

First Posted (Actual)

September 10, 2026

Study Record Updates

Last Update Posted (Actual)

September 10, 2026

Last Update Submitted That Met QC Criteria

September 8, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2303-MUR-046-JM
  • 101120126 (Other Grant/Funding Number: European Union Horizon Europe Programme - Marie Skłodowska-Curie Actions Doctoral Network AFRODITA)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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