A nucleic acid vector comprising a coding sequence for telomerase reverse transcriptase (TERT) for use in treating myocardial infarction, wherein the vector is an adeno-associated virus-based non-integrative vector and wherein a) TERT is encoded by i) a nucleic acid sequence comprising the sequence of SEQ ID NO:1 or SEQ ID NO:3, or ii) a nucleic acid which encodes a polypeptide that has 50% or more TERT activity compared to TERT encoded by SEQ ID NO:1 or SEQ ID NO:3, and which has at least 75% identity to SEQ ID NO:1 or SEQ ID NO:3, or iii) a nucleic acid sequence which is a fragment of SEQ ID NO:1 or SEQ ID NO:3 that has TERT activity and which has at least 75% identity to the sequence of SEQ ID NO:1 or SEQ ID NO:3 over the entire length of the fragment; or b) TERT comprises i) an amino acid sequence of SEQ ID NQ:2 or SEQ ID NQ:4, or ii) a polypeptide which displays 50% or more TERT activity compared to TERT of SEQ ID NO:2 or SEQ ID NO:4 and which has at least 75% identity to SEQ ID NO:2 or SEQ ID NO:4, or iii) a polypeptide which is a fragment of SEQ ID NO:2 or SEQ ID NO:4 that has TERT activity and which has at least 75% identity to the sequence of SEQ ID NO:2 or SEQ ID NO:4 over the entire length of the fragment. a) TERT is encoded by i) a nucleic acid sequence comprising the sequence of SEQ ID NO:1 or SEQ ID NO:3, or ii) a nucleic acid which encodes a polypeptide that has 50% or more TERT activity compared to TERT encoded by SEQ ID NO:1 or SEQ ID NO:3, and which has at least 75% identity to SEQ ID NO:1 or SEQ ID NO:3, or iii) a nucleic acid sequence which is a fragment of SEQ ID NO:1 or SEQ ID NO:3 that has TERT activity and which has at least 75% identity to the sequence of SEQ ID NO:1 or SEQ ID NO:3 over the entire length of the fragment; or i) a nucleic acid sequence comprising the sequence of SEQ ID NO:1 or SEQ ID NO:3, or ii) a nucleic acid which encodes a polypeptide that has 50% or more TERT activity compared to TERT encoded by SEQ ID NO:1 or SEQ ID NO:3, and which has at least 75% identity to SEQ ID NO:1 or SEQ ID NO:3, or iii) a nucleic acid sequence which is a fragment of SEQ ID NO:1 or SEQ ID NO:3 that has TERT activity and which has at least 75% identity to the sequence of SEQ ID NO:1 or SEQ ID NO:3 over the entire length of the fragment; or b) TERT comprises i) an amino acid sequence of SEQ ID NQ:2 or SEQ ID NQ:4, or ii) a polypeptide which displays 50% or more TERT activity compared to TERT of SEQ ID NO:2 or SEQ ID NO:4 and which has at least 75% identity to SEQ ID NO:2 or SEQ ID NO:4, or iii) a polypeptide which is a fragment of SEQ ID NO:2 or SEQ ID NO:4 that has TERT activity and which has at least 75% identity to the sequence of SEQ ID NO:2 or SEQ ID NO:4 over the entire length of the fragment. i) an amino acid sequence of SEQ ID NQ:2 or SEQ ID NQ:4, or ii) a polypeptide which displays 50% or more TERT activity compared to TERT of SEQ ID NO:2 or SEQ ID NO:4 and which has at least 75% identity to SEQ ID NO:2 or SEQ ID NO:4, or iii) a polypeptide which is a fragment of SEQ ID NO:2 or SEQ ID NO:4 that has TERT activity and which has at least 75% identity to the sequence of SEQ ID NO:2 or SEQ ID NO:4 over the entire length of the fragment.